Human Infections In China Research Articles

Prevalence and genetic characteristics of Cryptosporidium, Enterocytozoon bieneusi and Giardia duodenalis in cats and dogs in Heilongjiang province, China

This study investigated 319 fecal specimens of cats (n=52) and dogs (n=267) from Heilongjiang province, China for the prevalence and genetic characteristics of Cryptosporidium, Enterocytozoon bieneusi, and Giardia duodenalis. PCR and DNA sequence analysis of the small subunit rRNA gene identified C. felis and C. parvum in one cat each (3.8%) and C. canis and C. ubiquitum in 6 dogs (2.2%). Polymorphisms in the ribosomal internal transcribed spacer and phylogenetic analysis characterized zoonotic E. bieneusi genotypes D, EbpC, NED1, and NED2 and host-adapted ones NED3, NED4, and PtEb IX in 18 dogs (6.7%) and human-pathogenic genotypes D and IV in 3 cats (5.8%). Genotyping based on the hypermutation of G. duodenalis triosephosphate isomerase gene (TPI) facilitated identification of assemblage F in a cat (1.9%) and assemblages C and E in 12 dogs (4.5%). Subtypes of G. duodenalis isolates were determined by measuring the diversity of both TPI nucleotide and amino acid sequences. C. canis, C. felis, C. parvum, E. bieneusi genotypes D, EbpC, and IV, and G. duodenalis assemblage C identified herein have been documented in human infections in China. C. canis, C. parvum, C. ubiquitum, and E. bieneusi genotypes D, EbpC, and IV carried by cats or dogs also existed in wastewater in China. The finding suggested pet animals could be reservoirs for human cryptosporidiosis, microsporidiosis, and giardiasis and potential sources of water contamination in China.

Genetic Diversity of Avian Influenza A (H10N8) Virus in Live Poultry Markets and Its Association with Human Infections in China

Following the first human infection with the influenza A (H10N8) virus in Nanchang, China in December 2013, we identified two additional patients on January 19 and February 9, 2014. The epidemiologic, clinical, and virological data from the patients and the environmental specimen collected from 23 local live poultry markets (LPMs) were analyzed. The three H10N8 cases had a history of poultry exposure and presented with high fever (>38°C), rapidly progressive pneumonia and lymphopenia. Substantial high levels of cytokines and chemokines were observed. The sequences from an isolate (A/Environment/Jiangxi/03489/2013 [H10N8]) in an epidemiologically linked LPM showed highly identity with human H10N8 virus, evidencing LPM as the source of human infection. The HA and NA of human and environmental H10N8 isolates showed high identity (99.1–99.9%) while six genotypes with internal genes derived from H9N2, H7N3 and H7N9 subtype viruses were detected in environmental H10N8 isolates. The genotype of the virus causing human infection, Jiangxi/346, possessed a whole internal gene set of the A/Environment/Jiangxi/10618/2014(H9N2)-like virus. Thus, our findings support the notion that LPMs can act as both a gene pool for the generation of novel reassortants and a source for human infection, and intensive surveillance and management should therefore be conducted.

In vitro Transcriptome Analysis of Two Chinese Isolates of Streptococcus suis Serotype 2

The Streptococcus suis serotype 2 (S. suis 2) isolates 05ZYH33 and 98HAH33 have caused severe human infections in China. Using a strand-specific RNA-seq analysis, we compared the in vitro transcriptomes of these two Chinese isolates with that of a reference strain (P1/7). In the 89K genomic island that is specific to these Chinese isolates, a toxin–antitoxin system showed relatively high levels of transcription among the S. suis. The known virulence factors with high transcriptional activity in these two highly-pathogenic strains are mainly involved in adhesion, biofilm formation, hemolysis and the synthesis and transport of the outer membrane protein. Furthermore, our analysis of novel transcripts identified over 50 protein-coding genes with one of them encoding a toxin protein. We also predicted over 30 small RNAs (sRNAs) in each strain, and most of them are involved in riboswitches. We found that six sRNA candidates that are related to bacterial virulence, including cspA and rli38, are specific to Chinese isolates. These results provide insight into the factors responsible for the difference in virulence among the different S. suis 2 isolates.

