RESEARCH ARTICLE Sub-lethal Dose of Atropine Gives Protection from Japanese Encephalitis Virus Infection in Chick Embryo Model Urmita Chakraborty 1 • Moonmoon Sinha 1 • Arghyadeep Bhattacharjee 1 • Debadatta Nayak 2 • Anil Khurana 2 • Raj Kumar Manchanda 2 • Debabrata Sarkar 1 • Satadal Das 1 Received: 14 November 2018 / Revised: 25 September 2019 / Accepted: 17 February 2020 Ó Zoological Society, Kolkata, India 2020 Abstract Japanese encephalitis (JE) is now a public health concern due to limitation of the available vaccine and nonexistence of specific antiviral therapy and thus demands new potential therapeutical strategies. The present study was conducted to evaluate the effect of atropine in con- trolling JE virus infection in chick embryo, which is already established as an ideal model for study of various host–pathogen interactions and screening of newer antivi- ral agents. In this experiment we pre-treated 12 day old embryos with atropine sulphate to see whether it can give protection from JE virus challenge. There were significant decrease in the viral loads in the brain, chorioallantoic membrane and amniotic fluid of the embryo in atropine sulphate pre-treated groups compared to the infection groups. Atropine sulphate pre-treated group showed sig- nificant up-regulation of interferon alpha and toll like receptor-3 mRNA, than other analogous groups. The his- tological changes showed significant reduction of necrosis, inflammation and other co-morbid pathology in the atro- pine sulphate pre-treated groups. Hence this study demonstrated the protective role of atropine in controlling the JE virus replication and its organ-tropic dissemination to brain which may pave way for a prospective therapy in the future treatment of JE. Keywords Atropine Á Japanese encephalitis Á Embryonated egg Á Chorioallantoic membrane Introduction Japanese encephalitis virus (JEV), a neurotropic flavivirus, is the leading cause of mortality among all the viral encephalitis worldwide. Previously JE was considered to be a vaccine preventable disease. However, emergence of new genotypes of JEV during the last few years has pointed out the limited efficacy of the available vaccine and has become a serious challenge for animal and human health (Cao et al. 2016). Chicken and other domestic birds may act as carrier and amplifying host plays an important role in zoonosis (in the endemic area) by transmission of JE to human (Cleton et al. 2014; Adi et al. 2016). Unfortunately there is no antiviral drug available against JE. Thus novel antiviral therapy is highly coveted to protect both animal and human against the infection. Various studies are in progress for the search of new antiviral agents for combating the infection (Saxena et al. 2014; Fan et al. 2016; Wang et al. 2017a, b). Although atropine belongs to the anticholinergic group of agent and is generally used for muscarinic antagonist effect (De Elio 1948), its antiviral effect has been explored against various DNA and RNA virus including Herpes Simplex virus (HSV) and Hepatitis A virus. However, the effect of atropine against flavivirus including JE has not been studied till date. One of the common natural sources of atropine is Atropa belladonna. The antiviral property of ultradiluted extract of A. belladonna ( \ 1 pg/ml) has already been studied by us (Chakraborty et al. 2018). Embryonated egg of chicken is an excellent well established and cheapest in vivo system for host–pathogen interaction study in JEV. The high vascularised system of & Satadal Das drsatdas@hotmail.com 1 Department of Virology, Dr. Anjali Chatterjee Regional Research Institute for Homoeopathy, Ministry of AYUSH, Govt. of India, Kolkata 700035, India 2 Central Council for Research in Homoeopathy, Ministry of AYUSH, Govt. of India, New Delhi 110058, India 123 Proc Zool Soc https://doi.org/10.1007/s12595-020-00324-8 T H E Z O O L O G I C A L S O C I E T Y K O L K A T A