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Biomedical subjects

L Karstad

Publications and source records attributed to L Karstad.

At least 37 records · Page 2Linked to original sources

Serologic evidence of toxoplasmosis in captive and free-living wild mammals in Kenya.

Sera from 27 captive and 132 free-living mammals in Kenya were tested for antibodies to Toxoplasma by the Sabin-Feldman dye test. Of these 8 of 8 (100%) captive carnivores, 14 of 19 (74%) captive herbivores, 11 of 14 (79%) free-living carnivores and 97 of 118 (82%) free-living herbivores were found to have Toxoplasma antibodies. The feeding and drinking habits of the various herbivore species were considered as possibly facilitating exposure to Toxoplasma oocysts; also the feeding on prey in the wild and on meat in captivity as favoring exposure to the cyst form of Toxoplasma.

Animals↗

Antibodies to malignant catarrhal fever virus antigens in the sera of normal and naturally infected cattle in Kenya.

Six different serological tests were used to examine Kenyan cattle sera for antibodies to the herpesvirus of malignant catarrhal fever. Significantly higher levels of indirect immunofluorescent antibody to early and late virus antigens and of complement fixing antibody were found in the sera of 13 naturally infected cattle than in 482 sera collected from four different groups of normal cattle. Virus neutralising and immunoprecipitating antibodies were also found in some infected cattle sera but not in normal cattle sera. Many non-specific reactions occurred using counterimmunoelectrophoresis. These preliminary results indicate that the serological diagnosis of wildebeest-associated malignant catarrhal fever may be possible.

Animals↗

Isolation of bovine malignant catarrhal fever virus from ocular and nasal secretions of wildebeest calves.

Malignant catarrhal fever (MCF) virus was isolated from ocular secretions of four out of nine free-ranging wildebeest calves, while four out of 11 animals had the virus in nasal secretions. The mean infectivity of virus in ocular and nasal secretions was 10(2.25)TCID50/ml and 10(2.5)TCID50/ml respectively but infectivity of more than 10(3.2)TCID50/ml was found in some ocular and nasal secretions. Thus it appears that MCF virus is excreted via the ocular and nasal routes from wildebeest calves, and the presence of high titre virus supports the suggestion that MCF virus is disseminated by these secretions. This virus was not recovered from urine or saliva.

Animals↗

Fatal theileriosis in eland (Taurotragus oryx): pathology of natural and experimental cases.

Clinical, parasitological and pathological studies were made on five eland infected with Theileria. Three were natural Theileria infections while the other two were experimental cases. All eland died. Generalised lymph node enlargement was a common feature. Wasting occurred in the more prolonged cases and in two of the field cases severe terminal diarrhoea developed. The third field case died in severe respiratory distress. In all cases, up to 50 per cent piroplasm parasitaemia was wound and schizonts were seen in lymph node biopsy samples and in lymphoid smears prepared at necropsy. These parasites showed the morphological characteristics of Theileria taurotragi. The cells parasitised by schizonts had the morphological features of large lymphoid cells. These were infiltrated widely throughout the tissues and organs examined including the lymphoid organs, the gastrointestinal tract (in two cases this was the cause of death), adrenal glands, liver, lungs and to a lesser extent the heart and kidneys. In the one case in which the brain was examined, it was found to be involved. The severely affected organs were diffusely infiltrated with parasitised cells both intravascularly and extravascularly. Lymphocytolysis, necrosis, thrombosis and haemorrhage were frequently encountered in association with parasitised cells. All eland involved except one were males despite the fact that there were more females in the herds.

Adrenal Glands↗

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.

Animals↗

Observations on the epidemiology of the herpesvirus of infectous bovine rhinotracheitis/infectious pustular vulvovaginitis in wildebeest.

Spontaneous vulvovaginitis erupted in wildebeest (Connochaetes taurinus) after betamethasone inoculation. Infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV) is probably a venereal disease because virgin wildebeest did not develop vulvovaginitis after betamethasone injections, nor was the virus transmitted to these virgin wildebeest and steers which were in pen contact with the affected animals. A domestic bovine heifer developed mild IPV and became a virus carrier, when exposed to the wildebeest IPV virus by vaginal instillation.

Animals↗

Experimental infection of wildebeest with the herpesvirus of infectious bovine rhinotracheitis/infectious pustular vulvovaginitis.

Intravaginal inoculation of a wildebeest (Connochaetes taurinus) with a wildebeest strain of the infectious bovine rhinotracheitis/infectious pustular vulvovaginitis herpesvirus induced only mild vulvovaginitis. The same virus did not produce any disease in another wildebeest exposed intranasally. A wildebeest bull which was inoculated by preputial instillation developed mild posthitis. The virus was reisolated only from the sites of inoculation. A carrier state was initiated in a wildebeest inoculated only once, intravaginally. The presence of this virus in the various secretions is a potential source for venereal transmission.

Animals↗

Experiments on the Babesia bigemina carrier state in East African buffalo and eland.

Three captive East African buffalo (Syncerus caffer) were injected with 5 x 109 bovine erythrocytes with Babesia bigemina pathogenic for cattle. None of the buffalo showed signs of disease, but Babesia were found in blood smears for four days indicating their multiplication. The carrier state of Babesia bigemina was established in two buffalo for 28 and 147 days respectively by sub-inoculation into splenectomized calves, while no parasites were demonstrated 28 days after injection in the third buffalo. Two buffalo shot in Kenya did not appear to be carriers of Babesia gibemina, as shown by sub-inoculation of blood in splenectomized calves. Two captive eland (Taurotragus oryx) were inoculated and their blood investigated as with the experimental buffalo. Neither eland appeared to harbour Babesia bigemina 28 days after injection, even though one was splenectomized. The experimental data indicate that the East African buffalo can be a carrier of Babesia bigemina for at least 5 months, while this parasite did not survive in eland. Buffalo may play a role in the epidemiology of babesiosis in cattle, while eland most likely do not.

