Acute nephritis and streptococcal sore throat: a prospective study in general practice.

Abstract

The evidence linking acute nephritis and infection of the throat or skin with certain types of group A beta-haemolytic strepto cocci is of three kinds : (1) studies of streptococcal disease when acute nephritis was more prevalent than usual, (2) cultures from the throats of established cases of acute nephritis, and (3) serological studies of such cases for type-specific antibodies. Examples of the first are the reports of Manser and Wilson (1952), Reed (1953), Kleinman (1954), Seigel et al. (1955), Stetson et al. (1955), and George et al. (1958). Studies of established cases of acute nephritis have been reported by Rammelkamp and Weaver (1953), Wertheim et al. (1953), Wilmers et al. (1954), Hardin et al. (1956), and Bernstein and Stillerman (1960). Two investigations on the production of type-specific antibodies are noteworthy?those of Cullhed et al. (1959) and of Earle and Jennings (1959). The strain most often found in association with acute nephritis is type 12, but types 4, 25, and 49 are also thought to be nephritogenic. The evidence provided by these varied reports is incomplete and open to objections. The epidemics studied may not reflect the experience of normal communities. Strains isolated from established cases of acute nephritis may differ from the original Infecting organisms, as reinfection with a different type is known to occur (Ravenswaay, 1944, Rantz et al., 1945). In assessing the significance of such isolations it is essential to know the prevalence of different types in the community from which the cases are drawn. There are, however, few reports on the rela tive incidence of different types in acute pharyngitis in normal populations ; what evidence there is suggests that type 12 is widely prevalent (Siegel et al., 1961 ; Mitchell, 1962 ; Valkenburg et al., 1963). Moreover, the literature abounds in anomalies. Acute nephritis is said to be twice as common in males (Seegal et al., 1935 ; Earle and Seegal, 1957), though there is no evidence that infection with nephritogenic types shows a similar sex incidence. Only a minority of those infected by type 12 streptococci actually develop acute nephritis, and the incidence following type 12 infections varies (Rammelkamp, 1957). Other types have been isolated from cases of acute nephritis (Wertheim et al., 1953 ; Goldsmith et al., 1958 ; Mitchell, 1962). Urinary abnormalities without other signs of renal disease, while com moner and more notable after type 12 infections, may also occur after infection with other types, or after non-streptococcal infections (Stetson et al., 1955). Only one of the reports quoted was a prospective study, and this was carried out in a military camp where acute nephritis was already prevalent (Stetson et al., 1955). The only example of such a study in a normal community that we were able to find up to 1958 was reported by Rammelkamp et al. (1952) in a group of 60 families, and one other (Goslings et al., 1963) has since appeared. We report here a prospective study in a normal community : in a small town and the neighbouring countryside, virtually the whole population of which is under our care. In 1959 this population numbered approximately 14,000 persons ; the study began on 28 January of that year and continued for 12 months.