Zhenyu Gong

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.

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.

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.

Risk factors for human rabies in China.

In China, we have witnessed an increasing incidence of rabies in recent years and the number of deaths ranked first among the 39 notifiable infectious diseases. We conducted a case–control study to identify risk factors for human rabies infection and disease to recommend prevention and treatment among people exposed to rabies. Exposure site, pre‐exposure prophylaxis and post‐exposure prophylaxis were significantly associated with rabies infection. Exposure site at upper limb and trunk or at lower limb were at lower risk as compared with head‐exposed patients. The OR was 0.09(95% CI: 0.009–0.93) and 0.01(95% CI: 0.001–0.115) respectively. Pre‐exposure prophylaxis (OR = 0.05, 95% CI: 0.03–0.11) and post‐exposure prophylaxis (OR = 0.02, 95% CI: 0.01–0.40) were both protective factors as compared with no prophylaxis. For patients who had post‐exposure prophylaxis, dose for the first injection and immunity procedure were significantly associated with rabies infection.

Factors associated with Severe Fever with Thrombocytopenia Syndrome infection and fatal outcome.

Severe fever with thrombocytopenia syndrome (SFTS) is emerging in China and the incidence increased year by year. In this study, we conducted case control study to explore factors associated with SFTS virus (SFTSV) infection and fatal outcome. In the study of factors associated with SFTSV infection, a total of 216 individuals participated the study, including 72 cases and 144 matched controls. There were significant differences in proportion of history of tick bite and breeding domestic animals between cases and controls. Of note, individuals who were unclear whether they had been bitten by ticks had the highest risk of SFTSV infection and odds ratio (OR) was 10.222. In the study of factors associated with SFTS fatal outcome, a total of 129 cases participated the study including 16 deaths and 113 survivors. Significant differences were observed in body mass index (BMI), intervals from illness onset to confirmation, and proportion of gingival hemorrhage between deaths and survivors, whose ORs of these factors were 3.903, 1.996, and 3.826, respectively. Our results suggest that all patients with fever, thrombocytopenia and leukocytopenia in SFTS endemic areas should be suspected of SFTS, even they don’t have history of tick bite, and more intense treatment should be administered to patients with abnormal BMI before laboratory parameters are detected.

Mild Illness in Avian Influenza A(H7N9) Virus–Infected Poultry Worker, Huzhou, China, April 2013

During April 2013 in China, mild respiratory symptoms developed in 1/61 workers who had culled influenza A(H7N9) virus–infected poultry. Laboratory testing confirmed A(H7N9) infection in the worker and showed that the virus persisted longer in sputum than pharyngeal swab samples. Pharyngeal swab samples from the other workers were negative for A(H7N9) virus.

Hypothesis On The Source, Transmission and Characteristics of Infection of Avian Influenza A (H7N9) Virus – Based On Analysis of Field Epidemiological Investigation and Gene Sequence Analysis

On 31 March 2013, the National Health and Family Planning Commission announced that human infections with influenza A (H7N9) virus had occurred in Shanghai and Anhui provinces, China. H7N9 cases were later detected in Jiangsu and Zhejiang provinces. It was estimated that the virus first spread northward along the route taken by migratory birds and then spread to neighbouring provinces with the sale of poultry. Epidemiological studies were carried out on samples from the external environment of infected cases, transmission routes, farmers markets and live poultry markets. Phylogenetic study of viral sequences from human and avian infections in Zhejiang showed that those from Shanghai and Jiangsu provinces along Taihu Lake were highly homologous with those from the external environment. This suggests that avian viruses carried by waterfowl combined with the virus carried by migratory birds, giving rise to avian influenza virus H7N9, which is highly pathogenic to humans. It is possible that the virus was transmitted by local wildfowl to domestic poultry and then to humans, or spread further by means of trading in wholesale poultry markets. As the weather has turned warm, and with measures adopted to terminate poultry trade and facilitate health communication, the epidemic in the first half of the year has been kept under control. However, the infection source in the triangular area around Taihu Lake still remains. The H7N9 epidemic will probably hit the area later in the year and next spring when the migratory birds return and may even spread to other areas. Great importance should therefore be attached to the wildfowl in Taihu Lake as the repository and disseminator of the virus: investigation and study of this population is essential.

