#Italy, a 55-year-old man died from suspected #hemorrhagic #fever: after returning from a trip to #DRC

 {Excerpt}

He had recently returned from a trip to Congo and died on Monday evening from a suspected case of hemorrhagic fever . The victim is a 55-year-old man from Trevignano , in the province of Treviso. The news was communicated by the Public Health Hygiene Service of the Azienda Ulss 2 Marca trevigiana and diagnostic tests are underway in collaboration with the Spallanzani Institute of Rome to trace the origins of the death.

(...)

Source: Il Fatto Quotidiano (in Italian), https://www.ilfattoquotidiano.it/2024/12/17/treviso-55enne-morto-febbre-emorragica-rientrato-congo/7808209/

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Structure-based #Design of #Chimeric #Influenza #Hemagglutinins to Elicit Cross-group #Immunity

Abstract

Antigenic variability among influenza virus strains poses a significant challenge to developing broadly protective, long-lasting vaccines. Current annual vaccines target specific strains, requiring accurate prediction for effective neutralization. Despite sequence diversity across phylogenetic groups, the hemagglutinin (HA) head domain's structure remains highly conserved. Utilizing this conservation, we designed cross-group chimeric HAs that combine antigenic surfaces from distant strains. By structure-guided transplantation of receptor-binding site (RBS) residues, we displayed an H3 RBS on an H1 HA scaffold. These chimeric immunogens elicit cross-group polyclonal responses capable of neutralizing both base and distal strains. Additionally, the chimeras integrate heterotrimeric immunogens, enhancing modular vaccine design. This approach enables the inclusion of diverse strain segments to generate broad polyclonal responses. In the future, such modular immunogens may serve as tools for evaluating immunodominance and refining immunization strategies, offering potential to bridge and enhance immune responses in individuals with pre-existing immunity. This strategy holds promise for advancing universal influenza vaccine development.

Source: BioRxIV, biorxiv.org/content/10.1101/2024.12.17.628867v1?rss=1

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#Vietnam, Epidemiological #surveillance reinforced at Noi Bai #airport to prevent a #disease that appeared in the #DRC

 {Excerpt}

According to the Hanoi Center for Disease Control (CDC), in close collaboration with international health authorities, it maintains enhanced epidemiological surveillance at Noi Bai airport to quickly detect any suspected cases and implement preventive measures adapted to the evolution of the global and local health situation.

(...)

Source: Vietnam+, https://fr.vietnamplus.vn/surveillance-epidemiologique-renforcee-a-laeroport-de-noi-bai-pour-prevenir-une-maladie-apparue-en-rdc-post237120.vnp 

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#USA, #California recalls more raw #milk products due to #H5N1 #birdflu #contamination

 {Excerpt}

(Xinhua) 13:20, December 17, 2024

LOS ANGELES, Dec. 16 (Xinhua) -- The U.S. state of California has recalled raw milk produced and packaged by Valley Milk Simply Bottled, a local dairy company based in Stanislaus County, due to detection of bird flu virus.

The recall order came following the detection of Influenza-A H5N1 (bird flu) virus in samples taken from a raw milk bulk tank at the Valley Milk Simply Bottled dairy farm, said the California Department of Food and Agriculture (CDFA) in a release.

The order applies to all "Valley Milk Simply Bottled Raw Cow Milk" and "DESI Milk Raw Cow Milk" distributed in quart, half-gallon, and one-gallon plastic jugs with a code date marked on the container of DEC 23 2024 through DEC 30 2024.

CDFA urged consumers not to consume any product remaining in their refrigerators. No illnesses have been reported in the state yet.

(...)

Source: People's Daily, http://en.people.cn/n3/2024/1217/c90000-20254910.html 

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The novel #H10N3 avian #influenza virus acquired #airborne #transmission among #chickens: an increasing threat to public health

ABSTRACT

Following two human infections with the H10N3 avian influenza virus (AIV) in 2021 and 2022, a third case was discovered in Yunnan, China, in 2024, raising concerns about the potential for future pandemics. Recent studies have indicated that novel H10N3 viruses are highly pathogenic in mice and can be transmitted between guinea pigs via respiratory droplets without prior adaptation. However, the biological characteristics of novel H10N3 in poultry have not been fully elucidated. Our findings revealed that H10 subtype AIVs are predominantly prevalent in waterfowl. Notably, H10N8 and H10N3 viruses that have infected humans were primarily isolated from chickens. For the first time, double basic hemagglutinin cleavage sites (motif PEIKQGR↓GL) were identified in novel H10N3 AIVs, which exhibit enhanced replication in chickens, and can be transmitted between chickens through direct contact and respiratory droplets. Animal experimental studies demonstrated that ducks are also susceptible to H10N3 viruses and that the virus is transmissible through direct contact, suggesting a greater risk of transmission and recombination. Serological studies conducted among poultry workers suggest that while the human population was largely naïve to H10N3 infection, sporadic and undetected human infections did occur, indicating a potential increasing trend. These data further emphasize the growing threat to public health posed by zoonotic H10N3 subtype AIVs.

