Reactivity against Sarcocystis neurona and Sarcocystis falcatula-like in horses from Southeastern and Midwestern Brazil.
Abstract: Equine protozoal myeloencephalitis (EPM) is a neurological disease caused by Sarcocystis neurona. Immunofluorescence antibody tests (IFATs) have been widely used to identify exposure of horses to S. neurona in Brazil. Here we used IFAT to search for IgG antibodies against Sarcocystis falcatula-like (Dal-CG23) and S. neurona (SN138) in sera from 342 horses sampled in Campo Grande, Mato Grosso do Sul state (Midwestern), and São Paulo, São Paulo state (Southeastern), Brazil. The 1:25 cutoff value was chosen to maximize sensitivity of the test. IgG antibodies against S. neurona were detected in 239 horses (69.88%), whereas IgG antibodies against S. falcatula-like were detected in 177 horses (51.75%). Sera from 132 horses (38.59%) reacted against both isolates. Absence of reactivity was evidenced in 58/342 horses (16.95%). The lower cutoff used, and the presence of opossums infected with S. falcatula-like and Sarcocystis spp. in the regions where the horses were sampled, might justify the high seroprevalence observed here. Owing to the similarity among antigens targeted in immunoassays, reports on S. neurona-seropositive horses in Brazil may also derive from the exposure of horses to other Sarcocystis species. The role of other Sarcocystis species in causing neurological diseases in horses in Brazil remains unclear. Mieloencefalite protozoária equina (MPE) é uma doença neurológica causada por . Reação de imunofluorescência indireta (RIFI) tem sido utilizada para identificar a exposição de equinos à no Brasil. Neste estudo, a RIFI foi utilizada para avaliar a presença de anticorpos IgG anti--like (Dal-CG23) e anti- (SN138) no soro de 342 equinos de Campo Grande, Mato Grosso do Sul (Centro-oeste) e São Paulo, São Paulo (Sudeste), Brasil. O ponto de corte de 1:25 foi escolhido para maximizar a sensibilidade. Anticorpos IgG anti- foram detectados em 239 cavalos (69,88%), enquanto anticorpos IgG anti--like foram detectados em 177 cavalos (51,75%). O soro de 132 animais (38,59%) reagiu contra ambos os isolados. A ausência de reatividade foi evidenciada em 58/342 animais (16,95%). O baixo ponto de corte e a presença de gambás infectados com -like e spp., nas regiões onde os equinos foram amostrados podem justificar a alta soroprevalência aqui observada. Devido à similaridade entre antígenos de superfície detectados nos imunoensaios, relatos de soropositividade contra no Brasil podem resultar da exposição dos equinos a outras espécies de . O papel de outras espécies de como causa de doença neurológica em equinos no Brasil permanece incerto.
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This research article explores the prevalence of IgG antibodies against Sarcocystis neurona and Sarcocystis falcatula-like in horses across southeastern and midwestern Brazil, potentially indicating the presence of a neurological disease, Equine protozoal myeloencephalitis (EPM).
Methodology
The researchers collected sera from 342 horses from two regions of Brazil: Campo Grande, Mato Grosso do Sul state (Midwestern), and São Paulo, São Paulo state (Southeastern).
They used Immunofluorescence antibody tests (IFATs), specifically looking for IgG antibodies against Sarcocystis falcatula-like (Dal-CG23) and S. neurona (SN138).
A 1:25 cutoff value was chosen to maximize test sensitivity.
Results
The prevalence of these antibodies was quite high, with 239 horses (69.88%) having antibodies against S. neurona and 177 horses (51.75%) having antibodies against S. falcatula-like. Antibodies against both isolates were found in sera from 132 horses (38.59%).
58 out of 342 horses (16.95%) showed no reactivity in the tests, indicating they likely hadn’t been exposed to either of these species.
Interpretations and Implications
The researchers suggest that the high prevalence is likely due to both the low cutoff used in the test, increasing sensitivity, and the presence of opossums in the regions sampled, which are known to be infected with Sarcocystis species.
They also discuss the difficulty of accurately identifying exposure to specific Sarcocystis species due to the similarity of antigens targeted in immunoassays, suggesting that reports of S. neurona-seropositive horses in Brazil may also be due to exposure to other species of Sarcocystis.
The role of other Sarcocystis species in causing neurological diseases in horses in Brazil remains unclear, highlighting a potential area for future research. This could have significant implications for the management and treatment of neurological diseases in Brazilian equine populations.
Cite This Article
APA
(2023).
Reactivity against Sarcocystis neurona and Sarcocystis falcatula-like in horses from Southeastern and Midwestern Brazil.
Rev Bras Parasitol Vet, 32(3), e007623.
https://doi.org/10.1590/S1984-29612023031
We confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed. We further confirm that the order of authors listed in the manuscript has been approved by all of us.
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