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Biomedical subjects

R A Kock

Publications and source records attributed to R A Kock.

At least 19 recordsLinked to original sources

Re-infection of wildlife populations with rinderpest virus on the periphery of the Somali ecosystem in East Africa.

We report surveillance for rinderpest virus in wildlife populations in three major ecosystems of East Africa: Great Rift Valley, Somali and Tsavo from 1994 to 2003. Three hundred and eighty wild animals were sampled for detection of rinderpest virus, antigen or genome and 1133 sampled for antibody in sera from Kenya, Uganda, Ethiopia and Tanzania from 20 species. This was done modifying for wildlife the internationally recommended standards for rinderpest investigation and diagnosis in livestock. The animals were selected according to susceptibility and preference given to gregarious species, and populations were selected according to abundance, availability and association with livestock. Rinderpest virus, antigen and/or genome were detected in Kenya; within Tsavo, Nairobi and Meru National Parks. Serological results from 864 animals (of which 65% were buffalo) from the region were selected as unequivocal; showing the temporal and spatial aspects of past epidemics. Recent infection has been only in or peripheral to the Somali ecosystem (in Kenya). Our evidence supports the hypothesis that wildlife is not important in the long-term maintenance of rinderpest and that wildlife are infected sporadically most likely from a cattle source, although this needs to be proven in the Somali ecosystem. Wildlife will continue to be a key to monitoring the remaining virus circulation in Africa.

Africa, Eastern↗

Scabies in free-ranging mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda.

Between August and December 1996, there was an outbreak of a debilitating skin disease attributed to Sarcoptes scabiei infection in mountain gorillas (Gorilla beningei beringei) in Bwindi Impenetrable National Park in Uganda. All four members of a gorilla group which had been habituated to tourists were clinically affected; the infant male gorilla was most severely affected and died, the juvenile male showed serious manifestations of the disease and the two adult animals showed milder signs. The three older animals recovered after a single intramuscular dose of ivermectin. S scabiei mites were observed on skin scrapings and biopsies taken while the juvenile was immobilised and in postmortem samples taken from the infant. The clinical signs did not recur during the following year, and no other gorilla groups in the park were observed to be clinically affected.

Animals↗

Infectious animal diseases: the wildlife/livestock interface.

The long-standing conflict between livestock owners and animal health authorities on the one hand, and wildlife conservationists on the other, is largely based on differing attitudes to controlling diseases of livestock which are associated with wildlife. The authors have attempted to highlight the fact that these disease problems are frequently bi-directional at the wildlife/livestock interface. The different categories of diseases involved are presented. A new dimension being faced by veterinary regulatory authorities is the spectre of emerging sylvatic foci of diseases, such as bovine tuberculosis, bovine brucellosis and possibly rinderpest; these diseases threaten to undermine national and international eradication schemes, which have been implemented and executed with significant success, and at great cost. Conversely, wildlife-based ecotourism world-wide has expanded rapidly over the past decade and is the source of lacking foreign revenue for many developing countries. Traditional subsistence farming is still the largest source of much-needed protein on some continents and this, together with the growth and hunger of historically disadvantaged communities for land, is forcing enterprises and communities with markedly different objectives and land-use practices to operate effectively in close proximity. Some land-users rely exclusively on wildlife, others on livestock and/or agronomy, while yet others need to combine these activities. The net result may be an expansion or intensification of the interface between wildlife and domestic livestock, which will require innovative control strategies that permit differing types of wildlife/livestock interaction, and that do not threaten the land-use options of neighbours, or the ability of a country to market animals and animal products profitably.

Animals↗

Rinderpest epidemic in wild ruminants in Kenya 1993-97.

