Molecular Characterization and Detection of Infection in Vector Snails of Urinary Schistosomiasis around Erinle and Eko Ende Dams in South West Nigeria

Aims: The prevalence of the schistosome cercariae in snail intermediate hosts has been known as one of the valuable predictors of the level of schistosomiasis transmission in different localities. This study was undertaken to determine molecular characterization and detection of infection in vectors snails of urinary schistosomiasis around Erinle and Eko-Ende Dams, South western Nigeria.

Study Design: Epidemiological survey.

Place and Duration of Study: Medical Microbiology and Parasitology Department, Obafemi Awolowo College of Health Science, Olabisi Onabanjo University, Sagamu, Ogun State, Nigeria between January 2010 and November 2012.

Methodology: The snails collected from communities around Erinle and Eko-Ende dams were identified using standard morphological keys. The infectivity of the Bulinus species by Schistosome was determined through cercaria shedding and Polymerase Chain Reaction (PCR) of amplification of Dra 1 gene repeats of S. haematobium while snail characterization was done using PCR-RFLP.

Results: Of the 277 snails screened, 78 (28.28%) were positive for cercaria shedding while 108 (38.98%) were positive for PCR screening. There was significant difference in the infectivity status determined by cercaria shedding and the PCR technique (p=0.05). All the snails characterized by PCR-RFLP were Bulinus. truncatus showing the species is involved in the transmission of urinary schistosomiasis in the study area.

The relatively high prevalence of schistosome infection in snail intermediate hosts around the two dams suggests active transmission of urinary schistosomiasis and underscores the need for integrated control in tackling the menace of the disease at the study area.