Laboratory Diagnosis & Treatment

Laboratory Diagnosis

Diagnostic tests are available at all public health laboratories and many clinical laboratories.

Real-Time PCR Assays

Real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) is the most widely used diagnostic assay for detecting norovirus. This assay detects the genetic material (RNA) of the virus. It can be used to test stool, vomitus, and environmental specimens.

The best way to detect norovirus is in stool specimens collected when a person has acute illness (within 48 to 72 hours after they get symptoms). Norovirus can sometimes be found in stool specimens collected 2 weeks after a person recovers.

Other Methods

Several enzyme immunoassays (EIAs) for detecting norovirus in stool samples are available. The Food and Drug Administration has cleared an EIA for detecting norovirus during outbreaks. EIAs are currently not sensitive enough (<50%) for diagnosing individual cases.

Genetic characterization of norovirus strains found in stool and environmental samples has been very useful in epidemiologic investigations by—

• linking cases to each other, and
• suggesting a common source.

Treatment

There is no specific therapy to treat people with gastroenteritis caused by norovirus infection.

Dehydration is the most common complication that may require medical care. Treatment includes replacing fluids lost from vomiting and diarrhea and correcting electrolyte disturbances. Oral rehydration fluids and giving fluids intravenously are used for severe dehydration.

Avoid giving antimotility agents to children younger than 3 years old. However, these agents may be helpful in older children and adults, particularly when used along with rehydration treatment. Antiemetic agents generally should be given to adults only. Antibiotics are of no benefit in treating norovirus infections.

More norovirus information for health care providers:

• Clinical Overview
• Preventing Norovirus Infection