Molecular Epidemiological Survey Research Articles

Molecular epidemiological survey and phylogenetic analysis of bovine respiratory coronavirus in Japan from 2016 to 2018.

Bovine coronavirus (BCoV) is an etiological agent of bovine respiratory disease (BRD). BRD is a costly illness worldwide; thus, epidemiological surveys of BCoV are important. Here, we conducted a molecular epidemiological survey of BCoV in respiratory-diseased and healthy cattle in Japan from 2016 to 2018. We found that 21.2% (58/273) of the respiratory-diseased cattle were infected with BCoV. The respiratory-diseased cattle had virus amounts 4.7 times higher than those in the asymptomatic cattle. Phylogenetic analyses showed that the BCoV identified in Japan after 2005 formed an individual lineage that was distinct from the strains found in other countries. These results suggest that BCoV is epidemic and has evolved uniquely in Japan.

A novel genomic island harbouring lsa(E) and lnu(B) genes and a defective prophage in a Streptococcus pyogenes isolate resistant to lincosamide, streptogramin A and pleuromutilin antibiotics

A lincosamide-resistant and macrolide-susceptible phenotype has not been described to date in Streptococcus pyogenes [group A streptococcus (GAS)]. The aim of this study was to characterize a GAS isolate susceptible to macrolides but resistant to lincosamide, streptogramin A and pleuromutilin antibiotics. Antimicrobial susceptibility was tested using the microdilution broth method and the resistance phenotype was tested by D-test. The GAS2887HUB isolate was subjected to whole-genome sequencing. The isolate showed a positive Gots' test (clindamycin inactivation). Whole-genome sequencing revealed that the strain was ST10 and emm93, and had five resistance genes [lnu(B), ant(6)-Ia, aph(3')-III, tet(M) and dfrG]. The tet(M) gene was located in a Tn916-like transposon. The lsa(E)-lnu(B)-containing sequence (inserted downstream of the rumA gene) was formed by a 39.6-kb prophage, followed by a gene cluster encoding aminoglycoside-streptothricin resistance [ant(6)Ia-sat4-aph(3')III] and lsa(E)-lnu(B) genes. This structure was not transferred by conjugation. This study identified a new genetic element carrying a determinant of lincosamide resistance in a GAS. Further molecular epidemiological surveys are needed to determine the prevalence of this mechanism of resistance in GAS.

Prevalence and genetic characterization of Enterocytozoon bieneusi and Giardia duodenalis in Tibetan pigs in Tibet, China

Enterocytozoon bieneusi and Giardia duodenalis are important opportunistic enteric zoonotic pathogens that cause diarrhoea and intestinal diseases in animals and humans. China is the largest producer of pigs, but whether Tibetan pigs, a unique pig breed in Tibet, are infected with E. bieneusi and G. duodenalis is unknown. Therefore, we conducted a molecular epidemiological survey to determine the prevalence of E. bieneusi and G. duodenalis in Tibetan pigs in Tibet, China, and identified the genotypes of these causative agents. A total of 345 faecal specimens were collected from Tibetan pigs from three Tibet counties (Milin, Cuona and Gongbujiangda), examined by nested PCR and sequenced utilizing genetic markers in the ribosomal internal transcribed spacer (ITS) region of the rRNA and glutamate dehydrogenase (gdh) gene for E. bieneusi and G. duodenalis, respectively. Moreover, using multilocus sequence typing, the subtypes of E. bieneusi were identified based on four loci (MS1, MS3, MS4 and MS7). A total of 41 (11.88%) faecal samples from Tibetan pigs were E. bieneusi-positive, and 2 (0.58%) were G. duodenalis-positive. The multivariate logistic regression analysis showed that age was considered a risk factor for Tibetan pig infection of E. bieneusi. Two novel (GB11, GB31) and four known E. bieneusi genotypes (EbpC, EbpD, PigEBITS5 and CHS12) were identified and were all classified as zoonotic group 1 according to the phylogenetic analysis. Two MLGs (MLGI and MLGII) were further identified in the E. bieneusi EbpC genotype by multilocus sequence typing analysis. In addition, two G. duodenalis assemblages (D and E) were found in the present study. To our knowledge, the current study is the first to detect the prevalence and perform genetic characterization of G. duodenalis in Tibetan pigs in Tibet, China. The results could provide essential data for controlling E. bieneusi and G. duodenalis infections in Tibetan pigs that are in contact with other animals and humans, as Tibetan pigs could be a potential source for human infection by these pathogens.

