Zika fever is a mosquito-borne viral disease caused by Zika virus (ZIKV), consisting of mild fever, rash (mostly maculo-papular), headaches, arthralgia, myalgia, asthenia, and non-purulent conjunctivitis, occurring about two to seven days after the mosquito vector bite. One out of four people may develop symptoms, but in those who are affected the disease is usually mild with symptoms that can last between two and seven days. Its clinical manifestation is often similar to dengue, also a mosquito-borne illness.
(article from July 23, 2014)
Oxitec’s solution is an advancement of SIT, which involves the insertion of a lethal gene into male mosquitoes that prevents them from being able to successfully reproduce. Although the insects are not truly sterile, they can be considered sterile because they die before reaching sexual maturity. Released “sterile” males will therefore seek out females to mate with, competing with wild males, and the resultant progeny will contain the lethal gene and therefore die before they can mate. If a sufficient number of mosquitoes are released, the females will be more likely to find a “sterile” male, and a substantial drop in population can be achieved in a remarkably short period. The flight range of dengue mosquitoes is also around only 200 yards and they’re restricted to urban areas, making it easy to control populations with this technique as “zones” of release can be established to ensure sufficient area coverage.
The sophisticated yet simple system also involves the insertion of a fluorescent tag called DsRed that allows careful monitoring of mosquito populations after initial release; a “track and trace” system, says Hadyn Parry, CEO of Oxitec. This means population control can be maintained over time through repeat release, which will be guided by monitoring fluorescent mosquito levels. The technique doesn’t necessarily eliminate mosquito populations; rather it keeps them at such a low levels that disease transmission no longer occurs.
From the PAHO site:
Countries and territories with Zika autochthonous transmission reported in the Americas Region. Epidemiological Week (EW) 17 of 2015 to EW 3 of 2016:
Barbados, Bolivia, Brazil, Colombia, Dominican Republic, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Saint Martin, Suriname, Venezuela.