Carrier Rate and Duration of Carrier State of Vibrio parahaemolyticus in Healthy Adults
1969 Volume 43 Issue 3 Pages 51-58
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1969 Volume 43 Issue 3 Pages 51-58
Periodic observations were made on 450 healthy kitchen workers of two heavy industry companies (330), two food-stuff dealers companies (80), a medical institute (20) and a school (20) in Kobe city for the study of carrier rate and duration of carrier state of Vibrio parahaemolyticus (VP) during oneyear-period from Jan. to Dec., 1968. The results obtained were evaluated as to whether VP carriers play a significant role as the source of foodpoisoning epidemics.
Isolations of Vibrio alginolyticus (VA), which is said to be non-pathogenic, were paralleled in addition.
The number of persons, who were found to be VP carrier state in the period, is 17 in all, approximately 0.3% of all examined. A period, in which VP was detectable, was only from June to October, that is compatible with the fact that VP is densely distributed in the coastal sea at that period. Monthly rate of VP isolations was 0.2% for June, 0.2 July, 0.6 August, 0.3 September, and 0.2 October.
Isolation rate of VA was almost the same as that of VP. Fifteen persons were found positive during May-October, 5 of which were concomitantly VP carriers.
Out of 17 cases from which VP strains were detected, hemolytic (Kanagawa phenomenonpositive) strains were found in only three. In one case of these three, mild diarrhea was observed shortly after the stool sampling. No clinical symptoms were seen in either VP or VA carriers except anabove-mentioned case.
In 27 cases, positive of VP and/or VA, its carrier state was investigated. In all the cases, the organisms disappeared within 3-7 days after the first isolation. It is a sharp contrast with VP food-poisoning cases observed in this country, in which the organisms were detectable mostly as long as 10 to 16 days after the onset of illness.
It is assumed from these findings that healthy adults cannot be long-term and dangerous carriers of VP as long as conditions such as amount of VP intake or resistance of the hosts are not favorable for them to become clinically manifested. Consequently, possibilities for such “healthy transient excreters” to become the source of epidemics would be quite low compared with those for manifested or convarescent patients, if not totally denied.
