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Improvement of Polio Bulk Production Technology by Cell Culture Application on 10 layer Cellstack

Hoang Trong The, Nguyen Anh Tuyet, Pham Ich Tung, Nguyen Duc Bach, Nguyen Thuy Huong

Received: 01-05-2021 / Accepted: 07-06-2021
Poliomyelitis is an acute viral infectious disease caused by a poliovirus that damages the brainstem, spinal cord, andirreversible motor neuron damage. In Vietnam, the polio vaccine hasbeen produced from thelive attenuated poliovirus strain (the Sabin strain)inoculated on Macaca mulattaprimary monkey kidney cells. Inthe conventional procedure, cells are cultured in a monolayer on Roux bottles with a limited surface, therefore, the yield is insufficient. Thisstudy applied a new approach to improve the production efficiency andhigher yield of Polio vaccineby using 10-layer cellSTACK® instead of using glass Roux bottles. Cultureconditions were optimized with the different cell densities and thevolume of the culture medium. The results showed that the optimal density of cells for culture was 156.000 cells/ml and the optimal volume of medium for cell culture after virus inoculation was 150 ml/layer. The optimalparameterswere applied to validate the trial production of3 continuous batchesby using 20of 10-layer cellSTACK® per batch. The result was consistentforall 3 batcheswith high viral titers from7.73 to 7.76 log10CCID50/0.1ml,higher than the standard 5.5 log10CCID50/0,1ml.
Application of PCR Techniques for Diagnosis of Feline Herpesvirus -1 (FHV-1) in Cats

Nguyen Thi Ngoc, Le Van Phan, Ngo Thi Hanh, Ho Chi Luu, Trinh Thi Bich Ngoc, Nguyen Thi Yen, Le Van Hung

Received: 01-12-2020 / Accepted: 26-04-2021
Feline Herpesvirus 1 (FHV-1), an enveloped double-stranded DNA virus, is one of the major pathogens of feline upper respiratory tract disease (URTD) and ocular disease. This study aimedto applyPCR techniques for diagnosis ofFHV-1. The study was conducted on 317 cats. The results showed that there were 62 out of 317 cats (19.56%)identified with the signs of FHV-1 infected cats by the clinical diagnosis method. Twenty-two out of 62 cats were positive with FHV-1 by PCR method accounting for 35.48%.Twenty-two out of 317 cats were positive with FHV-1 accounting for 6.94%compared with a total of the investigated cats. The Feline Herpesvirus -1 infection rate in cats < 12 months higher than adult cats and FHV-1 infection rate in unvaccinated cats higher than vaccinated cats. The disease was clinically manifested by severe depression, anorexia, ocular discharge, nasal discharge, sneezing, conjunctivitis, keratitis. In addition, some cats have had oral ulceration and fever.Almost all cats with FHV-1 have presented a slight increase of white blood cells (17.77 ± 0.89 103/µl).
Prevalenceof Porcine Cytomegalovirus Causing Inclusion Body Rhinitis in the Pig Farms of Northern Vietnam

Nguyen Thi Hoa, Nguyen Thi Lan, Hoang Thi Phuong, Nguyen Thi Huyen, Nguyen Thi Thu Hang, Truong Quang Lam

Received: 07-03-2020 / Accepted: 13-04-2020
The study was conducted to detect the presence of Porcine Cytomegalovirus (PCMV) in northern Vietnam pig farms.Total122 samples of pigs with respiratory pathological signs were screening by PCR and identified 59 positive samples with PCMV, accounting for 48.36%. Results of analyzing the nucleotide (nt) and amino acid (aa) of 3 PCMV virus strains collected in Thai Binh and Ha Noi showed that these strains were closely related to one other, sharing 99.22-100% at nt and 99.17-100% at aa, respectively. Phylogenetic tree analysis indicated that the PCMV strains belonged to two different branches, PCMV1.HN.2018 and PCMV3.HN.2019 strains were in the same branch as HN0601 strain isolated in China (accession number HQ686081), the 489 strain of Germany (AF268042), the OF-1 strain of Japan (AF268041) and the 55b strain of Spain (AF268040). Meanwhile, the PCMV2.TB.2019 strain was located in the same branch as the FJ01 strain isolated in China (MG696113). Thus, it can be concludedthat PCMV had circulated among pigs raised in northern Vietnam and had the same origin as the PCMV strains from China.
The Preliminary Result on Detection of Waterfowl Parvovirus in Hung Yen Province 2019

