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Biomedical subjects

B D Perry

Publications and source records attributed to B D Perry.

At least 37 records · Page 2Linked to original sources
PubMed1988

A baiting system suitable for the delivery of oral rabies vaccine to dog populations in Zimbabwe.

A baiting system suitable for the delivery of oral rabies vaccine to dog populations in developing countries was studied in Zimbabwe. In a field trial, 369 sponge baits containing a placebo liquid, rhodamine B as a biomarker and a pungent attractant were distributed over an area of 60 sq km in a communal land in Manicaland with a dog population of over 500. Twenty-four hours later 21 per cent of the baits were recovered and 79 per cent of these had been significantly bitten or chewed. Twenty-five per cent of the dogs examined showed evidence of superficial staining by rhodamine B indicating that they had chewed baits or ingested their contents. It was concluded that the system would deliver an oral vaccine to dog populations more efficiently than had been the case in comparable studies in wildlife populations, but that the number of baits per unit area should in future studies be increased.

Administration, Oral↗
PubMed1988

Epidemiology of bovine babesiosis and anaplasmosis in Zambia.

The serological prevalence of bovine babesiosis and anaplasmosis in the traditional farming sector of six provinces of Zambia was determined using the indirect fluorescent antibody test (IFAT) for babesiosis and the card agglutination test (CAT) for anaplasmosis. Antibodies to Babesia bigemina occurred throughout the country whereas the prevalence of B. bovis followed the distribution of its tick vector Boophilus microplus which is limited to the north-eastern part of the country. Low numbers of B. bovis serologically positive cattle were demonstrated in central and southern Province. Anaplasma spp. occurred throughout Zambia but the overall percentages of positive sera were low ranging between 14.7% and 38.6% using the CAT. Two hundred sera were retested for anaplasmosis using an enzyme-linked immunosorbent assay (ELISA). Sero-prevalence rates were 1.5 to 2.3-fold greater with the ELISA than with the card agglutination test.

Agglutination Tests↗
PubMed1988

The design and use of supportive epidemiologic studies.

Structured investigation of disease outbreaks or deviations from desired productivity levels do not always lead to definitive answers upon which intervention programs can be based. There is an important role for well-designed supportive epidemiologic studies to supplement outbreak investigations, and the circumstances of their use are described in this article. The design of cross-sectional, case-control, and cohort studies is also discussed, and procedures for data analysis are provided.

Animals↗
PubMed1988

The distribution of African swine fever virus isolated from Ornithodoros moubata in Zambia.

African swine fever (ASF) has been reported in the Eastern Province of Zambia since 1912 and is now considered to be enzootic there. A survey of the distribution of ASF virus in Zambia was carried out by virus isolation from Ornithodoros moubata ticks collected from animal burrows in National Parks and Game Management Areas in northern, eastern, central and southern Zambia. ASF virus was isolated from ticks in all areas examined. The prevalence of infection in O. moubata was between 0.4% in South Luangwa National Park and 5.1% in Livingstone Game Park and mean infectious virus titres ranged from 10(3.4) HAD50/tick in Kakumbe Game Management Area to 10(5.9) HAD50/tick in Chunga and Nalusanga Game Management Areas. The prevalence of infection in adult ticks was between 4.7% and 5.3% in all areas examined except Sumbu National Park and Livingstone Game Park, where the prevalence was 15.1% and 13.2% respectively in adult ticks. The ratio of infected females to males for all the infected adult ticks in all areas of Zambia was 3.2:1.

African Swine Fever↗
PubMed1988

Horse-baited insect trap and mobile insect sorting table used in a disease vector identification study.

A horse-baited trap and a mobile insect sorting table were used to conduct an arthropod survey for potential vectors of Potomac Horse Fever in southern Maryland and northern Virginia. The trap and table worked effectively for the live collection and sorting of haemophagous Diptera such as: Simulium spp., Stomoxys calcitrans, Musca autumnalis, Tabanus spp. and Chrysops spp. during the diurnal collections periods, and Culicoides spp. during the crepuscular periods. The trap was not as convenient for live collection of mosquito species during the nocturnal period. Modifications to the trap design was suggested for mosquito live trapping.

Animals↗
PubMed1987

Rabies.

The practicing veterinarian has a key role to play in rabies control in the maintenance of protection in the companion animal populations, in the education of the pet-owning community on rabies, and in the decision-making process that accompanies human exposure to potentially rabid animals. This role encompasses far more than the routine maintenance of health and well-being in pet animal populations. Although it is important to remain diligent in the immunization of domestic pets against rabies to provide a barrier between wildlife, the main reservoir of infection, and man, it is also important to be aware of the current trends in wildlife rabies within a region. Research is currently underway to investigate methods of immunizing wildlife populations, but the effective and widespread control of rabies in these species is still a long way off; in the meantime, there will be an increasing demand for practicing veterinarians to take the lead in the control of this most fearful zoonotic disease.

Animals↗
PubMed1986

Ecology and phenology of ticks in Zambia: seasonal dynamics on cattle.

