Monday, October 27, 2008

communicable diseases overview

from just a traveler's curiosity, while getting the vaccinations in order, one wonders what diseases torment the locals. the triple threat being malaria, yellow fever and typhoid. however from an aspiring/emerging epidemiologists's perspective, especially if you truly have a passion for such info, one naturally wants to know more. here is my quick middle-of the-night analysis.

factors contributing to epidemics:
1. climate change and El Nino have effects on vector-borne disease and rates of parasite and virus development in hosts in temp-dependent. aka watch out for those damn mosquitos! snails are also decent vectors. gross.

2. pervasive processes: urbanization, land and water resource developement, habitat fragmentation all increase pop density and bring wild mammals and birds into overlapping areas aka new diseases emerge. co-habitation doesn't always work!

3. high disturbance levels between two states of ecosystems. dont fuck around with chronotone disturbance!

4. migration rates, frequency and rapidity have huge affects on the spread and transmission AND (for all u geneticists) on the spread of genetic resistance to chemo agents.

5. globalization actually has adverse effects on infectious control. and we all thought globalizaiton is the greatest thing.

Now what are the most cool Brazil diseases?

1. HIV-who doesn't like AIDS? Unfortunately it reached epidemic proportions.

2. Chagas' disease (American trypanosomiasis). Named after Brazilian physician Carlos Chagas in 1909, caused my a parasite, transmitted by insect vectors called triatomine bug, that are found only in Americas. Not endemic in US, but I do remember admitting a kid w/this. Could lead to cardian and intestinal complications in the chronic phase.

3. Leprosy in high poverty areas. In 1996 on average a 100 new cases reported, and about half mil suffer from this now. This is just sad.

4. Bilharzia. First time I hear of this condition, so naturally I investigate. Caused by parasitic worms and become infected upon contact with contaminated freshwater snails that carry schistosomes. NOT found in US (thank goodness) but 200 mil around the world are infected. There goes snorkeling! This is when you love chlorine.

5. Rabies. I didn't get my shot because they're all out. The rabies virus is actually pretty awesome. ITs nonsegmented, with negative-stranded RNA genome, bullet shape. So what am I at risk for? If I encounter a mean bat, I would just shoot the sucker. But potentially I could suffer from encephalitis and outcome is almost always fatal. Transmission starts with mucous memberane penetration, and following primary infection, the virus enteres your CNS via retrograde axoplamic flow (basically through your neurons). This sounds horrid. I'll stop here.

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