Interstitial lung disease associated with Equine Infectious Anemia Virus infection in horses Pompei Bolfa, Marie Nolf, Jean-Luc Cadore, Cornel Catoi, Fabienne Archer, Christine Dolmazon, Jean-François Mornex, Caroline Leroux To cite this version: Pompei Bolfa, Marie Nolf, Jean-Luc Cadore, Cornel Catoi, Fabienne Archer, et al.. Interstitial lung disease associated with Equine Infectious Anemia Virus infection in horses. Veterinary Research, BioMed Central, 2013, 44, 10.1186/1297-9716-44-113. hal-02650848 HAL Id: hal-02650848 https://hal.inrae.fr/hal-02650848 Submitted on 29 May 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Distributed under a Creative Commons Attribution| 4.0 International License VETERINARY RESEARCH Interstitial lung disease associated with Equine Infectious Anemia Virus infection in horses Bolfa et al. Bolfa et al. Veterinary Research 2013, 44:113 http://www.veterinaryresearch.org/content/44/1/113 Bolfa et al. Veterinary Research 2013, 44:113 http://www.veterinaryresearch.org/content/44/1/113 VETERINARY RESEARCH RESEARCH Open Access Interstitial lung disease associated with Equine Infectious Anemia Virus infection in horses Pompei Bolfa5†, Marie Nolf1,2,3,6†, Jean-Luc Cadoré1,2,3,6, Cornel Catoi5, Fabienne Archer1,2,3, Christine Dolmazon1,2,3,4, Jean-François Mornex1,2,3,4 and Caroline Leroux1,2,3* Abstract EIA (Equine Infectious Anemia) is a blood-borne disease primarily transmitted by haematophagous insects or needle punctures. Other routes of transmission have been poorly explored. We evaluated the potential of EIAV (Equine Infectious Anemia Virus) to induce pulmonary lesions in naturally infected equids. Lungs from 77 EIAV seropositive horses have been collected in Romania and France. Three types of lesions have been scored on paraffin-embedded lungs: lymphocyte infiltration, bronchiolar inflammation, and thickness of the alveolar septa. Expression of the p26 EIAV capsid (CA) protein has been evaluated by immunostaining. Compared to EIAV-negative horses, 52% of the EIAV-positive horses displayed a mild inflammation around the bronchioles, 22% had a moderate inflammation with inflammatory cells inside the wall and epithelial bronchiolar hyperplasia and 6.5% had a moderate to severe inflammation, with destruction of the bronchiolar epithelium and accumulation of smooth muscle cells within the pulmonary parenchyma. Changes in the thickness of the alveolar septa were also present. Expression of EIAV capsid has been evidenced in macrophages, endothelial as well as in alveolar and bronchiolar epithelial cells, as determined by their morphology and localization. To summarize, we found lesions of interstitial lung disease similar to that observed during other lentiviral infections such as FIV in cats, SRLV in sheep and goats or HIV in children. The presence of EIAV capsid in lung epithelial cells suggests that EIAV might be responsible for the broncho-interstitial damages observed. Introduction of the seropositive animals and serological survey of all the Equine Infectious Anemia Virus (EIAV) is a retrovirus be- in-contact horses, the disease still spreads among horses. longing to the lentivirus genus, which infects equids world- EIAV infection is endemic in horse populations through- wide (reviewed in [1]). Persistent infection is characterized out the world [2] including recent outbreaks in Belgium, by recurring viremic febrile episodes. Clinical signs of EIA Germany, Greece, France, Italy, Romania and UK (source (Equine Infectious Anemia), the EIAV-induced disease, are OIE reports). Romania had to deal with more than 10 000 variable although infected equids often experience acute infected horses over the 2009–2012 period [3]. Relatively febrile episodes with concomitant thrombocytopenia and little is known about the origins, the viral characterization wasting syndrome followed by a chronic stage character- and the pandemic spread of the viruses [4,5]. ized by recurring disease episodes. In most cases, these fe- In experimentally-infected equids, active viral replication brile episodes eventually cease and despite remaining has been detected in various tissues such as spleen, liver, persistently infected the animals enter a prolonged phase lung, lymph nodes or bone marrow (reviewed in [1]), and with no overt clinical signs (reviewed in [1]). These in- viral tropism for mononuclear phagocytes is widely ac- apparent