Occurrence and seasonality of internal parasite infection in elephants, Loxodonta africana, in the Okavango Delta, Botswana.

Lydia Baines,Mphoeng Ofthile,Eric R Morgan,Kate Evans

doi:10.1016/j.ijppaw.2015.01.004

Lydia Baines, Mphoeng Ofthile + Show 2 more

Open Access

https://doi.org/10.1016/j.ijppaw.2015.01.004

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Abstract

It is known from studies in a wide range of wild and domestic animals, including elephants, that parasites can affect growth, reproduction and health. A total of 458 faecal samples from wild elephants were analysed using a combination of flotation and sedimentation methods. Coccidian oocysts (prevalence 51%), and nematode (77%) and trematode (24%) eggs were found. Species were not identified, though trematode egg morphology was consistent with that of the intestinal fluke Protofasciola robusta. The following factors were found to have a significant effect on parasite infection: month, year, sex, age, and group size and composition. There was some evidence of peak transmission of coccidia and nematodes during the rainy season, confirmed for coccidia in a parallel study of seven sympatric domesticated elephants over a three month period. Nematode eggs were more common in larger groups and nematode egg counts were significantly higher in elephants living in maternal groups (mean 1116 eggs per gram, standard deviation, sd 685) than in all-male groups (529, sd 468). Fluke egg prevalence increased with increasing elephant age. Preservation of samples in formalin progressively decreased the probability of detecting all types of parasite over a storage time of 1-15 months. Possible reasons for associations between other factors and infection levels are discussed.

Highlights

Parasites can reduce body condition, reproductive success, and survival in their hosts (Irvine, 2006)
Due to the relatively limited amount of work that has been carried out on these parasites in African elephants, very little is known about their identity, occurrence, importance, life cycles and transmission dynamics
In addition to samples from wild elephants, 79 faecal samples were collected from the seven individuals of the Abu herd

Summary

Introduction

Parasites can reduce body condition, reproductive success, and survival in their hosts (Irvine, 2006). Parasite infections have been associated with mortality in the African elephant, Loxodonta africana (Vitovec et al, 1984; Obanda et al, 2011), research on the parasite fauna of this species is limited. The elephant-specific intestinal fluke Protofasciola robusta, likely to be an ancestral species within the Fasciolidae (Lotfy et al, 2008), has been associated with intestinal tissue damage, haemorrhage and death in free-ranging African elephants (Vitovec et al, 1984; Obanda et al, 2011). While apparently common, have not been widely associated with adverse clinical consequences (Fowler and Mikota, 2006)

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