Clinical Guidance for Evaluating Patients and Treatment and Post-exposure Prophylaxis (PEP) of Influenza A(H5N1) Virus Infection

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Key points

  • Clinicians should consider the possibility of highly pathogenic avian influenza (HPAI) A(H5N1) virus infection in patients showing signs or symptoms of acute respiratory illness or conjunctivitis, and who have relevant exposure history.
  • Patients with relevant exposure histories who also develop signs and symptoms consistent with HPAI A(H5N1) virus infection, including acute respiratory illness or conjunctivitis, should be referred for prompt medical evaluation, testing, and empiric initiation of antiviral treatment with oseltamivir (standard dose is twice daily x 5 days) as soon as possible.
  • Antiviral post-exposure prophylaxis (PEP) with oseltamivir can be considered as soon as possible for any asymptomatic person meeting epidemiologic exposure criteria (e.g., household contacts of cases or other persons with high-risk exposures).

Overview of recommendations

Clinicians should consider the possibility of HPAI A(H5N1) virus infection in patients showing signs or symptoms of acute respiratory illness or conjunctivitis who also have relevant exposure history. This includes patients who:

  • Have had unprotected contact (without using recommended respiratory and eye protection) with potentially infected sick or dead birds, livestock, or other animals, or with secretions or other materials like animal bedding that were contaminated or potentially contaminated, within 10 days before symptom onset (e.g., handling, milking, feeding, and providing care for, as well as slaughtering, defeathering, butchering, culling, preparing for consumption or consuming uncooked or undercooked food or related uncooked food products, including unpasteurized (raw) milk or other unpasteurized dairy products) outdoors or indoors, including in a confined space.
  • Had direct contact with water or surfaces contaminated with feces, unpasteurized (raw) milk or unpasteurized dairy products, or parts (carcasses, internal organs, etc.) of potentially infected animals.

For patients who meet the above criteria, clinicians should:

  • Contact the state public health department to arrange testing for influenza A(H5N1) virus.
  • Collect respiratory specimens (visit recommendations below) utilizing recommended personal protective equipment (PPE).
  • Start empiric antiviral treatment with oseltamivir (more information below).
  • Encourage the patient to isolate at home away from their household members and not go to work or school until it is determined they do not have HPAI A(H5N1) virus infection.

Testing for other potential causes of acute respiratory illness should also be considered depending upon the local activity of circulating respiratory pathogens, including SARS-CoV-2.

Keep Reading Clinician Brief: Evaluating and Managing Patients Exposed to Animals or Persons Infected with Novel Influenza A Viruses of Public Health Concern

Infection prevention and control

Standard, contact, and airborne precautions with eye protection (e.g. goggles or face shield) are recommended for patients presenting for medical care or evaluation who have illness consistent with influenza and recent exposure to birds or other animals potentially infected with HPAI A(H5N1) virus.

Keep Reading Interim Guidance for Infection Control Within Healthcare Settings When Caring for Confirmed Cases, Probable Cases, and Cases Under Investigation for Infection with Novel Influenza A Viruses Associated with Severe Disease

Antiviral Treatment

Specific dosage recommendations for treatment by age group are available at Influenza Antiviral Medications: Summary for Clinicians. Physicians should consult the manufacturer's package insert for dosing, limitations of populations studied, contraindications, and adverse effects.

Outpatients

Outpatients meeting epidemiologic exposure criteria who develop signs and symptoms consistent with HPAI A(H5N1) virus infection, including acute respiratory illness or conjunctivitis, should be referred for prompt medical evaluation, testing, and empiric treatment with oseltamivir (twice daily x 5 days) as soon as possible. Clinical benefit is greatest when antiviral treatment is administered early, especially within 48 hours of illness onset. Empiric antiviral treatment can be started before test results are available and after 48 hours of symptom onset.

Asymptomatic persons with bird or other animal exposures who test positive for influenza A(H5N1) virus should be offered oseltamivir treatment (twice daily x 5 days), unless already receiving oseltamivir post-exposure prophylaxis (see details below).

Hospitalized patients

Hospitalized patients meeting epidemiologic exposure criteria with signs and symptoms consistent with HPAI A(H5N1) virus infection, including acute respiratory illness or conjunctivitis, regardless of time since illness onset, are recommended to initiate antiviral treatment with oral or enterically administered oseltamivir (twice daily x 5 days) as soon as possible. Antiviral treatment should not be delayed while waiting for influenza testing results. Clinicians should consult a hospital pharmacist regarding adjustment of antiviral dosing for patients with acute kidney injury or kidney failure.