Nguyen Van Giap, Dang Huu Anh, Cao Thi Bich Phuong, Nguyen Thi Bich, Nguyen Huu Huan, Huynh Thi My Le

Received: 30-12-2019 / Accepted: 18-01-2020
This study was done in order to confirm the presence of waterfowl parvovirusesin clinical cases of short beak and dwarfism syndrome at Hung Yen province in 2019. The main clinical signs of sick duckswere watery diarrhea, short beak and stunting. Gross lesions werepale ofmyocardium, liver with fibrinous exudate and enlargement of the gallbladder. The combinations of PCR based-detection,sequencing and sequence analyses of the protein-coding genes (NS and VP1)confirmed the presence of waterfowl parvovirus insickducks. The detected waterfowl parvovirus was genetically grouped with novel goose parvovirus (NGPV group).
Epidemiology Characteristics of Canine Distemper Diseases in Dogs in Hanoi

Nguyen Thi Huyen, Pham Ngoc Thach, Nguyen Vu Son, Nguyen Huu Nam

Received: 14-03-2019 / Accepted: 10-06-2019
This study aimedto determine the prevalence of Canine distemper disease in Hanoi as an important information for disease prevention. An epidemiological study on 18244 dogs was conducted in some veterinary clinics in Hanoi from 2013 to 2018. The clinical diagnosiswas based on the specific clinical signs. Treatment and clinical outcome were followed after confirming by CDV Ag test kit.The study found that575 (3,15%) dogswereinfected with Canine distemper virus (CDV) in 14 popular dog breeds with the typiclcal gastrointestinal, respiratory and neurological symptoms. Mong Coc breed hadthe highest positive proportion (6.32%), followed by Becgiebreed (5.56%), Corgi breed (4.28%), Alaska (4.27%). The lowest positive percentage (1.62%) was observed in Rottweiler breed. The infection and successful treatment percentage significantly differred from one year to another (P <0.05). Among age groups, dogsaged 2-6 months old hadthe highest CDV positive rate (60.35%), followed by group of 6-12 months old (15.13%), under 2 months old (12,35%) and lowest in over 12 months old dogs(12.17%). The prevalence of CDV among seasonsof winter, spring and autumn were 39.13%, 35.82% and 11.83%, respectively. The infected CDV dogs also had statistically significant difference in age and season of the year (P <0.05).
Growth Performance and Carcass Yield of Crossbred Pigs Born from Duroc Boars Mated with Duroc×(Landrace×Yorkshire) Sows Survived African Swine Fever

Do Duc Luc, Nguyen Thi Xuan Hong, Ha Xuan Bo, Nguyen Thai Anh, Nguyen Thi Vinh, Pham Kim Dang, Trinh Hong Son

Received: 21-11-2023 / Accepted: 26-01-2024
The study was conducted at a pig farm in Van Lam district, Hung Yen province from August 2021 to November 2022 to evaluate the growth performance and carcass traits of D×(DLY) fattening pigs born from Duroc×(Landrace×Yorkshire) survivor sows infected African swine fever virus and Duroc boars. A total of 110 pigs (61 females and 49 barrows) were recorded from birth to the end of the experiment at 223.36±14.78 (± SD) days of age. Pig was individually tattooed at birth and ear tag at weaning. The body weight of each individual was weighed at birth and weaning. Back fat thickness (BFT), longgissimus muscle depth, loinmuscle area, intramuscular fat (IMF) and lean meat percentage (LMP) were determined by ultrasound on live pigs at the same time of weighing body weight at the end of the experiment. The results showed that the finishing weight (132.40kg), average daily gain (640.55g) in barrows tended to be higher (P = 0.074 and P = 0.057) than those in female pigs (126.60kg and 608.75g). BFT, IMF in barrows were significantly higher than female pigs (P <0.01) but LMP was lower (P <0.001) and were 16.49 and 13.41mm; 2.54 and 2.19%; 57.63 and 61.03% respectively. D×(DLY) can be used as fattening pigs with carcass traits similar to normal pigs but with lower weight gain.
Evaluating Adaptability Potential of Cucumber Hybrids in the Red River Delta Areas

