Retrospective #modelling of the #disease and #mortality burden of the 1918–1920 #influenza #pandemic in #Zurich, #Switzerland

Abstract

Background

Our study aims to enhance future pandemic preparedness by integrating lessons from historical pandemics, focusing on the multidimensional analysis of past outbreaks. It addresses the gap in existing modelling studies by combining various pandemic parameters in a comprehensive setting. Using Zurich as a case study, we seek a deeper understanding of pandemic dynamics to inform future scenarios.

Data and methods

We use newly digitized weekly aggregated epidemic/pandemic time series (incidence, hospitalisations, mortality and sickness absences from work) to retrospectively model the 1918–1920 pandemic in Zurich and investigate how different parameters correspond, how transmissibility changed during the different waves, and how public health interventions were associated with changes in these pandemic parameters.

Results

In general, the various time series show a good temporal correspondence, but differences in their expression can also be observed. The first wave in the summer of 1918 did lead to illness, absence from work and hospitalisations, but to a lesser extent to increased mortality. In contrast, the second, longest and strongest wave in the autumn/winter of 1918 also led to greatly increased (excess) mortality in addition to the burden of illness. The later wave in the first months of 1920 was again associated with an increase in all pandemic parameters. Furthermore, we can see that public health measures such as bans on gatherings and school closures were associated with a decrease in the course of the pandemic, while the lifting or non-compliance with these measures was associated with an increase of reported cases.

Discussion

Our study emphasizes the need to analyse a pandemic's disease burden comprehensively, beyond mortality. It highlights the importance of considering incidence, hospitalizations, and work absences as distinct but related aspects of disease impact. This approach reveals the nuanced dynamics of a pandemic, especially crucial during multi-wave outbreaks.

Source: Epidemics, https://www.sciencedirect.com/science/article/pii/S1755436525000015?via%3Dihub

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#Replication kinetics, #pathogenicity and virus-induced cellular responses of #cattle-origin #influenza A(#H5N1) isolates from #Texas, #USA

ABSTRACT

The host range of HPAIV H5N1 was recently expanded to include ruminants, particularly dairy cattle in the United States (US). Shortly after, human H5N1 infection was reported in a dairy worker in Texas following exposure to infected cattle. Herein, we rescued the cattle-origin influenza A/bovine/Texas/24-029328-02/2024(H5N1, rHPbTX) and A/Texas/37/2024(H5N1, rHPhTX) viruses, identified in dairy cattle and human, respectively, and their low pathogenic forms, rLPbTX and rLPhTX, with monobasic HA cleavage sites. Intriguingly, rHPhTX replicated more efficiently than rHPbTX in mammalian and avian cells. Still, variations in the PA and NA proteins didn’t affect their antiviral susceptibility to PA and NA inhibitors. Unlike rHPbTX and rLPbTX, both rHPhTX and rLPhTX exhibited higher pathogenicity and efficient replication in infected C57BL/6J mice. The lungs of rHPhTX-infected mice produced higher inflammatory cytokines/chemokines than rHPbTX-infected mice. Our results highlight the potential risk of HPAIV H5N1 virus adaptation in human and/or dairy cattle during the current multistate/multispecies outbreak in the US.

Source: Emerging Microbes and Infection, https://www.tandfonline.com/doi/full/10.1080/22221751.2024.2447614

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#USA, #Connecticut: Highly Pathogenic Avian #Influenza #H5N1 Detected in New London County #Backyard #Poultry Flock

(HARTFORD, CT) – Connecticut Department of Agriculture (CT DoAg) advises that Highly Pathogenic Avian Influenza (HPAI) H5N1, or bird flu, was confirmed in a backyard flock located in New London County on Wednesday, January 15, 2025. 

The backyard flock, consisting of chickens, ducks, and peacocks, were family pets, not commercial poultry, and had close contact with wild waterfowl in a nearby pond.

Samples were sent to the Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL) for testing. The results from CVMDL were then confirmed by the United States Department of Agriculture National Veterinary Services Laboratory (NVSL) in Ames, Iowa. H5N1 is highly contagious among domestic poultry, and at this time there is no effective treatment or approved vaccine for the virus in poultry. The infected flock has been depopulated to prevent spread of the disease.

“Collaboration between state and federal partners is essential in preventing the spread of highly pathogenic avian influenza in poultry and safeguarding the health of our farmworkers,” said Agriculture Commissioner Bryan P. Hurlburt. “Through a united approach we are able to swiftly identify and respond to protect our food supply and ensure the health of our communities.”

All poultry owners and producers are advised to enhance biosecurity protocols to protect their backyard and commercial poultry flocks against H5N1.

“Biosecurity is the best defense for a flock owner to protect their birds from disease,” said State Veterinarian Dr. Thamus Morgan, DVM, MPH, DACVPM. “This should be top of mind for commercial and backyard hobby owners – we must all work together – to reduce the risk.”

Biosecurity Tips

-- Poultry biosecurity materials and checklists can be found on the USDA’s Defend the Flock website. Best practices include:

- Keep wild birds and rodents out of poultry houses and coops.

- Don’t let poultry have contact with migratory waterfowl or other wild birds.

- Wash hands and boots before and after entering the poultry area.

- Buy birds from reputable sources to receive heathy birds.

- Restrict traffic onto and off your property.

- Have a written biosecurity plan in place.

Signs of H5N1 infection include sudden increase in bird deaths, sneezing, coughing, nasal discharge, watery or green diarrhea, lack of energy, poor appetite, drop in egg production, swelling around the eyes, neck, and head, and purple discoloration of wattles, combs, and legs.

