Anthrax is an important disease caused by the bacterium Bacillus anthracis affecting both domestic and wild animals at the wildlife/livestock interface, defined here as a physical space in which wild and domestic species overlap in range and potentially interact. In endemic regions, sporadic anthrax outbreaks occur, causing significant deaths of both wildlife and livestock and sporadically, humans. However, it may also occur as isolated outbreaks with a few animals affected. Such isolated anthrax outbreaks maybe missed. High seroprevalence among carnivores suggests either regular non-fatal exposure to the pathogen circulating in a given environment, or contact with missed cases through consumption of anthrax carcases. To investigate the relevance of this potential indicator, a cross-sectional study was conducted to determine anthrax seroprevalence in domestic dogs (Canis lupus familiaris) from selected interface and non-interface areas of Zimbabwe with known history of anthrax outbreaks. Based on past anthrax outbreaks in the respective areas, the sites were further classified as high or low risk areas for anthrax outbreaks. Sera were collected from domestic dogs (n = 186) and tested for antibodies against B. anthracis protective antigens (PA) using an ELISA test. The overall seroprevalence was 51.6% (96/186; 95% CI 44.2-59.0). Sites from the non-interface areas recorded a significantly (P < 0.001) higher (72.1%) anthrax seroprevalence compared with those from the wildlife -livestock interface (41.5%). The results demonstrated a strong association (χ2 = 14.3; OR = 3.2, 1.6 < OR < 6.2, P < 0.001) between anthrax seropositivity and interface type. Low-risk sites (42.5%) had a significantly (P = 0.044) lower seroprevalence compared with high-risk sites (58.5%) but still demonstrated high seroprevalence for areas where anthrax was last reported more than 20 years back. Dogs from Tsholotsho South were more than 90-times (OR = 96.5, 13.5 < OR < 690.8) more likely to be seropositive compared with those from Hwange. The study demonstrated the potential to use domestic dogs as indicators of anthrax in the study areas to survey anthrax circulation in supposed low-risk areas and calls for a redefinition of both low and high risk areas for anthrax in Zimbabwe based on an improved surveillance.
A structured questionnaire survey was conducted to determine the ethno-veterinary practices and other control methods used by smallholder farmers for the management of bovine dermatophilosis and ticks. A total of 153 farmers were interviewed from Njelele, Zhombe communal and Shamrock resettlement areas. Crop production contributed most to livelihoods (83.2 %) while livestock contributed 9.0 %. Over 90 % of the respondents had attended school up to primary level, with 11.4 % undergoing animal health and husbandry training. Treatment of livestock diseases was practised by 96 % of the farmers, and 49.7 % of these farmers used ethno-veterinary medicines. Across the study sites, dermatophilosis was controlled using the following plants: Cissus quadrangularis (59.7 %), Catunaregam spinosa (10.5 %), Pterocarpus angolensis (10.5 %), Kalanchoe lanceolata (5.3 %), Aloe chabaudii (3.5 %), Cassia abbreviata (1.8 %), Dichrostachys cinerea (1.8 %), Urginea sanguinea (1.8 %), Ximenia caffra (1.8 %) and a plant locally called umfanawembila (1.8 %). Carica papaya and two plants, locally called mugimbura and umdungudungu, were used for tick control, and these were reported once from Njelele communal. Other control methods, besides plants or conventional drugs, were used by 28 % of the farmers for the treatment of dermatophilosis and ticks. Some farmers (14.4 %) claimed that ethno-veterinary medicines performed better than conventional drugs. The study revealed that farmers used ethno-veterinary medical practices for the treatment of dermatophilosis but rarely for tick control.
