Friday, June 6, 2008

climate change and vector borne diseases in the tropics


A vector-borne disease is one in which the pathogenic microorganism is transmitted from an infected individual to another individual by an arthropod or other agent, sometimes with other animals serving as intermediary hosts. The transmission depends upon the attributes and requirements of at least three different living organisms: the pathologic agent, either a virus, protozoa, bacteria, or helminth (worm); the vector, which are commonly arthropods such as ticks or mosquitoes(image) ; and the human host. In addition, intermediary hosts such as domesticated and/or wild animals often serve as a reservoir for the pathogen until susceptible human populations are exposed.

An increased incidence of vector-borne diseases is to be expected as a result of climate change. The projected changes in climate and climate variability will have a profound impact on the ecology of vector populations. In order to estimate the extent to which such events might occur, the effects of climate change on the distribution and epidemiology of malaria and dengue are to be scientifically evaluated. There is a clear indication of the change in risk of malaria and dengue in the coming 80 years. '. All climate scenarios an increase of malaria and dengue transmission potential as climate changes. Also a change of the seasonality of these diseases is to be expected. The field study in western Kenya underlines the potential changes that may occur under predicted climate change scenario's. Increased temperatures lead to shorter mosquito development times and more mosquito generations per year. Should this be accompanied by more events of intense rainfall, malaria in the Kano plains will increase, and the people of the Kericho hills will experience more episodes of malaria epidemics than at present. Such events can, as we have seen, alarming effects on the malaria incidence in mostly African children.

Nearly half of the world's population is infected by vector-borne diseases, resulting in high morbidity and mortality. The distribution of the incidence of vector-borne diseases is grossly disproportionate, with the overwhelming impact in developing countries located in tropical and subtropical areas.

Weather affects vector population dynamics and disease transmission, with temperature and humidity considered key variables. Only recently have researchers attempted to predict how climate change might affect the distribution of vector-borne diseases. A comprehensive model should consider both the direct impacts (such as changes in temperature or rainfall) and indirect impacts (such as changes in hydrology or agriculture) of global warming on the agent, vector, intermediary host, and the human host. The response of each element of the disease process to climate change may have ramifications for the others.

THE MOSQUITO thrives well in the tropics causing Malaria and other life threatening conditions.
So let us work towards a better world with minimal environmental degradation because this can lead to extinction of life and the universe in totality.