Tran To Tam, Tran Thi Minh Hang, Pham My Linh

Received: 25-02-2020 / Accepted: 17-04-2020
The study aimed at evaluatingthe growth, development, yield and quality of 3 potential cucumber hybrids THL2, THL6 and THL9 in the Red River Delta (Hanoi, Ha Nam and Hung Yen provinces) in fall-winter season 2017. The experiment fields were arranged in randomized complete block design with 3 replications and the control cultivar was GL1-2. The results showed that the growing duration time of these hybrids was approximately the same as the control cultivar in a total average of growing time (85-88 days after planting), vigorous growth, early appearing of female flowers (30-32 days after planting), early harvest (35-38 days after planting) and long harvest period, respectively. Although there was no significant difference among three hybrids and the control, THL9 had the significantly highest individual yield due to attaining more fruit per plant and higher fruit weight. Furthermore, THL9 was not damaged by powdery mildew and downy mildew diseases, infected very lightly by viruses so that these hybrids have been given the highest harvested yield, reached by 48 tons/ha in all three different experiment sites.The study initially indicated that THL9 showed adaptability to the ecological conditions in the Red River Delta.
A Molecular Based Study on The Spatio-Temporal Dynamics of Porcine Circovirus Genotype 2d (PCV2d) Circulating in Vietnam

Pham Hong Quan, Pham Cong Hoat, Huynh Thi My Le

Received: 04-05-2017 / Accepted: 09-06-2017
This study aimed at providing an up-to-date information on the molecular epidemiology of porcine circovirus type 2 (PCV2) circulating in Vietnam with a focus on the spatio-temporal dynamics of a newly defined PCV2d genotype. The results revealed a presence of multiple genotypes/clusters of PCV2, such as 1A/1B, circulating recombinant form (CRF) of PCV2b, and PCV2d. In northern, central and southern Vietnam, a co-circulation of multiple genetic clusters of PCV2 was observed in each sampling location at the same time period. All field strains of PCV2d circulating in Vietnam from 2004- 2017 were predicted to have the most common recent ancestor originated from China, however, they located at different branches of the PCV2d- phylogenetic tree.
Evaluation of Agro-Biological Characteristics of some Cassava (Manihot EsculentaCrantz) Materials in Field Conditions and Screening of the Resistance to CMV in Artificial Infection

Hoang Thi Thuy, Tran Thi Thanh Ha, Vu Thi Bich Hanh, Nguyen Van Ha, Duong Thi Loan, Vu Van Liet

Received: 11-02-2020 / Accepted: 11-08-2020
This study was conducted to evaluate some agro-biological characteristics of 14 domestic and exotic cassava materials in Gia Lam, Hanoi condition, and to evaluate the resistance of the materials through artificial infection experiments by the transplanting method. The material was grown in the field in a sequential experiment without repeating, tracking some agro-biological characteristics. The materials were havested after 8-11 months. The plant height of the materials ranged from 165.2-183.2cm, there are 8 materials with branching height. Most materials have only 1 stem/cluster, CM15, CM21 had 2 stems/cluster and CM60 had 3 stems/cluster. The number of tubers/tree varies from 4.3-15.8 tubers/tree. The highest weight of fresh tubers was obtained CM15 (5.0 kg/tree) and 2 control varieties (5.26-5.82 kg/tree). Using the tranplanting method, evaluated after 2 weeks, 40 successful transplanted trees of 13 materials were evaluated. Genotyping of these transplanted trees was checked by JSP1/JSP2 and JSP1/JSP3 primers detected the presence of ACMV in plants of 8 materials (CM2, CM3, CM8, CM15, CM20, CM60, KM140 and KM94). Assessing the level of infection after 3 months of transplantation, the group of resistant and highly resistant varieties were identified including CM15, CM16, CM21, CM60, CM88, CM50, CM61 and KM94.
African Swine Fever: Current State in Vaccine Research and Action Experience for Effective Control from Other Countries

