EV71:TLLcho virus murine model of enterovirus A71 neurological disease does not exhibit neurogenic pulmonary oedema.

Small animal models play an important role in investigating and revealing the molecular determinants and mechanisms underlying neuro-virulence of enterovirus A71 (EV-A71). In our previous study, we successfully developed two mouse cell-line replication competent EV-A71 strains (EV71:TLLm and EV71:TLLmv) which were capable of inducing neuro-invasion in BALB/c mice. The more virulent EV71:TLLmv exhibited ability to induce acute encephalomyelitis accompanied by neurogenic pulmonary oedema. EV71:TLLcho virus strain was generated from EV71:TLLm by a series of passages in CHO-K1 cells. EV71:TLLcho demonstrated a broader range of infectivity across various mammalian cell lines and exhibited complete cytopathic effects (CPE) within 48 hours post-inoculation in comparison to EV71:TLLm or EV71:TLLmv. EV71:TLLcho consistently yielded higher levels of viral replication at all time points examined. In comparison to EV71:TLLm, EV71:TLLcho consistently induced more severe disease and increased mortality in one-week old BALB/c mice. However, unlike mice challenged with EV71:TLLmv, none of the mice challenged with EV71:TLLcho progressed to severe acute encephalomyelitis and developed neurogenic pulmonary oedema.

Effect of chemical fogging on immature Aedes mosquitoes in natural field conditions.

INTRODUCTION: Dengue and dengue haemorrhagic fever are common and serious arboviral diseases endemic in a number of countries situated in both the tropical and subtropical belts. METHODS: A prospective study was carried out to examine the environmental factors influencing the ovipositing behaviour of gravid female Aedes mosquitoes in a typical urbanised residential environment in Malaysia. This study reports the effect of the usual ultra-low volume fogging of insecticides carried out by public health officers on the collection of immature Aedes mosquitoes using ovitraps. RESULTS: Throughout the study, no dead immature Aedes mosquitoes was noted in any of the ovitraps set up in all of the fogging and immediate post-fogging periods. The mean number of days of ovitrapping for immediate pre-fogging, fogging and post-fogging periods were 10.3, 10.1 and 10.4 days, respectively. There was no statistically significant difference in the mean duration of ovitrapping cycle among the immediate pre-fogging, fogging and immediate post-fogging periods. The total number of immature Aedes mosquitoes collected in the immediate post-fogging periods was more than the immediate pre-fogging periods, and both were more than the fogging periods. However, there was no statistically significant difference in the total number of immature Aedes mosquitoes collected at various periods. It was not unusual to find dead insects, spiders and even small animals collected in ovitraps or environment in the fogged locality within 48 hours of chemical fogging. CONCLUSION: In this study, the usual chemical fogging in natural environment was ineffective in breaking the reproductive lifecycle by eliminating gravid female Aedes mosquitoes.

A modified mycological medium for isolation and culture of Malassezia furfur.

A mycological medium was developed for primary isolation and culture of lipophilic yeasts. It was initially based on published information of nutrients and trace components that would promote the growth of these yeasts. It was subsequently modified and adjusted to specifically promote the growth of lipophilic yeasts and simultaneously avoid the luxurious growth of other fungi and bacteria. With this medium, the conventional bacteriological procedures such as microbial streaking for pure culture and anti-microbial sensitivity testing could be carried out for these lipophilic yeasts.