Effects of Host Demography, Season and Rainfall on the Prevalence and Parasitic Load of Gastrointestinal Parasites of Free-Living Elephants (Loxodonta africana) of the Chad Basin National Park, Nigeria

Abstract

The effects of host demography, rainfall and season on the prevalence and parasitic load of gastrointestinal parasites of African elephants (Loxodonta africana) of the Chad Basin National Park were determined for the first time. Out of the 274 elephants examined, 36.86% were infected. Of the 178 males examined, 35.96% harboured Strongyloides, Coccidia and Strongyles with worm burdens of 75.6 +/- 0.3, 125.2 +/- 1.4 and 420.2 +/- 0.1, respectively. Among the males, the larvae of Strongyloides papillosus were recovered from those infected with Strongyloides while Haemonchus contortus, Trichostrongylus colubriformis, Murshidia species and Oesophagostomum columbianum were recovered from those infected with Strongyles. Those infected with Coccidia yielded Eimeria bovis. Of the 96 females examined, 38.54% were infected with Coccidia and Strongyles with 102.2 +/- 0.7 Oocysts per Gram of faeces (OPG) and 360.2 +/- 0.1 Eggs per Gram of faeces (EPG), respectively. The helminth larvae recovered from the females infected with Strongyles were; H. contortus, O. columbianum and Murshidia species, while those infected with Coccidia yielded E. bovis. Out of the 213 adults examined, 27.23% were infected with Strongyloides and Strongyles with 187.3 +/- 0.4 and 208.4 +/- 0.1 EPG, respectively. The larvae of S. papillosus were recovered from those infected with Strongyloides, while the larvae of H. contortus, O. columbianum, T. colubriformis and Murshidia were recovered from those infected with Strongyles. Of the 61 young examined, 70.49% were infected with Coccidia and Strongyloides with OPG of 88.4 +/- 0.2 and EPG of 624.4 +/- 0.2. The elephants were mostly infected in the rainy season. The worm burden and prevalence according to sex and age were highest in August. The males and young were more infected than their counterparts. In conclusion, intrinsic and extrinsic factors played a role on the prevalence and worm burden of gastrointestinal parasites of elephants of the Chad Basin National Park.