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Theileriosis (Cytauxzoonosis) in Roan antelope (Hippotragus equinus): Field exposure to infection and identification of potential vectors
2012
Johan C.A. Steyl | Leon Prozesky | Wilhelm H. Stoltsz | John A. Lawrence
Four hand-reared, naïve roan antelope, 4 months of age, were exposed to naturally infected pasture on a game farm in Mpumalanga Province, South Africa, where roan are known to die from theileriosis. Various clinical parameters were recorded during this period. The predominant ticks parasitising these animals at the time (January to February), were Rhipicephalus appendiculatus and Rhipicephalus evertsi evertsi adults. After a period of 5 weeks the animals developed signs of clinical theileriosis and were treated with buparvaquone to prevent mortality. Primary hyperplasia of the local draining lymph nodes (Lnn. anorectales) near the feeding site of adult R. evertsi evertsi indicated possible transmission of Theileria sp. (sable) by this tick species. After recovery from theileriosis, these animals were confirmed carriers of Theileria sp. (sable) by PCR (polymerase chain reaction) and DNA probe analysis. Laboratory-bred larvae and nymphs of R. evertsi evertsi and R. appendiculatus respectively, were fed on the ears of these roan antelope. Salivary glands from moulted and prefed adult ticks of each species were dissected and stained for Theileria spp., and the PCR and DNA probe applied to a representative batch of dissected glands. R. appendiculatus adults collected from grass in infected camps were also dissected after prefeeding them on rabbits. Salivary glands of both tick species showed infected acini on staining and were also positive for Theileria sp. (sable) only, on multiprotozoal PCR-screening analysis. There was no statistical significant difference between the infection rate and the intensity of infection between the two tick species. R. appendiculatus ticks collected from grass were also PCR-positive for Theileria sp. (sable).
Mostrar más [+] Menos [-]Epidemiological perspectives of ticks and tick-borne diseases in South Sudan: Cross-sectional survey results
2012
Fredrick M. Kivaria | Angolwisye M. Kapaga | Gabriel K. Mbassa | Paul F. Mtui | Rhombe J. Wani
A cross-sectional study was conducted between September and October 2010 in five states of South Sudan that were selected on the basis of the perceived risk of tick-borne diseases. The purpose was to investigate epidemiological parameters of tick-borne diseases in South Sudan and their uses in future control strategies. A total of 805 calves were assessed by clinical, microscopic and serological examination and tick counts. The indirect Enzyme-Linked Immuno-Sorbent Assay (ELISA) was used to detect antibodies to<em> Theileria parva</em>, <em>Theileria mutans</em>, <em>Anaplasma marginale</em> and <em>Babesian bigemina</em>. Sero-conversion risks for <em>T. parva</em> and <em>T. mutans</em> were 27.3% and 31.3% respectively, whilst the risk was 57.6% and 52.8% for <em>A. marginale</em> and <em>B. bigemina</em>, respectively. Major tick species identified include <em>Rhipicephalus appendiculatus</em>, <em>Rhipicephalus decoloratus</em>, <em>Rhipicephalus microplus</em>, <em>Amblyomma variegatum</em>, and <em>Rhipicephalus evertsi</em>. There was great variation (<em>P</em> ≤ 0.001) in the number of all these ticks, both between herds in a state and between calves in an individual herd. The low and intermediate sero-conversion risks observed in the study states suggest that immunisation against East Coast fever (ECF) is justified. Fortunately, three major genotypes that were identified by applying Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCRRFLP) analysis on the p104 to the blood samples and T. parva Muguga, matched very well with <em>T. parva</em> Kiambu 5 and <em>T. parva</em> Muguga; therefore the Muguga cocktail can be used for the immunisation of cattle in South Sudan. However, prospective studies are required to develop optimal control measures for tick-borne diseases under different ecological and husbandry practices in South Sudan.
Mostrar más [+] Menos [-]The dynamics of questing ticks collected for 164 consecutive months off the vegetation of two landscape zones in the Kruger National Park (1988–2002). Part II. Rhipicephalus appendiculatus and Rhipicephalus zambeziensis
2011
Arthur M. Spickett | Gordon J. Gallivan | Ivan G. Horak
The study aimed to assess the long-term population dynamics of questing Rhipicephalus appendiculatus and Rhipicephalus zambeziensis in two landscape zones of the Kruger National Park (KNP). Ticks were collected by dragging the vegetation monthly in three habitats (grassland, woodland and gully) at two sites in the KNP (Nhlowa Road and Skukuza) from August 1988 to March 2002. Larvae were the most commonly collected stage of both species. More R. appendiculatus were collected at Nhlowa Road than at Skukuza, with larvae being most abundant from May to August, while nymphs were most abundant from August to December. Larvae were most commonly collected in the gullies from 1991 to 1994, but in the grassland and woodland habitats from 1998 onwards. Nymphs were most commonly collected in the grassland and woodland. More R. zambeziensis were collected at Skukuza than at Nhlowa Road, with larvae being most abundant from May to September, while nymphs were most abundant from August to November. Larvae and nymphs were most commonly collected in the woodland and gullies and least commonly in the grassland (p < 0.01). The lowest numbers of R. appendiculatus were collected in the mid-1990s after the 1991/1992 drought. Rhipicephalus zambeziensis numbers declined after 1991 and even further after 1998, dropping to their lowest levels during 2002. The changes in numbers of these two species reflected changes in rainfall and the populations of several of their large herbivore hosts, as well as differences in the relative humidity between the two sites over time.
