Information of PhD candidate Do Van Khien’s thesis


The title of thesis: “Study on some biological characteristics of the Goat Pox viruses isolated from South Central Region of Vietnam”

Subject: Veterinary Microbiology  Code: 62 62 50 10

Full name of PhD candidate: Do Van Khien

Full name of the supervisors:

1. Pham Hung DVM, PhD

2. Assoc.Prof. Le Thanh Hoa DVM, MSc, PhD

Training institution: National Institute Veterinary Research

The brief conclusion of the thesis

1. We isolated seven goat poxvirus strains from seven distinct out break in Ninh Thuan, Khanh Hoa and Phu Yen provinces in the South central region of Vietnam and confirmed by analysis of sequence of P32 gene, they belong to goat poxvirus.

2. The molecular characteritics of gene encoding P32 polypeptide (capsular protein) of the virus strains isolated from the South central region of Vietnam:

– Among the isolated strains, 99.90% – 100% similarity at the nucleotide level and 99.68% – 100% similarity at the amino acid level. The mutation of nucleotide was obsevered at one position of the P32 gene that induces the changes one amino acid in two out of seven isolated strains.

– The sequence of p32 gene of the goat poxvirus strains showed highly conserved among seven isolated strains as well as other strains from South and North of Vietnam. The sequence of P32 gene of isolated strains shared highly similarity with other goat poxvirus strains listed in GenBank (98.25% – 100% similarity at the nucleotide level and 97.20% – 100% similarity at the amino acid level).

– Based on the phylogenetic result, the goat poxvirus strains in Vietnam were origined from Chinese strains.

3. The goat poxvirus strains in the South central region of Vietnam have biological characteritics as follow:

– The isolated goat poxvirus strais were adapted in primary lamb, goat testis cells; primary lamb, goat kidney cells; and Vero cells culture. Virus title reached 4.4 – 6.4logTCID50 after 7 times passed depending on isolated strains and type of cell.

–  The isolated goat poxvirus can be adapted in chorioallantoic membrane (CAM) of 11-day-old chicken embryos.

–  The isolated goat poxvirus strains were considerably more pathogenic in goats with 100% mortality and morbidity, however, caused only very mild fever and no clinical symptom in sheep.

– The isolated goat poxvirus is high pathogenicity, caused acute and severe disease. When inoculated with 104 TCID50 poxvirus intradermally and intranasally to 3-4 month old goats, the infected goats have the typical symptom and lesions as infected in the field.

– Virus was identified in several tissues such as skin, mucous membrane, blood (fever time), lung, spleen and kidney.

Pham Hung, D.V.M, PhD Do Van Khien