A total of 234 sera from healthy Malaysians of diverse ethnic origins were tested for antibody to the Z29 and prototype GS strains of HHV-6. The prevalence in the races ranged from 58 to 80% for the GS strain and 49 to 76% for the Z29 strain. The highest prevalence was in Malays with semi-urban cultural lifestyles and lowest was in the indigenous rural tribes (Ibans, Kadazans, Bidayuhs, and Orang Asli). The antibody titres to GS and Z29 virus capsid antigens differed in 11 (4.7%) samples by more than 2 dilutions. In 9 of the 11 sera the titres to GS strain were higher than to the Z29 strain. The differences in the antibody titres between strains of HHV-6 may reflect subtle changes in antigen structure of the virus recognised by some individuals.
The prevalence of antibody to human herpesvirus type 6 (HHV-6) and Epstein-Barr virus (EBV) viral capsid antigens (VCA) were analysed in sera from Kadazans of Sabah, North Borneo. At a serum dilution of 10, about 34% were positive for HHV-6 antibody but in contrast all 95 individuals studied were positive for EBV VCA antibody. The study shows that HHV-6 and EBV infection occur independently. The low frequency of seropositive individuals in this community suggests that other than socioeconomic factors are responsible for the spread of the virus.
Baicalein is a flavonoid mainly obtained from plants with wide range of biological activities, including neuroprotection. An acute and unexpected chronic stress (UCS) protocol has recently been adapted to zebrafish, a popular vertebrate model in brain research. The present study was aimed to evaluate baicalein's anti-anxiety potential in a zebrafish model by induction, which included neuropharmacological evaluation to determine behavioural parameters in the novel tank diving test (NTDT) and light-dark preference test (LDPT). The toxicity was also assessed using the brine shrimp lethality assay, and the 50% lethal concentration (LC50) was determined. The animals were then stressed for 7 days before being treated with different doses of baicalein (1 and 2 mg/L) for another 7 days in UCS condition. Due to acute stress and UCS, the frequency of entries and time spent in the 1) top region and 2) light area of the novel tank reduced significantly, indicating the existence of elevated anxiety levels. The biological activity of baicalein was demonstrated by its high LC50 values (1,000 μg/ml). Additionally, baicalein administration increased the frequency of entries and duration spent in the light region, indicating a significant decrease in anxiety levels. Overall, the present results showed that baicalein has a therapeutic advantage in reversing the detrimental consequences of UCS and acute stress, making it is a promising lead molecule for new drug design, development, and therapy for stress.