08 March 2007

Mosquito Coast

It's coming, finally, as we'd feared. Tropical weather, and now a tropical disease! An epidemic outbreak of dengue fever has infected 16,000+ people in Paraguay (that's more than 1,000 km closer to the Equator than here) and killed hundreds. The first cases started appearing in the northeastern provinces of Argentina and soon Paraguayans coming to Argentina and Argentinians returning from a visit to Paraguay brought it to the central areas. There are more than 126 confirmed cases in the country, half of those in Buenos Aires City and around. In Rosario we have (I think, today) seven suspected cases and one confirmed.

Dengue is a disease similar to a strong flu, which causes headaches, muscular and joint aches, nausea, and fever. It's transmitted by Aedes aegypti, a species of mosquito. A. aegypti is not commonly found on this latitude, but I believe at least three of the cases in Buenos Aires are autoctonous, i.e. were contracted by human-mosquito-human transmission there, and not brought from Paraguay. The confirmed case in Rosario was infected during vacations in Buzios, Brazil (there are thousands of cases in southern Brazil as well).

Dengue has no specific treatment: people simply have to rest and keep drinking fluids, while the fever and the pain are treated with paracetamol-related drugs (paracetamol is known as acetaminophen in the U.S.), since the disease can have a haemorrhagic variant and you can't use the usual non-steroidal anti-inflammatory drugs (paracetamol is also much cheaper — but it can kill your liver). Patients must be isolated in order to prevent transmission, i.e. so that mosquitoes don't bite them and carry the disease elsewhere.

I haven't seen Aedes aegypti here, though I haven't been looking; they say it's noticeably different from the common local mosquitoes. There are a lot of those anyway. You have to consider that the Paraná River has a huge floodplain, full of shallow canals, marshes and other places with lots of vegetation and stagnant water, a perfect breeding ground. We've always had a lot of mosquitoes in the summer, but lately they're appearing in October and lasting until April or even May, and they're big and nasty.

Topping it off, the level of the Paraná is increasing, overflowing its banks. Rosario is not going to get flooded, but its beaches are already mostly gone. The river is forcing people in its islands to abandon them, and carrying aquatic plants that are left to rot in the shores. In Santa Fe City, 200 km north, 230 people have been evacuated, and some are worrying the population (unjustifiedly, according to the government) that there might be a flood like in 2003 (that one was not caused by the Paraná, but by the Salado River, which comes from the northwest of the country).

The mosquitoes are not going away. Pharmacies and supermarkets have noted that mosquito repellents have flown from the isles and the manufacturers are seemingly unable to cope with the demand. You can apply some cream or use an airborne repellent in your room at home, you can close off all openings with physical barriers, but you can't do anything while you're outside. Jogging along the coast the other day, my buddy and I observed that the moment we stopped to stretch, we were attacked by swarms of little bloodthirsty monsters. There are mosquitoes inside my office, and in the bus, and in the street while you're having a cup of coffee in a café.

The municipality has been spreading insecticide around, but it's not enough. Somebody in the radio today proposed we should breed dragonflies to eat the mosquitoes. Dragonflies, which are traditionally considered a sign that a rainstorm is about to come (at least that's what my parents passed down from my grandads), are repulsive when you see them up close, but they don't bite. I saw one flying inside the bus this morning as I went to work. I don't know if they actually feed on mosquitoes, but I know the weather tradition is grounded in reality, as it's been raining on and off for four of five days in a row.

So we have constant rain, mosquitoes and a tropical disease. What's next? Women wearing as little clothing as possible, pineapple drinks in the beach, a world-class carnival? You wish.


  1. Forget the dragonflies, and concentrate on bats - there much more efficient!

    Are insect screens on windows standard in Rosario? One thing that struck me about BsAs, is that new residential construction never has insect screens, even though the mosquito problem can be quite bad in summer.

    In northern California, such screens have been standard for years even though the mosquito problem is minor (mainly because there is so little precipitation during summer).

    The idea of constantly having to spray insecticide or be covered in repellant isn't too appealing ...



  2. I'm not sure if insect screens are provided by default in new homes (though they should). At home we have them almost everywhere. What I'm noticing is that, since the temperature dropped and the rains started, mosquitoes are comparatively scarce indoors and attack you when you get out.

    Ah yes, we do have bats. I've seen a lot of them lately. But they only work the night shift. :)

  3. Yes, get the dragonflies for the day shift.

    I have also noted, on the humorous side of things, my Argentine family is not very used to screened doors. The very first day they were installed my father in law walked right through one of them. I thought it would at least take a couple of days before that would happen.

    My wife thought I was crazy when I insisted that every window in our home have screens. She thanks me every once in a while for having insisted.

    In BsAs I have not seen too many screens on windows much less doors. Is there a technique for living with mosquitos that I just don´t know about?


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