Detailed guidance on dosing and treatment duration, including consideration of combination antiviral treatment, is available at Interim Guidance of the Use of Antiviral Medications for the Treatment of Human Infection with Novel Influenza A Viruses Associated with Severe Human Disease. The optimal duration and dosing of antiviral treatment are uncertain for severe or complicated influenza. Treatment regimens might need to be altered to fit the clinical circumstances. Longer duration of treatment e.g., 10 days) should be considered for severely ill hospitalized patients with influenza A(H5N1) virus infection. Combination antiviral treatment (e.g., oseltamivir and baloxavir) can be considered for hospitalized patients. Any questions regarding arranging testing for antiviral resistance, combination antiviral treatment dosing, or regarding appropriate clinical management if antiviral resistance is a concern, should be directed to the CDC Influenza Division for consultation with a medical officer via the CDC Emergency Operations Center (770-488-7100).

Asymptomatic persons with bird or other animal exposures who test positive for influenza A(H5) virus

Asymptomatic persons exposed to animals known or suspected to be infected with HPAI A(H5N1) virus who reported not wearing recommended PPE or who experienced a PPE breach in recommended PPE and who tested positive for influenza A(H5) virus should be offered oseltamivir treatment (standard dose is twice daily x 5 days) (unless already receiving oseltamivir post-exposure prophylaxis).

  • Exposed asymptomatic persons who test positive for influenza A(H5) virus should wear a facemask when in close contact with others and should continue to be actively monitored for signs and symptoms of acute respiratory illness or conjunctivitis for 10 days after testing A(H5) virus positive.
  • Any exposed person who tested positive for influenza A(H5) virus while asymptomatic and who develops signs or symptoms of acute respiratory illness or conjunctivitis while receiving oseltamivir for treatment or post-exposure prophylaxis, should be isolated, and tested again for A(H5) virus. If testing is negative for influenza A(H5) virus, testing for other respiratory pathogens can be considered.
  • Repeat testing is recommended to rule out initial A(H5) virus test positivity as a result of viral contamination, such as from an environmental exposure, that did not progress to infection [i.e., repeat testing yields a negative A(H5) virus result] and to allow for evaluation of development of antiviral resistance during treatment/prophylaxis if repeat testing is still positive for A(H5) virus.

Monitoring and Antiviral Post-exposure Prophylaxis of Close Contacts of Persons with HPAI A(H5N1) virus infection

Recommendations for monitoring and antiviral PEP of close contacts of infected people (e.g., household contacts of a case patient, healthcare personnel with unprotected exposures to a case patient) are different from those that apply to people who meet bird or other animal exposure criteria. Post-exposure prophylaxis of close contacts of a person with HPAI A(H5N1) virus infection is recommended as soon as possible with oseltamivir twice daily (treatment dosing) for 5 days as soon as possible instead of the once daily oseltamivir PEP dosing for seasonal influenza. Detailed guidance is available at Interim Guidance on Follow-up of Close Contacts of Persons Infected with Novel Influenza A Viruses and Use of Antiviral Medications for Chemoprophylaxis.

Antiviral Post-exposure Prophylaxis (PEP) of Persons with Animal Exposures

Considerations for Antiviral PEP of asymptomatic persons with exposures to animals infected with HPAI A(H5N1) virus

For people who properly used recommended PPE

Antiviral PEP is not routinely recommended for asymptomatic persons who properly used (including when taking off) recommended PPE and experienced no breaches while handling sick or potentially infected birds or other sick or dead animals or decontaminating infected environments (including animal disposal).

For people who meet the epidemiologic exposure criteria

Antiviral PEP with oseltamivir can be considered for any person meeting epidemiologic exposure criteria. Decisions to initiate antiviral PEP should be based on clinical judgment, with consideration given to the person's underlying health (e.g., pregnancy, chronic medical conditions), the type of exposure, duration of exposure, time since exposure, and known infection status of the birds or animals the person was exposed to.

Antiviral PEP is not an alternative for use of appropriate PPE and engineering and administrative controls, and receipt of PEP should not be contingent upon acceptance of and participation in influenza testing.

When feasible, offer oral oseltamivir for post-exposure prophylaxis (PEP) and avian influenza A(H5) virus testing as soon as possible to asymptomatic individuals who experienced high risk of exposure to A(H5N1) virus.

Antiviral Post-exposure Prophylaxis Dosing

If oseltamivir PEP is initiated for A(H5N1), oseltamivir treatment dosing (one dose twice daily) is recommended instead of antiviral post-exposure prophylaxis dosing (once daily) for seasonal influenza. If exposure was time-limited and not ongoing, five days of medication (one dose twice daily) from the last known exposure is recommended.

Oseltamivir PEP [twice daily x 5 days (treatment dosing)] can be given to asymptomatic persons who experienced high risk of exposure (without using recommend PPE) to animals confirmed to be infected or highly suspected to be infected with HPAI A(H5N1) virus.

