Viral Loads in Clinical Specimens and SARS Manifestations

Hung, Ivan Fan-Ngai; Cheng, Vincent Chi-Chung; Wu, Alan; Tang, Bone Siu-Fai; Chan, Kwok Hung; Chu, Chung Ming; Wong, Maureen Mo-Lin; Hui, Wai-Ting; Poon, Leo L. M.; Tse, Doris M.W.; Chan, Kwok-Hung; Woo, Patrick C. Y.; Lau, Susanna K. P.; Peiris, J. S. Malik; Yuen, Kwok‐Yung

doi:10.3201/eid1009.040058

Cited by 273 publications

(281 citation statements)

References 27 publications

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“…In our series, lymphopenia was more common among patients with severe disease, as seen in SARS coronavirus infection [33]. Furthermore, an inverse correlation between lymphocyte count and viral load in both the nasopharyngeal and endotracheal specimens was observed.…”

Section: Discussionmentioning

confidence: 56%

Delayed Clearance of Viral Load and Marked Cytokine Activation in Severe Cases of Pandemic H1N1 2009 Influenza Virus Infection

et al. 2010

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Section: Discussionmentioning

confidence: 56%

Delayed Clearance of Viral Load and Marked Cytokine Activation in Severe Cases of Pandemic H1N1 2009 Influenza Virus Infection

et al. 2010

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“…Quantitative studies of viral shedding in SARS patients provide some hints into the pathogenesis of the disease. Compared with other respiratory viral infections, such as influenza, SARS had a longer incubation period (mean 4.6 days, variance 15.9 days) (25), and the viral load in the upper respiratory tract, including nasopharyngeal aspirates and throat swabs, was low during the first 4 days and peaked at 10 5.8 copies/mL in nasopharyngeal aspirates 10 days after the onset of disease (19, 86,87). However, nasopharyngeal viral titers did not always accurately reflect viral load in the lungs.…”

Section: Viral Replicationmentioning

confidence: 98%

The Immunobiology of SARS

Chen

Subbarao

2007

Annu. Rev. Immunol.

266

277

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Severe acute respiratory syndrome (SARS) presented as an atypical pneumonia that progressed to acute respiratory distress syndrome in approximately 20% of cases and was associated with a mortality of about 10%. The etiological agent was a novel coronavirus (CoV). Angiotensin-converting enzyme 2 is the functional receptor for SARS-CoV; DC-SIGN and CD209L (L-SIGN) can enhance viral entry. Although the virus infects the lungs, gastrointestinal tract, liver, and kidneys, the disease is limited to the lungs, where diffuse alveolar damage is accompanied by a disproportionately sparse inflammatory infiltrate. Pro-inflammatory cytokines and chemokines, particularly IP-10, IL-8, and MCP-1, are elevated in the lungs and peripheral blood, but there is an unusual lack of an antiviral interferon (IFN) response. The virus is susceptible to exogenous type I IFN but suppresses the induction of IFN. Innate immunity is important for viral clearance in the mouse model. Virus-specific neutralizing antibodies that develop during convalescence prevent reinfection in animal models.

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“…Only the earliest NPA specimen was tested if multiple specimens were available from the same patient. NPA specimens were collected as described previously (8). Clinical and laboratory data were obtained using the clinical management system.…”

mentioning

confidence: 99%

Use of Nasopharyngeal Aspirate for Diagnosis of Pneumocystis Pneumonia

Wong

et al. 2013

J Clin Microbiol

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Quantitative PCR on nasopharyngeal aspirate (NPA) can achieve high sensitivity and specificity in diagnosing Pneumocystis pneumonia (PCP) compared to microscopic examination of bronchoscopic specimens in a population with low HIV prevalence. Since NPA is a minimally invasive procedure, it is ideal as a screening test for PCP. C urrently, microbiological confirmation of Pneumocystis pneumonia (PCP) requires the identification of Pneumocystis cysts or trophozoites using microscopy. Bronchoscopic specimens are preferred because Pneumocystis resides mainly in the alveolar space (1). However, both transbronchoscopic bronchoalveolar lavage and sputum induction pose significant risk to the patient (2-4). Upper respiratory tract specimens are not recommended because of low sensitivity when traditional microscopic examination is used (5). PCR has higher sensitivity than microscopic examination in the detection of Pneumocystis (6) and may overcome the problem of low sensitivity associated with microscopic examination of upper respiratory tract specimens. In this study, we sought to determine whether nasopharyngeal aspirate (NPA) specimens could be used for the diagnosis of PCP.Patients of the Hong Kong West Cluster Hospitals with bronchoscopic specimens (bronchoalveolar lavage fluid [BALF] or bronchial aspirate) submitted to our laboratory for Pneumocystis examination from 1 January 2010 to 31 March 2012 were identified using the laboratory information system. In our laboratory, Pneumocystis cysts were visualized with methenamine silver stain by using standard procedures (7). With this method, Pneumocystis trophozoites or sporozoites could not be detected. Archived NPA specimens from these patients collected during the same hospitalization were retrieved. Only the earliest NPA specimen was tested if multiple specimens were available from the same patient. NPA specimens were collected as described previously (8). Clinical and laboratory data were obtained using the clinical management system. Patients without archived NPA specimens were excluded. A patient was considered to have definite PCP if Pneumocystis was identified in the bronchoscopic specimen by microscopic examination (9). This study has been approved by the Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster.DNA was extracted from 200 l of NPA specimens and from other fungi using the QIAamp DNA kit (Qiagen, Hilden, Germany) and DNeasy plant minikit (Qiagen, Hilden, Germany), respectively, according to the manufacturer's instructions (10). Real-time quantitative PCR (qPCR) targeting a 124-bp fragment of the mitochondrial large subunit rRNA (mt LSU rRNA) gene of Pneumocystis jirovecii was performed as described previously (11). Plasmid suspensions were used as standards for quantification and positive controls (Fig. 1).We verified the positive results from the mitochondrial (mt) large-subunit (LSU) rRNA qPCR (LSU-qPCR) by a conventional PCR targeting the mitochondrial small-subunit rRNA (mt SSU rRNA) gene of P. jiro...

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Viral Loads in Clinical Specimens and SARS Manifestations

Abstract: The number of anatomical sites with detectable viral loads by RT-qPCR appeared to correlate with death risk.

Cited by 273 publications

References 27 publications

Delayed Clearance of Viral Load and Marked Cytokine Activation in Severe Cases of Pandemic H1N1 2009 Influenza Virus Infection

Delayed Clearance of Viral Load and Marked Cytokine Activation in Severe Cases of Pandemic H1N1 2009 Influenza Virus Infection

The Immunobiology of SARS

Use of Nasopharyngeal Aspirate for Diagnosis of Pneumocystis Pneumonia

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