zoonoses and communicable diseases common to ... - PAHO/WHO

ENTEROCOLITIC YERSINIOSIS 123tive without presenting clinical symptoms. The isolates of Y. enterocolitica from theasymptomatic children were serotype O:3, but did not have the virulence propertiesattributed to virulent strains (Morris et al., 1991).Geographic Distribution: Worldwide. The agent has been isolated from animals,man, food, and water. The human disease has been confirmed on five continents andin more than 30 countries (Swaminathan et al., 1982). There are geographic differencesin the distribution of serotypes. Serotypes 3, 5, 9, and 27 are found in Europeand many countries on other continents with temperate or cold climates. Serotypes8, 13, 18, 20, and 21 appear primarily in the US. Serotype 8 has caused several epidemicoutbreaks (Carniel and Mollaret, 1990). Outside the Americas, serotype 8 hasbeen isolated from the fecal matter of a healthy dog and a piglet in Nigeria. None ofthese strains had virulence markers (Trimnell and Adesiyun, 1988).The serotype pattern is changing in the US. In New York City and New York State,serotype 3 appears most frequently; this is also true in California. From 1972 to1979, only two isolates of O:3 were confirmed in California, but the frequency ofthis serotype began to increase such that from 1986 to 1988 it was part of 41% ofall isolates of Y. enterocolitica (Bissett et al., 1990). This trend seems to be spreadingas serotype O:3 in children has emerged in Atlanta, Georgia and in other UScities (Lee et al., 1991).Occurrence in Man: There are marked differences in disease incidence betweendifferent regions and even between neighboring countries. The highest incidencerates are observed in Scandinavia, Belgium, several eastern European countries,Japan, South Africa, and Canada. The disease is less common in the United States,Great Britain, and France. In Belgium, the agent was isolated from 3,167 patientsbetween 1963 and 1978, with isolations increasing since then. Of the strains isolated,84% belonged to serotype 3, but isolations of serotype 9 have risen since then(de Groote et al., 1982). In Canada from 1966 to 1977, 1,000 isolations (serotype 3)were made from human patients, while in the US from 1973 to 1976, 68 casesoccurred, with serotype 8 predominating. Approximately 1% to 3% of acute enteritiscases in Sweden, the former West Germany, Belgium, and Canada are caused byY. enterocolitica (WHO Scientific Working Group, 1980). The lack of laboratoryfacilities hinders knowledge of disease incidence in developing countries. In tropicalareas, Y. enterocolitica seems to be a minor cause of diarrhea (Mata andSimhon, 1982).Most cases are sporadic or appear as small, familial outbreaks, but several epidemicshave also been described. Three of these outbreaks occurred in Japan in 1972and affected children and adolescents, with 189 cases in one epidemic, 198 inanother, and 544 in the third. The source of infection could not be determined. In1976, an outbreak in the state of New York affected 218 school children. The sourceof the infection was thought to be chocolate milk (possibly made with contaminatedchocolate syrup). An outbreak in 1982 in the US affected three states (Tennessee,Arkansas, and Mississippi), and caused 172 patients to be hospitalized. Serotypes 13and 18 of Y. enterocolitica, which are rare in the US, were isolated from thesepatients. Statistical association indicated milk from a single processing plant as thesource of infection (Tacket et al., 1984). An outbreak was reported in 1973 inFinland that affected 94 conscripts (Lindholm and Visakorpi, 1991). A study conductedin a hospital in the Basque country of Spain on 51 cases of yersiniosis