Longer duration of oseltamivir PEP (e.g., twice daily for 10 days) can be given for ongoing high risk of exposure (e.g., inadequate PPE) to animals confirmed to be infected or highly suspected to be infected with HPAI A(H5N1) virus.

Vaccination

No human vaccines for prevention of influenza A(H5N1) virus infection are currently commercially available in the United States. Seasonal influenza vaccines do not provide specific protection against human infection with HPAI A(H5N1) viruses.

Interim Risk Categories by Exposure

Categories of individual risk for influenza A(H5N1) virus infection by setting and exposure, including exposure to infected poultry or dairy cows, contaminated animal products, and other suspected infected peri-domestic animals.

Last updated: November 7, 2024

This tableA provides a framework for epidemiologic assessment of individual risk for highly pathogenic avian influenza (HPAI) A(H5N1) virus infection amidst the ongoing U.S. outbreak of HPAI A(H5N1) viruses in poultry and dairy cows. CDC considers the current risk to the U.S. public from HPAI A(H5N1) viruses to be low; however, persons with exposure to infected animals, or contaminated materials, including raw cow's milk, are at higher risk for HPAI A(H5N1) virus infection and should take recommended precautions, including using recommended personal protective equipment. This table is intended for use by public health practitioners to help determine how best to prioritize monitoring and investigation efforts among higher risk persons when resources are limited. In summary, among groups exposed to HPAI A(H5N1) viruses, the highest risk for HPAI A(H5N1) virus infection is from close, direct, unprotected contact with animals with confirmed or suspected HPAI A(H5N1) virus infection or their environments and exposure to contaminated raw cow's milk from infected cows or other products made from contaminated raw cow's milk.

While data are still being gathered on the current outbreak, current risk assessments are based on expert opinion and supported by historical case examples from the literature. As additional data are gathered from the response, these assessments will be refined, and the risk category associated with some exposures may change.

High risk of exposure

Working on farms with poultry or cows with confirmed HPAI A(H5N1) virus infection or sick poultry or cows exposed to those with confirmed HPAI A(H5N1) virus infectionB ; known close animal contact

Examples of behaviors/activities

Working with poultry or cows with confirmed or suspected HPAI A(H5N1) virus infection in any capacity without appropriate personal protective equipment (PPE)

  • Milking cows
  • Getting splashed in face or eyes with raw milk from cows
  • Feeding or watering poultry or cows
  • Handling carcasses of dead cows, poultry culling, depopulation, butchering, evisceration

Providing veterinary care for poultry or cows with confirmed or suspected HPAI A(H5N1) virus infection (including veterinarians, veterinarian staff, farm owners or workers, animal health responders)

  • Medicating cows (e.g., instilling electrolyte solution down cow’s throat)
  • Handling, examining, taking specimens for testing (respiratory, blood, etc.)
  • Vaccinating cows
  • Poultry procedures such as debeaking or beak trimming, de-spurring, claw/toe trimming, dubbing/dewattling, feather plucking, wing clipping, Inspecting/examining poultry

Having experienced a breach in PPE, wearing inadequate PPE, or removing PPE incorrectly while handling or working with poultry or cows with confirmed or suspected HPAI A(H5N1) virus infection or their environments

Working in environments with poultry or cows with confirmed or suspected HPAI A(H5N1) virus infection

  • Cleaning and disinfecting cow pens, chicken coops or hen houses, poultry cages (e.g., shoveling or cleaning waste including urine/feces, using high pressure sprayer to clean pens, cleaning or replacing bedding)
  • Contact with contaminated fomites, feed or water
  • Performing activities in milking parlors (e.g., cleaning milking parlor or milk tanks, conducting bulk tank testing, collecting milk samples, dumping milk, pumping milk into bulk tanks)
  • Cleaning up after poultry depopulation (e.g., removal of poultry body parts, feathers, feces, organic material)

Working with calves (feeding non-heat-treated colostrum, bottle feeding raw milk, watering or medicating calves, cleaning calf pens)

Working in maternity pens (calving, providing post-partum care, handling aborted fetuses)

Handling other sick or dead animals (e.g., cats, wild birds, poultry) on premises with confirmed HPAI A(H5N1) virus infection in dairy cattle or poultry without appropriate PPE

  • Providing veterinary care
  • Feeding or watering animals
  • Handling carcasses

Non-workers living on dairy or poultry farm premises

Human A(H5) case data supporting risk assessments

Examples of direct/close contact with sick/dead animals with confirmed or suspected HPAI A(H5N1) virus infection.

