Communicable Disease

Communicable Disease

Introduction

Diseases that affect both men and women and are generally transmitted during sexual intercourse. STDs cause individuals considerable stress because of physical discomforts, psychological pain, possible infertility, and the potential that they may be life-threatening, as in the case of AIDS. STDs cause psychological distress for many reasons, including a need to communicate the problem to one's partner and a need to disclose information about past sexual activities and partners. The term safe sex relates to sexual practices that aid in the prevention of STDs as well as AIDS.

Individuals who are widowed or divorced and who begin dating and seeking new partners after their loss, as well as never-married individuals, are concerned about STDs. Fear of acquiring STDs has led many formerly sexually active people to seek fewer sexual partners. Such concerns have also increased the use of condoms, which, when appropriately used, are thought to reduce the likelihood of spreading most STDs (as well as AIDS).

While young people are more at risk of acquiring an STD, concerns about their transmission are also prevalent among individuals who are divorced or widowed and who seek new partners after their loss, as well as never-married individuals. Fears of acquiring an STD have led many formerly sexually active people to seek fewer sexual partners. These concerns have also increased the use of condoms, as they are thought to reduce the likelihood of spreading most STDs as well as AIDS (Santelli and Brener, 2000).

HIV transmission

Genital ulcer diseases in general and chancroid in particular, have been shown to be significant risk factors in the heterosexual transmission of HIV. Several mechanisms may explain this enhanced transmission. HIV has been detected in chancroid ulcers, and tissue destruction in the lesions may increase shedding of the virus. The disrupted skin barrier may also increase susceptibility to HIV infection. In addition, a higher proportion of HIV-susceptible cells present in chancroid lesions may facilitate HIV transmission. Both CD4+ T cells and macrophages recruited to the site of H. ducreyi infection can harbor HIV in infected individuals. Their location near the point of HIV entry or exit in a chancroid lesion may influence the spread of the virus (Gallet, 2002).

Immunity

The patterns of cellular and cytokine responses that occur during chancroid contrast with those that commonly result in strong antibody responses to infection. Despite observations that individuals with chancroid have higher serum antibody levels to some H. ducreyi surface components than do uninfected controls, recurrent infections are a hallmark of this disease. In fact, Augusto Ducrey, for whom the organism was named, showed in the late 1800s that infection could recur at least 15 times in the same individual. Thus, little or no immunity develops in naturally acquired infection.

Potential virulence factors

Hemoglobin receptor

Iron is needed by all bacteria, and free iron inside the human host is scarce. When grown under iron-limiting conditions in the laboratory, H. ducreyi synthesizes several proteins that are not produced under iron-sufficient conditions. One of these new proteins is an outer membrane receptor that binds hemoglobin, which may ...