Sindbis virus neutralising antibodies detected in Swedish horses

Agnes Björnström,Anne-Lie Blomström,Manish Chandra Singh,Jenny C Hesson

doi:10.1016/j.onehlt.2021.100242

Agnes Björnström, Anne-Lie Blomström + Show 2 more

Open Access

https://doi.org/10.1016/j.onehlt.2021.100242

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Abstract

A number of viruses transmitted by mosquitoes are well known to cause disease in both humans and horses, ranging from mild fevers to mortal neurological disease. A recently discovered connection between the alphavirus Sindbis virus (SINV) and neurological disease in horses in South Africa initiated this serological study in northern Europe, where the same genotype of SINV (SINV-I) is also highly endemic. We tested 171 serum samples, originally obtained from horses for other reasons from April to October 2019, for presence of SINV neutralising antibodies using a plaque reduction neutralisation test (PRNT). The serum from six horses reduced the plaque count more than 80%, and two out of these reduced the plaque count more than 90%. These horses were sampled in six different regions of Sweden, and included individuals sampled from April to August. This study shows that horses in Sweden have become infected with SINV and developed neutralising antibodies. Potential connections between infection and development of disease are important questions for future studies.

Highlights

Vector-borne infections have a great impact on both human and animal health worldwide [1]
All samples were analysed by a Sindbis virus (SINV) plaque reduction neutralisation test (PRNT) using a 20× serum dilution and SINV-I strain 09-M-358-5, previously isolated from mosquitoes collected in central Sweden [14,15,16,17]
SINV-I infection in horses has been reported from South Africa, where SINV RNA was detected in the brains of horses showing neurological symptoms [11]

Summary

Introduction

Vector-borne infections have a great impact on both human and animal health worldwide [1]. Eastern equine encephalitis virus (EEEV), Western equine encephalitis virus (WEEV), all present in North America, Gheta virus (GV) present pre dominantly in Asia, and Ross River virus (RRV) present in Australia, as well as the flaviviruses; West Nile virus (WNV) and Japanese encepha litis virus (JEV). Many of these viruses target the central nervous system in both humans and horses, with neurological symptoms as a conse quence, sometimes with mortal outcome [2,3,4] for RRV the symptoms in both horses and humans mainly come from inflammation of the joints, and GV is mainly associated with a febrile disease [5,6,7]

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