African Wild Ruminants Research Articles

Foot-and mouth disease and peste des petits ruminants – the role of wildlife in the epidemiology and control of diseases

Foot-and mouth disease (FMD) and peste des petits ruminants (PPR) are highly contagious and an economically devastating diseases, currently endemic to the African and Asian continents. The aim of this paper was to present the role of wildlife in the epidemiology of both diseases. There are more than 100 species of wild, feral, laboratory, or domesticated animals that have been infected naturally or experimentally with FMD or PPR viruses. Experimental infections of several African wild ruminants can result in clinical FMD. African buffalo represents the best known FMD wild host reservoir in Sub-Saharan Africa. North American mule deer were found susceptible to FMDV infection with significant mortality. Other wild ruminants such as impala can also contribute to FMDV maintenance. In Europe several deer species and the Eurasian wild boar are susceptible to FMDV. PPRV has been reported to have infected some wildlife, such as African buffalo, saiga antelope, dorcas gazelles, gemsbok, Nubian ibex and some other ungulate species. The role of wildlife in FMD and PPR epidemiology may concern wildlife as indicators, victims, bridge hosts or maintenance hosts for both diseases. In addition, they are occasionally victims of disease outbreaks, and they are often relevant for disease management as either bridge or maintenance hosts. Wildlife deserves to become a key component of future integrated surveillance and disease control strategies in an ever-changing world. However, it must be stated that efforts to control FMD and PPR in wildlife may not be successful when the diseases are endemic in livestock and may cause more harm to wildlife, human livelihoods, and domestic animals.

First survey of ticks, tick-borne pathogens (Theileria, Babesia, Anaplasma and Ehrlichia) and Trypanosoma evansi in protected areas for threatened wild ruminants in Tunisia.

The aim of the study was to identify ticks present in the environment and wild Tunisian ruminants and to detect tick-borne pathogens and Trypanosoma evansi DNA in these specimens. Sampling was done throughout each season from the environment in three protected areas around Tunisia: El Feidja, Haddaj and Oued Dekouk. Ticks were collected also, from one fawn of Barbary red deer and eight naturally deceased wild ruminants (one Barbary red deer, five Scimitar-horned oryx, one Addax antelope and one Dorcas gazelle), all of which lived in various protected areas. PCR and nested PCRs were performed to detect the presence of Theileria spp., Babesia spp., Trypanosoma evansi, Ehrlichia spp., Anaplasma spp., Anaplasma bovis and Anaplasma phagocytophilum DNA in these tick specimens. A total of 352 ticks were collected, belonging to six different species: Hyalomma excavatum (80.6%), Hyalomma dromedarii (10.2%), Hyalomma marginatum (0.5%), Rhipicephalus bursa (0.5%), Rhipicephalus sanguineus sensu lato (5.1%) and Ixodes ricinus (2.8%). Pathogens have been detected in 25% of H. dromedarii, 9.1% of H. excavatum and 5% of R. sanguineus sensu lato. The percentage of detection of T. evansi was 0.2%. Ehrlichia spp.-Anaplasma spp. were detected in 10.1% of ticks. Anaplasma spp. and A. bovis were detected in 7.6%, and 0.8% of examined ticks, respectively. None of the Theileria spp., Babesia spp., or A. phagocytophilum DNA was detected in the tested ticks. To our knowledge, the present study represents the first identification of these six tick species and the first detection of rickettsial pathogens and T. evansi in North African wild ruminants' species. These results extend the knowledge about the diversity of ticks and tick-borne pathogens in wildlife and justify further investigations of the possible role of R. sanguineus sensu lato in the transmission of T. evansi.

Molecular identification of parasitic nematodes (Nematoda: Strongylida) in feces of wild ruminants from Tunisia

In Tunisia and other North African countries, there is a lack of knowledge about parasite biodiversity within threatened wild ruminants and there are not any studies on their gastrointestinal nematodes. Thus the aim of this study was to identify gastrointestinal fauna in the faecal samples of Tunisian wild ruminants. A total of 262 faecal samples were collected from domestic sheep and goat, and wild ruminants (Addax, Barbary sheep, Barbary red deer, Dorcas gazelle, Slender-horned gazelle and Scimitar-horned Oryx) living in protected areas. Samples were examined with floatation (saturated sodium chloride solution), polymerase chain reaction and sequencing of the second internal transcribed spacer region of the rDNA. Microscopic analysis allowed the identification of only Nematodirus genus or molecular tools allowed a first identification of five gastrointestinal nematode species in North African wild ruminants: Chabertia ovina (1.6%), Camelostrongylus mentulatus (1.6%), Marshallagia marshalli (4.7%), Nematodirus helvetianus (62.5%) and Nematodirus spathiger (29.7%). This study reported the first records of C. mentulatus and M. marshalli in Addax and of M. marshalli in Dorcas gazelle and it was the first reported record of N. helvetianus and M. marshalli in Tunisia.

