A man practising as a doctor faces charges of murder and other crimes after over 100 people in a Cambodian village tested positive for HIV.

Yem Chhrin is accused of using dirty needles which transmitted the disease to Roka villagers. Chhrin does not have a license to practise medicine and has not received formal medical training.

The 53-year-old was charged with murder carried out with cruelty, intentionally spreading HIV, and unlawfully practising medicine, according to Battambang provincial court prosecutor Nuon San.

When Chhrin was arrested last weekend, he told police that he did not intend to spread the disease.

"He told us that he had no intention of spreading HIV to villagers," senior provincial police officer Seng Loch told Reuters. "He doesn't know who among his patients was infected with HIV."

Chhrin said he changed his syringes frequently, but did use the same syringe on more than one patient. If someone is HIV-positive, the infected blood can stay on the needle or spread to the solution inside the needle. If a HIV-negative person uses that same needle, the virus can be injected into their bloodstream.

It is unclear what type of medical treatments Chhrin was providing, although his infected patients ranged in age from three to 82 years old. Buddhist monks were among those infected by Chhrin.

Experts from the US and UN have come to Battambang "to determine the source, extent and chain of transmission of HIV infection," the Health Ministry explained. Over 800 villagers were tested, and 106 were found to be HIV-positive.

In 1998, Cambodia had an HIV prevalence of two per cent, which is on the higher end of the spectrum. The country's HIV prevalence was brought down to an estimated 0.7 per cent this year after an aggressive safe-sex campaign. The global HIV prevalence in adults in 2013 was 0.8 per cent, according to the World Health Organisation.