Low occurrence of equine herpesvirus 1 (EHV-1) as cause of abortion and perinatal mortality in Brazil

Aline Aparecida Da Silva,Carolina Natalia Zanuzzi,Enio Mori,Elenice Maria Sequetin Cunha,Claudia Del Fava,Maria Do Carmo Custódio De Souza Hunold Lara Lara,Cecília Mônica Galosi,Eliana Monteforte Cassaro Villalobos,Alessandra Figueiredo De Castro Nassar

doi:10.1590/1808-1657000852017

Aline Aparecida Da Silva, Carolina Natalia Zanuzzi + Show 7 more

Open Access

https://doi.org/10.1590/1808-1657000852017

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Abstract

ABSTRACT: Equine herpesvirus type 1 (EHV-1) is an important pathogen that causes abortion, neonatal disease, respiratory disorders, and neurological syndrome in equine populations worldwide. To evaluate EHV-1 as a cause of abortion and perinatal mortality in Brazil, tissue samples from 105 aborted equine fetuses, stillbirths, and foals up to one month of age were examined using virus isolation, immunohistochemistry (IHC), histopathology, and nested polymerase chain reaction (PCR). Two fetuses were positive for EHV-1 by PCR, one of which showed syncytia and eosinophilic intranuclear inclusion bodies in bronchial epithelia, but it was negative by virus isolation. The other showed no characteristic histological lesions, but it was positive by viral isolation. No sample was positive by IHC. The results presented low occurrence of EHV-1 in the studied population and suggested that the use of a combination of techniques increases the likelihood of an accurate diagnosis of EHV-1.

Highlights

Equine herpesvirus type 1 (EHV-1), an enveloped virus that causes respiratory and neurological clinical signs, abortion, and neonatal death, has been isolated from aborted equine fetuses in Brazil and other areas throughout the world (HONG et al, 1993; MOREIRA et al, 1998; LAUGIER et al, 2011)
The virus is transported by B and T lymphocytes to the uterus and other organs via circulatory system (RUIZSÁENZ et al, 2008), potentially leading to severe vasculitis and multifocal endometrial thrombosis that may cause abortion in the final trimester of pregnancy, perinatal death, and/ or myeloencephalopathy and neurological syndrome in the foal (CRABB; STUDDERT, 1995; ALLEN, 2002; RUIZSÁENZ et al, 2008)
Several factors complicate accurate diagnosis of EHV-1, including the overlap of respiratory and neurological clinical signs with diseases induced by other pathogens, for example, equine influenza virus subtypes 1 and 2 and equine adenovirus type 1, which cause respiratory infection; equine viral arteritis associated with respiratory disease and abortion; the protozoan Sarcocystis neurona; and the rabies virus causing neurological disorders (MCCHESNEY et al, 1970; SMITH, 1993; FERNANDES, 1999)

Summary

Introduction

Equine herpesvirus type 1 (EHV-1), an enveloped virus that causes respiratory and neurological clinical signs, abortion, and neonatal death, has been isolated from aborted equine fetuses in Brazil and other areas throughout the world (HONG et al, 1993; MOREIRA et al, 1998; LAUGIER et al, 2011). Pathological lesions of liver, kidney, heart, lung, spleen, and brain of fetuses aborted due to EHV-1 infection are characterized by mononuclear inflammatory infiltrate and focal necrosis (DEL PIERO, 1999; OIE, 2015).

Results

Conclusion