Recurrent dengue fever in Jamaica - abstract

ABSTRACT

From clinical and serological evidence, dengue is believed to be endemic in Jamaica. However, no positive confirmation had been made of this fact because the virus had not been isolated and St. Louis Encephalitis virus, a close serlogical relative of dengue, is known to be present in the island. Certain communities in the island were known to have an incidence of dengue antibody as high as 60-70 percent. Nevertheless, during the 1963 outbreak these communities suffered a high incidence of infection second only to the Kingston and St. Andrew area. Again in 1968, the Kingston and St. Andrew population was heavily affected and in some instances persons complained of having dengue twice within months. Most of our clinical cases were adults. Between January, 1968 and January, 1969, a total of 679 cases was reported. 112 of 175 tested were proved serologically to be due to recent infection. Using challenge virus resistance technique in AGMK and BSC-1 cells with echo 9 and polio 1 as challenge viruses, 20 agents were isolated. Nineteen of these were from human sera and one from a pool of Aedes aegypti mosquitoes. 31 human sera were inoculated into one-day Swiss white mice. On 14 occasions symptoms indicative of viral infection were seen. Some of our isolates have been confirmed by plaque techniques in LLC-MK2 and PS continuous pig kidney cell lines. The rapid development of high serological titres seen in individuals with classical dengue symptoms suggests a secondary immune response. This is in contrast to cases in which dengue symptoms were associated with moderate conversions, presumably primary infections. In two cases virus was isolated from specimens with coexisting dengue antibody. During the earlier part of 1968 typical symptoms were fever, joint and retro-orbital pain with occasional rash. During the latter half of the year nausea and severe abdominal distress became prominent while the rash became more frequent and total, appearing even on the palms of the hands and soles of the feet. The significance of these observations is not clearly understood, but they could bear comparison with situations reported from the Far East. There, repeated infections have resulted in extremely severe "Dengue symptoms", haemorrhage, shock and death (AU)