Parasites of domestic and wild animals in South Africa. XXIII. Helminth and arthropod parasites of warthogs, Phacochoerus aethiopicus, in the eastern Transvaal Lowveld

A total of 69 warthogs, Phacochoerus aethiopicus, were collected from 4 localities within the Kruger National Park, eastern Transvaal Lowveld. These animals harboured 16 nematode species, 2 trematodes, 1 or 2 species of adult cestodes and the larval stages of 4 cestodes. No pattern of seasonal abundance could be determined for any of the helminths. The warthogs were also infested with 3 flea species, 1 louse species, 8 ixodid tick species, 1 argasid tick and the nymphae of a pentastomid. The seasonal abundance of fleas of the genus Echidnophaga, of the sucking louse Haematopinus phacochoeri and the ixodid ticks Amblyomma hebraeum, Rhipicephalus appendiculatus, Rhipicephalus simus and Rhipicephalus zambeziensis was determined.     

The transstadial transmission of Babesia caballi by Rhipicephalus evertsi evertsi

Rhipicephalus evertsi evertsi larvae were fed on the ears of rabbits. Seven days after larval infestation, unfed, newly moulted nymphae were manually removed to infest a splenectomized donkey showing a patent Babesia caballi infection. Engorged nymphae were collected from the donkey and the ensuing adult ticks were placed on a susceptible horse. The horse contracted a B. caballi infection showing a prepatent period of 19 days after tick infestation. A very low parasitaemia, (highest score 2), which was patent for only 10 days, was recorded. The lowest packed cell volume recorded was 16%.     

Comparison of the pneumopathogenicity of two strains of bovine viral diarrhea virus

The pneumopathogenicity in calves of 2 strains of bovine viral diarrhea (BVD) virus, isolate 2724 (a noncytopathogenic virus) and isolate 72 (a cytopathogenic virus), was compared. All calves were inoculated endobronchially, using fiberoptic bronchoscopy. Two calves were given Pasteurella haemolytica, 2 calves were given the noncytopathogenic BVD virus, and 2 calves were given cytopathogenic BVD virus. Five calves were inoculated sequentially with BVD virus and, 5 days later, with P haemolytica. Two of these calves were inoculated with the noncytopathogenic BVD virus and the other 3 with the cytopathogenic strain. Both BVD virus strains caused marked respiratory tract disease in the calves sequentially inoculated with P haemolytica and also impaired pulmonary clearance of P haemolytica. However, the effect of the cytopathogenic strain was more severe than the noncytopathogenic strain, indicating that strains of BVD virus may vary in their pneumopathogenicity for calves.     

Isolation of bovine herpesvirus-1 from vesicular lesions of the bovine udder

Bovine herpesvirus-1 was isolated from vesicular lesions on the udder and mammary papillae (teats) of a Charolais cow. Lesions on the animal consisted of papules and vesicles up to 10 mm in diameter. The virus was identified by fluorescent antibody and serum-neutralization tests.     

The genome of anaplasma: DNA base composition and DNA/DNA hybridization

The Tm value of DNA from Anaplasma centrale and Anaplasma marginale was found to be 87.1 degrees C and 89.3 degrees C, respectively. The G + C content, calculated from the Tm, was 45.1% for A. centrale and 48.5% for A. marginale. Identical hybridization patterns were obtained when the DNA from one species was hybridized to restriction endonuclease-digested DNA from the other species.     

Some toxic, physical and chemical properties of the oral secretion of the sand tampan, Ornithodoros savignyl Audouin (1827).

Mice, exposed to the effects of the oral secretion of Ornithodorus savignyi by injection, revealed that a potent toxin is present in the secretion. Electrophoretic and chromatographic separations of the secretion showed a heterogeneous pattern of protein-like substances. Toxicity trials on these fractions showed that the toxic principle is protein in nature and fairly heat stable.     

Frequency of occurrence of viruses associated with respiratory tract disease of cattle in Oklahoma: serologic survey for bovine herpesvirus DN599.

Serum samples from 351 Oklahoma cattle were tested for antibodies to DN599 virus by the indirect fluorescent antibody test. Seven cattle (approximately 2%) were seropositive for this virus.     

Use of the indirect fluorescent antibody test in the detection of bovine respiratory syncytial virus antibodies in bovine serum.

The indirect fluorescent antibody test was adapted for identifying bovine respiratory syncytial virus and its specific antibody, using goat turbinate (GTU) cells. The virus caused maximal cytopathic effects in GTU cells 4 to 8 days postinfection, but fluorescence was not readily detected during this period. Fluorescence was maximal in infected GTU cells at 24 to 36 hours postinfection, but could be detected 48 hours postinfection. Bovine serums (331) which had been submitted to the Oklahoma Animal Disease Diagnostic Laboratory were tested for antibodies to this virus, and 73.6% were found to be positive.     

Evaluation of a TaqMan real-time PCR for the detection of Theileria parva in buffalo and cattle

A real-time PCR assay based on TaqMan probe chemistry was developed for the detection of Theileria parva DNA in blood samples. It uses a Theileria genus-specific PCR primer set and a T. parva-specific probe to amplify and hybridize with a species-specific part of the 18S rRNA gene of the parasite. The test was evaluated using positive and negative reference blood samples and shown to be specific for T. parva. Analytical sensitivity was determined by testing a dilution series of T. parva positive blood. It was shown to be able to detect parasitaemia as low as 2 × 10(-6)%. The Taqman assay results were also compared with that obtained with the real-time hybridization probe PCR assay, which is currently employed as the official test for the diagnosis of T. parva infections in buffalo and cattle and was shown to be equally sensitive. A panel of 1164 field samples was screened using both assays and 164 samples tested positive in both tests, indicating a good correlation.     

Estimating grass fuel loads with a disc pasture meter in the Kruger National Park

Abstract

The major portion of the fuel load in the savanna areas comprises surface fuels in the form of the standing grass sward. The disc pasture meter was successfully calibrated for estimating grass fuel loads in the main landscapes of the Kruger National Park. The calibration comprised estimating the mean disc height of a 4 m² quadrat and harvesting the grass as close to ground level as possible. Using a large quadrat gave highly satisfactory results indicating that this procedure should be considered as a standard method of calibration, particularly in grass swards having a low basal cover.