Introduction

Schistosomiasis also known as Bilharziasis remains one of the most prevalent parasitic worm infections and has significant economic and public health consequences. It affects many countries and appears to be endemic in many West African countries. It is mostly common in the tropical areas of the globe especially the rural areas where only the surface water bodies are the sources of water supply.

The knowledge of how intestinal parasites pass from person to person is known and variously documented ₁,₂ . and modern drugs are available, providing powerful weapons against them. Nevertheless, these infections continued to be a widespread problem and although their impact on an individual may seem slight, the global burden of the parasitic worm infections is a major health care challenge ₃ . The capacity of man to combat intestinal parasite does not seem to fall down in diagnosis and treatment, rather, it is in the low priority accorded to the control of the parasitic diseases by government of where they are endemic.

The control of schistosomiasis and indeed other intestinal parasitic infections require a combined approach involving health knowledge and awareness of risk factors for transmission.

Incidence of schistosomiasis in Nigeria and surveys reporting the prevalence in some towns and communities has been documented ₄,₅,₆,₈,₉,₁₀ . The prevalence reported in some of these earlier studies varies from 32% to 98%. Some of the reports indicated that the disease is found mostly among school children and transmission is usually focal ₁₀ . Many studies also point out that a lot of work will still be done to discover new endemic areas and to harness the predictive potential of schistosomiasis indicators to arrive at a cheaper community diagnosis and preventive protocols.

The objective of this study was to determine the prevalence and endemicity of urinary schistosomiasis in Ogbadibo local government area of Benue State, Nigeria.

Materials and Methods

The study was conducted in Ogbadibo Local Governemnt Area, Benue State. The local government was divided into five zones for effective coverage. The zones include Aiona, Owukpa, Eha, Ijadoga and Otukpa. Winners hospital Aiona, St, Theresa hospital Owukpa, F.S.P. Clinic, Eha Comprehensive health centre Ijadoya and the General Hospital Otukpa were the health institution used to collect urine samples from patients. The information on age, sex and source of water supplies was obtained from the patients.

A total of 657 urine samples comprising 329 samples from males and 328 samples from females were collected and examined. The urine samples were collected in 250ml universal sample bottles and taken to the laboratory where they were analyzed. The presence of visible haematuria in any sample was noted and recorded. The centrifugations and sedimentation techniques (WHO, 1991) was employed to analyze the samples. 10ml urine was taken from the deposit of each specimen bottle after allowing to sediment for about I hour and centrifuged for 2mins at 2000rpm. The deposit was thereafter examined microscopically using X10 and X40 objectives for the characteristics schistosoma egg or ova.

The freshwater habitats in all the zones were visited and snail search was conducted in each of them. Snails found were picked and put in wide mouth plastic buckets and taken to the laboratory where they were screened for Cercariae after exposure to sunlight for about 3hours (Emejulu et al 1994).

Results

The prevalence of urinary schistosomiasis in different zones in Ogbadibo local government of Benue State is presented in Table 1. The result shows that of a total of 657 urine samples examined, 300 (45.6%) showed the presence of Schistosoma haematobium eggs. Owukpa and Eha zones showed higher prevalence (10.8% and 10.35% respectively) than other zones. The prevalence of the infection in relation to sex is also shown in Table 1. The result shows that of 329 male urine samples examined, 152 (23.13%) showed the presence of S. haematobium eggs while 148 out of 328 (22.53%) female urine samples examined contained the eggs.

The prevalence rate of the disease with respect to age is shown in Table 2. The result shows that the infection rate uniquely cut across all the age brackets studied although the prevalence appears slightly higher among the age bracket 11-20 years. The survey of freshwater habitat resulted in collection of many snails and many of them yielded Schistosoma cercariae. Many of the snail species were identified as Bulinus species known to be intermediate hosts for Schistosoma haematobium. The analysis of the haematuria samples showed that majority of the urine samples with blood stains contained Schistosoma haematobium eggs.

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Discussion

The global problem of tropical diseases has continued to grow over the years against wide spread optimism that prevailed in the 1950s among those working in the field of public health that tropical diseases including schistosomiasis would soon be things of the past. The result of this study showed a relatively high prevalence of urinary schistosomiasis (45.68%) in Ogbadibo local government area of Benue State. This prevalence is however lower than 66.4% and 76.2% reported by Adewumi [[[l2]]] in three contiguous communities in South West Nigeria. Adeyeba and Ojeaga, ₁₀ reported a close infection rate of 57.5% among school children in Ibadan, Nigeria. Edungbola et al, ₉ recorded similar infection rate among school children in Babana district, Kwara State, Nigeria.

The result of this study unlike the result of some earlier studies shows that the prevalence of the disease is not age dependent even though there was a slight increase in the prevalence rate among the age bracket of 11-20 yrs (Table 2). The statistical analysis (log linear model) showed that neither sex nor age had significant influence in the prevalence of the disease in the area. There was no sharp difference between the rate of the infection between the males 923.13%) and the females (22.53%) (Table 1). This is presumably due to equal exposure to the risk factor as there were no restrictions on movement and contact with the freshwater habitat in terms of culture, religion, sex or age. The people were seen engaged in activities that necessitate more contact times with the streams and snail intermediate vectors. Every segment of the inhabitants of the communities were observed to be making use of the streams, either for washing, fetching water, swimming, fishing, bathing or hunting for snails by the edges and fringes of the streams. The villagers eat and sell the caught snails at the village markets to even people from other parts of the country, especially those from the eastern part. The availability of various species of snails especially the Bulimus species highlights the endemicity of the disease in the area. The fact that increased contact time with Schistosoma haematobium infested habitat increases the rate and endemicity of schistosomiasis has variously been reported, ₁₃,₁₄,₂,₈,₁₅ . The slightly higher prevalence rate (9.56%) observed among the age bracket 11-20 years is expected as that is the age that appears to be more adventurous in terms of hunting for snails, and fishing.

The sub-urban settlement of Otukpa and Ijadoga within the local government headquarters have little advantage over other zones because they have government water works that supply them pipe borne water even though the supply is grossly inadequate. They still depend on streams, hand dug wells and springs for supplemental supply. This may explain why the two zones have lesser prevalence (7.3% and 7.6% respectively) than the rest of the zones (Table 1). The communities within the Owukpa and Eha zones are more remote with streams and hand dug wells as their sole source of water supply. The inhabitants have higher contact times with the schistosoma infested habitats. This can explain the higher prevalence rate (10.8% and 10.35% respectively) recorded in the two zones (Table 1).

The observation in this study that many of the urine samples with blood stains contained Schistosoma haematobium eggs is in line with observations of Emejulu et al ₈,₁₀. Emejulu ₈ however noted that the result of analysis of visible haematuria shows that it is highly sensitive as a diagnostic tool but has a very low positive predictive value because of its low specificity in many of the studied areas.

Correspondence to

Mbata, Theodore Department of Applied Microbiology and Brewing Nnamdi Azikiwe University, P.M.B. 5025, Awka Anambra State, Nigeria Email: theoiyke@yahoo.com