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History of bluetongue research at Onderstepoort
2009
Verwoerd, D.W.(University of Pretoria Faculty of Veterinary Science)
Research on this economically important disease of ruminants, especially sheep, which had been named bluetongue by farmers in the 19th century, has been part and parcel of the activities at Onderstepoort ever since its establishment in 1908 and therefore covers a full century of the OVI's existence. In view of Onderstepoort's centenary celebration a brief overview of this research is given in terms of the historic milestones which influenced and guided global research on this and other viral diseases of animals.
Show more [+] Less [-]Veterinary education in Africa: Current and future perspectives
2009
Swan, G.E.(University of Pretoria Faculty of Veterinary Science) | Kriek, N.P.J.(University of Pretoria Faculty of Veterinary Science)
Veterinary education commenced in South Africa in 1920 at the Onderstepoort Veterinary Institute in South Africa in association with the Transvaal University College, now the University of Pretoria. Sir Arnold Theiler, Director of Veterinary Research and Education, was the first Dean. Today there are 46 veterinary training institutions in Africa of which 21 are in sub-Saharan Africa. Veterinary services are indispensable to the sustained health and wellbeing of animals and humans, and agricultural economies of countries worldwide. Veterinary education, postgraduate training, and research, and adequate numbers of veterinarians, are essential to satisfy the millennium development goals, the objectives of NEPAD and the African Union, and the agreements regulating international trade. The relevance of the veterinary profession internationally is currently subject to profound scrutiny. Its contributions are assessed against major environmental, demographic, political, disease, technological and economic needs. The scope of veterinary training in future will have to emphasise veterinary public health, food safety, emerging diseases, international trade, bioterrorism, and biomedical research, within the context of a one-health system focusing on the interface between wildlife, domesticated animals, humans, and their environment. Within the context of time available, it would mean reducing the time allocated to training in the field of companion animals. A brief history and scope of veterinary education; current international trends in veterinary education and provisioning; and some perspectives on future veterinary training and initiatives applicable to Africa are provided.
Show more [+] Less [-]Field services: Eradication and control of animal diseases
2009
Modisane, B.M.(Disaster Management and Veterinary Services National Department of Agriculture)
Prevention, eradication and control of animal diseases, as well as public health assurance are major functions of veterinary authorities. The strategies to control animal diseases differ from disease to disease but are often similar on a disease basis from country to country depending on the main objective of the measure employed. These measures include among others movement control and quarantine, vaccination, treatment and mass slaughtering. However, not every country uses all these control measures at the same time. A combination of measures may be employed to avoid spreading of the disease from infected to clean animals and success is dependent on a variety of factors, including the strength and capacity of the veterinary services, cross border efforts for disease surveillance, political will, diagnostic facilities and financial support.
Show more [+] Less [-]Molecular monitoring of African swine fever virus using surveys targeted at adult Ornithodoros ticks: A re-evaluation of Mkuze Game Reserve, South Africa
2009
Arnqt, L.F.(University of Pretoria Department of Zoology and Entomology Mammal Research Institute,University of Pretoria Faculty of Veterinary Science Department of Paraclinical Sciences) | Du Toit, J.T.(University of Pretoria Department of Zoology and Entomology Mammal Research Institute,Utah State University Department of Wildland Resources) | Bastos, A.D.S.(University of Pretoria Department of Zoology and Entomology Mammal Research Institute,ARC-Onderstepoort Veterinary Institute)
The Mkuze Game Reserve (MGR), in north-eastern KwaZulu-Natal Province, South Africa is an African swine fever virus (ASF) controlled area. In a survey conducted in 1978, ASF prevalence in warthogs and Ornithodoros ticks in MGR was determined to be 2 % and 0.06 %, respectively. These values, acknowledged as being unusually low compared to other East and southern African ASF-positive sylvatic-cycle host populations, have not been assessed since. The availability of a sensitive PCR-based virus detection method, developed specifically for the sylvatic tampan host, prompted a re-evaluation of ASF virus (ASFV) prevalence in MGR ticks. Of the 98 warthog burrows inspected for Ornithodoros presence, 59 (60.2 %>) were found to contain tampans and tick sampling was significantly male-biased. Whilst gender sampling-bias is not unusual, the 27 °% increase in infestation rate of warthog burrows since the 1978 survey is noteworthy as it anticipates a concomitant increase in ASFV prevalence, particularly in light of the high proportion (75 %>) of adult ticks sampled. However, despite DNA integrity being confirmed by internal control amplification of the host 16S gene, PCR screening failed to detect ASFV. These results suggest that ASFV has either disappeared from MGR or if present, is localized, occurring at exceptionally low levels. Further extensive surveys are required to establish the ASFV status of sylvatic hosts in this controlled area.
