The Zika virus was first identified in Uganda in 1947. Its ecological niche is significantly determined by changes in precipitation and temperature, making it more likely to be confined to tropical areas. However, rising global temperatures would allow for the disease vector (mosquito) to expand their range further north, allowing Zika to follow. This is how global warming and climate change could have multi-prong influence on ecosystem components especially the human beings.
Female mosquito (Aedes aegypti) is the predominant vector for Zika virus although common house mosquito (Culex) can also be blamed for the transmission. However, the true extent of the vectors is still unknown as Zika has been detected in many more species of Aedes as well as in Anopheles coustani, and Mansonia uniformis. The potential societal risk of Zika can be delimited by the distribution of mosquito species that transmit it. The global distribution of A. aegypti is, however, expanding due to trade and travel.
Monkeys were generally recognized as the primary host of the virus (like that of AIDS); only occasional transmission to humans being reported prior to 2007 when outbreaks occurred outside of Africa and spread to many countries of Latin America and the Caribbean including Barbados, Bolivia, Brazil, Colombia, the Dominican Republic, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Saint Martin, Suriname, and Venezuela.
Now that the threat of Zika virus is becoming serious, especially its appearance in the United States, efforts to combat have been intensified. North of Miami has recently been found to harbour mosquitos that may be responsible for the disease transmission. Earlier, the incidence was attributed mainly to person to person contact, the carrier coming from somewhere else. The virus is also reported to spread across South Florida and thus a big concern.
Disease situation becoming critical, solution is sought in the cause itself i.e. the Mosquito but following its genetic modification. In principle the approach is to eradicate mosquitoes but through genetic manipulations rather than using conventional approaches like those involving insecticides etc. The Aedes aegypti mosquitoes are genetically modified by Oxitec Ltd. in a way that the offspring die before they can reproduce, hence culmination of the race in due course of time. The requirement of course is to seek approval of the competent agencies for release of genetically modified organisms.
Oxitec being lucky, on August 5 the Food and Drug Administration (FDA) of the United States has announced the approval of a field test of GM mosquitoes to help combat the Zika virus. Earlier this year, FDA had given the go ahead or preliminary approval to Oxitec for conducting a field test and to deploy its OX513A mosquitoes in Key West. However, before conducting the test, Oxitec is required to obtain from the Florida Keys Mosquito Control District which in turn has to seek public opinion. Nevertheless, such field tests have already been conducted in Brazil (where two cases of Zika following blood transfusion were reported), the Cayman Islands, and Panama with a great degree of success; 90% reduction in local mosquito populations.
Like other genetic engineering approaches, deployment of genetically modified mosquitos is also expected to invite serious criticism although Oxitec claims that no practical risks are posed by the mosquitoes. However, for such risks to appear and be realized it takes years.
The fears notwithstanding, the biotechnology companies find it appropriate to go ahead with their plans although relatively risk free biological insect control approaches like Sterile Insect Technique (SIT) has also been demonstrated as promising to reduce insect populations. This method is based on the repeated release of sterile males who mate with the female as the normal males will but no offspring. Thus instead of killing the mosquitoes before they produce offspring in GM approach, SIT stops the process of reproduction per se (thus reducing the potential population), is biological, environment friendly, and more natural. The SIT has been very successful in controlling population of screw-worm fly (Cochlilomyia hominivorax) and fruit flies. It is not certain, however, if SIT can successfully be applied in case of mosquitoes although some successful studies have been reported even from 1970’s and 1980’s. The SIT can be resurrected in the wake of ever increasing role of mosquitoes in spreading viral disease.You can follow us on Facebook, Twitter, or Google+ for more updates. Otherwise fill in the subscription box above, or subscribe to our RSS Feed.