Cryptosporidium andersoni as a novel predominant Cryptosporidium species in outpatients with diarrhea in Jiangsu Province, China.

BackgroundCryptosporidium hominis and C. parvum are usually considered to be the major pathogens responsible for human cryptosporidiosis. However, there have been few studies regarding the molecular epidemiology of Cryptosporidium in human infections in China. Here we investigated Cryptosporidium infection in patients with diarrhea, in Danyang Hospital of Jiangsu Province, China, at the genotype level.MethodsA total of 232 stool specimens were collected from outpatients with diarrhea in Danyang Hospital of Jiangsu Province, China, from February 2012 to January 2013. Each specimen was stained from direct fecal smears and examined for Cryptosporidium using modified acid fast staining and microscopy. Moreover, genomic DNA of each fecal sample was screened for the presence of Cryptosporidium with nested PCR, which was genotyped by analyzing the DNA sequences of small subunit rRNA (SSU rRNA).ResultsThe average infection rate of Cryptosporidium was 1.3% (3/232) by microscopy and subjected to PCR amplification of the SSU rRNA gene of Cryptosporidium, with 9.91% (23/232) being positive for Cryptosporidium with a significant peak in autumn. Based on the SSU rRNA gene, two Cryptosporidium spp. were identified, including C. andersoni (n =21) and C. hominis (n =2). Two types of C. andersoni, designated as A370+ and A370- , were found in the SSU rRNA gene in our present study, which was 100% homologous to C. andersoni infections derived from dairy calves and goats, respectively. The clinical questionnaires showed no significant difference in age, gender and frequency of diarrhea, but duration of diarrhea was shorter for C. andersoni than that of C. hominis (mean, 2 vs. 4 days; p <0.01).ConclusionsC. andersoni is the dominant species in Danyang City of Jiangsu Province. The fact that SSU rRNA sequences of C. andersoni obtained from human stools exhibited 100% homologous to those derived from dairy calves and goats supported that C. andersoni infection might be attributable to animal origin. The difference in the duration of diarrhea of C. andersoni and C. hominis indicated that different Cryptosporidium species might cause different clinical manifestations.

Songbirds and Parakeets: Possible Sources of Influenza A (H7N9) Virus Transmission

Avian-origin influenza A (H7N9) virus continues to cause sporadic human infections in China; older men have experienced disproportionate rates of

Dynamic reassortments and genetic heterogeneity of the human-infecting influenza A (H7N9) virus

Influenza A (H7N9) virus has been causing human infections in China since February 2013, raising serious concerns of potential pandemics. Previous studies demonstrate that human infection is directly linked to live animal markets, and that the internal genes of the virus are derived from H9N2 viruses circulating in the Yangtze River Delta area in Eastern China. Here following analysis of 109 viruses, we show a much higher genetic heterogeneity of the H7N9 viruses than previously reported, with a total of 27 newly designated genotypes. Phylogenetic and genealogical inferences reveal that genotypes G0 and G2.6 dominantly co-circulate within poultry, with most human isolates belonging to the genotype G0. G0 viruses are also responsible for the inter- and intra-province transmissions, leading to the genesis of novel genotypes. These observations suggest the province-specific H9N2 virus gene pools increase the genetic diversity of H7N9 via dynamic reassortments and also imply that G0 has not gained overwhelming fitness and the virus continues to undergo reassortment.

