Nine out of ten people living in the depressed areas of Africa south of the Sahara still have nothing else to drink but meagre quantities of impure water, thus exposing themselves to serious diseases such as the appalling dracunculiasis.
This parasitic disease causes dreadful suffering and disability among the world's most deprived people. The disease reappears each year during the agricultural season, handicapping farmers, mothers and schoolchildren already weighed down by harsh living conditions and often existing just above survival level. Families affected by the disease experience great loss: their food stocks and savings gradually dwindle away, they are no longer able to participate in vaccination campaigns and the children's schooling increasingly suffers. Gradually worn down by penury, these underprivileged people find themselves trapped in a vicious circle of poverty and disease.
Dracunculiasis is a disease caused by the parasitic worm Dracunculus medinensis or "Guinea worm". This worm is the largest of the tissue parasite affecting human. The adult female, which carries about 3 million embryos, can measure 600 to 800 mm in length and 2 mm in diameter. The parasite migrates through the victim's subcutaneous tissues causing severe pain especially when it occurs in the joints. The worm eventually emerges (from the feet in 90% of the cases), causing an intensely painful oedema, a blister and the an ulcer accompanied by fever, nausea and vomiting.
Infected persons try to relieve the burning sensation by immersing the infected part of their body in local water sources, usually ponds water. This also induce a contraction of the female worm at the base of the ulcer causing the sudden expulsion of hundreds of thousands of first stage larvae into the water. They move actively in the water and can live for a few days in water.
For further development, they need to be ingested by suitable species of voracious predatory crustacean, Cyclops or water fleas which measure 1 - 2 mm and widely abundant worldwide. In the cyclops, larvae develop to infective third-stage in 14 days at 26°C.
When a person drink contaminated water from ponds or shallow open wells, the cyclops is dissolved by the gastric acid of the stomach and the larvae are released and migrate through the intestinal wall. After 100 days, the male and female meet and mate. The male become encapsulated and die in the tissues while the female move down the muscle planes. After about one year of the infection, the female worm with the uterus filled with larvae, emerges usually from the feet repeating the life cycle.
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An emerged Guinea worm is being pulled out from a small girl in Tamale, Ghana |
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A Guinea worm emerging form a foot of a person in Sudan |
No drugs are currently available to prevent or heal this parasitic disease - the only disease exclusively associated with unsafe drinking water. Dracunculiasis is, however, extremely easy to combat and should no longer be prevalent.
Dracunculiasis is rarely fatal. Frequently, however, the patient remain sick for several months, mainly because:
- Several worms are expelled successfully,
- The migration and emergence of the worms occur in sensitive parts of the body, e.g. the sole of the feet,
- Serious secondary bacterial infection frequently sets in subsequent to the accidental rupture of the worm.
Temporary disability can leave 58% unable to leave their beds for a month during and after the emergence of the worm, as found by a longitudinal study in Nigeria. This usually occurs during the peak agricultural activities and labour is in a great demand, this can effect the nutritional status of their children. In Sudan, households where more than half the adult members had suffered from Guinea worm in one year, their under 6 year children were three times as likely to be malnourished, as indicated by wasting. For that reason, considering only the benefit of reducing incidence, the WB estimated 29% economic rate of return for the global Guinea worm campaign which has cost US$ 90 millions todate. However, this is only part of the cost as Guinea worm cause other negative social and educational impact such as preventing infected people from engaging into social activities and prohibit children from attending schools.
The epidemiology of the diseases is determined largely by the use of open water sources such as ponds and sometimes shallow or step wells. Man-made ponds such as hafirs in Sudan and small scale dams in West Africa are the main source of transmission. The disease is seasonal occurring with two broad patterns found in endemic areas of Africa depending upon climatic factors. In the Sahelian zone, transmission generally occurs in the rainy season (May to August). In the humid savanna and forst zone, the peak occurs in the dry season (September to January). However, there are local variations in these patterns. Other risk factors are mobility and infection the previous year.
Dracunculiasis is a vulnerable disease: man alone is responsible for maintaining its fragile transmission cycle. It is therefore possible to permanently curtail transmission by applying simple measures. Some elementary steps include:
- systematic filtering of drinking water derived from ponds and shallow unprotected wells or from surface water. Finely-meshed cloth or, better still, a filter made from a 0.15 mm nylon mesh, is all that is needed to filter out the cyclops from the drinking water.
- the construction of copings around well ######### or the installation of boreholes with handpumps. This would prevent not only dracunculiasis but also diarrhoeal diseases.
If these measures are accepted and then administrated by village communities, the ultimate goal will be achieved: the eradication of dracunculiasis .
Kostawi
فيس بوك
تويتر
انستقرام
يوتيوب
بنتيريست