#Surveillance and #Coinfection Dynamics of Infectious Bronchitis Virus and Avian #Influenza #H9N2 in Moroccan Broiler Farms (2021–2023): Phylogenetic Insights and Impact on Poultry Health

Abstract

Infectious bronchitis virus (IBV) and low-pathogenic avian influenza virus (LPAIV) H9N2 are commonly identified in poultry, individually or in association with other pathogens. This study monitored 183 broiler farms affected by respiratory diseases across seven regions of Morocco from January 2021 to December 2023. Among these farms, 87.98% were vaccinated against IBV, while 57.92% were against AI H9N2. Abnormally high mortality rates were observed in 44.26% of the farms, with 24.69% of cases attributed to IBV, 50.62% to LPAI H9N2, and 13.58% due to coinfection with both IBV and H9N2. RT-PCR analysis of tissue samples and cloacal and tracheal swabs collected from 183 broiler farms revealed that 33.33% were positive for IBV and 34.97% for H9N2. Coinfection by IBV and H9N2 was detected in 12.57% of cases, peaking at 17% in 2022. Co-infected flocks exhibited severe clinical signs and lesions, such as reduced food consumption, diarrhea, and renal issues. The predominant lesions were in the respiratory tract, affecting 91.26% of infected broilers. Additionally, among the 183 flocks, 50 farms that tested positive for IBV infection were randomly selected from the seven regions of Morocco for further investigation of other respiratory pathogens, including Mycoplasma gallisepticum (MG), Mycoplasma synoviae (MS), and infectious laryngotracheitis (ILT), using real-time RT-PCR. Detection rates for these pathogens were 26% for MG, 30% for MS, 4% for ILTv (vaccine strain), and 18% for ILTw (wild strain). Detection rates for single, dual, triple, and quadruple infections were 34%, 42%, 18%, and 4%, respectively. The most common dual and triple coinfections were IBV + H9N2 (14%) and IBV + MG + MS (10%). Phylogenetic analysis of the S gene identified two main IBV genotypes, namely, 793B and D181, with the latter being a strain circulating for the first time in Moroccan poultry. This underscores the urgent need to establish surveillance systems to track pathogen circulation and implement strategies to control virus spread, ensuring the protection of animals and public health.

Source: Viruses, https://www.mdpi.com/1999-4915/17/6/786

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#Anthrax - #Thailand (#WHO, D.O.N., May 29 '25)

 

{Summary}

Situation at a glance

In early May 2025, the International Health Regulations National Focal Point (IHR NFP) for Thailand notified WHO of four cases of cutaneous anthrax. 

One of the affected individuals died as a result of disease complications, while the remaining three cases were hospitalized and received appropriate medical care. 

All reported cases had direct contact with cattle suspected to be infected with anthrax. 

A rapid field investigation and response was conducted by the national health authorities. 

All potentially exposed individuals were identified, and all high-risk contacts received post-exposure prophylaxis. 

On 28 May, an additional case was announced who was associated with the slaughtering of cattle. 

Disease control measures, including animal quarantine, and vaccination campaign targeting cattle withing five km radius, public awareness campaigns, and enhanced surveillance, were implemented in the affected area. 

Anthrax is a life-threatening zoonotic disease caused by the spore-forming bacterium Bacillus anthracis. 

Humans can get anthrax from infected animals or contaminated animal products. 

It generally does not spread between people. 

Currently, due to the robust public health measures implemented by Thailand, the risk of international disease spread through animal movement remains low.

(...)

Source: World Health Organization, https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON573

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#Update on the #Epidemiology of Middle East Respiratory Syndrome {#MERS} #Coronavirus — #Worldwide, 2017–2023 (US CDC, MMWR)

 

Summary

-- What is already known about this topic?

- Middle East respiratory syndrome (MERS) coronavirus (MERS-CoV) is a zoonotic virus transmitted sporadically from camels to humans, with limited subsequent human-to-human transmission. Most reported human cases of MERS have occurred in or near the Arabian Peninsula. Standardized clinical and epidemiologic criteria are used to determine who in the United States should be tested for MERS-CoV. In the United States, the last identified and confirmed MERS cases occurred in 2014.

-- What is added by this report?

- Global reported MERS cases have declined substantially since the COVID-19 pandemic. Numbers of travelers entering the United States from in or near the Arabian Peninsula declined during the COVID-19 pandemic, but now have returned to prepandemic levels. U.S. MERS-CoV testing declined during 2017–2023 and remains low relative to prepandemic years. Clinical and epidemiologic criteria to guide U.S. testing were updated in 2024.

-- What are the implications for public health practice?

- Though global reported MERS cases have declined substantially, continued MERS-CoV surveillance is important to maintaining MERS preparedness and response capabilities.

Abstract

Middle East respiratory syndrome coronavirus (MERS-CoV) is a zoonotic virus transmitted sporadically from camels to humans. Most reported human Middle East respiratory syndrome (MERS) cases have occurred in or near the Arabian Peninsula. Limited human-to-human transmission can occur after close contact and has resulted in health care–associated outbreaks. Global reported MERS cases, U.S. testing data, and data on incoming U.S. travelers originating in and near the Arabian Peninsula during 2017–2023 were analyzed to guide U.S. MERS preparedness. Global MERS cases reported to the World Health Organization declined during the COVID-19 pandemic and remain substantially lower than during years preceding the pandemic. U.S. MERS-CoV testing numbers also declined and remain low relative to the prepandemic period. Although the number of travelers coming to the United States from in or near the Arabian Peninsula declined during the pandemic, incoming traveler volume returned to prepandemic levels. Further investigations are needed to determine whether the decline in global MERS cases reflects a true decrease in the number of infections, underascertainment of cases, or a combination. U.S. MERS persons under investigation criteria, standard clinical and epidemiologic characteristics used to guide who in the U.S. is tested for MERS-CoV, were updated in 2024 and can be used to guide clinicians and jurisdictional public health partners when considering MERS-CoV testing. Continued and targeted MERS-CoV material surveillance is important to maintaining preparedness and promptly responding to potential MERS cases.

Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/mmwr/volumes/74/wr/mm7419a1.htm?s_cid=mm7419a1_e&ACSTrackingID=USCDC_921-DM147411&ACSTrackingLabel=This%20Week%20in%20MMWR%3A%20Vol.%2074%2C%20May%2029%2C%202025&deliveryName=USCDC_921-DM147411

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Altered germinal center responses in mice vaccinated with highly pathogenic avian #influenza A(#H5N1) virus

Highlights

• Different immune responses in mice vaccinated with influenza A(H5N1) than with other subtypes.

• Highly pathogenic avian influenza A(H5N1)-vaccinated mice had altered germinal center responses.

• A(H5N1)-vaccinated mice had fewer dLN germinal centers and more extrafollicular B cells.

• A(H5N1)-vaccinated mice had more dLN follicular helper and regulatory T cells.

• Our study represents a timely assessment of A(H5N1) risk to human health.

Abstract

Highly pathogenic avian influenza (HPAI) H5N1 virus vaccines typically yield lower neutralizing antibody titers in animals than influenza A virus (IAV) vaccines derived from other viral subtypes. To understand these differences, we compared the cellular immune responses in the draining lymph nodes (dLNs) of mice vaccinated with an inactivated whole H5N1 vaccine to those in mice vaccinated with seasonal H1N1pdm09, H7N9, or H9N2 IAV vaccines. H5N1-vaccinated mice exhibited reduced serum neutralizing antibody titers, despite the hemagglutinin-binding immunoglobulin production being similar to that with other IAV vaccines. Although bulk RNA sequencing showed no differences in B-cell populations after H5N1 and H1N1pdm09 vaccination, H5N1 vaccination resulted in fewer, but larger, dLN germinal centers and significantly more extrafollicular B cells, which are known to produce lower neutralizing antibody titers. Furthermore, H5N1-vaccinated mice had significantly more follicular helper and regulatory T cells. Therefore, differences in neutralizing antibody production in mice after IAV vaccination correlate with subtype-dependent germinal center reactions in the dLNs.

Source: Vaccine, https://www.sciencedirect.com/science/article/pii/S0264410X25006085?via%3Dihub

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Stability of #influenza viruses in the #milk of #cows and #sheep

Abstract

In late 2023, H5N1 high pathogenicity avian influenza (HPAIV) started circulating in dairy cattle in the USA. High viral titres were detected in milk from infected cows, raising concerns about onwards human infections. Although pasteurisation was shown to effectively inactivate influenza viruses in milk, unpasteurised milk still poses a risk of infection, both from occupational exposure in dairies and from the consumption of raw milk. We therefore assessed how long influenza viruses could remain infectious for in milk without heat inactivation. We examined the stability of a panel of influenza viruses in milk, including a contemporary H5N1 HPAIV and a variety of other influenza A and D viruses. We incubated viruses in cows' milk under laboratory conditions: at room temperature to simulate exposure in dairies and at 4°C to simulate exposure to refrigerated raw milk. Following an isolated report of H5N1 viral RNA being detected in milk from a sheep in the UK, we also carried out similar experiments with a laboratory strain of IAV in sheep's milk. Although the survival of influenza viruses in milk was variable, we consistently found that under laboratory conditions substantial viral infectivity remained over periods when people might reasonably be exposed to infected milk - for over a day at room temperature and for more than 7 days when refrigerated. Our results highlight the zoonotic risk of H5N1 HPAIV in raw milk from infected animals and reinforce the importance of taking measures to mitigate this risk.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2025.05.28.25328508v1

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G57 #genotype of BJ/94-like #H9N2 lineage exhibits increased #replication & virulence in chickens compared to G1 Middle East Group B lineage

Abstract

Avian influenza H9N2 viruses cause significant economic losses to the poultry industry and pose a public health risk due to their potential to reassort with other avian influenza viruses, generating strains with zoonotic and pandemic potential. Two major H9N2 lineages dominate globally: the G1 lineage (genotype G1-B), prevalent in the Middle East, Africa and the Indian subcontinent, and the BJ/94 lineage (predominantly genotype G57), dominant in China, Vietnam, South Korea, Indonesia, and the Far East. We investigated replication, transmission, and pathogenicity of representatives of these two lineages, linking genotype to phenotype. The G57 strain A/Ck/Vietnam/H7F-14-BN4-315/2014 (Vietnam/315) was more lethal to chicken embryos than the G1-B strain A/chicken/Pakistan/UDL-01/2008 (Pakistan/UDL-01). Vietnam/315 exhibited higher replication in both directly infected and contact chickens, with increased virus shedding from the oropharynx and cloaca. In contrast, Pakistan/UDL-01 virus was primarily shed from the oropharynx, highlighting differences in replication, tissue tropism and transmission. Gene analysis showed the M gene of Vietnam/315 enhanced replication in primary chicken kidney cells, whereas the PB2, HA, NA, and M genes promoted increased replication in Madin-Darby Canine Kidney cells. Both viruses showed preferential binding to avian-like receptors over human-like receptors. However, Vietnam/315, however, exhibited higher neuraminidase activity and a more acid-stable HA (pH fusion 5.2) than Pakistan/UDL-01 virus. These findings suggest G57 genotype viruses possess greater replication and transmission fitness than G1-B viruses in vivo, ex vivo and in vitro. Reassortment events involving G1-B strains acquiring G57 genes may enhance replication and virulence, potentially increasing the risk of animal and human infection.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.05.28.656345v1

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Post-mortem #investigation of role of endemic #human #coronaviruses in causal pathway to death amongst #children under 5 in LMIC: findings from the Child Health & Mortality Prevention Surveillance

Highlights

• Large study on the contribution of HCoV to childhood deaths

• Supports vigilance or further investigations into HCoV pathogenesis

• Potential information for the role Covid-19 will play during severe childhood disease

• Highlights the importance of polymicrobial infection during severe disease episodes

Abstract

Background

Endemic human coronaviruses (HCoV-229E, HKU1, NL63, and OC43) are common causes of mild or asymptomatic respiratory infections in children but are considered rare causes of death.

