#Livestock production intensity and mucosal #IgA and #IgG responses to #H5N1 highly pathogenic avian #influenza A virus, North Carolina, 2021-2022

 

Abstract

Background. 

Direct livestock exposure is a risk factor for zoonotic influenza, including H5N1 highly pathogenic avian influenza (HPAI) A virus. But whether living in regions of high poultry and swine production intensity (PPI, SPI) increases risk of exposure to zoonotic influenza viruses independent of occupational livestock contact remains unclear. 

Objectives. 

To determine whether livestock workers and community members with no occupational livestock exposure in North Carolina, where poultry and swine production are increasingly co-located, are at higher risk of exposure to zoonotic influenza. 

Methods. 

Saliva samples from industrial livestock operation worker (ILO-W), ILO neighbor (ILO-N) and metropolitan area (Metro) households were analyzed for mucosal influenza A (H5N1, H1N1, and H3N2) hemagglutinin (HA) IgA and IgG antibodies to determine associations of PPI, SPI, exposure group, and detection of a swine-specific fecal contamination marker (Pig-2-Bac DNA) with influenza A antibody levels. 

Results. 

Residing in the highest PPI and SPI tertile was associated with significantly higher mucosal H5 and H1 HA IgA levels, including among residents without occupational livestock exposure. Households with occupational poultry or swine contact had significantly higher H5 IgA and IgG and H1 IgA levels compared to Metro households. In regression models accounting for clustering at the participant level, log10 anti-H5 HA mucosal IgA increased 0.16 (95% CI: 0.06, 0.27, p<0.005) and 0.10 (95% CI: 0.03, 0.17, p<0.005), per log10 increase in PPI and SPI, respectively, and 0.16 (95% CI: 0.03, 0.19, p<0.02) when Pig-2-Bac DNA was detected on household surfaces. 

Conclusions. 

Mucosal H5 HA IgA and IgG and H1 HA IgA were consistently elevated across different metrics of livestock exposure intensity, including residential exposure, occupational contact within a household, and a molecular marker of household swine fecal contamination in a state with intensive poultry and swine production.

Competing Interest Statement

The authors have declared no competing interest.

Source: 

Link: https://www.medrxiv.org/content/10.64898/2026.08.06.26359901v1

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#SARS-CoV-2 #Surveillance in Free-Ranging #Wildlife in New England and #Virginia, #USA, 2022–2025

 

Abstract

Since its emergence in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected a wide range of animal species, including wildlife. Although SARS-CoV-2 infection has been widely reported in wildlife, particularly in white-tailed deer (WTD; Odocoileus virginianus) across the United States, data on viral circulation in New England wildlife remain limited. Here, we investigated active SARS-CoV-2 infection and serological evidence of previous exposure in free-ranging wildlife from New England and Virginia. We examined samples from 1646 animals representing 29 wildlife species, collected through wildlife rehabilitation centers, clinics, and hunter harvests in New England and Virginia between 2022 and 2025. SARS-CoV-2 RNA was detected in three WTD from Massachusetts and Vermont. Phylogeographic analysis showed that the Vermont WTD SARS-CoV-2 sequences were closely related to contemporaneous human SARS-CoV-2 sequences from the same region, consistent with a possible human-to-deer spillover event. Serological screening by ELISA detected SARS-CoV-2 reactive samples in nine individuals from three species, including Eastern cottontail (Sylvilagus floridanus), Eastern coyote (Canis latrans), and raccoon (Procyon lotor), providing putative evidence of prior SARS-CoV-2 exposure. However, neutralizing antibodies against the SARS-CoV-2 Omicron variant were detected in only a single Eastern cottontail. Overall, these findings indicate sporadic SARS-CoV-2 detection and limited serological evidence of prior exposure among wildlife sampled in New England and Virginia, and highlight the importance of continued surveillance to detect spillover events, monitor viral evolution, and assess the potential risks associated with wildlife reservoirs.

Source: 

Link: https://www.mdpi.com/1999-4915/18/8/832

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#Seroprevalence of #Influenza #H5N1 Virus in Domestic #Cats at Epicenter of Dairy #Cattle #Outbreaks, #California, #USA, 2024–2026

 

Abstract

We conducted a serologic study of domestic cats near the epicenter of the dairy cattle outbreaks of influenza A(H5N1) in California, USA. Three of the 12 cats sampled within 2 km of farms had neutralizing antibodies against H5N1 virus. Proximity to dairy farms was a statistically significant risk factor for seropositivity.