Flock owners are encouraged to report anything unusual, especially sick or dead birds, to CT DoAg at 860-713-2505 or ctstate.vet@ct.gov or the USDA at 866-536-7593.

(...)

Source: Department of Agriculture, https://portal.ct.gov/doag/press-room/press-releases/2025/january/highly-pathogenic-avian-influenza-h5n1-detected-in-new-london-county-backyard-flock

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#USA, Highly Pathogenic Avian #Influenza #H5N1 Confirmed in Commercial #Poultry Flock in #Georgia, All Poultry Activities Suspended

Atlanta, Ga – Today, the Georgia Department of Agriculture and the United States Department of Agriculture’s Animal and Plant Health Inspection Service confirmed a positive case of Highly Pathogenic Avian Influenza (HPAI) in a commercial poultry operation located in Elbert County, Georgia. 

This is the first confirmed HPAI case in a commercial poultry operation in Georgia, and the fifth detection in the state of Georgia. 

As a result of this detection, effective immediately, all in-state poultry exhibitions, shows, swaps, meets, and sales are suspended until further notice.  

"For the first time since the ongoing, nationwide outbreak began in 2022, HPAI has been confirmed in a commercial poultry operation in the state of Georgia," said Georgia Agriculture Commissioner Tyler Harper. 

"This is a serious threat to Georgia’s #1 industry and the livelihoods of thousands of Georgians who make their living in our state’s poultry industry. We are working around the clock to mitigate any further spread of the disease and ensure that normal poultry activities in Georgia can resume as quickly as possible."

On Wednesday, January 15th, 2025, the producer noticed clinical signs of Avian Influenza in their flock. Samples were collected on the morning of Thursday, January 16th, 2025, and transported to the Georgia Poultry Laboratory Network (GPLN) for testing. A positive HPAI detection was confirmed by GPLN on Thursday afternoon, and further confirmed by USDA’s National Veterinary Services Laboratory on Friday, January 17th, 2025. 

The Georgia Department of Agriculture’s Emergency Management and State Agricultural Response Teams (SART) immediately deployed to the affected premises to conduct depopulation, cleaning and disinfecting, and disposal operations on Friday, January 17th, 2025.  Operations are expected to continue into the weekend. The affected premises had approximately 45,000 broiler breeders onsite at the time of detection. 

All commercial poultry operations within a 10 Kilometer (6.2 mile) radius have been placed under quarantine and will undergo surveillance testing for a period of at least two weeks. 

As a result of this detection, poultry exhibitions, shows, swaps, and sales (flea market or auction market) in the State of Georgia are suspended until further notice. Notifications will be issued when the listed activities may resume in Georgia. 

###

Date: January 17, 2025 

To: Georgia Poultry Producers 

Subject: HPAI in the United States 

From: Janemarie Hennebelle, DVM, MPVM State Veterinarian 

Effective immediately all poultry exhibitions, shows, swaps, meets, and sales (Flea Markets, Auction Markets) in the State of Georgia are suspended until further notice.

Highly Pathogenic Avian Influenza (HPAI) has been identified in commercial poultry flocks and a backyard flock in the State of Georgia alongside an increasing number of cases nationwide. Please see Commercial, Backyard, & Wildlife cases in the United States (USDA APHIS) for more information about HPAI detections in the United States. 

Poultry exhibitions, shows, swaps, meets, and sales (flea markets, auction markets) in the State of Georgia are suspended until further notice. Notifications will be announced when listed activities can resume in Georgia. 

Good biosecurity practices are the best defense against AI infection and poultry producers must take the following measures to protect their flocks: 

-- Move poultry with outside access indoors. 

-- Continue strict biosecurity practices, including a clear line of separation on the farm. 

-- Monitor flocks for clinical signs of HPAI. 

-- Birds may become quiet, not eat or drink, and have discolored combs and feet, or die suddenly with no signs of disease. 

-- Report unexplained mortality in your birds immediately. 

-- Avian Influenza (AI) is a reportable disease in Georgia. If you have concerns about AI in birds, call the Georgia Avian Influenza hotline at 770-766-6850 or visit https://www.gapoultrylab.org/avian-influenza-hotline/. 

-- Report dead wild birds when seen in unusually high numbers in a single location to DNR. Call 1-800-366-2661 or report online at https://georgiawildlife.com/report-dead-birds. 

Biosecurity and other resources: 

- GDA Avian Influenza Resource Page 

- Protect Your Flock (GDA) 

- Defend the Flock - Resource Center (USDA APHIS)

Source: Department of Agriculture, https://agr.georgia.gov/pr/highly-pathogenic-avian-influenza-confirmed-commercial-poultry-flock-georgia-all-poultry

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#USA, #USDA: APHIS Updates #Policy to Enhance #Surveillance of #Turkey #Flocks in Highly Pathogenic Avian #Influenza Affected States

WASHINGTON, January 17, 2025—As part of its ongoing, multi-faceted efforts to combat the spread of highly pathogenic avian influenza (HPAI), USDA’s Animal and Plant Health Inspection Service (APHIS) today is updating its policy for pre-slaughter surveillance to enhance testing of turkey flocks in affected states. 

In late December 2024, APHIS became aware of a genetic link between turkeys potentially infected with HPAI H5N1, virus detected in raw pet food, and an infected household cat.