Methods

We evaluated paediatric deaths from January 2017 through December 2022. A panel of experts determined the cause of death (CoD) by reviewing available data, including pathological and molecular findings from minimally invasive tissue sampling (lung tissues, blood, CSF, and nasopharyngeal swabs), clinical records, and verbal autopsies.

Results

Endemic HCoV were detected in the respiratory samples of 3% (n=86/3357) of enrolled decedents: 1% (n=12/2043) of neonates, 5%(n=35/681) of infants and 6% (n=39/633) of children deaths. However, HCoVs were attributed as the CoD in only two cases — both involving young infants with underlying birth defects and severe wasting, who succumbed to polymicrobial hospital-acquired infections involving HCoV-OC43, Klebsiella pneumoniae, and Acinetobacter baumannii. Amongst the remaining 84 decedents in whom an HCoV was detected, 82% (n=69/84; median Ct of 25.34; range:15.28-36.17) were deaths attributed to other infections, including 54% (n=32/69; median Ct of 23.86; range:15.28-35.2) with lower respiratory infections determined to be the CoD. The bulk of these deaths (96%,n=66/69) were attributed to other pathogens - Plasmodium falciparum (27%,n=19/69), K.pneumoniae (23%,n=16/69), Streptococcus pneumoniae (20%,n=14/69), Escherichia coli (16%,n=11/69) and Cytomegalovirus (10%,n=7/69).

Conclusion

Although endemic HCoV was identified in children who died of respiratory infections, it was rarely attributed to being in the CoD. Nevertheless, further research is warranted to explore the potential role of HCoVs in LRTI pathogenesis and their impact on facilitating more pathogenic infections.

Source: Journal of Clinical Virology, https://www.sciencedirect.com/science/article/abs/pii/S1386653225000460?dgcid=rss_sd_all

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hnRNPM regulates #influenza A virus #replication through distinct mechanisms in #human and #avian cells: implications for cross-species transmission

ABSTRACT

The eight-segmented RNA genome of influenza A virus (IAV) is transcribed and spliced into 10 major viral mRNAs in the nucleus of infected cells. Both transcription and splicing are facilitated by the host RNA polymerase II (Pol II) machinery via interactions between the viral ribonucleoprotein (vRNP) complex and various host factors. In this study, we demonstrate that IAV vRNPs recruit species-specific heterogeneous nuclear ribonucleoprotein M (hnRNPM) to support their replication in human and avian cells through distinct mechanisms. In A549 cells, human hnRNPM specifically facilitates the efficient transcription of HA, NA, M, and NS segments of WSN virus in a gene coding sequence-dependent manner. In contrast, in DF-1 cells, chicken hnRNPM restricts excessive splicing of M segment mRNA to ensure proper M2 protein production. Notably, human hnRNPM, with 34 additional amino acids compared with its chicken counterpart, fails to inhibit the M2 expression in DF-1 cells, whereas both human and chicken hnRNPM regulate WSN virus replication similarly in A549 cells. These findings highlight the host-specific roles of M2 levels in IAV replication and reveal how IAV co-opts host factors through virus genome sequence-dependent and host species-specific mechanisms, underscoring its high flexibility and adaptability during cross-species transmission.

Source: Journal of Virology, https://journals.asm.org/doi/full/10.1128/jvi.00067-25?af=R

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Genomic and #Clinical #Analysis of a #Fatal Human #Lyssavirus irkut Case: Evidence for a Natural Focus in the Russian Far East

Abstract

In this report, we document and analyze a case in which the Irkut virus (IRKV) (Mononegavirales: Rhabdoviridae) caused a fatal human case following a bat bite in June 2021. Unfortunately, the available data did not permit a detailed taxonomic classification of the carrier bat (Chiroptera). The event occurred in the southwestern part of the Sikhote-Alin mountain region (Russian Far East) covered by the Ussuri taiga forest. The symptoms of the illness began with the following: fever; pronounced psychomotor and motor agitation; tremor of the lower jaw and tongue; aphasia; dyslexia; and dysphagia. These rapidly developed, leading to a severe and fatal encephalitis. The patient was not vaccinated for rabies and did not receive rabies immunoglobulin. Using brain sections prepared from the deceased, molecular diagnostics were performed: immunofluorescence (polyclonal anti-rabies immunoglobulin) indicating the presence of the lyssavirus antigen; and RT-PCR indicating traces of viral RNA. Sectional material (brain) was used for whole-genome sequencing, resulting in a near-complete sequence of the lyssavirus genome. The obtained genomic sequence was identified as the Irkut virus. A comparative analysis of the new sequence and other currently available IRKV sequences (NCBI) revealed differences. Specifically, amino acid differences between antigenic sites in the isolate and those of the rabies vaccine strain used regionally were noted. The patient history and subsequent analysis confirm human IRKV infection following bat contact. Like other fatal cases of IRKV infection described earlier, this case occurred in the southern part of the Russian Far East. Two have occurred in the southwestern part of the Sikhote-Alin mountain region. This indicates the possible existence of an active, natural viral focus.

Source: Viruses, https://www.mdpi.com/1999-4915/17/6/769

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#COVID19 - Global #Situation (#WHO, D.O.N., June 28 '25)

 

Situation at a glance

Since mid-February 2025, according to data available from sentinel sites, global SARS-CoV-2 activity has been increasing, with the test positivity rate reaching 11%, levels that have not been observed since July 2024. 

This rise is primarily observed in countries in the Eastern Mediterranean, South-East Asia, and Western Pacific regions. 

Since early 2025, global SARS-CoV-2 variant trends have slightly shifted. Circulation of LP.8.1 has been declining, and reporting of NB.1.8.1, a Variant Under Monitoring (VUM), is increasing, reaching 10.7% of global sequences reported as of mid-May. 

Recent increases in SARS-CoV-2 activity are broadly consistent with levels observed during the same period last year, however, there still lacks a clear seasonality in SARS-CoV-2 circulation, and surveillance is limited. 

Continued monitoring is essential. WHO advises all Member States to continue applying a risk-based, integrated approach to managing COVID-19 as outlined in the Director-General’s Standing Recommendations [1]. 

