Pathfinder
Editor, Senior Moderator
ZIKA VIRUS
MICROCEPHALY
AND GUILLAIN-BARR? SYNDROME
SITUATION REPORT
19 FEBRUARY 2016
SUMMARY
Between 1 January 2007 and 17 February 2016, a total of 48 countries and territories
reported local (autochthonous) transmission of Zika virus, including those where the
outbreak is now over, and including countries and territories that provided indirect
evidence of local transmission. Among the 48 countries and territories, Aruba and
Bonaire are the latest to report autochthonous transmission of Zika virus.
Geographical distribution of Zika virus has steadily broadened since the virus was first
detected in the Americas in 2015. Zika transmission has been reported in 28
countries/territories. The discovery of Zika virus in additional countries within the
geographical range of competent mosquito vectors ? especially Aedes aegypti? is
considered likely.
Six countries/territories (Brazil, French Polynesia, El Salvador, Venezuela, Colombia and
Suriname) have reported an increase in the incidence of cases of microcephaly and/or
Guillain-Barr? syndrome (GBS) following a Zika virus outbreak. Microcephaly has so far
been reported only from Brazil and French Polynesia. Puerto Rico and Martinique have
also reported cases of GBS associated with Zika virus infection, but without evidence of
an overall increase in the incidence of GBS.
Evidence that neurological disorders, including microcephaly and GBS, are linked to Zika
virus infection remains circumstantial, but a growing body of clinical and epidemiological
data points towards a causal role for Zika virus.
The global prevention and control strategy launched by WHO as a Strategic Response
Framework (SRF)1
encompasses surveillance, response activities, and research. Following
consultation with partners and taking changes in caseload into account, the SRF will be
updated at the end of March 2016 to reflect epidemiological evidence coming to light
and the evolving division of roles and responsibilities for tackling this emergency.
I. SURVEILLANCE
Incidence of Zika virus
From 1 January 2007 to 17 February 2016, Zika virus transmission was documented in a
total of 48 countries and territories (Fig. 1 and Fig. 2). This includes 36 countries which
reported local transmission between 2015 and 2016, six countries with indirect evidence
of viral circulation, five countries with reported terminated outbreaks and one country
with a locally acquired case but without vector-borne transmission (Table 1). Among the
48 countries and territories, Aruba and Bonaire are the latest to report autochthonous
transmission.
In late 2014, Brazil detected a cluster of cases of febrile rash in the Northeast Region of
the country. The diagnosis of Zika virus infection was confirmed (RT-PCR test for viral
RNA2
) in May 2015. Due to the size of the outbreak, Brazil ceased counting cases of Zika
virus. The Brazilian Ministry of Health estimates that between 497 593 and 1 482
7013
cases of Zika virus infection have occurred since the outbreak began.
Recently the virus has spread rapidly in the region. By 11 February 2016, 28
countries/territories in the Americas had reported local transmission of the virus. The
reported rate of its spread across South and Central America accelerated from October
2015 onwards (Fig. 1)
From October 2015 to 6 February 2016, Colombia reported 31 555 cases, including 1504
laboratory confirmed cases. The number of cases reported each week accelerated
between December 2015 and February 2016 (Fig. 3).
From October 2015 to 31 January 2016 Cabo Verde reported 7258 suspected cases of
Zika virus disease.
Incidence of microcephaly
From November 2015 to 13 February 2016, a total of 5280 cases of microcephaly and/or
central nervous system (CNS) malformation were reported by Brazil, including 108
deaths. This contrasts with the period from 2001 to 2014, when an average of 163
microcephaly cases were recorded nationwide per year.
Investigations have been concluded for 1345 cases of microcephaly and/or CNS
malformation in Brazil. Of these cases, 837 were discarded, 508 were confirmed and
3935 remain under investigation5
. Of the 462 cases confirmed on 6 February, 421 had
radiological findings compatible with a congenital infection and 41 had laboratory
confirmation of Zika virus infection6
.
