Two of the four known groups of human AIDS viruses (HIV-1 groups O and P) originated in western lowland gorillas, according researchers who conducted a comprehensive survey of simian immunodeficiency virus (SIV) infection in African gorillas.

HIV-1, the virus that causes AIDS, has jumped species to infect humans on at least four separate occasions, generating four HIV-1 lineages -- groups M, N, O, and P. Previous research from this team found that groups M and N originated in geographically distinct chimpanzee communities in southern Cameroon, but the origins of groups O and P remained uncertain.

If you ask doctors what the biggest myth about the flu is, they will tell you that it's people thinking they have the flu. Flu-like illness can be caused by many pathogens, and most people don't go to the doctor for it, making it difficult to assess how often people really have.  

Older and young people are more susceptible but adults over the age of 30 only catch flu about twice a decade, according to a new paper.  The immune system responds to flu viruses by producing antibodies that specifically target proteins on the virus surface. These proteins can change as the virus evolves, but we keep antibodies in the blood that have a memory for strains we've encountered before.

Scientists have discovered a new hormone that fights the weight gain caused by a high-fat Western diet and normalizes the metabolism - effects commonly associated with exercising.

Hormones are molecules that act as the body's signals, triggering various physiological responses. The newly discovered hormone, dubbed "MOTS-c," primarily targets muscle tissue, where it restores insulin sensitivity, counteracting diet-induced and age-dependent insulin resistance.

There are lots of good reasons not to smoke marijuana and you probably heard or read them all growing up - what you may not have heard is that marijuana, like other pollen-bearing plants, is an allergen which can cause allergic responses.

A new article summarizes research on the ways in which cannabis can act as an allergen. The article draws attention to allergic responses that may be unfamiliar to marijuana users.

Picking cultural winners in the name of public interest is a time-honored tool of government and the social engineers giving them input, but the reasons for bans are often suspect. Banning cigarettes in bars and restaurants rather than creating an evidence-based ventilation requirement was going to cut smoking, it was said, but that hasn't happened no matter what sociological Laffer curve was invoked.

Pundits wanted to create a ghetto-ized underclass but now smokers happily step outside at bars and restaurants, and they meet new people and create their own sub-culture. Less freedom and a more authoritarian government has not caused people to smoke less behind their own closed doors or quit altogether, finds a paper in Nicotine&Tobacco Research.

Gastric bypass and similar stomach-shrinking surgeries are a popular option for obese patients looking to lose weight and they have even been linked to a decreased risk in many types of cancers - except colon cancer. A 2013 long-term study of 77,000 obese patients found that colon cancer rates were higher but a new study in mice could explain the association - and raise safety concerns for a new generation of weight-loss drugs.