The 1986 dengue and dengue hemorrhagic fever epidemic in Puerto Rico: epidemiologic and clinical observations.

In 1986 Puerto Rico experienced its eleventh dengue outbreak of this century, but the first with simultaneous transmission of three dengue virus serotypes, and the first with significant numbers of severe and fatal hemorrhagic disease. Overall, 10,659 cases were reported; 1,257 cases were laboratory confirmed as having current or recent dengue infection. Dengue 4 (DEN-4) was the predominant serotype (160/363 isolates, 44%) followed by dengue 1 (DEN-1) with 134 isolates (37%) and dengue 2 (DEN-2), 69 isolates (19%).

Dengue shock syndrome in an American traveler with primary dengue 3 infection.

A previously reported case of childhood dengue shock syndrome in an American traveler to India was investigated serologically. The original studies neither indicated the infecting serotype nor proved primary or secondary infection. However, BHK suspension PRNT of 6-year convalescent serum now indicates that the child had primary dengue type 3 infection.

Dengue 3 virus transmission in Africa.

The first known transmission of dengue 3 virus in Africa was documented by virus isolation during an epidemic of dengue-like illness in Pemba, Mozambique, in late 1984 and early 1985. Dengue 3 virus was the only serotype isolated. Most patients appeared to be experiencing secondary flavivirus infections, but whether this was the result of previous dengue, yellow fever, or other flavivirus infection is not known.

Dengue in Puerto Rico, 1977: public health response to characterize and control an epidemic of multiple serotypes.

The largest and most extensive documented dengue epidemic in Puerto Rico struck an estimated 355,000 Puerto Rican residents from July-December 1977. The mixed epidemic of dengue types 2 and 3 coincided with a Caribbean pandemic of dengue type 1, first introduced into the western hemisphere in early 1977 and into Puerto Rico in the fall of that year. Health officials assembled a team to assess the epidemic and mounted a campaign to end it.

Dengue transmission in two Puerto Rican communities in 1982.

Paired serologic, entomologic, and environmental surveys were performed in two Puerto Rican communities, Salinas and Manatí, in summer and fall 1982. Paired samples on 434 persons in Salinas and 324 persons in Manatí showed recent dengue infection rates of 35% and 26%, respectively. Ae.

Low rates of antigen detection and virus isolation from the peripheral blood leukocytes of dengue fever patients.

We evaluated direct fluorescent antibody (FA) testing of peripheral blood leukocytes (PBL) from patients in Puerto Rico with serologically and/or virologically confirmed dengue fever as a possible rapid diagnostic test and compared rates of dengue virus isolation from PBL with the rates from plasma or serum using the mosquito inoculation technique. Dengue antigen was detected in the PBL of only 1 of 19 patients with confirmed dengue. Virus was isolated from 3 of 19 PBL specimens and from 6 of 19 acute-phase serum or plasma samples.

A case of natural concurrent human infection with two dengue viruses.

The first documented case of concurrent human infection with 2 dengue viruses is reported. Dengue 1 and 4 viruses were isolated from the serum of a 16-year-old male during the 1982 outbreak in Puerto Rico. The illness was mild and does not support the hypothesis that double infection with dengue viruses leads to more severe hemorrhagic disease.

Mosquito cell cultures and specific monoclonal antibodies in surveillance for dengue viruses.

During the fall of 1981, a new method for the routine isolation and identification of dengue viruses in Puerto Rico was implemented utilizing C6/36 cell cultures and serotype specific antidengue monoclonal antibodies. A blind comparison of the monoclonal antibody indirect fluorescent antibody test (IFAT) and the complement fixation (CF) test for identification of 89 newly isolated dengue viruses of all four serotypes from the Caribbean, Asia and Africa showed 100% agreement. Although virus isolation rates were slightly lower than with the mosquito inoculation technique, use of the C6/36 cell culture system was much less time-consuming and allowed the processing of larger numbers of sera.

Epidemiologic investigations of dengue infection in Mexico, 1980.

A binational investigation was conducted in two Mexican cities in 1980 to study epidemiologic characteristics of dengue. Two study areas were selected in each of the cities (Merida and Tampico); in each area, in February and in September, sanitarians recorded information concerning abundance of Aedes aegypti, and public health nurses obtained blood specimens and clinical information from residents. Ninety-nine individuals (24% of the study population) showed serologic evidence of recent dengue 1 infection by hemagglutination inhibition or complement fixation.

Reintroduction of dengue fever into the continental United States. I. Dengue surveillance in Texas, 1980.

