Risk factors for schistosoma hematobium in northern rural villages in Unguja island, Zanzibar

Abstract

Back ground Schistosomiasis continues to be a scourge of the health of people living in sub-Saharan Africa with a yearly ascribed death rate of over 200,000. In Zanzibar, Schistosoma haematobium is a public health problem but the level of its prevalence varies from one area to another. In endemic areas, the prevalence and intensity of schistosomiasis is usually higher in children than in adults, giving rise to typically convex age-infection profiles. Recently, most schistosomiasis based research in Zanzibar has focused on parasite infections, transmissions and control strategies and very few studies have reported on the risk factors for Schistosoma haematobium in the islands. On the other hand studies on the health effects of schistosomiasis have been carried out particularly to school age children. Therefore, there is need for updated information on the extent of disease burden and factors associated with infection in the Island, so as to simplify effective prevention and control programme. Main Objective of the study To examine associations of schistosomiasis infections with behavioral, soci-economic and environmental risk factors among people of northern rural villages at Unguja Island in Zanzibar. Methodology This study was conducted in six (6) villages between March and June 2012 to represent northern rural villages in Unguja Island where schistosomiasis is endemic. The study design was a cross sectional study in which an unstructured questionnaire was used to produce the data. Urine samples were collected and tested by using haemastix so as to detect blood and then all urine samples were examined for Schistosoma haematobium ova using filtration method. The multi stages sampling procedure was deployed to select participants during this study. The sample size was 438. Data were entered, processed and analyzed by using SPSS 13.0. Based on the low prevalence encountered in this study we have failed to generate ix Multivariate logistic regression analyses of the relationship between Schistosoma haematobium with available risk factors. Result About 438 people of whom (211, 48.2%) males and 227, 51.8% females), were registered with a mean age of 21.19 and (S.D.) of 13.31 years and a median of 17 years. All subjects submitted urine sample and all were included in the data analysis. The age of the participants varied from ( children between 6 to 15 years old), this is due to the fact that, School children, aged around 6 and 15 years have the highest infection rates as well as the highest worm burden, which contribute greatly to contamination of the environment with infective stages of the parasites (WHO, 1995) and adults aged between 16 to 70 years old. Most participants reported having completed either primary (n = 210, 48%) or secondary (n= 112, 25.6%) level education. In general, (n= 100 22.8%) individuals were with no formal education, mostly in the age of 7–55 years. Most common occupations were students (n = 183, 41.78%) or farmers (n = 157, 35.9%), only 1.6% of the participants were government employees. About 85% were from family with income less than Tshs. 100,000/= per month. Schistosoma haematobium eggs were found in 31 (7.1%) individuals. Infection was higher in males compared with females (9.0% versus 5.3%) however this difference was not statistically significant, Chi-square = 2.2989 and P value = 0.129. Across age intervals, infection was higher between 7-17 years at 67.7% compared to the 18 – 35 years which was 29.0% and for the 36-55 years and over the prevalence was 3.2%. This showed that, prevalence decreased as age was increasing. Conclusion The findings from this study present an important update on the position of infection in this part of Tanzania and it will guide the policy makers to design extra reasonable, ample and integrated schistosomiasis control programme in Zanzibar.