Predominance of emm4 and antibiotic resistance of Streptococcus pyogenes in acute pharyngitis in a southern region of Korea.

Streptococcus pyogenes is the most common cause of bacterial pharyngitis. Genotyping of emm is useful for molecular epidemiological survey of S. pyogenes. Antibiotic resistance data are needed for empirical treatments. In total, 358 children in Changwon, Korea who had pharyngitis symptoms were subjected to throat cultures to isolate S. pyogenes in 2017. emm genotyping was performed by direct sequencing. An antibiotic susceptibility test was performed using the disk diffusion method for erythromycin (ERY), clindamycin (CLI), tetracycline (TET) and ofloxacin (OFX). Screening for macrolide resistance phenotype and its determinants was performed for the ERY-resistant strains. A total of 190 strains (53.1 %) of S. pyogenes were isolated from 358 children. The most frequent emm genotype was emm4 (53.2 %), followed by emm89 (12.6 %), emm28 (11.6 %) and emm1 (10 %). Antibiotic resistance rates to ERY, CLI, TET and OFX were 3.2 %, 2.6 %, 1.1 % and 2.6%, respectively. There were five isolates of the cMLSB phenotype having the ermB gene and one M phenotype harbouring the mefA gene. The distribution of emm genotypes was quite different from those previously reported in Korea. emm4 accounted for more than 50 % of the genotypes. Macrolide resistance rates remained very low, but five of six ERY-resistant strains displayed the cMLSB phenotype.

Genomic analysis of Staphylococcus aureus along a pork production chain and in the community, Shandong Province, China

Livestock-associated meticillin-resistant Staphylococcus aureus (LA-MRSA) is an increasingly important public health concern worldwide; however, data on LA-MRSA from Asian countries is scarce. As such, a comprehensive molecular epidemiological survey of S. aureus along a pork production chain and in the community was undertaken in Shandong Province, China. spa typing and whole-genome sequencing were used to survey the occurrence and potential transmission of S. aureus in various sectors, including 899 porcine samples (snout or skin swabs, carcass swabs and pork portions), 845 human nasal samples and 239 environmental samples from commercial farms, a slaughterhouse, a pork wholesale market and the surrounding community. MRSA was detected in higher frequencies in samples from two commercial pig farms (pigs, 49%; farm workers, 64%; environmental samples, 16%) than in samples from the slaughterhouse (fatteners, 8.2%; carcasses, 1.1%; operation workers, 0%; environmental samples, 3.8%), the pork wholesale market (pork, 14%; sellers, 0%) and individuals in the community (6.8%). There were significant differences in population structures, antimicrobial susceptibility profiles, and the presence of resistance and virulence genes between human- and pig-associated isolates. The phylogenetic analysis confirmed the dissemination of LA-MRSA between various segments along the pork production chain. However, MRSA of the same sequence type was not found to be disseminated between the commercial farms and the surrounding communities. Furthermore, one MRSA ST398 was observed, and a novel CC9 variant ST3597 was detected within the chain. The high MRSA carriage rates and the emergence of a new MRSA CC9 variant identified in this study highlight the need for MRSA surveillance.

Molecular characterization of the glycoprotein and fusion protein in human respiratory syncytial virus subgroup A: Emergence of ON-1 genotype in Iran

HRSV is a principle cause of infant hospitalization, childhood wheezing and a common pathogen in the elderly. Limited information exists regarding HRSV genotypes in Iran. In order to better understand HRSV strain diversity, we performed an in-depth evaluation of the genetic variability of the HRSV F protein detected in children under two years of age that, presented with acute respiratory symptoms during 2015–2016 in Tehran. A total of 180 nasopharyngeal swabs were evaluated. The HRSV positive samples were genotyped for G and F gene sequences using RT-PCR and sequencing methods. Phylogenetic analysis was performed using the neighbor-joining and maximum likelihood methods. Genetic and antigenic characteristics of the F gene, nucleotide and amino acids in significant positions and immune system binding regions, as well as the p-distance, positive/negative selection site, linear epitopes and glycosylation sites were investigated in all selected sequences. Among the 83 HRSV positive samples, the Fifty-five cases were successfully sequenced. All of them were classified as subgroup A and belonged to the ON-1 genotype, which possessed 72-nt duplication in the G gene. This study is the first report on the emergence of ON-1 in Iran. ON-1 Iranian sequences clustered in three lineages according to virus fusion (F) gene variations. F gene sequence analysis showed that all genetic changes in the isolates from Iran were base substitutions and no deletion/insertions were identified. The low dN/dS ratio and lack of positively selected sites showed that the fusion genes found in the strains from Iran are not under host selective pressure. Continuing and long-term molecular epidemiological surveys for early detection of circulating and newly emerging genotypes are necessary to gain a better understanding of their epidemic potential.

