Global warming and killer diseases

I searched the archives, and came up empty-handed. I’m thinking that with the big melts happening in polar regions and places like Kilmanjaro, there could very well be something frozen in that ice that will be very happy to wake up and see this big population of humans set out like one big banquet. Something that will make Ebola and Hanta look like your annoying but harmless old aunties. Anyone know if this has been studied, or if places like the CDC are making preparations for such an event? :eek: Color me paranoid…

Rather than releasing nefarious lifeforms frozen in the ice a la The Thing, the more serious threat from killer diseases and global warming is that changes in the climate could allow disease vectors (i.e., mosquitoes and such-like) to expand their ranges into areas where they weren’t previously found, carrying malaria and dengue fever and so on with them.

I wouldn’t be too worried about anything popping out of the ice. Though I haven’t seen any papers on this, the chances of something thawing out at the same moment that an organism it is able to infect happens to be passing by seem rather miniscule.

Generally, the basic formulae governing infectious disease spread follow the general pattern of

dI/dt = BSI - aI - bI - vI
(dI/dt) = rate of infection or spread
I is number of infected individuals
S is number of susceptible individuals
B is transmissibility
a is death rate from disease
b is death rate independant of disease
v is recovery rate (assume immunity after recovery)

so if duration of disease “D” = 1/(a + b + v)
then threshold population = 1/(BD)

The problem being experienced with outbreaks such as ebola and the various hanta viruses is due to increased exposure and increased effective population.

The increased exposure could result from changes in the ranges of vectors such as MEBuckner mentioned. More specifically, with ebola is is hypothesized to have resulted from the increase in the bush meat trade, and with hantaviruses is due to squalid living conditions (outbreak in New Mexico [Texas?]) and researchers crawling into woodrat middens and the like (not that I’ve ever done anything like that).

The increased effective population is the real killer. Back in the day, ebola could have been occurring just as frequently as now. Only just the hunting party or small tribe or whatever would have bit the dust. Back in the day, the isolation of small population centers kept down effective population, keeping down disease. Now someone hops the trail to the next town, and we get an outbreak. Luckily, there still isn’t any good way to get from deepest africa to NYC in a damn hurry, but once we find something with an incubation period long enough to allow the next National Geographic fellow to pick it up and bring it back to D.C…ouch. Basically, ebola’s virulence (“a” above) is what’s keeping it from being more of a problem than it is.

(who doesn’t like hearing “oh, did I mention they just found a new strain of hantavirus?” just before going into a cave after a woodrat midden)

I’m not sure about the melting icecap aspect, but there are several sources on emerging infective diseases:

CDC’s Preventing Emerging Infective Diseases and their journal Emerging Infectious Diseases

Popular sources such as Laurie Garrett’s books: The Coming Plague and Betrayal of Trust.

ProMed,a listserve for reporting emerging diseases.