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At least 19 recordsLinked to original sources
PubMed1995

[The risk of dengue transmission: a space for stratification].

The emergence of dengue fever as a public health problem in the Americas is increasing. Its rapid spread in the region and the geographical dissemination of dengue infection has not been followed by a corresponding input of financial, human and technical resources necessary to control dengue fever epidemics. This situation compelled to the analysis of dengue transmission in Mexico with the objective of designing a strategy of dengue fever surveillance based on the stratification of transmission risks taking into account geographical variables like climate, rain precipitation, mean annual temperature and altitude, as well as socio-demographical variables like population density and socio-economic level. This strategy will permit the efficient use of the scant resources available for control, although the impact of dengue transmission is yet to be evaluated.

Adolescent↗
PubMed1985

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. aegypti larval indices were higher in Salinas than in Manatí but were relatively high throughout both communities. Breteau indices in neighborhoods ranged from 43 to 172, and infection rates in the neighborhoods were 22% to 45%. With a multivariate technique, we analyzed possible associations of environmental variables with dengue incidence and prevalence of dengue antibody. Wood-constructed housing and low socioeconomic status were among the variables significantly associated with dengue incidence. Predictors of dengue antibody prevalence included socioeconomic level, tree height, shade, and window and door screens. Recent dengue infections clustered within the sampled members of households (P less than 0.05, binomial test). An estimated 35% of dengue infections were symptomatic, and no serious illnesses were reported. The potential for high dengue infection rates in Puerto Rico will continue unless substantial reductions in vector populations are achieved. Targeting dengue surveillance and vector control activities in areas with demonstrated environmental risk factors may limit transmission during future outbreaks.

Adolescent↗
PubMed1983

Dengue fever in the United States. A report of a cluster of imported cases and review of the clinical, epidemiologic, and public health aspects of the disease.

In the United States during 1981, fourteen state health departments reported a total of 44 imported cases of dengue fever. Most originated in the Caribbean, where dengue type 4 has reached pandemic proportions. Because the mosquito vector for dengue is abundant throughout the southeast and imported cases continue to occur, the possibility exists for indigenous dengue transmission. We report a cluster of imported dengue type 1 cases in Florida, discuss the clinical, epidemiologic, and public health aspects of the disease, and make recommendations as to how clinicians can assist public health officials in minimizing the risk of indigenous dengue transmission in the United States.

Adult↗
PubMedDate not supplied

Effect of a community-based Aedes aegypti control programme on mosquito larval production sites in El Progreso, Honduras.

This paper describes the results of a trial to assess the efficacy in reducing the density of larval production sites of utilizing community involvement in the planning and implementation of an Aedes aegypti control programme, in a dengue-endemic city in Honduras. In addition to a substantial increase in knowledge about dengue transmission and prevention, a relative reduction in Ae. aegypti larval infestation indices was found in those city neighbourhoods where community involvement was utilized compared with their untreated counterparts. Several methods of improving the impact of this type of programme are discussed.

Aedes↗
PubMed2026

Genomic epidemiology of dengue virus 2 and 3 reveals repeated introductions and exportations of several lineages in Colombia.

Dengue fever, a major mosquito-borne viral disease, is transmitted by Aedes mosquitoes and poses a significant global health burden. Despite extensive research, the spatiotemporal dynamics of dengue virus (DENV) lineages in Colombia remain understudied. Here, we analyze 11,443 complete genome sequences from Colombia and the Americas to map the genomic epidemiology of DENV-2 and DENV-3. Phylogeographic reconstruction revealed multiple independent introductions and exportations of the DENV-2 II and III lineages, as well as the DENV-3 lineage III_C.2, underscoring Colombia's critical role as both a source and a sink of viral traffic within the Americas. Antigenic profiling demonstrated distinct clustering of emergent lineages in antigenic space, consistent with immune-escape-driven turnover. These results highlight the necessity of sustained, high-resolution genomic surveillance to guide targeted public health interventions and mitigate dengue transmission across the region.

Dengue Virus↗
PubMed1993

Distribution of container-inhabiting Aedes larvae (Diptera: Culicidae) at a dengue focus in Thailand.

A Thai village with dengue transmission was surveyed for Aedes aegypti (L.) and Ae. albopictus (Skuse) larvae at the end of the rainy season. All containers (1,819) in 186 households were surveyed, recording the presence of larvae, container type, level of water, kind of cover, and location. The number of positive containers was proportional to the total number of containers in a household. Standard water jars (approximately 200 liters) contributed 57% and small water jars (< 100 liters) contributed 16% of the total infested containers. Each of the other 10 container types contributed < or = 10% of the total infested containers and were not statistically different from each other. Containers inside houses were infested significantly more often than were those outdoors, those under elevated houses or roofs, or those in bathrooms. Unexpectedly, standard water jars located outdoors that were covered with commercial metal lids were infested significantly more often than were uncovered jars.

