Focus on prevention

Timely action needed to curb the spread of zika virus

The outbreak of dreaded zika virus in Jaipur may have so far been confined to its epicentre alone, but the risk of its spreading to other areas seems quite high for several reasons. For one, this is already the third episode of zika eruption in India in less than two years. Besides, the carrier of this virus is the same day-biting Aedes aegypti mosquito that spreads dengue, chikungunya, and other vector-transmitted diseases and is present in hordes in most parts of the country. Moreover, unlike in the past when the virus was detected in infected patients only, this time the scientists have been able to trace it even in the mosquitoes, indicating the danger of its dispersal. In Jaipur itself, the number of zika-positive cases has swelled to over 80 in just around three weeks, defying all efforts to contain it. No doubt, Aedes mosquitoes normally do not move beyond 400 to 500 metres, but the same is not true of the zika-infected human beings. They can serve as zika carriers even during the virus’ incubation period prior to the appearance of the symptoms. So, treating the Jaipur zika outbreak as an isolated case and limiting the control measures to that region alone would be imprudent.

Mercifully, deaths because of the zika virus are rare. The patients typically recover in two to seven days. But this virus is dreaded more than other vector-borne infections because of its effects on pregnant women. Striking directly at the foetus and deforming the brain of the unborn child, it results in the birth of children with mental and physical disabilities. It can, at times, cause miscarriage or premature delivery. Some adult patients can also face neurological complications. Most other symptoms of zika virus are the same as those of dengue and other types of viral flu — high fever, headache, muscle and joint pain, skin rashes and conjunctivitis-like eye troubles. 
 

In the absence of any vaccine or specific drugs to cure zika (except generic treatment with paracetamol), protection from mosquito bite and mosquito control are the only ways to combat this menace. This requires breaking the breeding cycle of the mosquitoes by destroying their eggs and larvae rather than just killing the adult mosquitoes as is usually done through fogging. A nationwide mosquito control programme of the kind that had, in the past, helped in nearly eradicating malaria is needed once again. Though the option of using the versatile, cheap and highly effective pesticide, DDT, is no longer available thanks to the ill-advised ban on it, other suitable chemical and biological means, such as larvae-eating fish and mosquito predators, would need to be deployed to check mosquito multiplication. 

Significantly, a well-crafted National Vector-Borne Diseases Control Programme already exists in the government files. But it is resurrected only during disease epidemics. If it is implemented on a regular basis on the lines of the polio control programme, it can help avert zika and also scourges such as malaria and Japanese encephalitis. However, since Aedes mosquitoes breed even in small collections of fresh water in and around homes, schools and work sites, door-to-door surveys to monitor the presence of larvae and suitable action against the defaulters are absolutely essential. The gains from spending resources on taming disease-dispensing vectors would far outweigh the cost of dealing with recurrent disease outbreaks.