Human rotavirus in Iran; molecular epidemiology, genetic diversity and recent updates on vaccine advances.

Human rotavirus is the predominant pathogen causing gastroenteritis in infants and children younger than 5 years of age globally. Before introduction and implementation of rotavirus vaccine,more than frothy percent of all caused acute gastroenteritis hospitalization and nearly half a million deaths per year was occurred due to Rotavirus infection mostly in the low-income countries. Rotaviruses are divided in G and P genotypes, based on two genomic segments' nucleotide sequences VP7 and VP4, respectively. Currently, 27 G and 37 P types have been described; among them G1 to G4 and G9 and P[8], P[4], and P[6] genotypes are the most prevalent circulating rotavirus strains globally. Molecular epidemiological surveys revealed that G1P[8] is the predominant genotype in Iran, although other genotypes have also been reported. Rotavirus vaccine was recommended by the World Health Organization as a necessary part of national childhood immunization programs in 2009. Rotarix (monovalent) and RotaTeq (pantavalent) are two oral vaccines that have been available in more than one hundred countries around the world to control the viral infection and reduce the cases of diarrheal diseases. This article provides a review of frequency, molecular epidemiology and current situation of Rotavirus genetic diversity Iran. In addition, recent advances in rotavirus vaccine research are discussed.

Molecular epidemiology survey and characterization of human influenza A viruses circulating among Palestinians in East Jerusalem and the West Bank in 2015.

Frequent typing and molecular characterization of influenza A (IAV) strains are crucial for the identification of circulating subtypes and for the selection of the subtypes’ lineages to be included in the annually prepared vaccine cocktail. We investigated IAV sampled from an underrepresented population from Palestine. 200 nasopharyngeal aspirates (NPA) were collected between February and May of 2015 from Palestinians in East Jerusalem and the West Bank suffering from mild to severe symptoms of upper respiratory infections. NPA were screened for the presence of IAV using RT-PCR. Epidemiological data, hemagglutinin (HA) and neuraminidase (NA) gene sequences were analyzed in IAV positive samples. 50 samples tested positive for IAV; 48% of which were identified as A(H1N1)pdm09 and 52% as A(H3N2), respectively. Infection with A(H1N1)pdm09 occurred mainly in April, while A(H3N2) infections were mainly detected in March. Most IAV infections in 6-year-olds and below were attributed to subtype A(H3N2), while A(H1N1)pdm09 was responsible for most infections in adults above 18-year-olds. Analyses of HA and NA amino acid sequences revealed numerous substitutions. Thereafter, and based on the HA analysis, the Palestinian A(H1N1)pdm09 isolates fell into clade 6B, while the A(H3N2) isolates fell into clades 3C.2 and 3C.3, respectively. This study is significant in providing the first insight into the epidemiology and genetic properties of IAV circulating in Palestine. In contrast to international reports for the same season, A(H3N2) was not the dominant subtype as in northern hemisphere, nor was A(H1N1)pdm09 as in WHO reports for the Middle East, however genetic properties of Palestinian A(H3N2) and A(H1N1)pdm09 were in line with global isolates.

Tropheryma whipplei intestinal colonization in Italian and migrant population: a retrospective observational study.

To obtain the first molecular epidemiological survey of Tropheryma whipplei intestinal colonization in Italy.Materials& methods: Retrospective, observational study to assess the prevalence of T. whipplei, the causative agent of Whipple's disease, in stool samples (real-time PCR) of patients attending the Center for Tropical Diseases (Italy) and risk factors associated. Overall prevalence was 6.9% (85/1240). The younger age group showed a significantly higher rate than older age group (12.7 vs 5.9%, p=0.002). The prevalence was 4.9% for Italians and 9.3% for migrants (p=0.003). Among the latter, children less than 10 years had higher prevalence than older ones (17.3 vs 7.3%, p=0.003). The young age, male gender and Giardia duodenalis and Entamoeba histolytica coinfection were risk factors. Our study confirms an increased risk of acquiring T. whipplei infection during childhood, under poor sanitary conditions.