Aedes↗
PubMed1983

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. Infection rates in the four study areas (9%-51%) increased with age in three of the four areas and were higher in females in all four areas. These differences in rates may be related to exposure to infectious mosquitoes in the home; A. aegypti feed most actively during daylight hours, and both females (p less than 0.001) and older individuals (p less than 0.001) were more likely than males or younger persons to be in the home when the study was conducted. A positive correlation was found between infection rates and the container index (number of potential A. aegypti breeding sites per premise--Pearson correlation coefficient 0.95, p = 0.05), suggesting that this index may be a useful predictor of neighborhoods at high risk of dengue transmission. Pending additional studies, public cleanup campaigns should be targeted to neighborhoods in which container indices are highest when an outbreak of dengue is likely to occur.

Adolescent↗
PubMed1991

Determinants and predictors of dengue infection in Mexico.

A national serosurvey was conducted in Mexico from March to October 1986 to identify predictors of dengue transmission and target areas at high risk of severe annual epidemics. A total of 3,408 households in 70 localities with populations less than 50,000 were randomly sampled, and serology was obtained from one subject under age 25 years in each household. When comparing exposure and infection frequencies across the 70 communities, the authors found that median temperature during the rainy season was the strongest predictor of dengue infection, with an adjusted fourfold risk in the comparison of 30 degrees C with 17 degrees C. High temperatures increase vector efficiency by reducing the period of viral replication in mosquitoes. The proportion of houses in a community with larva on the premises was significantly associated with the community proportion infected (odds ratio (OR)adj = 1.9; 95% confidence interval (CI) 1.4-2.5), as was the proportion of households with uncovered water containers present (ORadj = 1.9; 95% CI 1.4-2.7). Because these factors have effects beyond the individual household and subjects infected from them create a risk for other subjects, both analyses of effects and organization of control efforts must be at the community level. A predictive model was constructed using the community level risk factors to classify communities as being at high, medium, or low risk of experiencing an epidemic; 57% of these communities were correctly classified using this model.

Adult↗
PubMed1993

Lessons of Aedes aegypti control in Thailand.

The incidence of dengue haemorrhagic fever (DHF) in Thailand has increased cyclically since the first recognized outbreak in 1958. Without an effective vaccine against dengue, and considering the clinical difficulty of treating DHF cases, vector control is needed to prevent dengue transmission. Since the establishment of the WHO Aedes Research Unit in 1964, continued since 1973 as the WHO Collaborating Centre at the Department of Medical Research in Bangkok, much operational research has been carried out in Thailand on the bionomics and control of dengue vectors: Aedes aegypti and Ae. albopictus. This review shows that, as in most other countries, dengue vector control programmes in Thailand make little use of the procedures arising from research, nor have they reduced the upward trend of dengue or prevented DHF outbreaks. Implications of the reluctance to use results of operational research on vector control are considered and remedial suggestions made.

Aedes↗
PubMed1976

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. Analysis of geographic distribution of dengue activity in Puerto Rico in recent years indicates that the DN-2 transmission in 1970 to 1973 may represent a long tail-off of the 1969 epidemic rather than the emergence of a truly endemic situation.

Adolescent↗
PubMed1995

Risk factors for dengue infection during an outbreak in Yanes, Puerto Rico in 1991.

In November 1991, during a five-month dengue outbreak, we performed epidemiologic and serologic surveys linked to an earlier entomologic study in a community of 425 houses in Yanes (Florida), Puerto Rico. We obtained a household response rate of 95% (98 of 103) and blood samples from 84% (345 of 410) of the participants. Dengue incidence, as volunteered by the respondents, was 5% (21 of 410), but serologic diagnosis (immunoglobulin M and IgG-enzyme-linked immunosorbent assays [ELISA]) indicated a recent infection rate of 18% (59 of 331). The presence of anti-dengue antibodies was detected in 277 (84%) of 331 persons tested. In our final sample of 65 households and 112 persons, we analyzed (by univariate and multivariate logistic regression methods) the association of 12 entomologic, environmental, and behavioral variables with the proportion of household members with laboratory-confirmed recent dengue. The number of female Aedes aegypti per person was the only significant (P = 0.02) household risk factor. The results of our study underscore the importance of intradomiciliary mosquito populations in dengue transmission, and may serve as a guide for mosquito control efforts.

Adolescent↗
PubMed1992

The XXth century dengue pandemic: need for surveillance and research.

By the last decade of the XXth century Aedes aegypti and the 4 dengue viruses had spread to nearly all countries of the tropical world. Some 2 billion persons live in dengue-endemic areas with tens of millions infected annually. Dengue pandemics were also documented in the XVIIIth and XIXth centuries; they were contained by organized anti-Aedes aegypti campaigns and urban improvements. The XXth century dengue pandemic has brought with it the simultaneous circulation of multiple serotypes and in its aftermath, endemic dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS). Nearly 3 million children have been hospitalized with this syndrome in the past 3 decades, mainly in South-East Asia. Recent outbreaks of DHF/DSS in the Pacific Islands, China, India, Sri Lanka, Cuba and Venezuela are indicators of the high intensity and rapid spread of dengue transmission. The magnitude of the XXth century dengue pandemic requires urgent improvements in early warning surveillance by WHO Member States and the development of the capacity to study underlying mechanisms of the disease. A key research question is why does DHF/DSS not occur with all second dengue infections? Two answers have been suggested: (1) a human resistance gene. Data from the 1981 DHF/DSS epidemic in Cuba have demonstrated the existence in blacks of a resistance gene. The effect of such a gene in reducing disease susceptibility of American and African blacks requires more study. (2) The existence of dengue "biotypes". Some, but not all biotypes may cause DHF/DSS during a second dengue infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Aedes↗
PubMedDate not supplied

[Dengue in the Americas. A problem of regional health].