Source: mBio, https://journals.asm.org/doi/10.1128/mbio.02363-24

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#USA, #USDA Confirms Highly Pathogenic Avian #Influenza in Backyard Non-Poultry #Flock in #Louisiana

 {Excerpt}

WASHINGTON, December 16, 2024 – The United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed the presence of highly pathogenic avian influenza (HPAI) in a non-commercial backyard flock (non-poultry) in Bossier Parish, Louisiana.  This is the first case of HPAI in domestic birds in Louisiana during this outbreak, which began in February 2022.

Samples from the flock were tested at the Louisiana Animal Disease Diagnostic Laboratory, part of the National Animal Health Laboratory Network, and confirmed at the APHIS National Veterinary Services Laboratories in Ames, Iowa.

APHIS is working closely with state animal health officials in Louisiana on a joint incident response and will provide appropriate support as requested. 

According to the U.S. Centers for Disease Control and Prevention (CDC), the public health risk associated with these avian influenza detections in birds remains low.  As a reminder, the proper handling and cooking of all poultry and eggs to an internal temperature of 165 ˚F is recommended as a general food safety precaution.

As part of existing avian influenza response plans, Federal and State partners are working jointly on additional surveillance and testing in areas around the affected flock. The United States has the strongest AI surveillance program in the world, and USDA is working with its partners to actively look for the disease in commercial poultry operations, live bird markets and in migratory wild bird populations. 

Anyone involved with poultry production from the small backyard to the large commercial producer should review their biosecurity activities to assure the health of their birds. Visit APHIS’ Defend the Flock Resource Center for materials about biosecurity, including videos, checklists, and a toolkit.

USDA will report these findings to the World Organisation for Animal Health (WOAH) as well as international trading partners. USDA also continues to communicate with trading partners to encourage adherence to WOAH standards and minimize trade impacts. WOAH trade guidelines call on countries to base trade restrictions on sound science and, whenever possible, limit restrictions to those animals and animal products within a defined region that pose a risk of spreading disease of concern. WOAH trade guidelines also call on member countries to not impose bans on the international trade of poultry commodities in response to notifications in non-poultry.

APHIS announces the first case of HPAI in commercial and backyard flocks detected in a State but does not announce subsequent detections in the State. All cases in commercial and backyard flocks are listed on the APHIS website.

In addition to practicing good biosecurity, all bird owners should prevent contact between their birds and wild birds and report sick birds or unusual bird deaths to State/Federal officials, either through their state veterinarian or through APHIS’ toll-free number at 1-866-536-7593. APHIS urges producers to consider bringing birds indoors when possible to further prevent exposures. The Animal Health Protection Act authorizes APHIS to provide indemnity payments to producers for birds and eggs that must be depopulated during a disease response. APHIS also provides compensation for disposal activities and virus elimination activities. Additional information on biosecurity for backyard flocks can be found on APHIS’ Defend the Flock webpage.

(...)

Source: USDA, https://www.aphis.usda.gov/news/agency-announcements/usda-confirms-highly-pathogenic-avian-influenza-backyard-non-poultry-1 

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Viral #sepsis: #diagnosis, clinical #features, #pathogenesis, and #clinical considerations

