TITLE:
Epizootic, Endemic and Pandemic Zoonotic Viral Infections
AUTHORS:
Shravan Singh Rathore, Hem Singh Gehlot, Gyan Prakash, Jayashree S. Nandi
KEYWORDS:
Zoonotic Pathogens, Natural Infection, Anthroponosis, Migratory Birds Across Countries, Aquatic Demoiselle Cranes, Viral Infectious Diseases
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.10 No.3,
March
10,
2022
ABSTRACT: More than 60% human infectious diseases have zoonotic origin. Cross species transmission of pathogens is a continuous, dynamic process that occurs throughout the world, giving rise to epizootic (temporary, limited infection), endemic (on-going infection limited to a defined geographic region) and pandemic viral infections (infection spreading to every part of the world) like the current COVID-19 pandemic, which depends on the existing conditions on the ground. In Nov 2021, sudden mortality of numerous migrating demoiselle cranes was reported from their resting site near Jodhpur, Rajasthan. The symptomatic cranes became gradually weak and were unable to fly. They eventually fell dead which caused concern locally, given the current prevailing SARS-CoV-2 pandemic situation the world over. By the end of Dec 2021, the number of cranes with mortality and morbidity reduced, making it a temporary “epizootic infection”. Molecular diagnosis carried out at a specialized laboratory identified the etiological agent to be the highly pathogenic Avian Influenza Virus H5N1 (HPAIV), which has been responsible for morbidity of avian species from different parts of the world. There was no report of spreading the H5N1 AIV infection from the infected migratory cranes to nearby chicken farms or pig farms for now. In the absence of vaccines against the highly pathogenic H5N1 AIVs, and the inherent ability of influenza viruses, both avian AIV and human IAVs to constantly mutate its envelope gene or the surface antigens, resulting from the error-prone nature of the viral RNA Polymerase enzyme are the roadblocks for development of a universal, broad-spectrum influenza vaccine. Even when such a universal vaccine against H5N1 is available, vaccinating a large number of wild migratory cranes would be difficult. However, it is possible and indeed necessary to vaccinate chickens in poultry farms and pigs in farms that raise pigs for human consumption.