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WHO expands Zika sexual transmission advice
Filed Under:
Zika
Lisa Schnirring | News Editor | CIDRAP News
| Sep 06, 2016
The World Health Organization (WHO) today expanded its recommendations for preventing the sexual spread of Zika virus, as new research findings in mice suggest that the eyes can harbor the virus, which could be shed through tears.
In other key developments, US lawmakers returned to Washington, DC, today after a 7-week summer break and have 4 weeks to act on a Zika funding bill before they break again in advance of the November elections, while Florida today reported seven more locally acquired Zika infections.
In international developments, Singapore's Zika total continues to grow rapidly, with 86 more cases reported in the past few days.
Sexual transmission caution expands to 6 months
The WHO said its new interim recommendations for preventing the sexual spread of Zika virus reflect the latest scientific evidence.
Since the group's previous update in June, researchers have reported that evidence of the virus can persist in semen for as long as 6 months, longer than previously thought. Other teams recently documented a case of sexual spread from an asymptomatic man to his female partner and sexual spread of the virus from a woman to a man.
Among the main changes for sexually active men and women in active transmission areas is that they should be accurately counseled and offered a full range of contraceptive methods so they can make an informed choice on whether and when to become pregnant to avoid the Zika-linked adverse pregnancy and fetal outcomes.
In areas where the virus is not spreading locally, the WHO now recommends that both women and men who are returning from Zika-affected areas abstain or practice safe sex for 6 months, even if they're not trying to conceive and regardless of symptoms.
Earlier guidance had suggested that asymptomatic men returning from active transmission areas abstain or practice safe sex for at least 8 weeks.
Benjamin Haynes, a spokesman for the US Centers for Disease Control and Prevention (CDC), said the CDC is aware of the WHO's guidance update, adding that it is reviewing the latest scientific information, which continues to change rapidly. He said the CDC will update its guidance when the review is complete.
Persistence of the virus in eyes
If the findings in mice published today in Cell Reports translate to humans, tears could be the latest on a growing list of body fluids known to transmit Zika virus.
In the new study, researchers based at Washington University School of Medicine experimentally infected adult mice by injecting the virus under their skin, then assessed the effect on the eyes of fetal, newborn, and adult mice.
Some effects of Zika are already known. About a third of babies born with congenital Zika infections have eye problems such as retinal damage or blindness, and in infected adults, conjunctivitis is a common symptom.
After the researchers infected the mice, they found live virus in the eye 7 days later. Though the findings confirm that the Zika virus can reach the eye, scientists still aren't sure how it arrives. It could cross the blood-retina bloodstream, follow the optic nerve from the brain to the eye, or reach the eye through some other route, the team wrote.
Tests found Zika RNA in mouse tears, but not infectious virus when tested 28 days later.
Jonathan Miner, MD, PhD, lead author and professor of medicine, said in a university press release that lack of live virus in mouse tears doesn't rule out that Zika couldn't be infectious in human tears. "There could be a window of time when tears are highly infectious and people are coming in contact with it and able to spread it," he said.
Researchers say they're exploring a host of different transmission routes, because Zika virus seems to be spreading unusually fast?more rapidly than just mosquito transmission alone would dictate.
Michael Diamond, MD, PhD, professor of medicine and one of the study's senior authors, in the press release called Zika's spread explosive. "Sexual transmission is probably not playing a major role, but it could be some other bodily fluid?saliva, or urine or tears."
The team said the eye experiments may yield other useful benefits, such as another noninvasive route for testing and an animal model for testing Zika drug candidates.
Florida reports 7 more local cases
The seven new local Zika cases announced by the Florida Department of Health (Florida Health) today include six cases linked to the Miami Beach active transmission area, which were confirmed on Sep 2 when state offices were closed due to Hurricane Hermine. The seventh new case is associated with a new investigation in Miami-Dade County, Florida Health said in a daily update.
Florida now has 56 local Zika cases. It added 1 more travel-linked case, lifting that number to 577.
As Singapore total climbs, tests show no New World link
Over the weekend and through today, Singapore's health ministry announced 86 more local Zika cases and said in its Sep 3 update that genetic sequencing suggests that the Zika strain fueling its outbreak is from the Asian lineage and evolved from a strain already in Southeast Asia, which seemingly suggests that virus spread there isn't an extension of transmission from the Americas.
Singapore's Ministry of Health (MOH) doesn't keep a running total of cases, but based on a composite of its daily updates, the country has about 275 cases over the last 11 days.
In confirming 17 new cases today, the MOH said 10 were linked to a previously identified cluster. One of the new cases and an earlier announced case may be linked to a potential new cluster, according to the report. The six other new cases have no known links to any of the earlier noted clusters.
Genetic sequencing test results, noted in the MOH's Sep 3 statement, were based on samples from two patients in the same cluster. It said the virus wasn't imported from South America and that the research team will release more details shortly.
Third trimester infection, local Zika in the Philippines
See also:
Sep 6 WHO updated interim sexual transmission guidance
Sep 6 Cell Reports abstract
Sep 6 Washington University School of Medicine press release
Sep 6 Florida Health daily Zika update
Sep 6 Singapore MOH daily Zika statement
Sep 3 Singapore MOH daily Zika statement
WHO expands Zika sexual transmission advice
Filed Under:
Zika
Lisa Schnirring | News Editor | CIDRAP News
| Sep 06, 2016
The World Health Organization (WHO) today expanded its recommendations for preventing the sexual spread of Zika virus, as new research findings in mice suggest that the eyes can harbor the virus, which could be shed through tears.
In other key developments, US lawmakers returned to Washington, DC, today after a 7-week summer break and have 4 weeks to act on a Zika funding bill before they break again in advance of the November elections, while Florida today reported seven more locally acquired Zika infections.
