Authors

AA Bayegun²; FA Adebayo²; KO Ademolu²; OP Akinwale³; PV Gyang³; JR Stothard¹; UF Ekpo²;  ¹ Liverpool School of Tropical Medicine, UK;  ² Federal University of Agriculture Abeokuta, Nigeria;  ³ Nigerian Institute of Medical Research, Yaba, Lagos, Nigeria

Discussion

There is a growing concern of hybridization between Schistosoma haematobium and Schistosoma bovis, where humans and livestock shared same surface water in schistosomiasis endemic communities. The implication of livestock as reservoir for human infection is worrying. This study investigated the possible occurrence of Schistosoma hybrids using egg morphology and PCR screening. Schistosoma eggs were collected from human urine in Imala-Odo, Abule-Titun, Apojula and Ibaro-Oyan communities, Oyan Rivers dam area, Ogun State, Nigeria. The eggs were counted, photographed, and measured for Total Length (TL), Maximum Width (MW), and Egg Shape (L/W) with IC Measure™. Unusual eggs shapes were characterized by PCR amplification of Schistosoma specific Dra1 gene. Positive amplicons for the Dra1 gene were further subjected to PCR amplification of an ITS-2 rDNA. A total of 1,984 Schistosoma eggs were collected. The total length ranges from 70.90 - 262.30µm and Maximum Width ranges from 30.10 - 102.60µm. Egg shape ranges from 1.60 - 4.06µm. There was significant variation (p < 0.05) in egg morphology, where 67.8% of the eggs had typical round-to-oval shape of S. haematobium, 32.2% were atypical spindle-shaped of hybrid S. haematobium / S. bovis and 1.1% of the eggs were spineless. PCR screening revealed 54 (62.1%) and 33 (61.1%) of the eggs were positive for Dra1 and ITS-2 genes respectively and of Schistosoma origin. DNA sequencing of spindle-shaped eggs is currently ongoing. These observations suggest that Schistosoma hybrids may be circulating in human population in the study area.