What people do when they have symptoms or suspicion of a sexually transmitted disease (STD) has major implications for transmission and, consequently, for disease control. Delays in seeking and obtaining diagnosis and treatment can allow for continued transmission and the greater probability of adverse sequelae. An understanding of health seeking behaviour is therefore important if STD control programmes are to be effective. However, taboos and stigma related to sex and STD in most cultures mean that gaining a true picture is difficult and requires considerable cultural sensitivity. At the moment relatively little is known about who people turn to for advice, or about how symptoms are perceived, recognized or related to decisions to seek help. It is argued that such knowledge would assist programme planners in the development of more accessible and effective services, that studies of health seeking behaviour need to include a combination of qualitative and quantitative methods, and that studies should include data collection about people who do not present to health care facilities as well as those who do. A pilot protocol for studying STD-related health seeking behaviour in developing countries is briefly presented.

Numerous studies performed over the past 5 years have indicated an association between HIV infection and other sexually transmitted diseases (STDs), particularly those involving genital ulceration. Such an association may be causal, indicating that STDs increase susceptibility to, or infectivity of, HIV infection or may result, in whole or in part, from the mutual dependence of HIV and STDs on patterns of sexual activity, or from an effect of HIV infection on the clinical course of STDs. In this paper we discuss the issues arising in the design and analysis of studies conducted to investigate this association. A numerical illustration is used to demonstrate non-causal associations that may arise in observational studies due to confounding and misclassification. Published cross-sectional and longitudinal studies are reviewed, and recommendations made for future studies. Special emphasis is given to the use of randomized intervention trials to overcome many of the biases associated with observational studies, and to provide information on the efficacy of intensive STD treatment programmes in reducing the transmission of HIV.