Chengliang Chai

Systematic review of severe fever with thrombocytopenia syndrome: virology, epidemiology, and clinical characteristics.

Severe fever with thrombocytopenia syndrome (SFTS) was firstly discovered in China in 2010, followed by several reports from many other countries worldwide. SFTS virus (SFTSV) has been identified as the causative agent of the disease and has been recognized as a public health threat. This novel Bunyavirus belongs to the Phlebovirus genus in the family Bunyaviridae. This review also describes the different aspects of virology, pathogenesis, epidemiology, and clinical symptoms on the basis of the published article surveillance data and phylogenetic analyses of viral sequences of large, medium, and small segments retrieved from database using mega 5.05, simplot 3.5.1, network 4.611, and epi information system 3.5.3 software. SFTS presents with fever, thrombocytopenia, leukocytopenia, and considerable changes in several serum biomarkers. The disease has 10 ~ 15% mortality rate, commonly because of multiorgan dysfunction. SFTSV is mainly reported in the rural areas of Central and North‐Eastern China, with seasonal occurrence from May to September, mainly targeting those of ≥50 years of age. A wide range of domesticated animals, including sheep, goats, cattle, pigs, dogs, and chickens have been proven seropositive for SFTSV. Ticks, especially Haemaphysalis longicornis, are suspected to be the potential vector, which have a broad animal host range in the world. More studies are needed to elucidate the vector–animal–human ecological cycle, the pathogenic mechanisms in high level animal models and vaccine development.

Epidemiological characteristics of severe fever with thrombocytopenia syndrome in Zhejiang Province, China

OBJECTIVES To summarize the epidemiological characteristics of severe fever with thrombocytopenia syndrome (SFTS) in Zhejiang Province, China. METHODS A standardized questionnaire was used to collect information on demographic features, exposure history, clinical symptoms, and timelines of medical visits. Descriptive statistics were used to analyze the characteristics of SFTS. RESULTS A total of 65 cases of SFTS were identified in Zhejiang Province from 2011 to 2013, of whom 34 were male and 31 were female. The median age was 66 years and 60 cases occurred in persons aged ≥ 50 years. The majority (91%) of SFTS cases occurred between May and August. With regard to exposure history, patients had pursued outdoor activities (63%), had a history of exposure to a tick (68%) or tick bite (29%), bred domestic animals (31%), or had a history of exposure to a mouse (57%), and some patients had a multi-exposure history. Approximately 98.46% of patients were hospitalized, and symptoms of the illness included fever (98%), fatigue (71%), chills (51%), etc. Two family clusters occurred, although there was no person-to-person transmission. CONCLUSIONS In Zhejiang Province, SFTS is prevalent between May and August among elderly persons who live in hilly areas, and clinical features are not specific. More emphasis should be given to this disease and further training of medical personnel should be carried out to prevent misdiagnosis.

DETECTION OF BARTONELLA SPECIES IN SMALL MAMMALS FROM ZHEJIANG PROVINCE, CHINA

To estimate the prevalence of Bartonella in small mammals of different species, during different seasons, and at different study sites, and to provide baseline data for the risk assessment of human Bartonella infection, we captured small mammals using snap traps in Zhejiang Province, China. Bartonella species were detected in small-mammal samples by polymerase chain reaction and positive amplicons were sequenced. Bartonella DNA was detected in 47% (90/192) of Apodemus agrarius, 31% (14/45) of Rattus losea, 16% (7/43) of Rattus norvegicus, 24% (9/37) of Eothenomys melanogaster, 4% (1/28) of Niviventer confucianus, 30% (7/23) of Suncus murinus, 22% (2/9) of Microtus fortis, 27% (2/7) of Rattus tanezumi, and 29% (2/7) of Apodemus peninsulae. No Bartonella DNA was detected in 27 unidentified Soricidae or nine Mus musculus. This is the first report of Bartonella DNA detected in E. melanogaster and N. confucianus. The prevalence of Bartonella DNA varied among small-mammal species, study sites, and seasons; the prevalence of Bartonella DNA between genders did not vary significantly within a species. The sequences we report were most similar to Bartonella grahamii.

