Epidemiological features and viral shedding in children with SARS-CoV-2 infection.

A pandemic of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection broke out all over the world; however, epidemiological data and viral shedding in pediatric patients are limited. We conducted a retrospective, multicenter study, and followed-up with all children from the families with SARS-CoV-2 infected members in Zhejiang Province, China. All infections were confirmed by testing the SARS-CoV-2 RNA with real-time reverse transcription PCR method, and epidemiological data between children and adults in the same families were compared. Effect of antiviral therapy was evaluated observationally and fecal-viral excretion times among groups with different antiviral regiments were compared with Kaplan-Meier plot. By 29 February 2020, 1298 cases from 883 families were confirmed with SARS-CoV-2 infection and 314 of which were families with children. Incidence of infection in child close contacts was significantly lower than that in adult contacts (13.2% vs 21.2%). The mean age of 43 pediatric cases was 8.2 years and mean incubation period was 9.1 days. Forty (93.0%) were family clustering. Thirty-three children had coronavirus disease 2019 (20 pneumonia) with mild symptoms and 10 were asymptomatic. Fecal SARS-CoV-2 RNA detection was positive in 91.4% (32/35) cases and some children had viral excretion time over 70 days. Viral clearance time was not different among the groups treated with different antiviral regiments. No subsequent infection was observed in family contacts of fecal-viral-excreting children. Children have lower susceptibility of SARS-CoV-2 infection, longer incubation, and fecal-viral excretion time. Positive results of fecal SARS-CoV-2 RNA detection were not used as indication for hospitalization or quarantine.

An adult gerbil model for evaluating potential coxsackievirus A16 vaccine candidates.

A suitable animal model of CVA16 infection is crucial in order to understand its pathogenesis and to help develop antiviral vaccines or screen therapeutic drugs. The neonatal mouse model has a short sensitivity period to CA16 infection, which is a major limitation. In this study, we demonstrate that adult (60-day-old) gerbils are susceptible to CVA16 infection at high doses (108.0 TCID50). A clinical isolate strain of CVA16 was inoculated intraperitoneally into adult gerbils, which subsequently developed significant clinical symptoms, including hind limb weakness, paralysis of one or both hind limbs, tremors, and eventual death from neurological disorders. Real-time RT-PCR revealed that viral loads in the spinal cord and brainstem were higher than those in other organs/tissues. Histopathological changes, such as neuronal degeneration, neuronal loss, and neuronophagia, were observed in the spinal cord, brainstem, and heart muscle, along with necrotizing myositis. Gerbils receiving both prime and boost immunizations of alum adjuvant inactivated vaccine exhibited no clinical signs of disease or mortality following challenge by CVA16, whereas 80% of control animals showed obvious clinical signs, including slowness, paralysis of one or both hind limbs, and eventual death, suggesting that the CVA16 vaccine can fully protect gerbils against CVA16 challenge. These results demonstrate that an adult gerbil model provides us with a useful tool for studying the pathogenesis and evaluating antiviral reagents of CVA16 infection. The development of this animal model would also be conducive to screening promising CVA16 vaccine candidates as well as further vaccination evaluation.

Genotypic and Epidemiological Trends of Acute Gastroenteritis Associated with Noroviruses in China from 2006 to 2016.

There are periodical norovirus-associated acute gastroenteritis outbreaks around the world. This study aimed to analyze the molecular and epidemiological features of norovirus infections in China during 2006-2016. We extracted epidemiological data from 132 norovirus outbreaks and the norovirus genotyping for 1291 sequences in China over the past ten years. A total of 132 norovirus outbreaks (8133 cases) were reported in China, where the east and south regions were most affected [47.7% (63/132)]. The highest number of outbreaks occurred in 2015. A seasonal pattern has been observed, with a peak from November to the following March. Most of the outbreaks occurred in middle and primary schools, accounting for 28.8% (38/132), and 28.0% (37/132) of outbreaks, respectively. The dominant age group was 10 to 19 years old, responsible for 75.7% (933/1232) of cases. Generally, the dominant genotypes was GII, for 81.9% (1058/1291) of sequences. G II.4 was the predominant genotype in China from 2004 to 2014. However, the GII.17 became more prevalent starting in 2014. Norovirus-associated acute gastroenteritis increased sharply in recent years caused by the emergence of GII.17, but epidemiological features have not changed during 2006-2016. Vigilant surveillance should be strengthened to promptly detect any variation.

Identifying Potential Norovirus Epidemics in China via Internet Surveillance.