Molecular epidemiology and phylogenetic analysis of Theileria species in sheep

A molecular epidemiological survey was carried out on theileriosis in sheep in six districts of northern Karnataka (India) from August 2017 to October 2018. A total of 525 (209 clinical cases and 316 healthy/tick infested) sheep blood samples were collected and analyzed by polymerase chain reaction (PCR) targeting 18S rRNA gene. In Theileria genus-specific PCR, 350 (148 clinical cases and 202 healthy/tick infested) samples showed specific amplification of 1098 bp DNA fragment with an overall prevalence of 66.67%. The prevalence of theileriosis among ages, genders and breeds in sheep was non-significant (P>0.05). In Theileria species-specific PCR, 297 (84.85%) samples amplified 389 bp fragment specific for T. luwenshuni and 6 (1.71%) samples amplified 520 bp fragment specific for T. ovis. T. luwenshuni was most predominant species followed by T. ovis with a mixed infection of 13.42%. In phylogenetic analysis by maximum likelihood, T. luwenshuni of north Karnataka isolate shared >99.5% homology with Indian isolates of T. luwenshuni and >99.2% homology with T. luwenshuni isolates of Chinese origin. T. ovis of north Karnataka isolate shared >99.8% homology with T. ovis isolates of Indian and Chinese origin. The findings indicated that PCR and phylogenetic analysis can be better molecular tools for understanding the molecular epidemiology and characterization of Theileria spp. at species level.

Disparate impact on CD4 T cell count by two distinct HIV-1 phylogenetic clusters from the same clade

HIV-1 evolved into various genetic subtypes and circulating recombinant forms (CRFs) in the global epidemic. The same subtype or CRF is usually considered to have similar phenotype. Being one of the world's major CRFs, CRF01_AE infection was reported to associate with higher prevalence of CXCR4 (X4) viruses and faster CD4 decline. However, the underlying mechanisms remain unclear. We identified eight phylogenetic clusters of CRF01_AE in China and hypothesized that they may have different phenotypes. In the National HIV Molecular Epidemiology Survey, we discovered that people infected by CRF01_AE cluster 4 had significantly lower CD4 counts (391 vs. 470, P < 0.0001) and higher prevalence of X4-using viruses (17.1% vs. 4.4%, P < 0.0001) compared with those infected by cluster 5. In an MSM cohort, X4-using viruses were only isolated from seroconvertors in cluster 4, which was associated with low a CD4 count within the first year of infection (141 vs. 440, P = 0.003). Using a coreceptor binding model, we identified unique V3 signatures in cluster 4 that favor CXCR4 use. We demonstrate that the HIV-1 phenotype and pathogenicity can be determined at the phylogenetic cluster level in the same subtype. Since its initial spread to humans from chimpanzees, estimated to be the first half of the 20th century, HIV-1 continues to undergo rapid evolution in larger and more diverse populations. The divergent phenotype evolution of two major CRF01_AE clusters highlights the importance of monitoring the genetic evolution and phenotypic shift of HIV-1 to provide early warning of the appearance of more pathogenic strains.

Multiple introductions and subsequent transmission of multidrug-resistant Candida auris in the USA: a molecular epidemiological survey

Transmission of multidrug-resistant Candida auris infection has been reported in the USA. To better understand its emergence and transmission dynamics and to guide clinical and public health responses, we did a molecular epidemiological investigation of C auris cases in the USA. In this molecular epidemiological survey, we used whole-genome sequencing to assess the genetic similarity between isolates collected from patients in ten US states (California, Connecticut, Florida, Illinois, Indiana, Maryland, Massachusetts, New Jersey, New York, and Oklahoma) and those identified in several other countries (Colombia, India, Japan, Pakistan, South Africa, South Korea, and Venezuela). We worked with state health departments, who provided us with isolates for sequencing. These isolates of C auris were collected during the normal course of clinical care (clinical cases) or as part of contact investigations or point prevalence surveys (screening cases). We integrated data from standardised case report forms and contact investigations, including travel history and epidemiological links (ie, patients that had shared a room or ward with a patient with C auris). Genetic diversity of C auris within a patient, a facility, and a state were evaluated by pairwise differences in single-nucleotide polymorphisms (SNPs). From May 11, 2013, to Aug 31, 2017, isolates that corresponded to 133 cases (73 clinical cases and 60 screening cases) were collected. Of 73 clinical cases, 66 (90%) cases involved isolates related to south Asian isolates, five (7%) cases were related to South American isolates, one (1%) case to African isolates, and one (1%) case to east Asian isolates. Most (60 [82%]) clinical cases were identified in New York and New Jersey; these isolates, although related to south Asian isolates, were genetically distinct. Genomic data corroborated five (7%) clinical cases in which patients probably acquired C auris through health-care exposures abroad. Among clinical and screening cases, the genetic diversity of C auris isolates within a person was similar to that within a facility during an outbreak (median SNP difference three SNPs, range 0-12). Isolates of C auris in the USA were genetically related to those from four global regions, suggesting that C auris was introduced into the USA several times. The five travel-related cases are examples of how introductions can occur. Genetic diversity among isolates from the same patients, health-care facilities, and states indicates that there is local and ongoing transmission. US Centers for Disease Control and Prevention.

