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For informational purposes only — not medical advice
How serious?
Risk of death
No
Vaccine available?
Time to symptoms
Countries affected
Active outbreaks
Risk for travelers is extremely low — transmission requires close contact with infected poultry. Avoid live poultry markets, poultry farms, and contact with bird droppings in affected regions. Eat only thoroughly cooked poultry and eggs. Report any respiratory illness after poultry exposure.
Zoonotic influenza caused by avian influenza A viruses (primarily H5N1, H7N9). High case fatality rate (~30–60% for H5N1). Acquired through direct contact with infected poultry. Pandemic potential if sustained human-to-human transmission develops.
Symptoms | Frequency | Severity | Onset |
|---|---|---|---|
| Cough | 83% | Mild | Early |
| Fever | 97% | Moderate | Early |
| Chills | 45% | Mild | Early |
| Conjunctivitis | 10% | Mild | Early |
| Diarrhea | 30% | Mild | Early |
| Headache | 45% | Mild | Early |
| Malaise | 65% | Mild | Early |
| Myalgia | 55% | Mild | Early |
| Sore throat | 26% | Mild | Early |
| Abdominal pain | 15% | Mild | Early |
| Loss of appetite | 35% | Mild | Early |
| Nausea | 18% | Mild | Early |
| Vomiting | 20% | Mild | Early |
| Rhinorrhea | 15% | Mild | Early |
| Shortness of breath | 72% | Severe | Peak |
| Chest tightness | 40% | Moderate | Peak |
| Productive cough | 42% | Moderate | Peak |
| Hemoptysis | 10% | Severe | Peak |
| Tachycardia | 40% | Moderate | Peak |
| Altered consciousness | 8% | Critical | Late |
Avian influenza (commonly called "bird flu") refers to disease caused by infection with influenza type A viruses that are adapted to birds but can occasionally infect humans and other mammals. Multiple subtypes have caused zoonotic infections in humans, most notably H5N1, H7N9, H5N6, and H9N2, each with distinct epidemiological profiles and clinical severity.
Avian influenza viruses circulate widely among wild aquatic birds (the natural reservoir) and can spread to domestic poultry, where highly pathogenic strains cause devastating outbreaks. Human infections occur sporadically through direct or close contact with infected poultry or contaminated environments, particularly in live poultry markets. There is currently no sustained human-to-human transmission, but limited person-to-person spread has been documented in rare clusters.
Since the first recognized human cases of H5N1 in Hong Kong in 1997, the WHO has documented over 880 confirmed H5N1 cases with more than 460 deaths (case fatality rate ~53%). H7N9, first identified in China in 2013, has caused approximately 1,500 confirmed cases with a CFR of ~40%. Avian influenza viruses are of critical concern to global public health because of their pandemic potential — the possibility that a highly pathogenic avian virus could acquire the ability to spread efficiently between humans, potentially causing a devastating pandemic.
Avian influenza encompasses a group of influenza A viruses with zoonotic potential, characterized by their hemagglutinin (H) and neuraminidase (N) surface proteins.
Key facts:
Causative agents: Influenza A viruses — 18 hemagglutinin (H1–H18) and 11 neuraminidase (N1–N11) subtypes; subtypes with documented human infections include H5N1, H7N9, H5N6, H9N2, H7N7, H7N2, H7N3, H10N8, and H6N1
Natural reservoir: Wild aquatic birds (waterfowl, shorebirds) carry low-pathogenic avian influenza (LPAI) asymptomatically
Pathogenicity classification:
Incubation period: H5N1: typically 2–8 days (up to 17 days); H7N9: 1–10 days
Transmission to humans: Direct contact with infected poultry (live or dead), contaminated environments (live bird markets, poultry farms), or rarely through contaminated water; no evidence of transmission through properly cooked poultry or eggs
Major zoonotic subtypes:
Subtype First human case Total human cases CFR Geographic focus H5N1 1997 (Hong Kong) >880 ~53% Egypt, Indonesia, Vietnam, Cambodia H7N9 2013 (China) ~1,500 ~40% China H5N6 2014 (China) ~80+ ~30–40% China H9N2 1998 ~100+ <5% China, Egypt, BangladeshAvian influenza is classified as a WHO-monitored disease with pandemic preparedness implications under the International Health Regulations (IHR 2005).
