H5N1

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

A WHO DON: 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.  

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).

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).

Agricultural and geographic factors shaped the North American 2015 HPAI H5N2 outbreak

Via bioRxiv: Agricultural and geographic factors shaped the North American 2015 highly pathogenic avian influenza H5N2 outbreak. The abstract:

The 2014 – 2015 highly pathogenic avian influenza (HPAI) H5NX outbreak represents the largest and most expensive HPAI outbreak in the United States to date. Despite extensive traditional and molecular epidemiological studies, factors associated with the spread of HPAI among midwestern poultry premises remain unclear. 

To better understand the dynamics of this outbreak, 182 full genome HPAI H5N2 sequences isolated from commercial layer chicken and turkey production premises were analyzed using evolutionary models modified to incorporate epidemiological and geographic information. Epidemiological compartmental models constructed in a phylogenetic framework provided evidence that poultry type acted as a barrier to the transmission of virus among midwestern poultry farms. 

Furthermore, after initial introduction, a continuous external source of virus was not needed to explain the propagation of HPAI cases within the commercial poultry industries. Discrete trait diffusion models indicated that within state viral transitions occurred more frequently than inter-state transitions. Distance, road density and proportion of water coverage were all supported as associated with viral transition between county groups (Bayes Factor > 3.0). 

Together these findings indicate that the midwestern poultry industries were not a single homogenous population, but rather, the outbreak was shaped by poultry sectors and geographic factors.

ECDC surveillance report: Avian influenza overview May – August 2018

ECDC has published Surveillance report: Avian influenza overview May – August 2018. The executive summary:

Between 16 May and 15 August 2018, three highly pathogenic avian influenza (HPAI) A(H5N8) outbreaks in poultry establishments and three HPAI A(H5N6) outbreaks in wild birds were reported in Europe. Three low pathogenic avian influenza (LPAI) outbreaks were reported in three Member States. Few HPAI and LPAI bird cases have been detected in this period of the year, in accordance with the seasonal expected pattern of LPAI and HPAI. 

There is no evidence to date that HPAI A(H5N8) and A(H5N6) viruses circulating in Europe have caused any human infections. The risk of zoonotic transmission to the general public in Europe is considered to be very low. 

Several HPAI outbreaks in poultry were reported during this period from Russia. The presence of the A(H5N2) and A(H5N8) viruses in parts of Russia connected with fall migration routes of wild birds is of concern for possible introduction and spread with wild birds migrating to the EU. 

Although few AI outbreaks were observed in Africa, Asia and the Middle East during the reporting period, the probability of AI virus introductions from non-EU countries via wild birds particularly via the north-eastern route from Russia is increasing, as the fall migration of wild birds will start in the coming weeks. Further, the lower temperatures in autumn and winter may facilitate the environmental survival of avian influenza viruses potentially introduced to Europe. 

Vietnam warns of possible new bird flu outbreaks

Via Xinhua: Vietnam warns of possible new bird flu outbreaks. Interestingly, it doesn't mention H5N1, which was a recurring problem in Vietnam for years.

The Department of Animal Health under the Ministry of Agriculture and Rural Development has warned of a high risk of the return of avian influenza in Vietnam after the epidemic was put under control for a long period of time.  

The department said one hotbed of A/H5N6 bird flu virus had been reported recently in Dai Ban commune, An Duong district, northern Hai Phong city, Vietnam News Agency reported on Monday.

It noted some avian flu strains that have not been reported in Vietnam such as A/H7N9, A/H5N2 and A/H5N8 may enter the country through the transportation, trading and consumption of poultry and poultry products with obscure origin, especially in border provinces and the localities consuming smuggled poultry products. 

The department urged localities to take the initiative in bird flu prevention, crack down on poultry smuggling, and keep a close watch on local situation in order to timely respond to any outbreak. 

Meanwhile, foot-and-mouth and blue-ear diseases are also likely to break out among livestock that are unvaccinated or transported to former hotbeds.  

The animal health agency called on vulnerable localities to augment monitoring, vaccination and control of livestock transportation and slaughtering to minimize risks of disease outbreak and spread.

Vietnam: Bird flu outbreak casts pall over Tết

Via VietNam News: Bird flu outbreak casts pall over Tết. Excerpt:

The Ministry of Health urged city and provincial people’s committees, health departments and citizens across the country to take preventions against a possible bird flu over the next 16 days ahead of the Lunar New Year and during first months of the new year.  

Trần Đắc Phu, Director of the Department of Preventive Medicine at the Ministry, said that the urgent recommendation came after evaluations during the late months of 2017 and early 2018 showing that newly-emerging infectious diseases such as Mers - CoV continue to be reported in the Middle East, along with influenza A/ H7N9 in China, nld.com.vn online newspaper reported. 

Meanwhile in Việt Nam, influenza A / H5N1 and A / H5N6 continue to occur in poultry in many areas and are at risk of transmission to humans. 

According to Phu, from January 17 to 19, bird flu was detected at a poultry-breeding farm in Diễn Châu District, the central province of Nghệ An.  

Nearly 200 of the 800 poultry at the farm died, while the farm’s owner reported his poultry herd wasn’t vaccinated against bird flu.  