Genetic Susceptibility Is One of the Determinants for Severe Fever with Thrombocytopenia Syndrome Virus Infection and Fatal Outcome: An Epidemiological Investigation.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease in China and case-fatality rate of SFTS is very high (approximately 10%). However, genetic susceptibility for SFTS virus (SFTSV) infection and fatal outcome of SFTSV infection in humans are unclear. In this study, we investigated the clinical, laboratory and epidemiological features of SFTS in a cluster of three sisters who died of SFTSV infection between late April and mid-May 2014. Before disease onset, two of the sisters (Case A and case B) had common exposure history for ticks by working together in a field to pick tea leaves from April 8 to April 12. The third sister (Case C) did not live or work together with case A and B, but had ticks in her living environment. SFTSV RNA sequences were amplified from three cases were not identical, suggesting that the three sisters were most likely infected with SFTSV through tick bite rather than through person-to-person transmission of SFTSV. The sequence of SFTSV from case C was identical to SFTSV sequences from 3 groups of ticks collected around the residential area of case C. Seroprevalence of SFTSV IgG antibody among healthy population in the area where the patients resided was 4.05% (3/74). The majority of SFTSV infections were mild cases and all three sisters died of SFTSV infection suggested that they were highly susceptible to SFTSV. Our findings indicated that genetic susceptibility was a risk factor for SFTSV infection and fatal outcome.

Human rabies in Zhejiang Province, China.

OBJECTIVES To explore the epidemiological characteristics of human rabies in Zhejiang Province, China. METHODS Descriptive and statistical analyses were performed using data collected through interview with human rabies cases or their relatives during 2007 to 2014. A standardized questionnaire was used to collect the data. RESULTS Two hundred and one cases of human rabies were diagnosed in Zhejiang Province between 2007 and 2014, with a gradually declining annual incidence. Of the rabies cases identified, 61.2% were aged 40-65 years, and the male to female ratio was 2.30:1; 63.7% of cases occurred in the summer and autumn. The two most reported occupations were farmer (69.2%) and rural laborer (15.4%). Wenzhou, Jinhua, and Huzhou were the three cities with the most reported cases. The majority of cases (92.8%) were attributed to canines, and 71.0% of animal vectors were household animals. Less than half of the cases (41.4%) sought wound treatment after exposure. Post-exposure passive immunization was given to 9.7% and active immunization to 2.3%. Cases with a wound on the head/face only had a significantly shorter incubation than those with wounds at other sites (p<0.05); cases with a wound on the hand only had a significantly shorter incubation than those with a wound on the lower limb below the knee only (p<0.001). Non-resident cases were significantly younger (p<0.001) and had a shorter disease duration (p=0.015) than locally resident cases. CONCLUSIONS The majority of rabies cases occurred among 40-65-year-old male residents of northern, mid-west, and southeast Zhejiang Province. Further health education is needed to increase the coverage of post-exposure prophylaxis (PEP) in people exposed to possible rabid animals and rabies vaccine use in household animals.

Zagreb Regimen, an Abbreviated Intramuscular Schedule for Rabies Vaccination

ABSTRACT The Zagreb regimen, an abbreviated intramuscular schedule for rabies vaccination, was developed by I. Vodopija and colleagues of the Zagreb Institute of Public Health in Croatia in the 1980s. It was recommended by WHO as one of the intramuscular (IM) schedules for rabies vaccination in 2010. We reviewed the literature on the immunogenicity, safety, economic burden, and compliance of the Zagreb 2-1-1 regimen. Compared to Essen, another IM schedule recommended by WHO, Zagreb has higher compliance, lower medical cost, and better immunogenicity at an early stage.