Search

Rhipicephalus microplus ticks are vectors for multiple pathogens infecting animals and humans. Although the medical importance of R. microplus has been well-recognized and studied in most areas of China, the occurrence of tick-borne Rickettsiales has seldom been investigated in Guizhou Province, Southwest China. In this study, we collected 276 R. microplus ticks from cattle (209 ticks) and goats (67 ticks) in three locations of Guizhou Province. The Rickettsia, Anaplasma, and Ehrlichia were detected by targeting the 16S rRNA gene and were further characterized by amplifying the key genes. One Rickettsia (Ca. Rickettsia jingxinensis), three Ehrlichia (E. canis, E. minasensis, Ehrlichia sp.), and four Anaplasma (A. capra, A. ovis, A. marginale, Ca. Anaplasma boleense) species were detected, and their gltA and groEL genes were recovered. Candidatus Rickettsia jingxinensis, a spotted fever group of Rickettsia, was detected in a high proportion of the tested ticks (88.89%, 100%, and 100% in ticks from the three locations, respectively), suggesting the possibility that animals may be exposed to this type of Rickettsia. All the 16S, gltA, groEL, and ompA sequences of these strains are 100% identical to strains reported in Ngawa, Sichuan Province. E. minasensis, A. marginale, and Candidatus Anaplasma boleense are known to infect livestock such as cattle. The potential effects on local husbandry should be considered. Notably, E. canis, A. ovis, and A. capra have been reported to infect humans. The relatively high positive rates in Qianxinan (20.99%, 9.88%, and 4.94%, respectively) may indicate the potential risk to local populations. Furthermore, the genetic analysis indicated that the E. minasensis strains in this study may represent a variant or recombinant. Our results indicated the extensive diversity of Rickettsiales in R. microplus ticks from Guizhou Province. The possible occurrence of rickettsiosis, ehrlichiosis, and anaplasmosis in humans and domestic animals in this area should be further considered and investigated. [ABSTRACT FROM AUTHOR]

Background: Shigellosis is a serious problem in Guizhou and Shigella sonnei is an increasingly prevalent etiologic agent of local shigellosis cases. No data, however, are available about the molecular characterization of the local isolates of S. sonnei. We have conducted this study to molecularly characterize the clinical isolates of S. sonnei in Guizhou Province. Results: 76 S. sonnei isolates, including four isolates from 1974–1982 and 72 isolates from 2008–2010, were used for analysis in this study. Pulsed-field gel electrophoresis (PFGE) based on XbaI digestion divided the 76 isolates into 38 PFGE patterns (PT) and 15 PTs were represented by more than one isolates with PT31 (N = 8) containing the most number of isolates, followed with PT2 (N = 6). Multiple-Locus Variable number tandem repeat (VNTR) Analysis (MLVA) based on seven VNTR loci discriminated them into 19 different MLVA types (MTs), and four MTs were represented by more than one isolate with MT4 (N = 39) containing the most number of isolates, followed with MT12 (N = 18). 15 Multilocus sequence typing (MLST) base on 15 loci differentiated the isolates into six sequence types (STs), among which four STs were novel. The most common STs are ST76 (N = 43) and ST116 (N = 25), accounting for 92.1%. Correlation between genetic relationships and geographical origins or isolation years was observed among the isolates studied. Majority of isolates were clustered in accordance with the origin of isolation years based on the genetic data, which were also from similar geographical origins. Conclusions: Our results revealed the molecular characteristics including the specific genotypes such as four novel STs, clonal relationship, and genetic changes of local isolates from different years, which enhances our understanding of molecular characteristics of S. sonnei and contributes to the prevention and control of shigellosis in Guizhou Province. [ABSTRACT FROM AUTHOR]