Show more [+] Less [-]The role of the World Organisation for Animal Health (OIE) to facilitate the international trade in animals and animal products
2009
Brückner, G.K.(World Organisation for Animal Health)
The international trade in animals and animal products has become a sensitive issue for both developed and developing countries by posing an important risk for the international spread of animal and human pathogens whilst at the same time being an essential activity to ensure world-wide food security and food safety. The OIE has since its founding in 1924, applied a democratic and transparent decision-making process to continuously develop and review international standards for animal health and zoonoses to facilitate trade in animals and animal products. The role of the OIE is also mandated by the World Trade Organization (WTO) as international reference point for standards related to animal health. In support of its overall objective of promoting animal health world-wide, the OIE has also launched several other initiatives such as the improvement of the governance of veterinary services within its member countries and territories and to enhance the availability of diagnostic and scientific expertise on a more even global geographical distribution. Several trade facilitating concepts such as country, zonal and compartment freedom from disease as well the trade in disease free commodities has been introduced to enhance the trade in animals and animal products for all its members including those from developing and transitional countries who are still in the process of enhancing to full compliance with international sanitary standards.
Show more [+] Less [-]Ecological parameters of Lamproglena hoi (Copepoda: Lernaeidae) infection on the Bushveld smallscale yellowfish, Labeobarbus polylepis (Boulenger, 1907)
2009
Austin, A.(University of Johannesburg Department of Zoology) | Avenat-Oldewage, A.(University of Johannesburg Department of Zoology)
This study describes the distribution and aspects of the ecology of Lamproglena hoi. Bushveld small-scale yellowfish, Labeobarbus polylepis (Boulenger, 1907) were collected during June 2006 from the Phongolo and Assegaai rivers, March 2005 and October 2006 from the Elands River, and January 2007 and June 2008 from the Komati River in Mpumalanga, South Africa and examined for the presence of parasites. Lamproglena hoi specimens were collected from the gill filaments of the host. Specimens were fixed with warm AFA (alcohol-formaldehyde-acetic acid) and preserved in 70 % ethanol. The identification of parasites took place in the laboratories of the University of Johannesburg. Twenty-five copepods (prevalence 21 %, mean intensity = 4.17, abundance = 0.86) were collected on 29 fish in the Phongolo River and 46 copepods (prevalence 40 %, mean intensity = 3.83, abundance = 1.53) were collected on 30 fish in the Assegaai River. One hundred and sixty eight copepods (prevalence 52 %, mean intensity = 12.92, abundance = 6.72) were collected on 25 fish in 2005, and 527 copepods (prevalence 95 %, mean intensity = 27.74, abundance = 26.35) were collected on 20 fish in the Elands River. One hundred and sixteen copepods (prevalence 75 %, mean intensity = 7.73, abundance = 5.80) were collected on 20 fish in 2007, and 273 copepods (prevalence 63 %, mean intensity = 16.06, abundance = 10.11) were collected on 27 fish in 2008 in the Komati River. Labeobarbus polylepis from these four rivers was found to have a relatively high L. hoi infection. Inseminated L. hoi females (immature) attach to the host in winter and their ovaries become conspicuous (mature). In spring fertilized eggs are stored in egg sacs hanging from the body (gravid), indicating that fertilized eggs start to hatch in spring and continued hatching into summer. Parasites prefer the median part of the second gill arch for attachment. No correlation exists between the number of parasites recorded on the gills and the sizes (total lengths) of yellowfish sampled.
Show more [+] Less [-]Species composition and geographic distribution of ticks infesting cattle, goats and dogs in a temperate and in a subtropical region of south-east Africa
2009
Horak, I.G.(University of Pretoria Faculty of Veterinary Science Department of Veterinary Tropical Diseases,University of the Free State Department of Zoology and Entomology) | Nyangiwe, N.(Döhne Agricultural Development Institute ,University of Pretoria Faculty of Veterinary Science Department of Veterinary Tropical Diseases) | De Matos, C.(Instituto de Investigação Agrária de Mozambique ,University of Pretoria Faculty of Veterinary Science Department of Veterinary Tropical Diseases) | Neves, L.(Universidade Eduardo Mondlane Faculdade de Veterinária)
The species and distribution of ticks infesting cattle, goats and dogs in the eastern region of the Eastern Cape Province, South Africa and Maputo Province, Mozambique were determined from collections made from these animals at 72 localities in the former region and 30 in the latter. Eleven ixodid and one argasid species were recovered in the Eastern Cape Province and 15 ixodid species in Maputo Province. The most common ticks infesting cattle and goats in both provinces were Amblyomma hebraeum, Rhipicephalus (Boophilus) microplus, Rhipicephalus appendiculatus and Rhipicephalus evertsi evertsi. The dominant species on dogs were Haemaphysalis elliptica and Rhipicephalus simus. The geographic distributions of the major species and some of the minor species in both regions were plotted. The partial or complete displacement of the indigenous tick Rhipicephalus (Boophilus) decoloratus by the introduced species R. (B.) microplus was a major feature of both surveys.
