Establishment and application of a rapid assay for GII.4/GII.17 NoV detection based on the combination of CRISPR/Cas13a and isothermal amplification

Introduction

Norovirus (NoV) is one of the most important agents responsible for viral acute gastroenteritis, among which GII.4 NoV is the predominant strain worldwide, and GII.17 NoV surpassed GII.4 in some epidemic seasons. Rapid and accurate gene recognition is essential for a timely response to NoV outbreaks.

Methods

In the present study, the highly conserved regions of GII.4 and GII.17 NoVs were identified in the junction of open reading frame (ORF) 1 and ORF2 and then amplified by isothermal recombinase-aided amplification (RAA), followed by the cleavage of CRISPR-Cas13a with screened CRISPR RNAs (crRNAs) and RAA primers. The entire detection procedure could be completed within 40 min using a thermostat, and the results could be read out by the naked eye under a portable blue light transilluminator.

Discussion

The assay showed a high sensitivity of 97.96% and a high specificity of 100.0%. It offered a low limit of detection (LOD) of 2.5×100 copies/reaction and a coincidence rate of 96.75% in 71 clinical fecal samples. Overall, rapid and inexpensive detection of GII.4/GII.17 NoVs was established, which makes it possible to be used in areas with limited resources, particularly in low-income countries. Furthermore, it will contribute to assessing transmission risks and implementing control measures for GII.4/GII.17 NoVs, making healthcare more accessible worldwide.

Serological surveillance of GI norovirus reveals persistence of blockade antibody in a Jidong community-based prospective cohort, 2014-2018

Introduction

Herd immunity against norovirus (NoV) is poorly understood in terms of its serological properties and vaccine designs. The precise neutralizing serological features of genotype I (GI) NoV have not been studied.

Methods

To expand insights on vaccine design and herd immunity of NoVs, seroprevalence and seroincidence of NoV genotypes GI.2, GI.3, and GI.9 were determined using blockade antibodies based on a 5-year longitudinal serosurveillance among 449 residents in Jidong community.

Results

Correlation between human histo-blood group antigens (HBGAs) and GI NoV, and dynamic and persistency of antibodies were also analyzed. Seroprevalence of GI.2, GI.3, and GI.9 NoV were 15.1%-18.0%, 35.0%-38.8%, and 17.6%-22.0%; seroincidences were 10.0, 21.0, and 11.0 per 100.0 person-year from 2014 to 2018, respectively. Blockade antibodies positive to GI.2 and GI.3 NoV were significantly associated with HBGA phenotypes, including blood types A, B (excluding GI.3), and O+; Lewis phenotypes Leb+/Ley+ and Lea+b+/Lex+y+; and secretors. The overall decay rate of anti-GI.2 antibody was -5.9%/year (95% CI: -7.1% to -4.8%/year), which was significantly faster than that of GI.3 [-3.6%/year (95% CI: -4.6% to -2.6%/year)] and GI.9 strains [-4.0%/year (95% CI: -4.7% to -3.3%/year)]. The duration of anti-GI.2, GI.3, and GI.9 NoV antibodies estimated by generalized linear model (GLM) was approximately 2.3, 4.2, and 4.8 years, respectively.

Discussion

In conclusion, enhanced community surveillance of GI NoV is needed, and even one-shot vaccine may provide coast-efficient health benefits against GI NoV infection.

Development and evaluation of a new luciferase immunosorbent assay to detect GII.6 norovirus-specific IgG in different domestic and wild animals

Noroviruses (NoVs) are the leading viral pathogens globally causing acute gastroenteritis (AGE) in humans, posing a significant global health threat and economic burden. Recent investigations revealed that human NoVs had been detected in different animals, which raises concerns about whether NoVs are potential zoonotic diseases. This study developed a novel luciferase immunosorbent assay (LISA) to detect GII.6 NoV IgG based on P protein of VP1. The LISA showed high specificity (99.20%) and sensitivity (92.00%) with 4-16 times more sensitivity compared with an ELISA. NoV-LISA was reproducible with human serum regarding the inter- and intra-assay coefficient of variance values. Potential cross-reactivity was also evaluated using mice serum immunized by other antigens, which showed that NoV-LISA could differentiate GII.6 NoV from rotavirus and various genotypes of NoV. Specific GII.6 NoV IgG was widely detected in different domestic and wild animals, including dogs, pigs, bats, rats, and home shrews, with various IgG-positive rates ranging from 2.5 to 74.4%. In conclusion, our newly developed NoV-LISA assay is suitable for NoV-specific IgG detection in humans and animals. The wide distribution of IgG antibodies against human NoV indicates potential zoonotic transmission between humans and animals.

