Equine grass sickness confirmed in case series in Italy

Equine grass sickness is likely to be underdiagnosed and its incidence underestimated in Italy, according to researchers.
Equine grass sickness is likely to be underdiagnosed and its incidence underestimated in Italy, according to researchers.

Equine grass sickness in Italy could be underdiagnosed and its incidence underestimated, according to researchers.

Equine grass sickness was first reported in Eastern Scotland in the early 1900s and then throughout Britain. The disease has also been reported in several European countries, including the Czech Republic, Belgium, Hungary, Austria, Switzerland, The Netherlands, Germany, France, Denmark and Cyprus. Suspected cases have been reported in the Falkland Islands and Australia.

It has recently been described in a mule in the United States. In South America, a disease caused mal seco has similar clinical signs.

The disease, also known as equine dysautonomia, affects almost exclusively horses kept on pasture. It can present as three different syndromes, recognized through clinical signs that are severe in the acute form, moderate in the sub-acute form, and mild in the chronic form.

Clinical signs are generally related to lesions in the autonomic nervous system, particularly in the nervous system relating to the gut.

The various symptoms include dullness, lack of appetite, difficulty swallowing, drooling of saliva, a fast heart rate, eyelid drooping, patchy sweating and muscle twitching. In acute cases, there can be mild to moderate abdominal pain and large volumes of nasogastric reflux.

The cause is still speculative and many hypotheses have been proposed.

Laus Fulvio and his fellow researchers, reporting in the journal BMC Veterinary Research, described a series of four cases of equine grass sickness — one subacute and three chronic — that occurred in Central Italy in early spring. The horses were aged 2 to 6.

In all cases, the prognosis was poor and the horses were euthanized. Diagnosis of equine grass sickness was confirmed by microscopic examination of tissue samples from the autonomic nervous system or enteric nervous system.

The signs shown by the horses were consistent with a diagnosis of either chronic or sub-acute equine grass sickness, the researchers said.

They said they believe their case reports represent the first confirmation of equine grass sickness in Italy. The disease could be underdiagnosed and its incidence underestimated in Italy, they said.

There should be greater awareness among Italian veterinarians to consider equine grass sickness as a possible diagnosis in horses with clinical signs of abdominal pain, whether or not it is associated with gastric reflux and muscular twitching.

All the cases in this study concerned horses kept in the same pasture, confirming possible premises-related and management-linked factors in the development of the disease.

Previous suspected diagnosis of the condition in the same livestock and recent cool dry weather were considered additional potential risk factors.

“Environmental and climatic conditions typical of Central Italy should be strongly considered as risk factors, also in other geographical regions of the country,” they said.

The study team comprised Fulvio, Bazzano Marilena and Bertoletti Alice, all with the University of Camerino; Mandara Maria Teresa and Gialletti Rodolfo, with the University of Perugia; and Corsalini Jacopo, a practitioner in Perugia.

Fulvio, L., Jacopo, C., Teresa, M.M. et al. Equine grass sickness in italy: a case series study. BMC Vet Res 17, 264 (2021). https://doi.org/10.1186/s12917-021-02966-y

The study, published under a Creative Commons License, can be read here


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