Zika virus is name after the Zika Forest of Uganda, where it was first originated in 1947 during the course of a rigorous search for yellow fever virus under a collaborative project funded by the Rockefeller Foundation and British Government . The virus was derived from both a rhesus monkey and also from a group of Aedes africanus mosquitoes. The spread of Zika virus in the US was first corroborated in February, 2014, on Easter Island. In the following year, nearly 16 patients from the states of Bahia and Rio Grande do Nortei n Brazil were diagnosed as positive for the virus. Consequently, the virus has been detected in around 22 countries and territories identifiedfigure. Earlier, the Zia viral infection was linked to mild symptoms such as headache, pain in the joint, rash and conjunctivitis, but a potential connection between the viral infection during pregnancy and consequent birth abnormalities such as microcephaly was detected in November, 2015. x1ECDC. Microcephaly in Brazil potentially linked to the Zika virus epidemic. European Centre for Disease Prevention and Control, Stockholm; 2015See all References1 Approximately 4000 cases of anticipated Zica virus associated microcephaly have occurred in Brazil alone, with about 440 000 to 1·3 million people shown to be infected as yet. pregnancy until 2018 .
GENETIC MODIFICATION
Recent research has been focused on genetic modification of the A. aegypti mosquitoes and consequently making them resistant to the spread of Zika virus . The benefits of this genetic modification is that these genetically modified mosquitoes will control the spread of infection to people. The Britain based company Oxitec has targeted the genetically altered mosquito eggs with the aim of killing the offspring before they develop into full-fledged adults. The company has utilized genetics to control the reproduction of mosquitoes. Incorporation of the gene tTA that expresses a protein tTA. The genetic modification strategy termed as RIDL (the Release of Insects carrying Dominant Lethal genes) has been employed and involves the large scale rearing of A aegypti mosquitos that have been genetically altered to express a repressible lethal gene tTA . x4Phuc, HK, Andreasen, MH, Burton, RS et al. Late-acting dominant lethal genetic systems and mosquito control. BMC Biology. 2007; 5: 1–11CrossRef | PubMed | Scopus (155)See all References4During the process of their rearing, the mosquitoes are treated with a dietary supplement not occurring naturally (e.g., tetracycline), which inhibits the lethal gene activation. In this process, only male mosquitoes are released and these supersede the normal males to mate with normal females. The offsprings fail to progress into the adult stage, due to the lack of dietary additive in the wild. Releasing groups of altered mosquitoes and permitting their crossings with the normal A. aegypti may wipe out new progeny and decrease the mosquito species .These RIDL males have been demonstrated to possess very low fitness value. This technique has been demonstrated to accomplish about 95% decrease in the local mosquito species in the field release conducted in Bahia, Brazil .
x5Carvalho, DO, McKemey, AR, Garziera, L et al. Suppression of a field population of Aedes aegypti in Brazil by sustained release of transgenic male mosquitoes. PLoS Neglect Trop Dis. 2015; 9: e0003864CrossRef | Scopus (11)See all References5PROS OF THE STRATEGY
Considering the increasing resistance of mosquitos to the pesticides that are being used as a method to control them, genetic modification serves as a better alternative . The use of pesticides has been shown to be detrimental to human health and environment and proven to be sparingly effective. The outbreak of zika virus has necessitated the discovery of innovative options to inhibit the growth of A. aegypti mosquitoes. While some researchers are skeptical about the use of this strategy, supporters of this technique believe that it would be equivalent to exterminating invasive species.
Currently there are no treatment strategies or vaccines available to control the transmission and management of mosquitoes, while are solely dependent on the use of insecticides or annihilation of breeding sites . The insect resistance and environmental as well as health concerns related to the use of insecticides offers little optimism for the control of the disease. Vaccine development for zica is expected to many more years and hence use of novel approaches such as genetic modification serves as a more effective immediate strategy.
CONS OF THE STRATEGY
Despite optimism surrounding the use of genetic modification as a tool to control zica virus, some concerns pertaining the use of this method exist among the community of ecologists . They fear that the use of this method would eradicate the mosquito species that have some ecological benefits and produce an ecological hole. Some are of the opinion that their sheer count is a necessary connection in certain food webs, particularly in the artic tundra region, wherein, for a short period of time they expand in numbers and provide nutrition to the migratory birds . There is also a fear of removal of the A. aegypti species leading to a substitution with more dangerous vector species
Similar to the existing ethical concerns surrounding the use of genetically modified organisms, some scientists are apprehensive about the long-term repercussions of the use of this method . Considering that not much scientific information has been generated pertaining to the genetic modification of insects, there is always the concern of producing new unknown species of mosquitoes.
The other shortcoming of this genetic approach is that the genetic alteration is incapable of being perpetuated in progeny of the wild species .
Works Cited
Benedict, M Q & Wallace, H. Should Scientists Use Genetically Modified Insects to Fight Disease? 24 October 2011. http://www.scientificamerican.com/article/dengue-case-for-genetically-modified-mosquitoes/. 18 April 2016.
Howard, C R. "Aedes mosquitoes and Zika virus infection: an A to Z of emergence?" Emerging Microbes and Infections (2016): 5 (16).
Jeffries, M. Why don’t we wipe mosquitoes off the face of the Earth? 5 February 2016. http://www.sciencealert.com/why-don-t-we-wipe-mosquitoes-off-the-face-of-the-earth. 18 April 2016.
US FDA. 14 April 2016. http://www.fda.gov/%20EmergencyPreparedness/Counterterrorism/MedicalCountermeasures/MCMIssues/ucm485199.htm. 18 April 2016.
Yakob, L. "Zika virus outbreak in the Americas: the need for novel mosquito control methods." The Lancet Global Health (2016): 4 (3): 148 - 149. http://www.thelancet.com/journals/langlo/article/PIIS2214-109X(16)00048-6/fulltext.
