Cellular localization of severe acute respiratory syndrome coronavirus (SARS-CoV) in the lungs of patients with SARS is important in confirming the etiological association of the virus with disease ...as well as in understanding the pathogenesis of the disease. To our knowledge, there have been no comprehensive studies investigating viral infection at the cellular level in humans.
We collected the largest series of fatal cases of SARS with autopsy material to date by merging the pathological material from two regions involved in the 2003 worldwide SARS outbreak in Hong Kong, China, and Toronto, Canada. We developed a monoclonal antibody against the SARS-CoV nucleoprotein and used it together with in situ hybridization (ISH) to analyze the autopsy lung tissues of 32 patients with SARS from Hong Kong and Toronto. We compared the results of these assays with the pulmonary pathologies and the clinical course of illness for each patient. SARS-CoV nucleoprotein and RNA were detected by immunohistochemistry and ISH, respectively, primarily in alveolar pneumocytes and, less frequently, in macrophages. Such localization was detected in four of the seven patients who died within two weeks of illness onset, and in none of the 25 patients who died later than two weeks after symptom onset.
The pulmonary alveolar epithelium is the chief target of SARS-CoV, with macrophages infected subsequently. Viral replication appears to be limited to the first two weeks after symptom onset, with little evidence of continued widespread replication after this period. If antiviral therapy is considered for future treatment, it should be focused on this two-week period of acute clinical disease.
We have monitored Epstein-Barr virus (EBV) IgA antibody levels of 39 nasopharyngeal carcinoma (NPC) cases for up to 15 years before clinical onset of NPC, and assessed preclinical serologic status of ...another 68 cases. Our results identify a serologic window preceding diagnosis when antibody levels are raised and sustained. This window can persist for as long as 10 years, with a mean duration estimated to as 37+/-28 months. Ninety-seven of these 107 NPC cases exhibited such a window. Cases that did not may reflect individual antibody response to EBV. Serologic screening at enrollment identified those cases who had already entered the window and became clinically manifested earlier (median=28 months) than those who entered the window after enrollment (median=90 months). The former account for 19 of 21 cases diagnosed within 2 years of screening. Nasopharyngeal carcinoma risk levels among seropositive subjects were also highest during this period. Both prediction rates and risk levels declined thereafter; cases detected at later times were composed of increasing proportions of individuals who entered the serological window after screening. Our findings establish EBV antibody as an early marker of NPC and suggest that repeated screening to monitor cases as they enter this window has considerable predictive value, with practical consequences for cancer treatment.
Otitis media (OM) is common in young children and can cause hearing loss and speech, language, and developmental delays. OM has high heritability; however, little is known about OM-related molecular ...and genetic processes.
CDHR3
was previously identified as a locus for OM susceptibility, but to date, studies have focused on how the
CDHR3
p.Cys529Tyr variant increases epithelial binding of rhinovirus-C and risk for lung or sinus pathology. In order to further delineate a role for
CDHR3
in OM, we performed the following: exome sequencing using DNA samples from OM-affected individuals from 257 multi-ethnic families; Sanger sequencing, logistic regression and transmission disequilibrium tests for 407 US trios or probands with OM; 16S rRNA sequencing and analysis for middle ear and nasopharyngeal samples; and single-cell RNA sequencing and differential expression analyses for mouse middle ear. From exome sequence data, we identified a novel pathogenic
CDHR3
splice variant that co-segregates with OM in US and Finnish families. Additionally, a frameshift and six missense rare or low-frequency variants were identified in Finnish probands. In US probands, the
CDHR3
p.Cys529Tyr variant was associated with the absence of middle ear fluid at surgery and also with increased relative abundance of
Lysobacter
in the nasopharynx and
Streptomyces
in the middle ear. Consistent with published data on airway epithelial cells and our RNA-sequence data from human middle ear tissues,
Cdhr3
expression is restricted to ciliated epithelial cells of the middle ear and is downregulated after acute OM. Overall, these findings suggest a critical role for
CDHR3
in OM susceptibility.
Key messages
• Novel rare or low-frequency
CDHR3
variants putatively confer risk for otitis media.
• Pathogenic variant
CDHR3
c.1653 + 3G > A was found in nine families with otitis media.
•
CDHR3
p.Cys529Tyr was associated with lack of effusion and bacterial otopathogens.
•
Cdhr3
expression was limited to ciliated epithelial cells in mouse middle ear.
•
Cdhr3
was downregulated 3 h after infection of mouse middle ear.
It has been difficult to define the burden of influenza in children because of confounding by the cocirculation of respiratory syncytial virus (RSV). In Hong Kong, China, the influenza and RSV ...infection seasons sometimes do not overlap, thus providing an opportunity to estimate the rate of influenza-related hospitalization in a defined population, free from the effects of RSV.
