Over the course of two waves of infection, H7N9 avian influenza A virus has caused 436 human infections and claimed 170 lives in China as of July 2014. To investigate the prevalence and genetic diversity of H7N9, we surveyed avian influenza viruses in poultry in Jiangsu province within the outbreak epicenter. We found frequent occurrence of H7N9/H9N2 coinfection in chickens. Molecular clock phylogenetic analysis confirms coinfection by H7N9/H9N2 viruses and also reveals that the identity of the H7N9 outbreak lineage is confounded by ongoing reassortment between outbreak viruses and diverse H9N2 viruses in domestic birds. Experimental inoculation of a coinfected sample in cell culture yielded two reassortant H7N9 strains with polymerase segments from the original H9N2 strain. Ongoing reassortment between the H7N9 outbreak lineage and diverse H9N2 viruses may generate new strains with the potential to infect humans, highlighting the need for continued viral surveillance in poultry and humans.
IMPORTANCE We found frequent occurrence of H7N9/H9N2 coinfection in chickens. The H7N9 outbreak lineage is confounded by ongoing reassortment between H7N9 and H9N2 viruses. The importance of H9N2 viruses as the source of novel avian influenza virus infections in humans requires continuous attention.
subtype H7N9 virus; influenza A(H7N9) virus; H7N9; influenza; avian influenza; viruses; human-to-human transmission; human; close contacts; seroepidemiology; China
Babesia venatorum; parasites; protozoa; human infection; child; ticks; zoonoses; China
We used molecular methods to identify Rickettsia raoultii infections in 2 persons in China. These persons had localized rashes around sites of tick bites. R. raoultii DNA was detected in 4% of Dermacentor silvarum ticks collected in the same area of China and in 1 feeding tick detached from 1 patient.
Rickettsia raoultii; rickettsia; human infections; ticks; Dermacentor silvarum; vector-borne infections; China
Human adenovirus 55 (HAdV-55) has caused recent outbreaks of acute respiratory disease (ARD) among adults and military trainees. The active surveillance for HAdV infections was sparse in China, and current knowledge on the HAdV-type distributions and its molecular evolution is lacking.
To acquire better understanding on the prevalence and molecular evolution of HAdV-55 strains in China, for an informed strategy for disease control and prevention.
Nasopharyngeal aspirates were collected from hospitalized children with ARTI in Chongqing during 2009–2012. The genotype of HAdV isolates were determined by sequencing the partial hexon and fiber genes. Whole genome sequences of HAdV-55 were obtained for molecular evolution analysis.
About 191 (8·55%) HAdV were detected in 2234 children, including 92 (48·2%) with HAdV-7, 72 (37·7%) with HAdV-3, 6 (3·1%) with HAdV-55, 5 (2·6%) with HAdV-5, 4 (2·1%) with HAdV-1, 1 (0·5%) with HAdV-2, and 11(5·8%) with untyped HAdV. Four of these children developed pneumonia, two of whom were diagnosed with severe pneumonia and/or encephalopathy. HAdV-55 isolates clustered with HAdV-11 sequences based on the hexon gene and clustered with HAdV-14 sequences based on the fiber gene and the whole genome. The overall evolutionary rates of hexon gene, fiber gene, and whole genome of HAdV-55 were estimated at 6·2 × 10−5 s/s/y, 8·0 × 10−5 s/s/y, and 1·7 × 10−5 s/s/y, respectively.
This study suggested HAdV-55 as an emerging infectious disease pathogen has conserved genetic structure and is closely related to each other. Further molecular investigation based on HAdV-55 of wider origin might facilitate understanding its diversity, dissemination, and transmission in China.
Acute respiratory disease; children; China; human adenovirus
We report here the genome sequence of Borrelia afzelii strain HLJ01, isolated from a patient with Lyme disease in China. It is the first report of the whole genome of a B. burgdorferi sensu lato isolate from a human in China.
We detected Bartonella quintana in 48.6% of captive rhesus macaques from an animal facility in Beijing, China. Prevalence of infection increased over the period of observation. Our findings suggest that macaques may serve as reservoir hosts for B. quintana and that Pedicinus obtusus lice might act as efficient vectors.
Bartonella quintana; rhesus macaques; reservoir host; lice; transmission; China; vector-borne infections; Bartonella
To identify Candidatus Neoehrlichia mikurensis infection in northeastern China, we tested blood samples from 622 febrile patients. We identified in 7 infected patients and natural foci for this bacterium. Field surveys showed that 1.6% of ticks and 3.8% of rodents collected from residences of patients were also infected.
