Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DENGUE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
PubMed2006

Early Dengue infection and outcome study (EDEN) - study design and preliminary findings.

INTRODUCTION: Dengue is a major public health problem in Singapore. Age-specific dengue morbidity rates are highest in the young adult population, unlike in many other Southeast Asian countries where dengue is mainly a paediatric disease. Hence, the World Health Organization (WHO) guidelines on dengue diagnosis and management which were developed using the paediatric experiences, may not be suitable for the management of adult dengue infections. MATERIALS AND METHODS: The Early DENgue (EDEN) infection and outcome study is a collaborative longitudinal study to investigate epidemiological, clinical, viral and host-specific features of early dengue-infected adults, in an effort to identify new early markers for prognostication. Patients presenting with early undifferentiated fever were included in the study. We carried out an interim analysis to look for early indicators of severe disease. RESULTS: During the period of this interim study analysis, 455 febrile patients were recruited. Of these, 133 were confirmed as acute dengue cases based on dengue-specific polymerase chain reaction (PCR) results. There were significant clinical and epidemiological differences between dengue and febrile non-dengue cases. Nine per cent of the dengue cases experienced persistent tiredness, drowsiness and loss of appetite beyond 3 weeks of illness. Quantitation of viral loads using the crossover (Ct) value of real-time RT-PCR correlated with the duration of symptoms. More than half of both primary and secondary dengue cases were hospitalised. There was no dengue-related mortality in this study. CONCLUSION: The duration of illness and prolonged symptom duration in 9% of the subjects indicate that the burden of dengue illness is substantially different from other non-dengue febrile illness in our study cohort. Our study also highlights the paucity of early prognostic markers for dengue fever in adults.

Adult↗
PubMed1994

Comparative sensitivity of laboratory methods to diagnose dengue virus infections at Husada Hospital, Jakarta.

Several methods are available for diagnosis of dengue virus infections including a new commercially available dengue blot IgG assay. We conducted a study to compare the sensitivity of the dengue blot with the conventional diagnostic methods. Serum samples from suspected dengue patients were collected for virus isolation and the following serological assays: the hemagglutination-inhibition assay, an IgM/IgG enzyme-linked immunosorbent assay, and the dengue blot. When suspected dengue samples were tested by all methods, viral isolation detected the fewest dengue infections (10.5%), while the IgM/IgG ELISA was the most successful (46.3%) in diagnosing dengue infections. In a specific comparison between the IgM/IgG ELISA and the dengue blot, the dengue blot had an overall sensitivity of 48.8%, with a specificity of 88.7%. When patients were classified by their serological response, the dengue blot had a sensitivity of only 1.7% in those patients with a primary or recent dengue infection, however in secondary infections, the sensitivity of the dengue blot improved to 93.5%. Testing convalescent samples from patients with primary infections, only slightly changed the sensitivity of the dengue blot. The diagnosis of dengue is needed rapidly by clinicians to insure prompt treatment of patients. The dengue blot provides a rapid and easily performed assay, especially sensitive in secondary dengue infections which are most common in hospitalized cases in Asia.

Antibodies, Viral↗
PubMed2006

Dengue-related deaths in Puerto Rico, 1992-1996: diagnosis and clinical alarm signals.

BACKGROUND: Dengue, although endemic in Puerto Rico, is often not mentioned in the death certificates of decedents with laboratory results positive for dengue. Because confirmatory results are usually not available during hospitalization, we examined the utility of 2 instruments for diagnosis on the basis of clinical findings: the definition of dengue hemorrhagic fever (DHF) and the publicized (but unevaluated) clinical alarm signals for impending dengue shock. METHODS: We studied data from all patients with laboratory test results positive for dengue who died (23 patients) and from the 8 patients whose death certificates listed dengue as a cause of death but whose laboratory test results were negative for dengue in Puerto Rico from 1992 through 1996. We examined hospital records to determine whether the clinical criteria for DHF were fulfilled and evaluated the incidence and timing of clinical alarm signals (intense, sustained abdominal pain; persistent vomiting; sudden change from fever to hypothermia; and marked restlessness or lethargy) and the hematocrit/hemoglobin ratio as an indicator of hemoconcentration. RESULTS: A similar proportion of patients with laboratory test results positive for dengue (18 [78%] of 23) and negative for dengue (6 [75%] of 8) fulfilled the criteria for DHF. Clinical alarm signals were found only among patients with laboratory test results positive for dengue and were usually noted on the day that the patient's condition deteriorated. The hematocrit/hemoglobin ratio identified 1 (6%) of 16 patients with dengue who had significant hemoconcentration. Important comorbidities were present in 16 (70%) of the patients with laboratory test results positive for dengue and in 4 (50%) of the patients with dengue-related deaths with laboratory test results negative for dengue. CONCLUSIONS: Dengue-related deaths in Puerto Rico often occur in patients with comorbidities. Among such patients, the DHF definition and the hematocrit/hemoglobin ratio were not useful in identifying patients with laboratory test results positive for dengue. In contrast, the clinical alarm signals for shock supported the dengue diagnosis and should alert clinicians to the severity of the disease.

