Acta Tropica 159 (2016) 58–61 Contents lists available at ScienceDirect Acta Tropica jo u r n al homep age: www.elsevier.com/locate/actatropica High prevalence of toxoplasmosis in free-range chicken of the Fernando de Noronha Archipelago, Brazil Fernando Jorge Rodrigues Magalhães a , José Givanildo da Silva b , Müller Ribeiro-Andrade b , José Wilton Pinheiro Júnior b , Rinaldo Aparecido Mota b,* a Veterinary, Health Surveillance Unit of the District of Fernando de Noronha, PE, Brazil b Laboratório de Doenc ¸ as Infecto-Contagiosas dos Animais Domésticos, Departamento de Medicina Veterinária, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil a r t i c l e i n f o Article history: Received 8 December 2015 Received in revised form 24 March 2016 Accepted 27 March 2016 Available online 28 March 2016 Keywords: Free-range chickens Toxoplasmosis Epidemiology a b s t r a c t The present study aimed to determine the prevalence of toxoplasmosis in free-range chickens of the Fernando de Noronha Archipelago, Brazil and to identify risk factors associated with Toxoplasma gondii infection. Blood samples were collected from all the adult chickens raised in the Archipelago and screened by Indirect Fluorescent Antibody Test (430 samples, in total). Univariate analysis (Chi-square) and logistic regression were used to investigate the relationship between various variables possibly predictive of an increased likelihood of T. gondii infection. The overall prevalence of T. gondii infection in chickens of the Fernando de Noronha Archipelago was 88.4% (380/430; 84.6%–91.0%; 95% CI), ranging from 57.1% to 100.0% among the studied properties. The risk factors associated with T. gondii infection were the number of domestic cats in the properties (p = 0.022), the presence of feral cats (p = 0.006) and the presence of an open water source (p = 0.046). Domestic and feral cats should be prevented from accessing the water and food supplied to chickens. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Toxoplasmosis is a worldwide distributed zoonosis caused by the protozoan Toxoplasma gondii that is responsible for significant economic losses to livestock (Dubey, 2010a). Chickens are considered intermediate hosts of T. gondii and a good indicator of environmental contamination because they feed directly on the ground, being continuously exposed to oocyst inges- tion (Dubey, 2010b). Therefore, they are used as sentinel species in areas with high prevalence of human infection (Dubey et al., 2002, 2010). T. gondii infection causes no damage to poultry production and chickens are naturally resistant to clinical toxoplasmosis, rarely developing the disease (Dubey, 2010b). Studies have shown different prevalence of T. gondii infection in poultry raised in extensive systems worldwide (Millar et al., 2012; Chumpolbanchorn et al., 2013; Hamilton et al., 2014) what might be explained by the different places of origin of the animals (Dubey, * Corresponding author at: Departamento de Medicina Veterinária—Universidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros S/N, Dois Irmãos, Recife, PE, CEP 52171-900, Brazil. E-mail address: rinaldo.mota@hotmail.com (R. Aparecido Mota). 2010a). Free-range chickens are an efficient source of infection for cats and other animals, including humans, being the most impor- tant hosts in the epidemiology of toxoplasmosis (Sukthana, 2006; Dubey, 2010b). Given the context, the present study aimed to determine the prevalence of toxoplasmosis in free-range chickens of the Fernando de Noronha Archipelago, Brazil, identify the risk factors possibly associated with T. gondii infection, as well as to define the spatial distribution of the infection. 2. Materials and methods 2.1. Sampling We collected blood samples from 430 adult free-range chickens (males and females) of 25 non-commercial properties regis- tered at the Administration of the State District of Fernando de Noronha (Administrac ¸ ão do Distrito Estadual de Fernando de Noronha—ADEFN), which represent the entire population of adult chickens of the Archipelago. All procedures were approved by the Ethics Committee on Animal Use (CEUA-UFRPE—License no. 116/2015). http://dx.doi.org/10.1016/j.actatropica.2016.03.034 0001-706X/© 2016 Elsevier B.V. All rights reserved.