V.  West Nile Virus: Prevention Information and Guidance for Clinicians

·  No human vaccine against West Nile virus (WNV) is currently available.

·  Education about reducing the risk of infection is important for all persons in transmission areas, but especially in the higher-risk populations (persons more than 50 years old and persons who are immunocompromised).

·  The primary prevention step recommended is the use of mosquito repellent when outdoors. Mosquitoes may bite through thin clothing, so spraying clothes with repellent containing permethrin or another EPA-registered repellent will give extra protection. These repellents are the most effective and the most studied.

·  Generally, the more active ingredient a repellent contains the longer it can protect from mosquito bites.

·  Repellents containing permethrin are not approved for direct application on the skin. Repellent should not be sprayed on the skin under clothing. For detailed information about using repellents, see Insect Repellent Use and Safety.

·  Other options include wearing protective clothing (long sleeves, socks, and long pants) when outdoors.

·  The primary mosquito-biting hours for many of the species that are important vectors of WNV are from dusk to dawn. It is advisable to either stay indoors during these hours or use protective clothing and repellent.

·  Household mosquito-source reduction is also important. Standing water should be removed from outdoor receptacles in the periresidential environment.

·  Integrated mosquito management can be another important factor in controlling mosquito populations. (See Q & A: Pesticides Used in Mosquito Control.)

Clinical Practice

The following website is linked from the CDC webite and may contain information useful to the healthcare practitioner:

The Physicians' Information & Education Resource Guidance Statement Information on West Nile Virus Disease

Instructions for Sending Diagnostic Specimens to the DVBID Arbovirus Diagnostic Laboratory

1. CDC Submission Form

Complete a CDC submission form (CDC 50.34). Copies of this form may be obtained from: www.cdc.gov/ncidod/dvbid/misc/specimen-submission.htm.

NOTE: Testing will not be initiated without the inclusion of:

1. date of onset of symptoms
2. date of specimen collection
   NOTE: If the specimen collection occurs within 8 days after the onset of symptoms, a convalescent specimen will be requested.
3. any pertinent travel history (3 months prior to the date of symptom
   onset)
4. the patient's name (REQUIRED for submitting specimens)

2. Shipping

For information regarding shipping packages and applicable regulations, please refer to CDC's Scientific Resources Program for specific information:

http://www.cdc.gov/ncidod/srp/specimens/specimens.html

3. Specimen types and amounts

1. Acute and convalescent specimens, if available, should be sent together.
2. Ideal timing of specimens for serology:

3. At least 0.5 mL of serum and/or 1.0 mL of CSF is required for serology testing. CSF specimens are routinely tested undiluted and therefore require larger amounts. Whole blood will not be accepted for serology testing.
4. For serology testing, the specimen should be kept cold or frozen. The sample may be placed in an insulated container with blue ice packs. Additional blue ice packs should be used in the summer to ensure specimen integrity in hot weather.

e.       For virus isolation and/or nucleic acid amplification testing, acceptable specimens are fresh frozen tissue, serum, or cerebrospinal fluid. Tissue specimens should be approximately 1 cm³, frozen as soon as possible at -70ºC, and shipped on enough dry ice so that specimens remain frozen until received. Formalin-fixed specimens are not tested at DVBID and can be submitted to the Special Pathogens Laboratory in Atlanta, GA for immunohistochemistry:

Infectious Disease Pathology Activity
Centers for Disease Control and Prevention (MS-G32)
1600 Clifton Rd, NE
Atlanta, GA 30333

4. Testing Results

Test results are normally available 4 to 14 days after specimen receipt. Reporting times for test results may be longer during summer months when arbovirus activity increases. Receipt of a hard copy of the results will take at least 2 weeks after testing is completed. Initial serological testing will be performed using IgM capture ELISA and IgG ELISA. If the initial results are positive, further confirmatory testing may delay the reporting of final results. ALL RESULTS WILL BE SENT TO THE APPROPRIATE STATE HEALTH DEPARTMENT. Notify your state health department of any submissions to CDC.

5. Shipping Address

Send all specimens to:

ATTENTION: Arbovirus Diagnostic Laboratory, DRA

CDC/DVBID/ADB

3150 Rampart Road

Fort Collins, C0 80521

6. Further assistance

Additional assistance may be obtained from the DVBID Arbovirus Diagnostic and Reference Laboratory at 970-221-6445.

Fight  The Bite!
Avoid Mosquito Bites to Avoid Infection