Dengue Virus: Reporting and Surveillance

DHS surveillance resources

• Arboviral Infection EpiNet, P-01930 (PDF): An arboviral infection case reporting and investigation protocol for health professionals.
• Arbovirus Management Protocol, P-00894 (PDF): Information for arboviral disease management, including surveillance, testing, reporting, and follow-up, in humans and animals.

Provider resources

• Dengue Virus Information for Health Care Providers: Information on clinical presentation, laboratory testing and reporting, diagnosis and laboratory guidance from the CDC (Centers for Disease Control and Prevention).
• Dengue Case Management Pocket Guide (PDF): A reference for health care providers on dengue clinical management from the CDC.

Patients with suspected acute dengue should be tested using one of the following combinations of diagnostic tests:

• Nucleic acid amplification test (NAAT) and an IgM antibody test, or
• Non-structural protein 1 (NS1) antigen test and an IgM antibody test.

During the first 7-14 days of illness, performing both NAAT (e.g., RT-PCR) or NS1 and IgM antibody tests can detect more cases than performing just one test during this time period, and usually allows diagnosis with a single sample.

Test sensitivity of RT-PCR and NS1 antigen tests decreases after the first 7 days, but some patients may be positive after day 7 of illness. IgM antibodies may not be detectable within the first 7 days of illness. IgG detection in a single serum sample should not be used to diagnose acute dengue because it does not distinguish between current and previous dengue virus infection. Often, collection of both acute and convalescent specimens may be necessary to make a serologic diagnosis of dengue infection. For further information on laboratory diagnosis of dengue infection, please visit Clinical Testing Guidance for Dengue from the CDC.

Dengue Testing at the Wisconsin State Laboratory of Hygiene

Dengue testing is available at many commercial labs. Dengue virus testing can also be requested through the Wisconsin State Laboratory of Hygiene (WSLH) using a RT-PCR panel (includes tests for dengue, Zika, and chikungunya viruses) or dengue IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA). The WSLH will automatically forward positive specimens to CDC for serotyping or serologic confirmation by plaque reduction neutralization testing (PRNT).

The Arbovirus PCR panel (test code SS02310) and dengue IgM antibody test (test code SS02272) are available at the WSLH either fee-for-service (no prior approval needed) or fee-exempt (prior approval needed). Prior approval is not required to submit specimens to WSLH for dengue testing, unless fee-exempt testing is being requested.

Providers may request fee-exempt dengue testing for patients who:

• Have symptoms consistent with dengue, and
• Traveled to an area with a risk of dengue within 14 days of illness onset, and
• Would not otherwise have access to testing for financial reasons (for example, lack insurance coverage).

Public health officials may request fee-exempt dengue testing for patients with:

• Dengue positive test results from a clinical or commercial lab (performed at laboratories other than the WSLH) for laboratory confirmation, or
• Evidence of an arboviral infection who are part of a public health investigation.

To request fee-exempt testing at WSLH, please contact a DPH vectorborne disease epidemiologist at 608-267-9003 or DHSDPHBCD@dhs.wisconsin.gov prior to specimen submission.

Instructions for collection and shipping of clinical specimens to the WSLH:

• Submit 2-5 mL of serum in sterile screw-capped vials on ice using a WSLH kit #22 or equivalent within five days of collection. If shipping more than five days after collection, freeze specimen at -20°C and ship on dry ice. Specimens should be triple packaged as a Category B Biological Substance (include UN3373 label).
• Fee-exempt testing submissions must include a WSLH Enhanced Wisconsin Arbovirus Surveillance form provided by a DPH vectorborne disease epidemiologist in addition to the WSLH Requisition Form B.
• Fee-for-service testing submissions must include a WSLH CDD Requisition Form B. Please contact the WSLH Clinical Orders at 800-862-1088 or 608-224-4275 to obtain the WSLH CDD Requisition Form B and to order specimen shipping kits.
• It is essential that the lab requisition form be as complete as possible, including patient name, city, date of birth, specimen type, submitting agency, onset date, signs and symptoms, collection date, and recent travel history. Note: Testing for dengue virus may be delayed on specimens missing the above data until information is available.
• Ship specimens with the appropriate, completed forms to:
  Wisconsin State Laboratory of Hygiene
  2601 Agriculture Drive
  PO Box 7904
  Madison, WI 53718
  Customer Service: 800-862-1013

Diagnosis of dengue can be challenging since many of the signs and symptoms can be similar to other viral infections. For example, Zika and chikungunya viruses are transmitted by the same mosquitoes as those that spread dengue virus, have overlapping geographical ranges, and have similar clinical presentations. Additionally, dengue IgM antibodies can cross-react with related viruses, such as Zika virus and West Nile virus, requiring confirmatory laboratory testing or convalescent specimen collection. A patient’s clinical signs and symptoms and risk activities can help to inform a preliminary diagnosis prior to laboratory confirmation.

Clinical presentation of a dengue infection can range from a mild, non-specific febrile illness to severe dengue hemorrhagic fever or dengue shock syndrome. Severe forms of dengue typically develop after a two to seven day febrile phase, and can involve sudden onset of plasma leakage or other hemorrhagic manifestations, or shock. Warning signs after fever subsides indicate the need for immediate medical attention. These warning signs can include mucosal bleeding, persistent vomiting, liver enlargement, increase in hematocrit with decrease in platelet count, pleural effusion or ascites. For additional information on clinical diagnosis of dengue virus infection, visit CDC's Clinical Features of Dengue.

There is currently no specific antiviral treatment for dengue. Over-the-counter pain relievers, such as Tylenol, may be given to relieve the symptoms. Patients should be advised to stay well hydrated and avoid aspirin (acetylsalicylic acid), aspirin-containing drugs, or other nonsteroidal anti-inflammatory drugs (such as ibuprofen), as they can increase the risk of bleeding.

Febrile patients should avoid mosquito bites to reduce the risk further transmission.

In severe cases, patients may need to be hospitalized to receive supportive treatment.

For more information about clinical management of dengue, visit CDC's Clinical Care of Dengue.