As part of comprehensive COVID-19 control programmes, vaccination remains a key intervention for preventing severe disease and death from COVID-19, particularly among at risk groups.

Description of the situation

There has been an increase in SARS-CoV-2 activity globally, based on SARS-CoV-2 data reported to the Global Influenza Surveillance and Response System (GISRS) from sentinel surveillance sites. 

As of 11 May 2025, the test positivity rate is 11% across 73 reporting countries, areas and territories. This level matches the peak observed in July 2024 (12% from 99 countries) and marks a rise from 2% reported by 110 countries back in mid-February 2025 (Figure 1). 

The increase in test positivity rate is mainly being driven by countries in the Eastern Mediterranean Region, the South-East Asia Region, and the Western Pacific Region. 

Countries in the African Region, European Region, and the Region of the Americas are currently reporting low levels of SARS-CoV-2 activity with percent positivity from sentinel or systematic virological surveillance sites ranging from 2% to 3%. 

However, some areas—particularly in the Caribbean and Andean subregions in the Region of the Americas showed increasing trends of SARS-CoV-2 test positivity as of 11 May. 

Publicly available wastewater monitoring data from countries in the European Region and the Northern America subregion remain low and, at present, do not indicate any upward trend in SARS-CoV-2 activity as of 11 May 2025.

The reporting of COVID-19 associated hospitalizations, Intensive Care Unit (ICU) admissions, and deaths is very limited from the countries in the Eastern Mediterranean Region, the South-East Asia Region, and the Western Pacific Region and does not allow for evaluation of the impact on health systems by WHO. 

(...)

SARS-CoV-2 Variant Evolution and Circulation

SARS-CoV-2 continues to evolve, and between January and May 2025, there were shifts in global SARS-CoV-2 variant dynamics. 

At the beginning of the year, the most prevalent variant tracked by WHO at the global level was XEC, followed by KP.3.1.1. 

In February, circulation of XEC began to decline while that of LP.8.1 increased, with the latter becoming the most detected variant in mid-March. 

Since mid-April, the circulation of LP.8.1 has been slightly declining as NB.1.8.1 is increasingly being detected.

(...)

The most recently designated variant under monitoring (VUM) is NB.1.8.1, which is a descendent lineage of XDV.1.5.1, in turn a descendent of JN.1, with the earliest sample collected on 22 January 2025. 

In comparison to the currently dominant SARS-CoV-2 variant, LP.8.1, NB.1.8.1 has the following additional spike mutations: T22N, F59S, G184S, A435S, V445H, and T478I. 

Spike mutations at position 445 have been shown to enhance binding affinity to hACE2 receptor, which could increase the variant’s transmissibility; mutations at position 435 have been shown to modestly reduce the neutralization potency of class 1 and class 1/4 antibodies; mutations at position 478 have been shown to enhance the evasion of Class 1/2 antibodies.[2]

As of 18 May 2025, 518 NB.1.8.1 sequences were submitted to GISAID from 22 countries, representing 10.7% of the globally available sequences in epidemiological week (EW) 17 of 2025 (21 to 27 April 2025). 

While the percentage remains low, this presents a significant rise from 2.5% four weeks prior in EW14 of 2025 (31 March to 6 April 2025). 

Between EW14 and EW17 of 2025, increased circulation of NB.1.8.1 was detected in all three WHO regions that are consistently sharing SARS-CoV-2 sequences, i.e. from 8.9% to 11.7% for the Western Pacific region, from 1.6% to 4.9% for the region of the Americas, and from 1.0% to 6.0% for the European region. 

There are only 5 NB.1.8.1 sequences from the South-East Asia Region, and none from the African Region or the Eastern Mediterranean Region.

COVID-19 Vaccination Update

From the latest available global data covering the period between 1 January and 30 September 2024, overall COVID-19 vaccine uptake among high-risk groups remains low, with significant disparities across regions and income levels. 

Among older adults[3], just 1.68% were reported as having received a dose so far in 2024 up to 30 September 2024 across 75 reporting Member States, and among health and care workers, uptake stood at 0.96% across 54 reporting Member States. 

An estimated 39.2 million individuals, across 90 reporting Member States covering 31% of the global population, had received a dose in 2024 through 30 September 2024, including 14.8 million in the third quarter. 

Uptake was notably higher in the Region of the Americas and the European Region, with older adult coverage reaching 5.1% in the European Region and 3.6% in the Region of the Americas compared to less than 0.5% in other regions. 

A similar disparity was observed when comparing countries by income level. High and upper middle-income countries (HIC/UMIC) reported higher vaccine uptake among older adults with 4.3% and 1.2% respectively, compared to less than 0.5% in low-income countries (LIC) and lower middle-income countries (LMIC). 

Similar patterns were seen among health and care workers, with uptake in the Region of the Americas (2.8%) far exceeding the less than 0.5% seen in other regions. 

Among income groups, UMICs reported 2.1% coverage, compared to just 0.3% in LICs and 0.1% in LMICs. Complete vaccination data for 2024 is being collected now and will be released in mid-July 2025.

Currently approved COVID-19 vaccines continue to provide protection against severe disease and death. 

To ensure approved vaccines remain effective, the WHO Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC) continues to monitor and review the impact of SARS-CoV-2 evolution on the performance of available vaccines.  

In May 2025, TAG-CO-VAC advised that monovalent vaccines targeting the JN.1 or KP.2 lineages remain appropriate. They also noted that vaccines targeting the LP.8.1 lineage can be considered as a suitable alternative. 

Vaccination should not be delayed. However, in anticipation of access to latest variant-containing vaccines, there is a greater benefit in ensuring that persons at high risk of developing severe COVID-19 receive a dose of any available vaccine as compared to delaying vaccination.

Overview of selected WHO regions

Eastern Mediterranean Region

In the Eastern Mediterranean Region, sentinel surveillance data have been reported from 12 countries via test positivity rates from sentinel sites in 2025. 

The test positivity rate increased from 4% in EW13 to 17% in EW17 and then declined to 15% in EW19. 

