Volume 9 Number 2 August 1995
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CholeraAn acute disease of the gastrointestinal tract is caused by the contamination of water/drink and food by the strains of vibrio cholera. Different serotype named Inaba, Ogawa and Hikojima have been identified. The biotype Eltor serotype Ogawa) has become widespread in the last four decades and appears to be displacing the classical v. cholera from most areas. Early travellers had reported epidemics of cholera in Ethiopia. People threatened by cholera were reported to have fled away from their areas and those from suspected foci were prohibited to travel into cholera free areas (5). Several thousand deaths occurred in eastern, central and southern Ethiopia in the 1970 outbreak. In 1973 another epidemic struck the country and several hundred people died. It is reported that occurrence of some cholera epidemics were not announced by the Ethio- pian government due to fear that agricultural export might suffer (5). According to a report of the Epidemiology Department of the Ministry of Health of Ethiopia among severe cases about 50% die. With treatment the death rates may come down up to 1% (8). Hand-washing, proper waste disposal, personal hygiene and making drinking water safe, health education, preparedness and surveillance at times and after outbreaks are recognized as important measures in the control of the disease (8). Yellow feverYellow fever is said to be endemic in Africa including in Ethiopia. The major clinical syndrome associated with Yellow fever is haemorrhagic fever. The earliest survey carried out in nine provinces of Ethiopia found no Yellow Fever. However, Ethiopia is still in the list of countries in Africa with Yellow Fever, based on the various entomological studies confirming the presence of the probable vectors (Aedes Species). The first cases of Yellow fever were reported in 1959 from Beninshangul (Asosa) district, and may have originated from Western Wellega. There were 100 deaths. The epidemic was confined to the wet rainy season and in the lowlands between Asosa and Kurmuk towns. The second and more serious epidemic started in the lower Omo Valley near Dime in Gamu Gofa at the end of 1960 .This epidemic lasted for 18 months and affected one million people. Most cases were reported from Gamo Gofa, Kefa and Sidamao and few cases from the Didessa river valley in Wellega. All age groups and both sexes were affected. The total morbidity was around 100,000 people and mortality rates ranging from 30 -85% were reported. The classical clinical forms of yellow fever during this epidemic were - sudden onset, acute in early cases and lasting seven days in fatal cases, black vomit, renal symptoms with albuminuria, later fulminating forms with intense general symptoms and high mortality. The last yellow fever epidemic was reported in 1966 near Lake Abaya and around the town of Akobo. Here, there were 2,200 cases and 450 deaths, and it was believed to have been introduced by monkeys into Lake Abaya and these became endemic in subsequent years. The entire south-western regions of the country can be divided into two zones: an epidemic zone along the Sudan border from Lake Tukana to the Blue Nile, and an endemic zone covering large parts of Gamo Gofa, parts of Kaffa and parts of Wolayita. 'Enset' and 'Taro' play an important role in the propagation on yellow fever, because these plantations serve as living and breeding places for the Aedes Simpsoni mosquito -the principal vectors of yellow fever in Ethiopia. Recent assessment indicates that there have been no officially reported and confirmed cases of yellow fever since the last epidemic of 1966. Studies in 1970, 1972, 1975-76 showed a wide distribution of virus activity as manifested by relatively high antibody titers in humans and isolation of the virus from animals and arthropods in formerly epidemic areas. It is generally recommended that, considering the ecology of Western Ethiopia, the abundance of vectors and wild reservoir hosts, extensive population movements, and recent acceleration in landscape change (deforestation, settlement patterns and water resource developments), careful epidemiological surveillance is required if yellow fever is to remain under control. In addition to human behavioural and environmental changes, the appearance of new, stable mutant viruses may facilitate the spread of arbovirus diseases. Louse-bome typhus (epidemic type) This is a common cause of Acute Febrile Illness (AFI) seen throughout the country and especially in the highlands. In Ethiopia it is commonly known as "tessebo", and the first epidemic was reported in 1866, in army Camps and prisons. Afterwards, cases seen were reported by different Ethiopian as well as expatriate health workers. In 1960s and 70s most cases of louse-borne typhus in the world were reported from Ethiopia, Rwanda and Burundi. Between 7 ,000 -16,000 cases were reported annually to the MOH of Ethiopia during 1952- 1980. Fewer cases (2,000 - 4,500) were reported between 1987 -1990. More than 90% of cases reported are from Central and Northern Ethiopia. Most affected areas include Tigray, Gojjam, Gondar and Shewa provinces (now nanled Regions 1, 3 and parts of 4) respectively. During the last phase of the civil war in 1990- 91, serious outbreaks of louse-borne typhus occurred in army Campus relief shelters, and rural villages. Recent data from Addis Ababa suggest that epidemic typhus is not very common among the rural population ( 19) . Numerous local epidemics have been reported since 1940s from Ethiopian prison, refugee camps and relief shelters and rural villages. Some of the risk factors for the acquisition of typhus are: having body lice, infrequently washing cloths, older age, and rural dwelling. Some of the habits of inhabitants of Ethiopian highlands favouring the survival of body and head lice are: they wash their cloths and bath less frequently, wear more clothes, and use more bedding than people in lowlands. Louse- borne typhus infections increase during cool, and rainy seasons, with persisting famine, poor hygienic conditions and crowded living conditions have a potential for large outbreaks. Interruption of infection chains by delousing and improving living conditions are the main control measures. It should be emphasized that for effective prevention there need to be better hygienic, housing, socio-economic and health services. Chloramphenicol and tetracyclines are effective against typhus. Additionally, a single dose of doxycycline is also curative. In conclusion, typhus still remains a serious health problem in Ethiopia, especially in institutions where overcrowding is common -prisons, schools, army camps, refugee shelters, etc. and where personal and environmental sanitation is poor. It is under diagnosed .The propagation of lice and fleas and the transmission of typhus are facilitated by persisting poverty , famine, lack of adequate hygiene, extensive population movements and civil war .
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