title: Pathology of Equine Influenza virus (H3N8) in Murine Model.
abstract: Equine influenza viruses (EIV)-H3N8 continue to circulate in equine population throughout the world. They evolve by the process of antigenic drift that leads to substantial change in the antigenicity of the virus, thereby necessitating substitution of virus strain in the vaccines. This requires frequent testing of the new vaccines in the in vivo system; however, lack of an appropriate laboratory animal challenge model for testing protective efficacy of equine influenza vaccine candidates hinders the screening of new vaccines and other therapeutic approaches. In the present investigation, BALB/c mouse were explored for suitability for conducting pathogenecity studies for EIV. The BALB/c mice were inoculated intranasally @ 2×106.24 EID50 with EIV (H3N8) belonging to Clade 2 of Florida sublineage and monitored for setting up of infection and associated parameters. All mice inoculated with EIV exhibited clinical signs viz. loss in body weights, lethargy, dyspnea, etc, between 3 and 5 days which commensurate with lesions observed in the respiratory tract including rhinitis, tracheitis, bronchitis, bronchiolitis, alveolitis and diffuse interstitial pneumonia. Transmission electron microscopy, immunohistochemistry, virus quantification through titration and qRT-PCR demonstrated active viral infection in the upper and lower respiratory tract. Serology revealed rise in serum lactate dehydrogenase levels along with sero-conversion. The pattern of disease progression, pathological lesions and virus recovery from nasal washings and lungs in the present investigations in mice were comparable to natural and experimental EIV infection in equines. The findings establish BALB/c mice as small animal model for studying EIV (H3N8) infection and will have immense potential for dissecting viral pathogenesis, vaccine efficacy studies, preliminary screening of vaccine candidates and antiviral therapeutics against EIV.
authors.affiliation: National Research Centre on Equines, Hisar, Haryana, India.
authors.forename: Selvaraj
authors.initials: S
authors.lastname: Pavulraj
authors.affiliation: National Research Centre on Equines, Hisar, Haryana, India.
authors.forename: Bidhan Chandra
authors.initials: BC
authors.lastname: Bera
authors.affiliation: Veterinary Hospital-Naini, Barakot, Almora, Uttarakhand, India.
authors.forename: Alok
authors.initials: A
authors.lastname: Joshi
authors.affiliation: National Research Centre on Equines, Hisar, Haryana, India.
authors.forename: Taruna
authors.initials: T
authors.lastname: Anand
authors.affiliation: Department of Veterinary Physiology and Biochemistry, Lala Lajpat Rai University of Veterinary & Animal Sciences, Hisar, Haryana, India.
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Virmani
authors.affiliation: National Research Centre on Equines, Hisar, Haryana, India.
authors.forename: Rajesh Kumar
authors.initials: RK
authors.lastname: Vaid
authors.affiliation: National Research Centre on Equines, Hisar, Haryana, India.
authors.forename: Karuppusamy
authors.initials: K
authors.lastname: Shanmugasundaram
authors.affiliation: National Research Centre on Equines, Hisar, Haryana, India.
authors.forename: Baldev Raj
authors.initials: BR
authors.lastname: Gulati
authors.affiliation: National Institute of High Security Animal Diseases, Bhopal, MP, India.
authors.forename: K
authors.initials: K
authors.lastname: Rajukumar
authors.affiliation: Division of Pathology, Indian Veterinary Research Institute, Bareilly, UP, India.
authors.forename: Rajendra
authors.initials: R
authors.lastname: Singh
authors.affiliation: Division of Animal Science, Krishi Bhavan, New Delhi, India.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Misri
authors.affiliation: Indian Veterinary Research Institute, Bareilly, UP, India.
authors.forename: Raj Kumar
authors.initials: RK
authors.lastname: Singh
authors.affiliation: National Research Centre on Equines, Hisar, Haryana, India.
authors.forename: Bhupendra Nath
authors.initials: BN
authors.lastname: Tripathi
authors.affiliation: National Research Centre on Equines, Hisar, Haryana, India.
authors.forename: Nitin
authors.initials: N
authors.lastname: Virmani
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006734:Horse Diseases / Q000473:pathology / Q000821:virology*; D006736:Horses / Q000821:virology; D053123:Influenza A Virus, H3N8 Subtype / Q000276:immunology / Q000472:pathogenicity*; D051379:Mice; D009976:Orthomyxoviridae Infections / Q000473:pathology / Q000821:virology*