Showing papers on "El Tor published in 1971"

A shellfish-borne cholera outbreak in Malaysia

Abstract: 11,650 specimens were studied bacteriologically. 139 El Tor Inaba strains were isolated from the stool of suspected patients and contacts, from water of various wells and tributaries of Kelantan river, and from shellfish. 15 El Tor Inaba, 25 non-agglutinable and 10 partially-agglutinable and auto-agglutinable (rough) strains were demonstrated in edible types of shellfish. 55 non-agglutinable vibrios were isolated from stools of suspected patients, from shellfish and water, and were regarded as pathogenic. Shellfish and water were considered as predominant vehicles for the transmission of cholera in this outbreak. The short-term carrier state is emphasized and the causal relationship of cholera with carrier was found to be insignificant in this outbreak. Bacteriological significance of partially-agglutinable and auto-agglutinable (rough) El Tor vibrios is discussed.

Cholera incidence in a population offered cholera vaccination: comparison of cooperative and uncooperative groups

Abstract: From May 1964 to December 1965, a controlled field trial of the effectiveness of cholera and cholera El Tor vaccines was conducted in Negros Occidental, Philippines. Some people did not volunteer for vaccination, and of those who did some received cholera vaccine and others a control (typhoid) vaccine. After analysing he incidence of cholera among these three groups it was found that the morbidity and mortality rates were significantly higher in the unvaccinated group than in either the control vaccine group or the cholera vaccine group. This would indicate that the unvaccinated group is basically different from the vaccinated control group. The clinical course of the disease was the same whether the patient had been vaccinated or not. The reasons for non-vaccination were investigated and should be taken into account by public health agencies when immunization programmes are being planned.

Further Studies on Tamaoki's Antigen Factor S1 of Cholera Vibrio; Appearance in El Tor Vibrios and Comments on This Factor

Abstract: The antigen factor S1 could be demonstrated in laboratory strains of El Tor vibrios as well, though in a low frequency as compared with that of classical cholera vibrios. The rate of its occurrence in all the laboratory strains appeared to be related to the preservation period or age of them, but not to the mentioned categories of cholera vibrio or the serotypes. The strains possessing S1 were agglutinated with anti-R-serum in parallel and were sensitive to the killing effect of the complement. Although they were not rough variants by the conventional criteria, it may be said that they were in a precursor stage of the smooth-to-rough variation. This antigen as well as R antigen was detectable also in a part of newly isolated El Tor strains, but these strains were not sensitive to the complement as expected. To this case, the mentioned "age relation" in the laboratory strains is not applicable. The possibility of early development of the serological R variant in the epidemic strains was discussed on the data of the literature.