(CNN) At least 33 people have tested positive for HIV in northern India after a fake doctor allegedly used a tainted needle while treating them.

Police in Bangarmau in the state of Uttar Pradesh arrested Rajendra Yadav, who allegedly passed himself off as a doctor. He visited his patients on foot or by bicycle at their homes and also provided medication, said Sushil Choudhary, Unnao district chief medical officer.

Yadav used to treat a range of conditions for just a few cents, citing an overburdened health system that is too expensive for most Indians.

Suspicions over malpractice were raised in November when health officials detected an alarming number of patients from the same area testing positive for HIV, the virus that causes AIDS.

"We realized that a lot of cases are coming from just one area," said Choudhary. "We set up a tent, awareness sessions and provided treatment to the patients."

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