Seek emergency medical attention immediately if you develop the following symptoms within 10 days of contact with poultry or birds in an area with known avian influenza outbreaks:
Critical warning signs:
High fever (>38°C) with cough and progressive dyspnea — especially if worsening over 24–48 hours; lower respiratory involvement in avian influenza progresses rapidly
Difficulty breathing or shortness of breath at rest — suggests developing ARDS; this can deteriorate within hours
Cyanosis — bluish discoloration of lips, fingertips, or skin indicating hypoxemia
Chest pain — pleuritic or persistent, suggesting pneumonia or myocarditis
Altered mental status — confusion, drowsiness, or disorientation may indicate encephalitis or severe hypoxemia
Persistent vomiting and inability to maintain hydration
Bloody or purulent sputum
When to suspect avian influenza specifically:
Critical actions:
Most common signs and symptoms
The clinical spectrum of avian influenza in humans ranges from asymptomatic infection and mild conjunctivitis to fulminant viral pneumonia and death. Severity depends heavily on the infecting subtype.
H5N1 (most severe):
Onset: Abrupt, with high fever (>38°C), severe myalgia, headache, and malaise
Lower respiratory tract involvement occurs early — productive cough, dyspnea, and pleuritic chest pain develop within 1–5 days of symptom onset
Rapid progression to bilateral pneumonia, often with diffuse ground-glass infiltrates on chest imaging
Acute respiratory distress syndrome (ARDS) develops in the majority of hospitalized patients, typically by days 3–7
Gastrointestinal symptoms are common — watery diarrhea, vomiting, and abdominal pain may precede respiratory symptoms in up to 70% of cases
Multi-organ dysfunction — renal failure, hepatic impairment, and cardiac dysfunction
Encephalitis — rare but reported in children
Lymphopenia is a hallmark laboratory finding and predictor of severity
Median time from symptom onset to death: 9–10 days in fatal cases
H7N9:
Similar presentation to severe seasonal influenza initially — fever, cough, dyspnea
Rapid progression to pneumonia and ARDS in most hospitalized cases
Older patients (median age 58 years) and those with comorbidities are disproportionately affected
Less gastrointestinal involvement compared to H5N1
H9N2 and other low-pathogenicity subtypes:
Typically cause mild upper respiratory illness — fever, cough, sore throat
Conjunctivitis — particularly reported with H7 subtypes (e.g., H7N7 outbreak in the Netherlands, 2003)
Most cases are self-limited
Notable features distinguishing avian influenza from seasonal influenza:
More prominent lower respiratory tract involvement from onset
Diarrhea as an early symptom (uncommon in seasonal influenza)
Rapid clinical deterioration despite antiviral therapy
Lymphopenia (rather than leukocytosis)
Knowing the symptoms is the first step to a quick response.
The clinical course of avian influenza in humans, particularly H5N1 and H7N9, typically follows a rapid and aggressive trajectory distinct from seasonal influenza.
Exposure and incubation:
Virus exposure through inhalation of aerosolized virus particles, direct contact with infected poultry or contaminated surfaces, or possibly ingestion
Incubation period: H5N1: 2–8 days (up to 17 days reported); H7N9: 1–10 days (median 5 days)
During incubation, the virus replicates primarily in the respiratory epithelium
Days 1–3 (symptom onset):
Abrupt onset of high fever (often >39°C), myalgia, headache, and malaise
Cough is initially non-productive
Gastrointestinal symptoms (diarrhea, vomiting, abdominal pain) develop early in ~70% of H5N1 cases — a distinguishing feature from seasonal influenza
Upper respiratory symptoms (rhinorrhea, sore throat) are less prominent than in seasonal influenza
Days 3–7 (rapid progression):
Progressive dyspnea develops as viral pneumonia establishes in the lower respiratory tract
Chest imaging shows bilateral pulmonary infiltrates with rapid progression
ARDS develops in the majority of hospitalized H5N1/H7N9 cases, typically between days 3–7
Lymphopenia deepens; inflammatory markers (CRP, ferritin, LDH) rise sharply
Cytokine storm — excessive immune activation with elevated IL-6, TNF-alpha, and IP-10; a major driver of lung injury and multi-organ dysfunction
Days 7–14 (critical phase):
Patients requiring mechanical ventilation face the highest mortality risk during this window
Multi-organ dysfunction may develop: acute kidney injury, hepatic impairment, rhabdomyolysis, disseminated intravascular coagulation (DIC)
Secondary bacterial pneumonia may complicate the course
Cardiac involvement — myocarditis, pericarditis reported in some cases
Outcome:
Fatal cases: Median time from onset to death is 9–10 days for H5N1 (range 4–30 days); death typically results from refractory hypoxemia, multi-organ failure, or septic shock from secondary infection
Survivors: Recovery from ARDS is prolonged; median ICU stay 2–3 weeks; full pulmonary recovery may take months
Mild cases (H9N2, some H7N9): Self-limited illness resolving in 5–7 days without hospitalization
How this disease is identified
Diagnosis of avian influenza requires a high index of clinical suspicion based on exposure history, combined with specialized laboratory testing. Standard rapid influenza tests are insufficient for ruling out avian influenza.