Out of an abundance of caution, and to remove a potential avenue for ongoing disease spread as well as to bolster consumer and trading partner confidence, APHIS collaborated with state animal health officials and the poultry industry to update its guidance for existing pre-slaughter surveillance steps to further ensure that affected poultry does not enter the food system. APHIS will continue to report confirmed HPAI detections to the World Organisation for Animal Health and on the APHIS website (more information below).

These updates include implementing isolation with clinical monitoring and premovement testing 72 hours prior to sending to slaughter, for turkey premises outside control areas in HPAI-affected states. 

Specifically, APHIS will be piloting this enhanced pre-slaughter surveillance, starting with turkey premises greater than 500 birds in Minnesota and South Dakota, based on current and historical HPAI detections of commercial turkey premises in these states. These states were selected because of genetic linkages to virus from infected cats and because of the high percentage of cases in turkeys in those states. APHIS will continue to evaluate progress of the outbreak and may update this policy, if needed, to include additional states.

USDA consistently operates on a science-based, step-by-step approach, informed by what it learns about this virus through its everyday work and research and surveillance efforts. APHIS will continue to update its guidance for pre-slaughter surveillance schemes as USDA continues to follow the science on HPAI.

In May 2024, USDA announced the transfer of $824 million from the Commodity Credit Corporation (CCC) to APHIS to directly support H5N1 response efforts. This funding supports anticipated diagnostics; field response activities; pre-movement testing requirements; other necessary surveillance and control activities, including surveillance in wildlife; the Agricultural Research Service’s (ARS) work in developing vaccines for HPAI in cattle, turkeys, pigs, and goats; and food safety studies carried out by ARS and the Food Safety and Inspection Service (FSIS).

USDA remains confident in the safety of the food supply. FSIS, APHIS, and ARS have completed multiple studies to confirm that poultry and eggs that are properly prepared and cooked are safe to eat. Additionally, to verify the safety of the meat supply, these agencies have completed three separate beef safety studies related to avian influenza in meat from dairy cattle.

APHIS continues to work closely with state animal health officials on surveillance efforts to look for the virus in commercial, backyard, and wild birds. We also continue to encourage all bird owners to practice strong biosecurity—that means reducing opportunities for wildlife to spread the virus to their birds and preventing the spread of the virus from one premises to another. APHIS will continue to publicly post poultry detections on its dashboard. USDA also makes genetic sequences from the U.S. H5N1 clade 2.3.4.4b influenza virus available on GISAID (the Global Initiative on Sharing Avian Influenza Data) and the National Center for Biotechnology Information (NCBI) Sequence Read Archive (use search term “WGS of H5N1”).

(...)

Source: US Department of Agriculture, https://www.aphis.usda.gov/news/agency-announcements/aphis-updates-policy-enhance-surveillance-turkey-flocks-highly-pathogenic

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#USA, #FDA: #Cat and #Dog #Food #Manufacturers Required to Consider #H5N1 in Food #Safety Plans

January 17, 2025

The U.S. Food and Drug Administration has determined that it is necessary for manufacturers of cat and dog foods who are covered by the FDA Food Safety Modernization Act Preventive Controls for Animal Food (PCAF) rule and using uncooked or unpasteurized materials derived from poultry or cattle (e.g., uncooked meat, unpasteurized milk or unpasteurized eggs) to reanalyze their food safety plans to include Highly Pathogenic Avian Influenza virus (specifically H5N1) as a known or reasonably foreseeable hazard. 

Furthermore, the FDA is issuing this update to ensure that cat and dog food manufacturers are aware of information about the new H5N1 hazard associated with their pet food products, which is an additional reason that manufacturers must conduct a reanalysis of their food safety plans.

The FDA is tracking cases of H5N1 in domestic and wild cats in California, Colorado, Oregon and Washington State that are associated with eating contaminated food products. 

Scientific information is evolving, but at this time it is known that H5N1 can be transmitted to cats and dogs when they eat products from infected poultry or cattle (e.g., unpasteurized milk, uncooked meat, or unpasteurized eggs) that have not undergone a processing step that is capable of inactivating the virus, such as pasteurizing, cooking or canning. 

Cats (domestic and large felids) in particular can experience severe illness or death from infection with H5N1. Dogs can also contract H5N1, although they usually exhibit mild clinical signs and low mortality compared to cats. At present, H5N1 has not been detected in dogs in the United States, but there have been fatal cases in other countries. 

The FDA Food Safety Modernization Act Preventive Controls for Animal Food (PCAF) rule requires that certain animal food businesses develop a food safety plan. In this food safety plan, animal food businesses must identify and evaluate known or reasonably foreseeable hazards for each type of animal food manufactured, processed, packed, or held at their facility to determine whether there are any hazards requiring a preventive control. 

Businesses must identify these hazards based on experience, illness data, scientific reports, and other information. In the hazard evaluation, animal food businesses must assess the severity of the illness or injury to humans or animals if the hazard were to occur and the probability that the hazard will occur in the absence of preventive controls. The animal food industry can find guidance related to these requirements in the FDA’s Center for Veterinary Medicine’s Guidance for Industry #245, “Hazard Analysis and Risk-Based Preventive Controls for Food for Animals.”

Under the PCAF requirements, animal food businesses must conduct a reanalysis of their food safety plan when the FDA determines it is necessary to respond to new hazards and developments in scientific understanding. The FDA has determined that it is necessary for cat and dog food manufacturers covered by the PCAF rule, who are using uncooked or unpasteurized materials derived from poultry or cattle (e.g., uncooked meat, unpasteurized milk, unpasteurized eggs) in cat or dog food, to reanalyze their food safety plans to include H5N1 as a new known or reasonably foreseeable hazard. 

