Pathfinder
Editor, Senior Moderator
[h=1]Canadian Recommendations on the Prevention and Treatment of Zika Virus[/h] Prepared by the Committee to Advise on Tropical Medicine and Travel
Organization: Public Health Agency of Canada
Date published: 2016-02-08
[h=2]Related Topics[/h]
[h=2]Table of contents:[/h]
Currently, the significant and emerging concern about ZIKV is the spatial and temporal clustering of the ZIKV outbreak in Brazil with an increase in the incidence of children born with microcephaly Footnote4. This association has been supported in a small number of cases, through detection of ZIKV viral genome in amniotic fluid, placenta and tissues of affected fetuses and neonates Footnote5. In addition, an apparent increase in cases of Guillain-Barr? syndrome has been noted in ZIKV affected areas of Brazil and El Salvador, and previously in French Polynesia Footnote6.
The purposes of this statement are: to review the current understanding of ZIKV infection; and, to provide guidance for health care practitioners who provide advice to Canadians travelling to or living in affected areas and/or who manage travellers returning from these areas. Emphasis is placed on the sub-populations who appear to be at the greatest risk for ZIKV-associated harm, pregnant women and their developing fetuses.
[h=2]Methods[/h] This statement was developed by a working group of the Committee to Advise on Tropical Medicine and Travel (CATMAT). In addition to CATMAT members, the working group included representatives from the Public Health Agency of Canada and the Society of Obstetricians and Gynaecologists of Canada. Each member was a volunteer, and none declared a relevant conflict of interest. The statement complements several existing CATMAT statements including the Statement on Personal Protective Measures to Prevent Arthropod bites Footnote7 and the Statement on Pregnancy and Travel Footnote8. A thorough literature search for relevant evidence related to ZIKV was conducted. Guidelines and reports from international and national public health organizations including, but not limited to, the Centers for Disease Control in the United States, the Pan American Health Organization and the World Health Organization were also reviewed.
[h=2]Epidemiology of Zika worldwide[/h] ZIKV was first isolated from Ugandan monkeys in 1947. Soon after (1952), human infections were detected in Uganda and Tanzania Footnote9,Footnote10. However, subsequent human infections were rarely reported until 2007, when the first major outbreak of ZIKV disease was reported on the island of Yap (Micronesia) in the southwestern Pacific Ocean Footnote11. This was the first time that ZIKV was detected outside of Africa and Asia. Between 2013 and 2015, several significant outbreaks occurred on islands and archipelagos from the Pacific region including a large outbreak in French Polynesia Footnote12,Footnote13. An outbreak was also reported in Cape Verde Footnote14. In 2014, the first report of local transmission in the Americas was reported on Easter Island Footnote15. It has since spread to a wide region of the Americas including, at the time of writing, more than 20 countries and territories Footnote16. In some situations transmission has been intense, for example the Brazilian Ministry of Health has estimated that 440,000 to 1,300,000 ZIKV infections occurred in Brazil in 2015 Footnote6. It is anticipated that ZIKV will continue to spread through the Americas, in particular in tropical and subtropical regions Footnote17, Footnote18.
[h=3]Transmission[/h] The mosquitoes associated with ZIKV can be active during the day and night, with biting activity often peaking in the morning and later in the afternoon. In vertebrate hosts, the incubation period is usually three to 12 days, with blood viremia (the period when ZIKV is present in the blood) usually lasting for three to five days. If bitten by a competent mosquito while viremic, the human (or other) host can infect the mosquito thereby completing the transmission cycle Footnote18. Vertical transmission between mother and developing fetus also presumably occurs during this period Footnote19, Footnote20. Other routes of transmission include blood product transfusion Footnote21 and possibly sexual contact; the virus has been detected in semen and several cases of sexual transmission have been reported Footnote22 - Footnote24.
[h=3]Clinical Manifestations[/h] Approximately 20-25% of those infected with ZIKV will manifest symptoms, including fever, myalgia, eye pain, and maculopapular rash Footnote11, Footnote25. Early clinical manifestations are generally similar to other arboviral infections including dengue and chikungunya, with considerable overlap in symptoms, although ZIKV infections usually have milder clinical illness Footnote25, Footnote26. Thus, the differential diagnosis of a febrile returned traveller from the Americas will likely include these arboviral entities, as well as malaria Footnote27 and other viral infections Footnote28, Footnote29.
Although rare, neurological complications, such as Guillan-Barr? syndrome (GBS), have been reported following ZIKV infection, and excess GBS cases have been noted during periods of ZIKV circulation Footnote6, Footnote30, Footnote31.
Blood viremia is estimated to last three to five days following symptom onset Footnote30, Footnote32, however viral RNA has been detected in saliva Footnote13 or urine Footnote33more than a week after clearance of blood viremia. One report demonstrated ZIKV via polymerase chain reaction (PCR) in semen collected from a patient with confirmed infection who developed hematospermia two weeks following symptom recovery Footnote22.
As described above, the recent outbreak in Brazil has been associated with microcephaly, defined as a head circumference measurement below the third percentile and disproportionate to the weight and length percentile measurements. Following infection, neutralizing antibodies for ZIKV are detectable, and, by extrapolation from other flaviviruses, immunity is presumed to be long-lived.
[h=2]Risk to Canadian travellers[/h] The Public Health Agency of Canada has recently publishedNote1 an assessment of the risk of ZIKV to Canadians travelling to affected areas in the Americas Footnote34. It makes the following statements:
At this time there is insufficient data to allow for robust estimation of the likelihood that travellers will be exposed to ZIKV in affected areas, or of the likelihood of fetal infection and fetal harm in the event that a pregnant mother is infected.
[h=2]Prevention[/h] There is no vaccine or immunoprophylaxis that protects against infections with ZIKV. Health care practitioners who provide pre-travel consultations and those who care for pregnant women and women who intend to get pregnant should outline the potential risks associated with ZIKV infection so they can make informed decisions about the risks associated with travel and an informed choice about whether or not to travel. Those who choose to travel or where travel is essential should be advised to follow strict personal protective measures (PPM) against mosquito bites at all times.
[h=3]Recommendation to all travellers[/h] CATMAT recommends that all travellers to areas where ZIKV is circulating use PPM (see below) against mosquito bites.
[h=3]Recommendation to pregnant women and those who intend to get pregnant:[/h] CATMAT recommends that all pregnant women and those who are considering attempting to get pregnant discuss their travel plans with their health care provider and consider postponing travel to areas in the Americas affected by the ZIKV outbreak. The Pan American Health Organization (PAHO) has a list and map of countries and territories with confirmed cases in the AmericasFootnote35. This outbreak is expanding and reporting may not be complete or up-to-date. For this reason some women may consider postponing travel to affected areas currently considered to have suitable conditions for sustained and high levels of ZIKV transmission, even if ZIKV is not currently being reported. This includes Mexico and most areas of South and Central America, the Caribbean, but not temperate areas of Argentina or Chile. For pregnant women who choose to travel to areas with ZIKV transmission or for whom travel cannot be avoided, strict PPM against insect bites are strongly advised (see below for more detail).
Based on current information on the incubation period and duration of viremia, and the unclear duration of viral persistence in tissues, women wishing to become pregnant should wait at least two months after their return from an affected area before trying to conceive.
There is some evidence that ZIKV can persist in semen for more than two weeks, although the true frequency and duration of viral shedding in genital secretions is not known, as a precaution, men who have travelled to an area with widespread transmission of ZIKV should use condoms with any partner who is or could become pregnant for two months after their return. Until more is known, and based on our experience with other viral infections where shedding in semen may be very prolonged, it is reasonable to consider the use of condoms for the duration of the pregnancy.
