Genital Ulcer Disease - Causes
Sexually transmitted diseases have been described throughout history. Their impact on personal and public health has been significant, as newer pathogens, some with transmission patterns not exclusively via sexual means, have been identified and added to the pantheon of organisms that bedevil our population. Though not reviewed in this chapter, it is essential to consider Human Papillomavirus (HPV), Hepatitis A, B, and C, and the Human Immunodeficiency Virus (HIV) as infections transmitted through sexual contacts. This chapter will focus upon those patients who present with ulcerative genital syndromes, specifically chancroid, genital herpes infection, granuloma inguinale, lymphogranuloma venereum, and syphilis. The approach to the patient with genital symptoms encounters a limited number of pathogens which demonstrate somewhat overlapping clinical scenarios, and may be complicated by the fact that many pathogens are synchronous.
The causative agent of chancroid is Haemophilus ducreyi, but it was not until the late 19th century that this condition was delineated separately from syphilis. Though modestly common throughout the world, chancroid is infrequently encountered in the United States. As a cause of genital ulcer disease, its rank order is third behind herpes simplex virus and syphilis. Chancroid, by virtue of its isolation difficulties as well as the variable reporting requirements from state to state, is clearly underreported and only 30 case notifications were sent to the CDC in 2004. Selected outbreaks in various urban areas in the United States have been linked to prostitution and illegal drug use. HIV co-infection may exist, and clearly transmission of the infection is enhanced by genital ulceration. Uncircumcised men, lower socioeconomic demographics and patronage with prostitutes pose risk factors for this disorder.
The causative agent for genital herpes is the Herpes simplex virus (HSV) of which there are two serotypes: HSV-1 and HSV-2. Both may be pathogenic. HSV-2 is the more common of the two types in genital ulcer disease, although the incidence of primary HSV-1 genital infection may soon approach 50%. Genital herpes is the most common cause of genital ulcer disease in the United States, remains quite prevalent in other North American countries and Europe, but is distinctly uncommon in the developing world. These infections are reported to the CDC as initial visits to physicians for their totals, documenting a steady increase almost annually from 1966 to 2004, as the number of cases has gone from 19,000 to 269,000 in that time frame. Herpes infections are commonly identified amongst most sexually active individuals but have been associated with lower socioeconomic status and men who have sex with men.
The causative agent of granuloma inguinale is Klebsiella granulomatis, a Gram negative bacillus formerly known as Calymmatobacterium granulomatis. It is rather rare to find this infection in the developed world unless travel to an endemic area such as the Indian subcontinent, Papua New Guinea, parts of Brazil, central Australia or central and southern Africa is discovered historically. There remains some debate over the exclusive sexual transmission of this disease process, as some extragenital lesion locations clearly suggest a non-venereal route. Donovanosis is so unusual a finding in the United States that any reported information is uncommon and inconsistent. As in the case of other genital ulcer diseases, HIV transmission is enhanced when ulcerative lesions are present.
The causative agent of lymphogranuloma venereum is Chlamydia trachomatis, serovars L1, L2, and L3. The distribution of this disorder is uncommon in the industrialized world, but may be centered in the tropical areas of developing countries located in Asia, Africa, and South America. Men who have sex with men are the major reservoir for this disease in the United States. There is no national surveillance for lymphogranuloma, although 24 states still report this disease. Only 27 cases were reported to the CDC in 2004. As in the other cases of genital ulcerative diseases, HIV transmission is enhanced in the face of ulcerative lesions.
The causative agent of syphilis is the bacterial spirochete Treponema pallidum. Syphilis has been recognized since the late fifteenth century and has been found all over the world in distribution. The data for syphilis is somewhat difficult to interpret as the information that is reported has combined both primary and secondary stages, thus making an exact evaluation of the number of primary infections open to interpretation. Rates of syphilis have fluctuated greatly over the last 20 years, with an increase seen during the 1980ís, followed by a decline of 90% during the decade 1990-1999. Rates are once again on the upswing in the current decade, and 2004 information revealed 7980 new cases, demonstrating an increase of 11.2% from 2003 totals. Risk factors include HIV disease (both for transmission and reception of syphilis), men who have sex with men, prostitution contacts, lower socioeconomic status, and illicit drug use.