By Michael Kahn
LONDON, Sept 24 (Reuters) - The rate of HIV infection among people who inject themselves with drugs appears to be rising, according to a study published on Wednesday.
An estimated 3 million self-injecting drug users worldwide may be HIV positive, said the analysis of peer-reviewed studies and data from United Nations agencies and international experts.
It identified injected drug use in 148 countries and found HIV infections among these kind of users topped 40 percent in nine nations: Estonia, Ukraine, Myanmar (Burma), Indonesia, Thailand, Nepal, Argentina, Brazil and Kenya.
"The new data do suggest increases in both the number of injecting drug users and the prevalence of HIV in users," Kamyar Arasteh and Don Des Jarlais of Beth Israel Medical Centre in New York wrote in a commentary about the study published in the medical journal Lancet.
They said there may be time to educate people in countries where injecting drug use is common but the virus has not yet begun infecting users to a large degree.
Used syringes can spread HIV. Infected drug users are also more likely to engage in risky behaviour such as unprotected sex that can spread the virus that causes AIDS.
The researchers estimated that in 2007 nearly 16 million people around the world injected drugs, with China, the United States and Russia having the largest number of such users.
They also noted there was little data from places in Africa but said Southeast Asia, eastern Europe, and Latin America were areas of worry.
"Injecting drug use occurs in most countries and HIV infection is prevalent among many populations of injecting drug users, representing a major challenge to global health," Bradley Mathers of the National Drug and Alcohol Research Centre in Australia and colleagues wrote.
The review showed big differences worldwide. For example, in Britain 0.4 percent of people aged 15 to 64 injected drugs, with 2.3 percent of them estimated to be HIV positive.
In Spain the proportion of addicts is lower at 0.31 percent but nearly 40 percent of them have HIV, the highest proportion in Europe, the researchers said.
Australia and New Zealand have maintained a very low level of HIV infection even though they have more injected drug users, something the researchers attributed to swift introduction of needle and syringe exchange programs in the 1980s.
They also cited Estonia as a country representative of the quick spread of HIV infections among drug users in recent years.
"A decade ago HIV was not identified among people who inject drugs in Estonia," the researchers said. "A more recent estimate now suggests that the prevalence of HIV infection in some populations has reached 72 percent in one sample of injecting drug users." (Reporting by Michael Kahn; Editing by Maggie Fox and Mark Trevelyan)