TEST CATALOG ORDERING & RESULTS SPECIMEN HANDLING CUSTOMER SERVICE EDUCATION & INSIGHTS
Test Catalog

Test ID: CAVPC    
California Virus (La Crosse) Encephalitis Antibody Panel, IgG and IgM, Spinal Fluid

Useful For Suggests clinical disorders or settings where the test may be helpful

Aiding in the diagnosis of California (La Crosse) encephalitis using spinal fluid specimens

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

See Mosquito-borne Disease Laboratory Testing in Special Instructions.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

California (La Crosse) virus is a member of the Bunyaviridae family and it is one of the arthropod-borne encephalitides. It is transmitted by various Aedes and Culex mosquitoes and is found in such intermediate hosts as the rabbit, squirrel, chipmunk, and field mouse.

 

California meningoencephalitis is usually mild and occurs in late summer. Ninety percent of infections are seen in children less than 15 years of age, usually from rural areas. The incubation period is estimated to be 7 days and acute illness lasts 10 days or less in most instances. Typically, the first symptoms are nonspecific, lasting 1 to 3 days, and are followed by the appearance of central nervous system (CNS) signs and symptoms such as stiff neck, lethargy, and seizures, which usually abate within 1 week. Symptomatic infection is almost never recognized in those over 18 years old. The most important sequela of California virus encephalitis is epilepsy, which occurs in about 10% of children and almost always in patients who have had seizures during the acute illness. An estimated 2% of patients have persistent paresis. Learning disabilities or other objective cognitive deficits have been reported in a small proportion (<2%) of patients. Learning performance and behavior of most recovered patients are not distinguishable from comparison groups in these same areas.

 

Infections with arboviruses can occur at any age. The age distribution depends on the degree of exposure to the particular transmitting arthropod relating to age, sex, and occupational, vocational, and recreational habits of the individuals. Once humans have been infected, the severity of the host response may be influenced by age. Serious California (La Crosse) virus infections primarily involve children, especially boys. Adult males exposed to California viruses have high prevalence rates of antibody but usually show no serious illness. Infection among males is primarily due to working conditions and sports activities taking place where the vector is present.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

IgG: <1:1

IgM: <1:1

Reference values apply to all ages.

Interpretation Provides information to assist in interpretation of the test results

A positive result indicates intrathecal synthesis of antibody and is indicative of neurological infection.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

All results must be correlated with clinical history and other data available to the attending physician.

 

False-positive results may be caused by breakdown of the blood-brain barrier, or by the introduction of blood into the cerebrospinal fluid at collection.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Gonzalez-Scarano F, Nathanson N: Bunyaviruses. In: Fields BM, Knipe DM, eds. Fields Virology. Vol. 1. 2nd ed. Raven Press, 1990; 1195-1228

2. Donat JF, Rhodes KH, Groover RV, Smith TF: Etiology and outcome in 42 children with acute nonbacterial meningoencephalitis. Mayo Clin Proc. 1980:55:156-160

3. Tsai TF: Arboviruses. In: Murray PR, Baron EF, Pfaller MA, et al, eds. Manual of Clinical Microbiology. 7th ed. ASM Press; 1999: 1107-1124

4. Calisher CH: Medically important arboviruses of the United States and Canada. Clin Microbiol Rev. 1994;7:89-116

5. Beckham JD, Tyler KL: Arbovirus Infections. Continuum (Minneap Minn). 2015 Dec;21(6 Neuroinfectious Disease):1599-1611. doi: 10.1212/CON.0000000000000240

6. Dolin R: California encephalitis, hantavirus pulmonary syndrome, hantavirus hemorrhagic fever with renal syndrome, and bunyavirus hemorrhagic fevers. In Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:2169-2176

Special Instructions Library of PDFs including pertinent information and forms related to the test