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)
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).
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.
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.
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.
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.
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.
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”
Countries”
