Nov. 21, 2007 Using a rapid, sensitive, and inexpensive diagnostic tool called MassTag PCR, scientists at Columbia University Mailman School of Public Health's Center for Infection and Immunity implicated a new human rhinovirus as the cause of severe pediatric respiratory tract infections in Europe.
The research team used MassTag PCR to investigate 97 samples, collected over a three-year period, from children with hospital-admitted, acute respiratory illness wherein no pathogen was identified through routine laboratory testing. Human rhinoviruses were the most frequent viruses detected in the sample set representing 75% of the identified viruses.
Human rhinoviruses are frequent causes of respiratory illness worldwide. Although they are most commonly associated with self-limited upper respiratory tract disease, lower respiratory tract infections related to HRV are being increasingly reported in infants, elderly persons, and immunocompromised patients. HRVs are also implicated in exacerbations of asthma, chronic bronchitis, and acute bronchiolitis.
"Acute respiratory infection is a significant cause of morbidity and mortality in children worldwide. Accurate identification of causative agents is critical to case management and to prioritization in vaccine development," stated W. Ian Lipkin, MD, professor of Epidemiology, Neurology, and Pathology at Columbia University, director of the Center for Infection and Immunity at the Mailman School of Public Health, and senior author of the paper.
In up to 50% of cases of severe respiratory disease, a causative agent is not identified, despite the application of PCR assays as well as classical diagnostic methods including culture, antigen tests, and serology. Broad-range molecular systems pioneered by this team including MassTag PCR, GreeneChips and high throughput metagenomic sequencing, enable pathogen discovery, surveillance and medical diagnostics. Recent application of these technologies led to diagnosis of viral hemorrhagic fevers in Africa, a new virus causing transplant deaths, and detection of Israel Acute Paralysis Virus in honey bees with Colony Collapse Disorder.
To detect pathogens, MassTag PCR uses small molecular tags to detect up to 30 different pathogens simultaneously in one test. Genetic material from a throat swab or other sample is extracted and then mixed with PCR primers--short pieces of DNA that recognize specific nucleic acid sequences within the genomes of the target viruses or bacteria. If a throat swab contains pathogens with nucleic acid sequences that match those of the primers, then the primers will copy the target DNA several million times. Likewise the molecular tags, different in mass for each of the primers, are also amplified making them easily detectable by mass spectrometry, a technology that identifies molecules based on their masses.
"The results of the study confirm our earlier findings in New York, namely, that these viruses represent a clinically significant but previously unappreciated species within the entero-/rhinoviruses, one of the longest known and most intensely studied virus groups," stated Thomas Briese, PhD, associate professor of clinical Epidemiology, who coordinated the study. "We urgently need drugs and vaccines to address the challenges they pose to child health."
In an editorial commentary in the December 15 issue of the Journal of Infectious Diseases, Anne Moscona, MD, departments of Pediatrics and of Microbiology and Immunology, Weill Medical College of Cornell University, states that the work of Dr. Lipkin's team with MassTag PCR, "provides a paradigm for new detection strategies for early recognition and containment of a wide range of respiratory pathogens."
Their findings are published in the December 15 issue of the Journal of Infectious Diseases (currently available online).
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The above story is based on materials provided by Columbia University's Mailman School of Public Health.
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