In a retrospective, population-based study, we estimated the influenza-associated excess rate of hospitalization among children 15 years old or younger in the Hong Kong Special Administrative Region from 1997 to 1999. Data from a single hospital with intensive use of virologic analyses for diagnosis were obtained to define and adjust for underestimation of the model.
Peaks of influenza and RSV infection activity were well separated in 1998 and 1999 but overlapped in 1997. The adjusted rates of excess hospitalization for acute respiratory disease that were attributable to influenza were 278.5 and 288.2 per 10,000 children less than 1 year of age in 1998 and 1999, respectively; 218.4 and 209.3 per 10,000 children 1 to less than 2 years of age; 125.6 and 77.3 per 10,000 children 2 to less than 5 years of age; 57.3 and 20.9 per 10,000 children 5 to less than 10 years of age; and 16.4 and 8.1 per 10,000 children 10 to 15 years of age.
In the subtropics, influenza is an important cause of hospitalization among children, with rates exceeding those reported for temperate regions.
Abstract Background Myasthenia gravis (MG) is an organ-specific autoimmune disease characterized by autoantibody-mediated impairment of skeletal muscle neuromuscular transmission. MG causes ...significant morbidity and even mortality. We studied the long-term clinical outcome of generalized MG (gMG) patients. Methods Records of Chinese gMG patients managed in Queen Mary Hospital from 1997 to 2012 were reviewed. Clinical, serological and radiological characteristics were studied for independent predictors of good long-term clinical outcome. Results A total of 123 Chinese gMG patients were studied. Their mean onset age was 44.8 years (range 7–83 years), 87 (70.7%) were female, and median follow-up duration was 114 months (interquartile range 67–188 months). Thymoma were detected in 45 patients (36.6%). Acetylcholine receptor autoantibodies were detected in 99 patients (87.6%). Ninety-three patients (75.6%) received immunosuppressant therapy (corticosteroid 75.6%, azathioprine 58.5%, mycophenolate mofetil 5.7%, cyclosporin 5.7%) and 77 (62.6%) received thymectomy. Thirty-five (28.5%) patients experienced MG crisis and two died. Ninety-six (78.0%) patients had good outcome defined by Myasthenia Gravis Foundation of America (MGFA) post-intervention status (PIS) of complete stable remission (CSR), pharmacological remission (PR) or minimal manifestation (MM) at latest follow-up, whereas 24 patients (19.5%) had intermediate outcome defined by MGFA PIS of Improved (I); 3 patients (2.4%) had poor prognosis defined by MGFA PIS of unchanged (U), worse (W), exacerbation (E) or died of MG (D). Azathioprine therapy was the only independent predictor of good outcome (OR 3.57, 95% CI 1.05–12.10, p = 0.042). Conclusion 78.0% of gMG patients had good long-term clinical outcome. Azathioprine therapy independently predicted good clinical outcome.
Reliable estimates of the burden of 2009 pandemic influenza A(pH1N1) cannot be easily obtained because only a small fraction of infections were confirmed by laboratory tests in a timely manner. In ...this study we developed a Poisson prediction modelling approach to estimate the excess mortality associated with pH1N1 in 2009 and seasonal influenza in 1998–2008 in the subtropical city Hong Kong. The results suggested that there were 127 all-cause excess deaths associated with pH1N1, including 115 with cardiovascular and respiratory disease, and 22 with pneumonia and influenza. The excess mortality rates associated with pH1N1 were highest in the population aged ⩾65 years. The mortality burden of influenza during the whole of 2009 was comparable to those in the preceding ten inter-pandemic years. The estimates of excess deaths were more than twofold higher than the reported fatal cases with laboratory-confirmed pH1N1 infection.
BackgroundRecently, we described the discovery of a novel group 2 coronavirus, coronavirus HKU1 (CoV-HKU1), from a patient with pneumonia. However, the clinical and molecular epidemiological features ...of CoV-HKU1–associated pneumonia are unknown MethodsProspectively collected (during a 12-month period) nasopharyngeal aspirates (NPAs) from patients with community-acquired pneumonia from 4 hospitals were subjected to reverse-transcription polymerase chain reaction, for detection of CoV-HKU1. The epidemiological, clinical, and laboratory characteristics of patients with CoV-HKU1–associated pneumonia were analyzed. The pol spike (S), and nucleocapsid (N) genes were also sequenced ResultsNPAs from 10 (2.4%) of 418 patients with community-acquired pneumonia were found to be positive for CoV-HKU1. All 10 cases occurred in spring and winter. Nine of these patients were adults, and 4 had underlying diseases of the respiratory tract. In the 6 patients from whom serum samples were available, all had a 4-fold change in immunoglobulin (Ig) G titer and/or presence of IgM against CoV-HKU1. The 2 patients who died had significantly lower hemoglobin levels, monocyte counts, albumin levels, and oxygen saturation levels on admission and had more-extensive involvement visible on chest radiographs. Sequence analysis of the pol S, and N genes revealed 2 genotypes of CoV-HKU1 ConclusionsCoV-HKU1 accounts for 2.4% of community-acquired pneumonia, with 2 genotypes in the study population. Without performance of diagnostic tests, the illness was clinically indistinguishable from other community-acquired pneumonia illnesses
Severe acute respiratory syndrome (SARS) is a newly emerged disease caused by a novel coronavirus (SARS-CoV), which spread globally in early 2003, affecting over 30 countries. We have used molecular ...epidemiology to define the patterns of spread of the virus in Hong Kong and beyond.