Epidemiology of human infections with avian influenza A(H7N9) virus in the two waves before and after October 2013 in Zhejiang province, China

We compared the epidemiological and clinical features of avian influenza A(H7N9) virus infections in the population in Zhejiang province, China, between March and April 2013 (first wave) and October 2013 and February 2014 (second wave). No statistical difference was found for age, sex, occupation, presence of underlying conditions, exposure history, white blood cell count, lymphocyte percentage and illness timeline and duration (all P > 0.05). The virus spread to 30 new counties compared to the first wave. The case-fatality rate was 22% in the first wave and 42% in the second (P = 0.023). Of those infected, 66% in the first wave and 62% in the second wave had underlying conditions. The proportion of those exposed to live poultry markets were 80% and 66%, respectively. We recommend permanent closure of live poultry markets and reformation of poultry supply and sales.

The first avian influenza A (H7N9) viral infection in humans in Zhejiang Province, China: a death report.

This study reports the first death caused by a novel avian influenza A (H7N9) virus in Zhejiang Province, China. The patient had chronic hepatitis B and history of exposure to poultry. The patient initially complained of diarrhea and influenza-like symptoms on March 7 and 14 respectively. The disease progressed to severe pneumonia, sustained hypoxia, and coagulation abnormalities. The patient died on March 27 because of respiratory failure, multiple organ failure, and disseminated intravascular coagulation without oseltamivir treatment. This H7N9 virus from Zhejiang is highly similar to isolates obtained from Shanghai, Jiangsu, Anhui, etc. Analysis of hemagglutinin, neuramidinase, and matrix genes indicated that the isolates share the same avian origin, have low virulence, and are sensitive to oseltamivir, but are resistant to adamantine. Only the isolate that caused the fatality exhibited substitution of Q226I in the HA gene, which indicates a potentially enhanced human affinity. The secondary transmission rate was 1.6% (2/125). Only two health workers presented with influenza-like symptoms, and they subsequently tested negative for H7N9 RNA. In conclusion, underlying disease, late diagnosis, and untimely antiviral treatment are possible high-risk factors for infections and death caused by the lowpathogenicity avian influenza A (H7N9). Person-to-person transmission of the H7N9 virus was not detected among close contacts, but such transmission should be investigated in the future. Expanding and enhancing surveillance will help in the early discovery and diagnosis of suspected cases, which will reduce the number of severe cases and deaths.

Surveillance of Avian H7N9 Virus in Various Environments of Zhejiang Province, China before and after Live Poultry Markets Were Closed in 2013-2014.

Background To date, there have been a total of 637 laboratory-confirmed cases of human infection with avian influenza A (H7N9) virus across mainland China, with 28% (179/637) of these reported in Zhejiang Province. Surveillance of avian H7N9 virus was conducted to investigate environmental contamination during H7N9 outbreaks. We sought to evaluate the prevalence of H7N9 in the environment, and the effects of poultry market closures on the incidence of human H7N9 cases. Methods We collected 6740 environmental samples from 751 sampling sites across 11 cities of Zhejiang Province (China) between January 2013 and March 2014. The presence of H7N9 was determined by reverse transcription polymerase chain reaction, with prevalence compared between sites and over time. The relationship between environmental contamination and human cases of H7N9 infection were analyzed using Spearman’s ranked correlation coefficient. Results Of the 6740 samples, 10.09% (680/6740) were H7N9-positive. The virus was found to circulate seasonally, and peaked during the spring and winter of 2013–2014. The prevalence of the virus decreased from the north to the southeast of the province, coinciding with the geographical distribution of human H7N9 cases. Compared with other sampling sites, live poultry markets (LPMs) had the highest prevalence of H7N9 virus at 13.94% (667/4784). Of the various sample types analyzed, virus prevalence was highest for chopping board swabs at 15.49% (110/710). The prevalence of the virus in the environment positively correlated with the incidence of human H7N9 cases (r2 = 0.498; P < 0.01). Cities with a higher incidence of human H7N9 cases also had a higher prevalence of H7N9 among samples and at sampling sites. Following the closure of LPMs at the end of January 2014, the prevalence of H7N9 decreased from 19.18% (487/2539) to 6.92% (79/1141). This corresponded with a decrease in the number of human H7N9 cases reported. Conclusions The prevalence of H7N9 virus in environmental samples oscillated seasonally, regardless of whether LPMs were open. The presence of H7N9 in environmental samples positively correlated with the number of human H7N9 cases, indicating that eradication of the virus from the environment is essential in reducing the numbers of H7N9 cases and halting the spread of the virus.