  • TX and MI dairy farm cases from the current (2024) U.S. response fall into this category123
  • CO poultry farm cases from the current (2024) U.S. response4
  • CO poultry farm case from 2022 where worker involved in culling/depopulation5
  • Direct contact with sick/dead poultry6
  • Preparing sick/dead poultry for consumption; having sick/dead poultry in the household7
NEJM Review: Update on HPAI A(H5N1) virus infection in humans8 : Direct avian-to-human HPAI A(H5N1) virus transmission is the predominant means of human infection, although the exact mode and sites of HPAI A (H5N1) virus acquisition in the respiratory tract are incompletely understood. Handling of sick or dead poultry during the week before the onset of illness is the most common risk factor. Most patients have acquired HPAI A(H5N1) virus infection from poultry raised inside or outside their houses. Slaughtering, defeathering, or preparing sick poultry for cooking; and playing with or holding diseased or dead poultry have all been implicated as potential risk factors.

Drinking, consuming or exposure to contaminated raw cow’s milk from cows with confirmed or suspected HPAI A(H5N1) virus infection or other products made from contaminated raw cow’s milk

Currently, level of risk to humans is unknown but high level of concern based on available animal data

Examples of behaviors/activities

In settings where raw milk is obtained from cows with confirmed HPAI A(H5N1) virus infection or sick cows exposed to those with confirmed HPAI A(H5N1) virus infection

  • Drinking raw milk obtained directly from bulk tanks on farms
  • Drinking raw milk purchased at stores, restaurants, farmers markets
  • Eating or drinking other products made from contaminated raw cow’s milk purchased at farms, stores, restaurants, farmers markets

Human A(H5) case data supporting risk assessments

  • Researchers orally inoculated mice with HPAI A(H5N1) positive milk and found that animals showed signs of illness starting on Day 1. High virus titers were detected in respiratory organs, with medium titers in other organs suggesting systemic infection. Heat inactivation reduced H5 virus titers9 .
  • On dairy farms in Texas, deaths occurred in domestic cats fed raw colostrum and milk from cows with confirmed HPAI A(H5N1) virus infection. Clinical signs in sick cats included depressed mental status, ataxia, blindness and ocular and nasal discharge10 .

Slaughterhouse exposures to cows with confirmed or suspected HPAI A(H5N1) virus infection; known close animal contact

Examples of behaviors/activities

Working in slaughterhouses directly with cows with confirmed or suspected HPAI A(H5N1) virus infection without appropriate PPE

  • Unloading or handling live lactating dairy cows for slaughter
  • Working in holding pens
  • Performing antemortem inspections
  • Performing post-mortem inspections
  • Handling and transporting viscera
  • Removing and transporting udders for further processing or rendering

Close or prolonged contact with wild birds with confirmed HPAI A(H5N1) virus infection or their contaminated environments; known close bird contact

Examples of behaviors/activities

Risk would depend on extent of exposure to infected case as well as use of appropriate PPE

  • People in direct contact with sick or dead wild birds
  • People involved in depopulation/culling of wild birds
  • Wildlife agency employees in direct contact with sick or dead wild birds, including defeathering, carcass removal and disposal
  • Hunters who handle wild birds
  • Touching surfaces or materials (e.g., animal litter or bedding material) contaminated by wild birds with saliva, mucous, or feces
Human A(H5) case data supporting risk assessments

Close contact with and defeathering of wild swans was implicated as the source of exposure for two clusters of HPAI A(H5N1) in Azerbaijan11

Occupational exposure to poultry or other animals with confirmed or suspected HPAI A(H5N1) virus infection; known close animal contact

Examples of behaviors/activities
Working at a live bird market (e.g., handling poultry, feeding poultry, cleaning pens, slaughtering/evisceration, carcass and waste disposal)

Human A(H5) case data supporting risk assessments

  • HPAI A(H5N1) in live poultry markets121314
  • Environmental evidence of exposure risk from slaughtering sites and other live bird market worker areas in Indonesia15

Medium to high risk of exposure

Household members of a person with confirmed, probable, or suspected HPAI A(H5N1) virus infection; known close human contact

Examples of behaviors/activities

Prolonged unprotected contact with a household member with confirmed or suspected HPAI A(H5N1) virus infection

Human A(H5) case data supporting risk assessments

  • Unprotected prolonged bedside care in a hospital with exposure to respiratory secretions (kissing, wiping secretions) from a symptomatic family member in Thailand16
  • Unprotected, prolonged, close exposure including bedside care to a symptomatic blood-related family member in China and North Sumatra1718
  • Unprotected, prolonged, close exposure in households to a symptomatic blood-related family member in Pakistan and North Sumatra1819
Generally, spread of avian influenza from one infected person to a close contact has occurred only rarely

Working on a farm with poultry or cows with confirmed or suspected HPAI A(H5N1) virus infection or sick poultry or cows exposed to those with confirmed A(H5N1) virus infection; no close animal contact

Examples of behaviors/activities

Working on a farm with poultry or cows with confirmed or suspected HPAI A(H5N1) virus infection but with no known direct contact

  • Possible contact with poultry or cows of unknown infection status, asymptomatic or pre-symptomatic infection
  • Possible contact with contaminated environment
  • Possible contact with contaminated fomites
  • Possible contact with contaminated waste (feces, urine)
  • Possible contact with contaminated feed or water
Human A(H5) case data supporting risk assessments
Few HPAI A(H5N1) cases globally fall into a category of “no known poultry exposure” following investigation of exposures and epidemiologic links.