Under-Five Mortality in Sierra Leone and Possible Associated Factors: Evidence from the 2019 Demographic and Health Survey

High under-five mortality rate remains one of the public health challenges, especially in sub-Saharans Africa, accounting for more than half of all global cases. Sierra Leone was and still one of the countries with the highest under-five mortality rate. Using the latest 2019 SLDHS data, we investigated factors associated with under-five mortality in Sierra Leone. A total of 9771 mothers aged 15-49 years in the country were interviewed and included in the analysis. The dependent variable is child status (dead=1; alive=0). A total of 871 (9%) children died before their fifth birthday. Maternal age of 20-24 years (AOR=0.46; CI=0.33-0.64; P<0.001) up to 40-44 years (AOR=0.43; CI=0.27-0.7; P=0.001), currently breastfeeding (AOR=0.20; CI=0.17-0.24; P<0.001), maternal media exposure and usage of reading newspapers/magazines less than once a week (AOR=0.48; CI=0.28-0.85; P=0.011) were more likely to enhance child survivability through their fifth birthday. Also, the child sex being female (AOR=0.68; CI=0.59-0.79) was more likely to survive under-five mortality compared to their male counterpart. On the other hand, mothers who listened to radio at least once a week (AOR=1.31; CI=1.08-1.59; P=0.007) watched television less than once a week (AOR=1.48; CI=1.16-1.90), had two (AOR=3.4, CI=2.78-4.16; P<0.001) or three and above birth (AOR=8.11; CI=6.07-10.83; P<0.001) in five years, had multiple birth children (AOR=1.41; CI=1.08-1.86) and very small-sized child at birth (AOR= 1.95; CI=1.41-2.70) were more likely to lose their children below the age of five years. The factors contributing to under-five mortality in Sierra Leone are critical to ensuring child survival and improving maternal health. Breastfeeding, maternal age, media exposure, child's sex, multiple birth type, very small-sized child and the total number of births in five years were significant drivers of under-five mortality. The result affirms the need for attention to be focused on enhancing the survival rate of under-five children in Sierra Leone.

Serological surveillance of noroviruses in a community-based prospective cohort: a study protocol

INTRODUCTION

Noroviruses are the leading cause of viral acute gastroenteritis affecting all age groups. Since 2014, the previous rarely reported GII.P17-GII.17 and recombinant GII.P16-GII.2 norovirus emerged, replacing GII.4 predominant genotype, causing increased outbreaks in China and other countries. Meanwhile, GII.4/2012 Sydney strain has re-emerged as the dominant variant in many places in 2015-2018. The role of herd immunity as the driving force during these new emerging or re-emerging noroviruses is poorly defined. Serological surveillance studies on community-based prospective cohort on norovirus are highly needed.

METHODS AND ANALYSES

This study will include 1000 out of 9798 participants aged 18 years and above from Caofeidian district, Tangshan city, northern China. Baseline data on sociodemographic characteristics and blood samples were collected in 2013-2014. Blood collection will be replicated annually throughout the cohort until 2023. Saliva samples were also collected in 2016. The seroprevalence and seroincidence of blockade antibodies against norovirus genotypes of GII.P17-GII.17, GII.P16-GII.2, the re-emerged GII.4/2012 and potential novel pandemic variants will be evaluated by ELISA. Associations between genotype blockade antibodies and sociodemographic factors and human histo-blood group antigens will be evaluated using univariate and multivariate analysis. The dynamics of herd immunity duration will be estimated in this longitudinal surveillance.

ETHICS AND DISSEMINATION

The study has been approved by the Ethical Committees of the Staff Hospital of Jidong oil-field of China National Petroleum Corporation. This study will provide insight into the seroprevalence and seroincidence of noroviruses, and their relationships with sociodemographic characteristics and genetic susceptibility. It will also explain herd immunity of the emerged and re-emerged genotypes or variants. The study will further enable an understanding of the mechanism driving the replacement of norovirus genotypes. Research findings will be disseminated in peer-reviewed journals and at scientific meetings.

