Molecular epidemiology of Theileria equi in horses and their association with possible tick vectors in the state of Rio de Janeiro, Brazil

Abstract

The aim of this study was to detect Theileria equi (Laveran 1901) DNA in horses and ticks using real-time PCR and to list the factors associated with infection in animals located in the Seropedica and Petropolis municipalities of the state of Rio de Janeiro. We tested blood samples from 314 horses and samples from 300 ticks, including 191 Amblyomma cajennense, 104 Dermacentor nitens, and 5 Ixodida larvae. Factors inherent to the horse, the ownership, and animal management were obtained from an epidemiological questionnaire and were evaluated in association with the presence of T. equi DNA in the animals. Among the horses in the study, 81 % (n = 253/314) presented T. equi DNA, and the animals of the Seropedica municipality had the highest infection frequency (91 %, n = 128/141, p < 0.001). The factors that had significantly different infection frequencies by chi-squared or Fisher’s exact tests (p < 0.2) were included in a logistic regression model using the R programming package. Work and walking activity (odds ratio [OR] = 5.7, CI = 2.3–14.4), reproductive activity (OR = 3.8, CI = 1.3–11.5), and tick infestation (OR = 2.6, CI = 1.1–6.2) were factors that favored the presence of T. equi DNA in the animals (p < 0.05). Among the tick samples, A. cajennense and D. nitens were the identified species. The presence of T. equi DNA was observed in 9.9 % (n = 19/191) of the A. cajennense samples and 3.8 % (n = 4/104) of the D. nitens samples. A multivariate analysis revealed that the presence of A. cajennense on the animals (OR = 4.1, CI = 1.8–9.1) was associated with the presence of T. equi DNA in the horses. In the studied municipalities, activities related to work, walking, and reproduction and the presence of ticks on the horses, particularly an intense infestation of A. cajennense, are factors that lead to infection with T. equi in the horses.

Theileria equi and Babesia caballi infection of equids in Punjab, India: a serological and molecular survey

“…Regarding various farm practices under study, due to the breech in management practices in the unorganized farm (Table 3), the incidence of direct contact with tick vectors increases resulting in significant amplification of infection (Kouam et al 2010;Moretti et al 2010;Abutarbush et al 2012;Steinmana et al, 2012;Peckle et al 2013;Sumbria et al 2015). Similar significant result was noted by serological testing also (Table 4).…”

Seroprevalence rates of antibodies against Theileria equi in team roping horses from central-western region of Paraná

“…These results shows that T. equi is widespread in the region studied, suggesting high levels of transmission. Additionally, our data is in accordance with previous studies which have demonstrated that the disease is endemic in Brazil (CUNHA et al, 1996;BALDANI et al, 2004;HEIM et al, 2007;SANTOS et al, 2011;PECKLE et al, 2013). To our knowledge, this is the first report of the detection of IgG antibodies anti-T. equi in Paraná state.…”

“…It should be mentioned that the municipality of Guarapuava, which is located in the high-altitude region of the state of Paraná, has a humid semitropical climate, with an annual average temperature of approximately 16 °C, with winter temperatures that reach bellow 0 °C. Peckle et al (2013) also reported lower infection frequency of T. equi in horses of Petrópolis, a region of Rio de Janeiro state with high altitude, where the annual average temperature is 16 °C and winter temperatures of 0 °C.…”

Molecular and serological detection of Theileria equi, Babesia caballi and Anaplasma phagocytophilum in horses and ticks in Maranhão, Brazil

“…Therefore, sensitive and specific tests for Equine Piroplasmosis diagnosis are required to prevent introduction of causative agents into countries that are regarded free of the infection or disease (Mahmoud et al 2016).The results presented here indicate that PCR is a sensitive assay and proves that the causative agents of Equine Piroplasmosis are circulating in the studied area. Studies performed in Brazil using PCR or IFAT have also detected both agents in horses, as the one reported in Minas Gerais (Heim et al 2007), Rio Grande do Sul (Torres et al 2012), Rio de Janeiro (Peckle et al 2013) and São Paulo (Dória et al 2016). Antibodies against Anaplasma phagocytophilum were detected in low levels however all blood and tick samples were negative by PCR.…”

“…The diagnoses of Equine Piroplasmosis can be done by direct and indirect methods; however, molecular assays appears as useful tools to identify the infection (Figueroa et al 1993, Bashiruddin et al 1999, Nicolaiewsky et al 2001, Peckle et al 2013, Malekifard et al 2014, Dória et al 2016, Mahmoud et al 2016. Therefore, sensitive and specific tests for Equine Piroplasmosis diagnosis are required to prevent introduction of causative agents into countries that are regarded free of the infection or disease (Mahmoud et al 2016).The results presented here indicate that PCR is a sensitive assay and proves that the causative agents of Equine Piroplasmosis are circulating in the studied area.…”