Professor Bryan Fry from UQ's School of the Environment said the study revealed the venoms of three species of mamba were far more neurologically complex than previously thought, explaining why antivenoms were sometimes ineffective.

"The Black Mamba, Western Green Mamba and Jamesons Mamba snakes aren't just using one form of chemical weapon, they're launching a coordinated attack at 2 different points in the nervous system," Professor Fry said.

"If you're bitten by 3 out of 4 mamba species, you will experience flaccid or limp paralysis caused by postsynaptic neurotoxicity.

"Current antivenoms can treat the flaccid paralysis but this study found the venoms of these three species are then able to attack another part of the nervous system causing spastic paralysis by presynaptic toxicity,

"We previously thought the fourth species of mamba, the Eastern Green Mamba, was the only one capable of causing spastic paralysis.

"This finding resolves a long-standing clinical mystery of why some patients bitten by mambas seem to initially improve with antivenom and regain muscle tone and movement only to start having painful, uncontrolled spasms.

"The venom first blocks nerve signals from reaching the muscles but after the antivenom is administered, it then overstimulates the muscles.

"It's like treating one disease and suddenly revealing another."

Mamba (Dendroaspis species) snake bites are a significant threat in sub-Saharan Africa accounting for 30,000 deaths annually.

PhD candidate Lee Jones who conducted the experimental work on the mamba venoms said the research proved new antivenoms were critical to saving lives.

"We set out to understand different venom potencies between mamba species," Mr Jones said.

"We expected to see clear flaccid paralysis inducing post synaptic effects, and effective neutralisation by antivenom.

"What we were not expecting to find was the antivenom unmasking the other half of the venom effects on presynaptic receptors.

"We also found the venom function of the mambas was different depending on their geographic location, particularly within populations of the Black Mamba from Kenya and South Africa.

"This further complicates treatment strategies across regions because the antivenoms are not developed to counteract the intricacies of the different venoms."

Professor Fry said specialised antivenoms could be developed following this study to increase efficacy rates.

"This isn't just an academic curiosity, it's a direct call to clinicians and antivenom manufacturers," Professor Fry said.

"By identifying the limitations of current antivenoms and understanding the full range of venom activity, we can directly inform evidence-based snakebite care.

"This kind of translational venom research can help doctors make better decisions in real time and ultimately saves lives."

The lab work was completed in collaboration with Monash Venom Group.

This research was published in Toxins.

Public health research has identified long commutes, noise, and light pollution from densely populated living environments as factors that impair sleep. While such metropolitan housing offers advantages in commuting time, its livability is far less than the suburbs. To find a balance between convenience and sleep, urban architecture research, which examines the relationship between housing location, size, and sleep health, could help answer the question of "Where and what size home should one have for better sleep?"

Seeking this answer, a research group led by Professor Daisuke Matsushita at Osaka Metropolitan University's Graduate School of Human Life and Ecology investigated whether commuting time and residence predict insomnia and daytime sleepiness among residents of the Tokyo metropolitan area.

Based on an online survey using stratified random sampling, commute time was calculated using a route search system derived from the mode of transportation and postal codes of participants' homes and workplaces. Insomnia and daytime sleepiness were assessed using the Athens Insomnia Scale and the Epworth Sleepiness Scale. The team also examined whether these relationships persist after adjusting for demographic and socioeconomic factors.

Data analysis revealed that even after adjusting for covariates, longer commutes predicted insomnia and daytime sleepiness, while smaller housing size predicted insomnia. Further, a trade-off was observed between commuting time and floor area in cases of insomnia. For housing units meeting the urban-oriented residential area standard of 95 m² for a four-person household, commuting times exceeding 52 minutes reached the insomnia cutoff value.

"Housing choices and supply that consider the trade-off between location and size may help improve the sleep health of commuters and reduce sleep-related economic losses in metropolitan areas," said Professor Matsushita.

The findings were published in the Journal of Transport and Health.

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