Characterization of Antigenic Relatedness Among GI Norovirus Genotypes Using Serum Samples From Norovirus-Infected Patients and Mouse Sera

Characterizing diversity and the antigenic relatedness of norovirus remains a primary focus in understanding its biological properties and vaccine designs. The precise antigenic and serological features of GI genotypes have not been studied. The study represented an investigation on a gastroenteritis outbreak related to GI.3 norovirus and the three most detected GI genotypes, GI.2 (belonging to immunotype B), GI.3 and GI.9 (belonging to immunotype C), were selected to characterize their phylogenetic relationship, HBGA binding profiles and antigenic relatedness within (intra-immunotype), and between (inter-immunotypes) genotypes using mouse sera and patient’s serum samples from the GI.3 related outbreak. Wide HBGA binding profiles and evolution of binding affinity were observed in the three GI genotypes studied. A low specific blockade antibody to GI.3 in the population generated the pool of susceptible individuals and supported virus spread in the outbreak. We found strong blockade immune response in homologous strains, moderate intra-immunotype blockade but weak inter-immunotypes blockade in humans following GI.3 norovirus infections. These findings further support the immunotypes grouping and will be valuable for optimizing the design of norovirus vaccine.

[Development of a quantitative serum assay of Golgi protein 73 in hepatocellular carcinoma using xMAP technology]

Objective: To establish a quantitative assay of serum Golgi protein 73 (GP73) using xMAP technology and evaluate its performance. Methods: Monoclonal antibodies against GP73 were prepared and purified, and antibody pair screening was performed by double-antibody sandwich enzyme-linked immunosorbent assay. The screened antibodies were used to construct a Luminex liquid chip detection system, and the analysis performance of the detection system was evaluated. The serum levels of GP73 were detected in 90 clinical samples from healthy controls and patients with chronic hepatitis B infection (CHB) and hepatocellular carcinoma (HCC). Results: Five anti-GP73 monoclonal antibodies were prepared and purified, and 5 antibody pairs were successfully screened. The Luminex liquid chip detection system of GP73 was successfully constructed using 8F10D1 and 10B9F11 antibody pairs. The analytical performance evaluation showed that the sensitivity of this system was 0.25 ng/ml and the dynamic range was 0.25-100 ng/ml. No cross reactivity was observed. The intra- and inter-assay variation for GP73 was <8% and <11%, respectively. The recovery was 83%-92%. The linear regression equation was y=1.141x+ 6.436 (r(2)=0.998 4, P<0.001). The GP73 concentrations in the serum samples of healthy control, CHB group, and HCC group were 42.8 (38.68, 55.90) ng/ml, 61.49 (43.59, 81) ng/ml, and 122.78 (49.36 liter, 264.55) ng/ml, respectively. The levels of GP73 in HCC group were significantly higher than those in CHB group and healthy controls (P<0.05). Moreover, the levels of GP73 in CHB group were significantly higher than those in healthy controls (P<0.05). Conclusions: A liquid chip detection system of GP73 was successfully constructed. It provides a powerful tool for the clinical application of GP73 in the future.

[Blocking effects of serum antibodies against HBGA binding to norovirus GII.4 of population in oyster culture area of Guangdong Province]

Objective: Evaluate GII.4 norovirus infection and blocking effects of serum antibodies against HBGAs binding to GII.4 norovirus of population in oyster culture area, provide references for screening of fully human monoclonal antibody. Methods: Using a random survey method to collect blood and saliva samples in oyster culture area, select serum samples from the inland region of Guangdong as control group. Identification of salivary HBGA receptor phenotype and detection of serum antibody levels between two areas by ELISA. A vitro neutralization model was to determine the efficiency of serum antibodies blocking GII.4 norovirus and HBGA receptors binding. Results: The age were (50.68 ± 15.17), (52.52 ± 15.90) and (51.37 ± 13.32) years old of 2015, 2016 in experimental group, and in control group, respectively. Males accounted for 5.9% (70/195), 36.6%(60/164), 40.8% (69/169) (χ(2)=0.93, P=0.334). The mean value of serum antibodies Absorbance value was 2.521±0.05 of 2015 and was 2.583±0.045 of 2016 in oyster culture area, the mean value was 2.249±0.05 in control group, there was a statistical difference among three group (F=13.28, P<0.001). The antibody prevalence in the three groups was 100%. BT50 geometric mean titer (GMT) of oyster culture area in 2015 was 423.1±40.11, culture group was 248.2±25.63, there was a statistical difference (t=3.73, P<0.001). Conclusion: The population in oyster culture area does have more chance of exposure and infection GII.4 norovirus, Serum antibody of blocking ability in oyster culture areas is better than the general population in inland city. Suggesting that the population is more immunity resistant infected GII.4 norovirus.

