Reports and investigations from several countries strongly suggest that sexual transmission of the Zika virus is more common than previously assumed, said Margaret Chan, the Director-General from World Health Organization (WHO), on Tuesday.
"Since this emergency committee on Zika virus first met on February 1, substantial new clinical and epidemiological research has strengthened the association between Zika infection and the occurrence of fetal malformations and neurological disorders," Chan told reporters after WHO convened the second meeting of the Emergency Committee regarding clusters of microcephaly cases and other neurological disorders in some areas affected by Zika virus.
She noted local transmission has now been reported in 31 countries and territories in Latin America and the Caribbean and imported cases of Zika have been reported from every region in the world.
"Concerning the link with fetal malformations, the virus has been detected in amniotic fluid," Chan said, adding "evidence shows it can cross the placental barrier and infect the fetus. We can now conclude that Zika virus is neurotropic, preferentially affecting tissues in the brain and brain stem of the developing fetus."
In the America region, cases of dengue, which is carried by the same mosquito species as Zika, typically increase during the rainy season, which lasts from January to May. WHO expects to see more cases and further geographical spread.
"Aedes mosquito is responsible for transmitting dengue, chikungunya and Zika. Is there any potential (Zika) to spread like denge? we can not dismiss that, "Chan said.
Microcephaly is now only one of several documented birth abnormalities associated with Zika infection during pregnancy. To date, microcephaly has been documented in French Polynesia and Brazil. However, intense surveillance for fetal abnormalities is currently under way in countries like Colombia, where the outbreaks started later than in Brazil.
Nine countries are now reporting an increased incidence of Guillain-Barre syndrome or laboratory confirmation of a Zika virus infection among Guillain-Barre cases.
Based on the "alarming news", The Committee underscored the increasing strength of evidence showing a likely association between Zika infection and fetal malformations and neurological disorders. At the same time, the experts pinpointed the types of studies needed to establish a causal relationship, but stressed their view that strong public health actions should not wait for definitive scientific proof.
Therefore the Emergency Committee recommended that pregnant women should be advised not travel to areas of ongoing Zika virus outbreaks, pregnant women whose sexual partners live in or travel to areas with Zika virus outbreaks should ensure safe sexual practices or abstain from sex for the duration of their pregnancy.
The Committee also advised that the clusters of microcephaly cases and other neurological disorders continue to constitute a Public Health Emergency of International Concern (PHEIC), and that there is increasing evidence that there is a causal relationship with Zika virus.
