Observations on microepidemiology of urinary schistosomiasisin Nuba Mountains, Southern Kordofan State, Sudan

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Machar, Gabriel Atillio
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The present investigation was designed and conducted in Nuba Mountains from Period of 2002-2003, where three villages were selected as study area: Habilla, Dilling and Fayo. The main objective of the investigation was to provide the main baseline information on the crucial epidemiological aspects of Bilhariza. All children were included in the study together with the a randomly selected 50% of the villagers from each of the three residential areas. The obtained results reassured that the situation of urinary schistosomiasis was miserable, where the overall prevalence of infection was 43.2% among the villagers and 30.8% among the school children. Exactly half of the investigated villagers have the history of infection, where (18.6%) of them were still suffering the infection. It appears that the three villages have the same rate of the infection: Fayo (47.6%), Habilla (43.8%) and Dilling (36.5%). The finding highlighted that Dilling has a considerable proportionate of worm burden, expressed in excreted eggs (107.2 eggs/10ml of urine). The infection parameters of urinary schistosomiasis varied with age-classes, where the infection significantly peaked at the age-class of (10-20) years among the population, and the age-class (> 15) years among the school children. Concerning the interspecific variations of infection parameters, the analysis suggested significant differences in worm burden in the three villages, on gender basis. Although the proportion of infection varied among the males of the three villages, no appreciable variation was detected among the females, where the prevalence skewed to the lowest rates. The study also suggested that transmission seasonality of S. haematobium occurs mainly during the rainy season, from June-February. The investigation monitored the key factors in the extensive transmission and distribution of urinary schistosomiasis in the study area were proximity to waterbodies, combined with absence of latrines and poor personal and communal hygiene as well as the lack of clean water-supply. Furthermore, some of the addressed socioeconomical parameters were judged to be influential in the transmission pressure of urinary schistosomiasis. These include: the households’ educational level, occupation category, accessibility to latrine and water-supply systems. The adopted intervention reduced the prevalence rate of Bilharzia among the school children by 22.7%, while the reduction of intensity of infection postured 30.4 eggs/10ml of urine. The post-intervention findings stressed that the reduction of the prevalence rates among the infected school-children was not significant. As expressed, the observations of the villagers’ water-contact activities in/around Pools and Hafiers recapitulated that: the villagers who used to expose themselves to contaminated waterbodies were the most suffering (33.3%) and (58.8 eggs/10ml of urine). Although two-thirds of the water-contacts were predominated by the females, still the males significantly suffered both prevalence and worm burden. The findings suggested synchronized patterns of the villagers’ age-classes, to the frequencies of water-contact and the amplitudes of the two infection parameters. However, the gradual increase reaches an apex at the age class (10-20) years. In addition, the analysis of the findings stressed that the frequency of water-contacts, varied based on age-classes of the villagers. The malacological surveys, for 12 months, assured that Bulinus truncatus snails are the most abundant intermediate-host of S. haematobium in the Nuba Mountains. The number of snails collected during the study, varied in distribution, according to some important regulating factors. It appears that the interval August-November not only represented the apex of snails’ population (76.5%), but also the high snails’ infection (100%). On the other side, the field investigation on the aestivated snails highlighted that 27.3% of them were infected with non-human cercariae, while not a single aestivated snail was found liberating human-cercariae. The designed laboratory experiments stressed that the apex of the cercarial liberation from both naturally and laboratory infected snails was at 11-01 pm. Unfortunately, such interval of cercarial emission was found in symphony with the villagers ware-contact activities, thus, representing the most risky time for them to acquire infection. Lastly, based on the findings of the investigation and the stress of the fact that Bilharzia has hazardous effects on its victims, arrays of accessible recommendations were generated for adoption
Observation,microepidemiology,urinary schistosomiasisin,Nuba Mountains, Sudan