ABSTARCT
In the course of this study, two species of water turtles; Pelomedusa subrufa and Pelusios castenus derbianus were examined for parasites. Pelusios castenus harboured more parasites than P. subrufa.
Of the parasites encountered, Camallanus sp was common to the two species of water turtles examined, but it had a higher prevalence in Pelomedusa subrufa (88.89%). It was the only nematode parasite found in Pelomedusa subrufa. Ugezu (2008) reported Camallanus sp. in the mouth, stomach, oesophagus and small intestine of P. subrufa and P. niger fromOroma in Anambra State. Ekhorutomwen (2005) also reported Camallanus sp.from the stomach and small intestine of P. subrufa and P. niger. Fagbemi (2004) examined turtles from the rainforest and savanna-mosaic of Edo State and recorded Camallanus sp. which was identified as Serpinema sp. The spicules of the male parasite resembled the spicules of Camallanus dimitrovi (with forked terminal) which infects the bull frog, Dicroglossus occipitalis (Aisien et al., 2001). The specimens from this work also had this character. It thus appears that these water tutles are infected by a common Camallanus species. This parasite appears to be the most commonly encountered nematode in the water turtles so far investigated in Nigeria. Camallanus spp. have been reported to infect other water turtles. Mishra and Gonzalez (1978) reported finding C. parvus, in Clemmys caspica leprosa and Emys arbicularis which was recorded in almost 60% of the specimens examined. Other Camallanus sp. reported from turtles include C. nigrescens from the intestine of Kachuga tectum tectum in India (Henry, 1915), C. kachuga from Kachuga smithi (Baylis and Daubney 1922), C. lissemyus from the intestine of Lissemysus punctata punctata from India (Gupta and Singh, 1959).
As recorded in previous studies Polystomoides chabaudi was recovered from the urinary bladder of Pelomedusa subrufa. This monogenean was first described by Euzet and Combes (1965) from the urinary bladder of P. subrufa caught in Madagascar. The parasite was later reported from the same host in Uganda by Tinsely (1973). Fagbemi (2004) reported the occurrence of this parasite in P. subrufa but was reportedly found in the buccal cavity with a prevalence of 7.14%. Ekhorutomwen (2005) reported P. chabaudi from the urinary bladder of P. subrufa with a prevalence of 12.9% while Numdi (2006) found the same parasite with a much higher prevalence of 55.6%. Pelusios castaneus wasinfectedwith P. bourgati. Numdi (2006) reported the same monogenea in the urinary bladder of Pelusios castaneus from Delta state with a prevalence of 27.3%. It was the probably the first report of this parasite from water turtles in Nigeria. This parasite was described by Combes and Kulo (1978) from P. castenus derbianus taken in Togo. Enabulele et al. (2012) also reported Polystomoides bourgati from the urinary bladder of P. castenus in Southern Nigeria. It was observed that the vitelline follicles of the parasites recovered were varied in their structure. In some specimens, the follicles were "fine" while some others were coarser. Tha authors also reported that two of the parasite specimens recovered from some of the turtles had seven haptoral suckers instead of six normally found in polystomes. Another Polystomoides species parasitizing turtles in Africa is Polystomoides nabedei which is also parasitic in the urinary bladder of Pelomedusa subrufa (Kulo 1980). This species was not recorded in this study. Other Polystomoides spp reported elsewhere include Polystomoides malayi (Rhode, 1963) found in the urinary bladder of Cyclemys amboinensis. Polystomodes asiaticus inhabits the oral cavity of Cuora amboinensis (Rhode, 1965). Mishra and Gonzalez (1978) reported finding P. tunisiensis inthe buccal cavity of Clemmys caspica.
