Zika: still wrapped in mystery

By Michael Cook

Editor’s note. The following is excerpted from a post at bioedge.org and is reprinted with permission.

zikavirus8A week of confusing information about the Zika virus epidemic, which the World Health Organization has described as a “Public Health Emergency of International Concern”.

In a report in the New England Journal of Medicine, Slovenian clinicians said that they had found the virus in the aborted remains of a baby with microcephaly whose mother had contracted the disease in Brazil. There have been a few other cases which also point to the virus as a direct cause of serious foetal abnormalities. …

However, there is also some evidence that the correlation of microcephaly with the Zika virus is a result of heightened awareness of the birth defect.

· A report from the Latin American Collaborative Study of Congenital Malformations suggests that the link between microcephaly and Zika may be due to “active search and over-diagnosis”.

· A report in The Lancet declared that “Although there is evidence of an increased number of cases of microcephaly in Brazil, … the number of suspected cases relied on a screening test that had very low specificity and therefore overestimated the actual number of cases by including mostly normal children with small heads.”

· An epidemiological report in the WHO’s Bulletin points out that a spike in microcephaly cases began in 2012, before reports of a Zika epidemic emerged in 2014. “If the ZIKV [Zika virus] were indeed introduced in Brazil at the World Cup in mid-2014, the outbreak of microcephaly would have preceded it. ZIKV has been identified in Africa over 50 years ago, and neither there nor in the outbreaks outside Africa, such an association with microcephaly has been reported.”

So there are still quite a few mysteries surrounding the virus. It is too early to panic or to resort to extreme measures like advising infected women to have abortions.