Genetic diversity of Theileria equi and Babesia caballi infecting horses of Central-Southern Italy and preliminary results of its correlation with clinical and serological status

Manna, Giuseppe; Cersini, Antonella; Nardini, Roberto; Pino, Leticia Elisa Bartolomé Del; Antognetti, Valeria; Zini, Maurizio; Conti, Rena M.; Lorenzetti, Raniero; Veneziano, Vincenzo; Autorino, Gian Luca; Scicluna, Maria Teresa

doi:10.1016/j.ttbdis.2018.05.005

Cited by 31 publications

(37 citation statements)

References 34 publications

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“…Infection of equines with different T. equi clade genotypes has been noted, with studies of naturally infected populations showing differences in the severity of clinical signs between individuals depending on the infecting genotype (Manna et al, ). Additionally, recent experimental work has shown that super‐infection with both T. equi and the newly described T. haneyi is possible, and can be maintained for many months (Sears et al, ).…”

Section: Introductionmentioning

confidence: 99%

Analysis of Theileria equi diversity in The Gambia using a novel genotyping method

Coultous

McDonald

Raftery

et al. 2019

Transbound Emerg Dis

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Theileria equi, one of the primary pathogens causing equine piroplasmosis, has previously been sub‐classified into a number of clades on the basis of 18S SSU rRNA gene sequence diversity. This partitioning of the parasite population has potential implications for host immunity, treatment and vaccine development. To detect and identify different clade genotypes among and within individual equine blood samples, a novel PCR‐based technique was designed and optimized. Theileria equi has only recently been described in The Gambia, and the developed genotyping technique was used to analyse blood samples taken from 42 piroplasmosis‐positive horses and donkeys within the country. Three different T. equi genotypes were detected within the population, including the same genotype as the recently described Theileria haneyi, with 61.9% of individuals found to be infected with more than one genotype. Overall, there was a trend that males were more likely to have a multiple genotype infection. Thus, the novel genotyping technique has been shown to be effective in analysis of field populations and offers researchers a rapid method of identifying multiple T. equi genotypes both within individuals and equine populations in epidemiological studies.

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Section: Introductionmentioning

confidence: 99%

Analysis of Theileria equi diversity in The Gambia using a novel genotyping method

Coultous

McDonald

Raftery

et al. 2019

Transbound Emerg Dis

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“…Most of the focus has been on the immunogenic ema gene family [31]. Ema-1 has been shown to be relatively conserved [32,33], and it is used in the cELISA kit for detection of exposure [34]. However, as in this study, this locus is less sensitive when used in conventional PCR and does not allow discrimination between different strains.…”

Section: Discussionmentioning

confidence: 90%

Genetic Characterization of Piroplasms in Donkeys and Horses from Nigeria

Idoko

Tirosh-Levy

Mazuz³

et al. 2020

Animals

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Equine piroplasmosis (EP) is a tick-borne disease of equids, caused by the two haemoprotozoal parasites: Theileria equi and Babesia caballi. Nigeria constitutes a major crossroads of animal transport in West Africa and may serve as a factor in EP dissemination in the region. The study aim was to characterize EP parasites in donkeys and horses in northern Nigeria using a molecular approach. Blood was collected from 57 donkeys and 47 horses. EP infection was detected and characterized by polymerase chain reaction (PCR). Twenty five donkeys (43.8%) were infected with T. equi, five (8.8%) with B. caballi, three (5.3%) with dual infections. Four horses (8.5%) were infected by T. equi and none by B. caballi. Four of the five known T. equi 18S rRNA genotypes (A, B, C and D) were identified. Theileria equi ema-1 and ema-2 genes were amplified in only 2 and 10 samples, respectively, showing no genetic variation. All B. caballi isolates were classified as rap-1 genotype A1. Twenty-two (42.3%) of the donkeys were positive for anti-T. equi antibodies and 29 (55.8%) were positive for anti-B. caballi antibodies, using immunofluorescence antibody test (IFAT). The study results demonstrate high genetic variation within T. equi parasites, suggesting that donkeys may be reservoirs of EP parasites in West Africa.

