Prevalence of Marek’s disease virus in unvaccinated healthy backyard chickens in Cantho city, Vietnam and genetic characterization of meq gene

An investigation was carried out to survey the prevalence of Marek’s disease virus serotype 1 (MDV-1) on unvaccinated healthy backyard chicken flocks from four districts in Cantho city and to analyze the genetic characterization of the meq gene. A total of 353 feather follicle samples were collected from 50 unvaccinated chicken flocks for Marek’s disease to investigate prevalent MDV-1 by polymerase chain reaction (PCR). The four represent strains were chosen for meq gene sequencing. The results revealed that 26 out of 353 samples were positive for MDV-1 accounting for 7.37%. There were significant differences in the prevalence of MDV-1 on chickens among districts (P<0.05). The Meq protein of the four strains (VT, CD, PD, and TL) contained 20.14% proline and three regions of proline repeats. Besides, all four strains occurred with amino acid point mutations. These strains had only a substitution of proline at position 217 as well as interruption of consecutive proline at site 2. Phylogenetic analysis indicated that these strains were within a group relating to virulent Italian isolates

Prevalence of antibiotic resistance genes and genetic relationship of Escherichia coli serotype O45, O113, O121, and O157 isolated from cattle in the Mekong Delta, Vietnam

A total of 39 Escherichia coli strains serotype O45, O113, O121, and O157 isolated from cattle in the Mekong Delta were examined the antimicrobial susceptibility to 13 antibiotics by the disc-diffusion method. Those strains were also analyzed for the presence of antibiotic resistance genes by PCR assay, and their genetic relationship by ERIC-PCR assay. The results of antimicrobial susceptibility testing showed that those strains were sensitive to most of the examined antibiotics, but were relatively high resistance to ampicillin (64.10%), and colistin (53.85%). Those E. coli strains could be resistant against one to eight antibiotics with 22 resistance patterns obtained. Moreover, those E. coli strains harbored one to seven antibiotic resistance genes. Gene tetA (51.28%) and blaampC (48.72%) were detected frequently while gene tetB, blaCMY, and cat1 were not found in those E. coli strains. A total of 21 combined patterns of antibiotic resistance genes were recorded, and the most frequent combined pattern was blaampC+tetA (12.82%). ERIC-PCR analysis revealed that each E. coli serotype exhibited various genetic patterns with 40%-100% of similarity. The most elevated number of patterns were in E. coli O157 (nine patterns), followed by E. coli O121 (six patterns). The prevalence of antibiotic resistance genes and diverse genetic characteristics in those E. coli strains originated from cattle constitute potential risks to local health in the Mekong Delta

Respiratory virus laboratory pandemic planning an surveillance in central Viet Nam, 2008-2010

Introduction: Laboratory capacity is needed in central Viet Nam to provide early warning to public health authorities of respiratory outbreaks of importance to human health, for example the outbreak of influenza A(H1N1) pandemic in 2009. Polymerase chain reaction (PCR) procedures established as part of a capacity-building process were used to conduct prospective respiratory surveillance in a region where few previous studies have been undertaken.Methods: Between October 2008 and September 2010, nose and throat swabs from adults and children (approximately 20 per week) presenting with an acute respiratory illness to the Ninh Hoa General Hospital were collected. Same-day PCR testing and result reporting for 13 respiratory viruses were carried out by locally trained scientists.Results: Of 2144 surveillance samples tested, 1235 (57.6%) were positive for at least one virus. The most common were influenza A strains (17.9%), with pandemic influenza A(H1N1) 2009 and seasonal H3N2 strain accounting for 52% and 43% of these, respectively. Other virus detections included: rhinovirus (12.4%), enterovirus (8.9%), influenza B (8.3%), adenovirus (5.3%), parainfluenza (4.7%), respiratory syncytial virus (RSV) (3.9%), human coronavirus (3.0%) and human metapneumovirus (0.3%). The detection rate was greatest in the 0–5 year age group. Viral co-infections were identified in 148 (6.9%) cases.Discussion: The outbreak in 2009 of the influenza A(H1N1) pandemic strain provided a practical test of the laboratory’s pandemic plan. This study shows that the availability of appropriate equipment and molecular-based testing can contribute to important individual and public health outcomes in geographical locations susceptible to emerging infections