[h=3]Personal protective measures:[/h] Currently, no vaccine exists to prevent ZIKV infection.
PPM are recommended to protect all travellers to areas of risk. The mosquitoes that transmit ZIKV are often most active during daytime and evening hoursFootnote17. For this reason, PPM should be used through all hours of the day and night. Use of PPM will also provide protection against other vector-associated diseases that occur in affected areas such as malaria, dengue, and chikungunya. Recommendations for PPM can be found in CATMAT's Statement on Personal Protective Measures to Prevent Arthropod BitesFootnote7. In summary, the statement recommends the approaches outlined in the Table below.
Protect yourself from bites:
Insect repellents, insecticide treated bed nets and permethrin treated clothing/clothing treatments have been reviewed for safety in Canada and/or the United States. They are considered safe for children, pregnant and breastfeeding women if used in accordance with label directions.
[h=2]Laboratory Diagnosis[/h] Molecular testing using reverse-transcriptase real time PCR (RT-PCR) is conducted by some provincial laboratories in Canada. The National Microbiology Laboratory (NML) provides provincial support, along with confirmatory testing. Sensitivity is unknown, but presumed to be high, at least in the initial few days of illness, since ZIKV appears to circulate in the blood for the first three to five days after onset of symptoms Footnote17. ZIKV RNA may be present in urine for a few days after it is no longer detectable in blood Footnote17, Footnote36. Specificity is presumed to be high. Information about NML's guidelines and testing recommendations are available for health care professionals on the Government of Canada's website.
Serologic testing is currently performed at the NML using an IgM-based in-house enzyme immunoassay (ELISA), with confirmatory ZIKV plaque reduction neutralization test (PRNT). Antibodies appear approximately five to six days after onset of symptoms Footnote30. For the acutely unwell patient with less than 10 days of symptoms, both RT-PCR and serology should be requested. For the convalescent patient with symptom onset over 10 days ago, only serology should be requested. Appropriate diagnostic specimens for RT-PCR testing include plasma/serum, urine, cerebrospinal fluid (CSF), amniotic fluid and placental tissue. Serology is usually only performed on serum; however, viral antibodies may also be detected in CSF in some cases of neurological disease.
As ZIKV is a member of the flaviviridae, serologic tests, including the IgM ELISA assay performed by the CDC, may be cross-reactive with other flaviviruses such as dengue, West Nile, and Yellow Fever (including vaccine recipients)Footnote2. Confirmation of ZIKV therefore rests on amplification of viral RNA by RT-PCR, or by confirmatory PRNT serologic testing which is laborious and time consuming. Confirmatory testing generally requires neutralizing IgG production, which may appear later than IgM. The specificity of the IgM ELISA is limited particularly during secondary flavivirus infections, and the sensitivity is ill-defined at this time, although it is presumed to be high. Patients whose serum samples are IgM positive and are also shown to harbour ZIKV specific antibodies by a PRNT assay are confirmed cases of viral infection. It should be noted that for individuals previously infected with or vaccinated against flaviviruses may exhibit cross reactivity in PRNT tests as well and the test results may be difficult to interpret. Since dengue virus and ZIKV are transmitted by the same types of mosquitoes, co-infections with these viruses are possible. As noted above, if antibody is present against both of these viruses or other related flaviviruses, it may be difficult to determine the virus responsible for current versus previous or past infections.
PCR for ZIKV can be performed on amniotic fluid (when amniocentesis is technically feasible) to confirm infection of the fetus. At this time, the risk of adverse outcomes of pregnancy if the fetus is infected with ZIKV is unknown, so the risk of the procedure must be weighed against the benefits of this test result. A negative PCR likely means that the fetus is not actively infected at that moment, but would not eliminate the possibility of prior infection and potential injury to the fetus. It is not known when ZIKV RNA would be expected to appear in amniotic fluid after infection, nor how long it is likely to be detectable.
For postnatal diagnosis of congenital infection, PCR for ZIKV can be performed on placental tissue, umbilical cord blood or infant blood sample, and CSF for confirmation of congenital infection. It is likely, however, that infants or fetuses infected weeks prior to specimen sampling will no longer have detectable viral RNA.
[h=2]Screening and Management[/h] [h=3]Evaluation of non-pregnant travellers returning from endemic countries[/h] Testing for ZIKV infection should be considered in the diagnosis of any ill traveller with compatible epidemiologic and clinical history, when symptom onset is within three days after arrival in, to 14 days after departing from, a country where ZIKV transmission is ongoing or widespread. Testing for other similar viral infections and for malaria should also be done as appropriate.
Testing is generally not warranted for returned travellers whose clinically compatible illness has resolved, or for those who have travelled and remain asymptomatic, because of the currently limited availability of laboratory testing and uncertain benefit of such testing. Given that rare cases of neurologic disorders, including GBS, have been reported following ZIKV infection, returning travellers should be counselled to report any neurologic symptoms to their doctor. In the event of the diagnosis of GBS or other unusual neurologic syndrome, a travel history should be elicited. If ZIKV infection is thought to be potentially associated with the illness, a specialist should be consulted.
[h=3]Screening in the context of pregnancy[/h] [h=4]Evaluation of pregnant women with a travel history to a country with ongoing or widespread transmission of ZIKV[/h] Health care providers should inquire about travel history among all pregnant women. Those who have travelled to a country with ongoing or widespread transmission of ZIKV should be evaluated. Screening of pregnant women should be discussed on a case-by-case basis between the woman and her health care provider. In these discussions, it is important to consider the problems with sensitivity and specificity of currently available diagnostic testing, overall test result interpretation, as well as the prolonged turnaround time of the available tests, which may be problematic in some cases. The decision to test should include consideration of how the results of the screening tests would be used to inform subsequent decisions. Diagnosis and identification of poor fetal outcomes will allow for appropriate counselling.
Pregnant women and their partners may be justifiably concerned about the risk of ZIKV infection to their fetus and may want to receive counselling to decide the best course of action, including the question of termination. The actual risks of ZIKV infection in pregnancy are currently unclear. Specifically, the risk of symptomatic vertical infection (with microcephaly/intracranial calcification) with maternal infection in a given trimester of pregnancy is entirely unknown although it is presumed that the risk is highest in the first and early second trimester. This uncertainty makes pregnancy counselling a difficult prospect. Regardless, discussion and informed decision making regarding options for management of ZIKV infection in pregnancy (much like any other congenital infection or congenital anomaly) requires thorough consultation with a Maternal Fetal Medicine Specialist or another specialist familiar with reproductive infectious diseases. As understanding of the risks of ZIKV infection in pregnancy becomes clearer, so too will the related counselling messages, which in turn will allow each patient to make her own individual decision about her pregnancy.
Testing (including PCR) should be offered to pregnant women with acute signs and symptoms compatible with ZIKV. Likewise, a pregnant woman who has a clinical history of a compatible ZIKV-like illness either during or after travel to an area with ZIKV transmission, or whose fetus is suspected of having a congenital anomaly should also be offered testing.
Asymptomatic pregnant women with a history of travel to a country where ongoing or widespread ZIKV transmission is known or suspected should be evaluated and counselled appropriately. A detailed travel history should be taken in order to assess risk of exposure to ZIKV (eg. date, duration, type of travel, exposure to mosquito bites). Testing should be considered, however, the decision to test should include consideration of how the results would be used. Serologic testing risks false positive results on the initial IgM testing and there is a subsequent three to four week delay in completion of confirmatory testing to detect ZIKV specific antibodies. Screening by ultrasound cannot reliably detect microcephaly until late in the second trimester.