Characterization of Antigenic Relatedness between GII.4 and GII.17 Noroviruses by Use of Serum Samples from Norovirus-Infected Patients

A novel GII.17 norovirus variant caused major gastroenteritis epidemics in China in 2014 to 2016. To explore the host immune factors in selection of the emergence of this new variant, we characterized its antigenic relatedness with the GII.4 noroviruses that have dominated in China for decades. Through an enzyme-linked immunosorbent assay (ELISA) and a histo-blood group antigen (HBGA) blocking assay using sera from GII.4 and the GII.17 variant-infected patients, respectively, we observed limited cross-immune reactivity by the ELISA but little reactivity by the HBGA blocking assay between GII.4 norovirus and the new GII.17 variant. Our data suggest that, among other possible factors, GII.4-specific herd immunity had little role in the emergence of the new GII.17 variant. Thus, GII.17 may be an important active antigenic type or immunotype that needs to be considered for future vaccine strategies against human noroviruses.

Antigenic Relatedness of Norovirus GII.4 Variants Determined by Human Challenge Sera

The GII.4 noroviruses (NoVs) are a single genotype that is responsible for over 50% of NoV gastroenteritis epidemics worldwide. However, GII.4 NoVs have been found to undergo antigenic drifts, likely selected by host herd immunity, which raises an issue for vaccine strategies against NoVs. We previously characterized GII.4 NoV antigenic variations and found significant levels of antigenic relatedness among different GII.4 variants. Further characterization of the genetic and antigenic relatedness of recent GII.4 variants (2008b and 2010 cluster) was performed in this study. The amino acid sequences of the receptor binding interfaces were highly conserved among all GII.4 variants from the past two decades. Using serum samples from patients enrolled in a GII.4 virus challenge study, significant cross-reactivity between major GII.4 variants from 1998 to 2012 was observed using enzyme-linked immunosorbent assays and HBGA receptor blocking assays. The overall abilities of GII.4 NoVs to bind to the A/B/H HBGAs were maintained while their binding affinities to individual ABH antigens varied. These results highlight the importance of human HBGAs in NoV evolution and how conserved antigenic types impact vaccine development against GII.4 variants.

A dual chicken IgY against rotavirus and norovirus

Rotavirus (RV) and norovirus (NoV) are the two most important causes of viral gastroenteritis. While vaccine remains an effective prophylactic strategy, development of other approaches, such as passive immunization to control and treat clinical infection and illness of these two pathogens, is necessary. Previously we demonstrated that high titers of NoV-specific IgY were readily developed by immunization of chickens with the NoV P particles. In this study, we developed a dual IgY against both RV and NoV through immunization of chickens with a divalent vaccine comprising neutralizing antigens of both RV and NoV. This divalent vaccine, named P-VP8(∗) particle, is made of the NoV P particle as a carrier with the RV spike protein VP8(∗) as a surface insertion. Approximately 45mg of IgY were readily obtained from each yolk with high titers of anti-P particle and anti-VP8(∗) antibodies detected by ELISA, Western blot, HBGA blocking (NoV and RV) and neutralization (RV) assays. Reductions of RV replication were observed with viruses treated with the IgY before and after inoculation into cells, suggesting an application of the IgY as both prophylactic and therapeutic treatment. Collectively, our data suggested that the P-VP8(∗) based IgY could serve as a practical approach against both NoV and RV.

Evaluation of anti-norovirus IgY from egg yolk of chickens immunized with norovirus P particles

Noroviruses (NoVs) are a leading cause of epidemic acute gastroenteritis affecting millions of people worldwide. Understanding of NoV remains limited due to the lack of a cell culture system and small animal models. Currently, there are no effective vaccines or antivirals against NoVs. In this study, an approach for large-scale production of anti-NoV antibodies for use as a potential treatment for NoV disease using passive immunization was evaluated. NoV-specific immunoglobulins (IgYs) were produced by immunizing chickens with NoV P particles. The birds continuously produced high titers of antibodies in their eggs for at least 3months, in which NoV-specific antibody levels reached 4.7-9.2mg/egg yolk. The egg yolk antibodies strongly reacted with NoV P particles by both ELISA and Western blot and blocked NoV virus-like particle (VLP) and P particle binding to the histo-blood group antigen (HBGA) receptors with a BT(50) of about 1:800. The blocking activity of the chicken IgY remained after an incubation at 70°C for 30min or treatments at pH 4-9 for 3h. These data suggested that chicken IgY could be a practical strategy for large-scale production of anti-NoV antibodies for potential use as passive immunization against NoV infection, as well as for diagnostic purposes.

