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Biomedical subjects

J M Pletcher

Publications and source records attributed to J M Pletcher.

At least 19 recordsLinked to original sources

Assessment of the histopathological lesions and chemical analysis of feral cats to the smoke from the Kuwait oil fires.

Twenty-six adult or subadult feral cats were collected from Kuwait approximately 8 months after the ignition of the Kuwait oil wells. These animals were obtained from two sources: 12 animals from Kuwait City, a relatively smoke-free area, and 14 from the city of Ahmadi, an area with heavy smoke. Animals were euthanized and a complete set of tissues consisting of all major organs was taken for histopathology. Samples of lung, liver, kidney, urine, and blood were also taken for toxicology. Histopathological lesions observed in the lung were mild accumulations of anthracotic pigment in the lungs of 17 cats. Hyperplasia of the bronchial and bronchiolar gland in 8 cats, and smooth muscle hyperplasia of bronchioles in 14 cats. Tracheal gland hyperplasia was observed in 7 cats, and minimal squamous metaplasia of the tracheal mucosa in 17 cats, Laryngeal lesions consisted of submucosal gland hyperplasia in 2 cats and squamous metaplasia of the mucosa in 5 cats. Hyperplasia of the nasal submucosal glands was observed in 6 animals. The pharyngeal mucosa as well as other organs and organ systems were normal in all cats. Atomic absorption analysis for 11 metals was performed; vanadium and nickel levels (two metals that were present in the smoke from the oil fires) are not indicative of substantial exposure to the oil fires. Based on the histopathological findings and toxicological analysis, it is felt that inhalation of air contaminated with smoke from the oil fires had little or no long-term effect on the animals examined.

Animals↗

Histopathologic lesions in sea otters exposed to crude oil.

Following the Exxon Valdez oil spill in Prince William Sound, Alaska, sea otters (Enhydra lutris) that appeared to be contaminated with oil, that were in danger of becoming contaminated, or that were behaving abnormally were captured and taken to rehabilitation centers. Exposure to oil was assessed by visual examination when otters arrived at the centers. Degree of oil exposure was graded according to the following criteria: oil covering greater than 60% of the body--heavily contaminated; oil covering 30-60% of the body--moderately contaminated; oil covering less than 30% of the body or light sheen on fur--lightly contaminated. If there was no oil visible, otters were considered uncontaminated. Tissues from 51 oil-contaminated sea otters (14 males, 37 females) and from six uncontaminated sea otters (three males, three females) that died in rehabilitation centers were examined histologically. Among oil-contaminated sea otters, 19/46 had interstitial pulmonary emphysema, 13/40 had gastric erosion and hemorrhage, 11/47 had centrilobular hepatic necrosis, 14/47 had periportal to diffuse hepatic lipidosis, and 10/42 had renal tubular lipidosis. Of the uncontaminated sea otters, 1/6 had gastric erosion and hemorrhage and 1/6 had diffuse hepatic lipidosis. Histologic examinations were performed on tissues from five sea otters (three males, two females) found dead with external oil present 15 to 16 days after the spill. Periportal hepatic lipidosis and renal tubular lipidosis were found in 3/5, and interstitial pulmonary emphysema was found in 1/5. Tissues from six apparently normal sea otters (four males, two females) collected from an area not affected by an oil spill were examined histologically, and none of these lesions were found. We conclude that interstitial pulmonary emphysema, centrilobular hepatic necrosis, and hepatic and renal lipidosis of sea otters were associated with exposure to crude oil. Gastric erosion and hemorrhage may have been associated with stress of captivity and/or oil exposure.

Animals↗

Hepatic lesions associated with Cooperioides hepaticae (Nematoda: Trichostrongyloidea) infection in impala (Aepyceros melampus) of the Kruger National Park.

Intrahepatic biliary lesions were observed in two of 12 lambs, seven of 12 yearlings and 10 of 25 adult impala (Aepyceros melampus) surveyed in the Kruger National Park, Republic of South Africa. Lesions were associated with the nematode Cooperioides hepaticae, a trichostrongyloid parasite that inhabits the bile ducts of impala, and ranged from a mild chronic-eosinophilic cholangitis to foci of florid hyperplastic cholangitis with duct ectasia. The latter almost always contained viable worms and, after the worms died, the lesions appeared as foreign-body granulomas. Infection was acquired early in life; severe lesions were seen most frequently in yearlings. Adults were less severely infected, which suggested an acquired immunity. Although the incidence of infection was high, cooperiiasis did not appear to be a serious herd-health problem at the time of this study.

Animals↗

A new filarial nematode (Onchocercidae) from warthogs (Phacochoerus aethiopicus) of the Kruger National Park.

Fifty-five warthogs [Phacochoerus aethiopicus (Suidae: Artiodactyla)] from the Kruger National Park, Republic of South Africa, were examined for parasites. Adult filarial nematodes were found in lymphatic vessels adjacent to peripheral and visceral lymph nodes, and microfilariae were found in lymph nodes and circulating blood. Both the adult parasite and the microfilaria are described. Specific identification is pending confirmation and recovery of intact adult specimens and microfilariae identical to those described herein.

Animals↗

Nodular abomasitis in impala (Aepyceros melampus) caused by the nematode Longistrongylus sabie.

The periodic occurrence of nodular abomasitis associated with the trichostrongylid nematode Longistrongylus sabie was observed in impala lambs of the Kruger National Park, Republic of South Africa. The condition was seen predominantly in animals less than 1 yr of age. Peak incidences occurred in the spring and fall, when more than 50% of the lambs studied had from several to numerous nodules in their abomasal mucosae. The nodular lesions in the lambs were macroscopically larger than, but microscopically similar to, those observed in domestic ruminants with ostertagiosis; however, L. sabie worm burdens were much lower than those in clinical cases of ostertagiosis, and no evidence of diarrhea could be found in any of the lambs studied. The physical condition of lambs with moderate to severe nodular abomasitis did not differ noticeably from that of lambs with mild involvement or those without lesions. Nodular abomasitis caused by this parasite was of minimal significance to impala herds in the Park under the circumstances prevailing at the time of the study.

Abomasum↗

Copper deficiency in piglets characterized by spongy myelopathy and degenerative lesions in the great blood vessels.

Copper deficiency was diagnosed in piglets from a farm in the Transvaal. The mortality rate among 5 to 8-week-old piglets had been sporadic but considerably high over a 12 month period. Affected animals showed signs of ataxia, posterior paresis, horizontal nystagmus, inability to stand and front and hind limb paddling movements. Death ensued from 3-5 days after the onset of clinical signs. A paucity of myelin in the spinal cord and degenerative lesions involving elastic fibres of the aorta and pulmonary artery were detected. Tissue copper levels were low in both clinically affected and unaffected piglets on the farm, and the copper content of the diet fed to sows and growing piglets was considered inadequate. The lesions related to copper deficiency are described with emphasis on those in the spinal cord and great blood vessels, and the pathologic processes resulting in hypocupraemic lesions are considered.

Animals↗

Studies on Strongylus asini. I. Experimental infestation of equines.

Infective larvae were harvested from a culture of eggs collected from adult Strongylus asini recovered from a free-ranging Burchell's zebra, Equus burchelli, in the Kruger National Park. Worm-free zebra, horse and donkey foals were successfully infested, but infestation failed in a mule foal. At slaughter, 117-125 days post-infestation, S. asini in their 4th moult were recovered from the liver and portal veins. This is the first report of successful experimental infestation of these hosts with S. asini.

Animals↗