Abstract

Sepsis, characterized as life-threatening organ dysfunction resulting from dysregulated host responses to infection, remains a significant challenge in clinical practice. Despite advancements in understanding host-bacterial interactions, molecular responses, and therapeutic approaches, the mortality rate associated with sepsis has consistently ranged between 10 and 16%. This elevated mortality highlights critical gaps in our comprehension of sepsis etiology. Traditionally linked to bacterial and fungal pathogens, recent outbreaks of acute viral infections, including Middle East respiratory syndrome coronavirus (MERS-CoV), influenza virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), among other regional epidemics, have underscored the role of viral pathogenesis in sepsis, particularly when critically ill patients exhibit classic symptoms indicative of sepsis. However, many cases of viral-induced sepsis are frequently underdiagnosed because standard evaluations typically exclude viral panels. Moreover, these viruses not only activate conventional pattern recognition receptors (PRRs) and retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) but also initiate primary antiviral pathways such as cyclic guanosine monophosphate adenosine monophosphate (GMP-AMP) synthase (cGAS)-stimulator of interferon genes (STING) signaling and interferon response mechanisms. Such activations lead to cellular stress, metabolic disturbances, and extensive cell damage that exacerbate tissue injury while leading to a spectrum of clinical manifestations. This complexity poses substantial challenges for the clinical management of affected cases. In this review, we elucidate the definition and diagnosis criteria for viral sepsis while synthesizing current knowledge regarding its etiology, epidemiology, and pathophysiology, molecular mechanisms involved therein as well as their impact on immune-mediated organ damage. Additionally, we discuss clinical considerations related to both existing therapies and advanced treatment interventions, aiming to enhance the comprehensive understanding surrounding viral sepsis.

Source: Military Medical Research, https://mmrjournal.biomedcentral.com/articles/10.1186/s40779-024-00581-0 

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From North to South: #Transmission #Dynamics of #H1N1pdm09 Swine #Influenza A Viruses in #Italy

Abstract

The influenza A H1N1pdm09 virus continues to be a significant pathogen, posing potential risks to both animal and human health due to its zoonotic potential. Italy, which has one of the largest swine populations in Europe, plays a crucial role in monitoring the evolution of influenza viruses in livestock. This study aims to address the existing knowledge gaps regarding the genetic diversity and transmission dynamics of H1N1pdm09 circulating in Italian swine populations. Utilizing whole genome sequencing and dynamic modeling, we conducted a comprehensive analysis of virus samples collected from swine farms across Italy. Our results reveal that multiple independent viral introductions have occurred into the country, with most cases resulting in self-limited infections and limited onward transmission. However, six distinct transmission clusters were identified, suggesting instances of sustained viral spread. These clusters were found across multiple regions of Italy, highlighting the broad geographic distribution of virus lineages. Our findings indicate that while many introductions led to localized containment, certain virus lineages were able to spread within specific regions of Italy. Through a detailed examination of selective pressures, we observed that most viral genes are under strong purifying selection in both swine and human hosts, as reflected by dN/dS ratios well below 1. The hemagglutinin (HA) gene exhibited a notably higher dN/dS ratio in swine (~0.28) compared to humans (~0.22), indicating slightly relaxed selection in swine. In contrast, other genes, such as neuraminidase (NA) and non-structural protein (NS), showed similarly strong purifying selection across both hosts. These results reflect a general trend of selective pressures affecting multiple viral components, rather than emphasizing specific genes. Our study emphasizes the importance of ongoing genomic surveillance in detecting viral circulation and mitigating risks to both animal and public health. Italy's efforts contribute significantly to global influenza monitoring and highlight the importance of a One Health approach that integrates human, animal, and environmental health. These findings provide essential data to inform public health policies and enhance preparedness against future zoonotic influenza outbreaks.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.12.12.628126v1?rss=1 

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High cumulative #viral titers of #influenza virus in #animals with significant disease #fatality rates indicate a potential trade-off between fatality and transmissibility

Abstract

Evaluating the trade-off hypothesis for the evolution of virulence using empirical data poses significant challenges. The hypothesis suggests that pathogens evolve to maximize transmissibility, but fatality imposes limits as there are diminishing gains in transmissibility. In this study, we analyzed a secondary dataset of influenza virus infections in ferrets (Mustela putorius furo), categorized by Hemagglutinin (HA) and Neuraminidase (NA) subtypes. Subgroups defined by the H7/N9 and H7/N7 combinations exhibited fatality rates of approximately 30% and reached cumulative viral titers close to 7.5 (log10 titer/mL). These levels represent intermediate fatality rates, as the H5/N6 and H5/N1 subgroups had higher fatality rates but reached lower cumulative viral titers. Using cumulative viral titer as a proxy for potential secondary transmissions, the analysis suggests that intermediate fatality rates are associated with higher numbers of secondary transmissions. However, there are significant uncertainties in subgroups with lower or no fatalities. Additionally, subgroups without fatalities showed substantial variability in cumulative viral titers.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.12.11.627227v1 

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#Sudan - #Equine #influenza virus (Inf. with) - Immediate notification

Virus untyped. Unspecified domestic equidae species in South Darfur.