Show more [+] Less [-]Description and comparison of the pupae of a further two Culicoides (Avaritia) species from the dung of large herbivores in South Africa (Diptera: Ceratopogonidae)
2009
Nevill, Hilda | Nevill, E.M. | Venter, G.J.(ARC-Onderstepoort Veterinary Institute)
In 2007 Nevill, Venter, Meiswinkel & Nevill demonstrated that the pupae of five Culicoides species belonging to the Imicola complex of the subgenus Avaritia could readily be differentiated from one another using various morphological characters. Three of the described species, Culicoides bolitinos Meiswinkel 1989; Culicoides loxodontis Meiswinkel 1992 and Culicoides sp. # 107 (= C. kwagga, Meiswinkel, unpublished thesis 1995), were reared from the dung of large herbivores, which included buffaloes, elephants, white and black rhinoceroses and zebras. However, during that study a further two Avaritia species, neither of which belonged to the Imicola complex, were reared from dung and these are the subject of the present study. For the past 20 years the adults of these two new closely related species have been known as Culicoides sp. # 54 pale form (p.f.) Meiswinkel and Culicoides sp. # 54 dark form (d.f.) Meiswinkel. The taxonomic description and formal naming of the adults of these two species has yet to be done. The present description and comparison of their pupae show that they are two clearly distinct species; that there is no group of morphological characters that can be used to differentiate these two species from the previously described five species of the Imicola complex; and finally that there was no difference between the pupae of C. sp. # 54 d.f. nor C. sp. # 54 p.f. reared from the dung of different host animals.
Show more [+] Less [-]Study on the efficacy and safety of different antigens and oil formulations of infectious coryza vaccines containing an NAD-independent strain of Avibacterium paragallinarum
2009
Dungu, B.(Onderstepoort Biological Products) | Brett, B.(Onderstepoort Biological Products) | Macdonald, R.(Onderstepoort Biological Products) | Deville, S.(SEPPIC) | Dupuis, L.(SEPPIC) | Theron, J.(University of Pretoria Department of Microbiology and Plant Pathology) | Bragg, R.R.(University of the Free State)
The present study was designed to assess and compare three different formulations of the new Onderstepoort infectious coryza (IC) quadrivalent vaccine, which contain an NAD-independent strain of Avibacterium paragallinarum (previously known as Haemophilus paragallinarum), and a commercial IC vaccine, not containing an NAD-independent strain, for their safety and ability to protect chickens of varying ages against virulent challenges with four different serovars of A. paragallinarum, including the NAD-independent strain of the C-3 serovar. Four groups of 140 chickens each were vaccinated at the age of 17 weeks and revaccinated at the age of 19 weeks with each of the four vaccine formulations. A similar sized group of non-vaccinated chickens was used as control. Two rounds of challenge were conducted: a group of chicken in each vaccination group was challenged between 31 and 35 weeks of age, while another group was challenged between 51 and 55 weeks of age. The "in-contact" challenge model was used in this experiment. For each vaccination group, the four challenge strains representing four local serovars were used in each challenge round. The efficacy of the vaccines was compared based on overall protection levels obtained and the duration of protection. The safety of the different vaccines was determined by the severity of post-vaccination reactions. The need for the incorporation of the NAD-independent strain in the vaccine was evidenced by the low protection level against NAD-independent challenge recorded in the group of birds vaccinated with the commercial vaccine. The results obtained confirmed not only the variation in virulence of different South African serovars, with serovar C-3 being the most virulent and serovar B having almost no virulence but also the age related increase in susceptibility. The importance of a suitable formulation of the vaccine is discussed.
Show more [+] Less [-]Blood platelet counts, morphology and morphometry in lions, Panthera leo
2009
du Plessis, L.(University of Pretoria Faculty of Veterinary Science Department of Anatomy and Physiology)
Due to logistical problems in obtaining sufficient blood samples from apparently healthy animals in the wild in order to establish normal haematological reference values, only limited information regarding the blood platelet count and morphology of free-living lions (Panthera leo) is available. This study provides information on platelet counts and describes their morphology with particular reference to size in two normal, healthy and free-ranging lion populations. Blood samples were collected from a total of 16 lions. Platelet counts, determined manually, ranged between 218 and 358 x 10(9)/l. Light microscopy showed mostly activated platelets of various sizes with prominent granules. At the ultrastructural level the platelets revealed typical mammalian platelet morphology. However, morphometric analysis revealed a significant difference (P < 0.001) in platelet size between the two groups of animals. Basic haematological information obtained in this study may be helpful in future comparative studies between animals of the same species as well as in other felids.
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