Abstract
A pilot animal disease surveillance program was implemented at four abattoirs in Phnom Penh, Cambodia between October 2019 to January 2020. A total of 1,141 samples were collected from 477 cattle and 664 swine. Serological testing was performed using commercial antibody ELISA kits for zoonotic and high impact animal diseases, namely brucellosis, Q fever, CSF, PRRS and ASF. Only two samples tested positive for brucella antibodies (0.2% (0.4, 0.6), n = 1,141). The seroprevalences of Q fever was 0.8% (0.3, 2.1, n = 477) in the cattle samples while CSF, PRRS and ASF in pigs were 55.4% (51.6, 59.2, n = 655), 81.2% (78.1, 84.0, n = 655) and 2.6% (1.6, 4.1, n = 664), respectively. All 38 doubtful and 17 positive ASF antibody ELISA samples were negative when tested by real-time PCR. Statistical analyses demonstrated that the factors that were significantly associated with positive results of Q fever was sampling date (p-value = 0.04), and for ASF was the location of the abattoir (p-value = 0.002). Significant risk factors for both CSF and PRRS were the province of origin of the animals (CSF: p-value = 0.002; PRRS: p-value = 0.004) and sample collection month (CSF: p-value = 1.6 x 10− 6 ; PRRS: p-value = 4.8 x 10− 13). In conclusion, the prevalence of zoonotic diseases tested for in this study were very low. The high prevalences of CSF and PRRS antibodies were most likely the result of vaccination. All ASF seropositive pigs, including those that gave equivocal results, originated from large-scale Cambodian-based commercial farms, as well as Thailand, which raises questions about possible illegal vaccination or low-pathogenicity ASF variants. The pilot abattoir serosurveillance program described here has the potential to provide a sentinel for incursions of novel and endemic pathogens although further work is required to demonstrate its capacity to provide information on the longitudinal disease trends.