BACKGROUND: Norovirus is a common virus that causes acute gastroenteritis worldwide, but a monitoring system for norovirus is unavailable in China. OBJECTIVE: We aimed to identify norovirus epidemics through Internet surveillance and construct an appropriate model to predict potential norovirus infections. METHODS: The norovirus-related data of a selected outbreak in Jiaxing Municipality, Zhejiang Province of China, in 2014 were collected from immediate epidemiological investigation, and the Internet search volume, as indicated by the Baidu Index, was acquired from the Baidu search engine. All correlated search keywords in relation to norovirus were captured, screened, and composited to establish the composite Baidu Index at different time lags by Spearman rank correlation. The optimal model was chosen and possibly predicted maps in Zhejiang Province were presented by ArcGIS software. RESULTS: The combination of two vital keywords at a time lag of 1 day was ultimately identified as optimal (ρ=.924, P<.001). The exponential curve model was constructed to fit the trend of this epidemic, suggesting that a one-unit increase in the mean composite Baidu Index contributed to an increase of norovirus infections by 2.15 times during the outbreak. In addition to Jiaxing Municipality, Hangzhou Municipality might have had some potential epidemics in the study time from the predicted model. CONCLUSIONS: Although there are limitations with early warning and unavoidable biases, Internet surveillance may be still useful for the monitoring of norovirus epidemics when a monitoring system is unavailable.

Coxsackievirus A16 induced neurological disorders in young gerbils which could serve as a new animal model for vaccine evaluation.

Coxsackievirus A16 (CA16) is one of the major pathogens associated with human hand, foot, and mouth disease (HFMD) in the Asia-pacific region. Although CA16 infections are generally mild, severe neurological manifestations or even death has been reported. Studies on CA16 pathogenesis and vaccine development are severely hampered because the small animal models that are currently available show major limitations. In this study, gerbils (Meriones unguiculatus) were investigated for their suitability as an animal model to study CA16 pathogenesis and vaccine development. Our results showed that gerbils up to the age of 21 days were fully susceptible to CA16 and all died within five days post-infection. CA16 showed a tropism towards the skeletal muscle, spinal cord and brainstem of gerbils, and severe lesions, including necrosis, were observed. In addition, an inactivated CA16 whole-virus vaccine administrated to gerbils was able to provide full protection to the gerbils against lethal doses of CA16 strains. These results demonstrate that gerbils are a suitable animal model to study CA16 infection and vaccine development.

Enterovirus 71 infection causes severe pulmonary lesions in gerbils, meriones unguiculatus, which can be prevented by passive immunization with specific antisera.

Neurogenic pulmonary edema caused by severe brainstem encephalitis is the leading cause of death in young children infected by Enterovirus 71 (EV71). However, no pulmonary lesions have been found in EV71-infected transgenic or non-transgenic mouse models. Development of a suitable animal model is important for studying EV71 pathogenesis and assessing effect of therapeutic approaches. We had found neurological disorders in EV71-induced young gerbils previously. Here, we report severe pulmonary lesions characterized with pulmonary congestion and hemorrhage in a gerbil model for EV71 infection. In the EV71-infected gerbils, six 21-day-old or younger gerbils presented with a sudden onset of symptoms and rapid illness progression after inoculation with 1×105.5 TCID50 of EV71 via intraperitoneal (IP) or intramuscular (IM) route. Respiratory symptoms were observed along with interstitial pneumonia, pulmonary congestion and extensive lung hemorrhage could be detected in the lung tissues by histopathological examination. EV71 viral titer was found to be peak at late stages of infection. EV71-induced pulmonary lesions, together with severe neurological disorders were also observed in gerbils, accurately mimicking the disease process in EV71-infected patients. Passive transfer with immune sera from EV71 infected adult gerbils with a neutralizing antibody (GMT=89) prevented severe pulmonary lesion formation after lethal EV71 challenge. These results establish this gerbil model as a useful platform for studying the pathogenesis of EV71-induced pulmonary lesions, immunotherapy and antiviral drugs.

[Retrospective analysis of clinical and epidemiological characteristics of hand-foot-and-mouth disease deceased cases in Zhejiang Province].

