A war is being raged against the Aedes aegypti mosguito which is responsible for the transmission of the ZIKA fever, Dengue and Chikungunya in humans. The strategy against the mosquito involves manipulating the genetic profile of the insects so as to limiting the life-soan of its progeny.
A British company, called OXITEC, is a biotech company tasked with pioneering in environmentally friendly ways to control insect pests that spread disease and damage crops. The company has developed a strain of the mosquito referred to as OX513A.
The normal mosquito
After taking a blood meal, female Aedes aegypti mosquitoes produce on average 100 to 200 eggs per batch. The females can produce up to five batches of eggs during a lifetime. The female Aedes aegypti lays her eggs separately unlike most species. Not all eggs are laid at once, but they can be spread out over hours or days, depending on the availability of suitable substrates. Eggs will most often be placed at varying distances above the water line. The female mosquito will not lay the entire clutch at a single site, but rather spread out the eggs over several sites.
The insects goes through a complete metamorphosis (change) with an egg, larvae, pupae, and adult stage. The adult life span can range from two weeks to a month depending on environmental conditions. The life cycle of Aedes aegypti can be completed within one-and-a-half to three weeks.
The engineered mosquito
Oxitec uses advanced genetics to insert a self-limiting gene into its mosquitoes. The gene is passed on to the modified insect's offspring, so when Oxitec mosquitoes are released into the wild and mate with wild females their offspring inherit the self-limiting trait. The resulting offspring will die before reaching adulthood and the local mosquito population will decline.
The engineered male mosquito competes with normal males for normal females whose progeny will die before reaching adulthood. The progeny also compete with normal progeny for breeding spaces and resources before they die.
OX513A has regulatory approvals for import and contained testing in Brazil, Cayman Islands, France, India, Malaysia, Singapore, Thailand, USA and Vietnam. Open field trials have taken place in both Grand Cayman and Malaysia, and are currently also under-way in Brazil. In 2015 Brazil reported 3,530 cases of babies born with the condition called Microcephaly results in an infant with a head circumference below the average size, and other facial characteristics.