A novel orally infected hamster model for Coxsackievirus A16 hand-foot-and-mouth disease and encephalomyelitis

• Main Authors: Hooi, Yuan Teng, Ong, Kien Chai, Tan, Soon Hao, Perera, David, Wong, Kum Thong
• Format: Article
• Published: Elsevier 2020
• Subjects: R Medicine (General); RB Pathology
• Online Access: http://eprints.um.edu.my/36599/

Coxsackievirus A16 (CV-A16) is one of the major causes of mild and self-limiting hand-foot-and-mouth disease (HFMD) in young children, which may occasionally leads to serious neurological complications. In this study, we had developed a novel, consistent, orally infected CV-A16 HFMD hamster model with encephalomyelitis. Four groups of 7-day-old hamsters in a kinetic study were orally infected with mouse-adapted CV-A16 strains and sacrificed at 1-4 days post infection (dpi), respectively. Tissues were studied by light microscopy, immunohistochemistry to detect viral antigens, in situ hybridization to detect viral RNA, and by viral titration. In a separate transmission experiment, orally infected index hamsters were housed together with contact hamsters to investigate oral and fecal viral shedding by virus culture and reverse transcription polymerase chain reaction (RT-PCR). At severe infection/death endpoints, index and contact hamster infection were also histopathologically analyzed. In the kinetic study, infected hamsters developed signs of infection at 4 dpi. Viral antigens/RNA were localized to brainstem (medulla/pons; reticular formation and motor trigeminal nucleus) and spinal cord anterior horn neurons, oral squamous epithelia and epidermis from 3 to 4 dpi. Salivary and lacrimal glands, myocardium, brown adipose tissue, intestinal smooth muscle, and skeletal muscle infection was also demonstrated. Viremia at 1 dpi and increasing viral titers in various tissues were observed from 2 dpi. In the transmission study, all contact hamsters developed disease 3-5 days later than index hamsters, but demonstrated similar histopathological findings at endpoint. Viral culture and RT-PCR positive oral washes and feces confirmed viral shedding. Our hamster model, orally infected by the natural route for human infection, confirmed CV-A16 neurotropism and demonstrated squamous epitheliotropism reminiscent of HFMD, attributes not found in other animal models. It should be useful to investigate neuropathogenesis, model person-to-person transmission, and for testing antiviral drugs and vaccines. An orally infected hamster model of Coxsackievirus A16 (CV-A16) hand-foot-and-mouth disease (HFMD) and encephalomyelitis demonstrating central nervous system and squamous epithelial infection, reminiscent of complicated human CV-A16 HFMD is described. This novel and consistent animal model should be useful to investigate viral pathogenesis, model person-to-person transmission, and to test antivirals and vaccines.