Disease risks associated with the translocation of wildlife.

Translocation is defined as the human-managed movement of living organisms from one area for free release in another. Throughout the world, increasing numbers of animals are translocated every year. Most of these movements involve native mammals, birds and fish, and are made by private and national wildlife agencies to augment existing populations, usually for sporting purposes. The translocation of endangered species, often to reintroduce them into a part of the historical range from which they have been extirpated, has also become an important conservation technique. The main growth in reintroduction projects over the last decade has involved smaller animals, including amphibians, insects and reptiles. The success of potentially expensive, high-profile wildlife translocation projects depends to a large extent on the care with which wildlife biologists and their veterinary advisers evaluate the suitability of the animals and chosen release site, and on the ability of the translocated animals to colonise the area. The veterinary aspects of reintroduction projects are of extreme importance. There are instances of inadequate disease risk assessment resulting in expensive failures and, worse still, the introduction of destructive pathogens into naïve resident wildlife populations. In this paper, some of the disease risks attending wildlife translocation are described. Risk assessment, involving the examination of founder and recipient populations and their habitats, is now a pre-requisite of managed movements of animals.

Fatal Sarcoptes scabiei infection of blue sheep (Pseudois nayaur) in Pakistan.

Sarcoptes scabiei was detected for the first time in skin scrapings, hair pluckings, and histologic sections from a blue sheep (Pseudois nayaur) from the Shimshali Pamir in the Karakorum range of the western Himalaya in Pakistan (36 degrees 28'N, 75 degrees 36'E). Local reports suggest many hundred animals have been affected by a severe skin disease over a 10-yr period, but the shy nature of this species and the extreme climate that they inhabit meant only a single affected animal was available for detailed evaluation. The severe skin lesions were confined to the forelegs and brisket, and many Sarcoptes scabiei mites were present in all the samples examined. Histologic preparations of the skin showed hyperkeratotic and parakeratotic hyperkeratosis of the epidermis with a severe exudative dermatosis with many polymorphonuclear neutrophils and gram-positive cocci, yet no eosinophils. These findings might suggest the lack of an appropriate immune response to the parasite or other coping strategies because there has been no abatement of the clinical signs in affected animals over several years. Treatment options are limited due to the behavior of the species and its habitat. The blue sheep is a primary source of prey for the endangered snow leopard (Panthera uncia) and continued depletion could have serious consequences for the survival of the latter.

A preliminary investigation of tuberculosis and other diseases in African buffalo (Syncerus caffer) in Queen Elizabeth National Park, Uganda.

A survey to determine the prevalence of bovine tuberculosis caused by Mycobacterium bovis and certain other infectious diseases was conducted on 42 free-ranging African buffaloes, (Syncerus caffer) from May to June 1997 in the Queen Elizabeth National Park, Uganda. Using the gamma interferon test, exposure to M. bovis was detected in 21.6% of the buffaloes. One dead buffalo and an emaciated warthog (Phacochoerus aethiopicus) that was euthanased, were necropsied; both had miliary granulomas from which M. bovis was isolated. None of the buffaloes sampled in Sector A of the park, which has no cattle interface, tested positive for bovine tuberculosis (BTB) exposure. The prevalence and distribution of BTB does not appear to have changed significantly since the 1960s, but this may be due to fluxes in the buffalo population. Serological testing for foot-and-mouth disease (FMD) demonstrated positive exposure of 57.1% of the buffaloes sampled, with types A, O and SAT 1-3, which is the first known report of FMD antibodies to A and O types in free ranging African buffaloes. Foot-and-mouth disease virus types SAT 1 and SAT 3 were isolated from buffalo probang samples. Two percent of the buffaloes had been exposed to brucellosis. None of the buffaloes tested had antibodies to rinderpest, leptospirosis or Q fever.

Bioweapons, bioterrorism and biodiversity: potential impacts of biological weapons attacks on agricultural and biological diversity.

Diseases and biological toxins have been used as weapons of war throughout recorded history, from Biblical times through to the present day. Bioweapon uses have historically been directed primarily, although not exclusively, against human populations. Specialised technicians and state-of-the-art research facilities are no longer necessary for the production or deployment of many known bioweapon agents and commercially available technologies now permit the large-scale production of bioweapon agents in small-scale facilities at relatively low cost. Failures in the detection and containment of bioweapon and emerging disease outbreaks among populations of wildlife and indigenous peoples in developing countries could result in severe erosion of genetic diversity in local and regional populations of both wild and domestic animals, the extinction of endangered species and the extirpation of indigenous peoples and their cultures. Our ability to understand and control the spread of diseases within and among human and animal populations is increasing but is still insufficient to counter the threats presented by existing bioweapon diseases and the growing number of highly pathogenic emergent infections. Interdisciplinary and international efforts to increase the monitoring, surveillance, identification and reporting of disease agents and to better understand the potential dynamics of disease transmission within human and animal populations in both industrialised and developing country settings will greatly enhance our ability to combat the effects of bioweapons and emerging diseases on biological communities and biodiversity.