Adolescent↗
PubMed2002

Dengue fever outbreaks in two villages of Dharmapuri district in Tamil Nadu.

BACKGROUND & OBJECTIVES: Dengue fever is an important public health problem in India. In recent years this disease has extended to rural areas also due to rapid urbanization. In Tamil Nadu, fever outbreaks were reported in two villages of Dharmapuri district during May and September 2001 with clinical symptoms suggestive of dengue fever. Epidemiological, virological and entomological investigations were carried out in these two villages to ascertain the etiology of the outbreaks. METHODS: Paired serum samples were collected from febrile patients clinically suspected to have dengue and were tested for the presence of IgM antibodies to dengue virus by MAC ELISA. Samples were also tested by Dengue Duo IgM/IgG rapid strip. Surveys of larval and adult Aedes mosquitoes were carried out before and after anti-larval and anti-adult measures were implemented. Female Ae. aegypti mosquitoes collected in Mampatti village were tested individually for the presence of dengue-2 viral antigen by indirect immunofluorescence assay (IIFA). In addition, two pools of female Ae. aegypti mosquitoes were tested for the presence of dengue viral antigen by ELISA and then subjected to Toxo-IFA system for demonstration of dengue virus. RESULTS: A total of 124 and 267 fever cases with clinical symptoms and signs suggestive of dengue were reported in Kadumuchandiram and Mampatti villages of Dharmapuri district, respectively. Serodiagnosis revealed that 13 of 31 and 14 of 52 patients tested were positive for dengue-2 virus by MAC ELISA in Kadumuchandiram and Mampatti villages respectively. Dengue Duo rapid strip test also detected 14 (of 31 tested) patients positive for dengue virus specific IgM antibodies in Kadumuchandiram village and 8 (of 12 tested) in Mampatti village. Application of temephos and fogging with pyrethrum 2 per cent extract were found to be effective against immatures and adults respectively. Both the pools of Ae. aegypti tested for the presence of dengue viral antigen were positive by ELISA and one mosquito (tested individually) was positive by IIFA. Supernatants of two pools were found to be positive for dengue-2 virus by Toxo-IFA. INTERPRETATION & CONCLUSION: Virological and serological investigations confirmed that the outbreaks of fever were due to dengue virus infection. High breeding of Ae. aegypti in the study villages, detection of dengue-2 viral antigen and isolation of dengue-2 virus in Ae. aegypti mosquitoes confirmed the etiology.

Dengue↗
PubMedDate not supplied

[Significance of IgM titration by an immunoenzyme technic for the serodiagnosis and epidemiological surveillance of dengue in French Polynesia].

The usefulness of IgM antibody capture enzyme-linked immunosorbent assay (ELISA-IgM) for the diagnosis of dengue was studied using several groups of sera. An attempt was made to detect IgM against each dengue serotype. Of 76 paired sera from patients with dengue type 4 infection, the diagnosis was confirmed by ELISA-IgM in 74: in 47 out of 49 primary dengue infections and in all 27 secondary dengue infections. It was possible to detect IgM in 15 of the acute sera of primary infections and in 16 of the acute sera of secondary infections. In 20 patients from whom only single serum with high haemagglutination-inhibition titre (greater than or equal to 640) was available, 18 were found positive for dengue IgM. Dengue infection was also confirmed in 10 patients with dengue type 1 and in 10 patients with dengue type 2. IgM was detected in 1 of the acute sera of patients with either dengue type 1 or dengue type 2 infection. In all cases in which IgM was detected, a positive response was obtained for the homologous antigen. ELISA-IgM on sequential serum samples from 7 proven cases of dengue type 4 revealed that antibody titres greater than or equal to 400 are reached early in the second week of the illness and persist for 60 days or more at a low level (titre less than 400). An attempt was made to obtain a type-specific presumptive diagnosis by analysing the relative titre against each of the 4 antigens. It was possible to make a diagnosis of dengue type 4 in 85% and 52% of IgM-positive responses in primary and secondary infections (p less than 0.01), respectively, using paired sera from patients with known dengue type 4 infection. ELISA-IgM was shown to be of interest in the diagnosis and surveillance of dengue in French Polynesia where dengue viruses are, presently, the only known flavivirus.

