Zika virus was first isolated in the Zika forest of Uganda in 1947. Since then, it has remained mainly in Africa, with small and sporadic outbreaks in Asia. In 2007, a major epidemic was reported on the island of Yap (Micronesia), where nearly 75% of the population was infected. In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infection in Brazil. Since that time, cases have been reported from a total of 14 countries in the Americas. The World Health Organization has warned that the Zika virus is “spreading explosively” in the Americas, and that as many as four million people could be infected by the end of 2016.
Zika virus is transmitted to people primarily through the bite of an infected Aedes species mosquito. These are the same mosquitoes that spread dengue and chikungunya viruses. The yellow fever mosquito, Aedes aegypti, is found in tropical and subtropical regions throughout the world, and has experienced a resurgence into many areas where it was previously eliminated including parts of the United States and even the European periphery. The Asian tiger mosquito, Aedes albopictus, is also a capable vector and has spread from its Asian origin to five continents during the last three decades. It has now been detected in at least in 38 countries, and has become established in 28. Both species are aggressive daytime biters, and live in close association with human habitations.
Symptoms of Zika
The most common symptoms of Zika are fever, rash, joint pain, and conjunctivitis (red eyes). The illness is usually mild with symptoms lasting for several days to a week. Only about one in five people who are infected actually become sick, and for most people the infection causes no symptoms, and leads to no lasting harm. Mosquitoes become infected when they feed on a person already infected with the virus. Scientific concern is currently focused on the possible association of birth defects (microcephaly) to women who become infected while pregnant. Additionally, there are reports of a temporary form of paralysis (Guillain-Barré syndrome) that has been reported following exposure to the Zika virus.
How to fight against Zika
Reducing Zika virus infections is completely dependent on the control of mosquito vectors by eliminating larval habitat, or applying pesticides, and limiting person-mosquito contact through the use of repellents and improvements to housing (screening). Mosquito surveillance is a key component of any local integrated vector management program. The goal of mosquito-based surveillance is to quantify human risk by determining the presence and abundance of local vector populations. Biogents mosquito traps such as the BG-Sentinel are very effective in monitoring populations of Ae. aegypti and Ae. albopictus in a local area. For further information on controlling vectors of Zika virus see the CDC publication: Surveillance and Control of Aedes aegypti and Aedes albopictus >
Mosquito surveillance practices, such as the number and type of traps used and the frequency of sampling, depend largely on available funding, resources, and trained staff. However, in order to quickly identify and mitigate a mosquito-borne disease outbreak, establishing and maintaining a local vector surveillance program is critical.