Question

Epidemiology

When dealing with infectious diseases, Epidemiologists have another triad: Agent, Host, Environment. So what does Environment actually mean, and with global climatic change, how does this affect it, if it does?

Answer 1

Here environment means the surrounding which help in multiplication of the pathogen. It includes not only the outer physical environment but also the condition in the hosts body that supports or inhibits the growth of the pathogen. As global warming is taking place there is a possibility that disease causing microbes/vectors will increase in number,specially in high altitude regions. For example , mosquitoes,the carrier of malarial parasite & dengue virus have reduced reproduction in cold environment but they will get suitable environment there if temperature is increased. On the other hand increased temperature in warmer regions may decrease the population of mosquitoes. Changed environment may change the immune system of the host giving rise to new strains of pathogen. Incident of heavy rain & accompanying flood has also become common nowadays. This may lead to increased incidence of water born disease like hepatitis B.