Influenza A and B viruses are responsible for respiratory epidemics each year. Influenza A Viruses are categorized by their surface proteins: Hemagglutinin (H) and Neuraminidase (N). Since Influenza B viruses are structurally different, they are only broken down into two lineages: B/Yamagata and B/Victoria (CDC, 2017).

The Delaware Public Health Lab performs influenza identification, molecular detection, and subtyping. Influenza surveillance is performed as part of the CDC-World Health Organization (WHO) Influenza surveillance effort. This information, along with a select number of isolates, is provided to CDC and the WHO to aid in surveillance efforts and future vaccine formulation.

What We Do

• Real-Time Reverse Transcriptase Polymerase Chain Reaction (rRT-PCR)
• Influenza SARS-CoV-2 (Flu SC2) Multiplex rRT-PCR
• Influenza A subtyping by rRT-PCR
• Influenza B genotyping
• Seasonal H3N2 detection  
• 2009/H1N1 Pandemic detection
• H5N1 Avian (presumptive result)
• H3N2 variant (presumptive result)
• H7N9 (presumptive result)
• Pyrosequencing – for anti-viral resistance on a subset of A/H3N2 and pandemic A/H1N1 influenza specimens
• Respiratory Virus Panel (RVP) – For outbreaks, fatalities, or specimens (with prior approval from the Office of Infectious Disease Epidemiology

Acceptable Specimens

• Nasopharyngeal washes, nasopharyngeal aspirates, nasopharyngeal swabs
• nasal or throat swabs, dual throat/nasal swabs
• bronchial washes, bronchoalveolar lavage
• lung tissue (this includes lung biopsy, bronchial biopsy, and postmortem lung specimens)
• sputum
• viral culture isolates
• Collection Kit here: Herpes\Viral\Flu\Pertussis Collection kit-Instructions

Submitting a Specimen

• Obtain collection kits from the DPHL. This kit will contain a tube with viral transport media and two dry NP swabs, and the Request for Clinical Testing form.
• Fill out the form completely.
• Label the specimen with name of patient and date of birth (or barcode, if applicable).
• Arrange for specimen transport to the laboratory.

DPH Flu Immunization Information

Delaware Weekly Influenza Surveillance Reports

CDC Flu Page

CDC Guidelines for Clinicians on the Use of Rapid Influenza Diagnostic Tests

References: Centers for Disease Control and Prevention, 2017. Types of Influenza Viruses.

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This page was last updated 4/2024

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