Canine echinococcosis in Kyrgyzstan : detection, diagnosis, and dynamics
mesheuropmc: parasitic diseases
Human echinococcosis is an increasing public health issue in Kyrgyzstan, where Echinococcus granulosus and Echinococcus multilocularis are coendemic and domestic dogs are considered the primary source of human infection. A control scheme based upon dosing dogs with praziquantel was commenced in Kyrgyzstan in 2012 and was evaluated using ELISA tests to measure levels of Echinococcus-specific ‘coproantigens’ in canine faeces. The current study describes methods of interpretation of coproELISA test results, both prior to and during a control scheme, using data collected from dogs in southern Kyrgyzstan over a period of three years.\ud \ud Current methods of coproELISA test interpretation based upon selection of a single cut-off value are described and found to have considerable limitations. To address this, Bayesian mixture modelling was used to transform raw coproantigen data into a metric which approximates the possible worm burden in individual dogs and reduces test misclassification at the population level. This approach was validated using data from a panel of faecal samples of known status and was applied to data from samples of unknown status collected from Kyrgyz dogs. Multiple correspondence analysis was used to characterise the Kyrgyz study sites and identify possible associations with canine infection status (incorporating both coproELISA and coproPCR results), but did not identify any strong relationships. A mixed effects logistic regression modelling approach combined with model averaging was used to identify temporal and seasonal trends in coproantigen and coproPCR prevalence. A trend of decreasing test prevalence over time with pronounced seasonality was found for some test results. Finally, a mathematical model of transmission of both Echinococcus granulosus and Echinococcus multilocularis in Kyrgyzstan was developed and used to simulate the effects of a number of different dog dosing strategies. Canine echinococcosis surveillance and control could be improved by tailoring methods of diagnostic test interpretation (population level/individual level, categorical/continuous) to the situation at hand.