Tannic acid inhibited norovirus binding to HBGA receptors, a study of 50 Chinese medicinal herbs

Noroviruses (NoVs) are the leading cause of viral acute gastroenteritis affecting people of all ages worldwide. The disease is difficult to control due to its widespread nature and lack of an antiviral or vaccine. NoV infection relies on the interaction of the viruses with histo-blood group antigens (HBGAs) as host receptors. Here we investigated inhibition effects of Chinese medicinal herbs against NoVs binding to HBGAs for potential antivirals against NoVs. Blocking assays was performed using the NoV protrusion (P) protein as NoV surrogate and saliva as HBGAs. Among 50 clinically effective Chinese medicinal herbs against gastroenteritis diseases, two herbs were found highly effective. Chinese Gall blocked NoV P dimer binding to type A saliva at IC(50)=5.35 μg/ml and to B saliva at IC(50)=21.7 μg/ml. Similarly, Pomegranate blocked binding of NoV P dimer to type A saliva at IC(50)=15.59 μg/ml and B saliva at IC(50)=66.67 μg/ml. Literature data on preliminary biochemistry analysis showed that tannic acid is a common composition in the extracts of the two herbs, so we speculate that it might be the effective compound and further studies using commercially available, highly purified tannic acid confirmed the tannic acid as a strong inhibitor in the binding of NoV P protein to both A and B saliva (IC(50)≈0.1 μM). In addition, we tested different forms of hydrolysable tannins with different alkyl esters, including gallic acid, ethyl gallate, lauryl gallate, octyl gallate and propyl gallate. However, none of these tannins-derivatives revealed detectable inhibiting activities. Our data suggested that tannic acid is a promising candidate antiviral against NoVs.

Development and validation of a HPLC-MS/MS method for the determination of venlafaxine enantiomers and application to a pharmacokinetic study in healthy Chinese volunteers

An HPLC-MS/MS method has been developed and validated for the determination of venlafaxine enantiomers in human plasma and applied to a pharmacokinetic study in healthy Chinese volunteers. The method was carried out on a vancomycin chiral column (5 µm, 250 × 4.6 mm) maintained at 25°C. The mobile phase was methanol-water containing 30 mmol/L ammonium acetate, pH 3.3 adjusted with aqueous ammonia (8:92, v/v) at the flow rate 1.0 mL/min. A tandem mass spectrometer with an electrospray interface was operated in the multiple reaction monitoring mode to detect the selected ions pair at m/z 278.0 → 120.8 for venlafaxine enantiomers and m/z 294.8 → 266.7 for estazolanm (internal standard). The method was linear in the concentration range of 0.28-423.0 ng/mL. The lower limit of quantification was 0.28 ng/mL. The intra-and inter-day relative standard deviations were less than 9.7%. The method was successfully applied for the evaluation of pharmacokinetic profiles of venlafaxine enantiomers in 18 healthy volunteers. Validation parameters such as the specificity, linearity, precision, accuracy and stability were evaluated, giving results within the acceptable range. Pharmacokinetic parameters of the venlafaxine enantiomers were measured in the 18 healthy Chinese volunteers who received a single regimen with venlafaxine hydrochloride capsules. The results show that AUC((0-∞)) , C(max) and t(1/2) between S-venlafaxine and R-venlafaxine are significantly different (p < 0.05).

Surveillance and risk factors of norovirus gastroenteritis among children in a southern city of China in the fall-winter seasons of 2003-2006

AIM

Noroviruses (NoVs) are an important cause of acute gastroenteritis but knowledge on the disease burden and epidemiology in children in the developing countries remains limited. In this study, we performed a surveillance of NoV gastroenteritis in children of China to address some of the questions.

METHODS

Faecal specimens from children (<5 years of age) at outpatient clinics of the Nan Fang Hospital in Guangzhou, China during the fall-winter seasons in 2003-2006 were tested for rotaviruses (RVs) and NoVs. A questionnaire on clinical records and hygiene habits was collected from each patient.

RESULTS

Among 957 stool specimens tested, 488 (51%) specimens were positive for RVs. NoVs were detected in 112 (24%) of the 469 RV negative specimens. The Genogroup II (GII), particularly GII-4, viruses were predominant. No significant difference of clinical symptoms, hospitalisation and patient care expenses were found between children infected with NoVs and RVs. Consumption of uncooked food is a risk for NoV infection. Contact with diarrhoea patients is a suspected risk factor. Cutting nails frequently is a protective factor against NoV infection.

CONCLUSIONS

NoVs are an important cause of acute gastroenteritis in children which need special attention of patient care at the clinics in addition to RVs. The awareness of those risk factors may help future disease control and prevention.

