INTRADERMAL CHOLERA VACCINATION

The protection afforded by cholera vaccine administered by the intradermal route, and demonstrated by active and passive mouse protection tests, active guinea-pig protection tests, and agglutination titres, is excellent and equal to that given by subcutaneous inoculation.

It is suggested that cholera vaccine administered by the intradermal route would greatly reduce the incidence of reactions which occur when the vaccine is given subcutaneously.

EFFECT OF MUKERJEE'S GROUP IV PHAGE ON EL TOR VIBRIOS

El Tor vibrios are characterized by their insusceptibility to Mukerjee's group IV phage in routine test dilutions. This study shows that group IV phage in sufficient titre will produce, on lawns of El Tor vibrios, clearing resembling phage lysis. However, when the phage is mixed with El Tor cultures, a fall occurs in the viable count of both bacteria and phage. Darkfield microscopy shows that the bacteria lose their motility; measurement of the mixture's optical density indicates that bacterial lysis does occur.Evidence to date provides no indication that group IV phage undergoes multiplication in the El Tor vibrios tested, all of which were isolated during several recent outbreaks of cholera. Because of the marked difference in its behaviour towards them, phage IV is valuable in differentiating true cholera from El Tor vibrios.

OBSERVATIONS ON THE SPREAD OF CHOLERA IN HONG KONG, 1961-1963

Cholera, which had been spreading throughout the south-west Pacific in 1961, broke out in Hong Kong in August of that year. The outbreak lasted about six weeks, and recurred in 1962 and 1963; but whereas the 1961 outbreak resembled classical cholera, in the succeeding years the pattern changed. The disease, though still severe, was sporadic and this made it possible to study the epidemiology of the outbreak in some detail. Transmission bore little relation to water or food. A technique of nightsoil sampling was devised, and the results obtained in 1963 indicated the presence of a large number of symptomless excretors of cholera vibrios among the population. The authors suggest that this would make the hypothesis of person-to-person spread a more reasonable proposition than transmission simply from case to case.