Michelo Syakalima

Population genetic analysis and sub-structuring in Babesia bovis

The tick-borne protozoan parasite, Babesia bovis is one of the causes of bovine babesiosis, an economically important disease of cattle in tropical and sub-tropical countries. Using the recently published genome sequence of the parasite, we developed a panel of eight mini- and micro-satellite markers and used these to investigate the role of genetic exchange in the population structure and diversity of the parasite using isolates from Zambia and Turkey. This population genetic analysis showed that genetic exchange occurs and that there are high levels of genetic diversity, with geographical sub-structuring quantified using Wrights F Index. Linkage disequilibrium was observed when isolates from both countries were treated as one population, but when isolates from Zambia were analysed separately linkage equilibrium was observed. The Turkish isolates were sub-structured, containing two genetically distinct sub-groups, both of which appeared to be in linkage equilibrium. The results of the Zambian study suggest that a sub-set of the parasite population is responsible for the westward spread of babesiosis into the previously disease-free central region of the country. The Zambian isolates had a significantly higher number of genotypes per sample than those from Turkey and age was found to be a significant predictor of the multiplicity of infection. The high levels of diversity seen in the Zambian and Turkish B. bovis populations have implications in the development of subunit vaccines against the disease and the spread of drug resistance.

The nucleotide sequence of metallothioneins (MT) in liver of the Kafue lechwe (Kobus leche kafuensis) and their potential as biomarkers of heavy metal pollution of the Kafue River.

The study determined heavy metal concentrations and MT1 nucleotide sequence [phylogeny] in liver of the Kafue lechwe. Applicability of MT1 as a biomarker of pollution was assessed. cDNA-encoding sequences for lechwe MT1 were amplified by RT-PCR to characterize the sequence of MT1 which was subjected to BLAST searching at NCBI. Phylogenetic relationships were based on pairwise matrix of sequence divergences calculated by Clustal W. Phylogenetic tree was constructed by NJ method using PHILLIP program. Metals were extracted by acid digestion and concentrations of Cr, Co, Cu, Zn, Cd, Pb, and Ni were determined using an AAS. MT1 mRNA expression levels were measured by quantitative comparative real-time RT-PCR. Lechwe MT1 has a length of 183bp, which encode for MT1 proteins of 61AA, which include 20 cysteines. Nucleotide sequence of lechwe MT1 showed identity with sheep MT (97%) and cattle MT1E (97%). Phylogenetic tree revealed that lechwe MT1 was clustered with sheep MT and cattle MT1E. Cu and Ni concentrations and MT1 mRNA expression levels of lechwe from Blue Lagoon were significantly higher than those from Lochinvar (p<0.05). Concentrations of Cd and Cu, Co and Cu, Co and Pb, Ni and Cu, and Ni and Cr were positively correlated. Spearmans rank correlations also showed positive correlations between Cu and Co concentrations and MT mRNA expression. PCA further suggested that MT mRNA expression was related to Zn and Cd concentrations. Hepatic MT1 mRNA expression in lechwe can be used as biomarker of heavy metal pollution.

Risk analysis of an anthrax outbreak in cattle and humans of Sesheke district of Western Zambia

An anthrax outbreak occurred in November 2010 in five villages of Sesheke district in Western Zambia. Control measures and data collection was carried out immediately the outbreak was reported. The prevalence of the disease in cattle was estimated at 7.4% (45/609) while the average herd size of infected cattle in affected villages was estimated at 121.8 (95% CI 48.8-194.8). Individual mortality per herd varied between 1.70% (3/179) and 20.25% (6/79). The relative risk of infection of cattle in the five affected villages varied between 0.18 (95% CI 0.4-5.7) and 3.7 (95% CI 1.99-6.68). In humans, the disease only affected three people and was characterized by cutaneous carbuncles. The ratio of infected persons per number of infected carcasses varied between 1:37 and 1:49 in affected villages while the overall ratio of people at risk to the number of carcasses was 42:1 indicating that despite availability of a large number of carcasses, human contact with infected carcasses was low. The findings of this study underline the importance of timely disease control measures in reducing the risk of human infections to anthrax in the face of an outbreak.

Bovine Tuberculosis and Brucellosis in Traditionally Managed Livestock in Selected Districts of Southern Province of Zambia

A study was performed in 2008 to estimate the prevalence of tuberculosis and brucellosis in traditionally reared cattle of Southern Province in Zambia in four districts. The single comparative intradermal tuberculin test (SCITT) was used to identify TB reactors, and the Rose Bengal test (RBT), followed by confirmation with competitive enzyme-linked immunosorbent assay (c-ELISA), was used to test for brucellosis. A total of 459 animals were tested for tuberculosis and 395 for brucellosis. The overall prevalence of BTB based on the 4 mm and 3 mm cutoff criteria was 4.8% (95% CI: 2.6–7.0%) and 6.3% (95% CI: 3.8–8.8%), respectively. Change in skin thickness on SCITT was influenced by initial skin-fold thickness at the inoculation site, where animals with thinner skin had a tendency to give a larger tuberculin response. Brucellosis seroprevalence was estimated at 20.7% (95% CI: 17.0–24.4%). Comparison between results from RBT and c-ELISA showed good agreement (84.1%) and revealed subjectivity in RBT test results. Differences in brucellosis and tuberculosis prevalence across districts were attributed to type of husbandry practices and ecological factors. High prevalence of tuberculosis and brucellosis suggests that control programmes are necessary for improved cattle productivity and reduced public health risk.

Cytochrome c Oxidase Sequences of Zambian Wildlife Helps to Identify Species of Origin of Meat

Accurate species identification is a crucial tool in wildlife conservation. Enforcement of antipoaching law is more achievable with robust molecular identification of poached meat. Determining the region where the animal may have been taken from would also be a useful tool in suppression of cross-border trade of poached meat. We present data from a cytochrome c oxidase “barcoding” study of Zambian ruminants that adequately identifies the species of origin of meat samples. Furthermore, the method demonstrates possible improvement and application in regional variation in sequence identity that has a potential for discriminating meat samples from different subpopulations.

Ethnoveterinary treatments for common cattle diseases in four districts of the Southern Province, Zambia

Aim: Ethno veterinary knowledge has rarely been recorded, and no or limited effort has been made to exploit this knowledge despite its widespread use in Zambia. This study documented the types of plants used to treat important animal diseases in rural Zambia as a way of initiating their sustained documentation and scientific validation. Materials and Methods: The study was done in selected districts of the Southern Zambia, Africa. The research was a participatory epidemiological study conducted in two phases. The first phase was a pre-study exploratory rapid rural appraisal conducted to familiarize the researchers with the study areas, and the second phase was a participatory rural appraisal to help gather the data. The frequency index was used to rank the commonly mentioned treatments. Results: A number of diseases and traditional treatments were listed with the help of local veterinarians. Diseases included: Corridor disease (Theileriosis), foot and mouth disease, blackleg, bloody diarrhea, lumpy skin disease, fainting, mange, blindness, coughing, bloat, worms, cobra snakebite, hemorrhagic septicemia, and transmissible venereal tumors. The plant preparations were in most diseases given to the livestock orally (as a drench). Leaves, barks, and roots were generally used depending on the plant type. Conclusion: Ethno veterinary medicine is still widespread among the rural farmers in the province and in Zambia in general. Some medicines are commonly used across diseases probably because they have a wide spectrum of action. These medicines should, therefore, be validated for use in conventional livestock healthcare systems in the country to reduce the cost of treatments.