and perhaps to gonorrhea. Very young sexually active women and oral contraceptive users with ectopy are particularly susceptible to chlamydial infection. Early average onset of intercourse among females or high rates of oral contraceptive use probably foster rapid transmission of chlamydial infection.

Variations in infectious virulence of Neisseria gonorrhoeae may influence efficiency of transmission of gonorrhea. Certain strains of N. gonorrhoeae are resistant to fecal acids, and are more prevalent among homosexual men, probably because of more efficient transmission by rectal intercourse (38). Other strains that tend to cause disseminated gonococcal infection, with bacteremia and tenosynovitis, are highly susceptible to fecal acids, and uncommon in gay men, perhaps explaining why disseminated gonococcal infection has been relatively uncommon among gay men.

Having considered the three direct determinants of the rate of spread of bacterial STD, we next consider underlying ecologic factors that have influenced the emergence of bacterial STD.

As the economy evolved from hunting to agriculture to industry, patterns of sexual behavior, reproduction, moral codes, and religion presumably adapted. With the transition from hunting to agriculture, children became economic assets at an early age, the family became the unit of production, and land became a valuable commodity to be passed on from father to son. Early marriage, monogamy, and multiple births were reinforced by religion and moral codes (39). In sociobiological terms "greater predictability of food in space and time promotes the evolution of territoriality. When the resources are dense and easily defensible, and when food is the limiting resource, the optimum strategy is the double defense—by means of the monogamous pair bond" (40).

With the industrial revolution in Europe and North America, the family unit fragmented, as parents and children left the home and village to find work in cities, children no longer were economic assets, marriage was delayed, secular institutions began to replace religious and moral codes, and premarital and extramarital sex became more common. This scenario is replayed conspicuously today in the emerging countries throughout Asia, Latin America, and Africa.

Front Matter (R1-R12)

Lyme Disease: A Growing Threat to Urban Populations (1-14)

Working Parents: The Impact of Day Care and Breast-Feeding on Cytomegalovirus Infections in Offspring (15-30)

Changes in Human Ecology and Behavior in Relation to the Emergence of Diarrheal Diseases, Including Cholera (31-42)

Dengue: The Risk to Developed and Developing Countries (43-58)

Hepatitis Viruses: Changing Patterns of Human Disease (59-76)

Population Migration and the Spread of Types 1 and 2 Human Immunodeficiency Viruses (77-98)

Impact of Malaria on Genetic Polymorphism and Genetic Diseases in Africans and African Americans (99-112)

Hospital-Acquired Infections: Diseases with Increasingly Limited Therapies (113-134)

Evolution of Drug-Resistant Tuberculosis: A Tale of Two Species (135-140)

Effect of Human Ecology and Behavior on Patterns of Sexually Transmitted Diseases, Including HIV Infection (141-156)

Genital Human Papillomavirus Infection (157-170)

Herpes Simplex Virus Infections of Women and Their Offspring: Implications for a Developed Society (171-188)

Human Ecology and Behavior and Sexually Transmitted Bacterial Infections (189-212)

Vaccines for Bacterial Sexually Transmitted Infections: A Realistic Goal? (213-234)

Quest for Life-Long Protection by Vaccination (235-248)

Index (249-256)