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Tuesday, February 17, 2009

Kiss of Death

In light of the recent events, Darwin’s 200th birthday (Feb.12th) and Valentine’s Day, I thought I’d shed some light on a on a little critter called the Kissing Bug.

The Kissing Bug (Panstrongylus geniculatus) is a member of the Assassin Bug family Reduviidae. These insects get their name from the location of their bite, which are usually the lips. Kissing bugs feed mostly on the blood of vertebrates, but the ones that feed on human blood can carry serious disease. In South American countries, these little critters are the main vectors for a parasite called Trypanosoma cruzi which causes Chagas Disease.

An interesting fact about T. cruzi is that it is not passed from saliva to blood like many other disease spreading vectors (i.e. mosquitoes), but rather through the Kissing Bugs feces. These parasites crawl their way into the wound made from the bite. Soon after the parasite enters the wound, the site of infection becomes enlarged and swollen. Other symptoms include: fever, fatigue, body aches, headache, rash, loss of appetite, diarrhea, and vomiting. You may think that this is as bad as it gets, but unfortunately this disease can lay dormant inside you for years and is incurable. When this nasty disease finally does reemerge, the symptoms are much worse and usually cause severe heart damage and malformation of the intestines.

Though the Kissing Bug really doesn’t have any attachment to Valentine’s Day, I just thought its name was appropriate for the occasion. So now you may be wondering what the Kissing Bug and T. cruzi have to do with Darwin? Well unfortunately for Darwin, while on his voyage on the H.M.S Beagle it was thought that he was bitten by a Kissing Bug, which may have been cause of his debilitating disease later in life. Darwin wrote an account of this bite:

"We crossed the Luxan, which is a river of considerable size, though its course towards the sea-coast is very imperfectly known: it is even doubtful whether, in passing over the plains, it is not evaporated and lost. We slept in the village of Luxan, which is a small place surrounded by gardens, and forms the most southern cultivated district in the Province of Mendoza; it is five leagues south of the capital. At night I experienced an attack (for it deserves no less a name) of the Benchuca, a species of Reduvius, the great black bug of the Pampas. It is most disgusting to feel soft wingless insects, about an inch long, crawling over one's body. Before sucking they are quite thin, but afterwards they become round and bloated with blood, and in this state are easily crushed. One which I caught at Iquique, (for they are found in Chile and Peru,) was very empty. When placed on a table, and though surrounded by people, if a finger was presented, the bold insect would immediately protrude its sucker, make a charge, and if allowed, draw blood. No pain was caused by the wound. It was curious to watch its body during the act of sucking, as in less than ten minutes it changed from being as flat as a wafer to a globular form. This one feast, for which the benchuca was indebted to one of the officers, kept it fat during four whole months; but, after the first fortnight, it was quite ready to have another suck."- Charles Darwin, March 25, 1835

As I said before, there is no cure for this disease so prevention is important. So if you even have the urge to do some traveling around South America, be sure to take a mosquito net when camping outdoors. Insecticides can only do so much to control their numbers and prevent the Kiss of Death.

1 comment:

  1. I remember hearing about Darwin and the kissing bug in almost every single class where the discussion of evolution ever came up. However, I've never seen Darwin's comments about the bugs before. Including that was a neat aspect of the post.

    I also think it's quite convenient how the topic related both to Darwin and to Valentine's Day.

    The post is well-written and I think the only other thing you could probably do is to explain more specifically what you want readers to gather from the blood cell picture.