Showing papers on "El Tor published in 1974"

Studies on Toxinogenesis in Vibrio cholerae. I. Isolation of Mutants with Altered Toxinogenicity

Abstract: Methods have been developed for the recognition of toxin production by individual colonies of Vibrio cholerae strain 569B Inaba and certain other (but not all) strains of V. cholerae. Following mutagenesis of strain 569B with nitrosoguanidine, mutants that produced less or no detectable enterotoxin were isolated. One mutant, which did not elaborate any toxin detectable in Oakley-Fulthorpe tests or in the rabbit skin test, was completely avirulent for infant rabbits, although it was prototrophic and colonized their intestines. A strain of V. cholerae biotype El Tor produced a toxin that lacked an antigenic determinant found in toxin elaborated by strain 569B Inaba.

Protection of suckling mice from experimental cholera by maternal immunization: comparison of the efficacy of whole-cell, ribosomal-derived, and enterotoxin immunogens.

Abstract: The susceptibility of suckling mice to oral infection with several different Vibrio cholerae was determined. Mice up to 10 days of age were uniformly susceptible to oral infection with 10(8) colony-forming units of virulent organisms. Age-dependent resistance occurred thereafter to a maximum at about 15 days of age. The efficacy of selected vaccines was compared by oral challenge of 8-day-old, passively immunized CFW mice. An Ogawa-derived ribosomal antigen was found to be superior to a commercial whole-cell vaccine or to purified cholera enterotoxin. The ribosomal antigen was 50- to 100-fold more protective than the other vaccines on a weight basis against otherwise lethal challenge with Ogawa, Inaba, or El Tor Ogawa serotypes.

Live Oral Cholera Vaccine: Evaluation of the Clinical Effectiveness of Two Strains in Humans

Abstract: El Tor Ogawa C14-S5 and EW-6, two live vaccine candidate strains, were given to volunteers in varying doses with and without bicarbonate. Vibrios were found in the stool of one of 32 men given the vaccine strain, and only three men developed a significant titer rise (fourfold or greater) at 2 weeks of vibriocidal or antitoxic antibody. Five men who had previously received 109 organisms of the C14-S5 strain were challenged subsequently with virulent Ogawa 395 Vibrio cholerae. The rate of clinical infection in these men was no different than in unvaccinated controls. It was demonstrated that the live oral cholera vaccines did not remain viable in the intestine long enough to act antigenically.

Cholera. Implications for the United States.

Abstract: RECENT events have focused renewed attention on cholera as a source of health concern for the United States. During the last week in August 1973, cholera outbreaks occurred in several cities in Italy. More than 200 cases with 23 deaths had been reported by the end of September. This represents a further westward extension of the pandemic of El Tor cholera that, in recent years, has spread from Asia through the Middle East to most of Africa and, on occasion, to Europe. In 1971, Spain and Portugal experienced outbreaks of cholera resulting from cases imported from Africa. In the past few years, more than 100 imported cases have been reported from various other European countries without evidence of subsequent spread. On Aug 25, 1973, a case of cholera occurred in Calhoun County, Texas. 1 The diagnosis was suspected by an alert physician. As a result, the patient, a 51-year-old man,

Some factors affecting the haemolytic activity of Vibrio cholerae.

Abstract: SUMMARY Three-day nutrient-broth cultures of Vibrio cholerae gave distinct and reproducible results when tested for haemolysis of sheep RBC. As a medium for detecting haemolysis, heart-infusion broth was no better, and brain-heart-infusion broth was less satisfactory. Lack of reproducibility, and difficulty in interpreting results, were experienced when medium containing glycerol was used and when attempts were made to detect haemolysin in young (8-hour or 1-day) cultures. Horse and human RBC were found too fragile for this test. Strains of V. cholerae could be separated into three biotypes: classical, El Tor, and an intermediate biotype to which many strains of the present pandemic belong. The latter strains are similar to the El Tor biotype but haemolysin negative. Hence, the haemolysin test, if performed by a reliable method, is a valuable epidemiological tool.

Heterophile antigens of organisms causing particularly dangerous infections and their action on human intestinal tissues

Abstract: To detect heterophile antigens similar to those of human small intestinal tissue in organisms responsible for particularly dangerous infections, strains varying in their degree of virulence were used:Vibrio cholerae Vibrio El Tor, vibrios of Heiberg's VI group, water-inhabiting and nonagglutinating vibrios, and virulent and avirulent strain ofPasteurella pestis. Heterophile antigens were detected in strains ofV. cholrae, V. El Tor, nonagglutinating vibrios with the ability to cause cholera, and in the virulent strain,P. pestis 232. No reaction was obtained with all the other strains tested.

El Tor Cholera in Singapore

Abstract: In 1972 the civilian population of Singapore suffered a small outbreak of El Tor cholera. Preventive measures were undertaken by the ANZUK (Australian, New Zealand and UK) Force, and no cases occurred in servicemen or their dependants. The outbreak, however, had some interesting epidemological features not without relevance to military community and contrasted in some ways both with classical cholera and other outbreaks of El Tor cholera in South .East Ash ••