Nguyen Vu Son, Nguyen Huu Nam, Bui Tran Anh Dao, Bui Thi To Nga, Nguyen Thi Lan, Nguyen Thi Hoa

Received: 18-03-2019 / Accepted: 29-03-2019
African swine fever (ASF) is a contagious viral hemorrhagic fever, that can kill up to 100% of infected pigs. ASF isoriginally occurred inmanyAfrican countries. Currently, the ASF has spread to central and eastern Europeancountries and China. Since its first report on 19 February 2019to 07April 2019,twenty threeprovinces/cities in the North and Middle of Vietnam have been reportedwith ASF incidenceand tend to spread to southern provinces. Although live-attenuated vaccines and subunit vaccines may serve as promising candidates, the vaccine development against ASF has been hampered by large gaps in knowledge of the biology of ASF virusandits interaction with the hosts or immunity. Strict biosecurity remains the most crucial aspect in the control and spread of ASF between domestic pig farms. In this review, important information on dificulties and prospect for developing ASF vaccine as well as effective experience from other countries were evaluated and discussed. Furthermore, the approp[riate recommendations applied toASF situation in domestic pigs in Vietnam were provided.
Population growth of Small Brown Planthopper Laodelphax striatellusFallen (HOMOPTERA: DELPHACIDAE)

Tran Quyet Tam, Tran Dinh Chien, Nguyen Van Dinh

Received: 15-11-2013 / Accepted: 26-12-2013
The Small Brown Planthopper Laodelphax striatellus Fallen (SBPH) is a key insect pest of rice in Northern provinces. In addition to direct damage to development and productivity of rice, SBPH is a vector of viral diseases of rice. The study was conducted at the relative humidity of 85% and two temperatures, 250C and 300C with the food being 15-day old rice seedlings of variety Bacthom No 7. The results showed that at 250C and 300C SBPH’s life cycle was relatively short with 28.5 days and 24 days; the oviposition time with 9 days and 7 days; and average number of eggs per female 154.07 and 104.63, respectively. At 250C and 85% RH, SBPH’s the natural intrinsic rate (r) was relatively high (0.1194); Net reproductive rate (R0) was 52.07 and time for double population (DT) was 5.81 days. At 300C and 85% RH, SBPH’s the natural intrinsic rate (r) was relatively high (0.1294); Net reproductive rate (R0) was 32.91 and time for double population (DT) was 5.36 days.
The Effects of Cell Density, Temperature and pH on Lactoferrin Productionfrom Recombinant Pichia PastorisKM71H-3 Strain

Nguyen Thi Thuy, Trinh Thi Thu Thuy

Received: 18-05-2020 / Accepted: 23-12-2020
Lactoferrin (LF) is a glycoprotein of the transferrin family whose general function is to transport iron. LF is capable of enhancing the immune system, antibacterial, antioxidant, anti-tumor, and antiviral activities. The gene encoding LF derived from bovine has been successfully expressed in recombinant P. pastoris KM71H-3 strain on 2xMMP medium. This study aims at investigating the effects of culture conditions including initial biomass cell density (equivalent to OD600 value from 0.5-2.0), temperature (20°C, 24°C,28°C), and initial pH of the medium (5.5-7.5). The LF expression level was evaluated by SDS – PAGE and Dot bloting methods. The SDS- PAGE andDot - blot results showed that LF was expressed in 2xMMP mediumwell with the optimal conditions were at 28°C, pH 6.0 and the initial biomass cell density (OD600) 0.5.

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