The Zika virus has hit Barbados. It won’t be long before it is in T&T. It rarely causes any problems but the painful memory of Chikungunya lingers strong enough to cause anxiety at the thought of another mosquito borne disease.
The symptoms are mild and up to ¾ of infected people will never know they have it. There is some concern that it may cause a birth defect called microcephaly, but this is not yet proven. As a precaution, pregnant women are told to make sure they are not bitten.
It is just one of a long line of Old World mosquito borne diseases to enter the Americas, ever since the Atlantic slave trade introduced the Anopheles and Aedes aegypti mosquitos from West Africa to the West Indies.
These are the mosquitos that host malaria for the Anopheles and yellow fever, dengue, chikungunya and now zika, in the case of the Aedes aegypti.
Conditions for mosquitos were made perfect when the forests were razed for sugar plantations. In an out of balance eco system mosquito populations would explode. It’s no surprise that in our part of the world we humans are the ultimate cause of one of our own greatest annoyances.
The economic cost is huge. During the chikungunya epidemic of 2014 some island economies creaked under the strain of the bend-over-in-pain disease. Jamaica lost US$60 million and 13 million man-hours to the disease. If T&T was affected proportionally we could guestimate that the economic loss here was US$120 million and 6.5 million man-hours lost.
Researchers have found that in the years after El Niño cycles mosquito populations get out of hand in the Caribbean. El Niño in the West Indies usually means drought. Mosquitos stop reproducing but their predators die too. When the rains return the mosquitos come back with nothing to stop them.
One thing that always gives me relief in the jungle is the fact that there are so few mosquitos around. I’m not talking about the twilight zone, the hour around dusk, when mosquitos can swam. No, I'm talking about the other 22 or 23 hours a day when you don't get bitten by mosquitos. In an intact ecosystem, mosquitos don't get out of control.
We’ve been trying to eliminate mosquitos for decades by inflicting chemical warfare on them. We have not fared well. Fogging is done with an insecticide called Malathion, which is mixed with diesel and sprayed in neighbourhoods. It isn't much of a solution.
We've used that for decades, and guess what, mosquito populations are out of control in urban areas. One reason may well be that the chemicals are not very selective, and they kill both the mosquitos and their predators.
The mosquitos wait for a post-fogging rain to breed unchecked and come back with explosive force.
I usually sit at home in a stifled room because opening the windows means getting swarmed by mosquitos. I have been a fool though. In my grandfather's house all the windows were covered in mosquito netting. The nets were fixed in to frames that could be slid in to place when needed.
Not many houses have that again. I suspect that burglar proofing and mosquito netting may be a difficult combination, but with proper design these two negatives of Trinbagonian life can be kept outside. And what about insect vector control? I haven't seen them by my house for years. We used to get regular visits.
They would leave telltale yellow cards, usually by the electricity meter, with the date and signature of the inspecting officer. They would do things like make you remove tyres or plant pots with water, or clean drains and gutters where mosquitos breed.
Mosquitos must be good for something. Lots of mosquitos are pollinators. It is just a few species that want our blood. Mosquito larvae serve as food for fish, frogs, lizards and spiders. Bats eat mosquitos too, but unfortunately it seems that they prefer moths. It’s hard to think of something positive about mosquitos, or to identify a role that they fulfill that can’t be carried out by another species.
Our challenge is to keep them away from us while not indiscriminately killing off everything around them. The answer may be in a genetically modified mosquito that mates with female mosquitos to produce sterile offspring. Tests are being done with that in Key West and in Brazil.
In the meantime, get those mosquito nets installed.