Candidiasis is a fungal condition, also known as thrush or candidosis. The most common cause is a very common yeast called Candida albicans, although candidiasis can also be caused by related fungi such as C. krusei, C. tropicalis and Torulopsis glabrata.1,2

These fungi are very common, but do not normally cause health problems because a fully functioning immune system can keep them suppressed. In people whose immune system is damaged, however, Candida can overgrow and cause symptoms. It can also flourish if the immune system is suppressed for other reasons, such as stress, other viral infections or conditions such as diabetes, or if other normal micro-organisms that live in the body are killed by a course of antibiotics.

There is some evidence that HIV may also play a direct role in candidiasis. Recent research has linked oral candidiasis in HIV-infected people to high viral load, regardless of CD4 count.

Very preliminary research using HIV-positive couples has suggested that in some cases, Candida strains can be transmitted from one person to another. As some strains can be resistant to anti-fungal treatment, this raises the possibility that drug-resistant strains could be passed on to people who have never received anti-fungal treatment themselves.


  1. Bessarab TP et al. Candidiasis of nasal cavity and of paranasal sinuses in HIV-infection. The experience of observation in Moscow City AIDS Center. 15th International AIDS Conference, Bangkok, abstract MoPeB3215, 2004
  2. Melo NR et al. Oral Candida flora from Brazilian human immunodeficiency virus-infected patients in the highly active antiretroviral therapy era. Mem Inst Oswaldo Cruz 99: 425-431, 2004