ABSTRACT
Objective To establish recombinant outer membrane lipoprotein LipL32-based antibody detection assays in identifying leptospirosis. Methods Recombinant leptospiral outer membrane protein LipL32 was obtained by genetic engineering method. This purified protein was used in the indirect and sandwich ELISA assays to test the antibodies in sera of human beings and rats, and the results were compared with those obtained by microscopy agglutination test (MAT) and imported ELISA kit. Results When the acute and convalescent phase specimens from 9 leptospiral patients were tested, the detected rates of three ELISAs were similar to the MAT. Among the 45 probable cases which MAT showed positive, 32 (71.11%) samples were positive by r32-I-ELISA, 36(80.00%) by r32-S-ELISA,while 28.89% (13/45) samples were positive and 55.56% (25/45)were suspicious by D.A.I-ELISA. The specificity of r32-I-ELISA and r32-S-ELISA were 97.10 % (67/69) for 69 specimens. 43 healthy specimens were negative by both r32-I-ELISA and r32-S-ELISA, 14 healthy specimens were negative by D.A.I-ELISA. Among 16 non-leptospirosis patients, two specimens were positive by r32-I-ELISA and r32-S-ELISA, D.A.I-ELISA and identified one positive specimen, while 12 specimens were suspicious by D.A.I-ELISA. For 10 syphilis specimens, data obtained through three ELISAs were in consistent with that by MAT. A sandwiched ELISA, using rLipL32 protein as the antigen was developed to detect rat sera. Considering MAT as standard test, the sensitivity and specificity were 86.75 % (131/151), 99.19 % (122/123) respectively with coincidence rate as 92.34% (253/274). Conclusion The recombinant protein LipL32 had high immunoresctivity and could be used as an antigen for the detection of panthogenic leptospirosis. In summary, the novel sandwiched ELISA with rLipL32 showed similar sensitivity and specificity to that of MAT in the antibody detection of rat leptospirosis. It was suitable for large scales field sero-epidemiological studies.
ABSTRACT
<p><b>OBJECTIVE</b>To understand the sero-prevalence of hepatitis E virus (HEV) infection among different populations and animals in Fujian province.</p><p><b>METHODS</b>One thousand one hundred and fifty-one serum samples were collected from 5 species of animals including swine, dog, cow, sheep and rat. A total of 2209 and 1722 serum samples from the general population and from the exposed population were collected. Anti-HEV IgG was detected by ELISA. The general population was composed of healthy blood donors and the individuals who had attended physical examination including farmers, handlers, veterinarians, cooks who worked with pigs or chickens while the poultry wholesale suppliers made up the exposure population.</p><p><b>RESULTS</b>The infection rates of HEV in animals were different between species (chi2 = 406.25, P < 0.01) with the highest seen in the pig group. With pigs being kept at home, the rates were between 70.00% and 94.12% but the rate was 39.77% for those families that keeping the pigs at farms. The infection rate of HEV was 23.3% in the general population and 33.3% in the exposed populations, respectively. A significantly higher infection rate for anti-HEV was found in the exposed population when comparing with general population. The positive rate of anti-HEV IgG was significantly higher in the exposed population that closely having had contact with chickens than those who had contact with pigs. The increasing trend of HEV infection rate with age had been found but there was no significant difference between males and females in the general population. In the exposed population, the infection rate in males was significantly higher than that in females.</p><p><b>CONCLUSION</b>The infection ratse of HEV in pigs and in the exposure population were much higher, especially for those persons in close contact with chickens or pigs, suggesting that the sub-clinical infection for HEV might exist. These data further supported the hypothesis that HEV might have been an zoonotic disease.</p>