The risk of microcephaly or other adverse outcome of pregnancy for a woman known to be infected with ZIKV cannot be estimated from currently available data. Although measurements of head circumference and biparietal diameter may occur as early as 15 weeks, there is no defined gestational age by which microcephaly can be ruled out. Serial monitoring by ultrasound with close attention to measurement trends over time is recommended. It is possible that changes in intracranial anatomy may not be elucidated until well into the third trimester.
[h=4]Evaluation of the Fetus among Pregnant women diagnosed with ZIKV infection[/h] Serial ultrasounds (every 3-4 weeks) are recommended in pregnant women with confirmed or suspected (if testing results are pending) ZIKV infection in pregnancy and for asymptomatic pregnant travellers returning from ZIKV affected areas, to help define risk and counsel the mother. Should central nervous system (CNS) calcifications or fetal microcephaly be noted at ultrasonography of the asymptomatic pregnant returned traveller, then specific ZIKV testing (along with other routine testing) should be undertaken to help define the likely cause of the anomaly.
[h=4]Evaluation of the Infant born to a Woman diagnosed with ZIKV infection or with Suspected Congenital ZIKV infection[/h] Infants born to women with confirmed or suspected ZIKV infection in pregnancy, or those with microcephaly, intracranial calcifications or other symptoms of congenital ZIKV infection in whom the mother had potential geographic exposure to the virus, should be tested. This testing should include serology, PCR of serum (umbilical cord or infant sample), and PCR of placenta; if CSF is sampled, this can also be sent for PCR and serology. Infants with suspected or confirmed congenital ZIKV infection should also undergo further work-up including: routine lab tests (CBC and liver enzymes), head ultrasound, ophthalmologic examination, and hearing evaluation. Infants with confirmed congenital ZIKV infection should have neurodevelopmental monitoring throughout infancy to assess the potential for long term sequelae.
Infants born to women with symptoms of active ZIKV infection around the time of delivery are at risk for perinatal transmission of the disease. In the limited number of reported cases to date, perinatally infected infants have exhibited either no or mild symptoms and laboratory findings (rash, thrombocytopenia) Footnote19. Regardless, such infants should be monitored closely given the unclear spectrum of potential illness in this emerging infection. Testing with serology and serum PCR during acute illness is recommended. In such cases, care should be taken to ensure a thorough work up for other important and treatable causes of congenital infections, such as CMV and toxoplasma infection.
[h=2]Treatment[/h] There currently exists no specific antiviral therapy for the treatment of ZIKV infection. Treatment is supportive with antipyretics (acetaminophen in pregnancy), hydration and rest. Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) should be avoided until dengue can be ruled out to reduce the risk of hemorrhage Footnote37. Symptomatic disease typically lasts for up to 7 days. Urgent medical care is recommended for any symptoms associated with GBS, and treating health care providers should be made aware of recent travel to area with ZIKV circulation and/or symptoms of ZIKV infection.
If ZIKV infection is confirmed in the setting of pregnancy, referral to a Maternal Fetal Medicine Specialist or Infectious Disease Specialist should be made. If microcephaly, intracranial calcifications or other abnormalities are identified, appropriate counselling by a Neonatologist and Pediatric Infectious Diseases Specialist on potential neurodevelopmental outcome should be offered to parents.
[h=2]Additional resources and useful links[/h] Government of Canada ? For health professionals: Zika Virus
Government of Canada ? Travel health notice: Zika virus infection in the Americas
Pan American Health Organization ? Zika Virus Infection
[h=2]Acknowledgements[/h] This statement was developed by the Zika Working Group: Libman, M (chair), Boggild, A, Bui, Y, Brophy, J, Drebot, M, Geduld, J, Safronetz, D, Schofield, S, Tataryn, J, Vanschalkwyk, J, Yudin, M
CATMAT acknowledges and appreciates the contribution of Alex Demarsh and Tanya Christidis to the statement.
CATMAT members: McCarthy A (Chair), Acharya, A, Boggild A, Brophy J, Bui Y, Crockett M, Greenaway C, Libman M, Teitelbaum P and Vaughan S.
Liaison members: Audcent T (Canadian Paediatric Society), Gershman M (United States Centers for Disease Control and Prevention) and Pernica J (Association of Medical Microbiology and Infectious Disease Canada).
Ex officio members: Marion D (Canadian Forces Health Services Centre, Department of National Defence), McDonald P (Division of Anti-Infective Drugs, Health Canada), Schofield S (Pest Management Entomology, Department of National Defence) and Tepper M (Directorate of Force Health Protection, Department of National Defence).
Conflict of interest
None declared.
[h=2]Footnotes[/h] Note 1 This assessment will be updated as new information becomes available. Readers should therefore check the Public Health Agency of Canada's website for updated risk assessment information.
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Note 2 Likelihood and confidence terminology is explained in the Public Health Agency of Canada's risk assessment.
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[h=2]References[/h] Footnote 1 Marcondes CB, Ximenes MFF. Zika virus in Brazil and the danger of infestation by Aedes (Stegomyia) mosquitoes. Rev Soc Bras Med Trop 2015;epub.
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Footnote 2 Hayes EB. Zika virus outside Africa. Emerg Infect Dis 2009;15(9):1347-1350.
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Footnote 3 Kraemer MU, Sinka ME, Duda KA, Mylne AQ, Shearer FM, Barker CM, et al. The global distribution of the arbovirus vectors Aedes aegypti and Ae. albopictus. eLife Sciences 2015;4(e08347):1-18.
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Footnote 4 Triunfol M. A new mosquito-borne threat to pregnant women in Brazil. The Lancet Infect Dis 2016;16(2):156-157.
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Footnote 5 Schuler-Faccini L. Possible Association Between Zika Virus Infection and Microcephaly?Brazil, 2015. MMWR Morb Mortal Wkly Rep 2016;65.
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Footnote 6 European Centre for Disease Prevention and Control. Rapid risk assessment: Zika virus epidemic in the Americas: potential association with microcephaly and Guillain-Barr? syndrome; 2015. Available at: http://ecdc.europa.eu/en/publicatio...n-with-microcephaly-rapid-risk-assessment.pdf. Accessed Feb 5, 2016.
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Footnote 7 Committee to Advise on Tropical Medicine and Travel (CATMAT). Statement on Personal Protective Measures to Prevent Arthropod Bites. Can Commun Dis 2012;38(ACS-3):1-18.
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Footnote 8 Committee to Advise on Tropical Medicine and Travel (CATMAT). Statement on Pregnancy and Travel. Can Commun Dis 2010;36(ACS-2):1-44.
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Footnote 9 Dick GW. Epidemiological notes on some viruses isolated in Uganda; Yellow fever, Rift Valley fever, Bwamba fever, West Nile, Mengo, Semliki forest, Bunyamwera, Ntaya, Uganda S and Zika viruses. Trans R Soc Trop Med Hyg 1953;47(1):13-48.
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Footnote 10 Dick GWA. Zika virus (II). Pathogenicity and physical properties. Trans R Soc Trop Med Hyg 1952;46(5):521-534.
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Footnote 11 Duffy MR, Chen TH, Hancock WT, Powers AM, Kool JL, Lanciotti RS, et al. Zika virus outbreak on Yap Island, Federated States of Micronesia. New Engl J Med 2009;360(24):2536-2543.
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Footnote 12 Duffy MR, Chen TH, Hancock WT, Powers AM, Kool JL, Lanciotti RS, et al. Zika virus outbreak on Yap Island, Federated States of Micronesia. New Engl J Med 2009;360(24):2536-2543.
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Footnote 13 Musso D, Roche C, Nhan T-, Robin E, Teissier A, Cao-Lormeau V-. Detection of Zika virus in saliva. J Clin Virol 2015;68:53-55.
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Footnote 14 World Health Organization. Zika virus infection - Cape Verde; 2015. Available at: http://www.who.int/csr/don/21-december-2015-zika-cape-verde/en/. Accessed Feb 5, 2016.