The reanalysis is necessary to respond to the recent domestic cat illnesses and deaths described above and to scientific data indicating that cats and dogs have become ill from consuming H5N1 virus. 

Manufacturers that implement a preventive control for the H5N1 hazard as a result of their reanalysis will be taking an important step toward protecting cat and dog health and helping to prevent spread of H5N1. Addressing H5N1 will require a concerted effort across sectors, including by government, businesses, and consumers.

Manufacturers also are required to conduct a reanalysis of their food safety plans when they become aware of new information about potential hazards associated with animal food. The FDA and the American Veterinary Medical AssociationExternal Link Disclaimer have previously published information on risks to pets from H5N1, which has been amplified in mainstream media. Some additional published references are listed below. 

As we learn more about the transmission of H5N1 in animal food, there are several practices that the FDA is encouraging pet food manufacturers and others in the supply chain to use to significantly minimize or prevent H5N1 transmission through animal food. 

These practices include seeking ingredients from flocks or herds that are healthy, and taking processing steps, such as heat treatment, that are capable of inactivating viruses. 

For example, some businesses already implement a heat treatment step that is capable of inactivating the virus as a process control. Heat treatments have been shown to be effective for inactivating H5N1 in meat, milk, and egg products. A different practice would be to implement a supply-chain-applied control to provide assurance that ingredients used in animal food do not come from H5N1-infected animals. 

To assist animal food businesses as they conduct their reanalysis, we have included a summary of current scientific literature regarding (1) the prevalence of H5N1 in cattle and poultry and their animal-derived ingredients, (2) the severity of H5N1 illness or injury in cats and dogs, and (3) the impact of processing steps on inactivating H5N1. 

The FDA and the United States Department of Agriculture (USDA) remain confident in the safety of the food supply. USDA’s Food Safety and Inspection Service, Animal and Plant Health Inspection Service, and  Agricultural Research Service (ARS) have completed multiple studies to confirm that meat, poultry and eggs that are properly prepared and cooked are safe to eat. Additionally, to verify the safety of the meat these agencies have completed three separate beef safety studies related to avian influenza in meat from dairy cattle. Furthermore, USDA and the U.S. Food and Drug Administration (FDA) have performed multiple retail sampling studies to reaffirm the safety of the pasteurized milk supply and milk products.

Source: US Food and Drugs Administration, https://www.fda.gov/animal-veterinary/cvm-updates/cat-and-dog-food-manufacturers-required-consider-h5n1-food-safety-plans

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#Italy, Avian #influenza {#H5N1}: a #cat tested positive after being in close contact with backyard #poultry

{Original Article in Italian, edited and translated}

 17/01/2025 13:28

Bologna – In Valsamoggia (Bo) a case of avian influenza was found in a cat. The animal lived in close contact with the poultry of a small family farm where the avian infection had already been identified which had led, as required by law, to the suppression of all the poultry present.

The positivity in the cat was diagnosed by the Forlì branch of the Experimental Zooprophylactic Institute of Lombardy and Emilia-Romagna and confirmed by the National Reference Center for Avian Influenza.

“Nothing new and no alarm,” commented Pierluigi Viale , professor of Infectious Diseases at the Department of Medical and Surgical Sciences at the University of Bologna and director of the Infectious Diseases Unit at the Sant’Orsola Polyclinic. 

“The circulation of avian influenza is well known. Cats are already described in scientific literature as animals quite prone to contracting the ‘bird flu’ and there have been several recorded cases of cats dying from avian influenza in the USA, Canada and Europe. But these are mostly stray cats, street cats, that live in rural areas and that can come into contact with infected organic material. A situation that therefore does not concern our domestic cats that live in the city or in apartments.”

Dr. Giovanni Tosi , director of the Zooprofilattico branch in Forlì, confirms that there are avian influenza viruses that can also adapt to mammals (including humans), but the risk of contracting the infection is very low and is linked to close and prolonged contact with infected birds. A situation that therefore does not concern domestic animals that live in the city or in apartments.

Even with regard to food safety, there is no risk associated with the consumption of poultry meat and there is no risk of infection for humans, except in conditions of close contact with infected animals.

Given the exceptional nature of the cases, Community legislation does not provide for specific control measures for cats positive for avian influenza, but for the protection of the animals themselves it is recommended that they be kept isolated under the control of the veterinary service of the ASL which carries out surveillance to evaluate the clinical progress of the disease and follow the course of the infection.

To contain the virus and prevent its spread, the veterinary service of the Bologna Local Health Authority is currently carrying out preliminary tests on blood samples and swabs on another cat that lived with the one that tested positive.

(...)