70 of the 108 deaths that occurred after childbirth or during pregnancy (through
miscarriage or stillbirth) among the 5280 cases of microcephaly and/or CNS
malformation remain under investigation. Eleven others have been discarded and 27
have been confirmed as microcephaly and/or CNS malformation. A case of microcephaly
associated with Zika virus infection was reported by the Hawaii State Department of
Health on 8 January 2016 and another such case was reported by Slovenian public
health professionals on 10 February 2016. Both mothers spent time in Brazil in early
pregnancy and experienced symptoms compatible with Zika virus disease during that
period. Neither mother had laboratory testing for Zika virus infection at that time. A Zika
virus infection was laboratory confirmed in the baby born with microcephaly in Hawaii7
,
and after the autopsy of the fetus (mandatory in all cases of termination of pregnancy)
in Slovenia8
. No autochthonous transmission of Zika virus has been reported in Hawaii or
Slovenia.
French Polynesia reported an increase in the number of CNS malformations in children
born between March 2014 and May 2015. In this period 18 cases were reported,
including nine microcephaly cases, compared to the national average of 0 to 2 cases per
year.
Zika virus is not proven to be a cause of the reported increase of microcephaly in Brazil.
However, given the temporal and geographical associations between Zika infections and
GBS, and in the absence of a compelling alternative hypothesis, a causal role for Zika
virus is a strong possibility that requires further investigation.
Incidence of Guillain-Barr? syndrome
In the context of Zika virus outbreaks, Brazil, Colombia, El Salvador, Suriname and
Venezuela have reported an increase of Guillain-Barr? syndrome (GBS). This syndrome
was also detected during the 2013-2014 Zika virus outbreak in French Polynesia.
In July 2015, Brazil reported 42 GBS cases in the state of Bahia, among them 26 (62%)
with a history of symptoms consistent with Zika virus infection. In November 2015, seven
patients presenting neurological syndromes including GBS were laboratory confirmed for
Zika virus infection. In 2015, a total of 1708 cases of GBS were registered nationwide,
representing a 19% average increase from the previous year (1439 cases of GBS), though
not all states reported an increase in incidence. Further investigation is ongoing.
In February 2016, Colombia reported an increase in cases of GBS, which appears to have
begun during 2015 (Fig. 3). Over the past seven years (2009-2015) Colombia has
registered an average of 223 GBS cases per year. During the five weeks from midDecember
2015 to late January 2016, 86 GBS cases were reported. If Zika virus is also a
cause of microcephaly then microcephaly cases in Colombia should be expected in the
course of 2016.
From 1 December 2015 to 9 January 2016, 118 GBS cases were recorded in El Salvador,
including 5 deaths, while the average number of GBS cases per year prior to 2015 cases
was 169. Of the 22 patients whose information was available, 12 (54%) presented with
febrile rash illness consistent with Zika virus infection in the 15 days prior to the onset of
symptoms. To date, none of the GBS cases reported in El Salvador have been laboratory
tested for Zika virus infection or other causes.
On 29 January 2016, Suriname reported increased incidence of GBS in 2015. While
Suriname registered on average four cases of GBS per year prior to 2015, 10 GBS cases
were reported in 2015 and three in the first three weeks of 2016. Zika virus infection was
confirmed in two of the 10 GBS cases reported in 2015.
On 2 February 2016, Venezuela reported an increase in GBS since the second week of
January 2016. From 1 January to 31 January 2016, 252 GBS cases with a spatiotemporal
association to Zika virus. Cases were recorded in most parts of the country; 66 of these
were detected in the state of Zulia, mainly in Maracaibo municipality. Preliminary
analysis of GBS cases in Zulia indicating a clinical history consistent with Zika virus
infection was observed in the days prior to onset of neurological symptoms in 76% of
GBS cases. Zika virus infection was confirmed by RT-PCR in three patients with GBS.
In French Polynesia, 42 GBS cases were identified during the 2013-2014 Zika outbreak,
88% of which presented an illness compatible with Zika virus infection. Retrospective
sero-neutralisation tests revealed that all 42 cases suffered dengue and Zika virus
infection.
As with microcephaly, Zika virus is not proven to be a cause of increased GBS incidence in
Brazil, Colombia, El Salvador, Suriname or Venezuela. However, a causal role for Zika
virus is a strong possibility. Confounding factors include the contemporary circulation of
dengue and chikungunya in the Americas, which are transmitted by the same species of
mosquito. Further investigations are needed to identify the potential role of other factors
(including infections) known to be associated, or potentially associated, with GBS.
