Prevalence of leptospirosis in donkey and associated risk factors

Abstract

Leptospirosis is a neglected zoonosis of global importance with a complex epidemiology that affects humans, domestic and wild mammals. Several studies have addressed Leptospira sero-prevalence and risk factors in horses worldwide, including South Africa. Nevertheless, sero-prevalence of Leptospira spp. in donkeys around Ngaka Modiri Molema district (NMMD), North West Province is unknown. The main purpose of the present study was to estimate the sero-prevalence of eight Leptospira serovars and identify factors associated with the infection in the NMMD of the North West Province, South Africa. The study was carried out between March 2017 and October 2018 across NMMD. A cross-sectional study was adopted for this study. A total of 365 blood samples were collected from healthy donkeys and sera were tested with live antigen suspensions of leptospiral serovars including serovars Canicola, Bratislava Hardjo, Grippotyphosa, Icterohaemorrahagiae Szwajizak, Tarassovi and Pomona using the microscopic agglutination test (MAT). Furthermore, a questionnaire was used to collect data on the risk factors for Leptospira sero-status. Factors associated with the presence of Leptospira antibodies were assessed using univariate and multivariate logistic regression analysis, Odds ratio and their 95% confidence interval were computed. Of the 365 donkeys tested for the presence of Leptospira antibodies, the majority (29.6%; n=108/365) were from Mafikeng local municipality and the rest (19.7%; n=72/365) were from Ratlou. The lowest proportion (8.2 %; n=30/365) of donkeys was from Ditsobotla. Just over half, (58.1%; n=212/365) of donkeys tested were female and the remaining 41.9% were male. In addition, most donkeys (41.9%; n=153/365) were between 6-12 years old, followed by those between 0-5 years (37%; n=135/365), and only 20.3% (n=74/365) were above 12 years. Antibodies against Leptospira were found in 11.5% (95% CI: 4.86-18.14) healthy looking donkeys. The most common leptospiral serovar against which serum antibodies were detected was serovar Bratislava (81%; n=34/42) followed by Serovars Tarassovi (19.04%; n=8/42). Based on the final logistic regression model, presence of horses and agricultural activities in the vicinity of donkey housing properties were negatively significantly associated with the presence of antibodies against Leptospira sero-positivity. Furthermore, males were over four times more likely to test positive than were females (OR = 4.88; p ≤ 0.0001; 95% CI [2.01-11.82]), there was a statistical significant difference between males and females. Although, donkeys within the vicinity of fruits and vegetables farming (OR = 0.093; p ≤ 0.0001; 95% CI [0.031-0.27]) and those with horses in the vicinity (OR = 0.226; p ≤ 0.002; 95% CI [0.089-0.57]) had a lower odd of testing positive, the differences were negatively significant. The present study concluded that the sero-prevalence of Leptospira in donkeys was relatively low 11.5% (95% CI: 4.86-18.14) in the NMMD and that Leptospira interrogans serovars Bratislava and Tarassovi were the most commons serovars and hence, donkeys may serve as reservoir for Leptospira bacteria. Furthermore, this study found that donkeys in the study area are reservoirs for the predominant serovar Bratislava and the less dominant serovar Tarassovi. Gender of the donkey is a risk factor for Leptospira seroprevalence. Further studies are needed to investigate the role of agricultural activities in the vicinity of the dwellings of donkeys in the occurrence of Leptospira in the study area.