Experimental pathology of two highly pathogenic H5N1 viruses isolated from crows in BALB/c mice

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Microb Pathog. 2020 Jan 20:103984. doi: 10.1016/j.micpath.2020.103984. [Epub ahead of print] Experimental pathology of two highly pathogenic H5N1 viruses isolated from crows in BALB/c mice.

Kombiah S¹, Kumar M², Murugkar HV³, Nagarajan S³, Tosh C³, Senthil Kumar D³, Rajukumar K³, Gautam S¹, Singh R¹, Karikalan M¹, Sharma AK¹, Singh VP³.
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Abstract

In our study we assessed the pathogenicity of two H5N1 viruses isolated from crows in mice. Eighteen 6-8 weeks BALB/c mice each were intranasally inoculated with 10⁶ EID₅₀/ml of H5N1 viruses A/crow/India/03CA04/2015 (H9N2-PB2 reassortant H5N1) and A/crow/India/02CA01/2012 (Non-reassortant H5N1). The infected mice showed dullness, weight loss and ruffled fur coat. Histopathological examination of lungs showed severe congestion, haemorrhage, thrombus, fibrinous exudate in perivascular area, interstitial septal thickening, bronchiolitis and alveolitis leading to severe pneumonic changes and these lesions were less pronounced in reassortant virus infected mice. Viral replication was demonstrated in nasal mucosa, lungs, trachea and brain in both the groups. Brain, lung, nasal mucosa and trachea showed significantly higher viral RNA copies and presence of antigen in immunohistochemistry in both the groups. This study concludes that both the crow viruses caused morbidity and mortality in mice and the viruses were phenotypically highly virulent in mice. The H5N1 viruses isolated from synanthropes pose a serious public health concern and should be monitored continuously for their human spill-over.
Copyright ? 2020. Published by Elsevier Ltd.


KEYWORDS:

Avian influenza; BALB/c mice; Crow isolates; H9N2-PB2 reassortant H5N1

PMID: 31972269 DOI: 10.1016/j.micpath.2020.103984