...
http://apps.who.int/iris/bitstream/10665/204454/1/zikasitrep_19Feb2016_eng.pdf?ua=1
http://www.who.int/emergencies/zika-virus/situation-report/19-february-2016/en/
MICROCEPHALY
AND GUILLAIN-BARR? SYNDROME
SITUATION REPORT
19 FEBRUARY 2016
SUMMARY
Between 1 January 2007 and 17 February 2016, a total of 48 countries and territories
reported local (autochthonous) transmission of Zika virus, including those where the
outbreak is now over, and including countries and territories that provided indirect
evidence of local transmission. Among the 48 countries and territories, Aruba and
Bonaire are the latest to report autochthonous transmission of Zika virus.
Geographical distribution of Zika virus has steadily broadened since the virus was first
detected in the Americas in 2015. Zika transmission has been reported in 28
countries/territories. The discovery of Zika virus in additional countries within the
geographical range of competent mosquito vectors ? especially Aedes aegypti? is
considered likely.
Six countries/territories (Brazil, French Polynesia, El Salvador, Venezuela, Colombia and
Suriname) have reported an increase in the incidence of cases of microcephaly and/or
Guillain-Barr? syndrome (GBS) following a Zika virus outbreak. Microcephaly has so far
been reported only from Brazil and French Polynesia. Puerto Rico and Martinique have
also reported cases of GBS associated with Zika virus infection, but without evidence of
an overall increase in the incidence of GBS.
Evidence that neurological disorders, including microcephaly and GBS, are linked to Zika
virus infection remains circumstantial, but a growing body of clinical and epidemiological
data points towards a causal role for Zika virus.
The global prevention and control strategy launched by WHO as a Strategic Response
Framework (SRF)1
encompasses surveillance, response activities, and research. Following
consultation with partners and taking changes in caseload into account, the SRF will be
updated at the end of March 2016 to reflect epidemiological evidence coming to light
and the evolving division of roles and responsibilities for tackling this emergency.
I. SURVEILLANCE
Incidence of Zika virus
From 1 January 2007 to 17 February 2016, Zika virus transmission was documented in a
total of 48 countries and territories (Fig. 1 and Fig. 2). This includes 36 countries which
reported local transmission between 2015 and 2016, six countries with indirect evidence
of viral circulation, five countries with reported terminated outbreaks and one country
with a locally acquired case but without vector-borne transmission (Table 1). Among the
48 countries and territories, Aruba and Bonaire are the latest to report autochthonous
transmission.
In late 2014, Brazil detected a cluster of cases of febrile rash in the Northeast Region of
the country. The diagnosis of Zika virus infection was confirmed (RT-PCR test for viral
RNA2
) in May 2015. Due to the size of the outbreak, Brazil ceased counting cases of Zika
virus. The Brazilian Ministry of Health estimates that between 497 593 and 1 482
7013
cases of Zika virus infection have occurred since the outbreak began.
Recently the virus has spread rapidly in the region. By 11 February 2016, 28
countries/territories in the Americas had reported local transmission of the virus. The
reported rate of its spread across South and Central America accelerated from October
2015 onwards (Fig. 1)
From October 2015 to 6 February 2016, Colombia reported 31 555 cases, including 1504
laboratory confirmed cases. The number of cases reported each week accelerated
between December 2015 and February 2016 (Fig. 3).
From October 2015 to 31 January 2016 Cabo Verde reported 7258 suspected cases of
Zika virus disease.
Incidence of microcephaly
From November 2015 to 13 February 2016, a total of 5280 cases of microcephaly and/or
central nervous system (CNS) malformation were reported by Brazil, including 108
deaths. This contrasts with the period from 2001 to 2014, when an average of 163
microcephaly cases were recorded nationwide per year.
Investigations have been concluded for 1345 cases of microcephaly and/or CNS
malformation in Brazil. Of these cases, 837 were discarded, 508 were confirmed and
3935 remain under investigation5
. Of the 462 cases confirmed on 6 February, 421 had
radiological findings compatible with a congenital infection and 41 had laboratory
confirmation of Zika virus infection6
.
