Diseases Associated with Poor Drainage System

1) Schistosomiasis:

In countries where schistosomiasis is endemic, poorly drained urban areas present ample opportunities for transmission of disease. Contamination of standing water with the faeces of infected persons (or for one form of the disease, with their urine)

enables the schistosomiasis the microscopic parasite that cause this infection to reach the small aquatic snails in whose bodies they multiply from every infected snail, thousands of shistosomes emerge and swim in the water. Local residents because infected when they enter the water and the shistosomes penetrate their skin.

Schistosornaisis be thought of as a rural disease, but it is often no less prevalent in urban areas where drainage is lacking. Some of the species of the snail host thrive and breed rapidly in heavily polluted stagnant water which often accumulates there. Moreover, a single infected person in an area can cause sufficient contamination to infect very large numbers of the people living in his or her crowded neighbourhood because even a small number of snails, once infected, can produce many thousands of schistosomes over a long period of time. Caircross, (1986).

2) Malaria

Another important group of disease related to poor drainage is transmitted by mosquitoes. Deferent species of mosquito and each chooses different bodies of water in w which to breed in flooded areas, some in drains themselves if they are blocked by rubbish or vegetation or are laid unevenly so that there is standing water in them.

Malaria is the best known of mosquito-borne infections, and is transmitted by anopheles species, many of which bite animal as well as humans. Transmission can be particularly intense in urban areas where there are relatively few animals to divert the victor species of mosquito from human blood meals. Anopheline mosquito do not usually breed in heavily polluted water, but can multiply in swaps, pools puddles and also in streams and storm water canals in which there is standing water. Anophelines mosquito breeding in poorly drained areas can transmit malaria to adjacent parts of the town. A particular danger in a city is the significant amount of international travel to and from it, which increases the risk of importation of new and possibly drug resistant strains of the malaria parasite.

3) Filariasis:

There is particularly an urban problem of bancroftian filariasis, which appear to be the original vector of transmission in urban areas by the culex pipiens groups which generally multiply in heavily polluted bodies of water transmission of the disease is a relatively inefficient processes, so that many years of exposure to intense night time mosquito biting are needed for the average case to develop.

Nevertheless, more than 80 million people in the developing world are infected. In many countries such as India, it is especially prevalent in urban areas. Filariasis transmission by culex pipiens mosquito is now common in Asia, is occurring in cities on the eastern coasts of Africa and South America, and may soon begin in the large poorly drained urban areas of West Africa where both the disease and the vector already exist.

Drainage construction is an effective mosquito control measures. It is cheaper than application of insecticides and does not have to be repeated regularly, in many cases, it cost more than a year’s supply of insecticides, it can have no detrimental effect on the environment, on the contrary, it constitutes an environmental improvement. Moreover, the danger of mosquito developing resistance, as they have been known to do to insecticides does to apply.

References

Cairncross, S. (1986): “Urban Drainage Developing Countries”