E-mail addresses:
E-mail: chenluhau@126.com (Lu Chen);yangyu7712@sina.com (Yurong Yang)
Abstract: Here we described brain lesion in young captive lions after exhibiting ataxia. The histopathological analyses of the brain showed typical encephalitis with glial cell proliferation, neuronal atrophy and necrosis, and encephalomalacia. We used a variety of identification methods, including next-generation sequencing, polymerase chain reaction (PCR), virus isolation, immunofluorescence staining (IFA), and electron microscopy. Combined with clinical manifestations of the infected cub, it determined that the dead cub have resulted from an FPV embryonic infection. Through sequence analysis, it was found that the infected virus may be a recombinant virus between FPV and CPV. this study not only provides new gene sequences for the global study of FPV-infected lions but also helps to further study the incidence and genetic diversity of FPV.
KEYWORDS: Feline panleukopenia virus (FPV); young lions; hypogranular cerebellar; brain lesion; embryonic infection
INTRODUCTION
Feline panleukopenia is caused by a feline panleukopenia virus (FPV), which is a single-stranded DNA virus. Genetically, structurally, and antigenically, FPV is closely related to the mink enteritis virus (MEV), and canine parvovirus (CPV) (Truyen et al.,2013). FPV infections in primarily domesticated cats and wild felids, including tigers (Panthera Tigris) and lions (Panthera Leo) (Driciru et al., 2006; Duarte et al., 2009; Goodrich et al.,2012), have been described based on clinical, pathological, virologic, or molecular data. Previous studies show that the symptoms associated with FPV infection in tigers and lions are gastrointestinal enteritis and severe hemorrhagic enteritis, respectively (Wang et al.,2019; Wang et al., 2017); Evidence of neurological symptoms, such as ataxia, dysphagia, and hydrocephalus, has not been described in lions infected with FPV previously We, therefore describe previously undocumented neuropathologic changes and molecular features associated with FPV infection in lions.
In this study, we report an outbreak of fatal FPV infection among captive lions in the Zhengzhou Zoo in central China. The survey results showed that a total of 39 lion cubs were born between April 2017 to July 2019, and the cubs were of different ages and varying degrees of clinical characteristics. Miscarriage in the early stage of pregnancy in the lionesses resulted in 24 fetal deaths. Three cubs did not breast-feed at birth and died within a week following birth. Another 12 normally born cubs were placed in similar or adjacent rooms. Signs of limb weakness and walking instability began to appear at the age of 4-8 weeks. They were artificially fed with food and water, lost the ability to act independently and had difficulty swallowing when they were about a year old, and died of asphyxiation when eating meat. Besides, there were no other obvious clinical manifestations. The histopathologic findings, together with the sequencing analysis, virus isolations, PCR, IFA and Electron microscopy observation results, suggest that parvovirus was the cause of the death in these animals. This is the first time a case of recombination of CPV and FPV infection that caused lion brain tissue lesions and neurological symptoms has been found.
MATERIALS AND METHODS