Microcephaly is a nuerological disorder, which results due to the abnormal development of the brain inside the womb, or the brain not growing at the expected rate after birth. As a result the heads of infants are signigicantly smaller than their counterparts, which can mean loss of brain tissue, smaller cerebellums, calcium deposits and unusually smooth brains. It can be caused due to genetic conditions (such as Down Syndrome), malnourished, diabetic or alcoholic pregnant women or certain types of infections. Although not always, microcephaly can mean significant brain damage.

The disorder has been around for a long time and in Pakistan is probably the reason for the small heads of children so often seen at Shah Dola's shrine.

Now there is a new contender threatening to spread this disease at a rate so alarming that the WHO has termed it a global health emergency this week. This is the Zika Virus , which is transmitted by the Aedes mosquito. The virus was first isolated in Uganda in 1947 in the Zika forest, from where it gets its name.  Generally, the virus occurs around the equatorial belt between Africa and Asia and causes a curable mild sickness called the Zika fever. Since 2014 it has started spreading , first crossing the Pacific Ocean towards the east and from there it has entered Central and South America. The outbreak of Zika Virus and its suspected link to microcephaly was first detected in Brazil in May 2015. And since then it has spread to over 20 countries.

More and more cases of microcephaly are being reported in Brazil; although it must be kept in mind that a direct link between the two has not yet been established by researchers. Even so, the evidence for a causal link is growing, according to the Director General of WHO, Dr. Margret Chan. The Organization estimates that 4 million people could be affected by the end of 2016.

Earlier, it seemed that because it was a mosquito borne virus, it may not reach areas with effective mosquito control programmes. However, on February 3, news came out from Texas, USA that it had been transmitted sexually by someone who had travelled to Venezuela. This aspect obviously has increased the likelihood of a pandemic, many many fold, as people return from traveling in Central and South America.

And now Africa and Asia can expect to be hit by it too. In fact, experts are now saying that there may have been surges in microcephaly when the virus reached Asia from Africa in the last century, however, there were no effective techniques to diagnose it.

Overpopulated Asia, with its slums and high number of mosquitoes is very vulnerable to this disease. Both Thailand and Indonesia have already confirmed a case each. The main problem is that Zika is carried by the same mosquito that carries dengue, already widespread in Asia. Dengue has spread extensively across countries over the last several years and it can come as no surprise that Zika can as well.

A WHO spokeman Eloi Yao however has said that while it may spread to Asia, the risks are "low". Pakistan has described the risk as "non-significant" but is monitoring the situation.

There are no vaccines and the only prevention is to control mosquito populations and preventing mosquito bites in "at risk" individuals, primarily pregnant women.

Asian countries such as Pakistan, while low risk for now, cannot afford to be complacent. More efforts need to be made to control this mosquito in order to curtail the spread of both Dengue and Zika . And more information needs to be provided to people as to how to protect themselves from mosquito bites, as well as other means of transmission, especially when traveling.