Cooccurrence of Schistosoma haematobium, other trematode parasites, an annelid (Chaetogaster limnaei limnaei), and a nematode parasite (Daubaylia potomaca) in Bulinus globosus

Cooccurrence of Schistosoma haematobium, other trematodes, Chaetogaster limnaei limnaei, and Daubaylia potomaca was investigated in Bulinus globosus collected at Nike Lake from October 2011 to September 2012. The snail sizes as well as the numbers of these organisms were recorded. Single infections of S. haematobium, other trematodes, C. limnaei limnaei, and D. potomaca were 0.3%, 46.38%, 1.03%, and 2.66%. Coinfection of S. haematobium-C. limnaei limnaei was 0.3% while that of S. haematobium-other trematodes was 0.15%. Coinfections of C. limnaei limnaei-other trematodes and D. potomaca-other trematodes were 2.16% each. There was no cooccurrence of C. limnaei limnaei-D. potomaca or S. haematobium-D. potomaca. The mean intensity of C. limnaei limnaei-S. haematobium was significantly higher than C. limnaei limnaei single infection. The mean intensity of single C. limnaei limnaei infection and C. limnaei limnaei-other trematodes coinfection was comparable. Mean intensity of D. potomaca-other trematodes coinfection and D. potomaca single infection was similar. In relation to snail size, significant variation was observed in other trematodes infection where the snails ≥8 mm had significantly higher infection rates than the snails <8 mm. The varying prevalence and mean intensities of the various symbionts in B. globosus suggest the existence of biotic interactions.