The Schistosoma japonicum self-cure phenomenon in water buffaloes: potential impact on the control and elimination of schistosomiasis in China

Schistosomiasis japonica, caused by Schistosoma japonicum, is an important zoonotic disease in China, the Philippines and small pockets of Indonesia. In addition to infecting people, S. japonicum can infect over 40 species of wild and domestic animals which have varying impacts on human infection. It is now generally accepted that bovines, particularly water buffaloes, are the major reservoir for human infection in China as they are naturally infected with schistosomes and deposit more eggs into the environment than humans or any other animal host. This complicates control efforts and the economic burden associated with schistosomiasis morbidity and mortality has taken its toll on both human and livestock populations. Over the last 50years, the schistosomiasis control program in China has made great strides in reducing prevalence and morbidity, and the Chinese authorities now aim to eliminate the disease nationwide in the next decade. Current Chinese control strategies place particular importance on interventions targeting bovines including: praziquantel treatment, barrier farming to prevent grazing in transmission areas, their replacement with mechanized tractors and possible bovine vaccination. A number of studies have shown that in the period following S. japonicum infection, the worm burden drops sharply in water buffaloes and some other animal hosts such as pigs. This is due to a self-cure phenomenon whereby there is parasite clearance by both immune and non-immune factors. Here we review studies investigating the self-cure effect, paying particular attention to S. japonicum infection in water buffaloes, and discuss its potential impact on the future schistosomiasis control and elimination efforts in China. Further understanding of the mechanism of self-cure in water buffaloes could be important for future schistosome vaccine design and delivery.

Spatial and temporal analysis of human infection with avian influenza A(H7N9) virus in China, 2013

Descriptive and geographic information system methods were used to depict the spatial and temporal characteristics of the outbreak of human infection with a novel avian influenza A(H7N9) virus in mainland China, the peak of which appeared between 28 March and 18 April 2013. As of 31 May 2013, there was a total of 131 reported human infections in China, with a cumulative mortality of 29% (38/131). The outbreak affected 10 provinces, with 106 of the cases being concentrated in the eastern coastal provinces of Zhejiang, Shanghai and Jiangsu. Statistically significant spatial clustering of cumulative human cases was identified by the Cuzick–Edwards’ k-nearest neighbour method. Three spatio-temporal clusters of cases were detected by space–time scan analysis. The principal cluster covered 18 counties in Zhejiang during 3 to 18 April (relative risk (RR): 26.39;p<0.0001), while two secondary clusters in March and April covered 21 counties along the provincial boundary between Shanghai and Jiangsu (RR: 6.35;p<0.0001) and two counties in Jiangsu (RR: 72.48;p=0.0025). The peak of the outbreak was in the eastern coastal provinces of Zhejiang, Shanghai and Jiangsu that was characterised by statistically significant spatio-temporal aggregation, with a particularly high incidence in March and April 2013.

