Showing papers on "Dengue fever published in 1968"

Dengue haemorrhagic fever: A pathological study

Abstract: The necropsy findings in 12 cases of dengue haemorrhagic fever are described. Interstitial pneumonitis was present in all 12, and protein-rich serous effusions were found in 9. In most patients deposits of fibrin could be demonstrated within blood vessel walls in the spleen, and less frequently in pancreas and lung. Although the pathogenesis of this fibrin deposition is unknown, it is believed to be a manifestation of increased vascular permeability. Paracentral areas of zonal necrosis were found in the liver in 4 cases; Councilman-like bodies were present in these 4, and intranuclear inclusion bodies were observed in 2 of them.

Dengue-virus recovery by direct and delayed plaques in LLC-MK2 cells.

Abstract: Summary A method for detecting and propagating dengue viruses in LLC-MK2 cells has been developed by direct plaquing and by fluid maintenance of inoculated cultures 7 to 14 days before plaquing (delayed plaquing). This procedure was used in support of studies of hemorrhagic fever and has resulted in the recovery of 69 dengue viruses, including all four serotypes. About half of these were detected by delayed plaques when direct plaques were not seen. Most of these dengue strains were inoculated simultaneously into mice and cell cultures. The direct and delayed plaque method was more sensitive and efficient than the use of suckling mice. Comparisons of the direct and delayed plaque method with other methods of recovery of dengue virus are discussed. Early in the study, occasional difficulty in preparing low-passage cell-culture seed virus of adequate titer was encountered. Consequently, the growth of dengue virus in LLC-MK2 cells was studied. Virus growth was synchronous and cyclic. In order to avoid inadvertent harvesting of virus during eclipse, live cells, rather than cell lysates, were passaged. This has resulted in consistent production of low-passage seed-virus suspensions.

An insular outbreak of dengue hemorrhagic fever. I. Epidemiologic observations.

Abstract: Summary Between 10 July and 23 October 1966 an epidemic of dengue hemorrhagic fever occurred on an island in the Gulf of Thailand. Fourteen cases of dengue-shock syndrome (with one death) and 20 of hemorrhagic-fever syndrome due to dengue occurred. An additional 65 cases of less severe dengue were seen. The 99 patients ranged in age from 1 to 15 years, with a median of 6.7 years; the female-to-male ratio was 55:44. The attack rate for the age group under 15 was 0.75% for the island as a whole, but reached 14% in one village. Dengue virus types 1, 2, or 3 were isolated from a total of 25 patients. Patients were categorized clinically and, independently, by serologic response to dengue. The syndromes of undifferentiated fever, dengue fever, and hemorrhagic fever were not found to be uniformly associated with dengue virus. Shock syndrome as defined was seen only in association with dengue and appeared to be a specific manifestation in the epidemiologic context cited. The median age in cases of mild illness was lower than that for either hemorrhagic fever or shock syndromes. The data presented are consistent with the hypothesis that the dengue-shock syndrome is due to an immunologic phenomenon associated with a second, or subsequent, dengue infection.

An epidemic of dengue-like illness in Jamaica-1963.

Abstract: Summary In June 1963 an outbreak of a dengue-like illness occurred in Jamaica. The only recorded dengue epidemic in Jamaica before that of 1963 had been in 1824, as mentioned in church records of causes of deaths. Over 450 primary inoculations of serum from acutely ill patients and from mosquitoes associated with them were made in animals and in tissue-cell cultures. A possible isolation was made in one cell culture inoculated with material from Aedes aegypti mosquitoes, as evidenced by interference studies. Otherwise, no isolation was made, although inoculated suckling mice gave signs of disease of the central nervous system. The characterization of the epidemic as “dengue-like” was based upon the clinical course of patients and upon serologic findings.

Application of Immunodiffusion Methods to the Antigenic Analysis of Dengue Viruses II. Immunoelectrophoresis

Abstract: Summary Six prototypes of dengue viruses, West Nile and Sindbis viruses were cross-reacted in a rather standard type of immunoelectrophoresis test against four rabbit anti-dengue sera representing two closely related pairs as determined by more conventional serology. By this test D-1 and TH-Sman were readily differentiated, each possessing three or four antigens not possessed by the other. One antigen was common to both and to all other dengue protoypes and West Nile virus. A similar differentiation was demonstrated between D-2 and TH-36 and all other viruses employed. One D-2 antiserum demonstrated what may be a subgroup specific dengue antigen shared by all dengues but not by West Nile. The method gives promise of improved differentiation of arboviruses within an antigenic group.

Cross Plaque Neutralization of Two Antigenically Closely Related Dengue Viruses (Type 2 New Guinea C and TH-36)

Abstract: SummaryDengue type 2, New Guinea “C” virus, from a case of classical dengue fever was compared with dengue TH-36, an agent antigenically closely related to it but isolated from a case of hemorrhagic fever. Cross neutralization tests by the plaque method were performed in duplicate with essentially duplicate results. These were plotted and the 50% serum end points were determined. Relative potencies for homologous and heterologous serum-virus combination were calculated. Significant differences in degrees of neutralization of the two viruses were obtained, the homologous serum and virus resulting in the highest percentage plaque reduction at every serum dilution in each experiment. It is concluded that these two viruses differ antigenically as demonstrated in relatively precise quantitative tests, confirming previous differences shown by complement fixation, immunodiffusion, and immunoelectrophoresis.