Medium risk of exposure

Non-farm occupational exposures to poultry or cows with suspected HPAI A(H5N1) virus infection or contaminated animal products (including raw milk); exposure unclear

Examples of behaviors/activities

These types of exposures could occur when a worker comes into contact with a bird or cow (or raw milk) that does not have a confirmed HPAI A(H5N1) virus infection, but comes from a farm that has other poultry or cows or animals with confirmed HPAI A(H5N1) virus infection (or other contaminated raw milk)

  • Transport-hauling milk
  • Working in milk processing or pasteurization plants
  • Working in milk or food testing laboratories
  • Transport-hauling cattle
  • Transport-hauling poultry
  • Working with animals in veterinary clinics
  • Working in slaughter houses
  • Unloading or handling live lactating dairy cows for slaughter
  • Working in holding pens
  • Performing antemortem inspections
  • Performing post-mortem inspections
  • Handling and transporting viscera
  • Removing and transporting udders for further processing or rendering

Time-limited visit to live bird market that has poultry or other animals with confirmed or suspected HPAI A(H5N1) virus infection; known close animal contact

Examples of behaviors/activities

Visiting a live bird market (retail poultry stalls or markets selling live poultry)

Human A(H5) case data supporting risk assessments
HPAI A(H5N1) in live poultry markets121314

Low to medium risk of exposure

Time-limited visit to farm with cows with confirmed HPAI A(H5N1) virus infection or sick cows exposed to those with confirmed HPAI A(H5N1) virus infection; no close animal contact

Examples of behaviors/activities

  • Visitors to farm
  • Delivery staff (feed, other farm-related materials)
  • Animal health outbreak responders
  • Public health responders
  • Nutritionists
  • Feed specialists

Health care workers exposed to person with confirmed or suspected HPAI A(H5N1) virus infection; known close human contact

Examples of behaviors/activities
Risk would depend on extent of exposure to infected case, including amount of time that a healthcare worker is in close proximity to the infected case and types of interactions (e.g., performing aerosol-generating procedures) as well as use of appropriate PPE


Human A(H5) case data supporting risk assessments

  • Serologic evidence of patient-to-health care worker transmission in Hong Kong in 199720
  • One case of severe illness was reported in a nurse exposed to an infected patient in Vietnam21

Non-farm recreational exposures to poultry or cows with confirmed or suspected HPAI A(H5N1) virus infection or contaminated animal products (including raw milk); known close animal contact


Examples of behaviors/activities

  • Fairs
  • Livestock shows/auctions
  • Petting Zoos
  • Backyard flock owners
  • Cockfighting
Agritourism (activities carried out on a farm or ranch that allow members of the general public to visit for recreational, entertainment, or educational purposes, including farming, milking cows, ranching, and harvesting, among other activities.

Human A(H5) case data supporting risk assessments

Variant influenza A virus infections (non-avian) acquired after exposure to pigs at fairs in the United States22

Environmental sample evidence of transmission from backyard chicken feces in China23

Case in the UK in 2022 associated with captive duck flock24

Low risk of exposure

Working on farms without poultry or cows with confirmed or suspected A(H5N1) virus infection or sick poultry or cows exposed to those with confirmed HPAI A(H5N1) virus infection; no known exposure

Examples of behaviors/activities

Workers or visitors to farm could be at increased risk if cows or other animals appear healthy but have asymptomatic or pre-symptomatic HPAI A(H5N1) infection.
Examples of activities that would typically only occur on farms without active outbreaks of HPAI A(H5N1) virus infection include:

  • Breeding cows or performing artificial insemination procedures
  • Trimming cow hooves
  • Performing layer poultry farm activities (e.g., insemination of hens, egg collection, inspection)
  • Working in hatcheries (e.g., insemination of hens, egg collection, inspection, incubation)

Consuming potentially raw or undercooked poultry products or eggs from poultry with confirmed HPAI A(H5N1) virus infection

Examples of behaviors/activities

In settings where meat and eggs are obtained from poultry with confirmed HPAI A(H5N1) virus infection or sick poultry exposed to those with confirmed HPAI A(H5N1) virus infection