Source: 

Link: https://wwwnc.cdc.gov/eid/article/32/9/26-0785_article

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Clade 2.3.4.4b #H5N1 #influenza virus and #SARS-CoV-2 #seroprevalence among owned and feral #cats in #Philadelphia and surrounding communities

 

Abstract

Clade 2.3.4.4b H5NX influenza viruses have spread widely in birds since 2020. In addition to causing disease in birds, these viruses have infected a variety of mammals, including humans. Clade 2.3.4.4b H5N1 viruses are currently causing an outbreak among dairy cattle in the United States, and it is important to determine if other mammals have been exposed to H5NX viruses. Cats, specifically outdoor and feral cats, frequently predate wild birds. Recent studies have shown that cats living on dairy cattle farms can be infected with H5N1. Here, we completed serological studies to determine if owned and feral cats living in an urban environment in the United States have evidence of past H5N1 exposures. We used multianalyte bead-based assays to measure clade 2.3.4.4b hemagglutinin (HA) antibody levels in serum samples collected in July 2023 to June 2025 from 417 feral and 228 owned cats from the greater Philadelphia area. We also measured antibody levels against a panel of HAs from other human and non-human influenza viruses, and the receptor binding domain (RBD) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We completed additional H5N1 and SARS-CoV-2 neutralization assays using samples that had detectable antibodies in the multianalyte bead-based assays. One cat (0.16%) was positive for H5 antibodies and twenty cats (3.1%) were positive for SARS-CoV-2 antibodies in both binding and neutralization assays. These data suggest that cats in the Philadelphia area have not been routinely exposed to clade 2.3.4.4b H5N1 viruses but have been more commonly exposed to SARS-CoV-2.

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.07.03.736283v1

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Detection of #antibodies against avian #influenza in #European dairy #cattle, the #Netherlands, January 2026

 

Abstract

In December 2025, highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b genotype DI.2.1 virus was detected in a cat living on a dairy cattle farm. Milk and serum samples from the dairy cattle were tested for avian influenza virus. No viral RNA was detected; however, H5N1-specific antibodies were identified in serum samples from 34 (47.2%) of 72 lactating dairy cows and 24 (63.2%) of 38 youngstock. These demonstrate expansion of the mammalian host range of HPAI H5N1 in Europe.

Source: 

Link: https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2026.31.25.2600464#abstract_content

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Epidemiological and Virological Characteristics of #H9N2 Avian #Influenza Virus in #Jiangsu Province, #China, 2024

 

Abstract

H9N2 avian influenza viruses inherently carry cross-species transmission potential, making continuous surveillance critical for pandemic prevention. This study focused on monitoring the 2024 H9N2 epidemic in Jiangsu Province’s external environment, analyzing its molecular evolution and receptor binding properties, assessing cross-species transmission and pandemic risks, and investigating serological antibody levels across different human populations. Environmental samples were collected from live poultry markets, farms, slaughterhouses, and bird habitats across Jiangsu, screened via quantitative PCR (qPCR), with positive samples used for virus isolation and whole-genome sequencing. Receptor binding properties were tested by hemagglutination assay, and H9N2 antibody levels were measured in 370 occupationally exposed individuals and 240 non-exposed individuals using hemagglutination inhibition (HI) assays. Among the 5779 collected samples, 6.89% tested H9N2-positive, and 12 strains belonging to the Eurasian lineage Y280-like clade G57 genotype were successfully isolated. All strains carried the HA-Q226L mutation, with 11 showing preferential binding to human α-2,6 receptors and one strain possessing dual receptor binding capability. Internal genes harbored mammalian adaptation mutations, and M2 proteins contained mutations conferring complete resistance to amantadine-class antiviral drugs. Serological tests revealed antibody positive rates of 4.05% in exposed populations and 2.5% in non-exposed populations, with no statistically significant difference between groups. These findings confirm that Jiangsu’s circulating H9N2 viruses have acquired human receptor preference and mammalian adaptation, posing silent infection and pandemic risks. Enhanced surveillance and the development of candidate vaccine stockpiles are strongly recommended.

Source: 

Link: https://www.mdpi.com/1999-4915/18/6/687

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Detection of Anti- #H5 #Antibodies in People with Exposure to Wild #Birds in Northern #Canada

 

Abstract

Using a commercially available H5 serology assay, we identified a 7.4% (n=5/68) anti-H5 seroreactivity rate among hunters in Northern Canada. All participants reported close contact with wild birds.

Competing Interest Statement

This study was performed outside of JK's duties and responsibilities with the Public Health Agency of Canada.

