Sentinel surveillance of selected veterinary and public health pathogens in camel population originating from Southern Punjab province, Pakistan

Abstract

An extended range of host susceptibility including camel has been evidenced for some of the important veterinary and public health pathogens, such as brucellosis, peste des petits ruminants (PPR) and bluetongue (BT). However, in disease endemic settings across many parts of the globe, most of the disease control interventions accounts for small and large ruminants, whereas unusual hosts and/or natural reservoirs, such as camels, remain neglected for disease control measures including routine vaccination. Such a policy drawback not only plays an important role in disease epizootiology particularly in settings where disease is endemic, but also serves an obstacle in disease control and subsequent eradication in future. With this background, using pre-validated ELISA and molecular assays [multiplex PCR, reverse transcriptase (RT)-PCR and real-time (rt)-PCR], we conducted a large-scale pathogen- and antibody-based surveillance for brucellosis, peste des petits ruminants and bluetongue in camel population (n = 992) originating from a wide geographical region in southern part of the Punjab province, Pakistan. Varying in each of the selected districts, the seroprevalence was found to be maximum for bluetongue [n = 697 (70.26%, 95% CI: 67.29-73.07)], followed by PPR [n = 193 (19.46%, 95% CI: 17.07-22.09)] and brucellosis [n = 66 (6.65%, 95% CI: 5.22-8.43)]. Odds of seroprevalence were more significantly associated with pregnancy status (non-pregnant, OR = 2.23, 95% CI: 1.86-5.63, p<0.01), farming system (mixed-animal, OR = 2.59, 95% CI: 1.56-4.29, p<0.01), breed (Desi, OR = 1.97, 95% CI: 1.28-4.03, p<0.01) and farmer education (illiterate, OR = 3.17, 95% CI: 1.45-6.93, p<0.01) for BTV, body condition (normal, OR = 3.54, 95% CI: 1.92-6.54, p<0.01) and breed (Desi, OR = 2.19, 95% CI: 1.09-4.40, p<0.01) for brucellosis, and feeding system for PPR (grazing, OR = 2.75, 95% CI: 1.79-4.22, p<0.01). Among the total herds included (n = 74), genome corresponding to BT virus (BTV) and brucellosis was detected in 14 (18.92%, 95 CI: 11.09-30.04) and 19 herds (25.68%, 95% CI: 16.54-37.38), respectively. None of the herds was detected with genome of PPR virus (PPRV). Among the positive herds, serotype 1, 8 and 11 were detected for BTV while all the herds were exclusively positive to B. abortus. Taken together, the study highlights the role of potential disease reservoirs in the persistence and transmission of selected diseases in their susceptible hosts and, therefore, urges necessary interventions (e.g., inclusion of camels for vaccine etc.) for the control of diseases from their endemic setting worldwide.

Keywords: Bluetongue; Brucellosis; Camel; Endemic; Pakistan; Peste des petits ruminants; Surveillance.