The Aedes aegypti was almost eradicate from The Americas in the early sixties but reinfested the Region a few years later, and dengue transmission has become a major health problem. The Americas have been affected by dengue epidemics since the 1970s and hemorrhagic fever is becoming a threat for millions of people living in the tropical and subtropical areas of the continent. Resources to cope with the increasing transmission of different serotypes in the Region are scarce. Therefore a regional effort to prevent the dissemination of dengue hemorrhagic fever (DHF) is necessary. Public awareness and community participation must be promoted and enhanced in order to decrease the risk of DHF.

Aedes↗
PubMed1989

A practical community-based approach to the diagnosis of dengue virus infections.

A study is described in which private physicians participated in the surveillance and diagnosis for dengue disease within a community. Using simple, economical methods it was shown that a significant proportion of specimens submitted were positive for dengue infection. Of 610 fingerprick blood specimens collected on filter paper strips, 7% to 33% were positive by serology. Of these specimens, 423 (69%) were single specimens and 92 (22%) of the single specimens were positive by serology. Of 153 fingerprick blood specimens collected in heparinized, glass capillary tubes, 15% to 50% yielded a dengue virus isolate. When a positive result was based on serology and/or virus isolation, an overall positive rate of 39% was obtained for one of the participating clinics. Inclusion of thrombocytopenia and leukopenia in selection of cases significantly improved the positive rate. It is argued that this simple and practical community-based approach will result in more accurate surveillance of dengue transmission within an endemic area and thus aid in the development of long-term strategies for control of disease.

Dengue↗
PubMedDate not supplied

[Seasonal variations in Aedes Aegypti populations in Monterrey, Mexico].

Seasonal variation of the populations of the dengue vector mosquito Aedes aegypti, in the city of Monterrey, N.L., Mexico, showed a bimodal pattern. The first peak is lower and appeared at early June, while the second and higher one was observed in the second week of October. 1,419 female mosquitoes were caught in this study. Females with fresh red blood in the stomach were present in all the catches, gravid females (mature eggs in the ovaries) being more abundant than the non-gravid ones. The gravid females with red blood are the oldest of the vector population. Nevertheless, in October, 40 per cent of females had red blood and of these, 37 per cent were gravid. In relation to the biting rate, a 10 females/hour-man rate was recorded for the first peak and a 13.3 females/hour-man rate for the second one. There were 32 per cent of females involved in multiple feedings during the weekly catches. This incidence increases to 40 per cent in October. These rates were calculated on the basis of females with fresh blood in the stomach; from these the gravids and non-gravids have at least three and two multiple feedings, respectively. Finally the epidemiological importance of these multiple feedings on dengue transmission is discussed.

Aedes↗
PubMed1993

Seasonal abundance of dengue vectors in Manila, Republic of the Philippines.

The dengue vectors Aedes aegypti and Ae. albopictus were surveyed within the city of Manila from August 1985 to July 1987. Survey techniques included ovitraps, indoor resting collections, Fay traps, and larval surveys. Aedes aegypti was the principal container breeder within the residential areas, while Ae. albopictus predominated in cemeteries. The ovitrap was very effective in detecting the presence of Ae. aegypti, but not in measuring population changes during the year. Indoor resting and Fay traps show a low population of Ae. aegypti from February through May, during the dry season, and higher populations from June through September, during the rainy season. The most common indoor containers holding larvae were flower vases, while metal or glass containers were the most common outdoors. Dengue transmission appears to be closely related to rainfall, with cases increasing about 2 months following the onset of the rainy season.

Animals↗
PubMedDate not supplied

[The control of Aedes (Stegomyia) and related species involved in transmission of human arbovirus infections in tropical Africa (author's transl)].

In Africa, many Aedes mosquitos are involved in yellow fever and dengue transmission. Their control can be carried out either in a "prophylactic" way, when no disease occurs, or in a "curative" one, when virus is detected in the human community. In the first event, control is confounded with sanitation measures; in the second event, insecticidal control is needed against both larvae and adults. Larvae populations are destroyed by means of insecticidal deposits in the breeding-sites. Control of adults is achieved by thermal fogs or U.L.V. applications of organophosphorous compounds dispensed from ground or aerial generators. The insecticide susceptibility level of every Aedes populations involved in arbovirus transmission must be periodically determined with all the insecticides available.

Aedes↗