Mostrar más [+] Menos [-]Observations on the transmission of Theileria mutans in South Africa
1981
De Vos, A.J. | Roos, J.A.
Theileria mutans, 4 isolates obtained from geographically distant parts of South Africa by subinoculation of infected blood were readily transmitted to cattle by Amblyomma hebraeum, all attempts to transmit these isolates with Rhipicephalus appendiculatus were unsuccessful
Mostrar más [+] Menos [-]The ecology of Rhipicephalus zambeziensis and Rhipicephalus appendiculatus (Acarina, Ixodidae) with particular reference to Zimbabwe
1982
Norval, R.A.I. | Walker, J.B. | Colborne, J.
Rhipicephalus zambeziensis and R. appendiculatus from Zimbabwe, ecology of species compared with reference to host records, geographical distribution, physiography, climate, and seasonal occurrence, sex and stage of recovered parasites; additional review information on hosts and distribution of R. zambeziensis throughout its range in Africa
Mostrar más [+] Menos [-]The comparative prevalence of five ixodid tick species infesting cattle and goats in Maputo Province, Mozambique
2009
De Matos, C.(Instituto de Investigação Agrária de Mozambique ,University of Pretoria Faculty of Veterinary Science Department of Veterinary Tropical Diseases) | Sitoe, C.(Instituto de Investigação Agrária de Mozambique) | Neves, L.(Universidade Eduardo Mondlane Faculdade de Veterinária) | Nöthling, J.O.(University of Pretoria Faculty of Veterinary Science Department of Production Animal Studies) | 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)
Clarification of the status of Rhipicephalus kochi Donitz, 1905 (Ixodoidea, Ixodidae)
1983
Clifford, C.M. | Walker, J.B. | Keirans, J.E.
Rhipicephalus kochi, synonymy, description of female, male, nymph, and larva, scanning electron microscopy, brief report of laboratory life cycle study, review of host records and zoogeography in Africa, differentiation from R. pravus, R. punctatus, and R. appendiculatus
Mostrar más [+] Menos [-]Rhipicephalus zambeziensis sp. nov., a new tick from eastern and southern Africa, together with a redescription of Rhipicephalus appendiculatus Neumann, 1901 (Acarina, Ixodidae)
1981
Walker, J.B. | Norval, R.A.I. | Corwin, M.D.
Rhipicephalus zambeziensis n. sp., all stages of life cycle compared with life cycle of R. appendiculatus, redescription of R. appendiculatus, attempts to cross breed these 2 species in laboratory were unsuccessful thus validating their taxonomic separation, the 2 species can live sympatrically
Mostrar más [+] Menos [-]Effects of anti-tick cocktail vaccine against Rhipicephalus appendiculatus
2008
Imamura, S.(Hokkaido Univ., Sapporo (Japan)) | Konnai, S. | da Silva Vaz, I.Jr. | Yamada, S. | Nakajima, C. | Ito, Y. | Tajima, T. | Yasuda, J. | Simuunza, M. | Onuma, M. | Ohashi, K.
Rhipicephalus appendiculatus serpin-3 (RAS-3), R. appendiculatus serpin-4 (RAS-4) and a 36kDa immuno-dominant protein of R. appendiculatus (RIM36) were reported as candidate antigens for the anti-tick vaccine to control ixodid ticks. In the present study, we generated recombinant proteins of RAS-3 (rRAS-3), RAS-4 (rRAS-4) and RIM36 (rRIM36), and assessed their potency as an anti-tick cocktail vaccine in cattle model. RT-PCR analysis showed that RAS-3, RAS-4 and RIM136 transcripts were detected in both adult male and female ticks during feeding. Immunization of cattle with the combination of rRAS-3, rRAS-4 and rRIM36 had raised antibodies against all recombinants and anti-sera had reacted with the molecules from the tick salivary gland extract. Tick infestation challenge demonstrated protective immunity against female ticks, resulting in mortality rates of 39.5 and 12.8 % for the vaccinated and control groups, respectively. Moreover, the mortality rate of Theileria parva-infected female ticks was 48.5 and 10.8 % in the vaccinated and control group, respectively. In order to evaluate the levels of pathogen transmission capacity by T. parva-infected ticks fed on immunized cattle, the occurrence of T. parva in the bovine parotid lymph node and peripheral blood was also determined and quantified by real-time PCR. Although the infection with T. parva could not be protected by the vaccine, the occurrence of pathogen in peripheral blood was delayed 1 to 2 days after the infestation challenge in vaccinated group. These results suggest that this cocktail vaccine plays a role in the prevention of tick infestation.
Mostrar más [+] Menos [-]Exposure to cattle immunized with different stocks of Theileria parva to buffalo-associated Theileria challenge on two game parks in Zimbabwe
2001
Latif, A.A. (Midrand Univ., Halfway House (South Africa). Faculty of Science) | Hove, T. | Kanhai, G.K. | Masaka, S.