Source: WOAH, https://wahis.woah.org/#/in-review/6097

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Pasteurized retail #dairy enables #genomic #surveillance of #H5N1 avian #influenza virus in #USA #cattle

Abstract

Highly pathogenic avian influenza (HPAI) viruses with H5 hemagglutinin (HA) genes (clade 2.3.4.4b) are causing an ongoing panzootic in wild birds. Circulation of these viruses is associated with spillover infections in multiple species of mammals, including a large, unprecedented outbreak in American dairy cattle. With limited testing of dairy herds, there is an unmet need for genomic surveillance. Infected cattle can shed high amounts of HPAI H5N1 viruses in milk, allowing detection in pasteurized retail dairy samples. Over a 2-month sampling period in one Midwestern city, we obtained dairy products processed in 20 different states. Here we demonstrate that a tiled-amplicon sequencing approach produced over 90% genome coverage at greater than 20x depth from 5 of 13 viral RNA positive samples. A combination of RT-qPCR testing and sequencing from retail dairy prod- ucts can be a useful component of a One Health framework for responding to the avian influenza outbreak in cattle.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2024.12.12.24318872v1

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#Influenza a Virus #Detection at the #Human – #Swine Interface in #US #Midwest Swine Farms

Abstract

This study evaluated influenza A virus (IAV) detection and genetic diversity over time, specifically at the human–swine interface in breeding and nursery farms. Active surveillance was performed monthly in five swine farms in the Midwest United States targeting the employees, the prewean piglets at sow farms, and the same cohort of piglets in downstream nurseries. In addition, information was collected at enrollment for each employee and farm to assess production management practices, IAV vaccination status, diagnostic procedures, and biosecurity. Farm employee and swine samples were screened by IAV reverse transcription real-time polymerase chain reaction (RT-rtPCR), followed by IAV subtyping RT-rtPCR and whole genome sequencing on PCR-positive samples. This study showed higher positivity of IAV RNA detection in nursery pigs compared to prewean pigs, and more whole genome sequences were also obtained in the nursery phase. Surveillance of farm employees revealed two detections of H3N2 representing the 2022–2023 human IAV season, confirming the presence of influenza in farm employees while present at work, and thus highlighting the importance of biosecurity measures at the human–swine interface. This study highlights the importance of routine active surveillance to understand the dynamics of IAV at the farm level in both farm employees and swine.

Source: Viruses, https://www.mdpi.com/1999-4915/16/12/1921

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#USA, Two more #human cases of #H5N1 #birdflu reported in #California

Two cases of bird flu have been reported in San Joaquin County, California, local health officials said.

According to a press release issued Friday and reported by the Sacramento Bee, health officials with San Joaquin County Public Health Services said both cases were farm workers who were exposed to infected animals. Both people are showing mild symptoms and are recovering, officials said, adding that there are 34 total confirmed cases across California.

In a warning posted on Facebook, health officials said bird flu was “spreading in several farms such as poultry and cattle” and urged residents to take precautions to prevent the spread of the disease.

Precautions include the use of protective equipment when handling poultry, dairy cattle or other animals that may be infected, and when handling raw and unpasteurized milk.

(...) There are currently 60 confirmed cases of bird flu in the country. While most of the cases are in California, other states with confirmed cases include Colorado, Michigan, Missouri, Oregon, Texas and Washington, according to the Centers for Disease Control and Prevention.

(...)

Source: Netizen Media, original text in Bahasa Indonesia, LINK

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Estimating the #time of Highly Pathogenic Avian #Influenza virus #introduction into #USA #poultry flocks during the 2022/24 #epizootic