Case definition (WHO): A person with acute respiratory illness (fever ≥38°C and cough) with onset within 10 days of:
Direct contact with infected or suspected infected poultry (live or dead) or their environments
Close contact with a confirmed or probable avian influenza case
Working in a laboratory handling avian influenza specimens
Living in or traveling to an area with active avian influenza outbreaks in poultry or humans
Laboratory diagnosis:
RT-PCR (reverse transcription polymerase chain reaction) — the gold standard for confirmation
Virus culture — provides definitive identification and allows antigenic characterization; must be performed in BSL-3 or higher containment facilities; takes 2–7 days
Rapid influenza diagnostic tests (RIDTs): May detect influenza A but cannot differentiate subtypes and have poor sensitivity (~30–50%) for avian influenza; a negative RIDT does NOT rule out avian influenza
Immunofluorescence assay (DFA/IFA): Can detect influenza A but cannot distinguish avian subtypes; moderate sensitivity
Serology: Microneutralization assay and hemagglutination inhibition (HI) using avian influenza antigens; requires paired sera (acute + convalescent, 14–21 days apart); useful for retrospective diagnosis and seroprevalence studies; must be performed in BSL-3
Imaging:
Chest X-ray: Bilateral diffuse infiltrates, ground-glass opacities, consolidation — often multilobar from early in the course
CT chest: Bilateral ground-glass opacities with or without consolidation; rapid progression is characteristic
Important notes:
All specimens from suspected avian influenza cases must be handled with enhanced biosafety precautions (BSL-3 for culture)
WHO reference laboratories should be notified for novel subtype confirmation
Testing should be coordinated with national influenza centers or WHO Collaborating Centres
Available treatment methods
Treatment of avian influenza in humans centers on early antiviral therapy and aggressive supportive care, particularly respiratory support.
Antiviral therapy:
Oseltamivir (Tamiflu) — neuraminidase inhibitor; WHO-recommended first-line treatment
Zanamivir — inhaled neuraminidase inhibitor; alternative to oseltamivir; IV formulation available for critically ill patients unable to take oral medication
Peramivir — IV neuraminidase inhibitor; useful when oral and inhaled routes are not feasible
Baloxavir marboxil — cap-dependent endonuclease inhibitor; active against avian influenza viruses in vitro; may be used in combination with oseltamivir for severe cases (WHO conditional recommendation)
Resistance: Most H5N1 and H7N9 strains remain susceptible to neuraminidase inhibitors, but oseltamivir resistance (H275Y mutation) has been documented; zanamivir generally retains activity against oseltamivir-resistant strains
Supportive care:
Oxygen therapy — early and aggressive supplemental oxygen; target SpO₂ >92%
Mechanical ventilation — required in the majority of severe H5N1 and H7N9 cases; lung-protective ventilation strategies (low tidal volume, PEEP) per ARDS guidelines
Prone positioning — improves oxygenation in ARDS
ECMO (extracorporeal membrane oxygenation) — considered for refractory hypoxemia; limited availability
Fluid management — conservative fluid strategy to avoid pulmonary edema
Corticosteroids — not routinely recommended; may worsen viral replication; used only for refractory shock or specific indications
Antibiotic therapy for secondary bacterial pneumonia, which is common in severe cases
Investigational therapies:
Convalescent plasma and hyperimmune globulin have shown mixed results
Monoclonal antibodies targeting the hemagglutinin stalk are in clinical development
Most cases are effectively treated with early diagnosis.
How to protect yourself
Prevention of human avian influenza focuses on reducing exposure to infected poultry, poultry industry biosecurity, and pandemic preparedness. No widely available vaccine exists for avian influenza subtypes, though candidate vaccines have been developed and stockpiled.
