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in El Salvador, Honduras, and Nicaragua. Likewise, Jamaica, Haiti, the Dominican Republic, the Lesser Antilles Islands, and Venezuela reported little or no transmission. This lack of information is misleading, however, because dengue transmission was documented in many of the countries that did not report cases. Moreover, circulation of multiple virus serotypes was confirmed in the Dominican Republic and Venezuela, and cases of severe hemorrhagic disease were confirmed in the Dominican Republic and St. Lucia.

Clinically, most of the illness reported in the Americas in 1986 was still of the classical type. However, DHF was more widespread in 1986, and the trend of yearly increases in sporadically occurring cases of severe hemorrhagic disease has continued. Thus, in 1986 fatal DHF was confirmed in Brazil (4 cases) and Puerto Rico (3 cases). In addition, Puerto Rico had 26 other cases that met the World Health Organization criteria for DHF. Nicaragua, Mexico, the Dominican Republic, and St. Lucia all had sporadically occurring cases of confirmed or suspected DHF. Reported by: Pan American Health Organization, Washington, DC. Caribbean Epidemiology Center, Port of Spain, Trinidad. Pasteur Institute, Cayenne, French Guiana. Instituto de Salubridad y Enfermedades Tropicales, Mexico City, Mexico. Instituto Nacional de Salud, Bogotá, Colombia. Instituto Nacional de Higiene "Rafael Rangel," Caracas, Venezuela. "Boletin Epidemiologico," Honduras. Puerto Rico Dept of Health, San Juan. Dengue Br, Div of Vector-Borne Viral Diseases, Center for Infectious Diseases, CDC.

Editorial Note: The epidemiology of dengue in the American region is changing. The incidence of dengue in most countries of the region has continued to increase in recent years because of the simultaneous circulation of multiple virus serotypes. This increased incidence has led to the emergence of DHF in many countries of the region. Current surveillance and epidemiologic data suggest that the disease pattern associated with dengue infection in the Americas is evolving in a manner similar to the pattern that developed in southeast Asia in the 1960s, when DHF was first recognized. Although DHF originally began occurring sporadically, it is now a leading cause of hospitalization and death among children in many countries of southeast Asia (3). To avoid DHF epidemics of the magnitude of the 1981 Cuban epidemic, prevention and control programs need to be implemented in the Americas.

A second factor involved in the changing epidemiology of DHF in the Americas is the recent introduction of Aedes albopictus into the western hemisphere (4). This species has now spread to 17 states in the continental United States and to three states in Brazil. Infestations in other American countries have not yet been documented, although individual specimens of Ae. albopictus were identified in imported truck tires in Barbados. The presence of this mosquito species makes the epidemiology of dengue and DHF in the American region similar to that in southeast Asia. While the ultimate significance of the presence of Ae. albopictus is not known, it is likely to increase the efficiency of virus maintenance in infested areas. Such an occurrence may result in the increased incidence of dengue infection and, therefore, increase the probability of more severe disease.

References

1. Centers for Disease Control. Dengue - the Americas, 1984. MMWR 1986;35:51-2,57. 2. Centers for Disease Control. Dengue in the Americas, 1985. MMWR 1986;35:732-3.

3. World Health Organization. Dengue hemorrhagic fever: diagnosis, treatment and control. Geneva: World Health Organization, 1986.

4. Centers for Disease Control. Update: Aedes albopictus infestation - United States. MMWR 1987;36:769-73.

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The Morbidity and Mortality Weekly Report is prepared by the Centers for Disease Control, Atlanta, Georgia, and available on a paid subscription basis from the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402, (202) 783-3238.

The data in this report are provisional, based on weekly reports to CDC by state health departments. The reporting week concludes at close of business on Friday; compiled data on a national basis are officially released to the public on the succeeding Friday. The editor welcomes accounts of interesting cases, outbreaks, environmental hazards, or other public health problems of current interest to health officials. Such reports and any other matters pertaining to editorial or other textual considerations should be addressed to: Editor, Morbidity and Mortality Weekly Report, Centers for Disease Control, Atlanta, Georgia 30333.