Pushing the Envelope on Cost/Benefit Analysis

BioTechniquesVol. 55, No. 3 From the EditorOpen AccessPushing the envelope on cost/benefit analysisNathan BlowNathan BlowBioTechniquesSearch for more papers by this authorPublished Online:3 Apr 2018https://doi.org/10.2144/000114068AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinkedInRedditEmail Today, whether we like it or not, there is a constant need to justify funding for cutting-edge research. Grant money is scarce, and thanks to the internet, journalists are reporting the latest discoveries faster than ever before, raising questions among the general public about the possible impact of these studies. It is with this in mind that I think we are reaching a crossroads in public perception—with research on the avian influenza virus H7N9 likely to take center stage.H7N9 has caused more than 130 human infections in China. Although the virus is not currently transmissible among humans, a team of researchers is suggesting that creating mutant viruses with different degrees of transmissibility in mammals will help us understand the potential for human-to-human transmission.In a letter published this August in both Science and Nature, 22 researchers from 12 universities in the the US, Europe, and Asia present a case for performing gain-of-function [GOF] experiments in H7N9 to examine immunogenicity, adaptation, drug resistance, transmission, and pathogenicity (1,2). The authors argue that “classical epidemiological tracking does not give public health authorities the time they need to mount an effective response to mitigate the effects of a pandemic virus. To provide information that can assist surveillance activities—thus enabling appropriate public health preparations to be initiated before a pandemic—experiments that may result in GOF are critical.”Such experiments could provide new insights into virus function and possible paths of future evolution resulting in increased transmissibility to humans. The challenge, though, is to monitor and report that progress as a growing range of mutations are engineered in the lab. Prior work by the same researchers examined the H5N1 virus and its capacity for airborne transmission between ferrets in the lab (3). This work was controversial, leading to several public discussions amongst government officials, researchers, and journal editors before that work was finally published.The rationale behind new GOF studies in H7N9 is curious. While planning ahead for a potential pandemic is important, are vaccine developers willing to design vaccines against “hypothetical” viruses based on GOF mutations? Actually, work has already begun on an H7N9 vaccine, so it is not clear what impact new GOF studies would have.While surveillance should be done, are GOF experiments really necessary given our current knowledge of the potential mechanisms by which viruses can acquire the ability to broaden their host range? Next-generation sequencing can decode a whole genome in a day, and airborne transmission can be determined quickly based on information from patients. Sequencing might not be a viable option in the developing world, so does the knowledge gained through GOF studies improve surveillance options? I'm not suggesting these questions could not be answered, rather I am echoing the need for greater transparency, as many have suggested.Researchers must go to extra lengths to accurately explain the rationale behind experiments that might create more transmissible viruses and how they will be safely conducted. A nice article in Nature Biotechnology suggesting a new safeguard mechanism for GOF studies was recently published (3). Here, the authors took advantage of endogenous miRNAs in human cells to prevent transmission of viruses. The technique appears effective and provides a degree of possible containment when working with GOF viruses. Such techniques and approaches need to be highlighted as widely as the letters suggesting these experiments in the first place.Hyperbole aside, this is a moment where scientists need to consider the psychological impact of their work on the general public. Fears about scientific experiments should not be used as a tool to get an experiment done or to stop such research altogether. There should not be any perception that scientists are simply creating a series of “monster viruses” that will be locked away in labs around the world; this only feeds public fears and future Hollywood movies. Providing clear explanations for the potential of such research, as well as the safeguards built into these studies, will help to reduce concerns and provide a stronger framework for experimental success.The H5N1 studies led to lengthy discussions on the cost/benefits of engineering influenza viruses. In the end, it was decided that the benefits outweighed the potential risks. Now, as researchers push the envelope once again, it is important to revisit that cost/benefit question. Share your thoughts with us at bioeditor@biotechniques.com.

The genesis and source of the H7N9 influenza viruses causing human infections in China.

A novel H7N9 influenza A virus first detected in March 2013 has since caused more than 130 human infections in China, resulting in 40 deaths. Preliminary analyses suggest that the virus is a reassortant of H7, N9 and H9N2 avian influenza viruses, and carries some amino acids associated with mammalian receptor binding, raising concerns of a new pandemic. However, neither the source populations of the H7N9 outbreak lineage nor the conditions for its genesis are fully known. Using a combination of active surveillance, screening of virus archives, and evolutionary analyses, here we show that H7 viruses probably transferred from domestic duck to chicken populations in China on at least two independent occasions. We show that the H7 viruses subsequently reassorted with enzootic H9N2 viruses to generate the H7N9 outbreak lineage, and a related previously unrecognized H7N7 lineage. The H7N9 outbreak lineage has spread over a large geographic region and is prevalent in chickens at live poultry markets, which are thought to be the immediate source of human infections. Whether the H7N9 outbreak lineage has, or will, become enzootic in China and neighbouring regions requires further investigation. The discovery here of a related H7N7 influenza virus in chickens that has the ability to infect mammals experimentally, suggests that H7 viruses may pose threats beyond the current outbreak. The continuing prevalence of H7 viruses in poultry could lead to the generation of highly pathogenic variants and further sporadic human infections, with a continued risk of the virus acquiring human-to-human transmissibility.