First Report of Sapwood Rot of Peach Caused by Schizophyllum commune in China

Peach,Prunus persica (L.) Batsch, is widely cultivated in gardens and plantations in northern China. During the summer of 2002, a severe sapwood rot of 5-year-old saplings was observed in a commercial nursery near Tieling, Liaoning Province, northeast China, 42°24'N, 123°55'E. More than 80% of saplings were infected and 35% were dead. Leaves were chlorotic or necrotic and dry, and wood discoloration and white sapwood rot were observed in cross sections of infected trees. Basidiocarps on the diseased trees were identified as Schizophyllum commune Fr.:Fr. (2); on potato dextrose agar (PDA), isolates obtained from decayed wood yielded colonies characteristic of S. commune as well (3). Basidiocarps had been initiated in early June and sometimes fruited over the entire length of the stem and some parts of major branches. Liaoning Province had an abnormally cold winter in 2001 and freeze injury may have predisposed the saplings to S. commune. In addition to P. persica, P. pseudocerasus Lindl. and P. salicina Lindl. were symptomatic. Pathogenicity was confirmed by inoculation of healthy saplings of peach in the greenhouse. Saplings were subjected to freezing for 1 week and 15 were inoculated with S. commune and five were inoculated with agar. Mycelial plugs, grown for 9 days on PDA, were the inoculum for stem wounds. The inoculated area was then covered by wet cotton and wrapped in Parafilm for 2 weeks. Symptoms developed on 14 of 15 inoculated saplings after 6 weeks. Symptoms progressed from chlorotic leaves to decayed bark and wood. After 10 weeks, 11 saplings were dead. The pathogen was reisolated from 13 of 14 symptomatic saplings, and fruiting bodies of S. commune developed on eight saplings. Control saplings remained symptomless. In China and the United States, S. commune is widely reported as a saprotroph or opportunistic pathogen of many woody angiosperms (4) and some gymnosperms (1). To our knowledge, this is the first report of S. commune causing sapwood rot of P. persica in China. References: (1) D. F. Farr et al. Fungal Databases, Systematic Botany and Mycology Laboratory. On-line publication. ARS, USDA, 2005. (2) J. P. Lindsey et al. Bibl. Mycol. 63:1, 1978. (3) M. K. Nobles. Can. J. Res. Sect. C Bot. Sci. 26:281, 1948. (4) F. L. Tai. Sylloge Fungorum Sinicorum. Science Press, Beijing, 1979.

First Report of Laminated Root Rot on Sabina przewalskii Caused by Phellinus weirii sensu stricto in China

Members of the Phellinus weirii complex cause laminated root rot of living conifers. The cedar type (P. weirii (Murrill) Gilb. sensu stricto) of the complex is usually found on species of the Cupressaceae family, especially Thuja plicata in western North America, and the Douglas-fir type (P. sulphurascens Pilát) is found on species of the Pinaceae family (1,2,3). Outside North America, P. weirii occurs on species of Juniperus in the Ural Mountains, and P. sulphurascens occurs on other conifers in eastern Asia, including China (1). During a field inventory of wood-decay fungi in western China in 2003, laminated root rot of Sabina przewalskii (synonym Juniperus przewalskii) was found in natural forests of the Qilian Mountains in Qinghai Province (37°36'N and 102°15'E). Trees were approximately 80 to 150 years old and occurred in pure stands. Distinct disease patches that were as much as one hectare consisted of dead-standing and symptomatic trees, suggesting that the fungus spread by root contact. Symptomatic trees showed slow growth, thin crowns, and chlorotic foliage. After cutting several of the symptomatic trees, cambial necrosis and wood decay were found, and the trees apparently died when the cambial necrosis girdled the base of the trees. The wood of infected trees was reddish brown at the early stages of decay and later had numerous small cavities and separated into sheets at the junction of annual rings. Perennial, poroid, resupinate, dark brown basidiocarps formed on the root surface of dead trees. The basidiocarps had a monomitic hyphal system, hyphae without clamp connections, trama tissue with hyphoid setae, and thin-walled, hyaline, smooth, ellipsoid basidiospores. The fungus was identified as P. weirii and distinguished from P. sulphurascens by its perennial basidiocarps, smaller pores (5 to 8 versus 4 to 5 per mm), and narrower hyphoid setae (4 to 6 versus 5 to 10 μm in diameter). P. weirii also resembles P. ferrugineofuscus (P. Karst.) Bourdot in macro-morphology, but the latter species is a saprophyte and has allantoid to almost lunate basidiospores. The studied specimens of P. weirii and P. sulphurascens are preserved at the herbaria of the Botanical Museum of the University of Helsinki, the Institute of Applied Ecology, and the Chinese Academy of Sciences as DAOM 8734, Lowe 6960, TAA 52744, 55644, and 103812, and Dai 988, 2053, 2061, 2527, and 5067. To my knowledge, this is the first report of P. weirii sensu stricto from China and the first report of laminated root rot on S. przewalskii. References: (1) Y. C. Dai and G. F. Qin. Fungal Sci. 13:101, 1998. (2) E. M. Hansen et al. Species limits for Phellinus weirii. Pages 119-127 in: Root and butt rots of forest tress. Int. Conf. Root and Butt Rots, INRA, France, 1998. (3) M. J. Larsen et al. Mycologia 86:121, 1994.