The Department of Animal Health at the Ministry of Agriculture and Rural Development has warned that many types of influenza A /H7N9 virus and other highly virulent strains such as A/ H5N2, A/H5N8 that haven’t yet appeared in Việt Nam are at risk of entering the country.  

The main route of transmission was smuggling of poultry and unknown-origin poultry products. Therefore, the Department of Animal Health asked local authorities to be active in prevention and controlling the threat of bird flu outbreaks, strengthen inspection and strictly tackle poultry smuggling and illegal transporting.  

Local authorities and relevant departments should closely monitor the situation to ensure timely action against outbreaks. 

About the possibility of a bird flu outbreak in the Tết period and first months of the new year, the Ministry of Health warned the disease could present a complicated challenge due to the spring weather, people’s over-use of food during and after Tết holidays and high travel demand. All these factors increase the risk of transmission. 

Nguyễn Văn Kính, Director of the Central Tropical Disease Hospital, said the cold and humid weather was creating conditions for influenza viruses to develop. At some clinics, many patients were reported with seasonal influenza viruses such as H1N1 and H3N2, but the clinical symptoms were very severe.

Taiwan reports new H5N2 bird flu cases

Via Xinhua: Taiwan reports new bird flu cases.

Taiwan has confirmed new outbreaks of bird flu at two farms in Changhua County, and culled more than 13,000 chickens and ducks, the island's animal and plant health inspection and quarantine bureau said on Saturday.  

More than 6,000 chickens at a farm in Dacheng Township, Changhua County died several days ago, and were confirmed to be infected with the highly pathogenic H5N2 strain of avian influenza, which led to the slaughter of over 12,000 chickens.  

Another farm in Changhua's Erlin Township was also confirmed to have the virus, with more than 1,300 ducks being culled.  

That brings the total number of poultry farms hit by avian influenza to 12 so far this year, and the total number of fowls culled to 115,055, according to the bureau.  

Taiwan is a common destination for migrating birds. Cases of avian flu generally peak during the cool season from January to April.

Taiwan reports new outbreak of bird flu

Via Xinhua: Taiwan reports new outbreak of bird flu. Excerpt:

Taiwan has confirmed a new outbreak of bird flu at a duck farm, and culled about 39,000 ducks, according to the island's animal and plant health inspection and quarantine bureau. 

Ducks at a large farm in Yenpu town, Pingdong county, in the southern region of Taiwan were confirmed to be infected with the highly pathogenic H5 sub-type of the avian influenza virus, the bureau said Friday night. 

The virus was likely to be the H5N2 strain because the affected duck farm is located close to farms where other H5N2 cases have emerged. A chicken farm in the same town was confirmed to have the H5N2 flu strain on Dec. 29, the bureau said. 

There are many open duck farms in the same area, and disinfection work will be strengthened, according to the bureau.

Egypt slaughters 17,500 poultry after bird flu outbreak reported

Via Egypt Today, a December 31 report: Egypt slaughters 17.5K poultry after bird flu outbreak reported. Excerpt:

Egypt has slaughtered more than 17,500 poultry in a farm where bird flu cases were reported in the Dakahlia governorate (Delta), said Head of Veterinary Medicine Directorate, Abdel Moneim Al Mongy, on Saturday. 

After taking samples from infected poultry, vets buried the dead and slaughtered poultry to control the spread of viruses, Mongy added in remarks to Al-Watan newspaper. 

Dakahlia’s Mit Ghamr and Gharbyia’s Santa cities were ranked as the most dangerous places, as they have the virus, he continued. 

During the veterinary inspection, the vets reported new H5N2, H8N2, H9N2 and IB strains. The fact that these strains are appearing for the first time in Egypt has made the situation all the more serious. 

“After the death of my poultry, I informed the Veterinary Medicine (Directorate) immediately,” the owner of the farm, Maged Atman, confirmed. The government should produce local veterinary medicine to cure the local virus strains and stop exporting drugs for strains not existing in Egypt, Mongy stated.

The virus first appeared in Egypt in 2006, and caused 41 deaths during 2015. Most cases are detected in impoverished rural areas that raise poultry.

See also this FluTrackers report, posted yesterday. H8N2 is a new strain to me. 

Russia reports virulent H5N2 bird flu at 660,000-bird farm

Via VOA: Russia Reports Virulent H5N2 Bird Flu at 660,000-bird Farm. Excerpt:

Russia has reported an outbreak of highly pathogenic H5N2 bird flu on a farm in the central region of Kostromskaya Oblast that led to the deaths of more than 660,000 birds, the Paris-based World Organization for Animal Health (OIE) said Friday.  

The virus killed more than 44,000 birds in an outbreak first detected on December 17, the OIE said, citing a report from the Russian Ministry of Agriculture. 

The rest of the 663,500 birds on the farm were slaughtered, it said in the report. It did not specify the type of birds that were infected. 

It is the first outbreak of the H5N2 strain in Russia this year, but the country has been facing regular outbreaks of H5N8 since early December last year, with the last one reported to the OIE detected late November. 

Bird flu has led to the deaths or culling of more than 2.6 million birds on farms between December last year and November this year, a report posted on the OIE website showed.  

Neither the H5N2 or H5N8 strains has been found in humans.

Mike Coston at Avian Flu Diary had this story yesterday, with more details.