H7N9 influenza-the laboratory presentations: A letter to editor

Influenza virus infection is an important group of respiratory infectious disease. Several groups of influenza viruses can cause human infections. However, in the recent years, there are many newly emerging influenza infections, which have never been previously seen in human. Crossing species from animal to human lead to new emerging zoonosis. Those new influenza infections are considered atypical influenza infections and have the trend of worldwide expansion[1],[2]. H5N1 bird flu and H1N1 swine flu are good examples of new emerging influenza infections[3],[4]. However, present hottest concern is on the new H7N9 bird flu[5]–[7]. In fact, H7N9 influenza is the known virus causing avian disease[8],[9]. However, the observation of human infection in China is the first description in human, hence, it is mentioned as the newest emerging infection of the world[5],[6]. Due to the nature of a new emerging infection, lack of knowledge on H7N9 influenza can be expected and this is the point for further study. In this specific article, the author discusses on the laboratory presentations of new H7N9 influenza infection, which has just been described for a few months (first observed in February 2013)[5],[6]. Firstly, the pathogen was not identified. However, the pathogenic agent was finally detected as a newly identified human influenza virus, H7N9[10],[12].

Risk assessment of human infection with a novel bunyavirus in China

To assess the public health risk of human infection from a novel bunyavirus - severe fever with thrombocytopenia syndrome virus (SFTSV) - in China. The likelihood of disease spread and the magnitude of public health impact were assessed to clarify overall risk. Literature about hazard, exposure and contextual factors associated with SFTSV infection was collected and reviewed. Information on SFTSV cases and the population in six provinces under surveillance was compared. SFTSV is a member of the Phlebovirus genus of the Bunyaviridae family. A widely distributed tick species, Haemaphysalis longicornis, can act as the vector; thus the disease is likely to spread in China. Symptoms of SFTSV infection are nonspecific, but have led to multiorgan dysfunction in severe cases. High-risk populations include farmers and older females. Evidence of human-to-human transmission within family and hospital has been reported. The capacity for treatment and diagnosis of SFTSV are adequate in rural communities in China, and community awareness of the disease should be high. There is a low to moderate public health risk related to SFTSV human infection in China. There is potential for an increase in the number of cases reported as awareness increases and when surveillance is expanded.

Immunodiagnostic efficacy of detection of Schistosoma japonicum human infections in China: a meta analysis

Objective To assess the diagnostic efficacy of the currently most widely used indirect hemagglutination assay (IHA) and enzyme-linked immunosorbent assay (ELISA) for detection of Schistosoma japonicum human infections. Methods A comprehensive search was undertaken from China National Knowledge Infrastructure, Wanfang Database, VIP Database, PubMed, Cochrane Library, Science Citation Index Expanded, Proquest, and the inclusion and exclusion criteria were strictly settled. The funnel plot was used to assess the publication bias, Cochran's Q test was employed to measure the homogeneity between studies, a summary receiver operating characteristic (SROC) curve was used to compare the diagnostic accuracy between the IHA and ELISA qualitatively by means of the Weighted Least Square method, the Ordinary Least Square method and the Robust regression method, and the diagnostic odds ratio (DOR) was drawn to compare the accuracy quantitatively. Results Out of 785 publications, 19 papers were eventually selected for analysis. Literature quality assessment indicated that minor publication bias existed in studies pertaining IHA test, but no bias was found in literatures regarding ELISA test. The heterogeneity test showed a heterogeneity between studies was present (χ 2=466.07 and 34.67, both P values<0.0001). The areas under the SROC curves of IHA were all higher than that of ELISA test using the three methods (Weighted Least Square method: 0.766 vs. 0.695, Ordinary Least Square method: 0.826 vs. 0.741, Robust regression: 0.815 vs. 0.715). The TPR* values for IHA and ELISA were 0.710, 0.759, 0.749, and 0.650, 0.686 and 0.666, respectively, and OR values were 5.997, 9.937, 8.893, and 3.432, 4.784 and 3.959, respectively. The DOR of IHA was 9.41 (95% CI: 4.88-18.18), and 4.78 (95% CI: 3.21-7.13) for ELISA. Conclusions All above results revealed that the diagnostic performance of IHA is better than that of ELISA. However, taking into account their unsatisfactory diagnostic value in areas with low infection intensity, a search for a better diagnostic test that can be applied in field situations in China should be given high priority.