Following lower circulation in the first ten weeks of 2025, a sharp upward trend surpassed the levels of last year (11% in EW17 2024). 

Across the region, recent reports of increases in circulation have been observed in five countries to date, including Egypt, Kuwait, Oman, Saudi Arabia, United Arab Emirates and Pakistan. 

(...)

South-East Asia Region

In the South-East Asia Region, sentinel surveillance data have been reported by eight countries in 2025. 

Since the beginning of April, the test positivity rate increased from 0.5% in EW15 to 5% in EW19. 

Although at a lower level, a similar upward trend was observed during the same period in 2024, with rates rising from 4% in EW15 to 6% in EW19, and further to 10% by EW24. 

The recent increases are observed in the Maldives and Thailand. As per published national reports, a rise in COVID-19 case detections was observed in India [4] in EW20 and Thailand [5] between EW16 to EW20.

(...)

Western Pacific Region

In the Western Pacific Region, sentinel surveillance data have been reported by ten countries and areas via test positivity rates from sentinel sites in 2025. 

In the past month, the test positivity rate increased from 5% in EW14 to 11% in EW19. 

Following lower circulation in the first ten weeks of the year, a sharp upwards trend reached similar levels as last year (10% in EW18 2024). 

The recent increases have been observed in four countries and areas to date: Cambodia, China, Hong Kong SAR and Singapore.  

(...)

Public health response

Since the formal ending of the public health emergency of international concern (PHEIC) in May 2023, Member States have adopted diverse approaches to sustaining COVID-19 and broader coronavirus disease threat management. 

While some countries have integrated COVID-19 activities into existing respiratory disease programmes, others remain in transitional phases, maintaining targeted vertical interventions while adapting systems and structures for integrated management of infectious diseases. This variation reflects differing national contexts, resource availability, health system capacities and other national priorities.

Routine public health measures for COVID-19 are increasingly being embedded within broader surveillance and response systems. 

Countries have been moving to operate integrated respiratory disease surveillance platforms – such as eGISRS and Coronavirus Network (CoViNet) – which include sentinel surveillance, virological characterization and wastewater monitoring, enabling the detection of circulating SARS-CoV-2 variants and providing insight into broader trends in viral respiratory illness. 

Clinical pathways developed during the acute phase of the COVID-19 pandemic are being refined and sustained, supporting access to diagnosis, treatment, and care for individuals with COVID-19 and post-COVID-19 (long COVID) condition. 

Vaccination efforts remain a cornerstone of protection for high-risk groups, with updated vaccines being offered through routine or targeted immunization strategies, often alongside those for seasonal influenza and respiratory syncytial virus (RSV). 

Risk communication and community engagement activities continue to inform and empower the public, adapted to local contexts and evolving levels of perceived risk.

However, the long-term sustainability of these activities and the financing to support this remain a challenge in many countries. 

Health systems face an increasing number of competing priorities, including other infectious disease threats, the growing burden of non-communicable diseases, health workforce strain, and the persistent need to recover essential services disrupted during the pandemic. 

Beyond the health sector, broader societal and economic pressure, such as inflation, political instability, and humanitarian crises, further complicate efforts to maintain COVID-19 disease threat management at scale. 

WHO and partners continue to support countries in navigating these realities by promoting context-sensitive integration, prioritization, and long-term investment in respiratory disease threat management systems.

WHO continues to support Member States by convening and coordinating global stakeholders and relevant networks, developing evidence-based guidance and policy recommendations, and providing tailored support to assist Member States in building and sustaining core capabilities, in collaboration with other key partners.

WHO risk assessment

As per the latest WHO global risk assessment, covering the period July-December 2024, the global public health risk associated with COVID-19 remains high. 

There has been evidence of decreasing impact on human health throughout 2023 and 2024 compared to 2020-2023, driven mainly by: 

-- 1) high levels of population immunity, achieved through infection, vaccination, or both; 

-- 2) similar virulence of currently circulating JN.1 sublineages of the SARS-CoV-2 virus as compared with previously circulating Omicron sublineages; and 

-- 3) the availability of diagnostic tests and improved clinical case management. 

SARS-CoV-2 circulation nevertheless continues at considerable levels in many areas, as indicated in regional trends, without any established seasonality and with unpredictable evolutionary patterns. WHO produces global COVID-19 risk assessments every six months; the global risk assessment covering the period January-June 2025 is currently under development. 

WHO continues to monitor emerging SARS-CoV-2 variants and undertakes risk evaluation for designated variants of interest (VOI) and VUMs with the support of the Technical Advisory Group of Virus Evolution (TAG-VE). Evaluation of the currently predominant VUM, LP.8.1, and the most recently designated VUM, NB.1.8.1, suggests no increased public health risk posed by these variants compared to other circulating variants. 

To permit robust COVID-19 risk assessment and management, WHO reiterates its recommendations to Member States to continue to monitor and report SARS-CoV-2 activity and burden, public health and healthcare system impacts of COVID-19, strengthen genomic sequencing capacity and reporting, in particular information on SARS-CoV-2 variants [6], promptly and transparently to support global public health efforts.

WHO advice

WHO advises all Member States to continue applying a risk-based, integrated approach to managing COVID-19, embedded within broader disease prevention and control programmes, in particular those for other respiratory disease threats, in line with the WHO Director-General’s Standing Recommendations. 

Sustained investment in core public health capabilities, notably collaborative surveillance, community protection, clinical care, access to and delivery of medical countermeasures, and coordination, is critical to monitoring SARS-CoV-2 circulation and evolution, and mitigating its ongoing health and socioeconomic impacts.

Following the expiration of the last Global Strategic Preparedness and Response Plan (SPRP) from 2023-2025, WHO has published a high level strategic and operational plan for coronavirus disease threat management that sets out the global framework for supporting Member States in the sustained, integrated, evidence-based management of coronavirus disease threats, including COVID-19, MERS, and potential novel coronavirus diseases of public health importance. 

The plan builds on and supersedes previous WHO strategic preparedness and response plans for COVID-19. It emphasizes long-term, routine management of COVID-19 and other coronavirus diseases, embedded within national healthcare and health emergency systems and aligned with broader respiratory disease management strategies. An ‘At a glance’ document is available and provides a high-level overview of the plan in advance of a more detailed plan’s release.  