OBJECTIVE: To understand the clinical and epidemiological characteristics of hand-foot-and-mouth disease (HFMD) deceased cases. METHOD: Information of demographics, diagnosis and treatment, clinical symptoms and signs, laboratory test results, and epidemiological contact history of 72 HFMD cases who died between May 2008 and September 2011, in Zhejiang Province, were collected and analyzed. RESULT: The average age of the 72 cases was 1.8 years, 45 were males, accounting for 62.5%, 63 (87.5%) of the cases were scattered children. Eighteen counties reported 2 or more deaths, accounting for 46.1% (18/39) among the counties where the deaths were reported. The deaths occurred mainly in April to August, the peak occurred in May and June. Fever (98.4%, 63/64) and rash (95.1%, 58/61) were the most common symptoms, but the rash was not obvious at the first diagnosis. Fever occurred before the rash (79.0%, 49/62), persisted for 4 days in average. Vomiting (71.9%, 46/64), dyspnea (65.6%, 42/64), cyanosis (53.1%, 34/64) and impaired consciousness (51.6%, 33/64) were often seen among the cases; 53.1% (34/64) cases went to see the doctor on the first day, but 82.5%(52/63)cases were misdiagnosed. Time to diagnosis of HFMD was in average 3 days. About 3 to 4 days after the onset, the disease deteriorated sharply, deaths occurred within 1 day after admission in 78.9%(45/57)of the deceased cases; 85.0% (34/40) cases had high white blood cells level, mainly neutrophils increased, the ratio of neutrophil was more than 70% in 55.6% (15/27) of cases. Enterovirus 71 (EV71) infection was found in 93.3% (56/60) cases, the deceased cases often died of pulmonary hemorrhage (42.9%, 21/49) and encephalitis (34.7%, 17/49). The sanitary conditions of the cases' family were poor (65.5%, 36/55), but 73.3% (33/45) cases had no exposure history. CONCLUSION: The HFMD deceased cases were mostly younger aged boys, scattered children, nonlocal-residents, and had poor sanitation. They were often infected with EV71, had high fever but had no typical rash, no clear exposure history, they had increased leukocyte, and were often misdiagnosed. Three or 4 days after onset, the disease deteriorated abruptly, most cases died within 1 week after onset. To decrease the HFMD mortality, early detection of severe cases should be stressed, and relative measures should be taken. The guardian should be aware of having good sanitary situation and healthy habits.

[Etiological and molecular-epidemiological analysis on enterovirus associated encephalitis in Zhejiang, 2008-2012].

OBJECTIVE: In order to investigate etiology and molecular-epidemiological characteristics of enterovirus associated encephalitis (EAE) in Zhejiang, 2008-2012. Method Cerebrospinal fluid and stool specimens were collected from suspected EAE patients, who were admitted to our hospitals. RD and Hep-2 cell lines were used to isolate enterovirus (EV). Serotypes of these EV isolates were identified through neutralization test by using serotype specific anti-sera. VP1 genes of these isolates were sequenced, compared and used for the construction of phylogenetic tree. RESULTS: 127 (20.6%) human enterovirus (HEV) strains were isolated from 616 samples, which were collected from 610 patients. Serotypes of these EV isolates, including 60 coxsackievirus (CV), and 67 Echovirus (E)appeared to be CVA9, CVB1, CVB3-5, E3, E4, E6, E9, E14, E25 and E30, respectively. Predominant EV serotypes on EAE from 2008 to 2012 were seen as CVB3, CVB5, E6, E30 and E30, respectively. The full length of VP1 genes from different EV isolates was between 834 and 918 nucleotides. The VP1 gene similarities between these isolates and the reference strains were from 76.7% to 85.0% (nucleotides level) and 91.1% to 97.9% (amino acids level). The VP1 genes from E6 serotype isolates appeared most diverged, reaching 20.4% (nucleotides level) and 4.8% (amino acids level). Based on the generated phylogenetic tree, all the EV isolates were fallen on the same branch of HEV-B, and the isolates in the same serotype formed one sub-branch, suggesting there existed geographical and temporal effects. E6 isolates diverged into two branchlets. CONCLUSION: EVs from HEV-B were the etiologic agents for EAE in Zhejiang province from 2008 to 2012. All these EV isolates showed 12 serotypes, with predominant isolates varied every year. E30 was determined as the most dominant serotype while serotype E6 diverged into two sub-gene types.

[Study on the efficacy and safety of short-term treatment including fluoroquinolones anti-tuberculosis drugs for rifampicin resistant pulmonary tuberculosis].