Source: Emilia-Romagna Region Government, https://notizie.regione.emilia-romagna.it/comunicati/2025/gennaio/sanita-influenza-aviaria-risultato-positivo-un-gatto-a-valsamoggia-bo-viveva-a-stretto-contatto-con-il-pollame-di-un-allevamento-familiare-risultato-infetto-attivato-subito-il-servizio-veterinario-dell2019azienda-usl-per-circoscrivere-e-impedire-la

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#Germany - #Influenza A #H5N5 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

 Wild Laridae birds in Schleswig-Holstein Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6196

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Low-Level #Zoonotic #Transmission of Clade C #MERS-CoV in #Africa: Insights from Scoping Review and Cohort Studies in #Hospital and Community Settings

Abstract

Human outbreaks of Middle East respiratory syndrome coronavirus (MERS-CoV) are more common in Middle Eastern and Asian human populations, associated with clades A and B. In Africa, where clade C is dominant in camels, human cases are minimal. We reviewed 16 studies (n = 6198) published across seven African countries between 2012 and 2024 to assess human MERS-CoV cases. We also analyzed data from four cohort studies conducted in camel-keeping communities between 2018 and 2024 involving camel keepers, camel slaughterhouse workers, and hospital patients with acute respiratory illness (ARI). The analysis showed a pooled MERS-CoV prevalence of 2.4% (IQR: 0.6, 11.4) from 16 publications and 1.14% from 4 cohort studies (n = 2353). Symptomatic cases were rarely reported, with most individuals reporting camel contact, and only 12% had travel history to the Middle East. There was one travel-associated reported death, resulting in a mortality rate of 0.013%. The findings suggest a low camel-to-human transmission of clade C MERS-CoV in Africa. Ongoing research focuses on genomic comparisons between clade C and the more virulent clades A and B, alongside the surveillance of viral evolution. This study highlights the need for continuous monitoring but indicates that MERS-CoV clade C currently poses a minimal public health threat in Africa.

Source: Viruses, https://www.mdpi.com/1999-4915/17/1/125

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#USA, #Monitoring for Avian #Influenza A(#H5) Virus In #Wastewater {Jan. 5-11 '25}

 {Excerpt}

Time Period: January 05 - January 11, 2025

-- H5 Detection: 53 sites (15.8%)

-- No Detection: 282 sites (84.2%)

-- No samples in last week: 61 sites

(...)

Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/bird-flu/h5-monitoring/index.html

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#USA, Novel #Influenza A #H5N1 Virus: One Pediatric Case in #California {FluView}

 {Excerpt}

One confirmed human infection with influenza A(H5) virus was reported to CDC this week. To date, human-to-human transmission of influenza A(H5) virus has not been identified in the United States.

This case was reported by the California Department of Public Health and occurred in a child less than 18 years old with no known contact with influenza A(H5N1) virus-infected animals or humans. The investigation into the source of infection for this case is ongoing, and no human-to-human transmission has been identified.

A specimen from the individual was tested at a public health laboratory using the CDC influenza A(H5) assay before being sent to CDC for further testing. The specimen was positive for influenza A(H5) virus using diagnostic RT-PCR at CDC. Additional analysis including genetic sequencing is underway. In response to this detection, additional case investigation and contact monitoring are being conducted by public health officials in California.

There have now been 38 total confirmed human A(H5) cases and one probable human case of A(H5) case in California. This is the second reported pediatric case in California and in the United States.

Notification to WHO of this case was initiated per International Health Regulations (IHR). More information regarding IHR can be found at http://www.who.int/topics/international_health_regulations/en/.

The CSTE position statement, which includes updated case definitions for confirmed, probable, and suspected cases is available at http://www.cste.org/resource/resmgr/position_statements_files_2023/24-ID-09_Novel_Influenza_A.pdf

An up-to-date human case summary during the outbreak by state and exposure source is available at www.cdc.gov/bird-flu/situation-summary/index.html

Information about avian influenza is available at https://www.cdc.gov/flu/avianflu/index.htm.

Interim recommendations for Prevention, Monitoring, and Public Health Investigations are available at https://www.cdc.gov/bird-flu/prevention/hpai-interim-recommendations.html.

The latest case reports on avian influenza outbreaks in wild birds, commercial poultry, backyard or hobbyist flocks, and mammals in the United States are available from the USDA at https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/2022-hpai.

(...)

Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/fluview/surveillance/2025-week-02.html

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Isoleucine at position 137 of #Hemagglutinin acts as a #Mammalian #adaptation #marker of #H9N2 Avian #influenza virus

Abstract

The H9N2 subtype of avian influenza virus (AIV) is widely distributed among poultry and wild birds and is also a threat to humans. During AIV active surveillance in Liaoning province from 2015 to 2016, we identified ten H9N2 strains exhibiting different lethality to chick embryos. Two representative strains, A/chicken/China/LN07/2016 (CKLN/07) and A/chicken/China/LN17/2016 (CKLN/17), with similar genomic background but different chick embryo lethality, were chosen to evaluate the molecular basis for this difference. A series of reassortants between CKLN/07 and CKLN/17 were generated and their chick embryo lethality was assessed. We found that the isoleucine (I) residue at position 137 (H3 numbering) in the hemagglutinin (HA) was responsible for the chick embryo lethality of the H9N2 virus. Further studies revealed that the threonine (T) to I mutation at HA position 137 enhanced viral replication in vitro and in vivo. Moreover, the HA-T137I substitution in H9N2 avian influenza virus increased the guinea pig transmission efficiency. We also found that the HA-T137I substitution was critical for α2,6-linked sialic acid binding preference and HA activation and stability of H9N2 virus. Our findings demonstrated that HA-137I is a key molecular marker for mammalian adaptation of H9N2 AIV.