  • Eating raw or undercooked meat or eggs

Human A(H5) case data supporting risk assessments
  • Consuming raw duck blood and organ products was implicated a potential source of exposure in two cases in Vietnam25
  • While HPAI A(H5N1) virus has been isolated from poultry muscle and the interior of eggs, a USDA assessment determined that the risk of infection from consumption is low26

Household members of a person with occupational exposure to poultry or cows or other animals with confirmed or suspected HPAI A(H5N1) virus infection; no known close animal contact

Examples of behaviors/activities

Household exposure via indirect transfer of virus from fomites (e.g., clothing, footwear) obtained from occupational exposure to potentially infected poultry or cows or other animals


Human A(H5) case data supporting risk assessments

Direct avian-to-human HPAI A(H5N1) virus transmission is the predominant means of human infection. Epidemiological links between affected premises are indirect from shared people, vehicles, and equipment27

A These risk assessments are based on historical data and limited data from the current outbreak; information in the table will be updated as additional data become available.

B Types of workers may include those who work only one farm as well as those who work or travel between multiple farms: farmers, farm workers, deadstock haulers, milk haulers, other contract haulers, feed deliverers, hoof trimmers, transport vehicles, veterinarians and veterinary staff, nutritionists, feed consultants, animal health responders, public health responders.

Attribution statement

N95 and NIOSH Approved are certification marks of the U.S. Department of Health and Human Services (HHS) registered in the United States and several international jurisdictions.