OBJECTIVE: To evaluate the efficacy and safety of short-term treatment including fluoroquinolones anti-tuberculosis drugs for rifampicin resistant pulmonary tuberculosis (TB) in those areas carrying out the 'TB control project'. METHODS: TB cases involved in this study were from TB drug resistance surveillance in Heilongjiang province, Zhejiang province and Shenzhen city from 2004 to 2006. TB cases with rifampicin resistant were randomly divided into the treatment group (including fluoroquinolones anti-tuberculosis drugs group) and the control group (re-treatment regimen group). The treatment group was treated with 3RFT AM Ofx Pto PAS-INH/5RFT Ofx Pto PAS-INH while the control group was treated with 3 H3R3Z3E3S3/5 H3R3E3. Efficacy of short-term treatment was analyzed by per-protocol analysis (PP analysis) and intention-to-treat analysis (ITT analysis) while drug adverse reactions was also observed. RESULTS: (1) 154 patients with rifampicin resistant pulmonary tuberculosis were recruited among them, 25 (16.2%) were only resistant to rifampicin, 114 (74.0%) to MDR-TB and 15 (9.8%) to others (resistant R+S, resistant R+E and resistant R+E+S). 114 TB cases completed the full course of treatment,with 71 in the treatment group and 43 in the control group. (2) Sputum negative conversion rate of the treatment group and the control group were 78.9% and 65.1% (chi2CMH = 4.558, P = 0.011) respectively, by per-protocol analysis. Sputum negative conversion rate of the treatment group and the control group were 65.9% and 40.6% (chi2CMH = 0.272, P = 0.001) respectively, by intention-to-treat analysis. The sputum negative conversion rate of the treatment group was higher than in the control group when treating rifampicin resistant pulmonary tuberculosis and MDR-TB patients. (3) Three patients withdrew in each of the two groups because of adverse effects to the drugs. Rates of adverse reaction to drugs appeared to be 23.9% (17/71) and 18.6% (8/43) in the treatment and in the control groups, with no statistically significant difference between the two groups. CONCLUSION: The efficacy of treatment including fluoroquinolones anti-tuberculosis drugs group seemed better than the re-treatment regimen group in treating patients with rifampicin resistant pulmonary tuberculosis and those MDR-TB patients.

[Effects of two treatment regimens for drug-resistant tuberculosis in tuberculosis control project areas: a comparative study].

OBJECTIVES: To search for an ideal therapeutic regimen for multidrug resistant tuberculosis conforming to the situation of China. METHODS: One hundred and fifty-four patients with rifampin-resistant tuberculosis, 114 multi-drug resistant (MDR-TB) and 40 resistant to other drugs, in Heilongjiang, Zhejiang, and Shenzhen, 107 males and 47 females, aged 39 (19-77), were randomly divided into 2 groups: 85 patients in the group of drug-resistant regimen, 3RFT AM Ofx Pto PAS-INH/5RFT Ofx Pto PAS-INH regimen, including rifapentine (RFT), amikacin (Am), ofloxacin (Ofx), protionamide (Pto), para-aminosalicylic acid-isoniazid (PAS-INH) for 3 months and then RFT, Ofx, Pto, and PAS-INH for 5 months, and 69 in the retreatment regimen group undergoing 3 H3R3Z3E3S3/5 H3R3E3, including isoniazid (H), rifampin (R), pyrazinamide (Z), ethambutol (E), and streptomycin (S) for 3 months and then H, R, and E for 5 months. Sputum smear was checked and the sputum smear conversion rate was calculated as an effective treatment indicator 3, 6, and 8 months later. RESULTS: One hundred and fourteen of the 154 patients were treated for a good 8 months. The sputum smear conversion rate 8 months after treatment of the drug-resistant regimen group was 65.9% (56/85), significantly higher than that of the retreatment regimen group [40.6% (28/69), chi2 = 9.834, P = 0.002]. Eighty-five of the 114 MDR-TB patients had been treated for a good 8 months with a sputum smear conversion rate of 61.8% (42/68), significantly higher than that of the retreatment regimen group [39.1% (18/46), chi2 = 5.638, P = 0.018]. Sputum smear conversion at the end of the 8th month was related to age, course of disease, therapeutic regimen, and the type of drug-resistance (all P < 0.05). The side-effect rate of the drug-resistant regimen group was 23.9% (17/71), higher than that of the retreatment regimen group [18.6% (8/43)], but not significantly (chi2 = 0.446, P = 0.504). CONCLUSION: The drug-resistant regimen recommended above is more effective than the retreatment regimen and should be considered in the areas where the WHO guideline fails to be followed or drug sensitivity test (DST) cannot be conducted and adjusted according to the results of DST and treatment.