Antibodies, Viral↗
PubMed2002

Dengue.

PURPOSE OF REVIEW: Because efforts to control dengue are flagging, this review focuses on the mechanisms underlying severe disease and on treatment options, good and bad. RECENT FINDINGS: The year 2001 witnessed unprecedented global dengue epidemic activity in the American hemisphere, the Pacific islands and continental Asia. Early diagnosis of dengue is important but what is the value and appropriate use of the tourniquet test? A negative test does not rule out dengue infection, a positive test should be followed by close surveillance for early signs of dengue hemorrhagic fever. Low platelet counts do not predict clinically significant bleeding in dengue. It follows that platelet or blood transfusions should not be administered based upon platelet count alone. Dengue hemorrhagic fever or dengue shock syndrome cases frequently have compensated consumptive coagulopathy that seldom requires treatment. Bleeding is most likely caused by activated platelets resulting from damaged capillary endothelium. Dengue hemorrhagic fever and dengue shock syndrome can be safely treated with just normal saline. Colloids should be immediately given to children presenting with a pulse pressure at or below 10 mmHg. Human leukocyte antigen alleles correlate with both protection and susceptibility to dengue hemorrhagic fever and dengue shock syndrome; studies in Haiti suggest that blacks have a gene providing nearly complete protection against severe dengue illness. SUMMARY: The role that antibodies play in protecting and enhancing dengue infections has been largely ignored. Such studies require definitive knowledge of what cells are infected in human dengue and an understanding of all the early antibody-accessible steps of infection of these target cells.

Dengue↗
PubMed1999

A prospective seroepidemiologic study on dengue in children four to nine years of age in Yogyakarta, Indonesia I. studies in 1995-1996.

A prospective study on dengue (DEN) viruses was initiated in October 1995 in Gondokusuman kecamatan, Yogyakarta, Indonesia. This report presents data from the first year of the study. The studied cohort included all children 4-9 years of age living in the kecamatan. Blood samples for serology were collected from 1,837 children in October 1995 and again in October 1996. Blood samples for virus isolation and serology were collected from cohort children who were seen in municipal health clinics with febrile syndromes or admitted to hospitals with a provisional diagnosis of dengue hemorrhagic fever. Dengue serotype antibody prevalence and 1995-1996 infection rates were calculated using a single dilution (1:60) 70% plaque reduction endpoint neutralization test. Prevalence of dengue antibody at the beginning of the study was DEN 1 = 12%, DEN 2 = 16%, DEN 3 = 2%, DEN 4 = 4%, and two or more dengue infections = 22%. Total dengue antibody prevalence increased from 38% in 4-year-old children to 69% in 9-year-old children. During the observation period, primary dengue infection rates were DEN 1 = 4.8%, DEN 2 = 7.7%, DEN 3 = 4.2%, and DEN 4 = 3.4%, while two or more dengue infections occurred in 6.7% of the study population. The secondary dengue infection rate was 19.0%. From febrile cases, all four dengue viruses were isolated with DEN 3 predominating. Seven children were hospitalized, including one fatal case with a hospital diagnosis of dengue shock syndrome. Based upon presence of antibody in the initial cohort bleeding and the serologic response both weeks and several months following illness, all had secondary dengue infections. Neutralizing antibody patterns in the initial cohort bleeding and in late convalescent serum samples permitted recognition of dengue infection sequence in five patients: DEN 2-DEN 1 (3), DEN 2-DEN 4 (1), DEN 1-DEN 3 (1), and none in the sequence DEN 1-DEN 2. In the total cohort 6.5% of the observed secondary infections were of the sequence DEN 2-DEN 1, while 4.9% were DEN 1-DEN 2, a highly pathogenic sequence in previous studies. Reduced pathogenic expression of secondary DEN 2 with enhanced pathogenic expression of secondary DEN 1 infections was an unexpected finding. Further studies will be required to understand the respective contributions to pathogenicity of antibody from initial dengue infections versus the biological attributes of the second infecting dengue viruses.

