A 22-year-old Brazilian woman was infected with HIV after sharing manicure tools with her cousin, in a rare case of disease transmission, reported Counsel & Heal.

The case is described in a report published in the online journal AIDS Research and Human Retroviruses. The infection was discovered when the woman volunteered for blood donation and tested HIV positive. Blood work showed her condition was normal, but that she had a high viral load, indicating that she had a long-standing infection.

The woman denied all classical transmission routes, including intercourse and needle sharing, and her mother also tested negative. The women both reported sharing manicure equipment with a cousin 10 years ago. At the time, the cousin was unaware of her infection status but later tested positive for HIV.

After analyzing samples from the woman and her cousin, researchers found that the viral genetic material in both women was highly related, indicating the possibility that HIV was transmitted by the manicure instruments.

Manicure utensils are not part of the Centers for Disease Control and Prevention's list of mechanisms by which HIV spreads.

"HIV is not transmitted by casual contact, such as sharing eating utensils, or drinking from the same water glass. This transmission of HIV by shared manicure equipment is a very rare event that should serve not to make people fear HIV or contact with HIV-infected people,” study authors said in a press release.

Study authors noted that the case should make people aware that sharing utensils with possible blood-to-blood contact— such as needles used for drugs, tattoos or acupuncture— can result in transmission of viruses such as hepatitis C and HIV, and that other common viruses can be spread by sharing improperly disinfected equipment.