UNUSUAL ANTIGENIC AND GENETIC-CHARACTERISTICS OF HUMAN RESPIRATORY SYNCYTIAL VIRUSES ISOLATED IN CUBA

The G protein of 23 strains of human respiratory syncytial virus isola ted in Havana, Cuba, between October 1994 and January 1995 was analyze d at the antigenic and genetic level. All viruses reacted,vith 10 of 1 1 antibodies specific for the Long strain. Moreover, the G protein gen e of the Cuban isolates had only five nucleotide differences from the sequence of the Long gene. The homogeneity of the Cuban isolates and t heir resemblance to an ancient strain, such as Long, are at odds with previous findings for viruses isolated in countries with a temperate c limate and different socioeconomic status. The G proteins of three of four other viruses isolated in Havana 2 years later (1996) were also i dentical to those of the 1994-to-1995 isolates, and the fourth virus h ad a single extra nucleotide difference. This, again, is unusual, sinc e no identical viruses had been isolated in different epidemics previo usly. The singular characteristics of the Cuban isolates reported here are discussed in terms of the epidemiological, climatic, and socioeco nomic characteristics of Cuba.