Age Distribution↗
PubMed1977

Dengue virus infections in Nigeria: a survey for antibodies in monkeys and humans.

A retrospective serological survey for dengue immunity was conducted in Nigeria to determine the prevalence of infection in man and non-human primates. Preliminary haemagglutination-inhibition (HI) tests revealed that 63% of persons tested had HI antibodies against one or more of the following flaviviruses: dengue type 1, yellow fever, West Nile and Wesselsbron. Parallel HI and neutralization (N) tests on 179 human sera showed that six of 20 sera (30%) negative for flavivirus HI antibody contained dengue N antibody. This finding emphasized the advantage of the N test over HI in screening for dengue virus immunity. Neutralization tests performed on 1,816 human sera from different geographical locations in Nigeria showed that 45% of Nigerians were immune to dengue type 2 virus. The percentage of immunity in adults aged 20 years and older (51%) was significantly higher than in children (37%) (P less than 0-01). In all four ecological zones sampled, the highest percentage of dengue N antibody was observed in the derived Savannah zone (63%) followed by the rain forest zone (42%). The Southern Guinea savannah and plateau zones had lower percentages of dengue-immune persons. There was a higher prevalence of antibodies in urban (48%) than in rural communities (37%). Tests on dengue-immune sera showed that 35% of such sera contained N antibodies to dengue only or to dengue and one other virus. Therefore, dengue immunity cannot be explained by heterologous cross reactions within the flavivirus group. In addition, evidence of dengue infection was found in monkeys and galagos. 48% of monkeys and 25% of galagos contained dengue N antibody. The presence of specific dengue N antibodies in a few sera suggests that the occurrence of a forest cycle of dengue is possible in Nigeria.

Animals↗
PubMed2002

Spatial and temporal circulation of dengue virus serotypes: a prospective study of primary school children in Kamphaeng Phet, Thailand.

Dengue virus occurs as four distinct serotypes, each of which causes epidemics throughout the tropical and subtropical regions of the world. Few studies have examined co-circulation of multiple dengue virus serotypes in a well-defined cohort population over time and their capacity to produce severe dengue disease. In this paper, the authors report the details and findings of the first 3 years (1998-2000) of an ongoing prospective study of dengue virus transmission and disease severity in a cohort of children in northern Thailand. A total of 108 dengue virus isolates were obtained from 167 acute dengue virus infections; 23% were DEN-1, 35% were DEN-2, 41% were DEN-3, and 1% were DEN-4. Despite the proximity of the schools, there was marked spatial and temporal clustering of transmission of each dengue serotype. Serotype-specific antibody levels prior to the dengue transmission season were not predictive of the incidence of dengue virus infections or the predominant serotype transmitted at individual schools. All dengue serotypes produced severe dengue illness, although DEN-3 produced more severe symptoms than the other dengue serotypes. The authors' findings emphasize the complexity of dengue serotype-specific virus transmission and severe dengue disease and have important implications for dengue control and vaccine development.

Acute Disease↗
PubMed1984

Lysis of dengue virus-infected cells by natural cell-mediated cytotoxicity and antibody-dependent cell-mediated cytotoxicity.

Peripheral blood mononuclear cells (PBMC) from humans without antibodies to dengue 2 virus lysed dengue 2 virus-infected Raji cells to a significantly greater degree than uninfected Raji cells. The addition of mouse anti-dengue antibody increased the lysis of dengue-infected Raji cells by PBMC. Dengue 2 immune human sera also increased lysis of dengue-infected Raji cells by PBMC. These results indicate that both PBMC-mediated cytotoxicity and antibody-dependent cell-mediated cytotoxicity (ADCC) can cause significant lysis of dengue-infected Raji cells. The lysis of infected Raji cells in the ADCC assay correlated with the dilution of dengue-specific antibody which was added, indicating the dengue virus specificity of the lysis of dengue virus-infected Raji cells. Alpha interferon (IFN alpha) was detected in the culture supernatant of PBMC and dengue-infected Raji cells. However, enhanced lysis of dengue-infected Raji cells by PBMC may not be due to the IFN produced, because neutralization of all IFN activity with anti-IFN alpha antibody did not decrease the lysis of dengue-infected cells, and effector cells pretreated with exogenous IFN alpha also lysed dengue-infected cells to a greater degree than uninfected cells. The effector cells responsible for lysis of dengue virus-infected Raji cells in the natural killer and ADCC assays were analyzed. Nonadherent PBMC caused more lysis than did adherent cells. Characterization of nonadherent cells with monoclonal antibodies showed that the predominant responsible effector cells were contained in OKM1+ and OKT3- fraction in the natural killer and ADCC assays.

