Increase in death toll is seen among intravenous drug users after Russia's annexation of Crimea, due to lack of access to vital therapy, specialists said at the world AIDS forum on Thursday.
Michel Kazatchkine, former head of the Global Fund to Fight AIDS, TB and Malaria, and now the UN's AIDS envoy for eastern Europe, told AFP he was "very concerned" and had heard of "20 documented deaths, possibly more."
Under Ukrainian rule, Crimea provided intravenous drug users with access to methadone, a safer substitute for heroin, and to buprenorphine, a drug used to ease dependence.
Endorsed by the World Health Organisation (WHO), this opioid substitution therapy (OST) helps to wean addicts off heroin and to halt the spread of HIV through prostitution and shared syringes, according to campaigners.
But the annexation of Crimea in March means that Russian legislation, which outlaws these drugs, now prevails in the peninsula.
Pavlo Skala, with the International HIV/AIDS Alliance in Ukraine, said that before annexation, 806 people had enrolled in OST programmes in Crimea.
More than 200 of them were infected with human immunodeficiency virus (HIV), and of these 80 percent were co-infected with hepatitis C.
"Vital (substitution) treatment has been totally cancelled," he said.
"In Ukraine, we hosted 60 of these patients who were able to flee. There were many obstacles for them to come, and they are continuing treatment. Most of these 60 patients came in very poor condition, but now they are stable.
"The other patients in Crimea have all returned to illegal drug use, such as krokodil, a street drug which is exceptionally dangerous," said Skala.
"According to our information, at least 20 people have already died there from various reasons, such as chronic disease, overdose, suicide, but no-one will provide us with actual death certificates," he said in an interview.
For those who stayed behind in Crimea and had HIV, some of the anti-retroviral drugs that they had used were no longer available under Russian control, and they were forced to turn to a Russian-made version, which carried more side effects, he said.
"Because drug use is fuelling the epidemic, there might be a real increase in HIV cases (in Crimea), but it will be hidden and kept undercover by the Russian authorities," Skala warned.
- Russian epidemic -
Under Ukraine's governance, Crimea also made wide use of needle-exchange programmes and provided counselling and support for sex workers and gays, which are also important niche groups for the spread of HIV.
But these services, which covered 14,000 people before annexation, are of limited availability in Russia, if at all, according to HIV specialists in eastern Europe.
Russia has one of the fastest-growing tallies for HIV infections in the world.
Experts say the spread is being driven by intravenous drug use, but is now entering the mainstream community.
According to UNAIDS, the Russian Federation had 170,000 people who were infected with HIV in 2004, a figure that rose to 1.2 million last year.
Russia accounts for over 55 percent of all new HIV infections reported in the European region, according to the European Centre for Disease Prevention and Control (ECDC).