WHO released an updated package of policy briefs in December 2024 designed to help countries formulate evidence-based policies to manage SARS-CoV-2 transmission, particularly in high-risk and vulnerable populations, and to reduce morbidity, mortality and long-term sequelae from COVID-19. 

The briefs outline essential actions that national and sub-national policy-makers can implement to work towards comprehensive COVID-19 prevention and control. Member States should prioritize efforts to:

-- Maintain multi-source, multi-tiered collaborative surveillance systems for early detection, variant monitoring, and disease burden assessment, using both sentinel and wastewater surveillance, integrated into respiratory pathogen monitoring platforms.[7-8]

-- Ensure continued equitable access to and uptake of COVID-19 vaccines, particularly among high-risk groups, guided by national immunization strategies aligned with WHO SAGE recommendations.[9-10]

-- Strengthen healthcare delivery systems to ensure high-quality clinical management of COVID-19 and Post-COVID-19 Condition (PCC), embedded in scalable care models and featuring robust infection prevention and control standards.

-- Enhance risk communication and community engagement to empower individuals to make informed decisions, counter misinformation, and support community-led protection strategies.

-- Institutionalize national and subnational coordination mechanisms, including those developed during the acute phase of the pandemic, into long-term respiratory disease threat management systems, aligned with a One Health approach.

WHO further reminds Member States that the International Health Regulations (IHR) Standing Recommendations on COVID-19, issued by the Director-General following the expiration of the PHEIC in May 2023, remain valid through 30 April 2026. These recommendations provide ongoing guidance for sustained COVID-19 threat management, and WHO encourages countries to align their national policies with these recommendations to ensure continued vigilance and preparedness.

WHO recommends that countries remain vigilant, adapt to evolving epidemiological trends, and leverage COVID-19 management strategies to strengthen systems for all respiratory disease threats. Member States should continue offering COVID-19 vaccines in line with WHO recommendations.[11]

Based on the current risk assessment of this event, WHO advises against imposing travel or trade restrictions.

Further information

- WHO COVID-19 dashboard; https://data.who.int/dashboards/covid19/summary

- https://www.who.int/health-topics/coronavirus

- WHO Coronavirus disease (COVID-19) Fact sheet: https://www.who.int/news-room/fact-sheets/detail/coronavirus-disease-(covid-19)

- WHO Strategic and Operational Plan for Coronavirus Disease Management – At a glance: https://www.who.int/publications/m/item/strategic-and-operational-plan-for-coronavirus-disease-threat-management-at-a-glance

- WHO COVID-19 policy briefs: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/covid-19-policy-briefs

- Standing recommendations for COVID-19 issued by the Director-General of the World Health Organization in accordance with the International Health Regulations (2005) (IHR): https://www.who.int/publications/m/item/standing-recommendations-for-covid-19-issued-by-the-director-general-of-the-world-health-organization-(who)-in-accordance-with-the-international-health-regulations-(2005)-(ihr)

- Extension: https://apps.who.int/gb/ebwha/pdf_files/WHA78/A78_INF7-en.pdf   

- WHO Variant tracking with risk evaluation for circulating VOI and VUMs: https://www.who.int/activities/tracking-SARS-CoV-2-variants

- WHO SAGE Roadmap for prioritizing uses of COVID-19 vaccines: https://www.who.int/publications/i/item/WHO-2019-nCoV-Vaccines-SAGE-Prioritization-2023.1

- Statement on the antigen composition of COVID-19 vaccines: https://www.who.int/news/item/15-05-2025-statement-on-the-antigen-composition-of-covid-19-vaccines 

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[1] Director-General’s Standing Recommendations: https://apps.who.int/gb/ebwha/pdf_files/WHA78/A78_INF7-en.pdf  

[2] NB.1.8.1 initial risk evaluation: https://cdn.who.int/media/docs/default-source/documents/epp/tracking-sars-cov-2/23052025_nb.1.8.1_ire.pdf?sfvrsn=7b14df58_4

[3] Minimum age of ‘older adults’ is defined by Member States; often it is 50 or 60 years and older.

[4] India COVID-19 Statewise Status: https://covid19dashboard.mohfw.gov.in/

[5] Thailand: https://dvis3.ddc.moph.go.th/t/DDC_CENTER_DOE/views/_v2/sheet26?%3Aembed=y

[6] Updated working definitions and primary actions for SARS-CoV-2 variants: https://www.who.int/publications/m/item/updated-working-definitions-and-primary-actions-for--sars-cov-2-variants

[7] Surveillance for respiratory viruses of epidemic and pandemic potential: https://www.who.int/initiatives/mosaic-respiratory-surveillance-framework/

[8] Global Influenza Surveillance and Response System (GISRS): https://www.who.int/initiatives/global-influenza-surveillance-and-response-system

[9] Statement on the antigen composition of COVID-19 vaccines (15 May 2025): https://hq_who_departmentofcommunications.cmail20.com/t/d-e-shiliiy-ijjyjhwtr-g/

[10] WHO SAGE Roadmap for prioritizing uses of COVID-19 vaccines (10 November 2023): https://www.who.int/publications/i/item/WHO-2019-nCoV-Vaccines-SAGE-Prioritization-2023.1

[11]  WHO SAGE Roadmap for prioritizing uses of COVID-19 vaccines: https://www.who.int/publications/i/item/WHO-2019-nCoV-Vaccines-SAGE-Prioritization-2023.1

Citable reference: World Health Organization (28 May 2025). Disease Outbreak News; COVID-19 - Global situation. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON572

Source: World Health Organization, https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON572

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#Surveillance of avian #influenza through #bird #guano in remote regions of the global south to uncover transmission dynamics

Abstract

Avian influenza viruses (AIVs) pose a growing global health threat, particularly in low- and middle-income countries (LMICs), where limited surveillance capacity and under-resourced healthcare systems hinder timely detection and response. Migratory birds play a significant role in the transboundary spread of AIVs, yet data from key regions along migratory flyways remain sparse. To address these surveillance gaps, we conducted a study between December 2021 and February 2023 using fresh bird guano collected across 10 countries in the Global South. Here, we show that remote, uninhabited regions in previously unsampled areas harbor a high diversity of AIV strains, with H5N1 emerging as the most prevalent. Some of these H5N1 samples also carry mutations that may make them less responsive to the antiviral drug oseltamivir. Our findings documented the presence of AIVs in several underrepresented regions and highlighted critical transmission hotspots where viral evolution may be accelerating. These results underscore the urgent need for geographically targeted surveillance to detect emerging variants, inform public health interventions, and reduce the risk of zoonotic spillover.