Candidatus Neoehrlichia mikurensis; bacteria; human infection; ticks; rodents; vector-borne infections; China
Data from all reported cases of 2009 pandemic influenza A (H1N1) were obtained from the China Information System for Disease Control and Prevention. The spatiotemporal distribution patterns of cases were characterized through spatial analysis. The impact of travel-related risk factors on invasion of the disease was analyzed using survival analysis, and climatic factors related to local transmission were identified using multilevel Poisson regression, both at the county level. The results showed that the epidemic spanned a large geographic area, with the most affected areas being in western China. Significant differences in incidence were found among age groups, with incidences peaking in school-age children. Overall, the epidemic spread from southeast to northwest. Proximity to airports and being intersected by national highways or freeways but not railways were variables associated with the presence of the disease in a county. Lower temperature and lower relative humidity were the climatic factors facilitating local transmission after correction for the effects of school summer vacation and public holidays, as well as population density and the density of medical facilities. These findings indicate that interventions focused on domestic travel, population density, and climatic factors could play a role in mitigating the public health impact of future influenza pandemics.
China; disease outbreaks; disease transmission, infectious; influenza, human; invasion process; pandemics
Hemorrhagic fever with renal syndrome (HFRS) is an important public health problem in Shandong Province, China. In this study, we combined ecologic niche modeling with geographic information systems (GIS) and remote sensing techniques to identify the risk factors and affected areas of hantavirus infections in rodent hosts. Land cover and elevation were found to be closely associated with the presence of hantavirus-infected rodent hosts. The averaged area under the receiver operating characteristic curve was 0.864, implying good performance. The predicted risk maps based on the model were validated both by the hantavirus-infected rodents' distribution and HFRS human case localities with a good fit. These findings have the applications for targeting control and prevention efforts.
Anaplasma phagocytophilum; ticks; bacteria; China; Russia; border; letter
To elucidate the importance of the norovirus and other enteric viruses, and the difference of the genetic relatedness on norovirus between the outbreak and sporadic cases, a total of 557 stool samples, consisting of 503 sporadic cases and 54 samples of 4 outbreaks were collected and tested for norovirus and other enteric viruses in Beijing, China, July 2007–June 2008. The data showed norovirus, rotavirus, astrovirus, and sapovirus, were detected in 26.6%, 6.1%, 1.8%, and 0.5%, respectively. Norovirus was detected almost throughout the surveillance period, norovirus co-infecting with rotavirus, astrovirus, and sapovirus, respectively, were identified both in outbreak and the sporadic cases. GII.4/2006 was identified as the predominant strain circulating both in outbreak and sporadic cases. The results showed that norovirus was rather the important agent than other enteric viruses affected adults with acute gastroenteritis; no significant genetic relatedness of the dominant strains was found between the outbreak and sporadic cases.
Brucellosis; Brucella spp.; China; bacteria; zoonoses; letter
Roseomonas; bacteria; ticks; Dermacentor nuttalli; China; letter
Three strains were isolated and characterized.
To characterize the strains of Anaplasma phagocytophilum in wild and domestic animals in China, we isolated the organism from rodents and sheep in northeastern China. We isolated 3 strains (2 from rodents and 1 from sick sheep) through propagation in BALB/c mice and then cell culture in HL60 cells. The 3 isolates were identified by Wright-Giemsa staining, immunofluorescence, and electronic microscopy and were characterized by sequence analyses of the 16S rRNA gene, partial citrate synthase gene, major surface protein 4 gene, and heat shock protein gene. The multiple sequences of the 3 isolates were identical to each other but different from all known strains from other countries. The public health and veterinary relevance of the isolates deserves further investigation.
Anaplasma phagocytophilum; isolation; rodents; sheep; China; rickettsia; research
Influenza; seasonal pattern; surveillance; viruses; letter
Many rodent species may be involved in the enzootic maintenance of these agents.
A total of 705 rodents from 6 provinces and autonomous regions of mainland People’s Republic of China were tested by PCRs for tick-borne agents (Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, spotted fever group rickettsiae, and Francisella tularensis). Infection rates were 5.5%, 6.7%, 9.1% and 5.0%, respectively. Eighteen (2.6%) rodents of 10 species were positive for 2 or 3 agents. Sequence analysis of PCR products confirmed the presence and genotypes of detected agents. These findings demonstrate that these tick-borne agents cocirculate and that a variety of rodent species may be involved in their enzootic maintenance.
Anaplasma phagocytophilum; Borrelia burgdorferi sensu lato; spotted fever group rickettsiae; Francisella tularensis; rodents; coexistence; China; research
Population fluctuation is a risk factor for TB in Beijing.
