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When specimens should be collected

Ideally specimens should be collected within 7 days of illness onset

Specimens for novel influenza A virus testing should be collected as soon as possible after illness onset, ideally within 7 days of illness onset.

In some circumstances, specimens may be collected later

The duration of shedding of novel influenza A viruses in humans is largely unknown, and there are currently limited data describing viral shedding of people infected with these viruses. Some people infected with seasonal influenza viruses can shed virus for longer periods (e.g., children and immunocompromised persons). Additionally, prolonged shedding of novel influenza A viruses in the lower respiratory tract has been documented in critically ill patients with highly pathogenic avian influenza A(H5N1) virus and avian influenza A(H7N9) virus infections. For these reasons, specimens for novel influenza A virus testing should be collected from symptomatic persons even if obtained after 7 days from illness onset.

Before collecting specimens

Clinicians and public health personnel should consider the following for surveillance and testing:

1. Consider the possibility of infection with novel influenza A viruses known to cause severe disease or with the potential to cause severe disease in humans in patients who present with acute respiratory infection (ARI) symptoms or conjunctivitis, and who have had recent direct or close contact (particularly unprotected exposure without use of respiratory protection and eye protection) <10 days prior to illness onset to animals and materials from animals potentially infected or confirmed to be infected with HPAI A(H5N1) virus. A full list of clinical criteria for novel influenza A virus testing is available.
2. If infection with a novel influenza A virus with the potential to cause severe disease in humans is suspected, respiratory specimens should be collected while following recommended infection control precautions. The state health department should be notified as soon as possible, and respiratory specimens should be sent to a public health laboratory such as at the state health department for immediate testing (see guidance below). More information is available on case definitions.
3. If infection with a novel influenza A virus with the potential to cause severe disease in humans is suspected, state health departments are encouraged to initiate a public health investigation with animal health partners and should notify ÐÇ¿ÕÓéÀÖ¹ÙÍø promptly.

For questions or concerns about possible human infection in patients with exposures to birds or other animals not listed , exposures that occur in geographic regions in the United States where HPAI A(H5) viruses have been recently identified are of most concern.

Specimens to collect

The following respiratory specimens should be collected as soon as possible after illness onset:

(i) a nasopharyngeal swab, and

(ii) a nasal swab combined with an oropharyngeal swab (e.g., two swabs collected separately and combined into one viral transport media vial).

(iii) If the person has conjunctivitis (with or without respiratory symptoms), when possible both a conjunctival swab and nasopharyngeal swab should be collected and tested separately. However, conjunctival swabs may be tested without a respiratory sample when testing with ÐÇ¿ÕÓéÀÖ¹ÙÍø's H5 assay if a paired respiratory sample is not available.

*The nasopharyngeal swab and the combined nasal-throat swabs should be tested separately.

If the above specimens cannot be collected

A single nasal swab, or oropharyngeal swab is acceptable.

For patients with severe respiratory disease

Patients with severe respiratory disease with suspected novel influenza A virus infection also should have lower respiratory tract specimens (e.g., an endotracheal aspirate or bronchoalveolar lavage (BAL) fluid from intubated patients or induced sputum) collected, if possible, because these specimens have a higher yield for detecting HPAI A(H5N1) and A(H7N9) viruses and may facilitate detection of other novel influenza A viruses. For severely ill persons, multiple respiratory tract specimens from different sites should be obtained from the same patient on at least two consecutive days for hospitalized patients to increase the potential for novel influenza A virus detection.

Materials needed

Recommended swabs

Swab specimens should be collected using swabs with a synthetic tip (e.g., polyester or Dacron®) and an aluminum or plastic shaft.

The swab specimen collection vials should contain 1-3ml of sterile viral transport medium or universal transport medium (e.g., containing protein stabilizer, antibiotics to discourage bacterial and fungal growth, and buffer solution).

Swabs that are not recommended

Swabs with cotton tips and wooden shafts are not recommended. Specimens collected with swabs made of calcium alginate are not acceptable.

Safety considerations

Standard, contact, and airborne (placement of the patient in an airborne infection isolation room, and use of fit-tested N95 respirator or higher level of respiratory protection) precautions, and use of eye protection are recommended for management of patients with suspected or laboratory-confirmed novel influenza A virus infection; this includes while collecting respiratory and conjunctival specimens. Practitioners should adhere to infection control precautions recommended for novel influenza A viruses known to cause severe disease in humans.

Shipping

Specimens should be placed into sterile viral transport media or universal transport media and immediately placed on refrigerant gel-packs or at 4°C (refrigerator) for transport to the laboratory. BAL specimens in phosphate buffered saline are acceptable.

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