Abstract

Following confirmation of the first case of the ongoing U.S. HPAI H5N1 epizootic in commercial poultry on February 8, 2022, the virus has continued to devastate the U.S. poultry sector and the pathogen has since managed to cross over to livestock and a few human cases have also been reported. Efficient outbreak management benefits greatly from timely detection and proper identification of the pathways of virus introduction and spread. In this study, we used changes in mortality rates as a proxy for HPAI incidence in a layer, broiler and turkey flock together with diagnostic test results to infer within-flock HPAI transmission dynamics. Mathematical modeling techniques, specifically the Approximate Bayesian Computation algorithm in conjunction with a stochastic within-flock HPAI transmission model were used in the analysis. The time window of HPAI virus introduction into the flock (TOI) and the adequate contact rate (ACR) were estimated. Then, using the estimated TOI together with the day when the first HPAI positive sample was collected from the flock, we calculated the most likely time to first positive sample (MTFPS) which reflects the time to HPAI detection. The estimated joint (i.e., all species combined) median of the MTFPS for different flocks was six days, the joint median most likely ACR was 6.8 newly infected birds per infectious bird per day, the joint median R0 was 13 and the joint median number of test days per flock was two. These results were also grouped by species and by epidemic phase and discussed accordingly. We conclude that this findings from this and other related studies are beneficial for the different stakeholders in outbreak management. We recommend that combining TOI analysis with complementary approaches such as phylogenetic analyses is critically important for improved understanding of disease transmission pathways. The estimated parameters can also be used to parametrize mathematical models that can guide the design of surveillance protocols, risk analyses of HPAI spread, and emergency preparedness for HPAI outbreaks.

Source: PLOS One, LINK

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#USA, First #Hawaii #Pediatric #Influenza-Associated #Death of the 2024-2025 Season Recorded

 {Excerpt}

HONOLULU — The Hawaiʻi Department of Health (DOH) announced today the first influenza-associated death in a Hawaiʻi resident under the age of 18 during this influenza, or flu season. 

This child was a Hawaiʻi County resident with underlying medical conditions. 

While specimens were not available for subtyping beyond the positive influenza result, medical and exposure history pointed to seasonal influenza as the most likely cause of illness. 

This case is not believed to be associated with the recent wastewater detection of H5 in Hilo. 

Out of respect for the family’s privacy, no further information about the child is being released.

“It is always a tragedy to lose any life, and we all feel it even more deeply when it is one of our keiki,” said DOH Director Dr. Kenneth Fink. “Seasonal influenza remains a significant health concern. If you or your loved ones have not received the flu vaccine this season, I hope you will consider doing so to help protect your ʻohana and those around you, particularly with gatherings during the holiday season.”

(...)

Source: Department of Health, LINK

#USA, Confirmed #human #H5N1 case #summary during 2024 #outbreak, by state and exposure source: 2 new cases, total = 60 (as of Dec. 13 '24)

 Source: US Centers for Disease Control and Prevention, LINK <||> 

{Excerpt}

Exposure Source

{State - Cattle - Poultry - Unknown - State Total}

1) California - 33 - 0 - 1 - 34 {+2}

2) Colorado - 1 - 9 - 0 - 10

3) Michigan - 2 - 0 - 0 - 2

4) Missouri - 0 - 0 - 1 - 1 

5) Oregon - 0 - 1 - 0 - 1 

6) Texas - 1 - 0 - 0 - 1

7) Washington - 0 - 11 - 0 - 11 

-- Source Total - 37 - 21 - 2 - 60 

NOTE: One additional case was previously detected in a poultry worker in Colorado in 2022.

Additional cases meeting the Council of State and Territorial Epidemiologists (CSTE) probable case definition have been reported by states: 1 case with dairy cow exposure (CA), 3 cases with poultry exposure (WA), and 2 cases with poultry exposure (AZ) and 1 case with no defined exposure (DE). Confirmatory testing at CDC for these cases was negative.

This table is typically updated by 5 PM EST on Mondays (for cases confirmed by CDC on Friday, Saturday, or Sunday), Wednesdays (for cases confirmed by CDC on Monday or Tuesday), and Fridays (for cases confirmed by CDC on Wednesday and Thursday). Affected states may report cases more frequently.

(...)

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#USA, LDH detects first presumptive positive #human #H5N1 case in #Louisiana

 Source: Department of Health, LINK <||>

{Excerpt}

December 13, 2024

The Louisiana Department of Health (LDH) has detected the first presumptive positive human case of highly pathogenic avian influenza (HPAI), or H5N1, in Louisiana. The individual is a resident of southwestern Louisiana and is currently hospitalized. 

LDH's Office of Public Health is coordinating with the Centers for Disease Control and Prevention (CDC) on the epidemiologic investigation. The investigation identified that the individual had exposure to sick and dead birds that are suspected to have been infected with H5N1.

H5N1 is a type of influenza virus that causes highly infectious and severe respiratory disease in birds. In the United States, outbreaks of the currently circulating H5N1 avian influenza viruses in wild birds and poultry have been ongoing since 2022. As of December 13, 2024, 60 confirmed human cases of H5N1 have been reported across the U.S., with the majority linked to exposure to infected poultry or dairy cows. There has been no human-to-human virus transmission in the U.S. to date.