Background: Bacillus (B.) anthracis is the pathogen that causes fatal anthrax. Guizhou Province is an old foci of anthrax in the southwest of China. Human anthrax has also been frequently reported in Guizhou in recent year. However, there is limited information on the genetic background of local B. anthracis isolates in Guizhou Province. Strain-specific detection of this bacterium using molecular approaches has enhanced our knowledge of microbial genetics. In the present study, we employed Multiple Locus Variable Number Tandem Repeats (VNTR) Analysis (MLVA) assay to analyze the genetic characteristics of B. anthracis strains isolated in Guizhou Province and their relationships to worldwide distributed isolates. Results: A total of 32 isolates of B. anthracis from soil, human, cattle, dog and water of different anthrax epidemics in Guizhou Province from 2006 to 2011 were confirmed with phage lysis test, penicillin inhibition test and PCR. MLVA-8 discriminated them into 28 unique MLVA types (MT G1 - G28), which were novel MTs compared with the previous reports. Cluster tree based on 32 isolates from Guizhou Province and 76 worldwide distributed isolates (30 MTs) showed they were divided into three clusters, designated A, B and C. All the 32 isolates were distributed in cluster A, which were further grouped into A1, A2, A3 and A4 sub-clusters. 32 isolates from Guizhou Province were closely grouped in each of the sub-clusters, respectively. Minimum Spanning Tree (MST) based on the MLVA data showed that the 28 MLVA profiles of isolates from Guizhou Province and 30 MLVA profiles of worldwide distributed isolates formed three clonal complexes (CCs) and ten singletons. Conclusions: 28 novel MTs of B. anthracis from Guizhou were revealed and their relationships to worldwide isolates were showed. The results will provide important information for prevention of anthrax and also enhances our understanding of genetic characteristics of B. anthracis in China. [ABSTRACT FROM AUTHOR]

Background: Sustained human leptospirosis as well as death cases has been reported in Qiandongnan Prefecture, Southeast of Guizhou, China, recently, but these human patients were only clinically diagnosed, and leptospires have never been isolated from patients in these epidemic regions, In order to track the source of infection and understand the etiologic characteristic of leptospirosis, we performed rodent carrier surveillance for leptospirosis in the epidemic area in 2011. The population distribution of rodents in the epidemic regions was revealed. Results: Four strains of leptospire were isolated from Apodemus agrarius. Microscopic agglutination test (MAT) confirmed the four isolates belonged to leptospiral serogroup Icterohaemorrhagiae. Multilocus sequence typing (MLST) indicated that all the four strains were defined as sequence type 1(ST1), which is identical to the three strains isolated from Rattus tanezumi in Rongjiang County in 2007. Clustering analysis of the MLST data indicated that the local isolates exactly matched with reference strain of leptospiral serovar Lai strain 56601, which is consistent with anti-Leptospira antibody detection of patients using MAT. Conclusions: Apodemus agrarius may be the potentially important carrier of leptospirosis and the potential source of leptospiral infection in human, and serovar Lai maybe the epidemic serovar of Leptospira in the localities [ABSTRACT FROM AUTHOR]

Background: Strong laboratory capacity is essential for detecting and responding to emerging and re-emerging global health threats. We conducted a quantitative laboratory assessment during 2014-2015 in two resource-limited provinces in southern China, Guangxi and Guizhou in order to guide strategies for strengthening core capacities as required by the International Health Regulations (IHR 2005).Methods: We selected 28 public health and clinical laboratories from the provincial, prefecture and county levels through a quasi-random sampling approach. The 11-module World Health Organization (WHO) laboratory assessment tool was adapted to the local context in China. At each laboratory, modules were scored 0-100% through a combination of paper surveys, in-person interviews, and visual inspections. We defined module scores as strong (> = 85%), good (70-84%), weak (50-69%), and very weak (< 50%). We estimated overall capacity and compared module scores across the provincial, prefecture, and county levels.Results: Overall, laboratories in both provinces received strong or good scores for 10 of the 11 modules. These findings were primarily driven by strong and good scores from the two provincial level laboratories; prefecture and county laboratories were strong or good for only 8 and 6 modules, respectively. County laboratories received weak scores in 4 modules. The module, 'Public Health Functions' (e.g., surveillance and reporting practices) lagged far behind all other modules (mean score = 46%) across all three administrative levels. Findings across the two provinces were similar.Conclusions: Laboratories in Guangxi and Guizhou are generally performing well in laboratory capacity as required by IHR. However, we recommend targeted interventions particularly for county-level laboratories, where we identified a number of gaps. Given the importance of surveillance and reporting, addressing gaps in public health functions is likely to have the greatest positive impact for IHR requirements. The quantitative WHO laboratory assessment tool was useful in identifying both comparative strengths and weaknesses. However, prior to future assessments, the tool may need to be aligned with the new WHO IHR monitoring and evaluation framework. [ABSTRACT FROM AUTHOR]