Epidemiology of the highly pathogenic avian influenza (HPAI) H5N6 and H5N8 in poultry in Quang Ninh Province, Vietnam from 2020 to 2021

Name: Trong, Tran Duc

LCSH: Kasetsart University -- Theses. M.S. (Veterinary Epidemiology) 2023

Classification :.LCCS: SF995.6.I6

LCSH: Kasetsart University. -- Department of Veterinary Epidemiology -- Theses

LCSH: Avian influenza -- Vietnam -- Quang Ninh

LCSH: Avian influenza -- Epidemiology

LCSH: Poultry -- Virus diseases

Abstract: Avian influenza (AI) is a contagious disease that can cause illness and death in both poultry and humans. Highly pathogenic avian influenza (HPAI) H5N6 outbreaks have occurred annually in Quang Ninh province, a province bordering China. In June 2021, the first outbreak of HPAI H5N8 occurred at a chicken farm in Quang Ninh province. This study determined risk factors associated with HPAI outbreaks and described the molecular epidemiology of the HPAI H5N6 and H5N8 strains in Quang Ninh province, Vietnam. Firstly, we conducted a retrospective case-control study with all thirty-eight reported poultry farms recruited as cases and 112 surrounding infected households as controls. Logistic regression models were built to assess risk factors associated with HPAI outbreaks at a household level. The positive samples by Real-time RT-PCR were sequenced and analyzed for HPAI virus characterization. Three significant risk factors were identified: Raising poultry in uncovered or partially covered ponds (OR =11.87, 95%CI:1.99–70.1); poultry traders visiting a poultry farm (OR=11.12, 95%CI:3.4– 36.35); and poultry farms located less than 500 meters from a river (OR=4.05, 95%CI:1.32–12.37). During the study, period HPAI occurred in all 38 households in 13 communes in 7 districts. A total of 69,057 poultry were culled. Of these, 35 HPAI outbreaks were caused by H5N6 clade 2.3.4.4h, and three outbreaks were caused by H5N8 clade 2.3.4.4b. Secondly, a case-control study was conducted also to find out the factors that affected AI vaccination. We interviewed 71 households that used AI vaccines in a survey, 16 veterinary drug stores, 18 commune animal health workers (CAHWs), 8 Agricultural Technical Service Centers (ATSCs), and 1 vaccine distributor. We found that ATSCs were an important role in the cool storing and AI vaccination, some AI vaccines sold on the farm were not fitted for the H5N6 virus found in Quang Ninh province from 2020 to 2021. Finally, we conclude that understanding the molecular epidemiology of HPAI viruses can lead to the identification of the most effective AI vaccine. Combined biosafety and security measures will enhance the efforts to control and prevent HPAI in Quang Ninh province.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Suwicha Kasemsuwan

Role: Thesis Advisor

Name: Manakorn Sukmak

Role: Thesis CO-Advisor

Created: 2023

Modified: 2025-07-25

Issued: 2025-07-25

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2566/tran-duc-all.pdf

CallNumber: SF995.6.I6 .T74

eng

Spatial: Vietnam Quang Ninh.

DegreeName: Master of Science

Level: Master's Degree

Descipline: Veterinary Epidemiology

Grantor: Kasetsart University

©copyrights Kasetsart University

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