Toxoplasma gondii, Neospora caninum and Leishmania amazonensis antibodies in domestic dogs in the western Brazilian Amazon region / Toxoplasma gondii, Neospora caninum e Leishmania amazonensis em cães domésticos da Amazônia Ocidental Brasileira

Amostras de sangue de 99 cães domiciliados foram coletadas no meio urbano (n = 33) e rural (n = 66) do município de Lábrea, estado do Amazonas, Brasil. Dentre as amostras rurais, 40 foram obtidas em comunidades ribeirinhas e 26 em comunidades indígenas, ambas ao longo do rio Purus. Durante a amostragem foi aplicado um questionário com informações sobre sexo, idade, viver em áreas secas ou alagadiças, acesso ou não às ruas (cães urbanos) e acesso à floresta. A presença de anticorpos contra Toxoplasma gondii, Neospora caninum, Leishmania infantum chagasi e Leishmania amazonensis foi detectada pela reação de imunofluorescência indireta (RIFI) com ponto de corte de, respectivamente, 16, 50, 40 e 40. Associação entre as variáveis qualitativas e a positividade para cada um dos parasitos foi avaliada pelo teste do χ2 (p < 0,05). A ocorrência de animais com anticorpos contra T. gondii, N. caninum e L. amazonensis foi de, respectivamente, 61,6%; 7,1% e 8,1%. Nenhuma amostra foi positiva para L. infantum chagasi. A variável viver em área urbana (p=0,041) apresentou associação com ocorrência de T. gondii e o número de cães positivos a T. gondii aumentou com a idade (p = 0,0006). A variável sexo (machos) apresentou associação com N. caninum (p = 0,018) e nenhuma variável apresentou associação com L. amazonensis. Os títulos de anticorpos contra T. gondii variaram de 64 a 32.768; contra N. caninum de 100 a 800 e contra L. amazonensis de 40 a 640. T. gondii e L. amazonensis são dois agentes de importantes zoonoses e encontram-se ativos na região. O município estudado, especialmente as comunidades ribeirinhas, possuem peculiaridades geográficas, sociais e ecológicas distintas e necessitam maior atenção das autoridades para o controle desses agentes.(AU)

Blood samples from 99 domestic dogs were collected in the urban area (n = 33) and rural area (n = 66) of the municipality of Lábrea, state of Amazonas, Brazil. Among the rural samples, 40 were collected in riverine communities and 26 were collected in Indian communities, both along the Purus River. During the sampling, a questionnaire was applied to obtain information relating to sex, age, living in dryland or seasonally flooded areas, access to the streets (for urban dogs) and access to forests. The presence of antibodies against Toxoplasma gondii, Neospora caninum, Leishmania infantum chagasi and Leishmania amazonensis was detected by means of the indirect fluorescent antibody test (IFAT) with cutoffs of 16, 50, 40 and 40, respectively. The association of each qualitative variable, with each parasite and positivity for each of them, were evaluated using the χ2 test (p < 0.05). T. gondii, N. caninum and L. amazonensis antibodies were found, respectively, in 61.6%, 7.1% and 8.1% of the animals examined. None of the samples were positive for L. infantum chagasi. The variable of living in an urban area (p = 0.041) presented an association with occurrence of T. gondii and the positivity for T. gondii increased with age of the dogs (p = 0.0006). The variable of male sex presented an association with N. caninum (p = 0.018) and no variable presented any association with L. amazonensis. The antibody titers against T. gondii ranged from 64 to 32,768; against N. caninum from 100 to 800; and against L. amazonensis from 40 to 640. Both T. gondii and L. amazonensis are important zoonotic agents and are active in this region. The municipality studied, and especially its riverine communities, has geographic, social and ecological peculiarities. This region requires greater attention from the authorities for controlling these agents.(AU)

Epidemiological aspects of Toxoplasma gondii infection in riverside communities in the Southern Brazilian Amazon

INTRODUCTION: Toxoplasma gondii infection is widely prevalent in humans and other animals worldwide. Information on the prevalence of T. gondii infection is scarce in some regions of Brazil, including riverside communities along the Amazon River basin. M METHODS: The prevalence of T. gondii in 231 people, aged 1-85 years, who were living in four riverside communities along the Purus River, Lábrea, State of Amazonas, Brazil, was determined. Antibodies against T. gondii were assayed using a commercial enzyme-linked immunosorbent assay (ELISA) kit. The hearts and brains of 50 chickens, which were raised free-range in the communities, were pooled according to the community of origin and bioassayed in mice. The isolates were genotyped using polymorphisms at 12 nuclear markers (SAG1, 5' and 3'-SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, Apico and CS3). RESULTS: The overall seroprevalence of T. gondii was 56.7% (131/231). IgG antibodies were presented by 117 (89.3%) and IgM by 14 (10.7%) of the 131 positive individuals. No association between age group and gender with prevalence was observed (chi-square test, p > 0.05); however, the comparison between localities showed that the seroprevalence of T. gondii was significantly lower among the individuals living in the Boca do Ituxi (p < 0.05) community. Five isolates of T. gondii were obtained in the mouse bioassay, and genotyping revealed two complete genotypes that had not been described previously and three mixed isolates. CONCLUSIONS: These results support previous findings that T. gondii population genetics are highly diverse in Brazil and that T. gondii infection is active in these riverside communities. .