H5N1

WHO: Avian Influenza A (H5N1) - Australia

A WHO DON: Avian Influenza A (H5N1) - Australia. Excerpt:

Situation at a glance  

On 22 May 2024, the World Health Organization (WHO) was notified of a laboratory-confirmed case of human infection with avian influenza A(H5N1) virus (clade 2.3.2.1a) by the International Health Regulations (IHR) National Focal Point (NFP) of Australia. This is the first confirmed human infection caused by avian influenza A(H5N1) virus detected and reported by Australia.  

Although the source of exposure to the virus in this case is currently unknown, the exposure likely occurred in India, where the case had travelled, and where this clade of A(H5N1) viruses has been detected in birds in the past. According to the IHR (2005), a human infection caused by a novel influenza A virus subtype is an event that has the potential for high public health impact and must be notified to the WHO. Based on available information, WHO assesses the current risk to the general population posed by this virus as low.  

Description of the situation  

On 17 May 2024, the WHO Collaborating Centre (WHO CC) for Reference and Research on Influenza in Australia notified the NFP of Australia of a suspected case of human A(H5N1) avian influenza (HPAI) in Melbourne, Victoria. The state Victorian Department of Health confirmed this case on 18 May 2024. Under Article 44, the NFP of Australia advised the NFP of India of the confirmed case on 21 May 2024. Under Article 8, the IHR NFP of Australia notified WHO of the case on 22 May 2024.  

The case is a 2.5-year-old female child with no underlying conditions.  She had a history of travel to Kolkata, India from 12 to 29 February 2024. She returned to Australia on 1 March 2024. Upon returning to Australia, the child presented at a hospital in Victoria on 2 March 2024, where she received medical care and was admitted on the same day. 

On 4 March, the patient was transferred to the intensive care unit at a referral hospital in Melbourne, Victoria, due to worsening symptoms, for a period of one week. The patient was discharged from hospital after a 2.5-week admission. The case is now reported to be clinically well.  

The Victorian Department of Health reported on 23 May 2024 that the family advised that the child started to feel unwell on 25 February 2024, with loss of appetite, irritability and fever, and was taken to a doctor on the evening of 28 February 2024 in India. She was febrile, coughing and vomiting and was given paracetamol. It was not reported to an Australian airport biosecurity officer that the child was unwell when she arrived in Australia on 1 March 2024.  

Additional information provided by the family indicates that the case did not travel outside of Kolkata, India, and did not have any known exposure to sick persons or animals while in India. It is understood that no close family contacts of the case in Australia or India developed symptoms, as of 22 May 2024.  

A nasopharyngeal swab and endotracheal aspirate taken on 6 and 7 March respectively tested positive for influenza A at the referral hospital. The samples were sent to the WHO CC for further characterisation on 3 April as part of a batch, as there was insufficient knowledge from the referring practitioners at the hospital to connect the case to the H5N1 virus.  

Virus genetic sequence obtained from the samples confirmed the subtype A(H5N1) and indicated that the haemagglutinin (HA) gene belonged to clade 2.3.2.1a, which circulates in South-East Asia and has been detected in previous human infections and in poultry.

Cows infected with bird flu have died in five US states

Via Reuters: Exclusive: Cows infected with bird flu have died in five US states. I sincerely hope that sick cows sent to slaughter do not then enter the food chain. Excerpt:

June 6 (Reuters) - Dairy cows infected with avian flu in five U.S. states have died or been slaughtered by farmers because they did not recover, state officials and academics told Reuters.  

Reports of the deaths suggest the bird flu outbreak in cows could take a greater economic toll in the farm belt than initially thought. Farmers have long culled poultry infected by the virus, but cows cost much more to raise than chickens or turkeys. 

A U.S. Department of Agriculture spokesperson said the agency knew of a few deaths but that the vast majority of cows recover well. Reuters was not able to determine the total number of cows with bird flu that died or were killed in South Dakota, Michigan, Texas, Ohio and Colorado.  

Avian flu has infected dairy cows in more than 80 herds across 10 states since late March, according to the USDA.  

Some of the animals died of secondary infections contracted after bird flu weakened their immune systems, said state veterinarians, agriculture officials, and academics assisting in state responses to bird flu. Other cows were killed by farmers because they failed to recover from the virus.  

Cattle infected with bird flu suffer reduced milk production, digestive issues, fever, and diminished appetite, according to farmers and veterinarians.  