The case definition of SARS was based on that recommended by WHO. We genetically sequenced the gene for the S1 unit of the viral spike protein of viruses from patients with SARS in Hong Kong (138) and Guangdong (three) in February to April, 2003. We undertook phylogenetic comparisons with 27 other sequences available from public databases (Genbank).
Most of the Hong Kong viruses (139/142), including those from a large outbreak in an apartment block, clustered closely together with the isolate from a single index case (HKU-33) who came from Guangdong to Hong Kong in late February. Three other isolates were genetically distinct from HKU-33 in Hong Kong during February, but none of these contributed substantially to the subsequent local outbreak. Viruses identified in Guangdong and Beijing were genetically more diverse.
The molecular epidemiological evidence suggests that most SARS-CoV from the outbreak in Hong Kong, as well as the viruses from Canada, Vietnam, and Singapore, are genetically closely linked. Three viruses found in Hong Kong in February were phylogenetically distinct from the major cluster, which suggests that several introductions of the virus had occurred, but that only one was associated with the subsequent outbreak in Hong Kong, which in turn spread globally.
Atrazine (ATZ), 2-chloro-4-(ethylamino)-6-(isopropylamino)-
s-triazine, was effectively degraded by hydroxyl radicals that were generated by Fe
II/H
2O
2 in the Fenton's process. Up to 98% ATZ ...removal can be achieved in the process if the doses of Fe
II and H
2O
2 are selected appropriately. Oxidation capacity of the process was successfully predicted through a kinetic approach with three simple and measurable parameters (i.e., two rate constants and a break point time), which makes the model useful in predicting, controlling and optimizing the degradation of ATZ. In addition, the transformation pathways of ATZ decay was successfully investigated by using a novel technology, liquid chromatography electrospray tandem mass spectrometry (LC/ESI-MS/MS). Ten intermediates were identified in the process. The alkylic-oxidation followed by dealkylation and/or dechlorination–hydroxylation were found to be the major pathways of the decay of ATZ in Fenton's process. All the detected intermediates were found to be dealkylated in different levels or positions. The dealkylated species may be further dechlorinated but generally at a lower fraction (<10%) due to the depletion of oxidants.
Laribacter hongkongensis is a newly discovered, facultative anaerobic, Gram-negative, motile, sea gull-shaped rod associated with freshwater fish borne gastroenteritis and traveler's diarrhea. A ...highly reproducible and discriminative typing system is essential for better understanding of the epidemiology of L. hongkongensis. In this study, a multilocus sequence typing (MLST) system was developed for L. hongkongensis. The system was used to characterize 146 L. hongkongensis isolates, including 39 from humans and 107 from fish.
Fragments (362 to 504 bp) of seven housekeeping genes were amplified and sequenced. Among the 3068 bp of the seven loci, 332 polymorphic sites were observed. The median number of alleles at each locus was 34 range 22 (ilvC) to 45 (thiC). All seven genes showed very low d(n)/d(s) ratios of < 0.04, indicating that no strong positive selective pressure is present. A total of 97 different sequence types (STs) were assigned to the 146 isolates, with 80 STs identified only once. The overall discriminatory power was 0.9861. eBURST grouped the isolates into 12 lineages, with six groups containing only isolates from fish and three groups only isolates from humans. Standardized index of association (I(S)(A)) measurement showed significant linkage disequilibrium in isolates from both humans and fish. The I(S)(A) for the isolates from humans and fish were 0.270 and 0.636, indicating the isolates from fish were more clonal than the isolates from humans. Only one interconnected network (acnB) was detected in the split graphs. The P-value (P = 0) of sum of the squares of condensed fragments in Sawyer's test showed evidence of intragenic recombination in the rho, acnB and thiC loci, but the P-value (P = 1) of maximum condensed fragment in these gene loci did not show evidence of intragenic recombination. Congruence analysis showed that all the pairwise comparisons of the 7 MLST loci were incongruent, indicating that recombination played a substantial role in the evolution of L. hongkongensis. A website for L. hongkongensis MLST was set up and can be accessed at http://mlstdb.hku.hk:14206/MLST_index.html.
A highly reproducible and discriminative MLST system was developed for L. hongkongensis.
PDF
