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

258 BACTERIOSESgroup D. There are other Streptococcus species that are common to both manand animals, but which may or may not have specific reservoirs for differentanimal species.Geographic Distribution: Streptococci are distributed worldwide. S. suis isprobably prevalent in all areas where swine are bred.Occurrence in Man: Disease caused by S. suis in man is rare. Between 1968 and1984, it was isolated from 30 cases of meningitis in the Netherlands; another 30cases caused by this agent occurred outside that country from 1968 to 1985 (Arendsand Zanen, 1988).Infections caused by group A (S. pyogenes) are common in man, with an apparentlyhigher prevalence in temperate climates. For a long time, streptococci belongingto serogroup B (S. agalactiae) were considered mainly pathogenic for animals.They are now recognized as one of the major causes of septicemia, pneumonia, andmeningitis in human newborns. In addition, streptococci belonging to serogroup D(S. bovis) are a frequent cause of endocarditis and bacteremia in man. There are sporadiccases of disease caused by streptococci belonging to groups C, G, F, H, andothers. In man, there have been rare cases due to S. acidominimus, which is foundin milk and in the genital and intestinal tracts of cattle; to S. uberis, which causesmastitis in cows and is found in milk, the oropharynx, skin, and intestinal tract; toS. lactis and S. cremoris, which cause mastitis in cows and are found in cow milk;and to S. equi and its subspecies, S. zooepidemicus, which produce various diseasesin animals. Finally, there is S. canis, groups G, L, and M (Gallis, 1990).Occurrence in Animals: Some diseases are very common and economicallyimportant. These include mastitis in cows caused by S. agalactiae (group B) andstrangles caused by S. equi (group C) in horses and S. suis in swine.The Disease in Man: In the 60 cases recorded up to 1988, the clinically predominantform of infection caused by S. suis was meningitis. Most patients showedclassic symptoms of meningitis: severe headache, high fever, confusion, and stiffneck. More than 50% experienced a loss of auditory acuity. Other complicationswere arthritis and endophthalmitis. Mortality was 7%. Most patients were employedin occupations involving the handling of swine or their products (swine breeders,slaughterhouse workers, butchers, swine transporters). Of the 30 patients in theNetherlands, 28 cases were caused by S. suis type 2, 1 by type 4, and 1 by a strainthat could not be typed (Arends and Zanen, 1988). The same authors estimate thatin that country the risks for slaughterhouse workers and swine breeders would be 3per 100,000 inhabitants.S. pyogenes is the principal pathogen among hemolytic streptococci. This agentfrequently causes epidemics of septic sore throat and scarlet fever (streptococcaltonsillitis and pharyngitis), various suppurative processes, septicemias, puerperalsepsis, erysipelas, ulcerative endocarditis, and other localized infections.Streptococcal sore throat and scarlet fever are epidemiologically similar. The latteris differentiated clinically by the exanthema caused by strains producing an erythrogenictoxin. The disease is mild or inapparent in a high percentage of thoseinfected. Rheumatic fever is a sequela of streptococcal sore throat or scarlet feverand may be caused by any strain of group A. Glomerulonephritis is another complication,produced only by certain nephritogenic strains of the same group.