Bangladesh moves from being a low-prevalence nation for HIV to one with a concentrated epidemic in injecting drug users.

Bangladesh has been conducting annual serological surveillance for HIV and syphilis since 1998 among most at-risk populations including sex workers, males having sex with males, injecting drug users (IDUs) and heroin smokers. During the seventh round conducted between January and June 2006, 10,368 people were sampled and the overall HIV prevalence was 0.9%. The highest HIV rate was recorded in male IDUs from the capital city Dhaka (7%), and the rates have risen significantly over the rounds (P < 0.001). In Dhaka, most of the HIV-positive IDUs (10.5%) were localized in one neighbourhood, while in the remaining neighbourhoods 1% were positive (P < 0.001). In all other groups, HIV prevalence was <1%. Active syphilis rates were highest in female IDUs (9.9%) followed by female street-based sex workers (8.6%). However, rates in female sex workers in Dhaka declined significantly over the years (P < 0.001). Bangladesh has to act urgently to prevent escalation of the epidemic.