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Footnote 15 Tognarelli J, Ulloa S, Villagra E, Lagos J, Aguayo C, Fasce R, et al. A report on the outbreak of Zika virus on Easter Island, South Pacific, 2014. Arch Virol 2015;epub:1-4.
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Footnote 16 Pan American Health Organization/World Health Organization. Epidemiological Update Neurological syndrome, congenital anomalies, and Zika virus infection; 2016. Available at: http://www.paho.org/hq/index.php?option=com_docman&task=doc_view&Itemid=270&gid=32879&lang=en. Accessed Feb 5, 2016.
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Footnote 17 European Centre for Disease Prevention and Control. Rapid risk assessment: Zika virus infection outbreak, French Polynesia; 2014. Available at: http://ecdc.europa.eu/en/publicatio...us-French-Polynesia-rapid-risk-assessment.pdf. Accessed Feb 5, 2016.
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Footnote 18 Bogoch II, Brady OJ, Kraemer MU, German M, Creatore MI, Kulkarni MA, et al. Anticipating the international spread of Zika virus from Brazil. Lancet 2016;387(10016):335-336.
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Footnote 19 Besnard M, Last?re S, Teissier A, Cao-Lormeau VM, Musso D. Evidence of perinatal transmission of Zika virus, French Polynesia, December 2013 and February 2014. Euro Surveill 2014;19(13):20751.
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Footnote 20 Oliveira Melo AS, Malinger G, Ximenes R, Szejnfeld PO, Alves Sampaio S, Bispo De Filippis AM. Zika virus intrauterine infection causes fetal brain abnormality and microcephaly: Tip of the iceberg? Ultrasound Obstet Gynecol 2016;47(1):6-7.
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Footnote 21 Musso D, Nhan T, Robin E, Roche C, Bierlaire D, Zisou K, et al. Potential for Zika virus transmission through blood transfusion demonstrated during an outbreak in French Polynesia, November 2013 to February 2014. Euro Surveill 2014;19(14):20761.
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Footnote 22 Musso D, Roche C, Robin E, Nhan T, Teissier A, Cao-Lormeau VM. Potential sexual transmission of Zika virus. Emerg Infect Dis 2015 Feb;21(2):359-361.
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Footnote 23 Foy BD, Kobylinski KC, Chilson Foy JL, Blitvich BJ, Travassos da Rosa A, Haddow AD, et al. Probable non-vector-borne transmission of Zika virus, Colorado, USA. Emerg Infect Dis 2011 May;17(5):880-882.
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Footnote 24 Dallas County Health and Human Services. DCHHS Reports First Zika Virus Case in Dallas County Acquired Through Sexual Transmission; 2016. Available at: http://www.dallascounty.org/departm...tCaseofZikaVirusThroughSexualTransmission.pdf. Accessed Feb 5, 2016.
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Footnote 25 Ioos S, Mallet H-, Leparc Goffart I, Gauthier V, Cardoso T, Herida M. Current Zika virus epidemiology and recent epidemics. Med Mal Infect 2014;44(7):302-307.
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Footnote 26 Villamil-G?mez WE, Gonz?lez-Camargo O, Rodriguez-Ayubi J, Zapata-Serpa D, Rodriguez-Morales AJ. Dengue, chikungunya and Zika co-infection in a patient from Colombia. J Infect Public Health 2015;epub.
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Footnote 27 Committee to Advise on Tropical Medicine and Travel (CATMAT). Canadian Recommendations for the Prevention and Treatment Of Malaria. 2014. Available at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/09vol35/35s1/index-eng.php. Accessed Feb 5, 2016.
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Footnote 28 Committee to Advise on Tropical Medicine and Travel (CATMAT). Fever in the returning international traveller initial assessment guidelines. Can Commun Dis 2011;37(ACS-2):1-24.
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Footnote 29 Shinohara K, Kutsuna S, Takasaki T, Moi ML, Ikeda M, Kotaki A, et al. Zika fever imported from Thailand to Japan, and diagnosed by PCR in the urines. J Trav Med 2016 Jan;23(1):1-3.
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Footnote 30 European Centre for Disease Prevention and Control. Zika virus infection: Factsheet for health professionals; 2015. Available at: http://ecdc.europa.eu/en/healthtopi...als/Pages/factsheet_health_professionals.aspx. Accessed Feb 5, 2016.
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Footnote 31 Oehler E, Watrin L, Larre P, Leparc-Goffart I, Last?re S, Valour F, et al. Zika virus infection complicated by guillain-barr? syndrome - case report, French Polynesia, December 2013. Euro Surveill 2014;19(9).
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Footnote 32 Balm MN, Lee CK, Lee HK, Chiu L, Koay ES, Tang JW. A diagnostic polymerase chain reaction assay for Zika virus. J Med Virol 2012;84(9):1501-1505.
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Footnote 33 Gourinat AC, O'Connor O, Calvez E, Goarant C, Dupont-Rouzeyrol M. Detection of Zika virus in urine. Emerg Infect Dis 2015;21(1):84-86.
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Footnote 34 Public Health Agency of Canada. Rapid Risk Assessment: The risk of Zika virus to Canadians; 2016. Available at: http://healthycanadians.gc.ca/publi...ctions/risks-zika-virus-risques/index-eng.php. Accessed Feb 5, 2016.
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Footnote 35 Pan American Health Organization/World Health Organization. Countries and territories with Zika autochthonous transmission in the Americas reported in 2015-2016; 2016. Available at: http://www.paho.org/hq/index.php?option=com_content&view=article&id=11603&Itemid=41696&lang=en. Accessed Feb 5, 2016.
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Footnote 36 Centers for Disease Control and Prevention (CDC). Updated diagnostic testing for Zika, chikungunya, and dengue viruses in US Public Health Laboratories; 2016. Available at: http://www.cdc.gov/zika/pdfs/denvchikvzikv-testing-algorithm.pdf. Accessed Feb 5, 2016.
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Footnote 37 Centers for Disease Control and Prevention (CDC). Clinical Evaluation & Disease; 2016. Available at: http://www.cdc.gov/zika/hc-providers/clinicalevaluation.html. Accessed Feb 5, 2016.
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Date modified: 2016-02-08
http://www.healthycanadians.gc.ca/p...on-comite-traitement-prevention/index-eng.php
Organization: Public Health Agency of Canada
Date published: 2016-02-08
[h=2]Related Topics[/h]
[h=2]Table of contents:[/h]
- Introduction
- Methods
- Epidemiology of Zika worldwide
- Risk to Canadian travellers
- Prevention
- Laboratory Diagnosis
- Screening and Management
- Evaluation of non-pregnant travellers returning from endemic countries
- Screening in the context of pregnancy
- Evaluation of pregnant women with a travel history to a country with ongoing or widespread transmission of ZIKV
- Evaluation of the Fetus among Pregnant women diagnosed with ZIKV infection
- Evaluation of the Infant born to a Woman diagnosed with ZIKV infection or with Suspected Congenital ZIKV infection
- Treatment
- Additional resources and useful links
- Acknowledgements
- References
Currently, the significant and emerging concern about ZIKV is the spatial and temporal clustering of the ZIKV outbreak in Brazil with an increase in the incidence of children born with microcephaly Footnote4. This association has been supported in a small number of cases, through detection of ZIKV viral genome in amniotic fluid, placenta and tissues of affected fetuses and neonates Footnote5. In addition, an apparent increase in cases of Guillain-Barr? syndrome has been noted in ZIKV affected areas of Brazil and El Salvador, and previously in French Polynesia Footnote6.