Personal protective measures for travelers and the public:
Avoid live poultry markets (wet markets) in countries with reported avian influenza outbreaks — this is the most effective individual measure; live bird markets are the primary interface for zoonotic transmission
Avoid contact with sick or dead poultry and wild birds — do not handle or approach birds that appear ill, dying, or recently dead
Do not visit poultry farms during outbreaks unless essential and with appropriate personal protective equipment (PPE)
Practice hand hygiene — wash hands thoroughly with soap and water after any contact with birds, poultry environments, or raw poultry products
Food safety: Poultry meat and eggs are safe to eat when thoroughly cooked (internal temperature >70°C/158°F); avian influenza viruses are killed by heat; avoid raw or undercooked poultry and eggs in affected areas
Seasonal influenza vaccination does not protect against avian influenza but is recommended to reduce the risk of co-infection and potential reassortment
Occupational protection (poultry workers, cullers, veterinarians):
Full PPE during contact with potentially infected poultry: N95/FFP2 respirator, goggles or face shield, disposable gown, gloves, boots
Seasonal influenza vaccination — recommended to reduce reassortment risk
Antiviral prophylaxis — oseltamivir 75 mg daily may be offered during high-risk exposure activities
Poultry industry biosecurity (public health level):
Rapid detection and reporting of HPAI outbreaks in poultry
Stamping out (culling) of infected flocks — the primary control measure
Poultry vaccination (H5, H7) — used in some countries (China, Egypt, Indonesia) to reduce viral circulation in poultry
Separation of domestic poultry from wild birds; biosecurity standards on commercial farms
Closure of live bird markets during outbreaks
Pandemic preparedness:
WHO coordinates a global pandemic influenza preparedness framework (PIP Framework)
Pre-pandemic H5N1 vaccines have been developed and are stockpiled by several countries and WHO
Pandemic vaccine production capacity: estimated 4.2 billion doses within 6 months of pandemic declaration using mRNA, cell-based, and egg-based platforms
Surveillance of avian influenza viruses in animals and humans is critical for early detection of mutations enhancing human transmissibility
Preparation is the best protection.
Risk assessment for travelers: The risk of avian influenza for most travelers is very low. Human infections are sporadic and almost exclusively linked to direct contact with infected poultry or contaminated environments. Standard tourist activities, including consuming properly cooked poultry, pose negligible risk.
Situations that increase risk:
Visiting live poultry markets (wet markets) in countries with active HPAI outbreaks — the single most important risk factor for travelers
Visiting or working on poultry farms during outbreaks
Handling sick or dead birds (domestic or wild)
Rural travel in areas with ongoing poultry outbreaks where backyard poultry keeping is common
Regions with historical or ongoing avian influenza activity in poultry and/or humans:
H5N1: Egypt, Indonesia, Vietnam, Cambodia, China, Bangladesh, Myanmar, parts of West Africa (Nigeria), and increasingly global HPAI outbreaks in poultry/wild birds (2021–present: Europe, Americas, Africa)
H7N9: China (primarily eastern provinces; no human cases since 2019 following mass poultry vaccination)
H5N6: China (sporadic human cases)
H5N1 clade 2.3.4.4b (2021–present): Unprecedented global spread in wild birds and poultry across Europe, Americas, Africa, and Asia; sporadic human cases including in previously unaffected countries
Traveler precautions:
Avoid live poultry markets — do not enter areas where live birds are sold, slaughtered, or de-feathered
Do not touch or feed poultry, pigeons, or wild birds
Eat only thoroughly cooked poultry and eggs — properly cooked food is safe
Wash hands frequently — especially before eating and after visiting markets or rural areas
Carry alcohol-based hand sanitizer
Report any illness with fever and respiratory symptoms developing within 10 days of poultry exposure to a healthcare provider, and disclose your travel and exposure history
Post-travel:
If you develop fever with respiratory symptoms within 10 days of contact with poultry or live bird markets, seek medical attention immediately and inform the clinician of your exposure history
The WHO does not recommend travel restrictions to countries with avian influenza outbreaks in poultry
Statistics and geographic data
Avian influenza has a complex epidemiology spanning animal and human health, with sporadic zoonotic infections occurring against a background of massive global poultry and wild bird outbreaks.