Animals↗

The prevalence of antibody of antibody to contagious caprine pleuropneumonia (Mycoplasma strain F38) in some wild herbivores and camels in Kenya.

Sera of 11 species of wild herbivores were tested for antibody to Mycoplasma strain F38 which causes contagious caprine pleuropneumonia (CCPP) in Kenya. Antibodies were found in buffalo (Syncerus caffer) (32%), impala (Aepyceros melampus) (10%) and camels (Camelus dromedarius) (49%) but not in bushbuck (Tragelaphus scriptus), eland (Taurotragus oryx), Grant's gazelle (Gazella granti), kongoni (Alcelaphus buselaphus cokei), oryx (Oryx beisa), Thomson's gazelle (Gazella thomsonii), waterbuck (Kobus defassa) and wildebeest (Connochaetus taurinus).

Animal Population Groups↗

Skin papillomas in an impala (Aepyceros melampus) and a giraffe (Giraffa camelopardalis).

Viral particles, typical of the papovavirus family, were demonstrated by electronmicroscopy in small papillomas found on the feet of an impala (Aepyceros melampus) and on the face of a giraffe (Giraffa camelopardalis) in Kenya. Histologically the tissues proved to be typical papillomas. The viral particles measured 38 nm and 40 nm in diameter in all tissue sections from the impala and giraffe respectively.

Animals↗

Viruses isolated from captive and free-ranging wild ruminants in Alberta.

Nasal secretions, leukocytes and preputial or vaginal swabs from a group of 15 captive wild ruminants, comprising six pronghorn antelope (Antilocapra americana), seven fallow deer (Dama dama) and two mule deer (Odocoileus hemionus), and from 50 free-ranging pronghorns in southern Alberta, were examined for viral agents. Captive animals were given injections of dexamethasone daily for 6 days in attempts to reactivate latent infections. Specimens were collected at 2-3 day intervals from days 0 to 18. Free-ranging pronghorns were sampled only once, at the time of capture. Fifteen viral isolates were obtained from the animals: six isolates of parainfluenza 3 (PI3) from nasal swabs from one fallow deer and one mule deer; five isolates of herpesvirus from leukocytes, vaginal, preputial and nasal swabs from three fallow deer; and four isolates of PI3 from nasal secretions of the 50 free-ranging pronghorns.

Alberta↗

Poxvirus fibromas on African hares.

Small dermal tumors were found on three African hares (Lepus capensis) in the Laikipia District, Kenya. Gross and histopathologic studies revealed similarities to the Shope's fibroma of wild rabbits in North America and fibromas of European hares. Histological examination of the African hare fibromas revealed intracytoplasmic inclusion bodies characteristic of poxviruses and poxvirus virions were demonstrated by electron microscopy of ultrathin sections. Attempts to propagate the virus in rabbit skin, embryonated chicken eggs and cell cultures were unsuccessful.

Animals↗

Organochlorine poisoning of ring-billed gulls in southern Ontario.

Clinical, necropsy, bacteriologic, parasitologic, histopathologic, toxicologic and animal inoculation studies suggest that organochlorine (PBC, dieldrin and DDE) poisoning was an important factor in causing deaths of free-flying ring-billed gulls (Larus delawarensis) in southern Ontario in 1969 and 1973. The brains of gulls dying with clinical signs of neurologic involvement, and dead gulls with no other apparent cause of death, contained organochlorine residues of significantly greater levels than those found in healthy gulls shot for comparison.

Animals↗

Experience with drugs for capture and restraint of wildebeest, impala, eland and hartebeest in Kenya.

Two hundred and sixteen wildebeest (Connochaetes taurinus), 111 impala (Aepyceros melampus), 39 eland (Taurotragus oryx) and 9 hartebeest (Alcelaphlus buselaphus cokii) were drug-immobilized for capture or for handling in captivity. Drugs used for capture were combinations of xylazine, etorphine and acepromazine, or xylazine and fentanyl, with or without the addition of azaperone. For restraint in captivity, xylazine alone proved to be satisfactory in most instances. Drugs were injected with projectile syringes. Recommendation on dosage are given.

Acepromazine↗

Tuberculosis in lesser flamingoes in Kenya.

Four cases of tuberculosis are recorded in lesser flamingoes (Phoeniconaias minor) from Lake Nakuru, Kenya. The clinical, pathological and microbiological findings are given and the possible significance of the infection in this species is discussed.

Animals↗

Hepatitis in skunks caused by the virus of infectious canine hepatitis.

Two cases of acute, fatal, hepatitis occurred in young, striped skunks (Mephitis mephitis) trapped in southern Ontario. Histologically, lesions in the liver were similar to infectious canine hepatitis. A virus was isolated which produced large intranuclear inclusions in dog kidney cell cultures. These inclusions were Feulgen-positive and fluoresced green with acridine orange stain. The skunk hepatitis isolate was identified as the virus of infectious canine hepatitis by virus neutralization tests.

Adenoviruses, Canine↗