carriers are potential reservoirs for transmission cepted. As for other human and animal lentiviruses, the to naive equids. Despite a sanitary policy including culling cells of the monocyte/macrophage lineage represent the main targets of EIAV in vivo, supporting active viral repli- cation during clinical and subclinical infection [6]. EIAV * Correspondence: [email protected] viral RNAs have been also detected in vascular endothelial † Equal contributors cells in experimentally infected horses during the acute 1UMR754, Retrovirus and Comparative Pathology, INRA, Lyon, France 2Université Lyon 1, Lyon, France Full list of author information is available at the end of the article © 2013 Bolfa et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Bolfa et al. Veterinary Research 2013, 44:113 Page 2 of 9 http://www.veterinaryresearch.org/content/44/1/113 phase [7]. We recently demonstrated that EIAV is involved the Romanian EIAVNEG horses to constitute the control in the development of oxidative stress in horses [8]. group. We hypothesized that, as demonstrated with other len- tiviruses, EIAV may induced specific lung lesions. We Pathology systematically characterized lung lesions from paraffin Lungs were sampled from the mid dorsal part of the caudal embedded sections collected from 93 Romanian and lobe. Samples were fixed in 10% neutral buffered formalin French horses. We stained the lung for the expression of for at least 24 h at 4 °C, dehydrated in ascending concen- EIAV p26 capsid protein. In this study we described for trations (70, 95 and 100%) of ethanol, cleared in xylene, the first time an interstitial lung disease in EIAV infected and embedded in Histowax (Histo-Lab. Ltd, Gothenburg, horses as well as infection of lung epithelial cells. Sweden). Five μm thick serial sections were cut, deparaffi- nized, rehydrated with water in descending concentrations Materials and methods of ethanol (100, 95 and 70%) and used for HE (hematoxylin Animal source and tissue specimens and eosin) staining. Tissues were observed under a light Lungs from 93 horses have been collected for this study. microscope and a score was assigned according to the se- Seventyninelungs(#1to79)camefromEIAV-positive verityofthelesions,byblinded reading of the lung slides, (EIAVPOS) horses, mean age 10.65 years (± 5.43) and from accordingly to previously reported studies on the SRLV- 14 EIAV-negative (EIAVNEG) horses (# 80 to 93), mean age induced interstitial lung disease in sheep [9-11]. Three 9.73 years (± 5.14). Among the EIAVPOS horses, 77 (31 fe- types of lesions have been evaluated: lymphocyte infiltra- males and 46 males, mean age 10.58 years (± 5.47)) have tion i.e. presence or absence of inflammatory cells in the been collected in Romania (-rom) from October 2010 to lung parenchyma [A], (peri)bronchiolar inflammation [B] May 2011. They were serologically positive for EIAV as and thickness of the alveolar septa [C]. The bronchiolar in- confirmed by agar gel immunodiffusion test (AGID) or flammation was evaluated per ten random microscopic Coggins test (EIA Kit No. 119, Pasteur Institute) performed fields using a magnification of X100 and included five cat- by regional reference laboratories across the country in the egories: “0” for no lesions; “I” for mild lymphocyte inflam- context of the wide range National survey of EIAV in- mation around bronchiole; “II” for moderate lymphocyte fection among farm horses. Positive animals have been put infiltration around bronchiole and inside wall, epithelial to death according to the national plan for eradication of bronchiolar hyperplasia; “III” for moderate to severe EIA in Romania (Order No. 52/09.06.2010, ANSVSA lymphocyte infiltration, partial destruction of bronchiolar Bucharest, Romania). At that time, none of these animals epithelium, peribronchiolar muscle cells more visible and displayed clinical signs of EIA nor pulmonary disease as “IV” for destruction of bronchiolar lumen or epithelium re- assessed by a rapid examination; importantly no biologi- placed by fibrous/muscular layers with or without inflam- cal parameters (body temperature or blood cell counts) matory cells. The thickening of the alveolar septa was have been collected. Lungs from 2 EIAVPOS French horses evaluated according to the degree of interstitial accumula- (78-fr, 10 year-old female and 79-fr, 16-year old male) have tion of inflammatory cells