While the current public health risk for the general public is low, people who work with birds, poultry or cows, or have recreational exposure to them, are at higher risk.

The best way to protect yourself and your family from H5N1 is to avoid sources of exposure. That means avoiding direct contact with wild birds and other animals infected with or suspected to be infected with bird flu viruses.

(...)

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#USA, #California: Current #H5N1 #Birdflu #Situation in #Humans: Two new cases, total now = 34

 Source: Department of Health, LINK <||>

{Excerpt}

Updated December 13, 2024​ 

* ​​The current risk to the public remains low.

* No person-to-person spread of bird flu has been detected in California.

* People rarely get bird flu, but those who interact​ with infected dairy cows, poultry, or wildlife ​have a greater risk of infection.​​

* Pasteurized milk and dairy products are safe to consume. Pasteurization inactivates the bird flu virus.​​

* CDPH is working to protect public health related to bird flu. We monitor infection data, evolving science, and the people affected. Our knowledge will change as we learn more. We are committed to reducing the impact to those at highest risk.

Human Cases in Califo​rnia​

​​​​​​​Confirmed Human Cases​: 34 {+2} 

​These numbers were last updated on December 13, 2024.

California has 1 additional probable case with dairy cow exposure that meets the  Council of State and Territorial Epidemiologists (CSTE) ​probable case definition (PDF)​. That case tested positive by a local lab and confirmatory testing at CDC was negative.​​

Confirmed human case summary during the 2024 outbreak, by exposure source.

* ​Cattle​​​​: 33

* ​Poultry: ​0

* ​Unkn​own: ​1

* ​Total: ​34

(...)

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#Estimates of #epidemiological #parameters for #H5N1 #influenza in #humans: a rapid review

 Source: MedRxIV, LINK <||> 

Abstract

Background 

The ongoing H5N1 panzootic in mammals has amplified zoonotic pathways to facilitate human infection. Characterising key epidemiological parameters for H5N1 is critical should this become widespread. 

Aim 

To identify and estimate critical epidemiological parameters for H5N1 from past and current outbreaks, and to compare their characteristics with human influenza subtypes. 

Methods 

We searched PubMed, Embase, and Cochrane Library for systematic reviews reporting parameter estimates from primary data or meta-analyses. To address gaps, we searched Google Scholar for studies of any design providing relevant estimates. We estimated the basic reproduction number for the outbreak in the US and estimated the serial interval using data from previous household clusters in Indonesia. We also applied a branching process model to simulate transmission chain size and duration to assess if simulated transmission patterns align with observed dynamics. 

Results 

From 32 studies, we identified H5N1s epidemiological profile as having lower transmissibility (R0 < 0.2) but higher severity compared to human subtypes. Evidence suggests H5N1 has longer incubation (~4 days vs ~2 days) and serial intervals (~6 days vs ~3 days) than human subtypes, impacting transmission dynamics. Key gaps remain regarding latent and infectious periods. 

Conclusions 

We characterised critical epidemiological parameters for H5N1 infection. The current U.S. outbreak shows lower pathogenicity but similar transmissibility compared to prior outbreaks. Longer incubation and serial intervals may enhance contact tracing feasibility. These estimates offer a baseline for monitoring changes in H5N1 epidemiology.

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#USA, #CDC: Novel #Influenza A Virus Cases Report, as of Dec. 13 '24

 Source: US Centers for Disease Control and Prevention, LINK <||>

{Excerpt}

Two probable cases of influenza A(H5) virus infection were reported to CDC this week by the Arizona Department of Health Services. To date, human-to-human transmission of influenza A(H5) virus has not been identified in the United States.

These cases occurred among two adult workers, ≥ 18 years of age, performing depopulation activities at a commercial poultry facility where highly pathogenic avian influenza (HPAI) A(H5N1) virus had been detected. While being monitored by local public health, these patients developed illness during the weeks ending November 23 and November 30, respectively. Both patients reported respiratory symptoms. One patient also reported conjunctivitis.

Specimens were collected from the patients and initially tested positive with high CT values at public health laboratories using the CDC influenza A(H5) assay. The specimens were negative for influenza A(H5) virus using diagnostic RT-PCR at CDC. These two probable cases are the first reported human influenza A(H5) cases reported in Arizona. 

No additional notification to WHO of these probable cases is required 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 2024 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.

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