Schistosomiasis prevalence in Zomba, Southern Malawi

Abstract

A large proportion of Malawi's more than 13 million people live in rural areas where major livelihood activities include subsistence farming, irrigation and fishing. Therefore the villagers have contact with water, which exposes them to schistosomes. In this case study, surveys and parasitological investigations were conducted to determine the prevalence of schistosomiasis and to explore the relationship between disease prevalence and selected qualitative variables in five villages located in Zomba District in Lake Chilwa Basin. The study revealed a high prevalence, ranging from 23% in Machemba village to 49% in Mukhweya village. Children, 6-15 years old, were the most heavily infested (40%), and the 0-5 years group the least. A high prevalence was observed among school children (39%), and occupations such as irrigated farming (26%) and fishing (24%). Analyses at the 0.05 α-level revealed statistically significant associations between schistosomiasis prevalence and village of residence, age group and occupation type, but there was insufficient evidence to suggest a significant relationship with gender. Based on these findings, targeted awareness and mass treatment programmes were implemented in all the villages, and 9085 people were treated.

Schistosomiasis in Malawi: a systematic review

“…Thus, 97% of the reviewed documents included urinary schistosomiasis, whereas only 40% covered at least one aspect of intestinal schistosomiasis; more than one third included both forms of schistosomiasis and only 3 documents exclusively addressed intestinal schistosomiasis. This finding may be explained by the observation that urinary schistosomiasis is more common and widely distributed in Malawi and thus comprises a larger public health problem than intestinal schistosomiasis [20,23,26,31,103]. It may also be explained by the observation that urinary schistosomiasis is common in the major tourist destinations around Lake Malawi and thus receives substantial international attention [25,28,30,36,39,45,46,55,91,97]; this may further explain the observation that the human aspects of urinary schistosomiasis receive more attention than other aspects of the infection [110].…”

“…Prevalence studies carried out in selected locations nationwide between 1988 and 2014 revealed substantial variation in the prevalence of both S. haematobium and S. mansoni [20,23,26,29,31,32,45,58,71,75,80,85,103,105,108]. Some of this variation is caused by differences in distribution and transmission, and some is caused by differences in methodologies used in various studies.…”

“…The remaining 7 (27%) surveys combined human infections with both S. haematobium and S. mansoni, and they reported infection prevalence rates ranging from 2.0% to 94.5% and from 0% to 67.0%, respectively, in the northern highlands, central lowlands, southern lowlands, urban areas, Chikhwawa and Chizumulu Island. These survey findings suggest that urinary schistosomiasis is more common and widely distributed in Malawi, and thus comprise a larger public health problem, than intestinal schistosomiasis [21,23,26,31,75,78,103].…”

“…The effects of unsafe water and lack of sanitation on the distribution and transmission of schistosomiasis in Malawi have been well documented [21,23,26,29,31,75,80,103]. Several studies have addressed the effects of ecological and environmental changes on the distribution and transmission of schistosomiasis in Malawi [40,57,58,65,69,70,73,100,106].…”

“…Even though most of the reviewed publications derive from single-standing studies, four major groups of scientists have contributed comprehensively to publishing the findings from their research. These groups comprised several researchers who collaborated on specific research programs on schistosomiasis and related aspects in Malawi, namely 1) a group from Malawi, particularly from institutions within the University of Malawi, involved in publishing 17 (36%) scientific papers [6,19,20,23,26,29,31,55,75,80,83,84,96,99,101,102] as first authors; 2) a group from USA involved in publishing 13 (28%) scientific papers [32,45,61,[67][68][69][70][71][72][73]100,106,107] as first authors; 3) a group from Denmark involved in publishing 10 (21%) scientific papers [6,[57][58][59]63,66,74,85,105] as first authors and 4) a group from Norway involved in publishing 7 (15%) scientific papers [24,27,[41][42][43]…”