The purposes of this statement are: to review the current understanding of ZIKV infection; and, to provide guidance for health care practitioners who provide advice to Canadians travelling to or living in affected areas and/or who manage travellers returning from these areas. Emphasis is placed on the sub-populations who appear to be at the greatest risk for ZIKV-associated harm, pregnant women and their developing fetuses.
[h=2]Methods[/h] This statement was developed by a working group of the Committee to Advise on Tropical Medicine and Travel (CATMAT). In addition to CATMAT members, the working group included representatives from the Public Health Agency of Canada and the Society of Obstetricians and Gynaecologists of Canada. Each member was a volunteer, and none declared a relevant conflict of interest. The statement complements several existing CATMAT statements including the Statement on Personal Protective Measures to Prevent Arthropod bites Footnote7 and the Statement on Pregnancy and Travel Footnote8. A thorough literature search for relevant evidence related to ZIKV was conducted. Guidelines and reports from international and national public health organizations including, but not limited to, the Centers for Disease Control in the United States, the Pan American Health Organization and the World Health Organization were also reviewed.
[h=2]Epidemiology of Zika worldwide[/h] ZIKV was first isolated from Ugandan monkeys in 1947. Soon after (1952), human infections were detected in Uganda and Tanzania Footnote9,Footnote10. However, subsequent human infections were rarely reported until 2007, when the first major outbreak of ZIKV disease was reported on the island of Yap (Micronesia) in the southwestern Pacific Ocean Footnote11. This was the first time that ZIKV was detected outside of Africa and Asia. Between 2013 and 2015, several significant outbreaks occurred on islands and archipelagos from the Pacific region including a large outbreak in French Polynesia Footnote12,Footnote13. An outbreak was also reported in Cape Verde Footnote14. In 2014, the first report of local transmission in the Americas was reported on Easter Island Footnote15. It has since spread to a wide region of the Americas including, at the time of writing, more than 20 countries and territories Footnote16. In some situations transmission has been intense, for example the Brazilian Ministry of Health has estimated that 440,000 to 1,300,000 ZIKV infections occurred in Brazil in 2015 Footnote6. It is anticipated that ZIKV will continue to spread through the Americas, in particular in tropical and subtropical regions Footnote17, Footnote18.
[h=3]Transmission[/h] The mosquitoes associated with ZIKV can be active during the day and night, with biting activity often peaking in the morning and later in the afternoon. In vertebrate hosts, the incubation period is usually three to 12 days, with blood viremia (the period when ZIKV is present in the blood) usually lasting for three to five days. If bitten by a competent mosquito while viremic, the human (or other) host can infect the mosquito thereby completing the transmission cycle Footnote18. Vertical transmission between mother and developing fetus also presumably occurs during this period Footnote19, Footnote20. Other routes of transmission include blood product transfusion Footnote21 and possibly sexual contact; the virus has been detected in semen and several cases of sexual transmission have been reported Footnote22 - Footnote24.
[h=3]Clinical Manifestations[/h] Approximately 20-25% of those infected with ZIKV will manifest symptoms, including fever, myalgia, eye pain, and maculopapular rash Footnote11, Footnote25. Early clinical manifestations are generally similar to other arboviral infections including dengue and chikungunya, with considerable overlap in symptoms, although ZIKV infections usually have milder clinical illness Footnote25, Footnote26. Thus, the differential diagnosis of a febrile returned traveller from the Americas will likely include these arboviral entities, as well as malaria Footnote27 and other viral infections Footnote28, Footnote29.
Although rare, neurological complications, such as Guillan-Barr? syndrome (GBS), have been reported following ZIKV infection, and excess GBS cases have been noted during periods of ZIKV circulation Footnote6, Footnote30, Footnote31.
Blood viremia is estimated to last three to five days following symptom onset Footnote30, Footnote32, however viral RNA has been detected in saliva Footnote13 or urine Footnote33more than a week after clearance of blood viremia. One report demonstrated ZIKV via polymerase chain reaction (PCR) in semen collected from a patient with confirmed infection who developed hematospermia two weeks following symptom recovery Footnote22.
As described above, the recent outbreak in Brazil has been associated with microcephaly, defined as a head circumference measurement below the third percentile and disproportionate to the weight and length percentile measurements. Following infection, neutralizing antibodies for ZIKV are detectable, and, by extrapolation from other flaviviruses, immunity is presumed to be long-lived.
[h=2]Risk to Canadian travellers[/h] The Public Health Agency of Canada has recently publishedNote1 an assessment of the risk of ZIKV to Canadians travelling to affected areas in the Americas Footnote34. It makes the following statements:
- Based on the frequency of Canadian travel, the expectation of continued spread of ZIKV in the Americas, and the number of observed ZIKV cases to date, we estimate the likelihood that Canadians travelling to epidemic regions will be exposed to ZIKV as MediumNote2 (with medium confidence).
- Based on current understanding of the typical course of infection we estimate the general impact of ZIKV infection to be Low (with medium confidence).
- There is mounting evidence to support the possible link between infection with ZIKV and infant microcephaly, though much uncertainty remains. Substantial effort is being directed towards determining if there is a causal link, the effect of timing of infection on fetal development, and determining if there are other contributing risk factors (i.e. co-infection or serial infection with other viruses, nutritional status, or other environmental factors). Future scientific findings could change this judgement substantially, but if the increased incidence of microcephaly is caused by ZIKV (which is still under investigation), we estimate a Very High impact (with low confidence) on the unborn child of a woman who acquires ZIKV while pregnant Footnote34.
At this time there is insufficient data to allow for robust estimation of the likelihood that travellers will be exposed to ZIKV in affected areas, or of the likelihood of fetal infection and fetal harm in the event that a pregnant mother is infected.
[h=2]Prevention[/h] There is no vaccine or immunoprophylaxis that protects against infections with ZIKV. Health care practitioners who provide pre-travel consultations and those who care for pregnant women and women who intend to get pregnant should outline the potential risks associated with ZIKV infection so they can make informed decisions about the risks associated with travel and an informed choice about whether or not to travel. Those who choose to travel or where travel is essential should be advised to follow strict personal protective measures (PPM) against mosquito bites at all times.
[h=3]Recommendation to all travellers[/h] CATMAT recommends that all travellers to areas where ZIKV is circulating use PPM (see below) against mosquito bites.
[h=3]Recommendation to pregnant women and those who intend to get pregnant:[/h] CATMAT recommends that all pregnant women and those who are considering attempting to get pregnant discuss their travel plans with their health care provider and consider postponing travel to areas in the Americas affected by the ZIKV outbreak. The Pan American Health Organization (PAHO) has a list and map of countries and territories with confirmed cases in the AmericasFootnote35. This outbreak is expanding and reporting may not be complete or up-to-date. For this reason some women may consider postponing travel to affected areas currently considered to have suitable conditions for sustained and high levels of ZIKV transmission, even if ZIKV is not currently being reported. This includes Mexico and most areas of South and Central America, the Caribbean, but not temperate areas of Argentina or Chile. For pregnant women who choose to travel to areas with ZIKV transmission or for whom travel cannot be avoided, strict PPM against insect bites are strongly advised (see below for more detail).
Based on current information on the incubation period and duration of viremia, and the unclear duration of viral persistence in tissues, women wishing to become pregnant should wait at least two months after their return from an affected area before trying to conceive.
There is some evidence that ZIKV can persist in semen for more than two weeks, although the true frequency and duration of viral shedding in genital secretions is not known, as a precaution, men who have travelled to an area with widespread transmission of ZIKV should use condoms with any partner who is or could become pregnant for two months after their return. Until more is known, and based on our experience with other viral infections where shedding in semen may be very prolonged, it is reasonable to consider the use of condoms for the duration of the pregnancy.
