[Occurrence of Leptospira serovars in old foci of leptospirosis].

In two old natural foci of leptospiroses in an Eastern Slovakian area an epidemiological investigation was made to detect persisting carriership in basis reservoirs-small mammals and the contact with leptospirae in population groups with an occupational risk. Using the microagglutination reaction (MAR), the authors examined 1,106 small mammals and detected in 50 cases, i.e. 4.5%, the presence of specific antibodies against leptospirae, most frequently in species Apodemus agrarius and Ap. flavicollis. Only in one instance a positive reaction was found in the main reservoir--Microtus arvalis. As to serovars, Leptospira grippotyphosa and the group L. sejroe dominated. Of 1,740 examined human sera (832 men, 908 women) 56 samples (3.2%) reacted in MAR (4.1% men, 2.4% women). The spectrum of serovars in positive subjects was the same as in the above mentioned reservoirs with a predominance of L. grippotyphosa and group L. sejroe. As compared with previous examinations made 18 years ago in small mammals, a decline of positivity to almost half was recorded (from 7.8% to 4.5%), a reduction of the number of serovars from 7 to 4 was observed, however, the positivity of dominating serovars did not decline. In humans a higher percentage of positivity to specific antibodies was found, as compared with the past, i.e. 3.0% as compared with 2.0%. The authors found differences in the frequency of different serovars. In the past serovar L. bratislava dominated in the above area, followed by L. grippotyphosa. At present the first place was held by L. grippotyphosa and the group of L. sejroe.(ABSTRACT TRUNCATED AT 250 WORDS)