Assessment of Theileria equi and Babesia caballi infections in equine populations in Egypt by molecular, serological and hematological approaches

Abstract

BackgroundEquine piroplasmosis (EP) caused by Theileria equi, Babesia caballi, or both, contributes to significant economic loss in the equine industry and remains uncontrolled in Egypt. This study focuses on surveying T. equi and B. caballi infections and hematological disorders in equine populations in Egypt.MethodsTheileria equi and B. caballi infections were assessed in blood from 88 horses and 51 donkeys in Egypt using light microscopy, indirect immunofluorescent antibody test (IFAT), nested PCR (nPCR), and competitive-ELISA (cELISA) assays. PCR products were examined for specificity by DNA sequencing. Hematological alterations were evaluated using a standard cell counter.ResultsMicroscopic analysis revealed EP infection in 11.4 % and 17.8 % of horses and donkeys respectively. IFAT detected 23.9 % and 17.0 % infection of T. equi and B. caballi, respectively, in horses, and 31.4 % of T. equi and B. caballi in donkeys. T. equi cELISA detected 14.8 % and 23.5 % positive horses and donkeys, respectively, but the B. caballi RAP-1-based cELISA failed to detect any positives, a result hypothesized to be caused by sequence polymorphism found in the rap-1 genes. Nested-PCR analysis identified 36.4 % and 43.1 % positive horses and donkeys, respectively for T. equi and it also identified 19.3 % and 15.7 % positive horses and donkeys, respectively for B. caballi. The overall EP incidence found in the population under study was relatively high and comparable regardless of the diagnostic method used (56.8 % using nPCR and 48.9 % using IFAT). Hematologic analysis revealed macrocytic hypochromic anemia and thrombocytopenia in all piroplasma-infected horses.ConclusionsThe data confirm relatively high levels of EP, likely causing hematological abnormalities in equines in Egypt, and also suggest the need for an improved serological test to diagnose B. caballi infection in this region.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1539-9) contains supplementary material, which is available to authorized users.

Seroprevalence of Theileria equi and Babesia caballi in horses in Spain

“…These authors showed that there was heterogeneity in the 18S rRNA gene both for T. equi and B. caballi in Spain and South Africa. In support of our study and focusing on the RAP-1 gene of B. caballi , Bhoora et al [15], Rapoport et al [79] and Mahmoud et al [62] indicated failure to detect the B. caballi parasite. In accordance with Rapoport et al [79], there could be doubts as to the ability of the cELISA to serve as a sole regulatory test for the international horse trade.…”

“…equi vs. B . caballi)Predominant parasiteReferencesCFTAmericaBrazil58228.5 and 54.6 B. caballi  >  T. equi Kerber et al 2009 [53]EuropeFrance44358 and 12.9 T. equi  >  B. caballi Guidi et al 2015 [38]ELISAAfricaEgypt8814.8 and 0 T. equi  >  B. caballi Mahmoud et al 2016 [62]Sudan15863.5 and 4.4 T. equi  >  B. caballi Salim et al 2008 [85]AmericaBrazil4781 and 90 B. caballi  >  T. equi Xuan et al 2001 [104]Brazil58226.6 and 69.6 B. caballi  >  T. equi Kerber et al 2009 [53]Brazil19878.3 and 69.2 T. equi  >  B. caballi Vieira et al 2013 [100]…”

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).…”

“…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.…”

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

“…A significant degree of agreement between the tests was found in a comparative study by Vieira et al (2015). Other serological studies using these two tests also showed almost perfect agreement between them (GOLYNSKI et al, 2008;SALVAGNI et al, 2010;FARKAS et al, 2013;MAHMOUD et al, 2016). However, IFA tested an increased number of 19 horses with anti-T. equi antibodies titer in comparison with ELISA which tested only 10/19 horses with anti-T. equi antibodies titer (PIKALO et al, 2016).…”