Source: Emerging Microbes and Infections, https://www.tandfonline.com/doi/full/10.1080/22221751.2025.2455597

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#Antibody responses against #influenza A decline with successive years of annual influenza #vaccination

Abstract

Influenza vaccine effectiveness and immunogenicity can be compromised with repeated vaccination. We assessed immunological markers in a cohort of healthcare workers (HCW) from six public hospitals around Australia during 2020–2021. Sera were collected pre-vaccination and ~14 and ~180 days post-vaccination and assessed in haemagglutination inhibition assay against egg-grown vaccine and equivalent cell-grown viruses. Responses to vaccination were compared by the number of prior vaccinations. Baseline sera were available for 595 HCW in 2020 and 1031 in 2021. 5% had not been vaccinated during five years prior to enrolment and 55% had been vaccinated every year. Post-vaccination titres for all vaccine antigens were lowest among HCW vaccinated in all 5-prior years and highest among HCW with 0 or 1 prior vaccinations, even after adjustment. This was observed for both influenza A subtypes and was dependent on pre-vaccination titre. Expanded cohorts are needed to better understand how this translates to vaccine effectiveness.

Source: npj Vaccines, https://www.nature.com/articles/s41541-024-01057-x

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#Mongolia - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification [FINAL]

Active surveillance for avian influenza was conducted in October 2024 at Ganga Lake, located in the eastern region of Mongolia along the East Asian-Australasian Flyway for migratory birds. During the surveillance period, no clinical signs of disease or mortality were observed among wild birds. However, qRT-PCR analysis using H5-specific primers for fecal samples, followed by sequencing, confirmed the detection of the Highly Pathogenic Avian Influenza (HPAI) H5N1 subtype.

Source: WOAH, https://wahis.woah.org/#/in-review/6193

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#WHO DG's opening #remarks at the #media #briefing – 16 January 2025 {portion on avian #influenza}

 {Excerpt}

(...)

Now to the global spread of H5 avian influenza.

Last year, 66 cases of H5 were reported from the United States, plus 10 from Cambodia, 2 from Viet Nam and one each from Australia, Canada and China.

This is the highest number of reported human cases since 2015.

So far this year, 2 cases including 1 death have been reported in the United States, and 1 death in Cambodia.

Almost all these cases are associated with infected dairy cattle or poultry.

H5N1 is of particular concern because since the first human cases were reported in 2003, it has killed almost half of those it has struck.

Fortunately, H5N1 has not yet developed the ability to transmit easily between humans. But that could be only a matter of time.

Every transmission from one animal to another, or to a human, is an opportunity for the virus to mutate, or to mix with other influenza viruses.

It’s therefore imperative that the virus is not allowed to spread unchecked in animals.

WHO is working closely with the World Organisation for Animal Health and the Food and Agriculture Organization of the United Nations in a One Health approach to managing the threat of H5 globally.

We call on all countries to strengthen biosecurity on farms, testing and surveillance, and to provide personal protective equipment to farm workers who may be at risk.

We also call on all countries with outbreaks of H5 among animals to share viral samples and sequences with the WHO Global Influenza Surveillance and Response System, or GISRS.

(...)

Source: World Health Organization, https://www.who.int/news-room/speeches/item/who-director-general-s-opening-remarks-at-the-media-briefing---16-january-2025

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#Human #Infection with Avian #Influenza A(#H9N2) Virus, #Vietnam, April 2024

Abstract

In April 2024, Vietnam confirmed its first human case of influenza A(H9N2) in a 37-year-old man, marking a critical point in regional infectious disease monitoring and response. This case underscores the importance of robust surveillance systems and One Health collaboration in managing emerging zoonotic threats.

Source: Emerging Infectious Diseases Journal, https://wwwnc.cdc.gov/eid/article/31/2/24-1146_article

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#US #CDC Health #Alert Network (HAN): Advisory, Accelerated Subtyping of #Influenza A in Hospitalized Patients

Summary

The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Advisory to clinicians and laboratories due to sporadic human infections with avian influenza A(H5N1) viruses amid high levels of seasonal influenza activity. 

CDC is recommending a shortened timeline for subtyping all influenza A specimens among hospitalized patients and increasing efforts at clinical laboratories to identify non-seasonal influenza. 

Clinicians and laboratorians are reminded to test for influenza in patients with suspected influenza and, going forward, to now expedite the subtyping of influenza A-positive specimens from hospitalized patients, particularly those in an intensive care unit (ICU). This approach can help prevent delays in identifying human infections with avian influenza A(H5N1) viruses, supporting optimal patient care and timely infection control and case investigation.

Background

A panzootic of highly pathogenic avian influenza A(H5N1) viruses is currently affecting wild birds. 

In the United States, there have been outbreaks with these viruses among poultry and dairy cows, as well as infections among other animals. 

Since 2022, 67 total human cases of avian influenza A(H5) virus infection have been identified in the United States, with 66 of these cases occurring in 2024. 

Most infections in humans have been clinically mild, but one fatality has been reported. 

Many individuals infected with avian influenza A(H5) viruses have reported unprotected workplace exposures, such as handling infected or sick dairy cows or poultry without using recommended personal protective equipment. 

However, one case involved exposure to backyard poultry or wild birds. 

The source of the exposure in two confirmed cases in the United States could not be determined.

CDC has routinely recommended influenza testing for hospitalized patients with suspected influenza. 

In light of the ongoing avian influenza A(H5) virus animal outbreak in the United States, CDC now recommends subtyping of all influenza A virus-positive specimens from hospitalized patients on an accelerated basis. This accelerated subtyping is part of a comprehensive strategy to identify severe human infections with avian influenza A(H5) viruses, in addition to characterizing seasonal influenza viruses in a timely fashion.

Enhancing and expediting influenza A virus subtyping of specimens from hospitalized patients, especially from those in an ICU, can help avoid potential delays in identifying human infections with avian influenza A(H5) viruses. 

Such delays are more likely while seasonal influenza activity is high, as it is now, due to high patient volumes and general burden on healthcare facilities. 