Source: Nature Communications, https://www.nature.com/articles/s41467-025-59322-z

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#Cambodia's 4th #death of #H5N1 #birdflu recorded in 2025

PHNOM PENH, May 28 (Xinhua) -- An 11-year-old boy from western Cambodia's Kampong Speu province had died of H5N1 human avian influenza, becoming the fourth human death from the virus so far this year, the Ministry of Health said in a press statement released on Wednesday.

"A laboratory result from the Pasteur Institute of Cambodia showed on May 27, 2025, that the boy was positive for the H5N1 virus," the statement said.

The ill-fated boy lived in Samraong Tong district's Srey Sampoung village.

"According to queries, chickens and ducks near the patient's house had gotten sick and died subsequently a week before the boy fell ill," the statement said.

Health authorities are looking into the source of the infection and examining any suspected cases or people who have been in contact with the victim in order to prevent an outbreak in the community, it added.

The Southeast Asian country recorded a total of four human cases of H5N1 so far this year, with all deaths, and all patients reportedly had a history of recent exposure to sick or dead poultry prior to their illness.

H5N1 influenza is a flu that normally spreads between sick poultry, but can sometimes spread from poultry to humans. Its symptoms include fever, cough, runny nose, and severe respiratory illness.

The Ministry of Health called on people to be extra vigilant and not to eat ill or dead poultry, saying that bird flu still threatens people's health.

From 2003 to date, there were 76 cases of human infection with H5N1 influenza, including 47 deaths in the kingdom, according to the Ministry of Health

Source: Xinhua, https://english.news.cn/asiapacific/20250528/f6f6d89a657d4997a6df2f4b9ad12ba6/c.htmlhttps://english.news.cn/asiapacific/20250528/f6f6d89a657d4997a6df2f4b9ad12ba6/c.html

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Environmental #monitoring and spatiotemporal #trend #analysis of avian #influenza virus in #Xinjiang, 2021-2023

Abstract

Background

Avian influenza, a significant threat to public health, requires monitoring for the development of control strategies. This study aims to analyze the spatiotemporal distribution of avian influenza virus in the external environment of Xinjiang from 2021 to 2023, to enhance understanding of its transmission patterns and provide a scientific basis for public health response measures.

Methods

A total of 3913 avian-related environmental samples were collected from nine monitoring areas in Xinjiang. Sample types included poultry drinking water, meat cutting boards, cage surfaces, feces, and wastewater. Real-time RT-PCR was used to detect nucleic acid for H5, H7, and H9 subtypes. Data were statistically analyzed using Excel and SPSS, and spatial distribution was visualized through Kriging interpolation using ArcGIS.

Results

Among the collected samples, 810 tested positive, with an overall positivity rate of 20.70%. The H9 subtype was predominant, accounting for 85.43% of positive samples. Significant differences in detection rates were observed across different years, regions, sample types, and monitoring sites. Temporally, the positive rate showed an upward trend from 2021 to 2023, with higher positive rates in January and July. Geographically, Aksu, Turpan, and Ili were identified as high-risk areas. Urban and rural live poultry markets had the highest positivity rate (24.31%), and poultry drinking water, cage surfaces, and cleaning wastewater samples showed relatively high detection rates. Kriging analysis revealed several high-risk zones for virus presence.

Conclusion

This study provides crucial information for understanding the epidemiological characteristics of avian influenza virus in the external environment of Xinjiang. The H9 subtype was found to be predominant, with notable seasonal and regional variations. Live poultry markets were identified as key risk sites. These findings underscore the need for continuous surveillance and offer theoretical support for developing targeted prevention and control strategies. However, the limited scope of monitoring suggests that broader and longer-term studies are needed to better understand subtype interactions and epidemic risks.

Source: BMC Infectious Diseases, https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-025-11155-3

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Novel Highly Pathogenic Avian #Influenza A #H5N1 Triple #Reassortant in #Argentina, 2025

Abstract

Genomic sequencing of re-emerging highly pathogenic avian influenza A(H5N1) virus detected in Argentina in February 2025 revealed novel triple-reassortant viruses containing gene segments from Eurasian H5N1 and low pathogenic viruses from South and North American lineages. These findings underscore continued evolution and diversification of clade 2.3.4.4b H5N1 in the Americas.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.05.23.655175v1

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Characteristics of the first confirmed case of #human #infection with #mpox virus clade Ib in #China

Abstract

Mpox clade Ib is significant as it is associated with human cases and plays a key role in understanding the transmission and public health implications of mpox outbreaks. Here we present a case report of the first confirmed human infection of clade Ib in China, which occurred in December 2025 in Zhejiang Province. The case was a 28-year-old woman from South Africa who had sexual contact with an asymptomatic man from the Democratic Republic of the Congo. She presented with disseminated vesicular lesions on the extremities, face, buttocks, trunk, palms, and dorsum of the hands, but lesions were absent from the oral cavity, perineum, and anus. By the 18th day post-onset (DPO), only vesicles remained on the dorsum of the right foot and in the finger web spaces, with complete resolution by the 24th DPO. Among 59 consecutive samples collected, 55 tested positive for mpox virus. Oropharyngeal swabs turned negative by the 16th DPO, while skin lesion samples, urine samples, and scab specimens remained positive through the 20th DPO. Consecutive scab samples consistently exhibited high viral loads. In total, 211 contacts of the symptomatic patient were identified, and no secondary cases occurred. This study underscores the importance of multisite sampling for diagnostic sensitivity, highlights the transmission risk associated with asymptomatic sexual contact, and emphasizes the need for refined contact definitions and management strategies. Further research is needed to explore infection risks across different types of exposure.