In South Dakota, a 1,700-cow dairy sent a dozen of the animals to slaughter after they did not recover from the virus, and killed another dozen that contracted secondary infections, said Russ Daly, a professor with South Dakota State University and veterinarian for the state extension office who spoke with the farm. 

"You get sick cows from one disease, then that creates a domino effect for other things, like routine pneumonia and digestive issues," Daly said.  

A farm in Michigan killed about 10% of its 200 infected cows after they too failed to recover from the virus, said Phil Durst, an educator with Michigan State University Extension who spoke with that farm.

WHO: Human infection caused by avian Influenza A(H5N2)- Mexico

A Disease Outbreak News report from WHO: Human infection caused by avian Influenza A(H5N2)- Mexico. Excerpt:

Situation at a glance

On 23 May 2024, the Mexico International Health Regulations (IHR) National Focal Point (NFP) reported to PAHO/WHO a confirmed fatal case of human infection with avian influenza A(H5N2) virus detected in a resident of the State of Mexico who was hospitalized in Mexico City.  

This is the first laboratory-confirmed human case of infection with an influenza A(H5N2) virus reported globally and the first avian H5 virus infection in a person reported in Mexico. Although the source of exposure to the virus in this case is currently unknown, A(H5N2) viruses have been reported in poultry in Mexico. According to the IHR (2005), a human infection caused by a novel influenza A virus subtype is an event that has the potential for high public health impact and must be notified to the WHO. 

Based on available information, WHO assesses the current risk to the general population posed by this virus as low.   

Description of the situation  

On 23 May 2024, the Mexico IHR NFP reported to PAHO/WHO a confirmed case of human infection with avian influenza A(H5N2) virus detected in a 59-year-old resident of the State of Mexico who was hospitalized in Mexico City and had no history of exposure to poultry or other animals. The case had multiple underlying medical conditions. The case’s relatives reported that the case had already been bedridden for three weeks, for other reasons, prior to the onset of acute symptoms.  

On 17 April, the case developed fever, shortness of breath, diarrhoea, nausea and general malaise. On 24 April, the case sought medical attention, was hospitalized at the National Institute of Respiratory Diseases “Ismael Cosio Villegas” (INER per its acronym in Spanish) and died the same day due to complications of his condition.  

Results from Real-Time Polymerase Chain Reaction (RT-PCR) of a respiratory sample collected and tested at INER on 24 April indicated a non-subtypeable influenza A virus. On 8 May, the sample was sent for sequencing to the Laboratory of Molecular Biology of Emerging Diseases Center for Research in Infectious Diseases (CIENI per its acronym in Spanish) of INER, which indicated that the sample was positive for influenza A(H5N2).  

On 20 May, the sample was received at the Institute of Epidemiological Diagnosis and Reference (InDRE per its acronym in Spanish) of the Mexico National Influenza Centre, for analysis by RT-PCR, obtaining a positive result for influenza A. On 22 May, sequencing of the sample confirmed the influenza subtype was A(H5N2).  

No further cases were reported during the epidemiological investigation. Of the 17 contacts identified and monitored at the hospital where the case died, one reported a runny nose between 28 and 29 April. Samples taken from these hospital contacts between 27 and 29 May tested negative for influenza and SARS-CoV 2.  

Twelve additional contacts (seven symptomatic and five asymptomatic) were identified near the case's residence. Samples of pharyngeal exudate, nasopharyngeal swabs and serum were obtained from these individuals. On 28 May, the InDRE reported that all twelve samples from contacts near the patient's residence tested negative for SARS-CoV-2, influenza A and influenza B, as determined by RT-PCR. The results of the serological samples are pending.  

In March 2024, a high pathogenicity avian influenza A(H5N2) outbreak was detected in a backyard poultry farm in the state of Michoacán, which borders the State of Mexico where the case was residing  

Additionally, in March 2024, an outbreak of low pathogenicity avian influenza (LPAI) A(H5N2) was identified in poultry in Texcoco, State of Mexico, and a second outbreak of LPAI A(H5N2) in April in the municipality of Temascalapa in the same state. Thus far, it has not been possible to establish if this human case is related to the recent poultry outbreaks (1).  

A study describing the continuous circulation of low pathogenicity avian influenza H5N2 viruses in Mexico and spread to several other countries was published in 2022 (2).