70 of the 108 deaths that occurred after childbirth or during pregnancy (through
miscarriage or stillbirth) among the 5280 cases of microcephaly and/or CNS
malformation remain under investigation. Eleven others have been discarded and 27
have been confirmed as microcephaly and/or CNS malformation. A case of microcephaly
associated with Zika virus infection was reported by the Hawaii State Department of
Health on 8 January 2016 and another such case was reported by Slovenian public
health professionals on 10 February 2016. Both mothers spent time in Brazil in early
pregnancy and experienced symptoms compatible with Zika virus disease during that
period. Neither mother had laboratory testing for Zika virus infection at that time. A Zika
virus infection was laboratory confirmed in the baby born with microcephaly in Hawaii7
,
and after the autopsy of the fetus (mandatory in all cases of termination of pregnancy)
in Slovenia8
. No autochthonous transmission of Zika virus has been reported in Hawaii or
Slovenia.
French Polynesia reported an increase in the number of CNS malformations in children
born between March 2014 and May 2015. In this period 18 cases were reported,
including nine microcephaly cases, compared to the national average of 0 to 2 cases per
year.
Zika virus is not proven to be a cause of the reported increase of microcephaly in Brazil.
However, given the temporal and geographical associations between Zika infections and
GBS, and in the absence of a compelling alternative hypothesis, a causal role for Zika
virus is a strong possibility that requires further investigation.
Incidence of Guillain-Barr? syndrome
In the context of Zika virus outbreaks, Brazil, Colombia, El Salvador, Suriname and
Venezuela have reported an increase of Guillain-Barr? syndrome (GBS). This syndrome
was also detected during the 2013-2014 Zika virus outbreak in French Polynesia.
In July 2015, Brazil reported 42 GBS cases in the state of Bahia, among them 26 (62%)
with a history of symptoms consistent with Zika virus infection. In November 2015, seven
patients presenting neurological syndromes including GBS were laboratory confirmed for
Zika virus infection. In 2015, a total of 1708 cases of GBS were registered nationwide,
representing a 19% average increase from the previous year (1439 cases of GBS), though
not all states reported an increase in incidence. Further investigation is ongoing.
In February 2016, Colombia reported an increase in cases of GBS, which appears to have
begun during 2015 (Fig. 3). Over the past seven years (2009-2015) Colombia has
registered an average of 223 GBS cases per year. During the five weeks from midDecember
2015 to late January 2016, 86 GBS cases were reported. If Zika virus is also a
cause of microcephaly then microcephaly cases in Colombia should be expected in the
course of 2016.
From 1 December 2015 to 9 January 2016, 118 GBS cases were recorded in El Salvador,
including 5 deaths, while the average number of GBS cases per year prior to 2015 cases
was 169. Of the 22 patients whose information was available, 12 (54%) presented with
febrile rash illness consistent with Zika virus infection in the 15 days prior to the onset of
symptoms. To date, none of the GBS cases reported in El Salvador have been laboratory
tested for Zika virus infection or other causes.
On 29 January 2016, Suriname reported increased incidence of GBS in 2015. While
Suriname registered on average four cases of GBS per year prior to 2015, 10 GBS cases
were reported in 2015 and three in the first three weeks of 2016. Zika virus infection was
confirmed in two of the 10 GBS cases reported in 2015.
On 2 February 2016, Venezuela reported an increase in GBS since the second week of
January 2016. From 1 January to 31 January 2016, 252 GBS cases with a spatiotemporal
association to Zika virus. Cases were recorded in most parts of the country; 66 of these
were detected in the state of Zulia, mainly in Maracaibo municipality. Preliminary
analysis of GBS cases in Zulia indicating a clinical history consistent with Zika virus
infection was observed in the days prior to onset of neurological symptoms in 76% of
GBS cases. Zika virus infection was confirmed by RT-PCR in three patients with GBS.
In French Polynesia, 42 GBS cases were identified during the 2013-2014 Zika outbreak,
88% of which presented an illness compatible with Zika virus infection. Retrospective
sero-neutralisation tests revealed that all 42 cases suffered dengue and Zika virus
infection.
As with microcephaly, Zika virus is not proven to be a cause of increased GBS incidence in
Brazil, Colombia, El Salvador, Suriname or Venezuela. However, a causal role for Zika
virus is a strong possibility. Confounding factors include the contemporary circulation of
dengue and chikungunya in the Americas, which are transmitted by the same species of
mosquito. Further investigations are needed to identify the potential role of other factors
(including infections) known to be associated, or potentially associated, with GBS.
...
http://apps.who.int/iris/bitstream/10665/204454/1/zikasitrep_19Feb2016_eng.pdf?ua=1
http://www.who.int/emergencies/zika-virus/situation-report/19-february-2016/en/