The authors highlight the reliance on repeated natural infections by tickborne pathogens to maintain immunity in immunized herds. That incidence of clinical heartwater in cattle, caused by Cowdria ruminantium, is low while intensive acaricide use interrupts transmission of pathogens. Evidence is ...
Perry, Brian D.
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Chamboko, Tafireyi
,
Mahan, S.M.
,
Medley, G.F.
,
Minjauw, B.
,
O'Callaghan, C.J.
,
Peter, T.F.
,
[The economics of integrated tick and tick-borne disease control on commercial farms in Zimbabwe]
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The economics of integrated tick and tick-borne disease control on commercial farms in Zimbabwe
Analysis of the transmission dynamics of Cowdria ruminantium, the tick-borne rickettsial agent of heartwater in ruminants, requires accurate measures of infection in vector populations. To obtain these, Amblyomma hebraeum ticks were collected at two heartwater-endemic locations in the lowveld and...
Peter, T.F.
,
Perry, Brian D.
,
O'Callaghan, C.J.
,
Medley, G.F.
,
Mlambo, G.
,
Barbet, A.F.
,
Mahan, S.M.
,
[Prevalence of Cowdria ruminantium infection in Amblyomma
hebraeum ticks from heartwater-endemic areas of Zimbabwe]
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Prevalence of Cowdria ruminantium infection in Amblyomma
hebraeum ticks from heartwater-endemic areas of Zimbabwe
The International Livestock Research Institute (ILRI) conducts research on strategic issues that constrain livestock productivity of resource-poor households, with a focus as smallholder crop-livestock systems. The institute conducts research in the areas of ruminant genetics, ruminant health, fe...
Perry, Brian D.
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Kruska, R.L.
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Medley, G.F.
,
Mukhebi, A.W.
,
O'Callaghan, C.J.
,
Peter, T.F.
,
Reid, Robin S.
,
Williams, T.
,
[Ex ante impact assessment of disease control technologies: The case of vector-borne infections in Africa]
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Ex ante impact assessment of disease control technologies: The case of vector-borne infections in Africa
Heartwater is a severe tick-borne, non-contagious disease of ruminant livestock caused by the rickettsia Cowdria ruminantium, which is endemic in much of sub-Saharan Africa and in the Caribbean. Transmission occurs via ticks of the Amblyomma genus, primarily A. variegatum and A. hebraeum. Intense...
Peter, T.F.
,
O'Callaghan, C.J.
,
Perry, Brian D.
,
Medley, G.F.
,
Mahan, S.
,
[Application of PCR in heartwater epidemiology]
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Application of PCR in heartwater epidemiology
Seventy 1- to 4-year old female indigenous goats were matched and randomised into two groups to measure the effects of naturally acquired trypanosome infections on oestrus and conception. All goats were treated twice with diminazene aceturate (Berenil) at 7 mg/kg body weight at two-week intervals...
Perry, Brian D.
,
Chamboko, Tafireyi
,
Mahan, S.
,
Medley, G.F.
,
Mukhebi, A.W.
,
O'Callaghan, C.J.
,
Peter, T.F.
,
[A study of the effects of trypanosome infection on the fertility of female goats in Lulangwa Valley, eastern Zambia]
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A study of the effects of trypanosome infection on the fertility of female goats in Lulangwa Valley, eastern Zambia
Heartwater, a disease of ruminants caused by the rickettsia Cowdria ruminantium and transmitted by ticks of the genus Amblyomma, is a significant cause of productivity losses in cattle, sheep and goats in most of sub-Saharan Africa. In southern Africa, the vector of C. ruminantium is A. hebraeum....
Perry, Brian D.
,
Chamboko, Tafireyi
,
Mahan, S.
,
Medley, G.F.
,
Mukhebi, A.W.
,
O'Callaghan, C.J.
,
Peter, T.F.
,
[A study of the effects of heartwater and its control on livestock productivity and economics in Zimbabwe]
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A study of the effects of heartwater and its control on livestock productivity and economics in Zimbabwe
O'Callaghan, C.J.
,
McDermott, John J.
,
Katende, J.M.
,
Adams, J.E.
,
Perry, Brian D.
,
Young, A.S.
,
[Analysis of longitudinal serological data for Theileria parva]
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Analysis of longitudinal serological data for Theileria parva
In order to assess the economic impact of heartwater (Cowdria ruminantium infection) and model the impact of improved vaccines against the disease, a field study was conducted to provide data on livestock productivity indicators in Zimbabwe. Cross-sectional studies were performed in the two main ...
Chamboko, Tafireyi
,
Mukhebi, A.W.
,
O'Callaghan, C.J.
,
Peter, T.F.
,
Kruska, R.L.
,
Medley, G.F.
,
Mahan, S.M.
,
Perry, Brian D.
,
[Heartwater and the economics of livestock production on large scale commercial and smallholder farms in Zimbabwe]
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Heartwater and the economics of livestock production on large scale commercial and smallholder farms in Zimbabwe
The tick vectors of heartwater (Cowdria ruminantium infection) in Zimbabwe, Amblyomma hebraeum and Amblyomma variegatum, historically were believed to be confined to the low-lying regions of the south and north-west of the country. However, country-wide surveys performed in 1975-1980 and 1988-199...
Peter, T.F.
,
Perry, Brian D.
,
O'Callaghan, C.J.
,
Medley, G.F.
,
Shumba, W.
,
Madzima, W.
,
Burridge, M.J.
,
Mahan, S.M.
,
[Distributions of the vectors of heartwater, Amblyomma hebraeum and amblyomma variegatum (Acari: Ixodidae), in Zimbabwe]
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Distributions of the vectors of heartwater, Amblyomma hebraeum and amblyomma variegatum (Acari: Ixodidae), in Zimbabwe
Heartwater, caused by the rickettsial organism Cowdria ruminantium and transmitted by ticks of the genus Amblyomma, is considered to be the most important tick-borne disease of cattle in southern Africa, and is second only in importance to East Coast fever (theileriosis) in eastern Africa. This p...
O'Callaghan, C.J.
,
Medley, G.F.
,
Peter, T.F.
,
Perry, Brian D.
,
[Modelling the transmission dynamics of Cowdria ruminantium: Supporting the case for endemic stability]
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Modelling the transmission dynamics of Cowdria ruminantium: Supporting the case for endemic stability