Conjunctivitis - Continued

AHC has been associated, on rare occasions, with neurological complications (3). Such complications were not reported during this outbreak, nor have they been reported in conjunction with CA24v-induced AHC in the past. The clinical characteristics of AHC caused by Ad11 are nearly identical to those caused by EV70 and CA24v, but the incubation period and the illness are slightly longer (1).

The etiologic agent of an outbreak of AHC can be identified by serologic studies of all three viruses and by isolation studies of Ad11 and CA24v. In recent years, EV70 has been difficult to isolate, even when cases have been serologically confirmed (1).

CA24v has caused large outbreaks of AHC in areas with tropical climates, such as Southeast Asia and the Indian Subcontinent (1). In 1986, CA24v was isolated in Taiwan, American Samoa (CDC, unpublished data), and India (4). CA24v was first isolated in the Western Hemisphere during the period October-November 1986, in Trinidad, Jamaica, and St. Croix (5). Subsequently, CA24v has been isolated from patients with AHC in Panama (6) and Mexico (CDC, unpublished data). References

1. Hierholzer JC, Hatch MH. Acute hemorrhagic conjunctivitis. In: Darrell RW, ed. Viral diseases of the eye. Philadelphia: Lea & Febiger, 1985:165-96.

2. Melnick JL. Enteroviruses. In: Evans AS, ed. Viral infections of humans: epidemiology and control. 2nd ed. New York: Plenum Publishing, 1984:187-251.

3. Kono R, Miyamura K, Tajiri E, et al. Virological and serological studies of neurological complications of acute hemorrhagic fever in Thailand. J Infect Dis 1977;135:706-13.

4. ICMR Centre of Virology. An outbreak at [sic] acute viral conjunctivitis in October-November 1986. North Arcot District [India] Health Information 1986; Dec:6-7.

5. Centers for Disease Control. Acute hemorrhagic conjunctivitis caused by Coxsackievirus A24-Caribbean. MMWR 1987;36:245-6, 251.

6. Baynard V, ed. Aumento de conjunctivitis en la Region Metropolitana. Boletin Epidemiologico 1987;2(5):1-4.

Dengue and Dengue Hemorrhagic Fever in the Americas, 1986

Dengue activity in the American region was higher in 1986 than in other recent years. A total of 88,750 cases was reported (Table 1), whereas 68,998 cases had been reported in 1985, and 43,435, in 1984 (1,2). Because of underreporting in many countries, however, the 1986 figure is probably underestimated. In Brazil and Puerto Rico, for example, seroepidemiologic studies indicated that the actual number of dengue infections was many times higher than that reported.

As in previous years, three virus serotypes (DEN-1, DEN-2, and DEN-4) circulated in the region. DEN-2 had the most widespread distribution but was responsible only for small outbreaks in Suriname, French Guiana, and the U.S. Virgin Islands. DEN-1 and DEN-4 were again responsible for the major epidemics in which the virus serotypes were known. Four countries (Mexico, the Dominican Republic, Puerto Rico, and Venezuela) had three virus serotypes circulating simultaneously in 1986.

The large epidemic in Brazil in 1986 was caused by DEN-1. Transmission began in the Rio de Janeiro area in February and was confirmed in Fortaleza and Maceió on the northeastern coast by late summer. Seroepidemiologic studies carried out in two cities in the Rio de Janeiro area indicated that 216,480 dengue infections occurred between March and the end of May. Brazilian health authorities estimated the total number of dengue infections in 1986 at between 300,000 and 500,000.

Dengue - Continued

Mexico continued to have high levels of dengue transmission in 1986, with outbreaks occurring in Veracruz in the east; Nuevo León in the north; Oaxaca in the south; Colima, Jalisco, and Nayarit on the west coast; and Puebla and Morelos in the central part of the country. Three dengue serotypes (DEN-1, DEN-2, and DEN-4) continued to circulate in Mexico, although the outbreaks were all associated with DEN-1 and DEN-4. Some outbreaks occurred at high altitudes (1,500 meters), in Oaxaca and Puebla.

Puerto Rico had a larger number of cases of dengue hemorrhagic fever (DHF) during the 1986 epidemic than at any other time in the past. Multiple virus serotypes (DEN-1, DEN-2, and DEN-4) circulated, but DEN-4 was the predominant virus. Peak transmission occurred during the period September-October, and most of the cases occurred in the San Juan metropolitan area. Officials received reports of 10,659 cases of dengue, but seroepidemiologic studies indicated that between 377,000 and 555,000 dengue infections occurred in 1986. These findings indicate considerable underreporting by the medical community.

Complete details of the dengue outbreaks in Colombia are not available. However, a mixed outbreak of DEN-1 and DEN-2 occurred in the port city of Tumaco in late 1985 and early 1986. Also, a DEN-1 epidemic in Cali began in late 1986 and continued into 1987.

Surveillance data for other countries in the region are incomplete. No information was made available from Guatemala and Belize. Low-level transmission was reported

TABLE 1. Cases of dengue in the Americas, by country, 1986

Dengue - Continued

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.

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.

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. Jodson, MP, Mss 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, Wash, BCLskin, Johns Hopkins University, Baltimore, Maryland. M Solomon, Solomon Associates, Sudbury, Maine.

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