Newcastle disease burden in Nepal and efficacy of Tablet I2 vaccine in commercial and backyard poultry production

Abstract

Poultry (Gallus domesticus) farming plays an important role as an income generating enterprise in a developing country like Nepal, contributing more than 4% to the national Gross Domestic Product (GDP). Newcastle Disease (ND) is a major poultry disease affecting both commercial and backyard poultry production worldwide. There were more than 90 reported ND outbreaks in Nepal in 2018 with over 74,986 birds being affected. ND is responsible for over 7% of total poultry mortality in the country. Recent outbreaks of ND in 2021 affected many farms throughout Nepal and caused massive loss in poultry production. ND is caused by a single-stranded ribonucleic acid (RNA) virus that presents very similar clinical symptoms as Influenza A (commonly known as bird flu) adding much complexity to clinical disease identification and intervention. We conducted a nationwide ND and Influenza A (IA) prevalence study, collecting samples from representative commercial and backyard poultry farms from across the major poultry production hubs of Nepal. We used both serological and molecular assessments to determine disease exposure history and identification of strains of ND Virus (NDV). Of the 40 commercial farms tested, both NDV (n = 28, 70%) and IAV (n = 11, 27.5%) antibodies were detected in majority of the samples. In the backyard farms (n = 36), sero-prevalence of NDV and IAV were 17.5% (n = 7) and 7.5% (n = 3) respectively. Genotype II NDV was present in most of the commercial farms, which was likely due to live vaccine usage. We detected never reported Genotype I NDV in two backyard farm samples. Our investigation into 2021 ND outbreak implicated Genotype VII.2 NDV strain as the causative pathogen. Additionally, we developed a Tablet formulation of the thermostable I2-NDV vaccine (Ranigoldunga™) and assessed its efficacy on various (mixed) breeds of chicken (Gallus domesticus). Ranigoldunga™ demonstrated an overall efficacy >85% with a stability of 30 days at room temperature (25°C). The intraocularly administered vaccine was highly effective in preventing ND, including Genotype VII.2 NDV strain.

Complete genome sequence of a novel isolate of avian orthoavulavirus serotype 1 from Himalayan Griffon vulture

“…NDV is still spreading among birds, both in captivity and in the wild, promoting the formation of new and varied genetic variations [13] . Several investigations have been conducted on NDV epidemics in commercial chickens [3,[19][20][21]26] . However, NDV isolated in other species and their diversity has received less attention, which could lead to unchecked NDV transmission and the potential threat of an outbreak.…”

Antimicrobial stewardship hindered by inadequate biosecurity and biosafety practices, and inappropriate antibiotics usage in poultry farms of Nepal–A pilot study

“…Similar trend was observed in another study that analyzed commercial poultry in 10 districts of Nepal, in which, only 10% of the farms had comprehensive biosafety protection for the farmers. They were aware of the need for biosafety and biosecurity measures on a farm and had some form of personal protective equipment (PPE) and disinfecting agents but were inadequate [15].…”

Seroconversion study of thermostable NDI-2 vaccine at the free-ranging village chickens in two localities of South-central Niger

“…Vaccination trials of village chickens with vaccines based on I-2 strains selected by the Australian Center for International Agricultural Research (ACIAR) have been successfully conducted in several African and Asian countries (Adwar and Lukešová 2008;Nega et al, 2012;Acharya et al, 2019). In addition to their efficiencies, these vaccines also offer the potential to be administered through many routes such as eye drops, in drinking water, or in the diet (Thekisoe et al, 2004;Napit et al, 2023).…”