Veterinary Research Forum

Abstract Infectious bronchitis virus (IBV) is an important pathogen in the poultry industry causing avian infectious bronchitis that is, an acute but highly contagious disease affecting the upper respiratory tract, kidneys and reproductive tract. The 3rd passage of a polymerase chain reaction confirmed nephropathogenic IBV isolate was used for this study. Heat stability for 5, 10, 15, 20, and 30 min at 56.00 ˚C, pH sensitivity at pH 3.00, 7.00, 9.00, and 11.00 ultraviolet (UV) irradiation for 10, 15, 20, and 30 min, and chloroform sensitivity were studied. The IBV isolate was found to be susceptible to a temperature of 56.00 ˚C for 5 min and above, UV irradiation within 10 min, chloroform treatment and to pH 11.00 while being resistant to pH 3.00 and 9.00. The second part of the study investigated in vitro effectiveness of the disinfection potential of several commercially used disinfectants in Pakistan against the IBV isolate. For this purpose, Virkon S, Bromosept, and Beloran were employed for the virus inactivation test. Following the IBV challenge for contact time of 1, 5, 10, and 30 min, we counted the number of embryos that died after incubation. Results showed that suitable dilution of disinfectant for the recommended contact period could kill the virus. The maximum susceptibility was seen in the case of Virkon S which killed the virus in just 1 min. Thus, IBV could be killed using commercially available Virkon S, Beloran, and Bromosept after being used in recommended concentrations for recommended contact time.

Abstract Foot-and-mouth disease virus (FMDV) is a highly transmissible pathogen causing severe economic losses in the global livestock sector. Frequent outbreaks of FMDV type-O in Pakistan highlight the need for continuous genomic and antigenic surveillance to track its evolution. This study aimed to isolate and molecularly characterize FMDV type-O from an outbreak in the Punjab province of Pakistan using in vitro cell culture techniques. Samples were processed for viral isolation on a susceptible cell line, followed by RNA extraction. The VP1 gene, pivotal for antigenicity and immunogenicity, was amplified using a one-step polymerase chain reaction protocol. Purified amplicons underwent sequencing, and the nucleotide sequences were translated into amino acid sequences for further analysis. Protein three-dimensional modeling and in silico comparison were performed against the vaccinal seed strain PanAsia-2. The VP1 sequence analysis revealed notable genetic variability among the isolates, indicating adaptive evolution. Structural and antigenic modeling uncovered key differences between the field isolates and vaccinal strain, suggesting potential antigenic drift, which could undermine vaccine performance. The study underscores the dynamic evolution of FMDV type-O in Pakistan and the critical importance of ongoing genomic monitoring to refine vaccine strategies and enhance outbreak control.

Abstract Avian Salmonellosis impacts the economy and public health, with chicken products being a major cause of gastroenteritis. Hygiene, immunization and medicines are all used as control techniques. Bacteriophages provide a safe, targeted alternative. In the present study in vitro evaluation of bacteriophages were done against Salmonella typhimurium. Lytic effect of bacteriophages isolated from poultry sludge was checked on culture of S. typhimurium. Stability study was checked at range of temperature and pH. The phages were stable at temperature (30.00 - 50.00 ˚C) and pH (5.00 - 9.00) where best activity was seen at 37.00 ˚C and pH 7.00. In vitro lytic activity was done at (optical density 600 nm) after exposure to bacterial host at different intervals. Multiplicity of Infection of 1.00 was used to check lytic activity of phages which indicated phages were potent enough to infect bacterial cells within their growth cycle. The percentage of unadsorbed phages was determined by bar chart analysis. The genome of three phages was treated with DNase I where they all were sensitive. Later the nucleic acid of phages was digested by restriction endonucleases (EcoRI and HindIII) both of the enzymes produced various restriction sites with different band. The present study proved that the application of bacteriophages in vitro into bacterial system i.e., S. typhimurium was an attractive method in diminishing infection in commercial poultry thus providing exceptional results that could be used on a large scale.

Abstract Foot-and-mouth disease virus (FMDV) cripples livestock by imparting devastating effects to economy. A good vaccine is the key to stopping it, but due to instability of 146S of FMDV, it is becoming difficult. This is bad because only 146S can fight against disease and its dissociation ultimately leads to decreased potency of vaccine. This study aimed to preserve the integrity of 146S in vaccine using different inactivators and preservatives. Foot-and-mouth Disease virus type ‘O’ was propagated on baby hamster kidney 21 cell lines and inactivated using formalin or binary ethylenimine (BEI). Size exclusion high performance liquid chromatography analysis revealed minimal 146S loss after double inactivation with formalin and BEI. This inactivated virus was further formulated into oil-based vaccine with sodium thiomersal or chloroform as a preservative. Our findings demonstrated that chloroform outperformed thiomersal in maintaining shelf life of vaccine. This claims that the combined approach of double inactivation with formalin and BEI followed by chloroform as preservative offered a promising strategy for developing efficacious FMDV.