Virology / Serology - Arbovirus
General Information
Historically, North Carolina has been an area endemic for several arboviruses (insect transmitted diseases) most notably Eastern Equine Encephalitis (EEE) and LaCrosse Encephalitis viruses (LAC). These mosquito-borne viruses appear to be increasing in activity within the last decade. There was a record, 14 cases of LaCrosse encephalitis detected in 2001, mostly in children from the western part of N.C. where LAC is endemic. The actual number of LAC infections is thought to be considerably higher with the majority of infections going undetected or misdiagnosed.
Another arbovirus is now establishing itself within our state. West Nile Virus (WNV) first appeared in the western hemisphere in New York in 1999 and has spread rapidly. In 1999, WNV was detected in 4 states. In 2000, WNV had spread to 13 states. By 2001 WNV activity had been detected in 28 states. (For detailed distribution of WNV in the U.S. please visit the US Geological Survey website for maps of human, wild bird, horse and mosquito data reported to the CDC at http://www.nwhc.usgs.gov/disease_information/west_nile_virus/wnv_map.jsp
WNV was first detected in N.C. in one sick crow from Chatham County in 2000. In 2001, 17 West Nile virus infections were detected in NC, including: eight dead wild birds (two blue jays and six crows); three sentinel chickens; and six horses. For updated 2002 case counts please visit the NCDENR Public Health Pest Management West Nile Virus - Confirmed Cases page http://www.deh.enr.state.nc.us/phpm/wnv/Confirmed_Cases/confirmed_cases.html
In humans, WNV usually causes mild flu-like illness that can include fever, headache, body aches, rash and swollen lymph glands. In more serious infections symptoms can include a severe headache, high fever, neck stiffness, disorientation, coma, convulsions, muscle weakness, paralysis and very rarely death. The incubation period is usually 3 to 15 days. In a minority of cases the disease may be severe, with central nervous system involvement. Seven of the 62 documented human cases in the NYC area in 1999 were fatal. In 2000, there were 21 human cases documented and all occurred in three northeastern states. In 2001, there were 66 human cases of WNV distributed over 10 states.
Laboratory Testing
Important Notice to Clinicians - Fact sheet discussing clinical, features, diagnosis and reporting, laboratory findings, and treatment. (PDF, 33 KB)
The 2002 arboviral season is expected to show increases in arboviral activity. Timely laboratory testing for WNV and other arboviral infections including Eastern Equine Encephalitis and LaCrosse Encephalitis is available at the State Laboratory of Public Health free of charge via serology, viral isolation, and molecular amplification. All positive results will be promptly telephoned to the submitting physician or hospital at the number provided. Serologic testing of acute and convalescent sera for antibody detection is available for these viruses. An acute serum specimen should be submitted when drawn along with the onset and specimen collection date. Also collect a convalescent serum two-three weeks after illness onset. CSF specimens can be submitted (only with a companion serum) for molecular amplification, virus cultivation in cell culture, and/or antibody level determination. In fatal cases submit, CNS tissue specimens (spinal cord, medulla, cerebellum, and hippocampus) for virus isolation and molecular amplification in addition to serum and CSF.
Virology specimens should be sent refrigerated while serological specimens do not require refrigeration. Specimen transportation to our laboratory is available via the state courier system for a nominal fee or the submitter can use the US Postal service. The submission forms are attached for Virology (DHHS #3431) for testing of tissue and CSF specimens and Serology (DHHS #3445) for testing of serum and CSF specimens. Please complete these forms thoroughly including onset date, collection date, symptoms, travel history and vaccination history. This information is crucial for accurate interpretation of results. For more information about the submission process please refer to the Virology acceptance policy and specimen shipping page.
Horses: Testing of horses is also available for serum, CSF and CNS specimens for EEE and WNV. Please submit specimens through the Rollins Animal Diagnostic Laboratory or use the forms above for submission of these samples. Be sure to complete forms completely including vaccination history since horse vaccines are available for EEE and WNV. In 2001, North Carolina had 11 horses infected with EEE and 7 with WNV. In addition, 2 ducks were positive with EEE.
Wild Birds: Dead wild bird surveillance has been a very important tool in identifying risk of WNV to the population. Please visit the North Carolina Department of Environment and Natural Resources, Public Health Pest Management (NCDENR-PHPM) website at http://www.deh.enr.state.nc.us/phpm/ for information on "Dead Bird" reporting and testing. Information on dead and/or dying birds should be reported by e-mail to ncwnv@ncmail.net or by calling the "Dead Bird Hotline" at 1-877-790-1747. Submission forms for Dead Wild Bird testing can be found on their web page. The State Laboratory tests crows, blue jays and raptors (i.e. hawks and owls) for WNV. Please submit these samples through NCDENR-PHPM.
Contacts
To contact the Virology/Serology laboratory of the N.C. State Laboratory of Public Health, call (919) 733-7544. For questions about West Nile and other arboviruses please ask for Todd McPherson or Kate Volpe.
Additional Information
For additional information on West Nile virus and other arboviruses please visit:
- Arthropod-Borne Zoonotic Diseases Workshop: http:/.state.nc.us/LabImprovement/labTraining.asp
- North Carolina Department of Environment and Natural Resources, Public Health PestManagement: http://www.deh.enr.state.nc.us/phpm/index.htm
- N.C. Epidemiology: www.epi.state.nc.us/epi/oee/wnv.html
- N.C. Department of Agriculture: www.ncagr.gov/vet/DiseaseAlerts.htm
- CDC-West Nile: www.cdc.gov/ncidod/dvbid/westnile/
- Spotlight-WNV prevention: www.cdc.gov/ncidod/dvbid/westnile/2002spotlight.htm
- Arboviruses: www.cdc.gov/ncidod/dvbid/arbor/
- LaCrosse: www.cdc.gov/ncidod/dvbid/arbor/lacfact.htm
- Eastern Equine Encephalitis: www.cdc.gov/ncidod/dvbid/arbor/eeefact.htm
- US Geological Survey maintains maps of human, wild bird, horse and mosquito data reported to the CDC: http://westnilemaps.usgs.gov/2002/
See also:
- About Virology / Serology
- Chlamydia
- HIV
- Hepatitis
- Syphilis
- Special Serology
- CDC Referral
- Arbovirus
- Norovirus