[h=3]Personal protective measures:[/h] Currently, no vaccine exists to prevent ZIKV infection.
PPM are recommended to protect all travellers to areas of risk. The mosquitoes that transmit ZIKV are often most active during daytime and evening hoursFootnote17. For this reason, PPM should be used through all hours of the day and night. Use of PPM will also provide protection against other vector-associated diseases that occur in affected areas such as malaria, dengue, and chikungunya. Recommendations for PPM can be found in CATMAT's Statement on Personal Protective Measures to Prevent Arthropod BitesFootnote7. In summary, the statement recommends the approaches outlined in the Table below.
Protect yourself from bites:
- Cover up:
- Wear light-coloured, long-sleeved, loose fitting, tucked-in shirts, long pants, shoes or boots (not sandals), and a hat.
- Use insect repellent on exposed skin
- It is recommended that adults use repellents that contain DEET (20-30%) or icaridin (20%).
- It is recommended that children 6 months to twelve years of age use repellents that contain icaridin (20%). As a second choice, this age group can use repellents with age-appropriate DEET concentrations as per label.
- If bites cannot be avoided using a physical barrier, consider use of up to 10% DEET or 10% icaridin for infants under six months of age.
- Protect living areas from mosquito entry:
- Stay in a well-screened or completely enclosed air-conditioned room.
- Reduce your risk in work and accommodation areas by closing eaves, eliminating holes in roofs and walls and closing any other gaps.
- If mosquito entry into living quarters cannot be otherwise prevented (e.g. by screening):
- Use a bed net (e.g. for sleeping or resting inside), preferably treated with insecticide.
- Netting can also be used to protect children in playpens, cribs, or strollers.
- Bed nets will also provide protection against diseases like malaria.
- Apply a permethrin insecticide to clothing and other travel gear for greater protection
- Although permethrin is not available in Canada, travel health clinics can advise you how to purchase permethrin and pre-treated gear before or during your trip.
- Permethrin-treated clothing is effective through several washes.
- Always follow label instructions when using permethrin.
- Do not use permethrin directly on skin.
Insect repellents, insecticide treated bed nets and permethrin treated clothing/clothing treatments have been reviewed for safety in Canada and/or the United States. They are considered safe for children, pregnant and breastfeeding women if used in accordance with label directions.
[h=2]Laboratory Diagnosis[/h] Molecular testing using reverse-transcriptase real time PCR (RT-PCR) is conducted by some provincial laboratories in Canada. The National Microbiology Laboratory (NML) provides provincial support, along with confirmatory testing. Sensitivity is unknown, but presumed to be high, at least in the initial few days of illness, since ZIKV appears to circulate in the blood for the first three to five days after onset of symptoms Footnote17. ZIKV RNA may be present in urine for a few days after it is no longer detectable in blood Footnote17, Footnote36. Specificity is presumed to be high. Information about NML's guidelines and testing recommendations are available for health care professionals on the Government of Canada's website.
Serologic testing is currently performed at the NML using an IgM-based in-house enzyme immunoassay (ELISA), with confirmatory ZIKV plaque reduction neutralization test (PRNT). Antibodies appear approximately five to six days after onset of symptoms Footnote30. For the acutely unwell patient with less than 10 days of symptoms, both RT-PCR and serology should be requested. For the convalescent patient with symptom onset over 10 days ago, only serology should be requested. Appropriate diagnostic specimens for RT-PCR testing include plasma/serum, urine, cerebrospinal fluid (CSF), amniotic fluid and placental tissue. Serology is usually only performed on serum; however, viral antibodies may also be detected in CSF in some cases of neurological disease.
As ZIKV is a member of the flaviviridae, serologic tests, including the IgM ELISA assay performed by the CDC, may be cross-reactive with other flaviviruses such as dengue, West Nile, and Yellow Fever (including vaccine recipients)Footnote2. Confirmation of ZIKV therefore rests on amplification of viral RNA by RT-PCR, or by confirmatory PRNT serologic testing which is laborious and time consuming. Confirmatory testing generally requires neutralizing IgG production, which may appear later than IgM. The specificity of the IgM ELISA is limited particularly during secondary flavivirus infections, and the sensitivity is ill-defined at this time, although it is presumed to be high. Patients whose serum samples are IgM positive and are also shown to harbour ZIKV specific antibodies by a PRNT assay are confirmed cases of viral infection. It should be noted that for individuals previously infected with or vaccinated against flaviviruses may exhibit cross reactivity in PRNT tests as well and the test results may be difficult to interpret. Since dengue virus and ZIKV are transmitted by the same types of mosquitoes, co-infections with these viruses are possible. As noted above, if antibody is present against both of these viruses or other related flaviviruses, it may be difficult to determine the virus responsible for current versus previous or past infections.
PCR for ZIKV can be performed on amniotic fluid (when amniocentesis is technically feasible) to confirm infection of the fetus. At this time, the risk of adverse outcomes of pregnancy if the fetus is infected with ZIKV is unknown, so the risk of the procedure must be weighed against the benefits of this test result. A negative PCR likely means that the fetus is not actively infected at that moment, but would not eliminate the possibility of prior infection and potential injury to the fetus. It is not known when ZIKV RNA would be expected to appear in amniotic fluid after infection, nor how long it is likely to be detectable.
For postnatal diagnosis of congenital infection, PCR for ZIKV can be performed on placental tissue, umbilical cord blood or infant blood sample, and CSF for confirmation of congenital infection. It is likely, however, that infants or fetuses infected weeks prior to specimen sampling will no longer have detectable viral RNA.
[h=2]Screening and Management[/h] [h=3]Evaluation of non-pregnant travellers returning from endemic countries[/h] Testing for ZIKV infection should be considered in the diagnosis of any ill traveller with compatible epidemiologic and clinical history, when symptom onset is within three days after arrival in, to 14 days after departing from, a country where ZIKV transmission is ongoing or widespread. Testing for other similar viral infections and for malaria should also be done as appropriate.
Testing is generally not warranted for returned travellers whose clinically compatible illness has resolved, or for those who have travelled and remain asymptomatic, because of the currently limited availability of laboratory testing and uncertain benefit of such testing. Given that rare cases of neurologic disorders, including GBS, have been reported following ZIKV infection, returning travellers should be counselled to report any neurologic symptoms to their doctor. In the event of the diagnosis of GBS or other unusual neurologic syndrome, a travel history should be elicited. If ZIKV infection is thought to be potentially associated with the illness, a specialist should be consulted.
[h=3]Screening in the context of pregnancy[/h] [h=4]Evaluation of pregnant women with a travel history to a country with ongoing or widespread transmission of ZIKV[/h] Health care providers should inquire about travel history among all pregnant women. Those who have travelled to a country with ongoing or widespread transmission of ZIKV should be evaluated. Screening of pregnant women should be discussed on a case-by-case basis between the woman and her health care provider. In these discussions, it is important to consider the problems with sensitivity and specificity of currently available diagnostic testing, overall test result interpretation, as well as the prolonged turnaround time of the available tests, which may be problematic in some cases. The decision to test should include consideration of how the results of the screening tests would be used to inform subsequent decisions. Diagnosis and identification of poor fetal outcomes will allow for appropriate counselling.
Pregnant women and their partners may be justifiably concerned about the risk of ZIKV infection to their fetus and may want to receive counselling to decide the best course of action, including the question of termination. The actual risks of ZIKV infection in pregnancy are currently unclear. Specifically, the risk of symptomatic vertical infection (with microcephaly/intracranial calcification) with maternal infection in a given trimester of pregnancy is entirely unknown although it is presumed that the risk is highest in the first and early second trimester. This uncertainty makes pregnancy counselling a difficult prospect. Regardless, discussion and informed decision making regarding options for management of ZIKV infection in pregnancy (much like any other congenital infection or congenital anomaly) requires thorough consultation with a Maternal Fetal Medicine Specialist or another specialist familiar with reproductive infectious diseases. As understanding of the risks of ZIKV infection in pregnancy becomes clearer, so too will the related counselling messages, which in turn will allow each patient to make her own individual decision about her pregnancy.