Frequent Genetic Mismatch between Vaccine Strains and Circulating Seasonal Influenza Viruses, Hong Kong, China, 1996-2012.

The World Health Organization selects influenza vaccine compositions biannually to cater to peaks in temperate regions. In tropical and subtropical regions, where influenza seasonality varies and epidemics can occur year-round, the choice of vaccine remains uncertain. Our 17-year molecular epidemiologic survey showed that most influenza A(H3N2) (9/11) and B (6/7) vaccine strains had circulated in East Asia >1 year before inclusion into vaccines. Northern Hemisphere vaccine strains and circulating strains in East Asia were closely matched in 7 (20.6%) of 34 seasons for H3N2 and 5 (14.7%) of 34 seasons for B. Southern Hemisphere vaccines also had a low probability of matching (H3N2, 14.7%; B, 11.1%). Strain drift among seasons was common (H3N2, 41.2%; B, 35.3%), and biannual vaccination strategy (Northern Hemisphere vaccines in November followed by Southern Hemisphere vaccines in May) did not improve matching. East Asia is an important contributor to influenza surveillance but often has mismatch between vaccine and contemporarily circulating strains.

Characterization of a New HIV-1 CRF01_AE/B Recombinant Virus Form Among Men Who Have Sex with Men in Shanghai, China.

To date, there are 16 types of CRF01_AE/B circulating recombinant forms identified, and most of them are distributed in Asian countries such as China, Malaysia, and Singapore. Previous HIV molecular epidemiological surveys showed that CRF01_AE (27.6%) and B (9.6%) subtypes are predominant strains in mainland of China. At the same time, the HIV-1 virus spreads faster in the men who have sex with men (MSM) population than in other risk groups. In Shanghai district, ∼66.0% of newly reported cases were infected through homosexual transmission. In this study, we report a novel recombinant strain of CRF01_AE/B. The near full-length genome phylogenetic tree showed that the strain clustered with the CRF01_AE reference sequence and placed in the peripheral position within the branch of the CRF01_AE strain. Subregional evolutionary results indicated that the CRF01_AE subtype was derived from cluster 4 of CRF01_AE, which is mainly distributed in northern China. The subtype B was correlated with the U.S./Europe B, which are widely prevalent in the Chinese MSM population. In recent years, a large number of recombinant forms between CRF01_AE and B strains are continuously emerging in China. Therefore, understanding the current epidemic recombinant forms will have significant implications for prevention and treatment of HIV/AIDS.

First cross-sectional, molecular epidemiological survey of Cryptosporidium, Giardia and Enterocytozoon in alpaca (Vicugna pacos) in Australia