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Condoms for Prevention of Sexually Transmitted Diseases*
PUBLIC HEALTH LIBRARY

Introduction

Prevention is the most effective strategy for controlling the spread of infectious diseases. Prevention through avoiding exposure is the best strategy for controlling the spread of sexually transmitted disease (STD). Behavior that eliminates or reduces the risk of one STD will likely reduce the risk of all STDs. Prevention of one case of STD can result in the prevention of many subsequent cases. Abstinence and sexual intercourse with one mutually faithful uninfected partner are the only totally effective prevention strategies. Proper use of condoms with each act of sexual intercourse can reduce, but not eliminate, risk of STD. Individuals likely to become infected or known to be infected with human immunodeficiency virus (HIV) should be aware that condom use cannot completely eliminate the risk of transmission to themselves or to others.

Efficacy

For the wearer, condoms provide a mechanical barrier that should reduce the risk of infections acquired through penile exposure to infectious cervical, vaginal, vulvar, or rectal secretions or lesions. For the wearer's partner, proper use of condoms should prevent semen deposition, contact with urethral discharge, and exposure to lesions on the head or shaft of the penis. For infectious agents spread from lesions rather than fluids, condoms may offer less protection because areas of skin not covered by the condom may be infectious or vulnerable to infection.

*This summary includes data presented at a conference entitled "Condoms in the Prevention of Sexually Transmitted Diseases" sponsored by the American Social Health Association, Family Health International, and the Centers for Disease Control and held in Atlanta, Georgia, February 20-21, 1987. The following consultants assisted in the formulation of these data and strategies: J Cohen, PhD, M Conant, MD, University of California; L Pappas, San Francisco AIDS Foundation, San Francisco, California. F Judson, MD, Disease Control Service and University of Colorado, Denver, Colorado. J Graves, M Rosenberg, MD, American Social Health Association; M Potts, MD, Family Health International, Research Triangle Park, North Carolina. P Harvey, Population Services International, Washington, DC. L Liskin, Johns Hopkins University, Baltimore, Maryland. M Solomon, Solomon Associates, Sudbury, Maine.

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES/PUBLIC HEALTH SERVICE

U.S. DEPOSITORY MAR 25 1989

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Laboratory and epidemiologic studies have provided information about the effectiveness of condoms in preventing STD. Laboratory tests have shown latex condoms to be effective mechanical barriers to HIV (1), herpes simplex virus (HSV) (2-4), cytomegalovirus (CMV) (5), hepatitis B virus (HBV) (6), Chlamydia trachomatis (2), and Neisseria gonorrhoeae (4). Latex condoms blocked passage of HBV and HIV in laboratory studies, but natural membrane condoms (made from lamb cecum), which contain small pores, did not (6-8). The experimental conditions employed in these studies may be more extreme than those encountered in actual use; however, they suggest that latex condoms afford greater protection against viral STD than do natural membrane condoms.

The actual effectiveness of condom use in STD prevention is more difficult to assess. It is difficult to determine if a user has been exposed to an infected partner or whether the condom was correctly used. However, several cross-sectional and case-control studies have shown that condom users and/or their partners have a lower frequency of gonorrhea, ureaplasma infection, pelvic inflammatory disease, and cervical cancer than persons who do not use condoms (9). Consistent previous condom use was associated with seronegativity during the 1- to 3-year follow-up period in a recent study of HIV antibody-negative heterosexual spouses of patients with acquired immunodeficiency syndrome (AIDS) (10). Another recent investigation of prostitutes in Zaire has also suggested a protective association between a history of condom use and HIV seronegativity (11).

Condoms are not always effective in preventing STD. Failure of condoms to protect against STD is probably explained by user failure more often than by product failure. User failure includes failure to: 1) use a condom with each act of sexual intercourse, 2) put the condom on before any genital contact occurs, and 3) completely unroll the condom. Other user behaviors that may contribute to condom breakage include: inadequate lubrication, use of oil-based lubricants that weaken latex, and inadequate space at the tip of the condom. Product failure refers to condom breakage or leakage due to deterioration or poor manufacturing quality. Deterioration may result from age or improper postmanufacturing storage conditions. No scientific data on the frequency or causes of condom breakage are available. Likewise, no data are available comparing the susceptibility to breakage of condoms of various sizes, thicknesses, or types, i.e., natural versus latex, lubricated versus nonlubricated, or ribbed versus smooth. Experimental methods need to be developed to test the factors associated with breakage. Such information is necessary to provide users with accurate instructions on proper condom use.

