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

STREPTOCOCCOSIS 259Group B streptococci are important causal agents of neonatal disease. Group Astreptococci and Staphylococcus aureus were replaced by Escherichia coli andserogroup B streptococci as the principal agents of neonatal infection. In infectionscaused by group B streptococci (S. agalactiae), two clinical syndromes are distinguished,depending on the age of the infant at the onset of disease. The acute orearly-onset syndrome appears between the first and fifth day of life and is characterizedby sepsis and respiratory difficulty. The delayed-onset syndrome generallyappears after the tenth day and is characterized by meningitis, with or without sepsis.Affected children show lethargy, convulsions, and anorexia. Mortality is high inboth forms, but higher in the early-onset syndrome.In older children and adults, group B streptococci cause a variety of clinical syndromes:urinary tract infections, bacteremia, gangrene, postpartum infection, pneumonia,endocarditis, empyema, meningitis, and other pathological conditions(Patterson and el Batool Hafeez, 1976).Disease caused by group C streptococci (S. equi) is sporadic and rare in man.However, in 1983, an epidemic outbreak occurred in New Mexico (USA), with 16cases caused by the consumption of white cheese made at home with unpasteurizedmilk. The agent was identified as S. zooepidemicus, one of the four species thatmake up group C. The disease in these patients consisted of fever, chills, and vagueconstitutional symptoms, but five of them had a localized infection, which manifestedin such varied symptoms as pneumonia, endocarditis, meningitis, pericarditis,and abdominal pains (CDC, 1983).In England and Wales between 1983 and 1984, there were eight deaths during 32outbreaks associated with milk and milk products contaminated by S. zooepidemicus(Barrett, 1986). There were 11 cases in Hong Kong between 1982 and 1990 inpatients suffering from septicemia associated with a cardiovascular illness.Mortality was 22%. Five of the 11 patients had a predisposing disease. The sourceof infection was undercooked or raw pork (Yuen et al., 1990).In sporadic cases caused by streptococcus group C, the most common clinicalmanifestation is exudative pharyngitis or tonsillitis. With some exceptions, group Cstreptococci isolated from these cases belong to S. equisimilis, which produces septicemiain suckling pigs. An outbreak of pharyngitis caused by group C streptococci,due to the consumption of raw milk, was followed by a high incidence of glomerulonephritis(Duca et al., 1969).Both enterococcal and nonenterococcal group D streptococci cause serious diseasesin man. S. bovis causes bacteremia and endocarditis, and enterococci causeurinary tract infections, abdominal abscesses, and a significant percentage of casesof bacterial endocarditis. S. suis, already described, belongs to group D.Streptococci belonging to other serogroups, as well as those not serologicallygrouped, cause a wide variety of clinical manifestations, including dental caries andabscesses, meningitis, puerperal sepsis, wound infections, endocarditis, and otherpathological conditions (Kunz and Moellering, 1981).Nonhemolytic streptococci and “viridans” type (a-hemolytic) streptococci cancause subacute endocarditis.The preferred antimicrobial for treatment is penicillin (Benenson, 1990).The Disease in Animals: S. suis belongs to group D and can be β- or α-hemolytic(Timoney et al., 1988). This agent frequently causes septicemia, meningitis, pneu-