Thesis (PhD (Paraclinical Sciences, Veterinary Science))--University of Pretoria, 2009. / Includes bibliographical references. Also available in print format.

Bracken environments harbour the sheep tick (Ixodes ricinus), known vector of a number of diseases. Initial investigation indicated the presence of sheep ticks infected with the Lyme disease spirochaete Borrelia burgdorferi on open moorland areas of the North York Moors and the moorland areas of the South West of the U.K. Some aspects of the problem of Lyme disease on U.K. moorlands were explored in this study. A survey through the summer of 1993 of people using the North York Moors, Dartmoor and the Quantock Hills in Somerset for both work and leisure activities revealed a very high proportion of people (76% of respondents had not heard of Lyme disease) who were unaware of the risk of Lyme disease or of how they might reduce that risk. An examination of three moorland vegetation communities as optimal tick habitats suggested that immature ticks are less dense on heather dominated communities than on either bracken or on Vaccinium dominated communities, and that this may be influenced by the fauna using heather dominated areas. Vaccinium sites showed high densities of all life stages of the sheep tick, as did bracken dominated sites. Ticks were collected throughout the winter months on South Western sites, but not on the North York Moors, emphasising the year round risk from infected ticks in the South West of the U.K. Vegetation management practices as tick control or reduction options in these moorland areas were investigated. Asulam spraying on bracken almost totally removed the above ground frond cover, substantially reduced live buds on the rhizome, but failed to reduce the rhizome dry weight. The density of frond cover was not affected by cutting, height and dry frond weight were reduced, live rhizome buds reduced in number and rhizome dry weight reduced. Short term control of bracken fronds was achieved by both treatments, but neither treatment provided sufficiently conclusive results on which to base long term recommendations. Comprehensive plans for after care on treated sites need to be in place before treatment is carried out. Tick densities were recorded over a two year period on these treated bracken sites. There was a proportional reduction in all tick life stages between 1993 and 1994 on sites sprayed with asulam and on cut sites compared with control sites. Although not statistically significant these results suggested that the methods of bracken control investigated in this study could influence sheep tick densities in the short term.

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Thesis (M.S.)--Georgia Southern University, 2009. / "A thesis submitted to the Graduate Faculty of Georgia Southern University in partial fulfillment of the requirements for the degree Master of Science." Directed by Lorenza Beati. ETD. Includes bibliographical references (p. 42-46) and appendices.

Please read the abstract in the section front of this document / Thesis (PhD (Zoology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted

The control of ticks on cattle has long been a matter of prime importance to stock owners over most of the intensive natural grazing areas in the Southern Hemisphere. The only practical method of dealing with the cattle tick problem in the short term is by treating the infected bovine host with ixodicides i. e. by chemical control. This can be achieved by either plunging the cattle into a dip tank containing aqueous suspensions or emulsions of the ixodicide or by spraying them with dip suspensions in a spray race.

This study was carried out to document the ethno-veterinary plants and non-plant remedies that farmers used to control dermatophilosis and ticks, and validate these in vitro and in vivo, as well as determine how the interface of Amblyomma variegatum and A. hebraeum affected the epidemiology of bovine dermatophilosis at selected small-holder areas in North-West Zimbabwe. A structured questionnaire survey was used to collect information on the control methods used by farmers for the control of bovine dermatophilosis and ticks. A total of 39 plants were used by farmers for various diseases, eleven of these plants were used for the control of dermatophilosis while three were for tick control. Across the study sites, dermatophilosis was controlled using eleven plants. Among these plants; six plants; Cissus quadrangularis, Catunaregan spinosa, Pterocarpus angolensis Carica papaya, Manihot esculenta and Blumea decurrens which were frequently used were selected for further studies. In vitro and in vivo studies were conducted to validate the efficacy of these plants. The minimum inhibitory concentration and bactericidal concentration assays were used for the in vitro validation of C. quadrangularis, C. spinosa and P. angolensis. Dermatophilus congolensis was more sensitive to P. angolensis average MIC = 0.63 mg/ml than to C. quadrangularis average MIC = iii 1.25 mg/ml and C. spinosa average MIC = 2.08 mg/ml. Cissus quadrangularis was selected for in vivo studies as this plant was the one most frequently used by farmers. Its therapeutic efficacy was compared to conventional antibiotics that farmers used to treat dermatophilosis infection. In the in vivo trials C. quadrangularis did not lead to appreciable reduction in clinical disease compared to the conventional drugs. The larval packet assay was the in vitro assay used to validate the efficacy of Carica papaya, Manihot esculenta and Blumea decurrens against larvae of A. hebraeum and Rhipicephalus appendiculatus. Manihot esculenta at 20 % w/v exhibited the highest larvicidal activity against R. appendiculatus. In the in vivo study, efficacy of the plants were investigated on naturally tick-infested cattle. Mannihot esculenta exhibited the largest tick load reduction compared to the other two plants but its performance was lower than that of conventional acaricides. The effect of A. variegatum and A. hebraeum on bovine dermatophilosis was investigated by evaluating how the presence or absence of these ticks and other herd level risk factors predicted clinical dermatophilosis and its prevalence at herd level. A structured questionnaire survey was carried out to collect data on potential risk factors. At the same time, cattle were physically examined for the presence of bovine dermatophilosis, according to a pre-defined case definition, and presence or absence of Amblyomma ticks was also recorded. The multivariable binary logistic model was developed with disease status as outcome, tick presence and infestion and herd level risk factors as predictors. Of the herds examined clinical bovine dermatophilosis was detected in 45% (84/185; 95% CI: 38.2, 52.6%) of them. Herds infested with Amblyomma variegatum were associated with higher odds (OR= 6.8; iv 95% CI: 1.71, 27.10) of clinical dermatophilosis while the association was not significant (P > 0.05) in A. hebraeum infested herds. It was concluded that management practices aimed at movement and tick control would help reduce the prevalence of clinical dermatophilosis in herds.