Wednesday, 17 March 2010

Fever in the forest - addendum

Lots of good questions! Thanks guys, it´s really nice to get feedback.

Steve, from what I know, Aedes aegypti can feed during the day, but they are more active around dusk. It´s complicated though, as Vitoria is being invaded by another species that can transmit Dengue, Aedes albopictus, and this is around all day. Worse still, it´s very nervous and flits away before finishing a good meal, so it has to bite lots of people.

I'm not sure that socks give you such immunity! Mosquitoes hunt you down by first following a trail of CO2, which is why some buzz around your face, and then smelling your sweat, which means exposed skin. Now, feet can be quite a potent source of er, odours, and the skin on the side is quite thin, hairless and easy to penetrate, so they make a good target, but not the only one. To diverge slightly, there was a famous experiment showing Limburger cheese as a good mosquito attractant, as the smell is similar to unwashed feet!

Bec, I know it sounds bizarre, but it might actually work! It is female mosquitoes that do the biting, and it´s only males that are released, after being sterilised. They mate with the females and produce infertile eggs (so you do get bitten now, just less in the future). This technique has been used to control insect pests like the Screw worm fly, or Mexican fruit flies, and in theory you don´t need any pesticides, but the problems are....
a) there is a high start up cost, you have to release lots of mossies, and sterilising them by radiation is fairly sophisticated
b) unless you live on an island, there will always be an influx of mosquitoes from outside. You just have to keep releasing indefinitely.
Still, it´s possible.

Mynah, I don´t know! They found antibodies, and virus gene sequence, but whether the bats, rodents etc would be a reservoir of infections for humans isn´t clear. In fact, what might be happening is that Dengue is evolving into Bat Dengue, Mouse Dengue etc, which wouldn´t be a problem (well, not for us).

Thanks again for the feedback!

1 comment:

Anonymous said...

Very nice collections of posters again! This really must be happening in Brazil! What is the government doing apart from this to face this problem? Do you have any idea?