Cumulative incidence and spatial distribution of dogs exposed to Toxoplasma gondii / Incidência cumulativa e distribuição espacial de cães expostos a Toxoplasma gondii

Abstract Toxoplasma gondii is one of the most important protozoa parasites worldwide. Although many seroprevalence studies have been performed in domestic and wild species, data on the cumulative incidence and the spatial distribution of T. gondii in animals are extremely scarce. In the present study, dogs from Botucatu municipality, São Paulo state, were followed for one year and their blood samples were collected on three moments: days 1, 180, and 360. The sera were submitted to the immunofluorescence antibody test (IFAT) to detect IgG antibodies to T. gondii. Age and sex were compared with IFAT results through statistical tests. Spatial analysis was used to detect clusters of seropositive dogs. Among the 350 dogs that were seronegative on day 1, 53 became seropositive in subsequent samplings; thus, cumulative incidence was 15.1% exposed dogs/year. Age and sex were not associated with serological results. The spatial analysis revealed that seropositive dogs were distributed in all the studied areas, with a significant cluster in a zone with poor sanitary conditions and low socioeconomic status. T. gondii is frequent and widely distributed in the urban area of Botucatu, and impoverished areas are possibly associated with high levels of environmental contamination by this parasite.

Resumo Toxoplasma gondii é um dos parasitas mais importantes mundialmente. Embora muitos estudos de soroprevalência tenham sido realizados em espécies domésticas e selvagens, dados sobre a incidência cumulativa e distribuição espacial de T. gondii em animais são extremamente escassos. No presente estudo, cães do município de Botucatu, estado de São Paulo, foram acompanhados por um ano, e suas amostras de sangue foram colhidas em três momentos: dias 1, 180 e 360. O soro foi submetido ao teste de imunofluorescência indireta (RIFI), para detectar anticorpos IgG para T. gondii. A idade e o sexo foram comparados com os resultados da RIFI por meio de testes estatísticos. Dos 350 cães soronegativos no dia, 1,53 se tornaram soropositivos nas amostragens subsequentes; portanto, a incidência cumulativa foi de 15,1% de cães expostos/ano. A idade e o sexo não tiveram associação com os resultados da sorologia. A análise espacial demonstrou que os cães soropositivos se distribuíram em todas as áreas compreendidas pelo estudo, com uma concentração significativa em uma região com condições sanitárias precárias e baixos níveis socioeconômicos. T. gondii é frequente e amplamente distribuído na área urbana de Botucatu, e regiões empobrecidas podem estar associadas a maiores níveis de contaminação ambiental por esse parasita.

Serosurvey of Borrelia in dogs, horses, and humans exposed to ticks in a rural settlement of southern Brazil / Soroprevalência e fatores associados a Borrelia em cães, equinos e humanos expostos a carrapatos em um assentamento rural do sul do Brasil

Abstract The aims of the present study were to serosurvey dogs, horses, and humans highly exposed to tick bites for anti-Borrelia burgdorferi s.l. antibodies, identify tick species present, and determine risk factors associated with seropositivity in a rural settlement of Paraná State, southern Brazil. Eighty-seven residents were sampled, along with their 83 dogs and 18 horses, and individual questionnaires were administered. Immunofluorescence antibody test (IFAT) was performed on serum samples and positive samples were subjected to western blot (WB) analysis. Anti-B. burgdorferi antibodies were found in 4/87 (4.6%) humans, 26/83 (31.3%) dogs, and 7/18 (38.9%) horses by IFAT, with 4/4 humans also positive by WB. Ticks identified were mostly from dogs and included 45/67 Rhipicephalus sanguineus, 21/67 Amblyomma ovale, and 1/67 A. cajennense sensu lato. All (34/34) horse ticks were identified as A. cajennense s.l.. No significant association was found when age, gender, or presence of ticks was correlated to seropositivity to Borrelia sp. In conclusion, although anti-Borrelia antibodies have been found in dogs, horses and their owners from the rural settlement, the lack of isolation, molecular characterization, absence of competent vectors and the low specificity of the commercial WB kit used herein may have impaired risk factor analysis.

Resumo Os objetivos do presente estudo foram realizar um levantamento sorológico de cães, cavalos e humanos altamente expostos a picadas de carrapatos para anticorpos anti-B. burgdorferi s.l., identificar as espécies de carrapatos presentes, e determinar os fatores de risco associados a soropositividade em um assentamento rural do Estado do Paraná, sul do Brasil. Oitenta e sete residentes foram amostrados junto com seus respectivos 83 cães e 118 cavalos e questionários individuais foram aplicados. O teste de imunofluorescência indireta (IFI) foi realizado nas amostras sorológicas e as positivas foram submetidas a análise por western blot (WB). Anticorpos anti-B. burgdorferi foram detectados em 4/87 (4,6%) humanos, 26/83 (31,3%) cães e 7/18 (38,9%) cavalos pela IFI, com 4/4 humanos também positivos pelo WB. Os carrapatos identificados foram em sua maioria de cães e incluíram 45/67 Rhipicephalus sanguineus, 21/67 Amblyomma ovale e 1/67 A. cajennense sensu lato. Todos (34/34) carrapatos dos cavalos foram identificados como A. cajennense s.l.. Não foram observadas diferenças estatísticas entre idade, sexo ou presença de carrapatos e soropositividade para Borrelia sp. Em conclusão, embora anticorpos anti-Borrelia tenham sido encontrados em cães, equinos e seus proprietários do assentamento rural, a ausência de isolamento, caracterização molecular, ausência de vetores competentes e baixa especificidade do kit comercial de WB utilizado podem ter limitado a análise de fatores de risco.

Leishmania, Babesia and Ehrlichia in urban pet dogs: co-infection or cross-reaction in serological methods?

INTRODUCTION: The present study was designed to assess the occurrence of co-infection or cross-reaction in the serological techniques used for detecting the anti-Leishmania spp., -Babesia canis vogeli and -Ehrlichia canis antibodies in urban dogs from an area endemic to these parasites. METHODS: The serum samples from dogs were tested for the Babesia canis vogeli strain Belo Horizonte antigen and Ehrlichia canis strain São Paulo by immunofluorescence antibody test (IFAT) and by anti-Leishmania immunoglobulin G (IgG) antibody detection to assess Leishmania infection. We used the following four commercial kits for canine visceral leishmaniasis: ELISA, IFAT, Dual Path Platform (DPP) (Bio Manguinhos(r)/FIOCRUZ/MS) and a rK39 RDT (Kalazar Detect Canine Rapid Test; Inbios). RESULTS : Of 96 serum samples submitted to serological assays, 4 (4.2%) were positive for Leishmania as determined by ELISA; 12 (12.5%), by IFAT; 14 (14.6%) by rK39 RDT; and 20 (20.8%), by DPP. Antibodies against Ehrlichia and Babesia were detected in 23/96 (23.9%) and 30/96 (31.2%) samples, respectively. No significant association was identified between the results of tests for detecting Babesia or Ehrlichia and those for detecting Leishmania (p-value>0.05). CONCLUSIONS: In the present study, we demonstrated co-infection with Ehrlichia or Babesia and Leishmania in dogs from Minas Gerais (Brazil); we also found that the serological tests that were used did not cross-react. .