Source: Nature Communications, https://www.nature.com/articles/s41467-025-60217-2

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Avian #Influenza in #Ireland: A Spatiotemporal, Subtype, and Host-Based Analysis (1983-2024)

Abstract

Avian influenza virus (AIV) is a significant global concern, causing widespread mortality in wild birds, domestic poultry and most recently wild and domestic mammals. This study presents a retrospective analysis of AIV detections in the Republic of Ireland. Data was sourced from official surveillance databases, peer-reviewed literature and grey literature sources. Spatio-temporal, host-specific and subtype patterns were assessed using descriptive statistics, chi-square tests, linear regression and kernel density estimations. A total of 2,888 confirmed AIV detections were recorded from 25 of Ireland's 26 counties. Wild birds accounted for 98.7% of detections, with domestic birds comprising 1.3% and two detections in foxes. H5N1 was the most prevalent subtype (96.7%) followed by H5N8 and H6N1. Spatial clustering was observed in urban areas, particularly Dublin. The highest seasonal peak occurred during summer, contrasting with traditional winter-associated patterns. Several detections occurred in migratory species outside of typical residency periods, suggesting potential climate-related shifts in migration behaviour. This study represents the first review of AIV surveillance data in Ireland to date. The findings highlight evolving patterns in virus distribution, seasonality and host dynamics, with implications for national surveillance strategies. Continued cross-species monitoring and integration of ecological data are essential to inform effective management strategies.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.05.26.656175v1

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Comparative #risk #assessment of spread of highly pathogenic avian #influenza #H5 viruses in French #broiler and layer sectors.

Abstract

Since 2015, French poultry production is threatened almost every year by a reintroduction of highly pathogenic avian influenza H5 viruses. The duck sector was the most concerned by this crisis but other sectors such as broiler, layer and turkey were also affected by outbreaks. The objective of this work was to assess the risk of highly pathogenic avian influenza H5 virus transmission from one farm to another within the French broiler and layer production network. This study used the WOAH risk assessment framework. After drawing up a scenario tree of virus transmission from one farm to another, data were collected through a literature review or through experts' elicitation. Three questionnaires were developed according to the experts' field of expertise: avian influenza, broiler and layer sectors. The experts' estimates were combined using a beta distribution weighted by their confidence level. A Monte Carlo iteration process was used to combine the different probabilities of the scenario tree and to assess the transmission risk. In the broiler sector, the highest transmission probabilities were observed if the exposed farm was an indoor broiler farm and the source a broiler farm (indoor or free-range). The high transmission probability between broiler farm integrated within the same company highlighted the role of integration in this probability. The pathways which generated the highest transmission probabilities between two integrated indoor broiler farms with a good biosecurity level are person movement, transport of feed and manure management. In the layer sector, the highest transmission probabilities were observed if the source farm was a free-range farm and the exposed farm a production farm (indoor or free-range). The pathways with the highest transmission probabilities were egg transport and person movement. The sensitivity analysis showed that the exposed farm's biosecurity had a significant impact on the transmission probability. Our results provide an insight on the role of each type of farms in the virus spread within the French broiler and layer production sectors and will be useful for the implementation of control measures such as movement restriction or vaccination.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.09.11.612235v3

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#HK PRC SAR, Avian #Influenza #Report - Week 21 '25 (excerpts): One New #Human #H5N1 Case in #China

{Excerpts}

Influenza A H5N1 Virus

-- Date: 23/05/2025, 

-- Location: China*, Guangxi Zhuang Autonomous Region, 

-- Sex: Female, 

-- Age: 53,  

-- Clinical Status: Recovered, 

-- Virus Subtype: H5N1.

(...)

Source: Centre for Health Protection, Hong Kong PRC SAR, https://www.chp.gov.hk/files/pdf/2025_avian_influenza_report_vol21_wk21.pdf

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Global #risk #mapping of highly pathogenic avian #influenza #H5N1 and H5Nx in the light of epidemic episodes occurring from 2020 onward

Abstract

Avian influenza (AI) is a highly contagious viral disease affecting poultry and wild water birds, posing significant global challenges due to its high mortality rates and economic impacts. Highly pathogenic avian influenza (HPAI) outbreaks, particularly those caused by H5N1 and its variants, have surged since their first occurrence in 1959. The HPAI H5N1 clade 2.3.4.4b viruses have notably expanded its geographical reach, affecting numerous countries, diverse avian species, and now wild and domestic mammals. Using an ecological niche modelling approach, this study aims to elucidate the environmental factors associated with the increased HPAI H5 cases since 2020, investigate potential shifts in ecological niches, and predict new areas suitable for local viral circulation. Focusing on H5N1 and H5Nx strains, we have developed ecological niche models for HPAI case in both wild and domestic birds while considering two distinct periods: 2015-2020 and 2020-2022. Key environmental predictors include chicken and duck population density, human density, distance to water bodies, and several land cover variables. Post-2020, we observe a notable increase in the relative importance of some of these predictors, such as intensive chicken population density and cultivated vegetation. The resulting risk maps reveal notable ecological suitability for local HPAI H5 circulation in Europe, Asia, as well as North and South America, with notable expansions of the areas at risk post-2020. The spatial distribution of HPAI H5 occurrences in wild birds appears to be primarily influenced by urban areas and open water regions. Overall, global risk maps derived from our models identify regions at risk where surveillance and control measures should be prioritised. Finally, our analyses also highlight a shift in the diversity of species affected by HPAI outbreaks, with a higher variety of avian species, particularly sea birds, being impacted post-2020. This increased diversity suggests that ecological shifts in HPAI H5 circulation may be accompanied by a broader range of susceptible species. Overall, these results further contribute to the understanding of HPAI epidemiology.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.11.15.623755v2

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Home Again, Frederick McCubbin (1884)

 

Public Domain.

Source: WikiArt, https://www.wikiart.org/en/frederick-mccubbin/home-again-1884

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