Surveillance and monitoring of wildlife diseases.

It is now recognised that those countries which conduct disease surveillance of their wild animal populations are more likely to detect the presence of infectious and zoonotic diseases and to swiftly adopt counter measures. The surveillance and monitoring of disease outbreaks in wildlife populations are particularly relevant in these days of rapid human and animal translocation, when the contact between wild and domestic animals is close and the threat of a bioterrorist attack is very real. The authors describe the problems inherent in wildlife disease surveillance and stress the importance of the establishment of national strategies for disease detection. The various sampling methods employed for monitoring outbreaks of disease and mortality in wildlife populations are discussed and their strengths and weaknesses described. A major advantage of an efficient disease monitoring programme for wildlife is the early detection of new and 'emerging' diseases, some of which may have serious zoonotic and economic implications. The authors conclude that wildlife disease monitoring programmes that are integrated within national animal health surveillance infrastructures should have the capacity to respond promptly to the detection of unusual wildlife mortality and to institute epizootiological research into new and emerging wildlife diseases.

Plasma alpha-tocopherol, beta-carotene, and lipid levels in semi-free-ranging Przewalski horses (Equus przewalskii).

Circulating concentrations of alpha-tocopherol, beta-carotene, and lipids were quantified in 19 Przewalski horses (Equus przewalskii) inhabiting the steppes of Ukraine during June 1991. Foals (n = 3) had lower mean plasma alpha-tocopherol (4.7 micrograms/ml) and beta-carotene (0.3 microgram/ml) levels than did adults (n = 16; 6.6 and 0.7 micrograms/ml, respectively) and higher mean cholesterol concentrations (1.42 vs. 0.98 mg/ml). Mean triglyceride levels did not differ between foals and adults (0.46 mg/ml). Alpha tocopherol concentrations were substantially higher than those considered normal for domestic and zoo equids, but beta-carotene, cholesterol, and triglyceride levels were within expected ranges. These limited data suggest excellent circulating vitamin E concentrations in these horses and may provide useful comparative guidelines for assessment of fat-soluble nutrient concentrations and establishment of optimal dietary management of Przewalski horses.

Disease risks associated with wildlife translocation projects.

Translocation is defined as the movement of living organisms from one area for free release in another. Throughout the world, increasing numbers of native and exotic species are translocated every year. Most of these movements involve native mammals, birds and fish, and are made by private and national wildlife agencies to augment existing populations, usually for sporting purposes. The translocation of endangered species, often to reintroduce them into a part of the historical range from which they have been extirpated, has also become an important conservation technique. The success of potentially expensive, high-profile wildlife translocation projects depends to a large extent on the care with which wildlife biologists and their veterinary advisers evaluate the suitability of the chosen release site, and on the ability of the translocated animals to colonise the area. The veterinary aspects of reintroduction projects are proving to be of extreme importance. There are already instances of inadequate disease risk assessment resulting in expensive failures and, worse still, the introduction of destructive pathogens into naive resident wildlife populations. In this paper, some of the disease risks attending wildlife translocation projects are described and suggestions are made for the development of systematic procedures to reduce these risks both at the source of the founder animals and at the proposed release site.

Field studies on animal trypanosomiasis in Mozambique. I. Effectiveness of the prophylactic drugs isometamidium chloride and pyrithidium bromide.

The efficacy of the trypanocides Samorin and Prothidium to protect beef cattle in areas of different trypanosome challenge was studied in Muabsa, Mozambique during an 18 month period. The performance of two groups of 1.5- to 3-year old bulls was observed, the first group in an area of high tsetse density, the second in an area of low to medium tsetse density. Glossina morsitans and G. pallidipes were present and their respective densities were determined using standard fly rounds, a mobile electric screen and biconical traps. The trypanosome challenge was determined using parameters of tsetse density and infection rates; the trypanosome risk was determined by Berenil Indices in both groups of animals. The Berenil Indices in the two study areas were not significantly different despite a great difference in apparent densities of the tsetse flies. The period of protection afforded by Samorin and Prothidium was similar in both areas which would appear to indicate that the tsetse density had no apparent effect on the degree of challenge. Samorin gave a slightly better protection than Prothidium as shown by a lower frequency of infections as well as higher packed cell volumes. There was no difference in growth rates between the treatment groups and study areas during the entire study period. It was concluded that in the study area Samorin usage is preferable to that of Prothidium. Tsetse densities obtained from standard fly rounds were found unsatisfactory in assessing the challenge, possibly because this method does not sample all components of the population. The Berenil Index, however, was found to be a useful indicator of trypanosome risk and thus frequency of treatment required.

