Currently there are several confirmed cases of the Zika virus in Arkansas. The cases all involve individuals who contracted the disease while traveling in areas where the disease is prevalent, usually Latin American or Caribbean locales.
The virus can be carried by two related mosquitoes, Aedes aegypti and A. albopictus. Transmission of the disease occurs when a mosquito bites an infected individual and picks up the virus in the process. Then when that mosquito bites another uninfected person and inoculates them with the virus. Of the two mosquitoes, A. ablopictus is the lesser threat as it feeds on animals in addition to humans. On the other hand A. aegypti prefers humans and is therefore more likely to transmit the virus among humans.
Once contracted, an infected individual is capable of spreading the disease for several months, both via mosquito bites and also sexual contact. The virus has been isolated in the semen of infected men up to two months after acquiring the disease.
The range of A aegypti includes almost all of Arkansas, only the northeast corner near the boot heel of Missouri being outside the range. A aegypti is particularly problematic because it breeds rapidly and in amazingly small amounts of water. Eggs laid in a bottle cap’s worth of water mature to adults in as short as a weeks time. Also troublesome is that A aegypti is a daytime feeder when humans are more likely to be out and about.
The Zika virus causes a range of symptoms. A minor set of symptoms include rash, mild fever, joint pain and headache which may persist from a couple of days to a week or so. What has gotten the most attention of course is the teratogenic effect. If a pregnant woman gets infected, the virus can pass to the fetus and cause a condition know as microcephaly, an abnormally small head. The condition is severe and can result in seriously impaired brain function and premature death and.
Avoiding travel to the Caribbean or Latin America is no longer enough to be safe here in Arkansas. Because we have infected people and the transmitting mosquitoes, we are all at risk. So what is to be done? Obviously don’t get bitten by an infected mosquito, but that is easier said than done. The first line of defense would be to use an effective repellent. The gold standard, the agent which all others are compared to is DEET. Nothing is as effective nor lasts as long per application. The science is clear that all others have a weaker effect and don’t last as long.
Broad scale spraying of insecticides has been shown to reduce transmission rates, but in so doing kills off not only the target mosquitoes, but also any and all other insects. Many of these are not only desirable but a necessary part of human life. The FDA has recently approved an interesting strategy involving the use of gene modification to create a mosquito whose offspring can’t reproduce.
Most promising is an effective vaccine to prevent infection. This will have the least impact on the biosphere. No deaths on non-target insect species, nor any disruption of other organisms that rely to some degree on mosquitoes as part of their diet.