ABSTRACT
Objective To investigate rickettsiae infection from host animals and vector arthropods in some areas of Yunnan Province. Methods Rat clip and cage traps were used to capture mice. Chiggers from body surface of mice and ticks from body surface of farm cattle were collected. DNAs were extracted from mice spleens, chiggers and ticks. Rickettsiae groEL segment were amplified by nested-polymerase chain reaction (nPCR), sequenced to analyze the homology with other known sequences. Results A total of 410 samples were collected for rickettsiae groEL segment detection with nPCR and 19 samples (4.63%) showed positive for rickettsiae groEL segment . Among them, 2.68%(11/410)were positive for Orientia tsutsugamsushi (Ot) groEL segment, and 1.22%(5/410)were positive for spotted fever group rickettsia (SFGR) groEL segment, and 0.49%(2/410)were positive for rickettsia mooseri (Rm) groEL segment, and 0.24%(1/410)were positive for rickettsia endosymbiont(Re) groEL segment. When analyzed the homology with other known sequences, 11Ot strains with 93.6%-100% similarities among them in this study shared the highest similarity with other Ot strains from GenBank respectively, reached up to 96.1%-100%; The groEL segments of 5 SFGR strains with 92.1%-99.5% similarities among them in this study shared highest similarity with other SFGR strains from other GenBank respectively, reached up to 98.9%-100%; In this study groEL segments of 2 Rm strains all showed 100% similarity with Wilmington strain (GenBank No:AE017197); One groEL segment of Re showed 98.9% similarity with Re strain (GenBank No:EU435143). Conclusion There were kinds of rickettsiaes infection in host animals and vector arthropods in Yunnan Province, so the monitoring and prevention of the Rickettsiosis should be strengthened.
ABSTRACT
We investigated epidemiological characteristic of scrub typhus in Yongshan County,Yunnan Province,China. The serum samples were collected from the patients with fever for detecting the antibody against Orientia tsutsugamsushi (Ot) by colloidal gold immunoassay assay.Rat traps were used to capture rodents.The spleen tissues of the captured rodents were detected by nested-polymerase chain reaction for rickettsia groEL segment.The groEL segments were sequenced and analyzed the homology with the other known sequences.Thirty-four scrub typhus cases were found in Yongshan County,Yunnan Prov-ince from May 2015 to October 2015.Among them,21 cases were confirmed by laboratory tests and 13 cases were clinical di-agnosis diseases.Of these patients,32.35% of the cases occurred in June.The 32.35% were in the group of the 40-49 year-old,and 79.41% were farmers,94.12% exhibited eschar or skin ulcer(31.25% were observed in groin of these cases),and rash developed in 50%.In 39 spleen tissue samples of Rattus flavipectus,9 samples showed positive for groEL gene Ot,but gro-EL gene of Typhus group rickettsia and spotted fever group rickettsia were negative.Sequence analysis showed that YSP30 was closely related to some Saitama related strains of Ot,such as HSB1,FAR1 and UAP4,while the other 8 strains were closely related to some Karp related strains of Ot,such as UT213,UT221 and SH205.It was confirmed that the Yongshan County was the natural foci of scrub typhus by the serological and molecular biological detections.There are Karp and Saitama genotype related Ots in the natural foci.
ABSTRACT
Objective To understand the epidemiologic characteristics of endemic typhus in Baoshan city. Methods Epidemiological data were collected and characteristics were analyzed. IgG antibody(Ab) of Rickettsia mooseri and Orientia tsutsuganushi in serum of patients were tested using both Weil-Felix and IFA method. The Rickettsia mooseri gltA gene, Rickettsia prowazekii gltA gene,Orientia tsutsugamushi 56 kDa protein gene, SFGR ompA gene, Ehrlichia sp. 16S rRNA gene and Anaplasma sp. 16S rRNA gene in spleen of mice were examined by PCR. Results Fifty- eight endemic typhus cases were found in Longyang district of Baoshan city, during July to August, 2009.Among them, 48 cases were confirmed by clinical diagnosis and 10 cases by laboratory tests. The Ab of Orientia tsutsugamushi Karp serotype was detected in 3 cases from laboratory diagnosis. The spleen samples from 85 Rattns flavipectus were tested using PCR. Of them, 3 samples for Rickettsia mooseri gltA gene showed positive (positive rate was 3.5% ), and the homology of 3 Rickettsia mooseri and Rickettsia mooseri Wilmington strain (GenBank U59714.1) was 100% through comparing gene sequence. The results of PCR for detecting Rickettsia prowazekii, Orientia tsutsugamushi, SFGR,Anaplasma sp. and Ehrlichia. sp were all negative. Conclusion The outbreak of endemic typhus was confirmed in Longyang district of Baoshan city through epidemiological data, clinical diagnosis and laboratory tests. Rickettsia mooseri DNA was detected in the dominant Raw flavipectus, suggesting that endemic typhus did exist in the local areas.
ABSTRACT
Objective To determine the hosts of hantavirus (HV) and its molecular epidemiological characteristics, to provide evidence for prevention and control on hemorrhagic fever with renal syndrome (HFRS). Methods Rodents were captured by a special trap within the residential area. The antigens of HV in lung tissues were detected by direct immuno-fluorescence assay (DFA). Nucleotide sequences of HV were amplified by RT-PCR with HV genotype-specific primer. The amplified genes were then sequenced. Phylogenetic tree were built on nucleotide sequence with Clusta1X 1.83 software. Results 1421 rodents were captured and classified into 8 species of 4 Genera in the epidemic area within 10 counties of Chuxiong prefecture, Yunnan province, between 2005 and 2006. Out of the 1421 rodents, 1056 (74.31%) of them were Rattus norvegicas and 280 (19.70%) belonged to Rattus flavipectus. The antigens of HV were detected by DFA in lung tissues and the total positive rate of HV was 5.15% (53/ 1029). After applying the sequencing nucleotide method to the 53 positive specimens, data showed that 21 specimens were positive and all of them belonged to Seoul type ( 15 samples were from Rattus norvegicus, 4 samples Rattasflavipectas, 2 samples Rattus nitidas). The partial S segments from 12 specimens were sequenced which appeared homologic with R22, L99 and HLD65 from GenBank in relatively high level (87.1%-99.7%). When compared to 76-118 strain of Hantaan type, their homologic degree was only 64.4%-69.1%. Results from Phylogenetic analysis showed that 12 specimens belonged to Seoul type. As for their homology, they were significantly similar to Seoul type and could be tentatively divided into two subtypes S1 and S3. Conclusion It was confirmed that the Seoul type virus, as HFRS' s pathogenetic agent mainly carried by rats, prevailed widely in Chuxiong prefecture. Owing to the local ecological environment, we also noticed the characteristics of different HV subtypes among Seoul type.