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“…Thus, although the number of cases was limited, genotype A may be associated with clinical disease. Genotype A was previously isolated from horses in both endemic and non-endemic countries [5,10,31,35], it was isolated in two outbreaks in the US [36], and was found to be associated with clinical and seropositive cases in Italy [19]. Interestingly, genotype A was the predominant genotype isolated from ticks collected from horses in Israel, including in farms in which this genotype was not isolated from horses (unpublished data).…”

Section: Discussionmentioning

confidence: 92%

“…Interestingly, genotype A was the predominant genotype isolated from ticks collected from horses in Israel, including in farms in which this genotype was not isolated from horses (unpublished data). It is possible that this genotype is more adapted to the tick vector environment and encounter an active barrier at the horse stage, meaning that genotype A is more likely to lead to clinical disease, while genotypes B, C and D are more likely to result in subclinical infection [19]. With the recent concerns regarding the classification of Theileria species according to the 18S rRNA gene [6,7], it is possible that this "A genotype" is the cause of the "classic" equine theileriosis, while other genotypes may represent closely related, less pathogenic, species or subspecies.…”

Section: Discussionmentioning

confidence: 99%

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Parasite load and genotype are associated with clinical outcome of piroplasm infected equines

Tirosh-Levy

Stienman

Levy

et al. 2020

Preprint

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Background: Equine piroplasmosis (EP) is a highly endemic protozoan disease of horses worldwide. While most horses in endemic areas are subclinically infected, the mechanisms leading to clinical outcome are vastly unknown. Moreover, since clinical signs of disease are not specific, and the prevalence in endemic areas is high, it is difficult to determine if EP is the cause of disease. To identify possible mechanisms leading to the clinical outcome in an endemic area, we compared parasite loads and genotypes in clinically and subclinically infected horses.Methods: Blood was collected from horses with clinical signs consistent with EP, and from apparently healthy horses from various locations. Packed cell volume (PCV) and total solids (TS) were measured from each sample. Quantitative and diagnostic PCR were used to quantify and classify EP infection in clinical and subclinical horses.Results: For both parasites, clinical cases were associated with low mean packed cell volume (PCV) and high mean parasite load (P<0.001), enabling to determine a cutoff value between clinically and subclinically infected horses. Theileria equi of subclinical horses classified into three different 18S rRNA genotypes: D (=23), A (n=12) and C (n=5), while all clinical cases classified as genotype A. The sequences of T. equi equi merozoite antigen-1 (ema-1) gene were fairly conserved and all classified as genotype A. The ema-2 sequences were analyzed with all currently published sequences and were mostly classified into one genotype (A) among the three resolved genotypes. Babesia caballi rhoptry associated protein-1 (rap-1) was classified into sub-genotypes A1 (n=14) and A2 (n=5) with no association to clinical outcome. Classification of the 18S rRNA gene (sub-genotypes B1 and B2) was in agreement with the rap-1 classification.Conclusions: The results of this study suggest that quantification of parasite loads of infected horses may be used to distinguish between clinical and subclinical cases. Additionally, we identified T. equi 18S rRNA genotype A to be associated with clinical disease. This finding emphasizes the importance of in-depth genetic characterization of T. equi genotypes to identify possible markers for virulence.

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Genetic diversity of Theileria equi and Babesia caballi infecting horses of Central-Southern Italy and preliminary results of its correlation with clinical and serological status

Cited by 31 publications

References 34 publications

Analysis of Theileria equi diversity in The Gambia using a novel genotyping method

Analysis of Theileria equi diversity in The Gambia using a novel genotyping method

Genetic Characterization of Piroplasms in Donkeys and Horses from Nigeria

Parasite load and genotype are associated with clinical outcome of piroplasm infected equines

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