Map shows areas at risk from bat viruses

South-east Asia, West Africa and sub-Saharan Africa are most at risk from bat viruses "spilling over" into humans, resulting in new emerging diseases, according to a new map compiled by scientists at University College London (UCL), the Zoological Society of London (ZSL) and the University of Edinburgh.

The map shows risk levels due to a variety of factors, including large numbers of different bat viruses found locally, increasing population pressure, and the hunting of bats for bushmeat.

About 60 to 75 per cent of reported human emerging infectious diseases are zoonotic, where infectious diseases in animals are naturally transmitted to humans. The researchers studied bats in particular as they are known to carry multiple zoonotic viruses and are the suspected source of rabies, Ebola and Sars (severe acute respiratory syndrome).

The research, using data published between 1900 and 2013, identified West Africa as the highest-risk hot spot for zoonotic bat viruses. It has also experienced the largest-scale outbreak of Ebola to date.

The study developed risk maps by identifying different factors which are important for driving the early stage of zoonosis.

Sprouty2 gene worsens colorectal cancer

A gene known to suppress the growth and spread of breast, prostate and liver cancers has the opposite effect in some forms of colorectal cancer, University of Missouri School of Medicine researchers have found.

Using different molecular methods, the researchers found that the gene functions differently in colorectal cancer than in other types of cancers.

Sprouty2 is known to block molecular circuits to prevent cancer cells from growing and spreading to other parts of the body. However, the researchers found that in colorectal cancer, Sprouty2 may increase the metastatic ability of cancer cells instead of suppressing it.

The University of Missouri-Columbia said Associate Professor Sharad Khare from the Division of Gastroenterology and Hepatology, who led the study, believes this occurs when the gene is up-regulated, or supercharged.

Colorectal cancer is the most common cancer in Singapore, affecting about 1,000 people a year, and the third most common in the world, affecting 1.2 million people. Cancer deaths attributed to colorectal cancer are mainly due to tumour recurrence and metastasis to other organs.

How fast is a chameleon's tongue?

Chameleons may be slow-footed, but they are known for sticking their tongues out at the world fast and far. Now, for the first time, the true extent of this capability was tested.

The result: a ballistic tongue projection with a peak acceleration 264 times greater than the acceleration due to gravity. In Scientific Reports, Brown University biologist Christopher Anderson shows that in automotive terms, the tongue could go from zero to 96kmh in a hundredth of a second.

Brown University said Dr Anderson's review of the biomechanics literature suggests that the motion has the highest acceleration and power output produced per kg of muscle mass by any reptile, bird or mammal and is the second most powerful among any kind of vertebrate. It is outdone only by a salamander.

Chameleons pre-load most of the motion's total energy into elastic tissues in their tongue. From a study of 20 chameleon species, Dr Anderson noted that the smaller the chameleon, the higher the peak acceleration, relative power and distance of tongue extension relative to body size.

Compiled by Samantha Boh