<span style="font-family: arial,helvetica;">A cross-sectional survey was conducted to determine tick infestation, and udder and teat damage in 286 lactating cows and heifers at six properties in the smallholder and commercial sectors in Gwanda district of Matabeleland South Province, Zimbabwe. Eight tick species were identified: <em>Amblyomma hebraeum, Hyalomma truncatum, Hyalomma marginatum rufipes, Rhipicephalus evertsi evertsi, Rhipicephalus (Boophilus) decoloratus, Rhipicephalus appendiculatus, Rhipicephalus zambeziensis and Rhipicephalus simus</em>. Overall, 81.5 % of the cattle were tick infested; prevalence of tick-infested cattle was significantly higher on communal land (93.8 %) and recently claimed land (85.1 %) than on commercial farms. The mean tick load on infested cattle on communal land was significantly higher than in the other two sectors. Although 53 % of the sampled cattle had some degree of udder and teat damage, very few farmers (2.6 %) treated their cattle for these conditions. Udder damage was ca. two times and three times, respectively, more likely to occur in cattle on communal land compared to cattle on recently claimed land and commercial farms. The occurrence of <em>R. appendiculatus and R. zambeziensis</em> indicate that the cattle population in the study area is at high risk of a theileriosis outbreak, a tick-borne disease that has not been reported from this area.</span>
Anthrax is an important but neglected zoonosis in southern Africa and elsewhere which occurs naturally in herbivorous wildlife and livestock. Fatal outbreaks in animals are spaced by potentially extended periods of non-activity during which the bacterium is maintained in soil. The ecology of the pathogen in the multi-host system and the environment is still not fully understood. This study investigated the patterns of anthrax in Zimbabwe in order to better understand the occurrence of disease in susceptible wildlife and livestock and hence its control. The study used available data in governmental reports between 1995 and 2018 and structured interviewer-administered questionnaires of local communities in three porous wildlife-livestock-human interface sites where livestock/wildlife interactions were documented from previous researches. Two non-interface sites were also included for comparison based on known previous anthrax outbreaks. Respondents from non-interface sites had significantly higher odds (χ
2
= 23.2, OR = 3.5, 2.1
Background: Bovine dermatophilosis, an important skin disease of cattle caused by Dermatophilus congolensis, negatively impacts the livelihoods of small-holder farmers in Zimbabwe. This impact is through, morbidity, loss of draught animal power, costs incurred to manage the disease, losses associated with devalued damaged hides and the resultant culling of some of the affected cattle. Due to the inaccessibility of conventional drugs to manage bovine dermatophilosis, farmers have been reported to use local medicinal plants to manage the disease. The aim of the study was to evaluate the in vitro antimicrobial activities of three plants that small-holder farmers in Zimbabwe used to manage bovine dermatophilosis. Methods: Dried plant materials were ground into powder and extracted individually using, water, 80 % acetone and 80 % methanol. The antimicrobial properties of the plants were evaluated against two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and one Gram-positive (Staphylococcus aureus) reference bacterial strains. They were further evaluated against a field isolate of Dermatophilus congolensis. The assays used were the disc diffusion, minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). Results: Acetone and methanol extracts had superior inhibitory activities than did those of water. Pterocarpus angolensis DC extracts had better inhibitory properties with absolute MIC values of 0.156 -5 mg/ml, Cissus Quadrangularis L had MIC values in the range 0.156 -5 mg/ml while that of Catunaregam spinosa Thunb, Terveng was 0.156 -10 mg/ml. Dermatophilus congolensis was more sensitive to Pterocarpus angolensis DC average MIC = 0.63 mg/ml than to Cissus quadrangularis L average MIC = 1.25 mg/ml and Catunaregam. spinosa Thunb, Terveng average MIC = 2.08 mg/ml. Conclusion: These results suggest the potential antibacterial activities of extracts of the three plants and hence farmers are, in a way, justified in using the plants. Better results (lower MIC) could be obtained by extracting and evaluating pure active compounds of the plants.
A cross-sectional study was conducted to assess cattle owners' awareness, perceptions, attitudes and drug-usage practices with regard to bovine dermatophilosis. Knowledge of these farmers' attributes is important for animal health policy makers in their endeavours to provide optimum disease control strategies that are acceptable to the communities. Data on cattle owner awareness of bovine dermatophilosis, causes, treatment practices, perceptions about its importance and potential dangers to humans were collected using an interviewer-administered questionnaire. A total of 185 stockowners and cattle herds were involved in the study, with bovine dermatophilosis determined clinically by veterinarians. The results showed that 45.4% of the herds were clinically positive for dermatophilosis, and most farmers (79.5%) were generally aware that dermatophilosis was a cattle disease. In the event of a dermatophilosis outbreak in a herd, 74.1% of the farmers treated their cattle using antibiotics; the proportion of farmers treating cattle did not differ (p > 0.05) across the diptanks. Fifty-two farmers (52/63) indicated that drugs had to be administered four to seven times before an animal recovered from infection. Tetracyclines were the antibiotics used by most farmers (79.3%) to treat dermatophilosis, with 19.1% using penicillins. Concerns were raised by farmers about the effectiveness of these drugs against bovine dermatophilosis. Across the study sites, 48.6% and 27.6% of the farmers perceived bovine dermatophilosis to be an important disease at the herd and area level, respectively. A small proportion (12.4%) of the farmers regarded bovine dermatophilosis as a potentially zoonotic disease. The high level of stockowners' general awareness, with regards to bovine dermatophilosis, sets ideal conditions for the mobilisation of farmers by animal health authorities in the control of the disease. However, further research needs to be undertaken to investigate effective antibiotic delivery protocols and the potential zoonotic impact of bovine dermatophilosis in a situation of high disease prevalence.
