LAC virus is difficult to isolate from clinical samples, and almost all isolates (and positive PCR results) have come from brain tissue or rarely CSF. In the absence of a sensitive and non-invasive virus detection method, serologic testing remains the primary method for diagnosing LAC virus infection. All LAC virus disease cases should be reported to local or state public health authorities.
Laboratory diagnosis is generally accomplished by testing of serum or CSF to detect LAC virus-specific IgM and neutralizing antibodies. LAC virus IgM tests are available commercially, in some state health department laboratories, and at CDC. Because of potential cross-reactivity in the IgM assay to related viruses (e.g., Jamestown Canyon), a positive LAC virus IgM test result should be confirmed by neutralizing antibody testing of serum specimens at a state public health laboratory or CDC. To submit specimens for testing at CDC, please contact your state health department.
Viral cultures and tests to detect viral RNA (e.g., reverse transcriptase-polymerase chain reaction [RT-PCR]) can be performed on serum, CSF, and tissue specimens collected early in the course of illness and, if results are positive, can confirm an infection. Immunohistochemistry (IHC) can detect LAC virus antigen in formalin-fixed tissue. Negative results of these tests do not rule out LAC virus infection. Viral culture, RT-PCR, and IHC can be requested through state public health laboratories or CDC.
Contact your state or local health department for assistance with diagnostic testing. They can assist you with determining if samples should be sent to the CDC Arbovirus Diagnostic Laboratory for further testing.
- Instructions for Submitting Diagnostic Specimens to the DVBD Arbovirus Diagnostic Laboratory
- CDC Data and Specimen Handling (DASH) Section Form 50.34 for Submission of Laboratory Specimens
ALL RESULTS WILL BE SENT TO THE APPROPRIATE STATE HEALTH DEPARTMENT. Specimens should be submitted to CDC through state health departments.