Search PubMed⌕ Search

Biomedical subjects

G E Sather

Publications and source records attributed to G E Sather.

At least 37 records · Page 2Linked to original sources

Dengue outbreaks in Guánica-Ensenada and Villalba, Puerto Rico, 1972-1973.

Epidemics of dengue fever occurring in Puerto Rico in 1963 to 1964 and 1969 were caused by dengue-3 and dengue-2 (DN-2) viruses, respectively, but endemic dengue transmission has never been documented on the Island. Since the 1969 epidemic, a surveillance system has detected DN-2 activity on the Island during each of the years 1970 through 1973, which suggests endemic persistence of the virus. This report describes the investigation of localized outbreaks of DN-2 in Guanica-Ensenada (1972) and Villalba (1973), and presents epidemiological, serological, and virological data from the outbreaks. Analysis of geographic distribution of dengue activity in Puerto Rico in recent years indicates that the DN-2 transmission in 1970 to 1973 may represent a long tail-off of the 1969 epidemic rather than the emergence of a truly endemic situation.

Adolescent↗

Possible evidence for interference with Venezuelan equine encephalitis virus vaccination of equines by pre-existing antibody to Eastern or Western Equine encephalitis virus, or both.

During 1971, an epizootic of Venezuelan equine encephalitis (VEE) reached the United States. Laboratory tests were performed on a large number of sick, healthy, unvaccinated, and vaccinated horses. Neutralization (N) tests in cell cultures revealed that 153 of 193 (79.3%) equines outside the state of Texas and 175 of 204 (85.8%) within Texas (82.6% overall) had detectable N antibody to VEE virus a week or more after vaccination. Twenty-six of 40 (65%) non-Texas equines and 18 of 29 (62%) Texas equines which had no detectable antibody against VEE virus a week or more after vaccination had N antibody against Eastern equine encephalitis (EEE) or Western equine encephalitis (WEE) virus or both, whereas only 50 of 153 (32.7%) non-Texas equines and 82 of 175 (46.9%) Texas equines with demonstrable N antibody against VEE also had N antibody against EEE and/or WEE virus. In vaccinated equines, significant negative correlations were found between the occurrence of antibody to VEE and antibody to EEE and/or WEE virus. These findings support the hypothesis that pre-existing antibody to EEE and/or WEE virus may modify or interfere with infection by VEE virus. The epizoologic significance of this possibility is discussed briefly.

Animals↗

Effect of urea on the hemagglutinating and complement-fixing antigens of type 2 Dengue virus.

Sephadex G-200 filtration was used for fractionating dengue type 2 (DEN-2)-infected suckling mouse brain (SMB) supernatant fluids. The high-molecular-weight fraction, which was eluted in the void volume, showed no increase in type specificity when tested against immune ascitic fluid to the four prototype dengue viruses. A void-volume fraction obtained after the infected SMB supernatant fluids were treated with urea displayed significant increases in complement fixation (CF) type specificity. Immune ascitic fluid prepared against the more typespecific DEN-2 antigen demonstrated neutralizing ability and greater CF type specificity. When DEN-2 sucrose-acetone-extracted hemagglutinating (HA) antigens were treated with 6 m urea at 37 C for various time intervals, all HA antigen was destroyed in 15 min. Urea treatment of infected SMB supernatant fluids indicated that the CF antigens were more stable to the effect of urea than were the HA antigens. After urea treatment of the SMB supernatant fluids, the CF type specificity increased as the hemagglutination inhibition titer decreased.

Animals↗