A study of the seasonality and infestation rates of ticks was carried out in 11 cattle herds in different ecological habitats in Zambia between 1980 and 1982. Wherever possible supplementary data were obtained from opportunistic collections from cattle and other hosts. Analysis of over 1000 tick collections from cattle indicated that infestation rates of the most important species, Amblyomma variegatum and Rhipicephalus appendiculatus vary in different ecological habitats: (i) In Western Province, infestations are much lower than elsewhere; (ii) in Central and Southern Provinces, moderate to high infestations occur; and (iii) in Eastern Province, R. appendiculatus numbers are generally low and A. variegatum numbers are moderate. These two species, however, have similar life cycles throughout their range with one generation per year. Larvae occur mainly from March to May, nymphae from May to September, and adults of A. variegatum from October to December and of R. appendiculatus from December to April. Boophilus decoloratus appears to have two to four generations per year but is uncommon during the rainy season. In some areas in central Zambia Rhipicephalus compositus adults are seasonally common in September-October whereas Rhipicephalus evertsi is more or less ubiquitous. Low to moderate infestations of Hyalomma truncatum and Hyalomma rufipes occur in most areas. At least 14 other less common or rare species of Rhipicephalus, Amblyomma, Haemaphysalis and Ixodes were taken infrequently from cattle. These and other host-specific species were also collected from dogs, sheep, various wildlife hosts and the environment. Infestation rates, seasonality and host-relationships of tick species are discussed in relation to their ecology. Relevant biosystematic and disease relationships are reviewed briefly. The baseline data derived from this study are adequate for integrated analysis with those from other ecological and economic investigations to formulate tick control strategies.

Animals↗
PubMed1986

Enterocolitis caused by Ehrlichia sp. in the horse (Potomac horse fever).

Potomac horse fever was reproduced in 15 ponies by transfusion of whole blood originally from two natural cases and subsequently from ponies infected by the transfusions. Incubation periods varied from 9 to 15 days. Affected ponies developed varying degrees of fever, diarrhea, anorexia, depression, and leukopenia. Eleven affected ponies were killed, three died in the acute phase of the disease, and one did not show clinical signs. The most consistent post-mortem findings were fluid contents in the cecum and large colon, and areas of hyperemia (of inconstant degree and distribution) in mucosae of both small and large intestines. Multifocal areas of necrosis occurred in mucous membranes. Ehrlichial organisms were most common in the cytoplasm of epithelial cells, macrophages, and mast cells of the large colon.

Animals↗
PubMed1985

Measuring the benefits of disease control: relationship between herd structure, productivity and health.

The influence of calving percentage and mortality levels on herd structures is studied. Standard herd structures with set levels of mortality are calculated for comparison with field data. Herd structures from field surveys in Zambia are studied in order to determine how these can be used to gain more information about herd input and output dynamics. Methods of calculating off-take and the problems relating to making such calculations are discussed.

Age Factors↗
PubMed1985

Ultrastructural study of ehrlichial organisms in the large colons of ponies infected with Potomac horse fever.

Potomac horse fever is characterized by fever, anorexia, leukopenia, profuse watery diarrhea, dehydration, and high mortality. An ultrastructural investigation was made to search for any unusual microorganisms in the digestive system, lymphatic organs, and blood cells of ponies that had developed clinical signs after transfusion with whole blood from horses naturally infected with Potomac horse fever. A consistent finding was the presence of rickettsial organisms in the wall of the intestinal tract of these ponies. The organisms were found mostly in the wall of the large colon, but fewer organisms were found in the small colon, jejunum, and cecum. The organisms were also detected in cultured blood monocytes. In the intestinal wall, many microorganisms were intracytoplasmic in deep glandular epithelial cells and mast cells. Microorganisms were also found in macrophages migrating between glandular epithelial cells in the lamina propria and submucosa. The microorganisms were round, very pleomorphic, and surrounded by a host membrane. They contained fine strands of DNA and ribosomes and were surrounded by double bileaflet membranes. Their ultrastructure was very similar to that of the genus Ehrlichia, a member of the family Rickettsiaceae. The high frequency of detection of the organism in the wall of the intestinal tract, especially in the large colon, indicates the presence of organotrophism in this organism. Infected blood monocytes may be the vehicle for transmission between organs and between animals. The characteristic severe diarrhea may be induced by the organism directly by impairing epithelial cell functions or indirectly by perturbing infected macrophages and mast cells in the intestinal wall or by both.

Animals↗
PubMed1985

Causative ehrlichial organisms in Potomac horse fever.

An ehrlichia was consistently isolated from the peripheral blood leukocyte fraction of ponies that had been experimentally infected with Potomac horse fever by whole blood transfusion from naturally infected horses. The organism was propagated in a human histiocyte cell line for 3 to 5 weeks and then inoculated intravenously or intradermally into healthy adult ponies. Clinical signs of Potomac horse fever, which varied in the degree of severity, occurred 9 to 14 days post-inoculation in all of the ponies. One pony died 20 days post-inoculation. The ehrlichial organism was reisolated in the human histiocyte cell line from the blood leukocyte fraction of all of the experimental ponies on each day that samples were examined (days 9, 10, 11, 19, and 39). These organisms were identical to those originally detected in the wall of the intestine of ponies with clinically diagnosed Potomac horse fever when compared by light and electron microscopy and an immunofluorescence labeling technique. The immunofluorescent antibody titer became positive in a pony at 20 days postinjection. These results indicate that the ehrlichial organisms is the causative agent of Potomac horse fever.

Animals↗
PubMed1985

Babesia odocoilei Emerson and Wright, 1970 in white-tailed deer, Odocoileus virginianus (Zimmermann), in Virginia.

Pooled blood samples from six white-tailed deer from the Great Dismal Swamp in Virginia were inoculated into two splenectomized deer. A moderately severe clinical reaction ensued, characterized by a hemolytic anemia, and a Babesia found in both recipient animals was presumptively identified as B. odocoilei. This is the first reported identification of this parasite in white-tailed deer in Virginia.

Animals↗