The good news is that increasing numbers of people infected with the HIV are being treated with medicine that keeps them healthier and - at the same time - makes them less likely to spread the virus to others.
But experts at the International AIDS Conference this week in Washington voiced growing worry about the emergence of drug-resistant HIV strains that can evade the medicine.
Worst hit are the United States, Japan, Europe and Australia, where resistance was found in 10% to 17% of patients, mainly because medicines have been in use in richer countries longer than in developing and emerging economies, the World Health Organisation said in a study released.
Resistance could hamper progress
In the poorer regions of the world, the resistance rate has been rising, with about 7% of people under treatment since 2010 showing resistance to HIV drugs, WHO reported.
"Rapid expansion of HIV treatment with antiretrovirals has so far resulted in an increase of observed levels of HIV drug resistance," said WHO AIDS expert Silvia Bertagnolio.
She said the trend could endanger the progress that has been made over the last decades in reducing the number of new infections and deaths worldwide.
Follow resistance patterns
The increase was particularly apparent in Africa, for one of the categories of HIV drugs, the NNRTI class, according to the WHO report. It was "not the high level of drug resistance that many feared," the WHO report said.
A study published in British medical journal the Lancet reflected similar findings. East Africa was deemed to be the region worst affected by a rising prevalence of drug-resistant strains of HIV, with about a 30% resistance rate, according to Ravinda Gupta from the University College in London, one of the study authors.
South Africa had a resistance rate of 14%, the study said.
Resistance to treatment can be arise from patients failing to stick to the strict regimen for taking anti-retroviral drugs. WHO urged countries to closely follow resistance patterns.
For drug-resistant patients, there is a second line of more expensive and stronger medicines.
(Sapa, July 2012)
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