A severe epidemic of rinderpest, affecting mainly wild ruminants, occurred between 1993 and 1997 in East Africa. Buffalo (Syncerus caffer), eland (Taurotragus oryx) and lesser kudu (Tragelaphus imberbis) were highly susceptible. The histopathological changes, notably individual epithelial cell necrosis with syncytia formation, were consistent with an infection with an epitheliotrophic virus. Serology, the polymerase chain reaction, and virus isolation confirmed the diagnosis and provided epidemiological information. The virus was related to a strain which was prevalent in Kenya in the 1960s, of a second lineage (II), and distinct from isolations of rinderpest virus in the region since 1986. The source of the virus was presumed to be infected cattle from the Eastern region of Kenya and Somalia. The pathogenicity of the virus varied during the epidemic. The mortality in buffalo populations was estimated to be up to 80 per cent, and population data suggested that the virus had an adverse effect on a wide range of species. The virus caused only a mild disease in cattle, with minimal mortality. The results confirmed the importance of wildlife as sentinels of the disease, but although wildlife were important in the spread of the virus, they did not appear to act as reservoirs of infection.

Animal Diseases↗

Mycobacterium avium-related epizootic in free-ranging lesser flamingos in Kenya.

An epizootic in free-ranging lesser flamingos (Phoeniconaias minor) in Kenya resulted in more than 18,500 deaths from August through mid-November 1993. Disease was concentrated along the shores of Rift Valley Lakes Bogoria and Nakuru (Kenya) and did not involve any of the other avian or mammalian species frequenting the lakes. Coincidental to the outbreak was a bloom of algae on Lake Bogoria, toxins from which were first suspected to be causative. Discrete necrotic and granulomatous lesions were often noted in spleen and liver, and Mycobacterium avium serovar I was isolated from both organs. Escherichia coli and Pseudomonas aeruginosa also were often recovered in pure culture from liver. Gross and histopathological evaluation of the cases disclosed signs of acute sepsis and also chronic, potentially life-threatening lesions of mycobacteriosis, primarily involving the spleen and liver. Lesions typical for algae toxicosis were not seen in any birds. Deaths were attributed to septicemia complicated in those affected, by mycobacteriosis.

Animals↗

Effects of translocation on hematologic parameters of free-ranging black rhinoceros (Diceros bicornis michaeli) in Kenya.

Management of the endangered black rhinoceros (Diceros bicornis michaeli) in Africa frequently involves translocation. These procedures are not without risk, and protocols must be critically examined. Hematologic analyses can be used to evaluate the effects of translocation on animal health. Hematologic data obtained during routine translocation of free ranging black rhinoceros (n = 74) in Kenya between 1991 and 1995 were examined, and subsets of data from rhinoceros (n = 43) that were translocated to different regions of Kenya were compared. All animals showed an increase in total blood protein. Animals transported for longer periods and to lower altitude zones with higher ambient temperatures and trypanosomiasis developed anemia and showed neutrophilia, lymphopenia (males), and eosinopenia. The changes in packed cell volume (PCV), hemaglobin, and neutrophils were more marked in females, and the PCV drop was more significant in subadults. The red cell changes were most probably pathologic, involving the loss of red cells from circulation through sequestration or hemorrhage. The changes in white cell parameters are consistent with the effect of endogenous corticosteroids as a result of stress. Transport and confinement stress might lead to gastric ulceration with hemorrhage. In many animals, exposure to trypanosomes contributes to anemia.

Anemia↗

Haematology of clinically normal and sick captive reindeer (Rangifer tarandus).

A retrospective analysis of haematological values from clinically normal captive reindeer (Rangifer tarandus) showed that the red cell count, haemoglobin level, packed cell volume and lymphocyte count were higher and the erythrocyte sedimentation rate and eosinophil count were lower in juveniles than in adults. Newborn animals were anaemic compared with juveniles and adults and had high reticulocyte counts. The values from healthy reindeer were used to identify abnormal haematological variations in a number of sick animals. It was shown that reindeer exhibit similar haemopathological responses to those of other artiodactyla, with increases in the erythrocyte sedimentation rate and fibrinogen level being of particular diagnostic significance. Eosinophilia was the only abnormal haematological finding in individuals with subclinical infections of intestinal parasites.

