Co-infections of major tick-borne pathogens of dogs in Andhra Pradesh, South India.

Implementing hemoprotozoan control strategies in dogs has become difficult because of the co-infections. A multiplex polymerase chain reaction (PCR) was carried out for simultaneous detection of the co-infections of , and from dogs (N = 442) in Andhra Pradesh, South India. The co-infection combinations were classified as (i) + + (BEH), (ii) + (BE), (iii) + (BH) and (iv) + (EH) groups. The parasite-specific multiplex PCR amplified 18S rRNA gene of , and . and gene of . . The age, gender, breed, medium, living condition and region of dogs were studied as risk factors for co-infections using logistic regression model. Among the co-infections, the incidence was 1.81%, 9.28%, 0.69% and 0.90% for BEH, BE, BH and EH infections, respectively. Young age (< one year), females, mongrels, rural dogs, kennel dogs and presence of ticks were the identified risk factors for overall prevalence of tick-borne pathogens. The incidence of infection was less in rainy season, especially in dogs with a previous acaricidal treatment. The study concludes that the multiplex PCR assay could simultaneously detect natural co-infections in dogs, emphasizing the need for the assay in epidemiological studies to reveal the real pattern of pathogens and select pathogen-specific treatment protocols.