Seroprevalence of severe fever with thrombocytopenia syndrome virus in southeastern China and analysis of risk factors.

SUMMARY Severe fever with thrombocytopenia syndrome virus (SFTSV) has been prevalent for some time in China and it was first identified in 2010. However, the seroprevalence of SFTSV in the general population in southeastern China and risk factors associated with the infection are currently unclear. Blood samples were collected from seven counties across Zhejiang province and tested for the presence of SFTSV-specific IgG antibodies by ELISA. A total of 1380 blood samples were collected of which 5·51% were seropositive for SFTSV with seroprevalence varying significantly between sites. Seroprevalence of SFTSV in people who were family members of the patient, lived in the same village as the patient, or lived in a different village than the patient varied significantly. There was significant difference in seroprevalence between participants who bred domestic animals and participants who did not. Domestic animals are probably potential reservoir hosts and contact with domestic animals may be a transmission route of SFTSV.

Antibodies against severe fever with Thrombocytopenia syndrome Virus in healthy persons, China, 2013

In June 2013, a subclinical infection with severe fever with thrombocytopenia syndrome virus (SFTSV) was detected in Zhejiang Province, China, prompting seroprevalence studies in 6 districts within the province. Of 986 healthy persons tested, 71 had IgG antibodies against SFTSV. This finding suggests that most natural infections with SFTSV are mild or subclinical.

Comparison of Characteristics between Patients with H7N9 Living in Rural and Urban Areas of Zhejiang Province, China: A Preliminary Report

A total of 134 cases of H7N9 influenza infection were identified in 12 provinces of China between March 25 and September 31, 2013. Of these, 46 cases occurred in Zhejiang Province. We carried out a preliminary comparison of characteristics between rural and urban H7N9 cases from Zhejiang Province, China. Field investigations were conducted for each confirmed H7N9 case. A standardized questionnaire was used to collect information about demographics, exposure history, clinical signs and symptoms, timelines of medical visits and care after onset of illness. Of the 46 H7N9 cases in Zhejiang Province identified between March 25 and September 31, 2013, there were 16 rural cases and 30 urban cases. Compared to urban cases, there was a higher proportion of females among the rural cases [11/16 (69%) vs. 6/30 (20%), P = 0.001]. Among the rural cases, 14/15 (93%) with available data had a history of recent poultry exposure, which was significantly higher than that among urban cases (64%, P = 0.038). More patients from the rural group had a history of breeding poultry compared with those from the urban group [38% (6/16) vs. 10% (3/30), respectively; P = 0.025]. Interestingly, the median number of medical visits of patients from rural areas was higher than that of patients from urban areas (P = 0.046). There was no difference between the two groups in terms of age distribution, fatality rate, incubation period, symptoms, and underlying medical conditions. In conclusion, compared to patients from urban areas, more patients from rural areas were female, had an exposure history, had a history of breeding poultry, and had a higher number of medical visits. These findings indicate that there are different exposure patterns between patients living in rural and urban areas and that more rural cases were infected through backyard poultry breeding.

Nosocomial Co-Transmission of Avian Influenza A(H7N9) and A(H1N1)pdm09 Viruses between 2 Patients with Hematologic Disorders

Transmission of these viruses was limited to 2 immunocompromised patients in the same ward.