Equine Multinodular Pulmonary Fibrosis in association with asinine herpesvirus type 5 and equine herpesvirus type 5: a case report

Helena Back,Anna Kendall,Louise Treiberg-Berndtsson,John Pringle,Karin Ullman,Karl Ståhl,Rodrigo Grandón

doi:10.1186/1751-0147-54-57

Abstract

A standardbred gelding with a history of 10 days pyrexia and lethargy was referred to the Equine Hospital at the Swedish University of Agricultural Sciences in Uppsala, Sweden.The horse had tachypnea with increased respiratory effort and was in thin body condition. Laboratory findings included leukocytosis, hyperfibrinogenemia and hypoxemia. Thoracic radiographs showed signs of pneumonia with a multifocal nodular pattern, which in combination with lung biopsy findings indicated Equine Multinodular Pulmonary Fibrosis (EMPF). EMPF is a recently described disease in adult horses with clinical signs of fever, weight loss and respiratory problems. The pathological findings include loss of functional pulmonary parenchyma due to extensive nodular interstitial fibrosis which has been related to infection with the equine herpesvirus type 5 (EHV-5). In this case, lung biopsy and tracheal wash samples tested positive for both asinine herpesvirus type 5 (AHV-5) and EHV-5 using PCR assays. The horse failed to respond to treatment and was euthanized for humane reasons. Postmortem examination confirmed the diagnosis of EMPF. This case suggests that not only EHV-5 alone should be considered in association with the development of this disease.

Highlights

Equine herpesvirus type 5 (EHV-5) is one of the nine herpesviruses known to infect Equidae [1]
Phylogenetic analysis was performed on the overlapping fragments of asinine herpesvirus type 5 (AHV-5) and EHV-5 and related equine herpesviruses sequences obtained from GenBank (virus/ accession number: EHV-2/HQ247790, EHV-5/GQ325597, EHV-7/EU165547, asinine herpesviruses (AHV)-5/FJ798319, Zebra Herpesvirus/ AF141889, Wild Ass Herpesvirus (WAHV)/AF141888, and Eastern Kiang herpesvirus/EU717156 incorrectly denominated EHV-9 in GenBank) using Neighbourjoining and the Kimura-two-parameter model as implemented in SplitTree4 [22] clearly confirming the close relation between the sequences obtained with AHV-5 and EHV-5, respectively (Figure 3)
This case report describes a horse with clinical signs and histological changes within the lung that correspond with the recently described disease Equine Multinodular Pulmonary Fibrosis (EMPF) [11] that has been associated with infection by EHV-5

Summary

Background

Equine herpesvirus type 5 (EHV-5) is one of the nine herpesviruses known to infect Equidae [1]. Histological examination of lung tissue include multiple, well-demarcated nodular regions of pulmonary interstitial fibrosis with mixed inflammatory cell infiltration. What is striking in this case is the apparent co-infection with AHV-5 and EHV- 5 Both viruses were detected by PCR in samples from lung tissue and tracheal wash. Histological examination (Figure 2) of the lung tissue with hematoxylin-eosin (HE) and Massons trichrome stained sections demonstrated a moderate to severe, multifocal to coalescing interstitial fibrosis with presence of mature collagen. PCR and sequence analysis The clinical signs, findings at necropsy and absence of other pathogens corresponded well with EMPF, and samples from lung tissue and tracheal wash were submitted for further virus examination. Phylogenetic analysis was performed on the overlapping fragments of AHV-5 and EHV-5 and related equine herpesviruses sequences obtained from GenBank (virus/ accession number: EHV-2/HQ247790, EHV-5/GQ325597, EHV-7/EU165547, AHV-5/FJ798319, Zebra Herpesvirus/ AF141889, Wild Ass Herpesvirus (WAHV)/AF141888, and Eastern Kiang herpesvirus/EU717156 incorrectly denominated EHV-9 in GenBank) using Neighbourjoining and the Kimura-two-parameter model as implemented in SplitTree4 [22] clearly confirming the close relation between the sequences obtained with AHV-5 and EHV-5, respectively (Figure 3)

Conclusions

24. Wilkins PA