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Content Source:
National Center for Immunization and Respiratory Diseases (NCIRD)
  1. These risk assessments are based on historical data and limited data from the current outbreak; information in the table will be updated as additional data become available.
  2. Types of workers may include those who work only one farm as well as those who work or travel between multiple farms: farmers, farm workers, deadstock haulers, milk haulers, other contract haulers, feed deliverers, hoof trimmers, transport vehicles, veterinarians and veterinary staff, nutritionists, feed consultants, animal health responders, public health responders.
  1. Uyeki TM, Milton S, Abdul Hamid C, Reinoso Webb C, Presley SM, Shetty V, Rollo SN, Martinez DL, Rai S, Gonzales ER, Kniss KL, Jang Y, Frederick JC, De La Cruz JA, Liddell J, Di H, Kirby MK, Barnes JR, Davis CT. Highly Pathogenic Avian Influenza A(H5N1) Virus Infection in a Dairy Farm Worker. N Engl J Med. 2024 Jun 6;390(21):2028-2029. doi: 10.1056/NEJMc2405371. Epub 2024 May 3. PMID: https://pubmed.ncbi.nlm.nih.gov/38700506/
  2. Garg S, Reed C, Davis CT, Uyeki TM, Behravesh CB, Kniss K, Budd A, Biggerstaff M, Adjemian J, Barnes JR, Kirby MK, Basler C, Szablewski CM, Richmond-Crum M, Burns E, Limbago B, Daskalakis DC, Armstrong K, Boucher D, Shimabukuro TT, Jhung MA, Olsen SJ, Dugan V. Outbreak of Highly Pathogenic Avian Influenza A(H5N1) Viruses in U.S. Dairy Cattle and Detection of Two Human Cases - United States, 2024. MMWR Morb Mortal Wkly Rep. 2024 May 30;73(21):501-505. doi: 10.15585/mmwr.mm7321e1. PMID: https://pubmed.ncbi.nlm.nih.gov/38814843/
  3. CDC Confirms Second Human H5 Bird Flu Case in Michigan; Third Case Tied to Dairy Outbreak | CDC Online Newsroom | CDC
  4. CDC Confirms Human Cases of H5 Bird Flu Among Colorado Poultry Workers | CDC Online Newsroom | CDC
  5. U.S. Case of Human Avian Influenza A(H5) Virus Reported | CDC Online Newsroom | CDC
  6. Zhou L, Liao Q, Dong L, Huai Y, Bai T, Xiang N, Shu Y, Liu W, Wang S, Qin P, Wang M, Xing X, Lv J, Chen RY, Feng Z, Yang W, Uyeki TM, Yu H. Risk factors for human illness with avian influenza A (H5N1) virus infection in China. J Infect Dis. 2009 Jun 15;199(12):1726-34. doi: 10.1086/599206. PMID: https://pubmed.ncbi.nlm.nih.gov/19416076/
  7. Dinh PN, Long HT, Tien NT, Hien NT, Mai le TQ, Phong le H, Tuan le V, Van Tan H, Nguyen NB, Van Tu P, Phuong NT; World Health Organization/Global Outbreak Alert and Response Network Avian Influenza Investigation Team in Vietnam. Risk factors for human infection with avian influenza A H5N1, Vietnam, 2004. Emerg Infect Dis. 2006 Dec;12(12):1841-7. doi: 10.3201/eid1212.060829. PMID: https://pubmed.ncbi.nlm.nih.gov/17326934/
  8. Writing Committee of the Second World Health Organization Consultation on Clinical Aspects of Human Infection with Avian Influenza A (H5N1) Virus; Abdel-Ghafar AN, Chotpitayasunondh T, Gao Z, Hayden FG, Nguyen DH, de Jong MD, Naghdaliyev A, Peiris JS, Shindo N, Soeroso S, Uyeki TM. Update on avian influenza A (H5N1) virus infection in humans. N Engl J Med. 2008 Jan 17;358(3):261-73. doi: 10.1056/NEJMra0707279. PMID: https://www.nejm.org/doi/pdf/10.1056/NEJMra0707279
  9. Guan L, Eisfeld AJ, Pattinson D, et al. Cow's Milk Containing Avian Influenza A(H5N1) Virus - Heat Inactivation and Infectivity in Mice. N Engl J Med. 2024 May 24. doi: 10.1056/NEJMc2405495. Epub ahead of print. PMID: https://www.nejm.org/doi/full/10.1056/NEJMc2405495
  10. Burrough ER, Magstadt DR, Petersen B, et al. Highly Pathogenic Avian Influenza A(H5N1) Clade 2.3.4.4b Virus Infection in Domestic Dairy Cattle and Cats, United States, 2024. Emerg Infect Dis. 2024 Apr 29;30(7). doi: 10.3201/eid3007.240508. Epub ahead of print. PMID: 38683888. https://wwwnc.cdc.gov/eid/article/30/7/24-0508_article
  11. Gilsdorf A, Boxall N, Gasimov V, Agayev I, Mammadzade F, Ursu P, Gasimov E, Brown C, Mardel S, Jankovic D, Pimentel G, Ayoub IA, Elassal EM, Salvi C, Legros D, Pessoa da Silva C, Hay A, Andraghetti R, Rodier G, Ganter B. Two clusters of human infection with influenza A/H5N1 virus in the Republic of Azerbaijan, February-March 2006. Euro Surveill. 2006;11(5):122-6. PMID: https://pubmed.ncbi.nlm.nih.gov/16757853/
  12. Mounts AW, Kwong H, Izurieta HS, Ho Y, Au T, Lee M, Buxton Bridges C, Williams SW, Mak KH, Katz JM, Thompson WW, Cox NJ, Fukuda K. Case-control study of risk factors for avian influenza A (H5N1) disease, Hong Kong, 1997. J Infect Dis. 1999 Aug;180(2):505-8. doi: 10.1086/314903. PMID: https://pubmed.ncbi.nlm.nih.gov/10395870/
