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18 January 2023
Situation at a glance
On 9 January 2023, WHO was notified of a human infection caused by an avian influenza A(H5) virus. The case, a nine-year-old girl, living in a rural area in the province of Bolívar, Ecuador, was in contact with backyard poultry, which was acquired a week before the onset of her symptoms. She is currently hospitalized, in isolation, and is being treated with antivirals.
This is the first reported case of human infection caused by avian influenza A(H5) virus in the Latin America and the Caribbean region. Work is ongoing to further characterize the virus.
Currently, available epidemiological and virological evidence suggests that influenza A(H5) viruses have not acquired the ability for sustained transmission among humans, thus the likelihood of human-to-human spread is low.
Description of the situation
On 9 January 2023, the Ecuador IHR National Focal Point (NFP) informed WHO of a human case of infection with an avian influenza A(H5) virus. The case was detected as part of severe acute respiratory infection (SARI) sentinel surveillance and was confirmed by the National Influenza Centre (NIC), the National Institute of Public Health Research (INSPI per its acronym in Spanish).
The case is a nine-year-old girl, with no known comorbidities, from Bolívar Province, Ecuador. She developed symptoms of conjunctival pruritus and coryza on 25 December 2022. On 27 December, she was brought to a local health center for medical evaluation and treatment.  On 30 December, due to the persistent symptoms including nausea, vomiting and constipation, she was admitted to a general hospital where empirical treatment for meningitis was started with antibiotics and antipyretics. On 3 January 2023, she was transferred to a pediatric hospital in critical condition where she was admitted to the intensive care unit (ICU) with septic shock and was treated with antivirals and mechanical ventilation due to pneumonia.
On 5 January, as part of SARI surveillance activities, a nasopharyngeal sample was collected from the patient. The sample was sent to INSPI and tested positive for influenza A(H5) by reverse transcription-polymerase chain reaction (RT-PCR) on 7 January.
As of 17 January, the patient remains hospitalized, under isolation, and with noninvasive mechanical ventilation.
According to the epidemiological investigation in response to the outbreak, a week before the onset of her symptoms, the family acquired poultry which died without apparent cause on 19 December 2022. In addition, the epidemiological investigations revealed that several incidents of dead backyard poultry (chickens and ducks) have been reported from the same community where the family resided.
Epidemiology of disease
Zoonotic influenza infections in humans may be asymptomatic or may cause disease, from conjunctivitis or mild, flu-like symptoms to severe, acute respiratory disease or even death, depending on factors related to the virus causing infection and the infected host. Rarely, gastrointestinal or neurological symptoms have been reported.
Human cases of infection with avian influenza viruses are usually the result of direct or indirect exposure to infected live or dead poultry or contaminated environments.

Public health response

Public health measures from both human and animal health agencies have been implemented. These include:

  • Local authorities carried out epidemiological investigations and follow-up of the case’s contacts in the family, home, and health care facilities.
  • Ongoing intersectoral activities with the Ministry of Agriculture and Livestock (MAG), and the Phytosanitary and Animal Health Regulation and Control Agency (Agrocalidad) for active detection, follow-up and control of avian influenza outbreaks in the area.
  • Continuous follow-up of persons with respiratory symptoms and suspected influenza cases due to contact with poultry or/and who have been exposed to birds, among the exposed population.
  • Seasonal influenza vaccination in risk groups is ongoing according to the guidelines of the National Immunization Program.
  • The NIC is in the process of sending the patient’s samples to a WHO Collaborating Center for further characterization.

 

WHO risk assessment

This is the first reported case of human infection caused by avian influenza A(H5) virus in Ecuador and in Latin America and the Caribbean. This human case was exposed to poultry, which died without apparent cause. Outbreaks of highly pathogenic avian influenza have been detected recently in the provinces of Cotopaxi (influenza A(H5N1)) and Bolívar, Ecuador.

Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, human cases are expected, although rare.

According to the information received thus far, the virus has not been detected in other individuals beyond this single case. While further characterization of the virus from this case is pending, currently available epidemiological and virological evidence suggests that influenza A(H5) viruses have not acquired the ability for sustained transmission among humans, thus the likelihood of human-to-human spread is low. Based on available information, WHO assesses the risk to the general population posed by this virus to be low. The risk assessment will be reviewed as needed should further epidemiological or virological information become available.

A global risk assessment associated with recent influenza A(H5N1) clade 2.3.4.4b viruses was published on 21 December 2022. However, the subtype and clade information for this human case is not yet known.

There are no approved vaccines for preventing influenza A(H5) in humans. Candidate vaccines to prevent influenza A(H5) infection in humans have been developed for pandemic preparedness purposes.

Close analysis of the epidemiological situation, further characterization of the most recent viruses (human and poultry) and serological investigations are critical to assess associated risk and to adjust risk management measures in a timely manner.

WHO advice

The reported case does not change the current WHO recommendations on public health measures and surveillance of influenza.
WHO does not advise special traveler screening at points of entry or restrictions regarding the current situation of influenza viruses at the human-animal interface.
Due to the constantly evolving nature of influenza viruses, WHO continues to stress the importance of global surveillance to detect and monitor virological, epidemiological, and clinical changes associated with emerging or circulating influenza viruses that may affect human (or animal) health, and timely virus sharing for risk assessment. The diversity of zoonotic influenza viruses that have caused human infections is alarming and necessitates strengthened surveillance in both animal and human populations, thorough investigation of every zoonotic infection and pandemic preparedness. Vaccination against seasonal influenza infection of selected groups at increased risk of exposure to animal influenza viruses could be considered as a measure to reduce opportunities for the simultaneous infection of humans with animal and human influenza viruses.
In the case of a confirmed or suspected human infection caused by a novel influenza virus with pandemic potential, including a variant virus, the health authorities should be notified and appropriate clinical case management, including testing, triage, clinical assessment for disease severity classification, assessment of risk factors for severe disease and isolation and treatment (e.g., antivirals and supportive care) should be provided. A thorough epidemiologic investigation (even while awaiting the confirmatory laboratory results) of a history of exposure to animals, and travel, and contact tracing should be conducted.  The epidemiologic investigation should include early identification of unusual respiratory events that could signal person-to-person transmission of the novel virus. Clinical samples should be tested and sent to a WHO Collaboration Centre for further characterization.
Travelers to countries with known outbreaks of animal influenza should avoid farms, contact with animals in live animal markets, entering areas where animals may be slaughtered, or contact with any surfaces that appear to be contaminated with animal faeces. Travelers should also wash their hands often with soap and water. Travelers should follow good food safety and hygiene practices. Should infected individuals from affected areas travel internationally, their infection may be detected in another country during travel or after arrival. If this were to occur, further community level spread is considered unlikely as this virus has not acquired the ability to transmit easily among humans.
All human infections caused by a novel influenza subtype are notifiable under the International Health Regulations (IHR) and State Parties to the IHR (2005) are required to immediately notify WHO of any laboratory-confirmed case of a recent human infection caused by an influenza A virus with the potential to cause a pandemic. Evidence of illness is not required for this notification.
WHO does not recommend any restrictions on travel and/or trade for Ecuador based on available information on this event.

Further information

Citable reference: World Health Organization (18 January 2023). Disease Outbreak News; Human infection caused by avian influenza A(H5) –  Ecuador. Available at https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON434

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