| Seasonal influenza |
-
•
Incubation period 1–4 days
-
•
Increased suspicion during winter season, if current outbreak and in unvaccinated individuals
-
•
Myalgia, arthralgia, lethargy, headache, malaise
-
•
Dry cough that can last for 2 or more weeks
-
•
Sore throat, nasal congestion, rhinorrhoea
-
•
Diarrhoea, abdominal pain, nausea, vomiting more common in children
|
-
•
Fever >38°C
-
•
Mild cervical lymphadenopathy, more common in children
-
•
In children: tachypnoea, conjunctival erythema, nasal oedema, hyperaemia of oropharynx
|
-
•
Diagnosis based on signs and symptoms
-
•
Nasopharyngeal swab, particularly if high risk of complications, in high-risk groups and hospitalized patients
-
•
Rapid diagnostic test can be appropriate – around 70% sensitive and 90% specific
-
•
Chest X-ray usually normal, infiltrates suggest pneumonia
|
-
•
Seasonal influenza vaccination, especially for high-risk groups
-
•
Most recover without needing medical attention within 1 week
-
•
Antipyretics/analgesics, encourage fluids
-
•
For hospitalized patients or individuals at risk of complications or in an at-risk group, if influenza is circulating in the community, and treatment can be started within 48 hours of symptom onset (36 hours for zanamivir in children), give neuraminidase inhibitors,a and follow guidanced
,
e
-
•
Resistance to adamantanes
-
•
Post-exposure prophylaxis with neuraminidase inhibitors;a if influenza is circulating, and close contact with case, and in at-risk group and not immunized and follow guidancee
,
f
|
| A(H5N1) |
-
•
Incubation period 2–5 days, ranging to 17
-
•
Can present with mild to severe symptoms
-
•
Contact history with birds or close contact with a case
-
•
History of travelb
-
•
Dry or productive cough
-
•
Dyspnoea
-
•
Malaise and myalgia
-
•
Progress to severe lower respiratory tract disease during days 3–6 in many
-
•
Abdominal pain, diarrhoea and vomiting associated with HPAI H5N1
-
•
Can progress quickly to ARDS, multiorgan failure
-
•
Reported complications: encephalitis, altered mental state, seizures, spontaneous abortion
-
•
Sore throat and coryza less common
|
-
•
Fever >38°C
-
•
Hypoxaemia
-
•
Tachypnoea
-
•
Rales, wheezing, and focal decreased breath sounds on auscultation
-
•
Multiple organ dysfunction
-
•
Secondary bacterial and fungal infection
-
•
53% case fatality rate
|
-
•
Nasopharyngeal and throat swab or endotracheal aspirate if intubated (rapid diagnostic tests are inappropriate)
-
•
Chest X-ray can be normal or show pneumonia-like infiltrates
-
•
Blood tests: severe cases can show leukopenia, lymphopenia and mild to moderate thrombocytopenia, elevated AST/ALT
|
-
•
Isolate the patient and use PPE
-
•
If meets case definition for avian influenza, start oseltamivir immediately (before a laboratory diagnosis). Dosages for the treatment of seasonal influenza are appropriate for initiating treatment; follow guidanced
,
e
,
g
-
•
Post-exposure prophylaxis with neuraminidase inhibitors;a follow guidanceg
-
•
Corticosteroids not recommended unless adrenal insufficiency or refractory septic shock
-
•
A(H5N1) vaccines have been developed and licensed around the world, including Europe and the USA, for use in pandemic situations
|
| A(H7N9) |
-
•
Incubation period 1–10 days, average 5
-
•
Can present with mild to severe symptoms
-
•
Contact history with birds/poultry or close contact with a case
-
•
History of travelc
-
•
Dry or productive cough
-
•
Dyspnoea
-
•
Some have headache, myalgia, fatigue, diarrhoea or vomiting; sore throat less likely
-
•
Progress to severe lower respiratory tract disease during days 3–6 in many, multiorgan dysfunction/failure, ARDS
-
•
Reported complications: haemophagocytosis, shock, DIC
-
•
Atypical presentations: mental status, seizures and febrile diarrhoeal illness progressing to pneumonia
|
-
•
Fever >38°C
-
•
Hypoxaemia
-
•
Tachypnoea
-
•
Rales, wheezing, and focal decreased breath sounds on auscultation
-
•
Multiple organ dysfunction
-
•
Secondary bacterial and fungal infection
-
•
Clinical findings similar to community-acquired pneumonia
-
•
39% case fatality rate
|
-
•
Nasal, nasopharyngeal or oropharyngeal swab or endotracheal aspirate if intubated (rapid diagnostic tests are inappropriate)
-
•
Chest X-ray can be normal or show pneumonia-like infiltrates
-
•
Blood tests: can have normal white cell count or mild leukopenia, lymphopenia and mild to moderate thrombocytopenia; elevated AST/ALT
|
-
•
Isolate the patient and use PPE
-
•
If meets the case definition for avian influenza, start oseltamivir immediately (before a laboratory diagnosis). Dosages for the treatment of seasonal influenza are appropriate for initiating treatment, follow guidanced
,
e
,
g
-
•
Post-exposure prophylaxis with neuraminidase inhibitors.a Because of oseltamivir resistance seen in H7N9, use a treatment dose, follow guidanceg
-
•
Resistance shown to adamantanes
-
•
Corticosteroids not recommended unless adrenal insufficiency or refractory septic shock
-
•
Vaccines are being developed; none are licensed
|
