Molecular epidemiological study on the host and role of the Hantavirus and Orientia tsutsugamushi in the same epidemic area / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate whether Hantavirus (HV) and Orientia tsutsugamushi ( OT) can naturally infect and coexist in their host and role.</p><p><b>METHODS</b>By field epidemiological study, Leptotrombidium scutellare (3829) was collected and separated from mice(166) in epidemic areas. The cells of mites separated from their host and role were cultured. PCR was used to detect HV-RNA and OT-DNA in the cell culture.</p><p><b>RESULTS</b>In 105 Apodemus agrarius, 3 HV-RNA positive, 2 OT-DNA positive and 2 coinfection with HV and OT were detected;in 41 Brown rattus, 2 HV-RNA positive, 1 OT-DNA positive and 1 co-infection with HV and OT were detected. From 15 mites co-infected with HV and OT, 2 strains of HV pathogen, 2 strains of OT pathogen were separated and 1 HV and OT pathogen in the same mite were separate.</p><p><b>CONCLUSION</b>The study demonstrates that co-infection of HV and OT did simultaneously exist in wild Leptotrombidium scutellare. This theory has some significance to the epidemic and precaution of HV and OT.</p>

Amplification and restriction fragment length polymorphism analysis on the complete sequence of Sta56 gene of Orientia tsutsugamushi isolated from Shandong area / 中华流行病学杂志

<p><b>OBJECTIVE</b>To analyze the genetic differences of Orientia tsutsugamushi (Ot) Sta56 gene between Shandong isolates and other strains deposited in GenBank.</p><p><b>METHODS</b>PCR and restriction fragment length polymorphism (RFLP) were used to amplify the complete sequence of Ot-Sta56 gene. RFLP profiles of Ot were predicted by a computer program according to their complete sequences of Ot-Sta56 gene. PCR amplicon from XDM2 strain was sequenced and analyzed by Clustal X (1.8) and PHYLIP software.</p><p><b>RESULTS</b>The complete sequences (about 1.6 kbp) of Ot-Sta56 gene were amplified from B16 strain (isolated from patients), FXS2 strain (isolated from A. agrarius) and XDM2 strain. Four species of restriction endonucleases (Hha I, Hinf I, Hae III, Pst I) were used to digest the PCR amplicons from the 3 isolates. When comparing with the RFLP profiles of prototype Ot, the RFLP profiles of PCR amplicons from the 3 isolates were similar to those of Japan Kawasaki strain, but were quite different from the international reference strains Gilliam, Karp, Kato. Results from DNA sequence analysis showed that the complete sequence of Ot-Sta56 gene homology to Japan Kawasaki strain of XDM2 strain was 97%, and deduced amino acid sequence was 92%.</p><p><b>CONCLUSION</b>Data from the complete sequence of Sta56 gene indicated that the genotypes of Ot isolates in Shandong province were similar, but with distinction from the Kawasaki strain.</p>

Amplification and typing of Sta56 gene of Orientia tsutsugamushi from Shandong province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To clarify the gene type of Orientia tsutsugamushi (Ot) from Shandong province.</p><p><b>METHODS</b>Nested-polymerase chain reaction (nPCR) was used to identify the gene type of 23 isolated Ot strains, 2 pools of homogenized leptotrombidium (L.) scutellare, 10 blood specimens of scrub typhus patients, and at the same time to compare with the international reference strains Gilliam, Karp, Kato. Sequencing analysis of the Sta56 gene was also used to further identify the precise gene types.</p><p><b>RESULTS</b>Of the 35 samples, 33 had the same products in the amplification of template Ot-DNA. They all belonged to Kawasaki strains endemic in Japan while 2 (FXS4 and LHGM2 strain) belonged to Karp strains. The Sta56 gene sequence homologies to Japan Kawasaki strain of the 2 representative strains (B-16 and FXS2 strain) of the 33 samples were 94.22%, 95.21% respectively, but they were less than 75.87% to other prototype strains; The homologies to Karp strain of FXS4 and LHGM2 strain were 83.03%, 96.45% respectively. B-16 and FXS2 strain were designated as of types strain Japan Kawasaki, FXS4 and LHGM2 as Karp strain.</p><p><b>CONCLUSION</b>The results indicated that the dominant Ot strains in Shandong Province were similar to Kawasaki strains, but Karp strains also existed.</p>