Serological detection and molecular characterization of piroplasmids in equids in Brazil

Abstract

Equine piroplasmosis is a disease caused by the hemoparasites Babesia caballi and Theileria equi and is considered to be the most important parasitic infection affecting Equidae. The objective of the present study was to carry out an epidemiological molecular and serological survey for the presence of these two protozoal organisms in equids from the northwestern region of the State of Rio Grande do Sul (RS), south Brazil. For this purpose, blood samples were collected from 90 equids in the city of Passo Fundo, RS, Brazil. Those were animals used for sport activities, outdoor recreational riding, and work including cattle herding and mounted patrol. Anti-T. equi and anti-B. caballi IgG antibodies were detected in the sera of those animals by commercial ELISA kits. The molecular diagnosis of equine piroplasmosis due to T. equi or B. caballi (or both) consisted in the amplification of the 18S rRNA gene by nested PCR followed by sequencing of the amplified PCR product and sequence comparison and phylogenetic analysis of the isolates; 17 (18.9%) and 5 (5.55%) out of the 90 serum samples tested in this study were positive for T. equi and B. caballi, respectively. Piroplasmid 18S rRNA gene fragments were detected by PCR in 24.4% (22/90) of the samples analysed and shared 99-100% identity with sequences of T. equi by BLASTn. Samples for the phylogenetic analysis were divided into 2 groups. In group A, there was close phylogenetic relationship between 4 sequences and sequences previously reported along the US-Mexico border, in South Africa, and in Brazil. There was a phylogenetic proximity between 5 samples from group B and samples tested by other authors in the US and Spain. Variation of the 18S rRNA gene allowed the identification of 9 new T. equi genotypes in the geographical region studied.

Molecular survey and genetic diversity of piroplasmids in equids from Midwestern Brazil

“…Herein, we confirm that infection is widespread in the studied region, with higher prevalence of T. equi (25.91%) than B. caballi (2.74%) among equids. These findings are similar to those found in other studies conducted in Brazil (HEIM et al, 2007;VIEIRA et al, 2018) and other countries (POSADA-GUZMÁN et al, 2015;GUVEN et al, 2017). This may reflect differences in the biology of the vectors, as well as differences in persistence of the parasite in the equine *Animal age, classified as greater than six months and less than 3 years, greater than 3 years and less than 10 years and greater than ten years.…”

Serological detection and risk factors for equine piroplasmosis in the semiarid region of Pernambuco, Northeastern Brazil

“…The disease is considered endemic in tropical, subtropical and temperate regions (BRÜNING, 1996;KAPPMEYER et al, 2012;AHARONSON-RAZ et al, 2014). It is on the list of notifiable diseases, so infected animals are subject to international travel restrictions (OIE, 2018a), causing problems to the horse industry (VIEIRA et al, 2018). Clinical signs of the disease, which may range from asymptomatic to acute, are characterized by fever, jaundice, intravascular hemolysis based on free hemoglobin in the blood, anemia, hemoglobinuria, edema, bilirubinuria, azotemia, acute renal failure, depression, hepatomegaly, splenomegaly, and lymphadenopathy (DE WAAL, 1992;GUIMARÃES et al, 1998;MEHLHORN & SCHEIN 1998;WISE et al, 2013;ADAM et al, 2017).…”

“…Serological studies on B. caballi and T. equi have been conducted in the south, southeast and central-west regions of Brazil, which have revealed B. caballi prevalence rates varying from 18 to 90% (BARBOSA et al, 1995;HEUCHERT et al, 1999;HEIM et al, 2007;KERBER et al, 2009;VIEIRA et al, 2013;NOGUEIRA et al, 2017;BRAGA et al, 2017) and T. equi prevalence rates from 17 to 100% (TENTER & FRIEDHOFF, 1986;BARBOSA et al, 1995;RIBEIRO et al, 1999;HEUCHERT et al, 1999;XUAN et al, 2001;HEIM et al, 2007;GOLYNSKI et al, 2008;KERBER et al, 1999KERBER et al, , 2009BALDANI et al, 2010;SALVAGNI et al, 2010;VIEIRA et al, 2013;PROCHNO et al, 2014;VIEIRA et al, 2015VIEIRA et al, , 2018FERREIRA et al, 2016;GUIMARÃES et al, 2016;BRAGA et al, 2017;SCHEIN et al, 2018). However, such studies have rarely been carried out in northeastern Brazil.…”

Molecular evidence of Anaplasma phagocytophilum and Theileria equi coinfection in horses from Rio de Janeiro, Brazil

“…Several epidemiological studies have reported the circulation of Theileria equi in Brazil ( Ferreira et al., 2016 , Peckle et al., 2013 , Vieira et al., 2018 ). This pathogen is an intraerythrocytic parasite that infects horses and causes equine piroplasmosis, and it is included on the reportable diseases list B from the World Organization for Animal Health (OIE).…”