  13. Nasreen S, Khan SU, Luby SP, Gurley ES, Abedin J, Zaman RU, Sohel BM, Rahman M, Hancock K, Levine MZ, Veguilla V, Wang D, Holiday C, Gillis E, Sturm-Ramirez K, Bresee JS, Rahman M, Uyeki TM, Katz JM, Azziz-Baumgartner E. Highly pathogenic Avian Influenza A(H5N1) virus infection among workers at live bird markets, Bangladesh, 2009-2010. Emerg Infect Dis. 2015 Apr;21(4):629-37. doi: 10.3201/eid2104.141281. PMID: https://pubmed.ncbi.nlm.nih.gov/25811942/
  14. Wang M, Di B, Zhou DH, Zheng BJ, Jing H, Lin YP, Liu YF, Wu XW, Qin PZ, Wang YL, Jian LY, Li XZ, Xu JX, Lu EJ, Li TG, Xu J. Food markets with live birds as source of avian influenza. Emerg Infect Dis. 2006 Nov;12(11):1773-5. doi: 10.3201/eid1211.060675. PMID: https://pubmed.ncbi.nlm.nih.gov/17283635/
  15. Indriani R, Samaan G, Gultom A, Loth L, Irianti S, Adjid R, Dharmayanti NL, Weaver J, Mumford E, Lokuge K, Kelly PM, Darminto. Environmental sampling for avian influenza virus A (H5N1) in live-bird markets, Indonesia. Emerg Infect Dis. 2010 Dec;16(12):1889-95. doi: 10.3201/eid1612.100402. Erratum in: Emerg Infect Dis. 2013 May;19(5):841. Indryani, Sri [corrected to Irianti, Sri]. PMID: https://pubmed.ncbi.nlm.nih.gov/21122218/
  16. Ungchusak K, Auewarakul P, Dowell SF, Kitphati R, Auwanit W, Puthavathana P, Uiprasertkul M, Boonnak K, Pittayawonganon C, Cox NJ, Zaki SR, Thawatsupha P, Chittaganpitch M, Khontong R, Simmerman JM, Chunsutthiwat S. Probable person-to-person transmission of avian influenza A (H5N1). N Engl J Med. 2005 Jan 27;352(4):333-40. doi: 10.1056/NEJMoa044021. Epub 2005 Jan 24. PMID: https://pubmed.ncbi.nlm.nih.gov/15668219/
  17. Wang H, Feng Z, Shu Y, Yu H, Zhou L, Zu R, Huai Y, Dong J, Bao C, Wen L, Wang H, Yang P, Zhao W, Dong L, Zhou M, Liao Q, Yang H, Wang M, Lu X, Shi Z, Wang W, Gu L, Zhu F, Li Q, Yin W, Yang W, Li D, Uyeki TM, Wang Y. Probable limited person-to-person transmission of highly pathogenic avian influenza A (H5N1) virus in China. Lancet. 2008 Apr 26;371(9622):1427-34. doi: 10.1016/S0140-6736(08)60493-6. Epub 2008 Apr 8. PMID: https://pubmed.ncbi.nlm.nih.gov/18400288/
  18. Avian influenza – situation in Indonesia – update 15 (who.int)
  19. Human cases of avian influenza A (H5N1) in North-West Frontier Province, Pakistan, October-November 2007. Wkly Epidemiol Rec. 2008 Oct 3;83(40):359-64. English, French. https://iris.who.int/bitstream/handle/10665/241212/WER8340_359-364.PDF
  20. Buxton Bridges C, Katz JM, Seto WH, Chan PK, Tsang D, Ho W, Mak KH, Lim W, Tam JS, Clarke M, Williams SG, Mounts AW, Bresee JS, Conn LA, Rowe T, Hu-Primmer J, Abernathy RA, Lu X, Cox NJ, Fukuda K. Risk of influenza A (H5N1) infection among health care workers exposed to patients with influenza A (H5N1), Hong Kong. J Infect Dis. 2000 Jan;181(1):344-8. doi: 10.1086/315213. PMID: https://pubmed.ncbi.nlm.nih.gov/10608786/
  21. Beigel JH, Farrar J, Han AM, Hayden FG, Hyer R, de Jong MD, Lochindarat S, Nguyen TK, Nguyen TH, Tran TH, Nicoll A, Touch S, Yuen KY; Writing Committee of the World Health Organization (WHO) Consultation on Human Influenza A/H5. Avian influenza A (H5N1) infection in humans. N Engl J Med. 2005 Sep 29;353(13):1374-85. doi: 10.1056/NEJMra052211. Erratum in: N Engl J Med. 2006 Feb 23;354(8):884. PMID: https://www.nejm.org/doi/pdf/10.1056/NEJMra052211
  22. Greenbaum A, Quinn C, Bailer J, Su S, Havers F, Durand LO, Jiang V, Page S, Budd J, Shaw M, Biggerstaff M, de Fijter S, Smith K, Reed C, Epperson S, Brammer L, Feltz D, Sohner K, Ford J, Jain S, Gargiullo P, Weiss E, Burg P, DiOrio M, Fowler B, Finelli L, Jhung MA. Investigation of an Outbreak of Variant Influenza A(H3N2) Virus Infection Associated With an Agricultural Fair-Ohio, August 2012. J Infect Dis. 2015 Nov 15;212(10):1592-9. doi: 10.1093/infdis/jiv269. Epub 2015 May 5. PMID: https://pubmed.ncbi.nlm.nih.gov/25948864/; Notes from the field: Outbreak of influenza A (H3N2) virus among persons and swine at a county fair--Indiana, July 2012 - PubMed (nih.gov)
  23. Ayala AJ, Haas LK, Williams BM, Fink SS, Yabsley MJ, Hernandez SM. Risky business in Georgia's wild birds: contact rates between wild birds and backyard chickens is influenced by supplemental feed. Epidemiol Infect. 2022 May 5;150:e102. doi: 10.1017/S0950268822000851. PMID: https://pubmed.ncbi.nlm.nih.gov/35508913/
  24. Oliver I, Roberts J, Brown CS, Byrne AM, Mellon D, Hansen R, Banyard AC, James J, Donati M, Porter R, Ellis J, Cogdale J, Lackenby A, Chand M, Dabrera G, Brown IH, Zambon M. A case of avian influenza A(H5N1) in England, January 2022. Euro Surveill. 2022 Feb;27(5):2200061. doi: 10.2807/1560-7917.ES.2022.27.5.2200061. PMID: https://pubmed.ncbi.nlm.nih.gov/35115075/
  25. https://www.who.int/emergencies/disease-outbreak-news/item/2005_01_21-en
  26. https://www.fsis.usda.gov/news-events/publications/interagency-risk-assessment-public-health-impact-highly-pathogenic-avian
  27. https://www.aphis.usda.gov/sites/default/files/hpai-h5n1-dairy-cattle-mi-epi-invest.pdf