H5N1 (since 1997):
First human cases: Hong Kong, 1997 (18 cases, 6 deaths); re-emerged in 2003 in Southeast Asia
Cumulative total (WHO, 2024): >880 confirmed human cases in 23 countries, with >460 deaths (CFR ~53%)
Countries with most human cases: Egypt (~360 cases), Indonesia (~200 cases), Vietnam (~130 cases), Cambodia (~60 cases), China (~50 cases)
Since 2020: H5N1 clade 2.3.4.4b has caused unprecedented panzootic in wild birds and poultry across all continents except Oceania; massive die-offs in seabirds, marine mammals; sporadic human cases in poultry workers and dairy farm workers (USA, 2024)
H7N9 (since 2013):
First identified: Eastern China, March 2013
Five epidemic waves (2013–2017), with the fifth wave being the largest
Cumulative total: ~1,568 confirmed human cases, ~616 deaths (CFR ~39%)
Virtually all cases from China (>99%); rare exported cases in travelers
Near-zero human cases since 2019 following implementation of mass H7N9 vaccination in Chinese poultry
Other subtypes:
H5N6: ~80+ human cases (2014–present), primarily China; CFR ~30–40%
H9N2: ~100+ human cases; predominantly mild; widespread in poultry across Asia, Middle East, Africa; significant because it contributes internal gene segments to other avian influenza reassortants
H7N7: Netherlands, 2003 — 89 human cases (1 death); mostly conjunctivitis
H10N8, H6N1: Isolated human cases in China
Current global situation (2024–2026):
H5N1 clade 2.3.4.4b panzootic continues with unprecedented geographic spread
New host species affected: dairy cattle (USA, 2024), foxes, seals, sea lions
Enhanced surveillance globally; WHO maintains risk assessment as "low" for general population but "low-to-moderate" for occupationally exposed individuals
Pandemic preparedness planning intensified; mRNA and cell-based vaccine candidates targeting clade 2.3.4.4b are in clinical trials
Pandemic risk assessment:
Current avian influenza viruses lack efficient human-to-human transmissibility
Key mutations in the hemagglutinin receptor binding site (e.g., PB2 E627K, HA Q226L) that could increase mammalian adaptation are under continuous monitoring
The 1918, 1957, and 1968 influenza pandemics all involved avian-origin gene segments
Who is most at risk
Risk factors for avian influenza in humans relate primarily to exposure intensity and host susceptibility.
Exposure-related risk factors (most important):
Direct contact with infected poultry — handling, slaughtering, de-feathering, or butchering infected birds is the highest-risk activity; studies show a dose-response relationship between exposure intensity and infection risk
Visiting live bird/poultry markets — the primary site of zoonotic transmission in Asia; environmental contamination with virus is common on surfaces, in water, and in air
Poultry farm workers — commercial and backyard poultry farmers in outbreak areas
Cullers and outbreak responders — personnel involved in poultry depopulation (stamping out) during HPAI outbreaks
Backyard poultry keeping — common in rural Asia, Africa, and the Middle East; close human-bird contact with minimal biosecurity
Veterinarians and laboratory workers handling avian influenza specimens
Household contact with infected poultry — keeping poultry in or near living quarters
Host risk factors for severe disease:
Age distribution:
Underlying medical conditions — chronic pulmonary disease, cardiovascular disease, diabetes mellitus, obesity, and chronic kidney disease increase severity
Immunosuppression — HIV/AIDS, organ transplant recipients, and patients on immunosuppressive therapy
Pregnancy — associated with increased severity (as with seasonal and pandemic influenza)
Delayed antiviral treatment — the most important modifiable risk factor for poor outcome; treatment >48 hours after onset significantly increases mortality
Male sex — slight male predominance in H7N9 cases, possibly reflecting occupational exposure patterns
Environmental and behavioral factors:
Live poultry market frequency — markets that hold birds overnight and have poor sanitation have higher environmental contamination
Rural versus urban — backyard poultry keeping in rural areas creates sustained close contact
Season — H7N9 cases peak in winter/spring in China, coinciding with increased live poultry trade and influenza seasonality
Potential complications
Avian influenza, particularly H5N1 and H7N9, can produce severe and rapidly progressive complications that distinguish it from seasonal influenza.