Animals↗
PubMed2006

Patterns of disease in Sri Lankan dengue patients.

BACKGROUND: Dengue is the most important mosquito borne viral infection in the world. Nearly 90% of infections occur in children. At present, prospective information on clinical and laboratory findings in South Asian children with dengue is generally lacking. AIM: To describe patterns of clinical disease in a cohort of children hospitalised with dengue during a major dengue epidemic in Sri Lanka. RESULTS: A total of 104 children were studied during a three month period. Eighteen had dengue fever (DF) and 86 had dengue haemorrhagic fever (DHF). Of those with DHF, 34, 23, 27, and 2 had DHF grade I, II, III, and IV respectively. Based on dengue serology testing, 13 of the DF patients had a primary infection and 5 had secondary dengue infections. In contrast, 68 of the children with DHF had secondary and 18 had primary dengue infections. Oral candidiasis was seen in 19 children. The odds ratio for children with secondary dengue infection to develop DHF was 9.8 (95% CI 3.1 to 31.2). CONCLUSION: Studies on patterns of paediatric dengue disease in different regions should help clinicians and health administrators make more informed and evidence based health planning decisions. It should also help towards mapping out dengue trends on a global scale. Oral candidiasis has not been previously documented in children suffering with acute dengue in Sri Lanka or elsewhere. Studying underlying reasons for this manifestation during future dengue epidemics may provide useful leads in understanding overall dengue pathogenesis.

Acute Disease↗
PubMed2001

Virologic and serologic surveillance for dengue fever in Jeddah, Saudi Arabia, 1994-1999.

Dengue fever infection was first documented in Jeddah, Saudi Arabia, by virus isolation of dengue type 2 virus in 1994 at the virology laboratory of Dr. Soliman Fakeeh Hospital. Dengue virus surveillance was established after that time. Blood samples were collected from 985 patients (710 male patients and 275 female patients) with suspected cases of dengue from February 1994 to December 1999. Dengue virus isolates were obtained in 207 patients (21%; 162 male patients and 45 female patients). Dengue type 2 was the predominant serotype (138 of 207 isolates, 66.7%), followed by dengue type 1 with (56 of 207 isolates, 27%) and dengue type 3 (13 of 207 isolates, 6.3%). The largest number of isolates (186 of 207 isolates, 90%) was in 1994, a year during which there was a dengue epidemic. In the next 5 years, 1995-1999, only 21 isolates (10%) were isolated. Immunoglobulin M capture enzyme-linked immunosorbent assay was positive in 160 acute samples; 52 of them were from virus culture-positive cases and 108 (11%) from culture-negative cases. The total number of cases diagnosed by both methods was 315 (32%). The prevalence of dengue immunoglobulin G antibodies, as assessed on the basis of immunofluorescent assay, hemagglutination inhibition titers > or = 1/20, or both, in the acute samples was 314 (32%) of 985, indicating past Flavivirus infection. Two patients died, one man with dengue hemorrhagic fever and one woman with dengue shock syndrome. Both fatal dengue cases were due to infection with type 2 virus. All other cases were simple dengue fever. To our knowledge, this is the first report confirming the circulation of 3 dengue serotypes in Jeddah.

Adolescent↗
PubMed1986

Multisite monoclonal immunoassay for dengue viruses: detection of viraemic human sera and interference by heterologous antibody.

