The distribution of reported dengue-like illness (Figure 2) demonstrates that activity is widespread. Thirty of the 79 municipalities on the island have reported dengue-like illness through the surveillance system; dengue has been confirmed in 9 of these 30. A few dengue-like illnesses have been reported from 10 additional municipalities (Figure 2), but no clinical data or serological specimens were collected from these cases.

A total of 8 presumptive dengue viruses have been isolated from sera of acute cases. Four of these were shown to

be dengue-2 by the complement fixation (CF) test; definitive identification is pending on the other 4.

To date, 3 cases of dengue hemorrhagic fever (DHF) have been documented; all 3 patients recovered. The 2 cases of suspect dengue shock syndrome previously reported (MMWR 24:[49]) were not confirmed by laboratory tests.

The first patient with DHF was a 35-year-old man who experienced gross hematuria a week after the onset of dengue-like illness. The second patient, a 45-year-old man, developed severe bleeding from the gums 5 days after the onset of a dengue-like illness, followed by widespread petechiae, ecchymoses, profound thrombocytopenia (4,000 platelets/mm3), and a positive tourniquet test. In the third and most recent case, a 14-year-old male developed, several days after the onset of a dengue-like illness, petechiae on the palate, epistaxis, a positive tourniquet test, and thrombocytopenia (88,000/mm3). Serological studies by hemagglutination inhibition (HI) and/or CF tests have shown typical secondary type serological responses for cases 1 and 3. In case 2, HI, CF, and plaque reduction neutralization antibody titers were all exceedingly high to dengue-2, but titers to the other 3 dengue types were relatively low, and therefore not typical of a broad secondary serologic response.

Aerial spraying with ultra low volume (ULV) Malathion (3 oz per acre) began in the San Juan metropolitan area on December 11 and has been repeated twice at approximately 1-week intervals. The spraying activities, as measured by adult mosquito collections and by mortality of caged mosquitoes, have reduced adult Aedes aegypti populations. Evaluation of mosquito control activities is also in progress with ovitraps. Although it is too early to assess the impact of aerial spraying on dengue transmission in the San Juan metropolitan area, early data suggest a considerable decline in new cases.

(Reported by H Morales, MD, Hospital Maestro; JE Madera, MD, Bayamón Subregional Hospital; CH Ramirez-Ronda, MD, R Bermudez, MD, Veterans Admin Hospital; V Gonzáles, MD, State Epidemiologist, H Romney, State Dept of Health, Puerto Rico; San Juan Laboratories, Bur of Laboratories, Vector Biology and Control Div, Bur of Tropical Diseases, and Field Services Div, Bur of Epidemiology, CDC.)

Since January 1971, the Center for Disease Control has provided Zoster Immune Globulin (ZIG) as an investigational drug to high risk, susceptible children who have been exposed to varicella zoster within the previous 72 hours. ZIG is prepared from the plasma of healthy donors convalescing from herpes zoster. The current supply of ZIG will soon be exhausted.

Almost certainly, ZIG will not be available during February and March. These are the peak months of varicella activity. CDC urgently needs donors. If requested, CDC will provide financial reimbursement for plasmapheresis of ac