Animals↗

Physiological effects of etorphine, acepromazine and xylazine on the black fallow deer (Dama dama).

Confined and unconfined fallow deer (Dama dama) of the black variety kept at Whipsnade Park were sedated with etorphine in combination with acepromazine, or xylazine or both, with or without atropine. Induction, sedation and recovery times were recorded. During the period under sedation, systemic and pulmonary arterial pressures, electrocardiographs, body temperature, arterial blood gas pressures and pH, packed cell volume and plasma electrolytes and enzymes were monitored. In both groups, and with all drug combinations, heart rates (except where atropine was used and respiratory rates were depressed, pulmonary arterial pressures were elevated, and blood oxygen tension and pH lowered compared with interspecies norms. In confined animals, systemic arterial pressures were depressed. Unconfined animals and animals in which atropine was used showed higher and more varied systemic arterial pressures and more varied heart rates. Cardiac arrests occurred in eight animals, five during induction and three during sedation, one of which was revived with oxygen. Severe arrhythmia occurred in an animal in which atrioventricular block was confirmed and reversed by oxygen treatment.

Acepromazine↗

Physiological effects of etorphine, acepromazine and xylazine in the scimitar horned oryx (Oryx dammah).

Scimitar horned oryx (Oryx dammah), kept under confined and unconfined conditions were immobilised with etorphine in combination with acepromazine or xylazine or both, and with xylazine alone. Both groups of animals were successfully sedated with etorphine and xylzine, with or without acepromazine, although hypothermia and mild hypoxaemia and a fall in packed cell volume were frequently noted. Xylazine alone produced a dose dependent degree of sedation in semitame subadult animals kept in confinement, but only slight depression in their wild, unconfined counterparts. If xylazine was not included in the immobilising mixture induction was traumatic and full sedation not achieved. Heart rates and arterial pressures (systemic and pulmonary) were also monitored but no remarkable changes were noted. The only abnormalities in blood biochemistry were raised aspartate transminase and creatine kinase. Ruminal regurgitation could be a major problem if endotracheal intubation was not achieved early in the procedure.

Acepromazine↗

The use of two mixtures of ketamine and xylazine to immobilise free ranging Bennetts wallabies.

Two mixtures of ketamine and xylazine were evaluated as immobilising agents for the capture of free ranging Bennetts wallabies (Protemnodon rufogrisea). The wallabies were given either a dose of 150 mg ketamine and 187.5 mg xylazine (mixture 1), or a dose of 160 mg ketamine and 80 mg xylazine (mixture 2) by intramuscular injection using a projectile syringe. The quality of induction and immobilisation was similar with both mixtures, although immobilisation occurred more rapidly and lasted longer with mixture 1. Respiration was not depressed and blood gas levels were not significantly changed from normal. Bradycardia was produced but no other arrhythmias were recorded. There was a slight fall in mean arterial pressure. Cloacal temperature was not altered to a significant degree. Recovery was good in the unstimulated animal and no side effects were observed. Mixture 1 was preferred owing to its more rapid immobilising effect.

Animals↗

Remote injection systems: science and art.

The development, practice and potential of remote injection systems are reviewed and the legislation pertinent to the possession and use of darting equipment and immobilising drugs is summarised. The available rifles, pistols, blow-guns and syringes are critically examined in terms of their accuracy with a flexible dart volume, their impact and injection trauma and their efficiency of use, durability, economy and safety. Future developments in remote injection technology are dependent on many factors including welfare, advances in immobilising agents and methods and, most significantly, on demand. The central role of the veterinary profession in the use of remote injection systems is emphasised.

Animals↗

Obstructive urethral calculi in the male camel: report of two cases.

Two cases of obstructive urethral calculi in the male dromedary camel are reported. Infection, metabolic disorders, malnutrition and climatic stress are cited as possible causes. The diagnosis and the surgical treatment of this condition are discussed, with particular reference to the anatomy of the camel's penis.

Animals↗