Seroprevalence and incidence of Toxoplasma gondii and Neospora caninum infection in naturally exposed domestic dogs from a rural area of São Paulo state, Brazil.

Anaiá Da Paixão Sevá,Hilda Fátima Jesus Pena,Silvia Neri Godoy,Fernando Ferreira,Ana Perola Drulla Brandão,Daniela Pontes Chiebao,Tatiana Jimenez-Villegas

doi:10.1590/s1984-29612020053

Abstract

Dogs are hosts of the protozoans Toxoplasma gondii, which causes an important public health disease, and Neospora caninum. Studies that have evaluated toxoplasmosis and neosporosis for prolonged periods in dog populations are rare. We analyzed infection by both parasites in a domestic dog population over three consecutive years in São Paulo state, Brazil. In the 1st, 2nd and 3rd years of collection, 181, 193 and 172 domiciles were visited, and blood samples of 331, 371 and 348 dogs were collected for antibody serology, respectively. The seroprevalence of T. gondii in each year was 27.2%, 22.5% and 43.9%, respectively, and that of N. caninum was 7.8%, 4.8% and 6.8%, respectively. The incidence rates for T. gondii in the 2nd and 3rd collections were 13.2% and 30.0%, and those for N. caninum were 3.3% and 4.4%, respectively. Positive and negative serological conversions for both agents occurred at high frequencies during the study period. This study reveals the canine population's serological profile and demonstrates the constant exposure of dogs to the investigated pathogens, indicating the need for prevention and control measures in the region.

Highlights

Domestic dogs are one of the main reservoirs and hosts of pathogens that infect humans and other domestic and wild animals (Courtenay et al, 2001)
Dogs become infected with N. caninum or T. gondii when they ingest oocysts from feces of definitive hosts, or eat raw or rare meat containing tissue cysts of infected intermediate hosts, such as domestic and wild animals (Dubey, 2003)
N. caninum is the causative agent of neosporosis, which causes neurological clinical signs in this species (McAllister, 1999)

Summary

Introduction

Domestic dogs are one of the main reservoirs and hosts of pathogens that infect humans and other domestic and wild animals (Courtenay et al, 2001). Domestic dogs are intermediate hosts of the Toxoplasma gondii protozoan, and they can be a significant sentinel species for the presence of the agent in the environment and for human infections (Frenkel & Parker, 1996; Salb et al, 2008; Cabezón et al, 2010). Dogs become infected with N. caninum or T. gondii when they ingest oocysts from feces of definitive hosts, or eat raw or rare meat containing tissue cysts of infected intermediate hosts, such as domestic and wild animals (Dubey, 2003). N. caninum is the causative agent of neosporosis, which causes neurological clinical signs in this species (McAllister, 1999) This disease in ruminants is serious, with abortion as its main clinical symptom, suggesting economic importance for the cattle industry (Dubey et al, 2007). Domestic dogs are considered a potential source of agent transmission because they can mechanically transmit the agent by rolling in cat feces containing oocysts or by ingesting feces and excreting oocysts, contaminating the human environment (Lindsay et al, 1997)

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