Ehrlichia canis and Rickettsia conorii Infections in Shelter Dogs: Seropositivity and Implications for Public Health

A cross-sectional study was conducted to gain insight into the epidemiology of canine ehrlichiosis and rickettsiosis in northern Portugal. Specific IgG antibodies to Ehrlichia canis were analysed using a commercial enzyme-linked immunosorbent assay (ELISA), and antibodies to Rickettsia conorii were analysed using a commercial indirect immunofluorescence antibody test (IFAT). A total of 113 dogs from two different shelters were sampled, and seroprevalence values of 0.9% (95% confidence (CI): 0.2-4.8%) for E. canis and 9.7 (95% CI: 5.5-16.6%) for R. conorii were found. Multiple logistic regression investigated risk factors for seropositivity. The odds ratios (ORs) of R. conorii seropositivity were higher for female dogs (OR = 6.429; 95% CI: 1.201-34.407). Dogs seropositive for co-infection (E. canis + R. conorii) were more frequently observed among females (OR = 7.606; CI 95%: 1.478-39.132) and in Shelter 2 (OR = 18.229; 95% CI: 2.190-151.756). These findings show that shelter dogs in northern Portugal are exposed to E. canis and R. conorii, which can affect both canines and humans. It is imperative to adopt a One Health approach to educate the public about the hazards of canine zoonoses and develop legislation and procedures to control their spread and preserve public health.

Seroprevalences of Rickettsia conorii, Ehrlichia canis and Coxiella burnetii in Dogs from Montenegro

PURPOSE

The incidence of vector-borne zoonoses has been increasing in Europe as a result of global climate change, and rickettsioses are a significant etiologic entity among these infections. The objective of this study was to investigate the seroprevalences of Rickettsia conorii, Ehrlichia canis and Coxiella burnetii in dogs in Montenegro.

METHODS

The seroepidemiological study covered 259 dogs, of which 155 were owned dogs suspected of infection with agents of rickettsial aetiology from the continental (Podgorica) or five coastal municipalities of Montenegro (Budva, Herceg Novi, Kotor, Ulcinj and Bar), and 104 dogs were from a public shelter in Podgorica. The presence of specific IgG antibodies against R. conorii was analysed using a commercial indirect enzyme-linked immunosorbent assay (ELISA) test, and the presence of antibodies against E. canis and C. burnetii was analysed using commercial indirect immunofluorescence tests (IFAT).

RESULTS

Seroprevalences of 73.36, 19.3 and 1.16% were determined for R. conorii, E. canis and C. burnetii, respectively. R. conorii was significantly more prevalent (χ² = 14.53; p < 0.001) in owned dogs (81.93%) than in dogs from the public shelter (60.6%), while E. canis was more prevalent (χ² = 12.31; p < 0.001) in dogs from the public shelter (29.81%) than in owned dogs (12.26%). Coinfection with two pathogens was determined in 40 (15.44%) dogs, and the prevalence of R. conorii/E. canis (χ² = 4.23; p < 0.05) was greater in dogs from the public shelter (20.19%) than in owned dogs (10.97%).

CONCLUSION

The prevailing evidence from this study shows that dogs from Montenegro are exposed to pathogens of veterinary and public health importance. This calls for the One Health approach to sensitise the public on the risks of zoonoses from dogs and to formulate policies and strategies to mitigate their spread and safeguard public health.