West Nile Epi Help

August 20, 2011

in updates

Dear Infection Control Practitioner, 

Since the 2002 outbreak of West Nile Virus in Ohio, The Cuyahoga County Board of Health (CCBH) has conducted surveillance of West Nile Virus infections in mosquito populations.  Mosquito traps are set in populated areas throughout the county to collect data regarding the presence and amount of West Nile Virus. This data is then used to guide decision making regarding mosquito adulticide spraying in affected areas. Mosquito surveillance is also important because an increase in West Nile Virus in mosquitoes forewarns us of infection in humans. Recently, there has been an increase in the amount of West Nile Virus amongst mosquitoes to the extent that human cases are very likely to occur in the near future. Thus, actions have been taken to curb the mosquito population.

The CCBH conducts passive surveillance of human WNV cases by monitoring for cases of meningitis and encephalitis through the Ohio Disease Reporting System as well as through a symptom-based surveillance of emergency room encounters. We also conduct symptom-based surveillance of emergency room encounters looking for an increase in the number of flu-like illnesses.  However, we will not be able to attribute any epidemic or pandemic activity to the West Nile Virus if cases are not clinically confirmed. Although confirmation of the infection may not affect medical decision-making for individual patients, it will aid in our understanding of the risk of infection in our community and support the CCBH to further target areas with increased risk of infection with adulticide.  Hence, we are asking providers to consider WNV testing when treating cases of aseptic meningitis or encephalitis. The most useful test to order is the IgM titer for West Nile Virus on cerebral spinal fluid. When a positive test result is seen, CCBH will be notified. In addition, confirmation of a West Nile Virus case will occur in coordination with The Ohio Department of Health and The Centers for Disease Control and Prevention. The instructions for sending samples to aid in surveillance are below.

Specimens need to be submitted with two forms:

1) The ODH Lab Sample Submission form <http://www.odh.ohio.gov/pdf/IDCM/frm2530.pdf> with “Specimen for West Nile testing at the CDC” in the comments.

2) The CDC’s DASH form <http://www.cdc.gov/ncezid/dvbd/pdf/CDC50_34.pdf>. This form needs to have at a minimum: the date of illness onset, the specimen collection date, any pertinent travel history, and the name of the patient.

Attached to this email is a Surveillance Alert on West Nile Virus for providers and a Patient Guide on West Nile Virus that includes techniques to reduce exposure to mosquitoes. We would appreciate your assistance in disseminating this material as well as information on the process by which providers order the antibody test at your institution.  The Surveillance Alert on West Nile Virus and the mosquito brochure can also be found at www.ccbh.net

Thank you in advance for your support. Please contact the Cuyahoga County Board of Health at (216) 201-2080 with any questions.

The Cuyahoga County Public Health Collaborative

Jackie Napolitano, RS
Program Manager, Epidemiology, Surveillance, and Informatics
Cuyahoga County Board of Health
5550 Venture Dr.

Parma, Ohio 44130

(216) 201-2001 ext. 1615
Fax (216) 676-1316

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