Seroprevalence and risk factors associated with Neospora caninum infection in different dog populations in Spain

In this study, Neospora caninum seroprevalence and some associated risk factors were investigated in four different dog populations in Spain. N. caninum seropositivity was significantly higher in farm dogs (51%, 51/100) (P < 0.001) and lower in household dogs (2.9%, 3/102) (P < 0.0001). The seroprevalence in hunting (23%, 23/100) and stray (24.5%, 23/94) dogs was moderate, and no significant differences were observed between these two populations (P > 0.05). A significantly higher number of dogs showed titres of 1:50–1:100 (68%, 68/100) than ≥1:200 (33%, 33/100) titres (P < 0.0001). N. caninum antibodies were more often detected in mixed breed than pure breed dogs (P < 0.01), but when data were stratified by dog type a significant association was not found (P > 0.05). A significantly higher prevalence of N. caninum was observed in dogs over 1 year old (P < 0.01), indicating that horizontal transmission may be the most important route of infection. The presence of N. caninum antibodies was significantly more frequent in Leishmania infantum-seropositive hunting (P < 0.05) and stray dogs (P < 0.00001). This study confirms that farm, stray and hunting dogs can be considered at-risk dog populations for N. caninum infection in Spain.