In international developments, Singapore's Zika total continues to grow rapidly, with 86 more cases reported in the past few days.
Sexual transmission caution expands to 6 months
The WHO said its new interim recommendations for preventing the sexual spread of Zika virus reflect the latest scientific evidence.
Since the group's previous update in June, researchers have reported that evidence of the virus can persist in semen for as long as 6 months, longer than previously thought. Other teams recently documented a case of sexual spread from an asymptomatic man to his female partner and sexual spread of the virus from a woman to a man.
Among the main changes for sexually active men and women in active transmission areas is that they should be accurately counseled and offered a full range of contraceptive methods so they can make an informed choice on whether and when to become pregnant to avoid the Zika-linked adverse pregnancy and fetal outcomes.
In areas where the virus is not spreading locally, the WHO now recommends that both women and men who are returning from Zika-affected areas abstain or practice safe sex for 6 months, even if they're not trying to conceive and regardless of symptoms.
Earlier guidance had suggested that asymptomatic men returning from active transmission areas abstain or practice safe sex for at least 8 weeks.
Benjamin Haynes, a spokesman for the US Centers for Disease Control and Prevention (CDC), said the CDC is aware of the WHO's guidance update, adding that it is reviewing the latest scientific information, which continues to change rapidly. He said the CDC will update its guidance when the review is complete.
Persistence of the virus in eyes
If the findings in mice published today in Cell Reports translate to humans, tears could be the latest on a growing list of body fluids known to transmit Zika virus.
In the new study, researchers based at Washington University School of Medicine experimentally infected adult mice by injecting the virus under their skin, then assessed the effect on the eyes of fetal, newborn, and adult mice.
Some effects of Zika are already known. About a third of babies born with congenital Zika infections have eye problems such as retinal damage or blindness, and in infected adults, conjunctivitis is a common symptom.
After the researchers infected the mice, they found live virus in the eye 7 days later. Though the findings confirm that the Zika virus can reach the eye, scientists still aren't sure how it arrives. It could cross the blood-retina bloodstream, follow the optic nerve from the brain to the eye, or reach the eye through some other route, the team wrote.
Tests found Zika RNA in mouse tears, but not infectious virus when tested 28 days later.
Jonathan Miner, MD, PhD, lead author and professor of medicine, said in a university press release that lack of live virus in mouse tears doesn't rule out that Zika couldn't be infectious in human tears. "There could be a window of time when tears are highly infectious and people are coming in contact with it and able to spread it," he said.
Researchers say they're exploring a host of different transmission routes, because Zika virus seems to be spreading unusually fast?more rapidly than just mosquito transmission alone would dictate.
Michael Diamond, MD, PhD, professor of medicine and one of the study's senior authors, in the press release called Zika's spread explosive. "Sexual transmission is probably not playing a major role, but it could be some other bodily fluid?saliva, or urine or tears."
The team said the eye experiments may yield other useful benefits, such as another noninvasive route for testing and an animal model for testing Zika drug candidates.
Florida reports 7 more local cases
The seven new local Zika cases announced by the Florida Department of Health (Florida Health) today include six cases linked to the Miami Beach active transmission area, which were confirmed on Sep 2 when state offices were closed due to Hurricane Hermine. The seventh new case is associated with a new investigation in Miami-Dade County, Florida Health said in a daily update.
Florida now has 56 local Zika cases. It added 1 more travel-linked case, lifting that number to 577.
As Singapore total climbs, tests show no New World link
Over the weekend and through today, Singapore's health ministry announced 86 more local Zika cases and said in its Sep 3 update that genetic sequencing suggests that the Zika strain fueling its outbreak is from the Asian lineage and evolved from a strain already in Southeast Asia, which seemingly suggests that virus spread there isn't an extension of transmission from the Americas.
Singapore's Ministry of Health (MOH) doesn't keep a running total of cases, but based on a composite of its daily updates, the country has about 275 cases over the last 11 days.
In confirming 17 new cases today, the MOH said 10 were linked to a previously identified cluster. One of the new cases and an earlier announced case may be linked to a potential new cluster, according to the report. The six other new cases have no known links to any of the earlier noted clusters.
Genetic sequencing test results, noted in the MOH's Sep 3 statement, were based on samples from two patients in the same cluster. It said the virus wasn't imported from South America and that the research team will release more details shortly.
Third trimester infection, local Zika in the Philippines
- Brazilian researchers today reported the first known evidence of brain injury in babies infected with Zika virus during mothers' third pregnancy trimester. They described two cases in the Clinical Infectious Diseases. Both babies were born with no microcephaly or other obvious findings, but imaging of the newborns identified subependymal cysts and lenticulostriate vasculopathy, which have been seen with other congenital viral infections. At 3 months and 1 month of age, the babies' neurologic systems are so far developing normally. The researchers noted that follow-up will determine if the lesions have any impact on neurodevelopment.
- Health officials in the Philippines yesterday reported the nation's first local Zika case of 2016, involving a 45-year-old women who is not pregnant and has no history of travel to an affected area, according to an official statement. Health officials said they are increasing mosquito control efforts and are asking people to take precautions, such as emptying mosquito breeding sites. The Philippines has reported sporadic local cases in the past and is on the WHO's list of countries experiencing possible endemic transmission.
See also:
Sep 6 WHO updated interim sexual transmission guidance
Sep 6 Cell Reports abstract
Sep 6 Washington University School of Medicine press release
Sep 6 Florida Health daily Zika update
Sep 6 Singapore MOH daily Zika statement
Sep 3 Singapore MOH daily Zika statement