Pulmonary complications (most prominent):
Viral pneumonia — bilateral, rapidly progressive; the primary manifestation of severe disease; develops within 3–7 days of symptom onset; chest imaging shows multilobar consolidation and ground-glass opacities
Acute Respiratory Distress Syndrome (ARDS) — develops in >60% of hospitalized H5N1 patients and ~50% of hospitalized H7N9 patients; median onset day 3–7; associated with very high mortality (>60% once mechanical ventilation is required)
Pneumothorax and pneumomediastinum — may complicate mechanical ventilation in ARDS patients
Secondary bacterial pneumonia — Staphylococcus aureus, Streptococcus pneumoniae, and gram-negative bacteria are common superinfecting pathogens; contributes to late mortality
Pulmonary fibrosis — may develop as a long-term sequela of ARDS; can cause permanent reduction in lung function in survivors
Extrapulmonary complications:
Cytokine storm (hyperinflammatory response) — a hallmark of severe H5N1 infection; markedly elevated IL-6, IL-8, IL-10, TNF-alpha, IP-10, MCP-1, and MIG in serum; drives multi-organ injury; similar mechanism to severe COVID-19 and sepsis
Acute kidney injury — develops in 25–40% of critically ill patients; multifactorial (hypotension, cytokine-mediated injury, rhabdomyolysis)
Hepatic dysfunction — elevated transaminases are common; fulminant hepatic failure is rare but reported
Rhabdomyolysis — myoglobinuria contributing to renal injury
Disseminated intravascular coagulation (DIC) — coagulopathy with prolonged PT/INR, thrombocytopenia, and elevated D-dimer
Cardiac complications — myocarditis, pericarditis, and electrocardiographic abnormalities; cardiac dysfunction contributes to hemodynamic instability
Encephalitis/encephalopathy — reported primarily in children with H5N1; seizures, altered consciousness; the virus has been detected in brain tissue at autopsy
Hematologic complications:
Lymphopenia — reduction in CD4+ and CD8+ T cells; a hallmark of severe disease and an independent predictor of mortality
Hemophagocytic lymphohistiocytosis (HLH) — reactive hemophagocytic syndrome has been documented in fatal H5N1 cases; characterized by cytopenias, hyperferritinemia, and activated macrophages engulfing blood cells
Long-term sequelae in survivors:
Prolonged pulmonary impairment and reduced exercise capacity
Post-ICU syndrome — physical, cognitive, and psychological effects of prolonged critical illness
Neuropsychiatric sequelae in rare cases of CNS involvement
Expected outcomes and recovery
The prognosis of avian influenza in humans varies dramatically by subtype, ranging from nearly universal recovery (H9N2) to majority fatality (H5N1).
Case fatality rates by subtype:
H5N1: ~53% overall CFR among confirmed cases (>460 deaths out of >880 cases); likely overestimated due to surveillance bias (mild cases are underdiagnosed)
H7N9: ~40% overall CFR among hospitalized cases; ~1.4% estimated when including seropositive (mild/asymptomatic) cases from serosurveys
H5N6: ~30–40% among reported cases
H9N2: <5% CFR; most infections are mild
Prognostic factors for poor outcome in H5N1/H7N9:
Delay in antiviral treatment — the most modifiable risk factor; starting oseltamivir >48 hours after symptom onset is associated with significantly higher mortality
Age: Children >5 years and young adults have historically been most affected by H5N1 (unusual age distribution); for H7N9, older adults (>60) have the worst outcomes
Comorbidities — chronic lung disease, cardiovascular disease, diabetes, obesity, and immunosuppression worsen prognosis
Lymphopenia at presentation — a strong independent predictor of mortality
Progression to ARDS — once mechanical ventilation is required, mortality exceeds 60–70%
Multi-organ dysfunction — renal failure, hepatic dysfunction, and coagulopathy indicate poor prognosis
Viral load — higher initial viral RNA levels in blood and respiratory specimens correlate with mortality
Recovery:
Survivors of severe disease often experience prolonged ICU stays (median 2–3 weeks) and require extended rehabilitation
Pulmonary fibrosis may develop as a sequela of ARDS
Neuropsychiatric sequelae have been reported after H5N1 encephalitis
Patients with mild avian influenza infections (typically H9N2) recover fully within 1–2 weeks
The content on this page is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment recommendations. If you have health concerns, consult a qualified healthcare professional. Medova is not a medical service provider.
Full terms of useGeographic distribution and active outbreaks
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| Flag | Country | Risk level |
|---|---|---|
 | China | High risk |
 | Bangladesh | High risk |
 | Thailand | High risk |
 | Vietnam |
| High risk |
 | Egypt | High risk |
 | Cambodia | High risk |
 | United States | High risk |
 | India | High risk |
 | Indonesia | High risk |
 | Laos | High risk |