Acute diarrhea during army field exercise in southern China

AIM

During emergency period, infectious diseases can be a major threat to military forces. During field training in southern China, diarrhea is the main cause of nonbattle injury. To evaluate the causes of and risk factors for diarrhea in emergency period, we collected clinical and epidemiological data from the People's Liberation Army (PLA) during field training in southern China.

METHODS

From September 25 to October 2 1997, 2636 military personnel were investigated. Fecal sample cultures for lapactic pathogens were obtained from 103 military personnel with diarrhea. In addition, a questionnaire was administered to 103 cases and 206 controls to evaluate the association between illness and potential risk factors. At the same time, another questionnaire of 1:4 case-case control was administered to 22 severe cases (each severe case paired 4 mild cases).

RESULTS

The training troop's diarrhea incidence rate was significantly higher than that of garrison. The diarrhea incidence rate of officers was significantly lower than that of soldiers. A lapactic pathogen was identified in 63.1% (65/103) of the troops with diarrhea. Enterotoxigenic Escherichia coli (35.0%) and plesiomona shigelloides (16.5%) were the most common bacterial pathogens. All bacterial isolates were sensitive to norfloxacin and ceftazidine. However, almost all of them were resistant to sulfamethoxazole, trimethoprim-sulfamethoxazole, oxytetracycline, doxycycline, furazolidone, ampicillin and cloromycetin to a different degree. Risk factors associated with diarrhea included drinking raw water, eating outside, contacting diarrhea patients, lacking sanitation, depression, lacking sleep, which were established by multiple-factor logistic regression analysis. In addition, the unit incidence rate was associated with the density of flies and the average daily boiled water available by regression and discriminate analysis.

CONCLUSION

A series of risk factors are associated with the incidence rate of diarrhea. Our results may provide a useful basis for prevention and cure of diarrhea in emergency period of PLA.

First Report of Heterobasidion parviporum (S Group of H. annosum sensu lato) on Tsuga spp. in Asia

Members of the Heterobasidion annosum (Fr.) Bref. complex are among the most important pathogens in coniferous forests of Europe and North America. Three intersterile groups (P, S, and F) have been found in this complex from Europe (1) and were recently segregated into three species based on intersterility, host preferences, and morphology (4). In a survey of wood-rotting fungi in China in 2002, Heterobasidion spp. were found on Tsuga chinensis (Franch.) Pritz and T. dumosa (D. Don) Eichl. in natural forests from the northern Sichuan Province of southwestern China (32°43' to 33°11' N, 103°50' to 103°53' E.). Basidiocarps of the fungus were relatively common on decayed wood in roots of dead trees, stumps, and fallen trunks. We collected four basidiocarps (Dai 4045, 4051, 4214, and 4224 in the Institute of Applied Ecology, Chinese Academy of Sciences, IFP) from three stands of mixed coniferous forests and made 40 homokaryotic, single-basidiospore cultures (02046, 02047, 02050, and 02051 in the Finnish Forest Research Institute). Two homokaryons from each basidiocarp were paired with homokaryotic tester strains of European H. annosum (P group), H. parviporum Niemelä & Korhonen (S group), and H. abietinum Niemelä & Korhonen (F group). The pairings showed that the progeny from the four basidiocarps are H. parviporum. The Chinese isolates did not form clamp connections with H. annosum sensu stricto, and a strong demarcation line developed in all these pairings. In contrast, the Chinese isolates formed clamp connections in almost every pairing with European H. parviporum, the clamp connections developed in both sides of the pairings, and no distinct demarcation line was present in most of these pairings. The Chinese homokaryons were also compatible with European H. abietinum, but in most of these pairings, clamp connections were found in the isolate from China but not in the European tester, and a demarcation line was present in most of the pairings. In contrast to H. annosum sensu stricto, the Chinese basidiocarps had smaller pores (4.5 to 6 per mm versus 3 to 4.5 per mm), and a thin tomentum on the pileal surface in contrast to the basidiocarps of H. abietinum. Previously, H. parviporum was found in Asia on coniferous hosts such as Abies, Larix, Picea and Pinus spp. (2). The North American S group of H. annosum sensu lato attacks species of Tsuga spp. in western North America (3), but to our knowledge, this is the first report of H. parviporum on native species of Tsuga spp. outside North America. References: (1) P. Capretti et al. Eur. J. For. Pathol. 20:231, 1990. (2) Y. C. Dai and K. Korhonen. Eur. J. For. Pathol. 29:273, 1999. (3) G. M. Filip and D. J. Morrison. North America. Pages 405-427 in: Heterobasidion annosum. Biology, Ecology, Impact and Control. CAB International, Wallingford, UK, 1998. (4) T. Niemelä and K. Korhonen. Taxonomy of the genus Heterobasidion. Pages 27-33 in: Heterobasidion annosum. Biology, Ecology, Impact and Control. CAB International, Wallingford, UK, 1998.