A cross-sectional study was conducted to investigate factors for clinical dermatophilosis herd-level positivity in smallholder dip tanks from Gokwe (Chemawororo, Gwanyika), Kwekwe (Koronika) and Chegutu (Chivero), Zimbabwe, between September 2013 and April 2014. A total of 185 herds were clinically examined for disease and tick infestation. Data on herd and potential herd level risk factors were collected using a structured questionnaire. A herd was classified as clinically positive if an animal satisfied any of the following criteria: small lesions characterised by hairs clumping like a small paint brush, clear exudative circumscribed lesions with scabs of at least 1 cm in diameter and confluent progressive exudative scab lesions affecting significant parts of the animal's body. Amblyomma variegatum and Amblyomma hebraeum ticks were identified in situ with further laboratory confirmation. The potential herd-level risk factors for clinical dermatophilosis were tested using multiple logistic regression with herd infection status (positive, negative) being the binomial outcome and risk factors being predictors. Of the herds examined, clinical bovine dermatophilosis was detected in 45 % (84/185, 95 % confidence interval (CI) 38.2, 52.6 %) of the herds. The herd prevalence ranged from 6.9 % (95 % CI 0.00, 16.7) to 56.7 % (95 % CI 43.8, 69.6) with Chivero and Chemawororo dip tanks recording the lowest and highest prevalence, respectively. Herds infested with A. variegatum were associated with higher odds (OR = 6.8, 95 % CI 1.71, 27.10) of clinical dermatophilosis while the association was not significant (p > 0.05) in A. hebraeum-infested herds. A history of having bought cattle (OR = 3.5, 95 % CI 1.09, 11.12) compared to not buying was associated with increased herd clinical positivity status. It was concluded that management practices aimed at movement and tick control would help reduce the prevalence of clinical dermatophilosis in cattle herds.
Background Ticks transmit several diseases that result in high morbidity and mortality in livestock. Tick-borne diseases are an economic burden that negatively affect livestock production, cost countries billions of dollars through vaccine procurement and other disease management efforts. Thus, understanding the spatial distribution of tick hotspots is critical for identifying potential areas of high tick-borne disease transmission and setting up priority areas for targeted tick disease management. In this study, optimised hotspot analysis was applied to detect hotspots and coldspots of 14 common tick species in Zimbabwe. Data on the spatial distribution of tick species were obtained from the Epidemiology Unit of the Division of Veterinary Field Services of Zimbabwe. Results A total of 55,133 ticks were collected with Rhipicephalus decoloratus being the most common species (28.7%), followed by Amblyomma hebraeum (20.6%), and Rhipicephalus sanguineus sensu lato (0.06%) being the least common species. Results also showed that tick hotspots are species-specific with particular tick species occupying defined localities in the country. For instance, Amblyomma variegatum, Rhipicephalus appendiculatus, Rhipicephalus decoloratus, Rhipicephalus compostus, Rhipicephalus microplus, Rhipicephalus pravus, and Rhipicephalus simus were concentrated in the north and north eastern districts of the country. In contrast, Amblyomma hebraeum, Hyalomma rufipes, Hyalomma trancatum and Rhipicephalus evertsi evertsi were prevalent in the southern districts of Zimbabwe. Conclusion The occurrence of broadly similar hotspots of several tick species in different districts suggests presence of spatial overlaps in the niche of the tick species. As ticks are vectors of several tick-borne diseases, there is high likelihood of multiple disease transmission in the same geographic region. This study is the first in Zimbabwe to demonstrate unique spatial patterns in the distribution of several tick species across the country. The results of this study provide an important opportunity for the development of spatially-targeted tick-borne disease management strategies.
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