BackgroundEukaryotic pathogens, including Cryptosporidium, Giardia and Enterocytozoon, have been implicated in neonatal diarrhoea, leading to marked morbidity and mortality in the alpaca (Vicugna pacos) and llama (Lama glama) around the world. Australia has the largest population of alpacas outside of South America, but very little is known about these pathogens in alpaca populations in this country. Here, we undertook the first molecular epidemiological survey of Cryptosporidium, Giardia and Enterocytozoon in V. pacos in Australia.MethodsA cross-sectional survey of 81 herds, comprising alpacas of 6 weeks to 26 years of age, were sampled from the six Australian states (Queensland, New South Wales, Victoria, South Australia, Tasmania and Western Australia) across the four seasons. PCR-based sequencing was employed, utilising genetic markers in the small subunit of the nuclear ribosomal RNA (SSU) and 60-kilodalton glycoprotein (gp60) genes for Cryptosporidium, triose-phosphate isomerase (tpi) gene for Giardia duodenalis and the internal transcribed spacer region (ITS) for Enterocytozoon bieneusi.ResultsPCR-based analyses of 81 faecal DNA samples representing 1421 alpaca individuals detected Cryptosporidium, Giardia and/or Enterocytozoon on 15 farms in New South Wales, Victoria and South Australia, equating to 18.5% of all samples/herds tested. Cryptosporidium was detected on three (3.7%) farms, G. duodenalis on six (7.4%) and E. bieneusi on eight (9.9%) in two or all of these three states, but not in Queensland, Tasmania or Western Australia. Molecular analyses of selected faecal DNA samples from individual alpacas for Cryptosporidium, Giardia and/or Enterocytozoon consistently showed that alpacas of ≤ 6 months of age harboured these pathogens.ConclusionsThis first molecular investigation of Cryptosporidium, Giardia and Enterocytozoon in alpaca subpopulations in Australia has identified species and genotypes that are of likely importance as primary pathogens of alpacas, particularly young crias, and some genotypes with zoonotic potential. Although the prevalence established here in the alpaca subpopulations studied is low, the present findings suggest that crias are likely reservoirs of infections to susceptible alpacas and/or humans. Future studies should focus on investigating pre-weaned and post-weaned crias, and on exploring transmission patterns to establish what role particular genotypes play in neonatal or perinatal diarrhoea in alpacas and in zoonotic diseases in different states of Australia.

Molecular investigation of Cryptosporidium in farmed chickens in Hubei Province, China, identifies \u2018zoonotic\u2019 subtypes of C. meleagridis

BackgroundCryptosporidium is a key genus of parasitic protists that infect humans and other vertebrates (mammals and birds). Birds are typically infected with C. avium, C. baileyi, C. galli and/or C. meleagridis, the latter of which is recognised as being zoonotic. Stimulated by the previous finding of C. meleagridis subtypes IIIbA21G1R1, IIIbA22G1R1 and IIIbA26G1R1 in diarrhoeic children in Wuhan city and environs in Hubei Province, China, we performed a molecular epidemiological survey to explore whether these or similar subtypes might occur in farmed chickens in this province.MethodsPCR-coupled sequencing analyses of regions in the small subunit (SSU) of the nuclear ribosomal RNA and 60 kDa glycoprotein (gp60) genes were utilised to characterise Cryptosporidium in faecal samples from chickens (n = 471) from 14 farms from six distinct regions in Hubei Province.ResultsCryptosporidium baileyi (33/471; 7.0%) and C. meleagridis (15/471; 3.2%) were identified in chickens on eight farms in five of the six distinct geographical regions. No significant age-associated difference in the prevalence of C. baileyi was evident, whereas the prevalence of C. meleagridis was significantly higher in younger (≤ 4 months) than in older chickens (> 4 months). For C. meleagridis, two subtype families, IIIb and IIIe, were defined; some of the subtypes (i.e. IIIbA26G1R1b and IIIbA22G1R1c) characterised here matched those identified previously in diarrhoeic children in Wuhan.ConclusionsThis is the first molecular study reporting the genetic identity and prevalence of C. baileyi and C. meleagridis in chickens in Hubei. The findings suggest that C. meleagridis subtypes IIIbA26G1R1b and IIIbA22G1R1c are cross-transmissible between chickens and humans, raising awareness about the significance of birds as potential reservoirs of zoonotic variants of Cryptosporidium. Future studies might focus on investigating the prevalence of ‘zoonotic’ subtypes of Cryptosporidium meleagridis in various species of wild and domesticated birds, and on comparing them with those found in humans in China and other countries.

Molecular epidemiological survey and complete genomic phylogenetic analysis of H6 subtype avian influenza viruses in poultry in China from 2011 to 2016

To investigate the prevalence and evolution of the H6 subtype avian influenza viruses (AIVs) circulating in poultry in China from 2011 to 2016, 11 molecular epidemiological surveys was performed in this study. In total, 893 H6 subtype viral strains were isolated from 67,639 swab samples and 360 environmental samples. From these strains, 35 representative strains were selected and their whole genomic sequences determined. According to a phylogenetic analysis and molecular characterization, all 35 viral strains belonged to the Eurasian avian lineage. All of them were categorized as ‘low pathogenic’ and a few strains had some bioinformatical mutations. This epidemiological survey shows that the prevalence of H6 subtype AIVs increased from 2012 to 2016 in China, and suggests that infections by H6 subtype AIVs in China has increased in recent years.