Serological survey of bovine viral diarrhoea virus in Namibian and South African kudu (<i>Tragelaphus strepsiceros</i>) and eland (<i>Taurotragus oryx</i>)

Bovine viral diarrhoea virus (BVDV) is a pestivirus that affects members of the order Artiodactyla, including members of the subfamily Bovinae. Little is known about the seroprevalence of BVDV in southern Africa, especially the prevalence in wild ruminant populations such as kudu (Tragelaphus strepsiceros). A handful of random surveys suggested that seroprevalence ranged between 6% and 70% in southern African wild ruminants. The present study aimed to determine the seroprevalence of BVDV amongst kudu and eland (Taurotragus oryx) from Namibia and South Africa. A BVDV-specific enzyme-linked immunosorbent assay was performed on 50 serum samples from kudu and eland from South Africa and Namibia. The seroprevalence of BVDV in South African kudu was 71%, identical to that in Namibian kudu. The seroprevalence in Namibian eland was 40%. The kudu and cattle farming (free ranging) regions in Namibia predominantly overlap in the central regions, ensuring ample opportunity for cross-species transmission of BVDV. It is therefore important to determine the true prevalence of BVDV in southern Africa in both domesticated and wild animals. In addition, a potential link between BVDV incidence and a devastating rabies epidemic in Namibian kudu was proposed and such a notion could be supported or discredited by comparative prevalence data.

Ticks associated with the three largest wild ruminant species in Southern Africa

The objective of this study was to assess the host status of the three largest southern African wild ruminants, namely giraffes, Giraffa camelopardalis, African buffaloes, Syncerus caffer, and eland, Taurotragus oryx for ixodid ticks. To this end recently acquired unpublished data are added here to already published findings on the tick burdens of these animals, and the total numbers and species of ticks recorded on 12 giraffes, 18 buffaloes and 36 eland are summarized and discussed. Twenty-eight ixodid tick species were recovered. All stages of development of ten species, namely Amblyomma hebraeum, Rhipicephalus (Boophilus) decoloratus, Haemaphysalis silacea, Ixodes pilosus group, Margaropus winthemi, Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi, Rhipicephalus glabroscutatum, Rhipicephalus maculatus and Rhipicephalus muehlensi were collected. The adults of 13 species, of which the immature stages use small mammals as hosts, namely Haemaphysalis aciculifer, Hyalomma glabrum, Hyalomma marginatum rufipes, Hyalomma truncatum, Ixodes rubicundus, Rhipicephalus capensis, Rhipicephalus exophthalmos, Rhipicephalus follis, Rhipicephalus gertrudae, Rhipicephalus lounsburyi, Rhipicephalus lunulatus, Rhipicephalus pravus group and Rhipicephalus simus, were also collected.

Identification of myosin heavy chain isoforms in skeletal muscle of four Southern African wild ruminants

The aim was to separate and characterize the myosin heavy chain (MHC) isoforms of four southern African wild ruminants, namely Blesbuck ( Damaliscus dorcas phillipsi), Kudu ( Tragelaphus strepsiceros), Black Wildebeest ( Connochaetes gnou) and Blue Wildebeest ( Connochaetes taurinus). Longissimus dorsi muscle samples were subjected to SDS-PAGE and Western blot analyses using antibodies raised against MHC isoforms. The specificity of these antibodies was assessed using immunohistochemistry combined with ATPase histochemistry, Three MHC isoforms were separated and the bands were identified from fastest to slowest migrating as MHC I, MHC IIx and MHC IIa. The mobility of the MHC isoforms was similar for all four species, including that of bovine, but differed from human muscle. Kudu muscle exhibited the lowest proportion of MHC I and the highest proportion of MHC IIx, whereas Blesbuck muscle had the least MHC IIx. The two Wildebeest species were intermediate in isoform content. In conclusion, when new species are studied, existing electrophoretic protocols may need to be modified to achieve quantifiable separation and isoform migration pattern must be verified in order to reach correct interpretations. Furthermore, antibody specificity may differ between techniques as well as species and needs confirmation.

Influence of diet on the rumen protozoal fauna of indigenous African wild ruminants.

