Climate Change a Culprit in Spread of Disease

Part 1 in the series: Is climate change affecting tourism through spread of disease?

The relationship between the now notorious Swine Flu and climate change may not be obvious. Yet this pandemic, the result of several novel mutations of the H1NI influenza subtypes, is known to worsen and spread due to climatic variations. This is just one of the many examples where our health could inevitably be linked to climate change. This correlation between noticeable climate change and health is still an issue under debate, but has been corroborated by various scientific sources.

A report from the Wildlife Conservation Society lists a dozen deadly diseases like Avian Influenza, Plague, Tuberculosis and lesser known ones like Ebola and Lyme, whose spread and growth can be attributed to climate change. For example, a shift in the geographic distribution of ticks could spread Lyme, while migratory birds carrying these viruses could spread it to new regions. Change in wind direction, storms and certain regions of the world becoming warmer than they used to be, facilitate accelerated transmission.

Rising temperatures also have a worsening effect on diseases like cholera. Though cholera may not seem like a fatal disease to most readers of this article, it is interesting to note that there have been many outbreaks and even some pandemics associated with cholera, especially in developing countries. Poor sanitation facilities, inadequate number of potable water sources, and lack of medical care can make a choleric outbreak catastrophic. Survival of parasites and rodents is aided by heavy rains and increasing temperatures, a common trend in sub-tropical and other climate regions experiencing increased intensity and frequency of floods, typhoons, storms, droughts and the like, at the cost of our very own survival.

Experts in vector-borne diseases believe climate change might affect the life cycle of mosquitoes, enabling the spread which could further mutate into complex and unforeseen diseases. Below a simple example is cited of a disease prevalent in most sub-tropical regions which reflects how survival of our very own race is at stake (The same can be extended to Chikungunya and a host of other vector borne diseases):

For malaria transmission to occur, a mosquito must take a blood meal from someone with malaria, incubate the parasite, then bite an uninfected person and inject the parasite. Warmer temperatures speed up the maturation of the malarial parasites inside the mosquitoes. At 20°C (68°F), for example, Plasmodium falciparum malarial protozoa take 26 days to incubate; but, at 25°C (77°F), the parasites develop in half the time. Anopheline mosquitoes that can transmit malaria live only several weeks. Thus warmer temperatures permit parasites to mature in time for the mosquito to pass it on to someone previously uninfected.

It is things like this that remind us how connected two seemingly different issues like climate change and global health really are, because life systems are, in fact, very complicated. As Dr. Steven E. Sanderson, President and CEO of the Wildlife Conservation Society says,

“The term ‘climate change’ conjures images of melting ice caps and rising sea levels that threaten coastal cities and nations. But just as important is how increasing temperatures and fluctuating precipitation levels will change the distribution of dangerous pathogens. The health of wild animals is tightly linked to the ecosystems in which they live and influenced by the environment surrounding them. Even minor disturbances can have far reaching consequences on what diseases they might encounter and transmit as climate changes.”