Evaluation of the antigen relatedness and efficacy of a single vaccination with different infectious bronchitis virus strains against a challenge with Malaysian variant and QX-like IBV strains

Background@#The predominant infectious bronchitis virus (IBV) strains detected in chickens in Malaysia are the Malaysian variant (MV) and QX-like, which are associated with respiratory distress, nephropathy, and high mortality. On the other hand, the antigenic relatedness and efficacy of IBV vaccines against these 2 field IBV strains are not well characterized. @*Objectives@#This study aimed to determine the antigen relatedness and efficacy of different IB vaccine strains against a challenge with MV and QX-like strains. @*Methods@#The antigen relatedness and the ability of different IB vaccine strains in conferring protection against MV and QX-like were assessed based on the clinical signs, macroscopic lesions, and ciliary activity. @*Results@#The MV strain IBS037A/2014 showed minor antigenic subtype differences with the vaccine virus Mass H120 and 4/91 strains but showed major antigenic subtype differences with the K2 strain. The Malaysian QX-like strain IBS130/2015 showed major antigenic subtype differences with the MV strain IBS037A/2014 and the vaccine strains except for K2. Chickens vaccinated once with Mass (H120) or with non-Mass (4/91 and K2) developed antibody responses with the highest antibody titer detected in the groups vaccinated with H120 and 4/91. The mean ciliary activities of the vaccinated chickens were between 56 to 59% and 48 to 52% in chickens challenged with IBS037A/2014 and IBS130/2015, respectively. The vaccinated and challenged birds showed mild to severe lesions in the lungs and kidneys. @*Conclusions@#Despite the minor antigenic subtype differences, a single inoculation with Mass or non-Mass vaccines could not protect against the MV IBS037A/2014 and QX-like IBS130/2015.

Accelerating Chrysomya Megacephala Maggot Growth for Forensic Entomology Cases / Jurnal Sains Kesihatan Malaysia

Forensic entomology is defined as knowledge about insect and its relationship with a decomposed human body. With this knowledge, post-mortem interval (PMI) can be estimated. PMI can be determined by taking into consideration the insect species and the developmental stage of the insects. Identification of the insect species requires the insect to develop into adulthood. Since this will take a relatively long time, the objectives of this study were to optimize temperature and humidity for the growth of Chrysomya megacephala larvae to adults. C. megacephala larvae were transferred into a rearing container and put inside a special incubator with temperature adjusted to 27, 30, 33, 36 and 39°C separately. Once optimum temperature for larvae growth was determined, optimum relative humidity was determined then for the length of time taken for C. megacephala larvae to develop into adults. To achieve this, the larvae of C. megacephala were incubated in a special incubator and the relative humidity set at 54.2, 57.6, 76.0 and 67.5% (control) separately. The developmental stages of C. megacephala for both temperatures and humidity levels were recorded accordingly. Results obtained indicated that C. megacephala developmental stages grew much faster in 33oC than other temperatures. The optimum relative humidity level for the species was 76.0%. By utilizing the appropriate temperature and relative humidity the development of C. megacephala, from eggs to adults could be reduced from 8 to 9 days to 5 days.