43rd ICAAC
A meeting of the American Society for Microbiology

September 14-17, 2003, Chicago, IL

 For more information on any presentation at the 43rd ICAAC contact Jim Sliwa, ASM Office of Communications at jsliwa@asmusa.org

 

NOTE:  ALL NEWS REPORTS ARE EMBARGOED UNTIL DATE AND TIME OF PRESENTATION

EMBARGOED UNTIL:  Sunday, September 14, 11:30 a.m.

(Session 14, Paper V-173)

Arlene Collins
State University of New York at Buffalo
Buffalo, NY 
Phone: 716-829-2161
acollins@buffalo.edu

We present a case in which human coronavirus was detected in the cerebrospinal fluid of a child presumed to have acute disseminated encephalomyelitis. In murine models, coronavirus has been found to cause a chronic demyelinating condition that resembles multiple sclerosis. Further, there is evidence of human coronavirus’s ability to infect neural cells in culture. This case report provides further support for the hypothesis that coronavirus may be an important etiologic factor in the pathogenesis of demyelinating disease in humans.

Drs. Arlene Collins, Ann Yeh and Howard Faden of the Departments of Microbiology, Neurology and Pediatrics at the State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo New York, USA, following investigations funded in part by a research award from SUNY at Buffalo/UUP, report a case of demyelinating disease in a child in which cerebrospinal fluid (CSF) and nasopharyngeal specimens were positive for human coronavirus by PCR, and in whom a four-fold rise in antibody titer was documented. All other testing for infectious agents was negative. Their findings are reported at the 43rd Interscience Conference on Antimicrobial Agents and Chemotherapy held in Chicago, IL, USA on September 14, 2003.

Acute disseminated encephalomyelitis (ADEM) is a single episode of demyelinating disease of the central nervous system that primarily affects children and young adults. It is characterized by high signal-intensity lesions in the white matter of the brain and spinal cord on magnetic resonance imaging (MRI). These lesions may be independent of the clinical findings. Children may experience alterations in brain function, seizures, blurred vision, paralysis on one side of the body, and/or symptoms suggestive of spinal cord transection.

Case Presentation

A 15-year-old previously healthy boy presented in January 2003 to the Women’s and Children’s Hospital of Buffalo after a 5 day history of numbness in the lower extremities. The numbness started in the lower legs and progressed to the umbilicus. He reported difficulty walking approximately 1 day before admission. He also reported clumsiness in his right hand. His mother noted increased irritability. The patient and his mother denied visual changes, seizure, headache, mental status changes, bowel or bladder dysfunction, or speech or language difficulties. There was no history of toxin ingestion. There was a history of an upper respiratory tract illness approximately 1 week before his first symptom. His brother had experienced a sore throat 1 to 2 weeks before the hospitalization. Physical examination revealed mild weakness in the right hand and foot. Heel-to-toe walking was poor. An MRI of the brain and spinal cord was performed the morning after admission. It demonstrated lesions in the white matter tracts in the cerebral cortex, in the left cerebellum and in the spinal cord. The patient’s symptoms resolved over several weeks without any therapeutic intervention.

Laboratory Results

Coronavirus OC43 was detected in the CSF and nasopharyngeal secretions by PCR technology*. Antibody titers to coronavirus OC43 rose from 1:160 in acute serum to 1:640 in convalescent serum (3 weeks later) **.

*Laboratory Methods for Coronavirus RT-PCR

Total RNA was extracted from 0. 250ml of the CSF and nasopharyngeal secretions and used for RT-PCR. A nested RT-PCR was carried out in a single tube with primers that were known to amplify a region of the nucleoprotein gene of human coronaviruses OC43 and 229E. Amplified products were detected by agarose gel electrophoresis and ethidium bromide staining. Samples that showed a DNA band of the appropriate size on agarose gels were cloned into a cloning plasmid and sequenced. Nasopharyngeal and cerebrospinal samples were considered as positive when sequencing revealed a ›95% sequence correspondence to the standard virus.

**Laboratory Methods for Immunofluorescence antibody assay for Coronavirus

Slides of coronavirus OC43-infected culture cells were used for indirect fluorescent antibody assay. Slides were incubated with twofold dilutions of acute and convalescent patient serum (20 days apart) for 60 minutes at 37ºC. Rabbit anti-human IgG (Fab')2 fluorescein conjugate diluted 1:20 was used for fluorescent staining. The positive control was a human serum with a known neutralizing antibody titer of 320 to human coronavirus OC43. The negative control was an IgG-deficient human serum (134mg/dL).

Discussion

This is the first reported case of coronavirus associated with demyelinating disease in a pediatric patient. The vast majority of cases have no diagnosed infected agent associated with this neurologic disease. Coronaviruses are common causes of upper respiratory tract infections in adults and children and generally produce mild disease. Most recently, a newly described variant of coronavirus has been associated with severe acute respiratory syndrome, or SARS . Coronaviruses are distributed worldwide. They are RNA viruses, enveloped with lipid-soluble coats, and are pleomorphic. Outbreaks tend to occur in winter and spring, with young children having the highest infection rates. These viruses are difficult to diagnose because they cannot be easily cultured.

Does coronavirus play a role in the pathogenesis of ADEM? What is the mechanism by which demyelination might occur after infection with coronavirus? The cause of ADEM and other demyelinating disorders, of course, is probably multifactorial, with both environmental and genetic factors playing important roles.

 

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