A monoclonal radioimmunoassay (RIA) was developed for detection of dengue virus in infected cell culture fluids and blood samples from dengue patients. Antibodies used to construct the RIA were selected on the basis of high binding avidity, the demonstration of synergism in competitive binding assays and empirical trials with different antibody combinations. Optimal binding of all four dengue virus serotypes was achieved by use of a flavivirus group-reactive and a dengue virus complex-reactive antibody as radiolabelled probe. A 'simultaneous sandwich' format and prolonged (18 h) incubation at 37 degrees C yielded optimal results. The limit of sensitivity of the RIA for detection of dengue type 2 virus was 2.7 log10 mosquito 50% infectious doses (MID50). The assay was tenfold more sensitive for dengue type 2 than for dengue types 1 and 3 viruses and 100-fold more sensitive than for dengue type 4 virus. Specificity, assessed using over 500 disease control human sera, was increased by addition of monoclonal anti-tetanus blocking antibodies, resulting in a false positive rate of only 0.2%. Heterologous dengue virus antibodies were shown to inhibit the RIA in assays performed with artificial immune complexes. Acute phase human sera containing 10(4.2) to 10(7.6) MID50 but no detectable antigen by RIA, were also shown to inhibit binding of the homologous dengue virus serotype; this effect was attributed to heterologous antibody from a prior infection. Among 116 viraemic sera from dengue patients, the RIA was positive in 43 to 47% of patients with dengue type 1, 2 or 3 infections but in only 10% of the dengue type 4 cases. Virus was more frequently detected in cases of primary infection (54%) than in cases of superinfection (16%). Despite the limitations imposed by immunological interference, the antigen capture RIA appears useful as a rapid diagnostic technique for dengue surveillance.

Aedes↗
PubMed1996

[Dengue in French Guiana. History and present status].

The evolution of dengue in French Guiana has the same trend as in most tropical American countries, with emergence of dengue hemorrhagic fever (DHF) and endemicity of the disease. During the 1940's, several dengue-like outbreaks were reported from French Guiana. Then, the only dengue vector, Aedes aegypti, was eradicated between 1950 and 1963, when it started to reinfest the country. By the end of the 1960's, new dengue epidemics with serological confirmation were described. After 1970, the first dengue strains were isolated, firstly dengue-2 strains, then dengue-1 and dengue-4 strains. Between 1970 and 1990, several dengue outbreaks struck French Guiana with 2 to 6 years intervals. In July 1991, started the first DHF outbreak in French Guiana which spread in all the most important towns until October 1992. About 3,000 cases were reported, that is almost 3% of the population, from which about 1/3 had serological confirmation; more than 300 people were hospitalized and some 80 with hemorrhages. Finally 6 deaths were reported, 5 of which had hemorrhages but could not be included into DHF cases according to WHO criteria. The dengue-2 strain responsible for this outbreak is close to the Jamaïcan topotype known to be particularly virulent. Since the beginning of 1993 and actually, dengue is still circulating in French Guiana, but at low level and dengue-1 and dengue-4 strains are occasionally isolated.

Dengue↗
PubMed2006

Post-infectious fatigue syndrome in dengue infection.

BACKGROUND: Although the acute manifestations of dengue are well known, few studies have assessed the long-term consequences of dengue infection. We prospectively studied the incidence and factors associated with fatigue in a cohort of patients following dengue infection. METHODS: We included patients with serologically confirmed dengue infection admitted to the National University Hospital, Singapore, during a dengue outbreak from October-November 2005. The severity of dengue was graded as dengue fever, dengue haemorrhagic fever and dengue shock syndrome. A follow-up telephone interview was performed two months following hospital discharge, where a Fatigue Questionnaire was administered. The presence of significant fatigue was considered as the main outcome measure. Significance was assessed at P<0.05. RESULTS: One hundred twenty-seven patients, 71 (55.9%) males and 56 (44.1%) females, of mean age 36.06 years (range, 16-70; S.D., 13.722), participated in this study. Twenty-five (19.7%) patients had dengue haemorrhagic fever and the remaining 102 (80.3%) had dengue fever. In multivariate analysis, increased age, female sex, the presence of chills, and the absence of rashes were significantly associated with the development of fatigue post-dengue infection. There was no significant association between fatigue and dengue severity. CONCLUSIONS: This observation represents the first systematic evidence that dengue can result in clinical disease beyond the acute phases of infection. Host factors, such as age and sex may be important in the pathogenesis of this clinical entity.

Adolescent↗
PubMed2002

Knowledge and use of prevention measures related to dengue in northern Thailand.