Two surveillance systems were initiated in Texas in 1980 to detect cases of dengue fever. Physicians throughout the state were requested to report cases of dengue (passive surveillance), and 27 out-patient facilities serving geographically and ethnically high risk populations were asked to report cases of dengue-like illness weekly (active surveillance). Additionally, two clinics participating in active surveillance submitted acute-phase blood specimens weekly for dengue virus isolation.

Lack of greater seroconversion of rhesus monkeys after subcutaneous inoculation of dengue type 2 live-virus vaccine combined with infection-enhancing antibodies.

Four groups of six nonimmune male rhesus monkeys were inoculated subcutaneously with formulations of dengue type 2 vaccine virus DEN-2/S-1. Group A received 1.9 x 10(4) plaque-forming units of vaccine in normal human serum albumin diluent.

Factors affecting syncytial development in Aedes pseudoscutellaris cells by dengue viruses.

Several factors that were suspected of affecting the development of syncytia in cultured Aedes pseudoscutellaris cells inoculated with dengue viruses were studied. The results indicated that fresh media (less than 1 week old), low cell density at inoculation (2.8 x 10(5) cells/cm2), and low cell passage level (less than 52 passages) favored the development of syncytia.

Prevalence of selected zoonotic diseases in vertebrates from Haiti, 1972.

Vertebrate animals collected in Haiti in 1972 were tested for selected zoonotic diseases. No rabies virus or neutralizing (N) antibody was detected in bats (Artibeus jamaicensis). However, N antibody against St.

Dengue hemorrhagic shock in the western hemisphere.

A 39-year-old man after visiting an endemic dengue area during a local outbreak developed a febrile illness complicated by skin petechiae, bleeding, shock, hemoconcentration, and death. The presumptive diagnosis of dengue was made based on hemagglutination inhibition and complement fixation titers in a single sample. The serologic evidence and ancillary laboratory findings are compatible with a secondary antibody response.

A rapid fluorescent focus-inhibition test for determining dengue neutralizing antibody and for identifying prototype dengue viruses.

Neutralizing antibody to dengue virus in human and animal sera was assayed by the rapid fluorescent focus-inhibition test (RFFIT). Neutralizing-antibody titers could be detected after only 24 h compared to 5--6 days required by the plaque-reduction test. The RFFIT is more definitive than the conventional complement fixation (CF) or hemagglutination-inhibition (HI) test in identifying prototype dengue viruses, is reproducible, and is applicable to the routine detection of neutralizing antibodies to dengue viruses.

Dengue fever with hemorrhagic manifestations: a report of three cases from Puerto Rico.

During the 1975 dengue epidemic in Puerto Rico, we studied three patients who had serologically confirmed dengue with hemorrhagic manifestations. None of the patients went into shock and none died. Only one of the patients had disease that resembled dengue hemorrhagic fever (DHF) as observed in Southeast Asia.

Venezuelan equine encephalitis vaccination survey in Arizona and New Mexico, 1972.

Field studies were conducted in 1972 to determine the immunization status of equines along the Mexico, Arizona, and New Mexico borders. Interviews with horse owners were conducted along roads selected at random in the counties of Santa Cruz and Yuma, Ariz., and in Dona Ana County, N.

Dengue outbreaks in Guánica-Ensenada and Villalba, Puerto Rico, 1972-1973.

Epidemics of dengue fever occurring in Puerto Rico in 1963 to 1964 and 1969 were caused by dengue-3 and dengue-2 (DN-2) viruses, respectively, but endemic dengue transmission has never been documented on the Island. Since the 1969 epidemic, a surveillance system has detected DN-2 activity on the Island during each of the years 1970 through 1973, which suggests endemic persistence of the virus. This report describes the investigation of localized outbreaks of DN-2 in Guanica-Ensenada (1972) and Villalba (1973), and presents epidemiological, serological, and virological data from the outbreaks.

Epidemic Venezuelan equine encephalitis in North America in 1971: vertebrate field studies.

Epidemic Venezuelan equine encephalitis in North America in 1971: vertebrate field studies. Am J Epidemiol 101:36-50, 1975.-In June 1971, epidemic Venezuelan equine encephalitis (VEE) invaded the lower Rio Grande Valley in south Texas.

Possible evidence for interference with Venezuelan equine encephalitis virus vaccination of equines by pre-existing antibody to Eastern or Western Equine encephalitis virus, or both.

During 1971, an epizootic of Venezuelan equine encephalitis (VEE) reached the United States. Laboratory tests were performed on a large number of sick, healthy, unvaccinated, and vaccinated horses. Neutralization (N) tests in cell cultures revealed that 153 of 193 (79.