GI‐type T4SS‐mediated horizontal transfer of the 89K pathogenicity island in epidemic Streptococcus suis serotype 2

Pathogenicity islands (PAIs), a distinct type of genomic island (GI), play important roles in the rapid adaptation and increased virulence of pathogens. 89K is a newly identified PAI in epidemic Streptococcus suis isolates that are related to the two recent large-scale outbreaks of human infection in China. However, its mechanism of evolution and contribution to the epidemic spread of S. suis 2 remain unknown. In this study, the potential for mobilization of 89K was evaluated, and its putative transfer mechanism was investigated. We report that 89K can spontaneously excise to form an extrachromosomal circular product. The precise excision is mediated by an 89K-borne integrase through site-specific recombination, with help from an excisionase. The 89K excision intermediate acts as a substrate for lateral transfer to non-89K S. suis 2 recipients, where it reintegrates site-specifically into the target site. The conjugal transfer of 89K occurred via a GI type IV secretion system (T4SS) encoded in 89K, at a frequency of 10−6 transconjugants per donor. This is the first demonstration of horizontal transfer of a Gram-positive PAI mediated by a GI-type T4SS. We propose that these genetic events are important in the emergence, pathogenesis and persistence of epidemic S. suis 2 strains.

Isolation and Genetic Characteristics of Human Genotype 1 Japanese Encephalitis Virus, China, 2009

BackgroundSeveral studies have shown that the predominant genotype of Chinese Japanese encephalitis virus (JEV) is evolving from genotype 3 to genotype 1. However, in recent years, almost all genotype 1 isolates were from mosquitoes, and genotype 1 has been less associated with human disease than genotype 3. This study reports the isolation of human genotype 1 JEV and its genetic characteristics to provide additional insights into human JE pathogens that are currently circulating in China.Methods and ResultsIn 2009, 31 cerebrospinal fluid samples were collected from patients living in Yunnan and Shanxi provinces and were used to inoculate Aedes albopictus C6/36 cells for virus isolation. The JEV strains were identified using immunofluorescent assays and the reverse transcription-polymerase chain reaction. Phylogenetic analyses based on the partial capsid/pre-membrane and full envelope (E) sequences were performed using Clustalx 1.8 software. Three JEV isolates were obtained from a 4-year-old girl and a 2-year-old boy living in Yunnan and an 82-year-old woman in Shanxi. The boy had been immunized with one dose of JE live attenuated vaccine. New isolates were grouped into genotype 1. Amino acid sequence for the viral E protein indicated 95% to 100% identity with each other and with other JEV strains. When compared with a consensus sequence of E protein, two amino acid substitutions were found: SerE-123-Asn in the two Yunnan isolates and LysE-166-Arg in the Shanxi isolate.ConclusionsOur findings indicate that the genotype 1 of JEV is causing human infections in China. Our observation of a previously vaccinated boy developing JE from genotype 1 virus infection also calls for more detailed studies, both in vitro and in vivo neutralization tests as well as active surveillance, to examine the possibility of a lack of complete protection conferred by the live attenuated JE vaccine against genotype 1 virus.

Emergence and predominance of an H5N1 influenza variant in China.

The development of highly pathogenic avian H5N1 influenza viruses in poultry in Eurasia accompanied with the increase in human infection in 2006 suggests that the virus has not been effectively contained and that the pandemic threat persists. Updated virological and epidemiological findings from our market surveillance in southern China demonstrate that H5N1 influenza viruses continued to be panzootic in different types of poultry. Genetic and antigenic analyses revealed the emergence and predominance of a previously uncharacterized H5N1 virus sublineage (Fujian-like) in poultry since late 2005. Viruses from this sublineage gradually replaced those multiple regional distinct sublineages and caused recent human infection in China. These viruses have already transmitted to Hong Kong, Laos, Malaysia, and Thailand, resulting in a new transmission and outbreak wave in Southeast Asia. Serological studies suggest that H5N1 seroconversion in market poultry is low and that vaccination may have facilitated the selection of the Fujian-like sublineage. The predominance of this virus over a large geographical region within a short period directly challenges current disease control measures.