A study was carried out to determine if the protozoal fauna of indigenous African wild ruminants was different from that found in their domestic counterparts and if the animal's diet influenced the number and types of protozoa. Samples of rumen contents were collected in 1997 and 2001 from various indigenous African wild ruminants in Kenya. All three ruminant feeding types were sampled: browsers or concentrate selectors (giraffe and Guenther's dik-dik); intermediate or adaptable mixed feeders (impala, Thomson's gazelle, Grant's gazelle and eland); grass or roughage eaters (hartebeest and wildebeest). Total concentration of ciliate protozoa and percentage generic distribution were determined. In general, protozoal concentrations were higher in concentrate selectors, followed by the intermediate or opportunistic mixed feeders and lowest in the grass and roughage eaters. Both Thomson's and Grant's gazelle were protozoa-free in the 2001 samples. Entodinium percentages were considerably higher in concentrate selectors and intermediate mixed feeders, compared to roughage eaters. Two genera of protozoa previously found in only a few African ruminants, Epiplastron and Opisthotrichum, were observed in several additional animal species and represent new host records. A difference was noted in the protozoal species composition of the indigenous wild ruminants from that previously observed in African domestic ruminants.

Colonic absorption and secretion of fluids, electrolytes and organic acids in East African wild ruminants

1. 1. In sixteen species of wild ruminants colonie absorption of fluids averaged 48% of the fluids entering the large bowel. Values ranged from 26% (steenbok) to 65% (gerenuk). 2. 2. Absorption of sodium, potassium, chloride and organic acids were variable between species. 3. 3. Colonie absorption of potassium ions were found to be related to diet selection and body weight of the animals. 4. 4. Colonie absorption of volatile fatty acids were significantly greater in browsers (28.4 mmol/l) than grazers (9.6 mmol/1). 5. 5. The African buffalo are the only species of wild ruminants not forming a faecal pellet ; colonie functions were not different from those species forming faecal pellets.

Molar proportions of volatile fatty acids in the gastrointestinal tract of East African wild ruminants

1. 1. The molar proportions of seven individual VFA's were determined at select sites along the gastrointestinal tract of sixteen species of East African wild ruminants. 2. 2. The resulting data were statistically analyzed for species effect, and for effects due to major feeding groups (browsers, grazers, fresh grass grazers, etc.) and for body weight groups (5–750 kg animals). 3. 3. Present data suggest that body weight, rather than diet, is the more influential factor in reticulo-rumen fermentation rate, and in the molar proportion of fatty acids present. 4. 4. The molar proportions of VFA's observed in the mid and hindgut of these wild ruminants appeared more responsive to diet and body weight of the animal than did foregut VFA values.

Digestive physiology of East African wild ruminants

1. 1. The physiology of digestion of wild ruminants in their natural habitat was determined. The study consisted of fifty-one adult male animals representing sixteen species. 2. 2. While diet and body weight were both related to the gastrointestinal composition, body weight appeared to be the more influential factor. 3. 3. Reticulo-rumen and caecal-colon composition, relative to abomasal and small intestinal composition, showed the greater species, diet and body weight effects. 4. 4. The buffalo, oryx and gerenuk were somewhat more unique in gastrointestinal composition than were other species of wild ruminants, and were deserving of special consideration.

Aspects of digestion and in vitro rumen fermentation rate in six species of East African wild ruminants

Studies were carried out to compare digestive functions in six species of East African wild ruminants (viz. African buffalo, giraffe, Eland, waterbuck, oryx and Gerenuk). Digestive processes within the reticulorumen, abomasum and caecum of each species were assessed by measurements of pH, ammonia‐nitrogen, osmolality, volatile fatty acids, lactic acid and in vitro fermentation rates. Blood glucose and serum urea‐nitrogen were also measured in all species. The results are discussed in relation to the dietary habits and ecology of each species.

Vitamin A storage in the liver of certain African wild ruminants and elephant

The levels of vitamin A were determined in liver samples from 40 animals including ruminant species feeding on grass (4 buffalo, 6 blue wildebeest, 5 gemsbok) or mainly on plant material other than grass (10 impala, 3 springbok, 7 kudu and 5 elephants). The mean values obtained for the ruminant species ranged from 212 to 1217 I.U. vitamin A/g liver fresh weight mass and showed no relationship to the percentage of grass in rumen contents. An unusually low level of 67 I.U. was found in elephant.

A study of feeding types and certain rumen functions in six species of South African wild ruminants

SUMMARYIn order to characterize the rumen digestive physiology of South African wild ruminants investigations were made on a total of 35 individuals of six species killed in various regions during the dry season.In buffalo, blue wildebeest and gemsbok grasses constituted 85–100% and in impala, springbok and kuduless than 10% of the diet. In the case of the latter three species effects of the habitat and of predilection for certain plant materials were apparent.Compared with the grazers, the species feeding mainly on plant material other than grass were characterized by a smaller physiological capacity of the rumen reticulum, higher counts of ciliate protozoa and ‘large bacteria’, higher levels of rumen ammonia and higher molar proportions of rumen propionate and valerate. Within these feeding types differences between species were indicated.