A review of the epidemiology and control of gastrointestinal nematode infections in cattle in Zimbabwe

In this review, the main gastrointestinal nematodes infecting cattle in Zimbabwe and the epidemiological factors influencing their occurrence are reviewed and discussed. Nineteen gastrointestinal nematode species that belong to seven families have been found to occur in cattle in Zimbabwe. The main genera reported to date are Cooperia, Haemonchus, Trichostrongylus and Oesophagostomumand the dominant species are Cooperia pectinata, Cooperia punctata, Haemonchus placei and Trichostrongylus axei. The mixed infection by several species from the genera is the cause of parasitic gastroenteritis in cattle in Zimbabwe. Production and husbandry practices, season, host age and environment are considered to be the main factors that influence gastrointestinal nematode infection in cattle. The geographical distribution of the gastrointestinal nematodes is also reviewed in relation to the climatic conditions of the country. Various control options are discussed and how they are applicable to the Zimbabwean situation. Based on reports and existing data on the epidemiological features of the gastrointestinal nematode infection in cattle, practical control measures are critically reviewed and recommendations are made for a national control programme

Epidemiological studies of parasitic gastrointestinal nematodes, cestodes and coccidia infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

Between January 1999 and December 2000 faecal samples from 16 264 cattle at 12 dipping sites in the highveld and nine in the lowveld communal grazing areas of Zimbabwe were examined for gastrointestinal (GI) nematode and cestodes eggs, and coccidia oocysts. Strongyle larvae were identified following culture of pooled faecal samples collected at monthly intervals. The effects of region, age, sex and season on the prevalence of GI nematodes, cestodes and coccidia were determined. Faecal egg and oocyst counts showed an overall prevalence of GI nematodes of 43 %, coccidia 19.8 % and cestodes 4.8 %. A significantly higher prevalence of infection with GI nematodes, cestodes and coccidia was recorded in calves (P < 0.01) than in adults. Pregnant and lactating cows had significantly higher prevalences than bulls, oxen and non-lactating (dry cows) (P < 0.01). The general trend of eggs per gram (epg) of faeces and oocysts per gram (opg) of faeces was associated with the rainfall pattern in the two regions, with high epg and opg being recorded during the wet months. The most prevalent genera of GI nematodes were Cooperia, Haemonchus and Trichostrongylus in that order. Strongyloides papillosus was found exclusively in calves. Haemonchus was significantly more prevalent during the wet season than the dry season (P < 0.01). In contrast, Trichostrongylus was present in significantly (P < 0.01) higher numbers during the dry months than the wet months, while Cooperia and Oesophagostomum revealed no significant differences between the wet and dry season. These findings are discussed with reference to their relevance for strategic control of GI parasites in cattle in communal grazing areas of Zimbabwe

Spatial and seasonal patterns of FMD primary outbreaks in cattle in Zimbabwe between 1931 and 2016

Foot and mouth disease (FMD) is an important livestock disease impacting mainly intensive production systems. In southern Africa, the FMD virus is maintained in wildlife and its control is therefore complicated. However, FMD control is an important task to allow countries access to lucrative foreign meat market and veterinary services implement drastic control measures on livestock populations living in the periphery of protected areas, negatively impacting local small-scale livestock producers. This study investigated FMD primary outbreak data in Zimbabwe from 1931 to 2016 to describe the spatio-temporal distribution of FMD outbreaks and their potential drivers. The results suggest that: (i) FMD outbreaks were not randomly distributed in space across Zimbabwe but are clustered in the Southeast Lowveld (SEL); (ii) the proximity of protected areas with African buffalos was potentially responsible for primary FMD outbreaks in cattle; (iii) rainfall per se was not associated with FMD outbreaks, but seasons impacted the temporal occurrence of FMD outbreaks across regions; (iv) the frequency of FMD outbreaks increased during periods of major socio-economic and political crisis. The differences between the spatial clusters and other areas in Zimbabwe presenting similar buffalo/cattle interfaces but with fewer FMD outbreaks can be interpreted in light of the recent better understanding of wildlife/livestock interactions in these areas. The types of wildlife/livestock interfaces are hypothesized to be the key drivers of contacts between wildlife and livestock, triggering a risk of FMD inter-species spillover. The management of wildlife/livestock interfaces is therefore crucial for the control of FMD in southern Africa

Amphistome infections in domestic and wild ruminants in East and Southern Africa: A review

In this article, the main amphistome species infecting domestic and wild ruminants in East and Southern Africa, their snail intermediate hosts and epidemiological features are reviewed and discussed. Twenty-six amphistome species belonging to nine genera from three families occur in domestic and wild ruminants in the region under review and over 70% of them belong to the genera Calicophoron, Carmyerius and Cotylophoron. Of the amphistome species, 76.9% are shared between domestic and wild ruminant hosts – an important observation when considering the different options for control. Seven freshwater snail species belonging to four genera from two families act as intermediate hosts of the identified amphistome species, with the genus Bulinus contributing 57% of the snail species. Some of the snails are intermediate hosts of amphistome species belonging to the same genus or to different genera; a phenomenon not yet fully elucidated as some snails are reported to be naturally infected with amphistome cercariae of unidentified species. Only nine (34.6%, 9/26) of the amphistome species have known snail intermediate hosts, while most (65.4%, 17/26) have unknown hosts. Species of intermediate hosts and the potential of the flukes to infect these hosts, the biological potential of the snail hosts, the definitive hosts management systems and their grazing habits are considered to be the main factors influencing the epidemiology of amphistomosis. Based on the epidemiological features of amphistome infections, various practical control options are discussed. Further research is necessary to determine amphistome–snail associations, develop diagnostic tests that can detect prepatent infections in the definitive host, determine the burden and economic importance of amphistomosis in domestic and wild ruminants and the efficacy of different anthelmintics in the treatment of patent infections

Serological survey of <i>Brucella canis</i> in dogs in urban Harare and selected rural communities in Zimbabwe

A cross-sectional study was conducted in order to detect antibodies for Brucella canis (B. canis) in dogs from urban Harare and five selected rural communities in Zimbabwe. Sera from randomly selected dogs were tested for antibodies to B. canis using an enzyme-linked immunosorbent assay. Overall, 17.6% of sera samples tested (57/324, 95% CI: 13.5–21.7) were positive for B. canis antibodies. For rural dogs, seroprevalence varied from 11.7% – 37.9%. Rural dogs recorded a higher seroprevalence (20.7%, 95% CI: 15.0–26.4) compared with Harare urban dogs (12.7%, 95% CI: 6.9–18.5) but the difference was not significant (p = 0.07). Female dogs from both sectors had a higher seroprevalence compared with males, but the differences were not significant (p > 0.05). Five and two of the positive rural dogs had titres of 1:800 and 1:1600, respectively, whilst none of the positive urban dogs had a titre above 1:400. This study showed that brucellosis was present and could be considered a risk to dogs from the studied areas. Further studies are recommended in order to give insight into the epidemiology of brucellosis in dogs and its possible zoonotic consequences in Zimbabwe. Screening for other Brucella spp. (Brucella abortus, Brucella melitensis and Brucella suis) other than B. canis is also recommended