Showing papers on "Dengue virus published in 1969"

Dengue and chikungunya virus infection in man in Thailand, 1962-1964. IV. Epidemiologic studies in the Bangkok metropolitan area.

Abstract: An attempt at a comprehensive measurement of illness documented by physicians and infection in man caused by dengue and chikungunya viruses was made in Bangkok and Thonburi during all or portions of 1962–1964. Inpatient data were collected directly from all metropolitan hospitals. Outpatients were studied only at Children's Hospital. In 1962, a seroepidemiologic study of arbovirus infection was made in 7,093 Bangkok households in 19 separate areas, from five of which mosquitoes were collected for enumeration and attempts to isolate virus. During the study, 10,194 patients with hemorrhagic fever were admitted to Bangkok hospitals, and 559 died. At least 80% of these cases were caused by dengue virus. In 1962 alone, it was estimated that between 181,000 and 287,000 dengue illnesses and 44,000 to 70,000 chikungunya illnesses were seen by physicians in outpatient children. Agespecific hospitalization rates peaked at less than 1 year and again at 3 or 4 years, few cases occurring after the age of 15. Hospitalizations were rare in infants during the first 3 months of life; rates then rose abruptly, peaking at 8 months then declining markedly. Hospitalization rates for girls over the age of 1 were consistently higher than for boys. Dengue- and chikungunya-infection rates measured in 1,887 persons bled before and after the rainy season in 1962 were 41% and 31%, respectively. Hospitalization rates varied directly with dengue-virus infection rates but not with income or ethnic group. Hospitalizations occurred within families at almost four times the expected rate. Disease progressed throughout the city and within study areas in a “brush-fire” manner. In contrast to the observations of others, we isolated dengue and chikungunya virus almost exclusively from Aedes aegypti. Although Culex tritaeniorhynchus and Culex gelidus were numerous in light-trap collections, they were rarely attracted to man. These observations suggest a low level of anthropophilia in these species in Thailand and the possibility of a biological barrier to transmission of arboviruses by them to man.

The 1964 chikungunya epidemic at vellore, South India, including observations on concurrent dengue

Abstract: Virological and serological studies on 477 fever patients seen at the Christian Medical College Hospital, Vellore, South India, from mid-August through December, 1964, indicated that 274 patients suffered infection with chikungunya virus alone (virus recovered from 224), 14 with both chikungunya and dengue viruses, either simultaneously (8) or sequentially (6), and 6 with dengue virus only. Arthralgia was the most prominent clinical feature in chikungunya infections; haemorrhagic manifestations were rare and uniformly mild. Myalgia was the chief complaint of dengue patients. Chikungunya virus was readily isolated only from human serum collected during the first 2 days of illness; viraemia levels were found to drop rapidly after the 2nd day, although viraemia remained detectable until after the 5th day. Serum virus titres were high, in some instances exceeding 6.0 log LD50 per 0.02 ml., and 2 high-titred sera exhibited viral haemagglutination when extracted with acetone. The virus was detected in human serum in the presence of low levels of haemagglutination-inhibiting (HI) and neutralizing antibody. HI chikungunya antibody appeared during the 4th to 6th days after onset of fever and reached a peak during the 2nd week; complement-fixing (CF) antibody appeared later and reached a peak in the 3rd month. By the 9th month, both HI and CF antibody had declined 4-fold in titre. Chikungunya virus was not recognized as being active in South India before the 1964 epidemic, but subsequent study of pre-epidemic survey sera suggests that the virus was present in the area during the 1930's. No case of chikungunya infection has been detected at Vellore since the end of 1964.

Recurrence of epidemic dengue hemorrhagic fever in an insular setting.

Abstract: Epidemic dengue hemorrhagic fever recurred in 1967 on an island in the Gulf of Thailand. All cases seen were categorized by clinical syndrome as shock, hemorrhagic fever, dengue fever, or undifferentiated fever. Paired serum samples were examined for HI, CF, or neutralizing antibody, or both, to dengue, for classification, where possible, into primary or secondary antibody response. There were 68 cases of dengue or probable dengue seen. Among them were five cases of shock syndrome and 10 of hemorrhagic fever; in none of these 15 was there a primary type of antibody response. Dengue virus type 4 was recovered from seven cases in man, while dengue types 1, 2, and 3 had been reported there previously. Cases occurred from mid-July through November; most patients were between 2 and 10 years of age; no sex selection was seen. Areas of the island that had high attack rates in 1966 were relatively spared in 1967, possibly indicating some degree of long-lasting cross-immunity. These observations continue to support the second-infection hypothesis.

Molecular epidemiology and phylogenetic analysis of Dengue virus type-1 and 2 isolated in Malaysia.

Abstract: Objective Detection of different serotypes of dengue virus and provide information on origin, distribution and genotype of the virus. Methods Dengue virus serotypes identified as DEN-1 and DEN-2 were amplified and sequenced with E gene. The consensus sequences were aligned with references E gene sequences of globally available GenBank. Phylogenetic analysis was performed using Neighbor-joining and Kimura 2-parameter model to construct phylogenetic tree. Results A total of 53 dengue virus isolates were positive, of which 38 (71.7%) were DENV-1 and 15 (28.3%) were DENV-2. Phylogenetic tree of DENV-1 and DENV-2 showed that the isolates were clustered in genotype I and cosmopolitan genotype, respectively considered the predominant genotypes in Southeast Asian countries. The molecular epidemiology genotype I DENV-1 and cosmopolitan genotype DENV-2 have been co-circulating in Klang Valley areas, Malaysia without shifting of genotype. Conclusion The study reveals that DENV-1 and DENV-2 have been circulating in Malaysia. The isolates are clustered in genotype 1 and cosmopolitian genotype, respectively. The study results would help in planning for prevention and control of dengue virus in Malaysia.

The effect of hyperthermia on dengue virus infection of mice.

Abstract: SummaryPassively induced hyperthermia significantly delayed or prevented lethal CNS infections of mice produced by a line of type 1 dengue virus with a history of 33 serial mouse brain passages (MP-33) but not one with a history of 125 passages (MP-125). This effect was not due to any enhancement of interferon production in the brain but was the result of a reduced rate of viral multiplication. Permanent recovery from MP-33 infection in hyperthermic animals was correlated with the appearance of the immune response.

Seroprevalence of acute dengue in a Malaysian tertiary medical centre.

Abstract: OBJECTIVES The aims of this study were to determine the seroprevalence of acute dengue in Universiti Kebangsaan Malaysia (UKM) Medical Centre and its correlation with selected haematological and biochemical parameters. METHODS This cross-sectional study was conducted from January to June 2015. A patient was serologically diagnosed with acute dengue if the dengue virus IgG, IgM or NS-1 antigen was reactive. RESULTS Out of 1,774 patients suspected to have acute dengue, 1,153 were serologically diagnosed with the infection, resulting in a seroprevalence of 64.9%. Dengue-positive patients had a lower mean platelet count (89 × 10(9)/L) compared to the dengue-negative patients (171 × 10(9)/L) (p<0.0001). The mean total white cell count was also lower in the dengue-positive cases (4.7 × 10(9)/L vs. 7.2 × 10(9)/L; p<0.0001). The mean haematocrit was higher in patients with acute dengue (42.5% vs. 40.0%; p<0.0001). Likewise, the serum alanine transaminase level was also higher in patients with acute dengue (108 U/L vs. 54 U/L; p<0.0001). CONCLUSIONS Dengue is very prevalent in UKM Medical Centre as most patients suspected to have acute dengue had serological evidence of the infection. The platelet count was the single most likely parameter to be abnormal (i.e. low) in patients with acute dengue.