Epidemiological Assessment of Vesical Schistosomiasis in Bende Local Government Area of Abia State, Nigeria

A survey was carried out between January and July 2002 to determine the prevalence of vesical schistosomiasis in Bende Local government area of Abia State. A total of 2406 persons in eleven communities aged between 6 and 60 years were examined. Prevalence rates in the eleven communities ranged between 25.5% and 52.3% with an overall prevalence of 41.5%. More males (42.6%) than females (39.4%) were infected in all the age groups, and high rate of haematuria (78.2%) was observed among the infected subjects. Infection prevalence was significantly higher (65.3%) among those in the age group of 11 – 20 years (P < 0.05) than those above 60 years. More than 70% of those infected excreted above 50 eggs/10ml urine. Malacological studies conducted along water bodies in the study area indicated that infection was localised. Bulinus globosus is implicated as the potential disease intermediate host. @JASEM Schistosomiasis is a water-associated disease caused by the digenetic trematode of the genus Schistosoma. It constitutes one of the most important parasitic diseases of man (Adeoye and Akabogu 1996), and is second only to malaria in its socio-economic and public health implications (Anosike et al 2002). Vesical schistosomiasis (caused by Schistosoma haematobium) alone constitutes a major public health problem in 44 African countries (WHO 1995) and is endemic in Nigeria. About 200 million people in some 74 countries are infected world wide; and at least another 600 million are at risk of infection (WHO 1995). An estimated 120 million suffer severe consequences of the infection with an estimated annual mortality rate of about 20,000 world wide (WHO 1998). An estimated 30 million Nigerians need to be treated annually for the disease (Anosike et al 2003). In most endemic areas, the highest intensities of infection are found in children between 5 and 15 years of age (WHO 1998). The planorbid snail Bulinus is the intermediate host in the transmission of vesical schistosomiasis. The distribution of the disease is focal and its effects are more felt in the rural areas of the tropics where the population uses natural fresh water habitats for their domestic water supply and or agricultural production. Hence the disease transmission therefore is contingent on the presence of infected water, the primary snail host and contact with human population. Apart from the earlier studies of Nduka et al (1995) and Anosike et al (2000, 2001), in parts of Abia State, information on the disease and its snail vector in Bende area of Abia State is fragmentary. The present study therefore is an epidemiological assessment of the disease among the people of Bende local government area, South Eastern Nigeria. MATERIAL AND METHODS The study area: The area of coverage is Bende local government area of Abia State, South Eastern Nigeria with a population of about 176,565 people based on the 1991 population census; and it is located in the northern part of Abia State. Abia State occupies the area lying between coordinates 65’ and 450’N and between 708’ and 800’E. The vegetation is typical of southern rain forest zone and there are two distinct seasons; the wet season lasting from April to September and the dry season beginning in October through March. Anosike et al (2001) gave the range of annual rainfall in Bende area to be between 200 and 250cm and the mean annual temperature to be 27C – 35C. The major occupation of the people of the area is farming, and rice farming is predominant. Other crops produced include cassava, maize, and beans. The area is essentially a rural setting and in all the communities surveyed, there were no pipe-borne water. The main sources of water for domestic and agricultural use are streams and ponds; and the streams are surrounded by rice farms and weeds that aid in the breeding of the snail intermediate hosts of schistosome. Eleven villages were randomly selected for the survey; and they are Ogboko, Isiegbu, Eziaja, Ofiavu, Obuofia, Umuolazi, Ndiagbo, Ebem, Eluama, Umuokebe and Ndianya. Epidemiological survey: A survey of vesical schistosomiasis was carried out from January to July 2002 in the eleven villages listed above in Bende JASEM ISSN 1119-8362 All rights reserved J. Appl. Sci. Environ. Mgt. June, 2006 Vol. 10 (2) 55 60 Full-text Available Online at www.bioline.org.br/ja Epidemiological Assessment of Vesical Schistosomiasis... Nwosu, D C; Anosike, J C; Nwoke, B E B; Uwaezuoke, J C local government area of Abia State. Urine samples were collected from individuals randomly selected on a house to house basis. Only individuals from six years and above were examined. A 25ml wide mouth, screw-cap, plastic urine container was given to each individual participating in the study, and their names, age, sex and occupation were recorded. They were properly instructed to provide mid-stream urine samples between 10am and 12 noon which corresponds to the period of peak urinary egg excretion. Specimen bottles were retired with the help of field assistants. These were sent to our central laboratory within three hours of collection, where each specimen was processed as described by Anosike et al (1998). 10ml of urine was transferred into a centrifuge tube using a sterile disposable syringe. This was centrifuged for five minutes at 5000rpm. The supernatant was discarded while the deposit was resuspended by tapping the tube, poured into a petri-dish and examined for terminal spinned eggs of S. haematobium using a binocular microscope. The eggs were also counted and recorded. After this, the sediment was diluted with 10ml of tap water, and left under light source for 30 minutes and examined for miracidia as described by Anosike et al (2003). Reagent strips (Medi-test combi -9) were used to test for haematuria and urinary blood recorded variously as positive or negative using the plus (+) and minus (–) notations as the case may be. Again, snail samples were collected from the various local fresh water habitats in the study area using a long handled scoop not. These were packed in moist leafy vegetation, put in labelled plastic bags and transported to the laboratory where they were washed, counted, identified, (using reference specimens from the Danish Bilharziasis Laboratory Charlothenlund, Denmark) and examined for cercerial shedding after the method of Anosike et al (2002).