Risk of tuberculosis transmission among healthcare workers.

Data from a prospective molecular-epidemiological study (1997–2015) of patients with culture-confirmed tuberculosis in Hamburg, Germany, were evaluated to assess the occupational risk of Mycobacterium tuberculosis complex transmission in a low-incidence setting.Isolates of M. tuberculosis complex were genotyped using IS6110 restriction fragment length polymorphism analysis. Results of structured questionnaires, geographical mapping and additional patient interviews were used for confirming epidemiological links.Out of the 2393 cases, 918 (38.4%) were classified into 224 clusters comprising 2–70 patients per cluster. Among the 918 cluster members, epidemiological links could be confirmed in 340 (37.0%) patients. In total, 55 (2.3%) patients were healthcare workers; 26 healthcare workers remained unclustered, but 29 healthcare workers belonged to cluster groups. Conventional contact tracing performed before genotyping to identify sources of the reported index cases detected only 73 (3.1%) patients.Logistic regression analysis confirmed work in the healthcare sector as strongest predictor for clustering of patients with verified epidemiological links (odds ratio (OR) 3.1, 95% CI 1.6–5.9), followed by alcoholism (OR 2.3, 95% CI 1.7–3.2) and sputum smear positivity (OR 1.8, 95% CI 1.4–2.3). Immigrants were more likely to be cluster nonmembers (OR 0.3, 95% CI 0.3–0.5). Recent transmission in Hamburg within the 19-year study period was found to be strongly associated with working in a healthcare facility. Although clusters also include many “imported” strains from abroad or regional highly prevalent M. tuberculosis strains with no evident epidemiological connection, routine molecular-epidemiological survey is indispensable to optimising and controlling the effectiveness of TB control strategies in German healthcare settings.

Molecular Epidemiological Survey of Leptospira Infection of Wild Rodents in the Urban Settlement of Cambodia.

Leptospirosis remains a major public health threat in Cambodia. In this study, we aimed at facilitating the development of preventive strategies against leptospirosis in Cambodia by conducting molecular epidemiological surveys of Leptospira infection among wild rodents. One hundred sixty-three wild rodents were captured in the capital Phnom Penh and surrounding areas, and their kidneys and bladders were collected for analysis. Identification of wild rodent species was determined by using the cytochrome c oxidase I gene. TaqMan PCR of the flagellin B gene (flaB) was performed to detect Leptospira, and species of the isolates were identified by flaB sequencing analysis. The species and respective number of rodents collected were as follows: Rattus norvegicus, 80 (49.1%); Rattus argentiventer, 53 (32.5%); Rattus exulans, 6 (3.7%); Rattus indica, 15 (9.2%); Maxomys surifer, 3 (1.8%); and Rattus sp., 6 (3.7%). Leptospira was detected in 20 out of the 163 rodents (12.3%) and was categorized as either Leptospira interrogans or Leptospira noguchii. R. norvegicus had the highest prevalence of Leptospira (17.5%), and R. argentiventer and Rattus sp. showed infection rates of 9.4% and 16.7%, respectively. Based on these results, wild rodents living in urban areas of Cambodia were found to be important reservoirs of highly virulent Leptospira. The flaB sequence results of our study provided information regarding the prevalence of Leptospira species, which was dependent on the rodent species. This study is the first study on leptospirosis in wild rodents in the urban areas of Cambodia, where there is limited information on leptospirosis.

Molecular epidemiological survey of canine parvovirus in domestic dogs in four provinces, China

Canine parvovirus (CPV) can cause severe disease in animals, especially in dogs, and continuously generates new variants. In this study, the complete VP2 genes of 59 CPV isolates from clinical diseased dogs between 2015 and 2016 in 4 Chinese provinces were sequenced and analyzed. The results showed that new CPV-2a was still the prominent CPV genotype, followed by CPV-2c and new CPV-2b. CPV-2c with Ala5Gly and Gln370Arg mutations was first detected in Henan, Guangxi and Jiangsu provinces in China. A phylogenetic tree based on VP2 sequences showed that all isolates in this study formed a close lineage which separated from foreign isolates. The above results indicated that point mutations in VP2 were constantly occurring along with the widespread of CPV in China.