Ovarian fibrosarcoma with long-term survival: a case report

Primary ovarian fibrosarcoma is an exceedingly rare malignant ovarian stromal tumor which has a poor prognosis. We report here a 46-year-old woman who suffered from irregular vaginal bleeding for 2 months. She received hysterectomy and salpingo-oophorectomy due to a provisional diagnosis of uterine and ovarian tumors. At surgery, an 8-cm ovarian solid multilobular tumor was found. Frozen section examination revealed an ovarian fibrosarcoma. She then underwent staging procedures including intraperitoneal washing, cytology, and pelvic and para-aortic lymph node sampling. Final pathologic examination revealed that the tumor exhibited densely packed spindle cells in storiform configuration with obvious increased mitotic activity. In addition, the flow cytometric study showed marked elevated percentage of tumor cells in the S phase (13.1%). After surgery, the patient received six courses of combination chemotherapy with epirubicin, ifosfamide, and dacarbazine (DTIC). The patient stood the treatment well and is free from disease 6 years later.

Negative CLOtest pellet can be reused

BACKGROUND

The CLOtest is based on the production of ammonia from urea in the presence of urease. In theory, substrate that has not been consumed in a negative test can be reused.

METHODS

We collected negative CLOtest pellets after their first use and stored them at room temperature. Whenever a CLOtest was needed during endoscopy, two biopsy specimens were taken from the antrum. One specimen was tested with a new CLOtest and the other with one that had been used previously. Time to color change was observed in paired tests.

RESULTS

We used 216 previously used CLOtest pellets with biopsy specimens obtained from 317 patients. Of the paired tests, 204 matched positive and 108 tested negative. Only 5 paired tests had discrepant results. Three had positive results only with a new CLOtest, and 2 were positive only with the reused test. In positive paired tests, there was significant linear correlation in log-transformed color change time between reused and new tests (p < 0.001). Ninety-two percent of previously used pellets were reused fewer than three times before they yielded a positive color change; the interval to this occurrence ranged from 2 to 15 days. Compared with the new CLOtest, the sensitivity of the reused CLOtest was 98. 6% and the specificity was 98.2%.

CONCLUSIONS

A negative CLOtest kept at room temperature can be reused within a short period of time, in circumstances in which there are environmental and economic considerations to be taken into account.

Formation of lymphocyte colonies under serum-free culture conditions in normal individuals and patients with chronic lymphocytic leukemia

This paper describes a culture system which supports the formation of B cell and some T cell colonies under serum-free conditions in peripheral blood samples of normal individuals and patients with chronic lymphocytic leukemia (CLL) of B cell type. In this system, serum is replaced by bovine serum albumin, transferrin, cholesterol, insulin and catalase or horseradish peroxidase. In addition, it is necessary to add staphylococcus protein A, mitomycin-treated T cells as feeders and phytohemagglutinin leukocyte-conditioned medium as a source of growth factors. The plating efficiency is greatly enhanced when normal cells are incubated with galactose oxidase prior to plating and when CLL cells are exposed sequentially to neuraminidase and galactose oxidase.

B-lymphocyte colony formation in chronic lymphocytic leukemia

A semisolid culture system for B-cell colony formation is described. The system includes pretreatment of B-cells by neuraminidase-galactose oxidase and help of mitomycin-treated T-cells. With this assay system, colony-forming B-cell precursors were detected in all eight patients we studied with B-cell chronic lymphocytic leukemia. These patients' own T-cell helper effect was less than that of normal T-cells.