Candida Infection as a Risk Factor for HIV Transmission

William B. Kannel, MD, MPH, Barbara S. Levine, PhD, CRNP, CS

Disclosures
In This Article

Abstract and Introduction

Background: Numerous epidemiological studies have documented that ulcerative sexually transmitted diseases (STDs), such as syphilis, chancroid, and genital herpes, promote heterosexual human immunodeficiency virus (HIV) transmission. However, the role of vaginal inflammations, such as Candida infection, in HIV acquisition has not been well established, even though, like Trichomona vaginalis infection, it is rapidly emerging as a significant cofactor in HIV transmission.
Methods: This study was conducted among a high-risk population of heterosexual women, cohabitating with their HIV-positive male partners, to determine if an association exists between vaginal infections, primarily Candida, and HIV seroconversion. These serodiscordant couples (i.e., one of the persons is HIV positive, and the other is HIV negative) are currently enrolled in an ongoing longitudinal heterosexual discordant couple cohort that is being prospectively followed at Project Sans Francisco (PSF), an HIV Prevention and Research Center in Lusaka, Zambia. A nested case-control study that used retrospective laboratory analyses data obtained from medical, clinical, and laboratory records at PSF was employed.
Results: The findings from this study clearly document that women who seroconverted from HIV-negative status during baseline to HIV-positive status at follow-up were significantly more likely to have vaginal Candida infections than were the correspondingly matched seronegative control women.
Conclusions: These findings suggest that high-risk heterosexual HIV-negative women could benefit from appropriate gynecological management and care regarding the prevention and treatment of vaginal Candida infections, especially in resource-poor environments.

A variety of epidemiological studies has documented that ulcerative sexually transmitted diseases (STDs), such as syphilis, chancroid, and genital herpes, increase the heterosexual transmission of human immunodeficiency virus (HIV) infections, including acquired immunodeficiency syndrome (AIDS), in women by creating susceptible portals for viral entry through genital lesions or chancres.[1,2,3,4] Although studies on the role of vaginal inflammations, such as Candida infections, in HIV acquisition remain scarce,[5,6] there is compelling evidence that even nonulcerative vaginal inflammations (e.g., Candida vaginitis, Trichomonas vaginalis infection, bacterial vaginosis, and Chlamydia trachomatis infection) are emerging as risk factors for amplifying HIV transmission when present in HIV-negative women.[7,8,9,10,11,12]

Considerable information about the prevalence of Candida vaginitis among HIV-positive women has been documented over the last decade, but significant gaps remain, particularly with regard to the pathophysiology of clinical infections.[13] Data were collected from nearly 600 women utilizing STD services in South Africa and analyzed to determine whether an association exists between HIV infections and vaginal inflammations. Based on the findings from these women, the authors concluded that normal vaginal flora altered by T. vaginalis infection may account for previous observations that Candida vaginitis promotes HIV transmission.[14] Despite the role of cell-mediated immunity and T cells, there is also controversy about whether immunosuppression by HIV infection enhances susceptibility to vaginal Candida infections.[15] Although various clinical and pathophysiological theories have been postulated, vaginal Candida infection rates among HIV-positive women remain largely undetermined[16] and relatively inconclusive possibly because of study limitations and inconsistency in diagnostic criteria.[17] Moreover, the association between vaginal Candida infections and HIV transmission among heterosexual women in a serodiscordant relationship has not been well defined.

Despite the wealth of information on HIV/STDs, the number of new infections continues to rise rapidly throughout the world, especially in developing countries. Over two thirds of the world's HIV-infected population resides in Sub-Saharan Africa,[18] where heterosexual transmission is considered the primary mode of HIV transmission. In Zambia, for example, the virus infects about one in every five adults, and in urban areas, such as Lusaka, the prevalence rate is upward of 30%.[19] Additionally, it has been shown that in Lusaka, a majority of the HIV/AIDS infections occur through heterosexual transmission among cohabitating adults.[20] Therefore, this study was specifically designed to determine if an association exists between vaginal Candida infection and HIV seroconversion. To address this research question, we used secondary data obtained from a high-risk population of heterosexual women cohabitating with HIV-positive male partners. Specifically, this study examined medical records for microbiological diagnoses of vaginal infections (i.e., Candida, Trichomonas, and gonorrhea) and serological diagnoses for syphilis and the corresponding HIV seroconversion rates among a convenient sample of women enrolled in a large cohort of HIV-discordant couples (i.e., one partner is HIV positive, and the other partner is HIV negative). The women were followed prospectively in a blinded longitudinal observational study at Project Sans Francisco (PSF), an HIV Prevention and Research Center in Lusaka, Zambia.

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