Quality Assurance

Since 1976, condoms have been regulated under the Medical Device Amendments to the Federal Food, Drug, and Cosmetic Act. Within the Food and Drug Administration (FDA), the Center for Devices and Radiological Health is responsible for assuring the safety and effectiveness of condoms as medical devices. Beginning in the spring of 1987, FDA undertook an expanded program to inspect latex condom manufacturers, repackagers, and importers to evaluate their quality control and testing procedures. In its testing of condoms, FDA uses a water-leak test in which a condom is filled with 300 mL of water and checked for leaks. The FDA has also adapted its inspection sampling criteria to conform with the American Society for Testing and Materials Standard D3492-83 for latex condoms. FDA criteria and the industry acceptable quality level (AQL) for condoms specify that, in any given batch, the failure rate due

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to water leakage cannot exceed four condoms per thousand. Batches exceeding the specified rejection criteria are recalled or barred from sale. Among batches of condoms that have met the AQL, the average failure rate observed was 2.3/1,000.

As of February 1988, FDA had examined samples from 430 batches of domestically produced and foreign-made condoms. These examinations have resulted in the testing of over 102,000 condoms. In FDA's sampling methodology, the sample size is determined by the size of the batch of condoms introduced into the market, the inspection level, and the AQL. Approximately 38,000 domestically produced condoms from 165 different batches of condoms were tested. Nineteen of those batches (approximately 12%) had leakage rates of over 4/1,000 and failed the test. By contrast, approximately 21% of the 265 foreign-manufactured batches failed to meet AQL standards. Thus far, as a result of both FDA's sampling program and the manufacturers' quality assurance programs, four domestic manufacturers have conducted 16 condom recalls.

FDA samples foreign-made condoms before they are passed through U.S. customs. If two or more of a given foreign manufacturer's batches offered for import are found to have leakage rates of more than 4/1,000, future shipments from that manufacturer are automatically detained at the port of entry. Seven foreign firms are presently on this automatic detention list. FDA also has the authority to seize any lot that is found to be violative if the manufacturer or importer does not take appropriate action.

Use of Spermicides with Condoms

The active ingredients (surfactants) in commercially available spermicides have been shown in the laboratory to inactivate sexually transmitted agents, including HIV (9,12,13). Vaginal use of spermicides is associated with a lower risk of gonorrhea and chlamydial infection in epidemiologic studies of women (9,14). The use of spermicide-containing condoms may provide additional protection against STD in the event of condom leakage or seepage. However, the spermicidal barrier would no longer be in place if the condom breaks. If extra protection is desired, vaginal application of spermicide is likely to afford greater protection than the use of spermicide in the condom because a larger volume of spermicide would already be in place in the event of condom breakage. Neither the safety nor the efficacy of spermicides in preventing sexually transmitted infections of the anal canal or oropharynx has been studied.

Prevalence of Use

Recent studies suggest that condom use for STD prevention is increasing in selected populations but is still infrequent. In 1985, a sample of New York City male homosexuals reported a significant increase in condom use with both insertive and receptive anal intercourse after the respondents became aware of AIDS (15). In the year before learning of AIDS, the men used condoms an average of 1% of the time when engaging in insertive anal intercourse; in the ensuing year, 20% of respondents reported consistent condom use. In 1984, 39% of the men in a prospective study in San Francisco reported having anal intercourse; 26% of these men used condoms (16). In April 1987, 19% of the San Francisco respondents reported anal intercourse; 79% used condoms. The trends in condom use for STD prevention among heterosexual men and women are unknown. In a 1986-87 survey of female prostitutes in the United States, 4% reported condom use with each vaginal exposure (17).

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