To determine the role of the migrant population in the transmission of tuberculosis (TB), we investigated the distribution and magnitude of TB in permanent residents and migrant populations of Beijing, People’s Republic of China, from 2000 through 2006. An exploratory spatial data analysis was applied to detect the “hot spots” of TB among the 2 populations. Results, using the data obtained from 2004–2006, showed that people who migrated from the western, middle, and eastern zones of China had a significantly higher risk of having TB than did permanent residents. These findings indicate that population fluctuations have affected the rate of TB prevalence in Beijing, and interventions to control TB should include the migrant population.
pulmonary tuberculosis; migrant population; spatial analysis; Extra Poisson model; research
Hemorrhagic fever with renal syndrome (HFRS) is an important public health problem in the People’s Republic of China, accounting for 90% of human cases reported globally. In this study, a landscape epidemiologic approach, combined with geographic information system and remote sensing techniques, was applied to increase our understanding of HFRS due to Hantaan virus and its relationship with landscape elements in China. The landscape elements considered were elevation, normalized difference vegetation index (NDVI), precipitation, annual cumulative air temperature, land surface temperature, soil type, and land use. Multivariate logistic regression analysis showed that HFRS incidence was remarkably associated with elevation, NDVI, precipitation, annual cumulative air temperature, semihydromorphic soils, timber forests, and orchards. These findings have important applications for targeting HFRS interventions in mainland China.
Landscape elements; hemorrhagic fever with renal syndrome (Apodemus type); remote sensing; GIS; research
Eschars can be used for genetic characterization of O. tsutsugamushi during the convalescent phase.
To verify the value of eschars for the diagnosis of scrub typhus and to characterize genotypes of Orientia tsutsugamushi in patients, we examined eschars and blood specimens of 7 patients from Shandong Province, People's Republic of China, for O. tsutsugamushi by polymerase chain reaction targeting the Sta56 gene. All 7 eschars and acute-phase blood samples were positive, while no specific DNA amplicons were obtained from the 7 convalescent-phase blood samples collected after antimicrobial drug therapy. The findings indicate that patients' eschars can be used for detection and genetic characterization of O. tsutsugamushi during the convalescent phase.
Scrub typhus; eschar; Orientia tsutsugamushi
A total of 420 rodents in China were examined for Francisella tularensis by polymerase chain reaction. The infection rates were 4.76% in total, and 11.65%, 10.00%, 6.56%, 1.77%, and 0% in Jilin, Xinjiang, Heilongjiang, Inner Mongolia, and Zhejiang, respectively. Sequence analysis showed that all the detected agents belonged to F. tularensis subsp. holarctica.
Francisella tularensis; tularemia; PCR; rodents; China; dispatch
SARS; People’s Republic of China; pulmonary tuberculosis; letter
Viral adaptation to the host may be occurring under selective immune pressure.
Single nucleotide variations (SNVs) at 5 loci (17564, 21721, 22222, 23823, and 27827) were used to define the molecular epidemiologic characteristics of severe acute respiratory syndrome–associated coronavirus (SARS-CoV) from Beijing patients. Five fragments targeted at the SNV loci were amplified directly from clinical samples by using reverse transcription–polymerase chain reaction (RT-PCR), before sequencing the amplified products. Analyses of 45 sequences obtained from 29 patients showed that the GGCTC motif dominated among samples collected from March to early April 2003; the TGTTT motif predominanted afterwards. The switch from GGCTC to TGTTT was observed among patients belonging to the same cluster, which ruled out the possibility of the coincidental superposition of 2 epidemics running in parallel in Beijing. The Beijing isolates underwent the same change pattern reported from Guangdong Province. The same series of mutations occurring in separate geographic locations and at different times suggests a dominant process of viral adaptation to the host.
severe acute respiratory syndrome; molecular epidemiology; single nucleotide variation; RT-PCR, research
This study investigated the long-term excretion of severe acute respiratory syndrome–associated coronavirus in sputum and stool specimens from 56 infected patients. The median (range) duration of virus excretion in sputa and stools was 21 (14–52) and 27 (16–126) days, respectively. Coexisting illness or conditions were associated with longer viral excretion in stools.
Dispatch; Severe acute respiratory syndrome; epidemiology; cohort; transmission; diagnosis; RT-PCR
The rapid emergence, spread, and disease severity of avian influenza A(H7N9) in China has prompted concerns about a possible pandemic and regional spread in the coming months. The objective of this study was to predict the risk of future human infections with H7N9 in China and neighboring countries by assessing the association between H7N9 cases at sentinel hospitals and putative agricultural, climatic, and demographic risk factors.
This cross-sectional study used the locations of H7N9 cases and negative cases from China’s influenza-like illness surveillance network. After identifying H7N9 risk factors with logistic regression, we used Geographic Information Systems (GIS) to construct predictive maps of H7N9 risk across Asia.
Live bird market density was associated with human H7N9 infections reported in China from March-May 2013. Based on these cases, our model accurately predicted the virus’ spread into Guangxi autonomous region in February 2014. Outside China, we find there is a high risk that the virus will spread to northern Vietnam, due to the import of poultry from China.
Our risk map can focus efforts to improve surveillance in poultry and humans, which may facilitate early identification and treatment of human cases.
chickens; influenza in birds; influenza A virus – H7N9 subtype; international health problems; surveillance