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

170 BACTERIOSESserovars 4d and 4b of L. monocytogenes were isolated from three fatal cases ofneonatal listeriosis and from five aborted fetuses. In Argentina, there are few data onthe occurrence of human listeriosis. In Córdoba (Argentina), there are cases ofneonatal listeriosis each year, and these constitute between 2% and 3% of bacteriologicallyconfirmed sepsis (Paolasso, 1981). In a small town in the province ofBuenos Aires, Manzullo (1981) isolated L. monocytogenes type 1a from a bovinefetus, the vaginal exudate of the woman who milked the cows, and from the household’sfemale dog. In another town, Manzullo (1990) isolated the agent from awoman’s vaginal exudate and from the woman’s female cat. In a Buenos Aires medicalcenter, nine cases of listeriosis were diagnosed in 15 years, two of them fatal.Only one patient was not immunocompromised (Roncoroni et al., 1987).Most cases occur sporadically, but epidemic outbreaks have occurred in severalcountries. In 1981, in a maternity hospital in Halifax (Canada), there were 34 perinatalcases and 7 cases in women without underlying illness or immunosuppression.Case fatality in the babies born live was 27%. There were five spontaneous abortionsand four babies stillborn at term. The epidemic outbreak was attributed to coleslaw:L. monocytogenes serovar 4b was isolated from the cabbage as well as from thepatients. On the farm where the cabbages were grown, two sheep had died from listeriosisthe previous year; in addition, the farmer used sheep dung as fertilizer. It isalso worth noting that the farmer kept the cabbage refrigerated at 4°C, whichallowed the etiologic agent to multiply at the expense of other contaminant microorganisms(Schlech et al., 1983).An earlier outbreak occurred in 1979 in eight hospitals in Boston (USA); itaffected 20 patients, 15 of whom acquired the infection in the hospital. Raw vegetableswere assumed to be the source of infection.In Massachusetts (USA), an epidemic outbreak caused by pasteurized milk wasrecorded in 1983. It affected 42 immunocompromised patients and seven immunocompetentpatients; there were also perinatal cases. Case fatality was 29%. Of 40isolates, 32 were type 4b. It is possible that the milk had been contaminated afterpasteurization (Schuchat et al., 1991).The largest epidemic in the US was recorded in 1985 in Los Angeles, California(Linnan et al., 1988). The epidemic affected pregnant women, their fetuses, andtheir newborns. Case fatality was 63% for the infected fetuses and newborns. Theoutbreak was due to a Mexican soft cheese; serovar 4b was isolated from the patientsand the cheese. The incubation period was 11 to 70 days, with an average of 31 days(Schuchat et al., 1991).There have been epidemic outbreaks in Switzerland, Denmark, and France. InSwitzerland, the 1987 outbreak that led to 64 perinatal cases and 58 nonperinatalcases was caused by a soft cheese. Case fatality was 28%. The strain of L. monocytogenesresponsible was the same enzymatic type as the strain that caused the outbreakin California in 1985 (Gelin and Broome, 1989). One of the largest epidemicsknown to date occurred in France in 1992. It affected 691 persons and 40% of thecases were caused by serotype 4b. The epidemic strain was isolated from 91 pregnantwomen and their children. Of the remaining persons affected by the epidemicstrain, 61% were immunodeficient. The phage type was the same as in California(1985), Switzerland (1983–1987), and Denmark (1985–1987). The epidemic strainwas isolated from 163 samples of meat products, 35 cheese samples, and 12 otherfood samples. The epidemic lasted from 18 March to 23 December 1992 and caused