OBJECTIVE: To determine the frequency and determinants of knowledge of dengue infection in three sites in northern Thailand, and to compare prevention measures of people with and without knowledge of dengue. METHODS: In May 2001 we conducted an epidemiological survey among 1650 persons living in three areas in northern Thailand. Knowledge of dengue and the use of prevention measures were measured by means of a structured questionnaire. Differences in knowledge of dengue and the use of prevention measures between risk groups were calculated by chi-square test. Logistic regression was used to identify determinants of knowledge. RESULTS: Of the 1650 persons, 67% had knowledge of dengue. Fever (81%) and rash (77%) were the most frequently mentioned symptoms. Persons with knowledge of dengue reported a significantly higher use of prevention measures than persons without knowledge of dengue. In multivariate analyses, knowledge of dengue significantly differed by age, sex, occupation and site (P < 0.05). Younger people knew more about dengue than older persons: adjusted odds ratio (aOR) of 6.75 [95% confidence interval (CI): 4.32-10.6] for the 15-29 age group compared with people aged 60 and older. In comparison with farmers (reference group), knowledge of dengue was significantly higher among students (aOR: 10.6, 95% CI: 4.27-26.4), but lower among housewives or unemployed persons (aOR: 0.44, 95% CI: 0.31-0.64). CONCLUSION: The overall knowledge of dengue was high, but housewives, unemployed and old persons had relatively little knowledge of dengue. Therefore, these groups may need special attention in future dengue education programmes. Persons with knowledge of the disease more frequently reported the use of preventive measures, indicating the value of education programmes as a tool in dengue prevention.

Adolescent↗
PubMed1999

Analysis of murine CD8(+) T-cell clones specific for the Dengue virus NS3 protein: flavivirus cross-reactivity and influence of infecting serotype.

Serotype-cross-reactive dengue virus-specific cytotoxic T lymphocytes (CTL) induced during a primary dengue virus infection are thought to play a role in the immunopathogenesis of dengue hemorrhagic fever (DHF) during a secondary dengue virus infection. Although there is no animal model of DHF, we previously reported that murine dengue virus-specific CTL responses are qualitatively similar to human dengue virus-specific CTL responses. We used BALB/c mice to study the specificity of the CTL response to an immunodominant epitope on the dengue virus NS3 protein. We mapped the minimal H-2Kd-restricted CTL epitope to residues 298 to 306 of the dengue type 2 virus NS3 protein. In short-term T-cell lines and clones, the predominant CD8(+) CTL to this epitope in mice immunized with dengue type 2 virus or vaccinia virus expressing the dengue type 4 virus NS3 protein were cross-reactive with dengue type 2 or type 4 virus, while broadly serotype-cross-reactive CTL were a minority population. In dengue type 3 virus-immunized mice, the predominant CTL response to this epitope was broadly serotype cross-reactive. All of the dengue virus-specific CTL clones studied also recognized the homologous NS3 sequences of one or more closely related flaviviruses, such as Kunjin virus. The critical contact residues for the CTL clones with different specificities were mapped with peptides having single amino acid substitutions. These data demonstrate that primary dengue virus infection induces a complex population of flavivirus-cross-reactive NS3-specific CTL clones in mice and suggest that CTL responses are influenced by the viral serotype. These findings suggest an additional mechanism by which the order of sequential flavivirus infections may influence disease manifestations.

Amino Acid Sequence↗
PubMed2003

Antibodies from dengue patient sera cross-react with endothelial cells and induce damage.

Dengue virus infection causes a wide range of diseases from the mild febrile illness dengue fever to the life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Vascular leakage and hemorrhagic syndrome are the clinical features associated with dengue infection, yet the mechanisms remain unclear. In this study, the cross-reactivity of dengue patient sera with endothelial cells was demonstrated. There were higher percentages of endothelial cells reactive with dengue hemorrhagic fever/dengue shock syndrome patient sera than those with dengue fever patient sera. The percentages of endothelial cells reactive with patient serum IgM were higher than those with IgG. Further studies showed that the endothelial cell binding activity was inhibited by pretreatment with dengue virus nonstructural protein 1 (NS1). The antibodies against NS1 produced after dengue virus infection may, at least in part, account for the cross-reactivity of patient sera with endothelial cells. Furthermore, dengue patient sera induced endothelial cell apoptosis via a caspase-dependent pathway that was also inhibited by NS1 pretreatment. In addition to apoptosis, patient sera caused cell lysis in the presence of complement, and DHF/DSS patient sera showed higher percentages of cytotoxicity than dengue fever patient sera. Thus, the generation of cross-reactive autoantibodies against endothelial cells would lead to their dysfunction, which may play a role in the pathogenesis of dengue virus infection.

Antibodies, Viral↗