A retrospective pathology study of two Neotropical deer species (1995-2015), Brazil: Marsh deer (Blastocerus dichotomus) and brown brocket deer (Mazama gouazoubira).

Pedro Enrique Navas-Suárez,Cinthya Dos Santos-Cirqueira,Adriana Marques Joppert,Jose Mauricio Barbanti Duarte,Bruno Cogliati,Leonardo Mesquita,Carlos Sacristán,Paulo César Maiorka,Ana Carolina Ewbank,José Luiz Catão-Dias,Cintia Maria Fávero,Josué Díaz-Delgado,Angélica Maria Sánchez Sarmiento,Eliana Reiko Matushima,Christopher James Johnson

doi:10.1371/journal.pone.0198670

Abstract

This retrospective study describes the biological and epidemiological aspects, gross and microscopical findings, and most likely causes of death (CD) in two species of Neotropical deer in Brazil. The animals were collected between 1995 and 2015 and represented 75 marsh deer (MD) and 136 brown brocket deer (BBD). Summarized, pneumonia was diagnosed microscopically in 48 MD and 52 BBD; 76 deer suffered trauma, involving dog attack (14 BBD) and vehicle-collision (14 BBD). Pulmonary edema (50 MD; 55 BBD) and congestion (57 MD; 78 BBD) were the most common findings for both species. Additionally, we diagnosed ruminal and myocardial mycosis in MD and BBD, respectively; ovarian dysgerminoma and pancreatic trematodiasis in BBD; and lesions suggestive of malignant catarrhal fever and orbiviral hemorrhagic disease in both species. The main CD in MD was: respiratory (41/75), alimentary, nutritional, trauma and euthanasia (3/75 each). Correspondingly, in BBD were: trauma (34/131), respiratory (30/131) and euthanasia (9/131). Respiratory disease was often defined by pulmonary edema and pneumonia. We provide evidence that respiratory disease, mainly pneumonia, is a critical pathological process in these Neotropical deer species. Although no etiological agents were identified, there is evidence of bacterial and viral involvement. Our results show trauma, mainly anthropogenic, as a common ailment in BBD. We propose to prioritize respiratory disease in future research focused on South American deer health aspects. We believe anthropogenic trauma may be a primary threat for populations of BBD.

Highlights

In wildlife, diseases may lead to population decline [1,2,3]
Diseases introduced by livestock (e.g., foot and mouth disease (FMD), brucellosis, babesiosis and several ecto- and endoparasitoses) are considered threats to the conservation of the eight-deer species currently found in Brazil [18]
Health studies in South American deer species have mainly focused on serological surveys, e.g., brown brocket deer (BBD; Mazama gouazoubira) in Bolivia [19], Argentinean Pampas deer (Ozotoceros bezoarticus) [20], and several studies of free-ranging and captive Brazilian deer populations [21,22,23,24,25,26]

Summary

Introduction

Mainly the white-tailed deer (WTD; Odocoileus virginianus), have been extensively studied, with reports of infectious (prion, viral, bacterial, fungal, parasitic) and non-infectious diseases (e.g., toxicities, nutritional and metabolic disorders, neoplasia) [4,5]. Zoonotic and non-zoonotic examples of infectious diseases in wild ruminants with major socio-economic implications include: foot and mouth disease (FMD) in WTD [8,9]; bluetongue (BT) in WTD and red deer (Cervus elaphus) [10,11]; bovine viral diarrhea (BVD) in WTD [12,13]; chronic wasting disease in WTD [14]; and brucellosis in several North American deer species [15]. Health studies in South American deer species have mainly focused on serological surveys, e.g., brown brocket deer (BBD; Mazama gouazoubira) in Bolivia [19], Argentinean Pampas deer (Ozotoceros bezoarticus) [20], and several studies of free-ranging and captive Brazilian deer populations [21,22,23,24,25,26]

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Results

Conclusion