ORIGINAL ARTICLE Variables Associated with Infections of Cattle by Brucella abortus., Leptospira spp. and Neospora spp. in Amazon Region in Brazil D. P. Chiebao 1 , S. Y. O. B. Valadas 1 , A. H. H. Minervino 1 , V. Castro 2 , A. H. C. N. Romaldini 2 , A. S. Calhau 3 , R. A. B. De Souza 4 , S. M. Gennari 1 , L. B. Keid 5 and R. M. Soares 1 1 Faculdade de Medicina Veterin aria e Zootecnia, Universidade de S~ ao Paulo, S~ ao Paulo, SP, Brasil 2 Age ˆ ncia Paulista de Tecnologia dos Agroneg ocios, Instituto Biol  ogico, S~ ao Paulo, SP, Brasil 3 Empresa Brasileira de Extens~ ao Rural do Par a, Marituba, PA, Brasil 4 Autonomous Veterinarian Doctor, Santar em, PA, Brasil 5 Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de S~ ao Paulo, Pirassununga, SP, Brasil Keywords: bovine; Neospora spp.; Leptospira spp.; Brucella abortus; Amazon region; Brazil Correspondence: R. M. Soares. Preventive Veterinary Medicine and Animal Health Av. Prof. Dr. Orlando Marques de Paiva, University of Sao Paulo, 87 CEP 05508-270, Butantan, Sao Paulo, SP 05508-270, Brazil. Tel.: +5519 3565 4296; Fax: +5519 3565 4091; E-mail: rosoares@usp.br Received for publication June 29, 2013 doi:10.1111/tbed.12201 Summary The frequency of Neospora spp., Leptospira spp. and Brucella abortus infections in adult cattle was determined in herds of the State of Par a, Brazil, which is an important region for cattle production located in the Amazon region. A total of 3466 adult female cattle from 176 herds were tested, leading to a frequency of seropositive animals of 14.7%, 3.7% and 65.5% and a herd positivity of 87.4%, 41.3% and 98.8% for infections caused by Neospora spp., B. abortus and Leptospira spp., respectively. The five most frequently diagnosed serologic responses to Leptospira spp. were those against serovars hardjo, wolfii, grippo- typhosa, hebdomadis and shermani. The following associations were found: prac- tice of artificial insemination, large farm size, large herd size, large number of dogs and high number of total abortions per year with the presence of antibodies against serovar hardjo; positive results to serovar grippotyphosa with the presence of dogs; inappropriate disposal of aborted foetuses with positivity to serovar heb- domadis. Serovar grippotyphosa was also associated with number of episodes of abortions. Neospora spp. positive herds were associated with episodes of abortion and B. abortus infection with the disposal of dead animals and aborted foetuses on pastures and with the use of artificial insemination. In conclusion, the high frequency of brucellosis, leptospirosis and neosporosis in the region may be a consequence of social, natural and raising conditions as: (i) climate conditions that favour the survival and spread of pathogens in the environment; (ii) farms located in regions bordering forest areas; (iii) farms in areas of difficult access to the veterinary service; (iv) extensive beef herds raised at pastures with different age and productive groups inter-mingled; and (v) minimal concerns regarding hygiene practices and disease prevention measures. Introduction The cattle herd for commercial purposes of Brazil is the second largest in the world. The State of Par a, Northern Brazil, comprises the most important cattle region in the Amazon region accounting with the fifth largest herd in Brazil. The cattle population in this state is 17 403 409 ani- mals registered in 89 985 herds (IBGE, 2008). Leptospirosis is a ubiquitous disease with global distribution that affects humans and a wide variety of domestic animals and wildlife. The disease, which is ende- mic in Americas, is caused by spirochaetes belonging to the © 2013 Blackwell Verlag GmbH • Transboundary and Emerging Diseases. 1 Transboundary and Emerging Diseases