Testing (including PCR) should be offered to pregnant women with acute signs and symptoms compatible with ZIKV. Likewise, a pregnant woman who has a clinical history of a compatible ZIKV-like illness either during or after travel to an area with ZIKV transmission, or whose fetus is suspected of having a congenital anomaly should also be offered testing.
Asymptomatic pregnant women with a history of travel to a country where ongoing or widespread ZIKV transmission is known or suspected should be evaluated and counselled appropriately. A detailed travel history should be taken in order to assess risk of exposure to ZIKV (eg. date, duration, type of travel, exposure to mosquito bites). Testing should be considered, however, the decision to test should include consideration of how the results would be used. Serologic testing risks false positive results on the initial IgM testing and there is a subsequent three to four week delay in completion of confirmatory testing to detect ZIKV specific antibodies. Screening by ultrasound cannot reliably detect microcephaly until late in the second trimester.
The risk of microcephaly or other adverse outcome of pregnancy for a woman known to be infected with ZIKV cannot be estimated from currently available data. Although measurements of head circumference and biparietal diameter may occur as early as 15 weeks, there is no defined gestational age by which microcephaly can be ruled out. Serial monitoring by ultrasound with close attention to measurement trends over time is recommended. It is possible that changes in intracranial anatomy may not be elucidated until well into the third trimester.
[h=4]Evaluation of the Fetus among Pregnant women diagnosed with ZIKV infection[/h] Serial ultrasounds (every 3-4 weeks) are recommended in pregnant women with confirmed or suspected (if testing results are pending) ZIKV infection in pregnancy and for asymptomatic pregnant travellers returning from ZIKV affected areas, to help define risk and counsel the mother. Should central nervous system (CNS) calcifications or fetal microcephaly be noted at ultrasonography of the asymptomatic pregnant returned traveller, then specific ZIKV testing (along with other routine testing) should be undertaken to help define the likely cause of the anomaly.
[h=4]Evaluation of the Infant born to a Woman diagnosed with ZIKV infection or with Suspected Congenital ZIKV infection[/h] Infants born to women with confirmed or suspected ZIKV infection in pregnancy, or those with microcephaly, intracranial calcifications or other symptoms of congenital ZIKV infection in whom the mother had potential geographic exposure to the virus, should be tested. This testing should include serology, PCR of serum (umbilical cord or infant sample), and PCR of placenta; if CSF is sampled, this can also be sent for PCR and serology. Infants with suspected or confirmed congenital ZIKV infection should also undergo further work-up including: routine lab tests (CBC and liver enzymes), head ultrasound, ophthalmologic examination, and hearing evaluation. Infants with confirmed congenital ZIKV infection should have neurodevelopmental monitoring throughout infancy to assess the potential for long term sequelae.
Infants born to women with symptoms of active ZIKV infection around the time of delivery are at risk for perinatal transmission of the disease. In the limited number of reported cases to date, perinatally infected infants have exhibited either no or mild symptoms and laboratory findings (rash, thrombocytopenia) Footnote19. Regardless, such infants should be monitored closely given the unclear spectrum of potential illness in this emerging infection. Testing with serology and serum PCR during acute illness is recommended. In such cases, care should be taken to ensure a thorough work up for other important and treatable causes of congenital infections, such as CMV and toxoplasma infection.
[h=2]Treatment[/h] There currently exists no specific antiviral therapy for the treatment of ZIKV infection. Treatment is supportive with antipyretics (acetaminophen in pregnancy), hydration and rest. Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) should be avoided until dengue can be ruled out to reduce the risk of hemorrhage Footnote37. Symptomatic disease typically lasts for up to 7 days. Urgent medical care is recommended for any symptoms associated with GBS, and treating health care providers should be made aware of recent travel to area with ZIKV circulation and/or symptoms of ZIKV infection.
If ZIKV infection is confirmed in the setting of pregnancy, referral to a Maternal Fetal Medicine Specialist or Infectious Disease Specialist should be made. If microcephaly, intracranial calcifications or other abnormalities are identified, appropriate counselling by a Neonatologist and Pediatric Infectious Diseases Specialist on potential neurodevelopmental outcome should be offered to parents.
[h=2]Additional resources and useful links[/h] Government of Canada ? For health professionals: Zika Virus
Government of Canada ? Travel health notice: Zika virus infection in the Americas
Pan American Health Organization ? Zika Virus Infection
[h=2]Acknowledgements[/h] This statement was developed by the Zika Working Group: Libman, M (chair), Boggild, A, Bui, Y, Brophy, J, Drebot, M, Geduld, J, Safronetz, D, Schofield, S, Tataryn, J, Vanschalkwyk, J, Yudin, M
CATMAT acknowledges and appreciates the contribution of Alex Demarsh and Tanya Christidis to the statement.
CATMAT members: McCarthy A (Chair), Acharya, A, Boggild A, Brophy J, Bui Y, Crockett M, Greenaway C, Libman M, Teitelbaum P and Vaughan S.
Liaison members: Audcent T (Canadian Paediatric Society), Gershman M (United States Centers for Disease Control and Prevention) and Pernica J (Association of Medical Microbiology and Infectious Disease Canada).
Ex officio members: Marion D (Canadian Forces Health Services Centre, Department of National Defence), McDonald P (Division of Anti-Infective Drugs, Health Canada), Schofield S (Pest Management Entomology, Department of National Defence) and Tepper M (Directorate of Force Health Protection, Department of National Defence).
Conflict of interest
None declared.
[h=2]Footnotes[/h] Note 1 This assessment will be updated as new information becomes available. Readers should therefore check the Public Health Agency of Canada's website for updated risk assessment information.
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Note 2 Likelihood and confidence terminology is explained in the Public Health Agency of Canada's risk assessment.
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[h=2]References[/h] Footnote 1 Marcondes CB, Ximenes MFF. Zika virus in Brazil and the danger of infestation by Aedes (Stegomyia) mosquitoes. Rev Soc Bras Med Trop 2015;epub.
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Footnote 2 Hayes EB. Zika virus outside Africa. Emerg Infect Dis 2009;15(9):1347-1350.
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Footnote 3 Kraemer MU, Sinka ME, Duda KA, Mylne AQ, Shearer FM, Barker CM, et al. The global distribution of the arbovirus vectors Aedes aegypti and Ae. albopictus. eLife Sciences 2015;4(e08347):1-18.
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Footnote 4 Triunfol M. A new mosquito-borne threat to pregnant women in Brazil. The Lancet Infect Dis 2016;16(2):156-157.
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Footnote 5 Schuler-Faccini L. Possible Association Between Zika Virus Infection and Microcephaly?Brazil, 2015. MMWR Morb Mortal Wkly Rep 2016;65.
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Footnote 6 European Centre for Disease Prevention and Control. Rapid risk assessment: Zika virus epidemic in the Americas: potential association with microcephaly and Guillain-Barr? syndrome; 2015. Available at: http://ecdc.europa.eu/en/publicatio...n-with-microcephaly-rapid-risk-assessment.pdf. Accessed Feb 5, 2016.
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Footnote 7 Committee to Advise on Tropical Medicine and Travel (CATMAT). Statement on Personal Protective Measures to Prevent Arthropod Bites. Can Commun Dis 2012;38(ACS-3):1-18.