Additional testing also ensures optimal patient care along with timely infection control. Furthermore, expediting transportation of such specimens to commercial or public health laboratories for additional testing may also accelerate public health investigation of severe A(H5) cases and sharing of information about these viruses.

Most influenza tests ordered in clinical settings do not distinguish avian influenza A(H5) viruses from seasonal influenza A viruses; a positive result simply confirms influenza A virus infection. Therefore, using tests that identify the seasonal influenza A virus subtype will help identify whether infection with a seasonal influenza A virus is present. 

If a test result is positive for influenza A virus but negative for seasonal influenza A virus subtypes [i.e., A(H1) and A(H3)], the virus detected might be a novel influenza A virus, such as influenza A(H5), and specimens should be prioritized for shipment to a public health laboratory for additional testing. 

Alternatively, there are now a few commercial laboratories offering influenza A(H5) subtyping in the clinical setting. 

Additionally, the Food and Drug Administration offers a list of influenza A typing and subtyping tests. Services like diagnostic and subtype testing that are reasonable and necessary to diagnose illness are covered in most cases by both public and private health insurers.

Subtyping is especially important in people who have a history of relevant exposure to wild or domestic animals infected or possibly infected with avian influenza A(H5N1) viruses.

CDC still considers the risk from avian influenza A(H5) viruses to the public to be low but is closely monitoring this dynamic situation. At this time, while seasonal influenza levels are high nationally, nearly all people who are currently hospitalized with influenza A virus infections probably have seasonal influenza.

Recommendations for Testing of Hospitalized Patients

In addition to jurisdiction-specific instructions for sending specimens for subtyping, CDC now recommends that all influenza A positive respiratory specimens from hospitalized patients, especially from those in an ICU, be subtyped for seasonal influenza A viruses [A(H1) and A(H3)] as soon as possible following admission—ideally within 24 hours—to support optimal patient care and proper infection prevention and control measures and to facilitate rapid public health investigation and action.

Recommendations for Clinicians

When collecting a thorough exposure history from a patient with suspected or confirmed influenza who is hospitalized, ask about potential exposure to wild and domestic animals, including pets (e.g., cats), and animal products (e.g., poultry, dairy cows, raw cow milk and raw cow milk products, raw meat-based pet food), or recent close contact with a symptomatic person with a probable or confirmed case of A(H5).

Implement appropriate infection control measures when influenza is suspected.

If avian influenza A(H5) virus infection is suspected, probable, or confirmed in a hospitalized patient, place the patient in an airborne infection isolation room with negative pressure with implementation by caregivers of standard, contact, and airborne precautions with eye protection (goggles or face shield).

Test for seasonal influenza A in hospitalized patients with suspected seasonal influenza or novel influenza A virus infection such as avian influenza A virus infection, using whatever diagnostic test is most readily available for initial diagnosis.

If the initial diagnostic test does not subtype [e.g., identify A(H1) and A(H3)], order an influenza A subtyping diagnostic test within 24 hours of hospital admission for patients who tested positive for influenza A.

Subtyping should be performed with assays available to the testing laboratory, as follows:

-- Subtyping tests should be performed in the hospital clinical laboratory, if available.

-- Alternatively, specimens should be sent to a commercial clinical laboratory.

-- If influenza A virus subtyping is not available through one of these routes, arrangements can made for influenza A virus-positive specimens to be subtyped at a public health laboratory.

Any hospitalized patients, especially those in an ICU, with suspected seasonal influenza or avian influenza A(H5) should be started on antiviral treatment with oseltamivir as soon as possible without waiting for the results of influenza testing.

Consider combination antiviral treatment for hospitalized patients with avian influenza A(H5) virus infection.

Notify the health department promptly if avian influenza A(H5N1) virus infection is suspected, probable, or confirmed in a hospitalized patient.

Questions about appropriate clinical management or testing of hospitalized patients with novel influenza A virus infection [e.g., A(H5)], including about combination antiviral treatment dosing or testing for antiviral resistance, can be directed to the CDC Influenza Division for consultation with a medical officer via the CDC Emergency Operations Center at 770-488-7100.

Recommendations for Clinical Laboratories

Subtype and send respiratory specimens that are positive for influenza A but negative for seasonal influenza A virus subtypes [i.e., negative for A(H1) and A(H3)] to a public health laboratory as soon as possible and within 24 hours of obtaining the results. Do not batch specimens for consolidated or bulk shipment to the public health laboratory if that would result in shipping delays for any such specimen.

If influenza A virus subtyping is not available at the hospital or the clinical laboratory of the treating facility, public health officials should be notified, and arrangements made for influenza A virus-positive respiratory specimens to be subtyped at a public health laboratory or a commercial laboratory with this testing capability. Specimens should be clearly linked to clinical information from the patient to ensure specimens from severely ill and ICU patients are prioritized.

Immediately contact the state, tribal, local, or territorial public health authority if a positive result for influenza A(H5) virus is obtained using a laboratory developed test (LDT) or another A(H5) subtyping test to initiate important time-critical actions.

Recommendations for Public Health Laboratories

Complete influenza A virus subtyping assays within 24 hours of receipt and report results to CDC, as required.

Recommendations for the Public

People should avoid direct contact with wild birds and other animals infected with or suspected to be infected with avian influenza A viruses.

If you must have direct or close contact with infected or potentially infected birds or other animals, wear recommended personal protective equipment (PPE).

