Detection and molecular characterization of Babesia caballi and Theileria equi isolates from endemic areas of Brazil

Abstract

Blood samples were collected from 487 adult horses, including 83 pregnant mares, at a slaughterhouse located in Araguari, Minas Gerais State, Brazil. For each blood sample, the packed cell volume (PCV) was determined, and Giemsa-stained smears were microscopically examined for the presence of hemoparasites. The plasma was examined by the indirect fluorescent antibody test for detection of antibodies against Babesia caballi and Theileria equi. In addition, DNA was extracted and analyzed by a multiplex real-time polymerase chain reaction (PCR), specific for B. caballi and T. equi. Products of PCR were sequenced and compared with each other and with known sequences. The serological results showed a total prevalence of 91.0% for T. equi and 83.0% for B. caballi, while by PCR, prevalences of 59.7% for T. equi and 12.5% for B. caballi were observed. However, no correlations were seen between positivity (neither by serology nor by PCR) and PCV values. As expected, the microscopic examination of blood smears showed low sensitivity in detecting the infections when compared to the PCR. Only 35 out of 570 blood smears were positive, with parasitemias below 0.1%. No congenital transmission was detectable. As far as sequencing is concerned, no differences were seen among the isolates of each species nor among them and known sequences available. These results confirm, by molecular methods, the high prevalence rates of T. equi and B. caballi infections in carrier horses in Brazil. However, no diversity was observed among the isolates within the studied regions.

Prevalence of equine Piroplasmosis and its association with tick infestation in the State of São Paulo, Brazil

“…b Included in the final multivariate model (model significance P < 0.05). RIBEIRO et al, 1999;XUAN et al, 2001;BOTTEON et al, 2002;BALDANI et al 2007;HEIM et al 2007). In addition, it highlights the epidemiological associations between tick infestations and serologically positive results for B. caballi and T. equi in horses.…”

“…al., 1995;HEUCHERT et al, 1999;KERBER et al, 1999, CANOLA et al, 2007HEIM et al 2007;BALDANI et al, 2008). The severity of clinical signs is variable, and in many cases spontaneous recovery may occur without obvious clinical signs.…”

“…Serological studies concerning infection by B. caballi and T. equi have shown that these two agents are widely distributed in Brazil, with herd prevalence ranging from 1.4 to 100% (BARBOSA et al, 1995;BITTENCOURT et al, 1997;KERBER et al, 1999;RIBEIRO et al, 1999;XUAN et al, 2001;BOTTEON et al, 2002;BALDANI et al, 2004;2007;COSTA PEREIRA et al, 2005;HEIM et al, 2007). These values have been shown to be affected by climatic conditions and farm management.…”

Expressão heteróloga da EMA-2 (equi merozoite antigen) de Theileria equi em Pichia pastoris com potencial utilização em imunobiológicos

“…Uma vez no hospedeiro, os esporozoítos infectam os leucócitos (MEHLHORN & SCHEIN, 1998) e posteriormente os eritrócitos (UILENBERG, 2006). A transmissão congênita de T. equi também pode ocorrer levando ao aborto ou morte peri natal (HEIM et al, 2007). Os sinais clínicos variam de quadros assintomáticos a agudos (febre, icterícia e anemia).…”

“…Os sinais clínicos variam de quadros assintomáticos a agudos (febre, icterícia e anemia). Animais que se recuperam de infecções agudas deixam de apresentar os sintomas e permanecem como reservatórios de T. equi, mantendo a doença endêmica (HEIM et al, 2007). Devido à grande disseminação de ambos, T. equi e os diversos carrapatos vetores, o diagnóstico e prevenção desta enfermidade se fazem necessários tanto em áreas endêmicas como em não endêmicas (HUANG et al, 2003).…”