Phylomolecular and Gross Pathological Characterization of Avian Influenza Virus from Poultry Farms in Pampanga, Philippines

Date

2024

Degree

Doctor of Veterinary Medicine

Adviser/Committee Chair

Dennis V. Umali

Co-adviser

Fletcher P. Del Valle

Abstract

Background: Highly pathogenic avian influenza (HPAI) virus has been spreading rapidly across the globe, and with the neighboring countries of the Philippines already infected this brings a threat to the poultry industry of the country. Stringent surveillance and appropriate diagnosis of possible cases of AIV must be implemented. Unusual cases of high mortality in a short period of time, must be tested for the said virus. Methods: FTA cards containing cloacal and oropharyngeal swabs of a flock with a history of high mortality in a short period of time were tested for HPAI using RT-PCR. The virus isolated was then put to nucleotide sequencing and phylogenetic analysis to identify the possible origin and relatedness to other strains of HPAI viruses. Gross lesions and histopathological examination were also done on morbid chickens belonging to the said flock. Results: RT-PCR revealed that the viruses were of the H5N1 subtype. Nucleotide sequencing and phylogenetic analysis indicated that these viruses, namely A/quail/Pampanga/SanLuis/2022 (H5N1) and A/chicken/Pampanga/SanLuis/2022 (HSN1), were of distinct identities. These virus isolates were closely related to the circulating clade 2.3.4.4b H5N1 circulating in Korea, Japan, Europe, and USA. Gross and histopathologic lesions mainly concerned the vascular system with congestion and hemorrhage as the most prevalent abnormalities. Conclusion: The highly pathogenic virus has now been introduced to the Philippines, and given its molecular epidemiological characteristics, there is high likelihood that it has spread throughout the country. National and regional surveillance must be enhanced to control the spread of the isolated virus.

Language

English

Location

UPLB College of Veterinary Medicine (CVM)

Notes

Awards: Robert H. Lo Best Undergraduate Thesis Award on Poultry

Document Type

Thesis

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