Additional information on protecting yourself from avian influenza A(H5) infection is available from CDC.

(...)

Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/han/2025/han00520.html?ACSTrackingID=USCDC_486-DM142615&ACSTrackingLabel=HAN%20520%20-%20Health%20Advisory%20(for%20COCA%20partners)&deliveryName=USCDC_486-DM142615

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Prior #influenza virus #infection alleviates an #arbovirus #encephalitis by reducing viral titer, #inflammation, and cellular infiltrates in the central nervous system

ABSTRACT

Respiratory and encephalitic virus infections represent a significant risk to public health globally. Detailed investigations of immunological responses and disease outcomes during sequential virus infections are rare. Here, we define the impact of influenza virus infection on a subsequent virus encephalitis. We used a model system in which mice were given influenza A virus (IAV) infection 8 days prior to Semliki Forest virus (SFV) infection (IAV→SFV). IAV infection clearly attenuated the subsequent SFV infection with reduced titers of infectious SFV and lower levels of cytokines and chemokines in the central nervous system (CNS). In contrast, the SFV viremia in both IAV→SFV and SFV-only mice was comparable. Increased type I interferon (IFN) levels in the CNS after IAV infection might have contributed to some level of protection towards SFV infection in the CNS, suggesting that early control of SFV replication in the CNS during IAV→SFV infection led to reduced adaptive response, given the lower number of CD8+ T cells recruited to the brain in IAV→SFV infection. In lungs, however, prior IAV infection elicited effector CD8+ T cells with highly activated CD38 and/or CD25 phenotypes, while SFV-only infection elicited distinct effector CD8+ T cells with increased frequencies of KLRG1 expression, a hallmark of short-lived effector T cells. Taken together, our findings demonstrate that prior IAV infection can confer protective immunity toward secondary SFV infection, confirmed by reduced disease severity and inflammatory immune responses in the brain. Our work provides important insights into therapies and vaccine regimens directed against unrelated pathogens.

Source: Journal of Virology, https://journals.asm.org/doi/full/10.1128/jvi.02108-24?af=R

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#Neurotropic #Tick-Borne #Flavivirus in Alpine #Chamois (Rupicapra rupicapra rupicapra), #Austria, 2017, #Italy, 2023

Abstract

The European subtype of tick-borne encephalitis virus (TBEV-Eur; species Orthoflavivirus encephalitidis, family Flaviviridae) was the only tick-borne flavivirus present in central Europe known to cause neurologic disease in humans and several animal species. Here, we report a tick-borne flavivirus isolated from Alpine chamois (Rupicapra rupicapra rupicapra) with encephalitis and attached ticks, present over a wide area in the Alps. Cases were detected in 2017 in Salzburg, Austria, and 2023 in Lombardy and Piedmont, Italy. The virus strains exhibit 94.8–97.3% nucleotide identities to each other and are more closely related to Louping ill viruses (LIV; Orthoflavivirus loupingi; 90–92% identities) than to TBEV-Eur (less than 88%). The chamois-derived virus strains, tentatively termed “Alpine chamois encephalitis virus”, form a well-supported independent genetic clade with Spanish goat encephalitis virus, clearly separated from other LIV. This supports its designation as a new virus subtype with the proposed shared taxonomic name “Spanish goat and Alpine chamois encephalitis virus subtype” within the species Orthoflavivirus loupingi. The zoonotic potential of this newly identified virus subtype as well as its host range in other animal species including farm animals needs to be further investigated.

Source: Viruses, https://www.mdpi.com/1999-4915/17/1/122

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Immunization with a novel #RNA replicon #vaccine confers long-lasting #protection against #H5N1 avian #influenza virus in 24 #bird species

Abstract

Highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 (clade 2.3.4.4b) have spread worldwide and caused the death of hundreds of millions of wild birds and domestic poultry. Moreover, spill over of H5N1 HPAIV from infected birds to more than 50 different mammalian species including humans has been recorded. While, licensed vaccines for protection of avian or mammalian species are not yet available, a few candidate vaccines are being trialled. Here, we report on the experimental vaccination of chickens and captive wild birds using a propagation-defective vesicular stomatitis virus (VSV), in which the essential envelope glycoprotein (G) protein gene was replaced by a modified hemagglutinin gene derived from a clade 2.3.4.4b H5N1 isolated in 2022 in the animal park of Bern, Switzerland. VSV∆G(H5mb) was produced on helper cells providing the VSV G protein in trans. Specific pathogen-free (SPF) chickens that were immunized twice via the intramuscular route with adjuvant-free VSV∆G(H5mb) replicon particles induced high levels of virus-neutralizing serum antibodies and were fully protected against lethal infection by H5N1 HPAIV (clade 2.3.4.4b). Notably, immunized animals did not shed challenge virus from the respiratory or gastrointestinal tract, suggesting that herd immunity can be achieved. The same vaccine was used to immunize a total of 317 captive wild birds at Bern Animal Park and Zoo Basel, representing 24 different species. No vaccine-associated side effects were observed. Birds without previous contact to H5Nx viruses produced high to very high H5-specific neutralizing antibody titers following the second immunization, while birds showing H5-specific antibodies prior to vaccination, already developed high neutralizing antibody titers after a single immunization. One year after vaccination, most animals still showed significant neutralizing antibody titers, indicating that VSV∆G(H5mb) is able to induce a long-lasting protective immune response. Our results indicate that VSV∆G(H5mb) is an extraordinary safe and highly efficacious vaccine to stop H5N1 replication in various avian species.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.01.15.633174v1

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