Table 1.

Proportion of sera from confirmed and unconfirmed cases of leptospirosis and groups of control individuals which recognize leptospiral proteins by immunoblottinga

Protein% Sera with IgG reactivity in:
Leptospirosis casesbControl groupsc
Confirmed (n = 73)Probable (n = 11)Unconfirmed (n = 16) Healthy community individuals Blood bank donors VDRL positive individuals Cases of hepatitis Cases of dengue
Acute phaseConvalescent phase % Sero- conversiondAcute phaseConvalescent phase % Sero- conversion Acute phaseConvalescent phase % Sero- conversion (n = 60 ) (n = 30) (n = 15) (n = 15)(n = 15 )
p82 1734f25 18 27 913 19 6 5 3 7 7
p7618f49f3618 27 9 13 13 2 7 7
p7010 10 6 6 19 13 7 320
p62 45f59f16 18 18 19 1910 23 7
p58 5 8 4 93 7 7
p4816f25f129 18 9 6 6 3 10
p4522 59f41 9 18 18 1931 13 10 3 7
p44 5 10 75 3 7
p41/42ce21f36f18 9 9 9 19 3113 7 10 20 7
p3721f29f139 9 6 13 13 5 7 13
p3237f84f5036 73 45 6 25 25 5 13
p31 3 17 16 9 9
p25 4 4 12
  • a The chi-square test was used to compare the frequencies of band recognition of sera from leptospirosis cases with those of sera from healthy community individuals (n = 60) . Values of zero are not shown to improve clarity.

  • b Paired acute- and convalescent-phase samples were tested for all leptospirosis cases. A confirmed leptospirosis case was defined as having a fourfold rise in the microagglutination test titer between paired serum samples or a titer of greater than 1:800 in one or more samples. Probable leptospirosis was defined as having a titer of ≥1:200 in a single sample.

  • c Control groups were chosen among residents of the city of Salvador, Brazil. Healthy community individuals were selected randomly from participants of a city-wide population-based seroprevalence survey. VDRL, Venereal Disease Research Laboratory test.

  • d Seroconversion was defined for patients whose samples were shown by immunoblotting to be nonreactive during the acute phase of illness and reactive during the convalescent phase. Proportions are calculated from the total numbers of sample pairs evaluated in the immunoblot analysis.

  • e The p41/42 complex (p41/42) includes at least two antigen moieties that could not be consistently distinguished in these SDS-PAGE and immunoblot analyses. Proportions were calculated based on a reaction to any of the moieties in this complex.

  • f The difference (by chi-square test) between frequencies of band recognition of sera from leptospirosis cases and those of sera from healthy community individuals (n = 60) is statistically significant (P < 0.05) .