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Footnote 8 Committee to Advise on Tropical Medicine and Travel (CATMAT). Statement on Pregnancy and Travel. Can Commun Dis 2010;36(ACS-2):1-44.
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Footnote 9 Dick GW. Epidemiological notes on some viruses isolated in Uganda; Yellow fever, Rift Valley fever, Bwamba fever, West Nile, Mengo, Semliki forest, Bunyamwera, Ntaya, Uganda S and Zika viruses. Trans R Soc Trop Med Hyg 1953;47(1):13-48.
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Footnote 10 Dick GWA. Zika virus (II). Pathogenicity and physical properties. Trans R Soc Trop Med Hyg 1952;46(5):521-534.
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Footnote 11 Duffy MR, Chen TH, Hancock WT, Powers AM, Kool JL, Lanciotti RS, et al. Zika virus outbreak on Yap Island, Federated States of Micronesia. New Engl J Med 2009;360(24):2536-2543.
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Footnote 12 Duffy MR, Chen TH, Hancock WT, Powers AM, Kool JL, Lanciotti RS, et al. Zika virus outbreak on Yap Island, Federated States of Micronesia. New Engl J Med 2009;360(24):2536-2543.
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Footnote 13 Musso D, Roche C, Nhan T-, Robin E, Teissier A, Cao-Lormeau V-. Detection of Zika virus in saliva. J Clin Virol 2015;68:53-55.
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Footnote 14 World Health Organization. Zika virus infection - Cape Verde; 2015. Available at: http://www.who.int/csr/don/21-december-2015-zika-cape-verde/en/. Accessed Feb 5, 2016.
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Footnote 15 Tognarelli J, Ulloa S, Villagra E, Lagos J, Aguayo C, Fasce R, et al. A report on the outbreak of Zika virus on Easter Island, South Pacific, 2014. Arch Virol 2015;epub:1-4.
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Footnote 16 Pan American Health Organization/World Health Organization. Epidemiological Update Neurological syndrome, congenital anomalies, and Zika virus infection; 2016. Available at: http://www.paho.org/hq/index.php?option=com_docman&task=doc_view&Itemid=270&gid=32879&lang=en. Accessed Feb 5, 2016.
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Footnote 17 European Centre for Disease Prevention and Control. Rapid risk assessment: Zika virus infection outbreak, French Polynesia; 2014. Available at: http://ecdc.europa.eu/en/publicatio...us-French-Polynesia-rapid-risk-assessment.pdf. Accessed Feb 5, 2016.
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Footnote 18 Bogoch II, Brady OJ, Kraemer MU, German M, Creatore MI, Kulkarni MA, et al. Anticipating the international spread of Zika virus from Brazil. Lancet 2016;387(10016):335-336.
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Footnote 19 Besnard M, Last?re S, Teissier A, Cao-Lormeau VM, Musso D. Evidence of perinatal transmission of Zika virus, French Polynesia, December 2013 and February 2014. Euro Surveill 2014;19(13):20751.
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Footnote 20 Oliveira Melo AS, Malinger G, Ximenes R, Szejnfeld PO, Alves Sampaio S, Bispo De Filippis AM. Zika virus intrauterine infection causes fetal brain abnormality and microcephaly: Tip of the iceberg? Ultrasound Obstet Gynecol 2016;47(1):6-7.
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Footnote 21 Musso D, Nhan T, Robin E, Roche C, Bierlaire D, Zisou K, et al. Potential for Zika virus transmission through blood transfusion demonstrated during an outbreak in French Polynesia, November 2013 to February 2014. Euro Surveill 2014;19(14):20761.
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Footnote 22 Musso D, Roche C, Robin E, Nhan T, Teissier A, Cao-Lormeau VM. Potential sexual transmission of Zika virus. Emerg Infect Dis 2015 Feb;21(2):359-361.
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Footnote 23 Foy BD, Kobylinski KC, Chilson Foy JL, Blitvich BJ, Travassos da Rosa A, Haddow AD, et al. Probable non-vector-borne transmission of Zika virus, Colorado, USA. Emerg Infect Dis 2011 May;17(5):880-882.
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Footnote 24 Dallas County Health and Human Services. DCHHS Reports First Zika Virus Case in Dallas County Acquired Through Sexual Transmission; 2016. Available at: http://www.dallascounty.org/departm...tCaseofZikaVirusThroughSexualTransmission.pdf. Accessed Feb 5, 2016.
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Footnote 25 Ioos S, Mallet H-, Leparc Goffart I, Gauthier V, Cardoso T, Herida M. Current Zika virus epidemiology and recent epidemics. Med Mal Infect 2014;44(7):302-307.
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Footnote 26 Villamil-G?mez WE, Gonz?lez-Camargo O, Rodriguez-Ayubi J, Zapata-Serpa D, Rodriguez-Morales AJ. Dengue, chikungunya and Zika co-infection in a patient from Colombia. J Infect Public Health 2015;epub.
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Footnote 27 Committee to Advise on Tropical Medicine and Travel (CATMAT). Canadian Recommendations for the Prevention and Treatment Of Malaria. 2014. Available at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/09vol35/35s1/index-eng.php. Accessed Feb 5, 2016.
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Footnote 28 Committee to Advise on Tropical Medicine and Travel (CATMAT). Fever in the returning international traveller initial assessment guidelines. Can Commun Dis 2011;37(ACS-2):1-24.
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Footnote 29 Shinohara K, Kutsuna S, Takasaki T, Moi ML, Ikeda M, Kotaki A, et al. Zika fever imported from Thailand to Japan, and diagnosed by PCR in the urines. J Trav Med 2016 Jan;23(1):1-3.
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Footnote 30 European Centre for Disease Prevention and Control. Zika virus infection: Factsheet for health professionals; 2015. Available at: http://ecdc.europa.eu/en/healthtopi...als/Pages/factsheet_health_professionals.aspx. Accessed Feb 5, 2016.
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Footnote 31 Oehler E, Watrin L, Larre P, Leparc-Goffart I, Last?re S, Valour F, et al. Zika virus infection complicated by guillain-barr? syndrome - case report, French Polynesia, December 2013. Euro Surveill 2014;19(9).
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Footnote 32 Balm MN, Lee CK, Lee HK, Chiu L, Koay ES, Tang JW. A diagnostic polymerase chain reaction assay for Zika virus. J Med Virol 2012;84(9):1501-1505.
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Footnote 33 Gourinat AC, O'Connor O, Calvez E, Goarant C, Dupont-Rouzeyrol M. Detection of Zika virus in urine. Emerg Infect Dis 2015;21(1):84-86.
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Footnote 34 Public Health Agency of Canada. Rapid Risk Assessment: The risk of Zika virus to Canadians; 2016. Available at: http://healthycanadians.gc.ca/publi...ctions/risks-zika-virus-risques/index-eng.php. Accessed Feb 5, 2016.
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Footnote 35 Pan American Health Organization/World Health Organization. Countries and territories with Zika autochthonous transmission in the Americas reported in 2015-2016; 2016. Available at: http://www.paho.org/hq/index.php?option=com_content&view=article&id=11603&Itemid=41696&lang=en. Accessed Feb 5, 2016.
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Footnote 36 Centers for Disease Control and Prevention (CDC). Updated diagnostic testing for Zika, chikungunya, and dengue viruses in US Public Health Laboratories; 2016. Available at: http://www.cdc.gov/zika/pdfs/denvchikvzikv-testing-algorithm.pdf. Accessed Feb 5, 2016.
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Footnote 37 Centers for Disease Control and Prevention (CDC). Clinical Evaluation & Disease; 2016. Available at: http://www.cdc.gov/zika/hc-providers/clinicalevaluation.html. Accessed Feb 5, 2016.
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Date modified: 2016-02-08
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