Comparison of GARP and Maxent in modelling the geographic distribution of Bacillus anthracis in Zimbabwe

A number of presence-only models can be used in the prediction of the geographic distribution of diseases and/or their vectors. The predictive performance of these models differs depending on a number of factors but primarily the modeled species’ ecological traits. In this study, the performance of GARP and Maxent, two of the most commonly used modelling methods were compared in predicting presence and absence of anthrax in Zimbabwe using accuracy, sensitivity, specificity, Kappa statistic and the Jaccard coefficient as measures of model performance. The results showed that GARP had higher accuracy than Maxent (GARP = 0.70, Maxent = 0.67). Both methods had equal sensitivity (sensitivity = 0.71), but GARP had higher specificity (GARP=0.70, Maxent=0.67). Both Kappa and the Jaccard coefficient were also higher for GARP (0.335; 0.36) than for Maxent (0.295; 0.34). The results imply that GARP has superior performance over Maxent and is recommended for modelling species habitat suitability.Keywords: ENMs, GARP, Maxent, Anthra

A study on the prevalence of dog erythrocyte antigen 1.1 and detection of canine Babesia by polymerase chain reaction from apparently healthy dogs in a selected rural community in Zimbabwe

A study was carried out to determine the prevalence of blood group antigen dog erythrocyte antigen (DEA) 1.1 in mixed breed dogs in rural Chinamhora, Zimbabwe. DEA 1.1 is clinically the most important canine blood group as it is the most antigenic blood type; hence, DEA 1.1 antibodies are capable of causing acute haemolytic, potentially life-threatening transfusion reactions. In this study, blood samples were collected from 100 dogs in Chinamhora, and blood typing was carried out using standardised DEA 1.1 typing strips with monoclonal anti–DEA 1.1 antibodies (Alvedia® LAB DEA 1.1 test kits). Polymerase chain reaction for detecting Babesia spp. antigen was carried out on 58 of the samples. Of the 100 dogs, 78% were DEA 1.1 positive and 22% were DEA 1.1 negative. A significantly (p = 0.02) higher proportion of females (90.5%) were DEA 1.1 positive than males (69.0%). The probability of sensitisation of recipient dogs following first-time transfusion of untyped or unmatched blood was 17.2%, and an approximately 3% (2.95%) probability of an acute haemolytic reaction following a second incompatible transfusion was found. Babesia spp. antigen was found in 6.9% of the samples. No significant relationship (χ2 = 0.56, p = 0.45) was found between DEA 1.1 positivity and Babesia spp. antigen presence. Despite a low probability of haemolysis after a second incompatibility transfusion, the risk remains present and should not be ignored. Hence, where possible, blood typing for DEA 1.1 is recommended. A survey of DEA 3, 4, 5 and 7 in various breeds is also recommended