Tuberculosis in wildlife in the Ruwenzori National Park, Uganda (Part II).

The results of post-mortem examinations of 90 warthog (Phacochoerus aethiopicus) conducted in the Ruwenzori National Park, Uganda during a survey of tuberculous infection in wildlife are described. Nine per cent of warthog were found to show gross lesions on autopsy and of these organisms which could by typed, Mycobacterium bovis was isolated in 2 of 6 cases and 5 atypical mycobacterial strains were isolated from the remaining 4. The distribution and character of the lesions is described and it is concluded that the route of infection in the warthog is alimentary. A mycobacterial survey of 8 other species of mammals, 7 species of birds, 5 species of fish and 1 species of amphibian is described. None of the mammals (except possibly 1 elephant), birds, fish or amphibia is described. None of the mammals (except possibly 1 elephant), birds, fish or amphibia was found to be infected with M. bovis but several individuals were found to harbour atypical, probably saprophytic, mycobacterial types. The origin of tuberculosis in buffalo and warthog in the Ruwenzori National Park is discussed and is concluded to have been previous contact with domestic cattle.

Tuberculosis in wildlife in the Ruwenzori National Park Uganda (part I).

The technique adopted for a survey of tuberculous infection in wild Cape buffalo (Syncerus caffer, Sparrman) living in the Ruwenzori National Park, Uganda is described and the results of gross post-mortem examinations of a random sample of 52 buffalo and a selected sample of 64 thin buffalo are tabulated. Tuberculosis was found to occur in buffalo in the area of the Park north of the Maramagambo Forest; the disease is considered to be absent from the area south of the forest. Tuberculosis was found to affect 10% of the random sample of buffalo and 38% of the selected thin sample. Laboratory procedures carried out for the isolation and typing of the mycobacteria are described. Mycobacterium bovis was shown to be responsible for 12 of 14 infections and atypical mycobacteria for the remaining two. The distribution and character of the lesions are described and an account of the epidemiology, morbidity and mortality of the disease is given. It is estimated that tuberculosis is responsible for an annual mortality of about 1% of the 18,000 buffalo inhabiting the Park.

Experimental transmission of gastro-intestinal nematodes between sheep (Ovis aries) and Thomson's gazelles (Gazella thomsonii).

Experimental cross-transmission of gastro-intestinal nematodes between Merino sheep (Ovis aries) and Thomson's gazelles (Gazella thomsonii) from similar but separate grazing habitats in Kenya was studied. Cross-transmission did occur with some species but the faecal egg counts of sheep were higher than the gazelles' following infection with larvae isolated from either sheep or gazelles. Of the 11 gastro-intestinal nematodes which became established in gazelles following infection with larvae cultured from nematodes in gazelles, only Haemonchus contortus, Trichostrongylus probolurus and Cooperia hungi were infective for sheep. Following infection with larvae of either sheep or gazelle origin, the H. contortus recovered from the sheep at necropsy were more numerous and had greater average weights, lengths and spicule lengths than those recovered from the gazelles. This would suggest that H. contortus is primarily a sheep parasite. It is concluded that Thomson's gazelles probably would not contribute significantly to the problem of haemonchosis in sheep in areas of shared grazing, unless efforts were being made to eradicate the parasite from sheep, in which case the gazelles would act as a continuing reservoir of infection.

Blood characteristics of the African elephant (Loxodonta africana cyclotis).

Mean corpuscular volume, hematocrit, hemoglobin concentration and red and white cell counts from five domesticated African elephants were measured. The results obtained are tabulated and compared with those from shot and chemically immobilized African elephants.

Linoleic acid and linolenic acid elongation products in muscle tissue of Sncerus caffer and other ruminant species.

The metabolic elongation products of both linoleic acid and linolenic acid were found in muscle tissues of Syncerus caffer and other ruminants. The acids with four double bonds were predominantly in the linoleic acid series, whereas the higher degrees of unsaturation, mainly five double bonds, were in the linolenic acid series. The total linoleic acid and linolenic acid groups were present in the relative proportions of about 4:1, in contrast with the fish oils, where the acids are mainly in the linolenic acid series. The consistent occurrence of members of both groups of acids in the animals studied here suggests to us that both may be important for structural purposes.