Source: 

Link: https://www.medrxiv.org/content/10.64898/2026.05.24.26353994v1

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#Hantavirus #seroprevalence and associated factors for exposure in south-central #Uganda

 

ABSTRACT

Orthohantaviruses are largely rodent-borne pathogens that can cause haemorrhagic fever with renal syndrome and hantavirus cardiopulmonary syndrome. In Uganda, the risk of human exposure is heightened by known rodent hosts, close human-rodent interaction in rural areas, and poor housing conditions. Despite this risk, data on human exposure remain scarce. This study sought to ascertain the seroprevalence of orthohantavirus exposure and identify associated factors with exposure among residents of the greater Masaka-Rakai region in Uganda. Seropositivity was assessed for orthohantavirus-specific IgG antibodies using commercial enzyme-linked immunosorbent assays. Logistic regression models were used to identify factors associated with seropositivity. Among 1,199 sera samples, orthohantavirus population-weighted seroprevalence was 7.4% (95% CI: 3.91–10.80). Males had a higher seroprevalence, while higher socioeconomic status was associated with a reduced burden of exposure to orthohantavirus. This study reports evidence of orthohantavirus exposure in Uganda, highlighting a previously underrecognized zoonotic risk in the region likely driven by close contact with rodent reservoirs and poor living conditions. The higher burden among males and lower-burden association with higher socioeconomic status, highlights the need for improved housing, rodent control, and integration of orthohantavirus surveillance into national public health programmes.

Source: 

Link: https://www.tandfonline.com/doi/full/10.1080/22221751.2026.2665002

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#Genetic and #biological characterization of #H9N2 avian #influenza viruses isolated from #swine in #China

 

Abstract

Background

H9N2 avian influenza virus (AIV) has been circulating in poultry in China for decades and are undergoing adaptation to mammals, posing potential pandemic risks. To investigate the prevalence of H9N2 AIVs in swine, we conducted surveillance in Shandong Province from 2021 to 2023.

Results

Two H9N2 influenza virus strains, A/swine/Shandong/417/2021(Sw/SD/417/21) and A/swine/Shandong/662/2022 (Sw/SD/662/22), were successfully isolated from swine and genetically characterized. Phylogenetic analyses showed that both isolates were reassortants containing gene segments from multiple H9N2 AIV lineages and closely related to currently circulating H9N2 AIV. Key molecular marker analysis revealed that both isolates carried mammalian-adaptive residues in the HA receptor-binding sites (183 N, 190 V, 226 L), a novel HA cleavage site variant (PSKSSRGL), PB2 mutations (A588V, E627V), and the M2 S31N substitution, suggesting potential adaptation to mammalian hosts and resistance to adamantane antivirals. Mice infection experiments demonstrated efficient viral replication in the respiratory tract, particularly in the lungs, but only mild histopathological changes were observed, with no significant weight loss or mortality, indicating low pathogenicity in mice. Serological surveillance of 3,172 swine serum samples showed a low prevalence of H9N2 influenza virus infection (0.44%), with positive samples sporadically distributed across regions and years.

Conclusion

In summary, although H9N2 AIV infection in swine is rare and generally mild, the presence of mammalian-adaptive markers and reassortant genomes highlights the potential risk of cross-species transmission and subclinical adaptation. Continuous avian–swine–human influenza surveillance is therefore essential to mitigate the potential threat posed by H9N2 AIV.

Source: 

Link: https://link.springer.com/article/10.1186/s12917-026-05501-z

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#Surveillance on #California dairy #farms reveals multiple possible sources of #H5N1 #influenza virus #transmission

 

Abstract

Transmission routes of highly pathogenic H5N1 between cows or to humans remain unclear due to limited data from affected dairy farms. We performed air, farm wastewater, and milk sampling on 14 H5N1-positive dairy farms across two different California regions. Infectious virus was detected in the air in milking parlors and in wastewater streams, while viral RNA was found in exhaled breath of cows. Sequence analysis of infectious H5N1 virus from air and wastewater samples on one farm revealed viral variants relevant for potential human susceptibility. Longitudinal analysis of milk from the individual quarters of cows revealed a high prevalence of subclinical H5N1-positive cows. Additionally, a heterogeneous distribution of infected quarters that maintained a consistent pattern over time was observed, inconsistent with shared milking equipment serving as the sole transmission mode. The presence of subclinically infected cows was further supported by detection of antibodies in the milk of animals that exhibited no clinical signs during the H5N1 outbreak on one farm. Our data highlight additional sources and potential modes of H5N1 transmission on dairy farms.

Source: 

Link: https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3003761

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#Orthopoxvirus #Antibodies in Feral #Mammals in #Mpox #Outbreak Areas, #Nigeria, 2021–2022

 

Abstract

We analyzed tissue and serum samples from 124 wild animals from communities with confirmed mpox cases in Nigeria. Tissue samples were PCR-negative, but serum samples from 8 animals (6.45%)—3 feral cats, 4 giant pouched rats, and 1 shrew—revealed Orthopoxvirus antibodies, suggesting these species as probable reservoirs.

Source: 

Link: https://wwwnc.cdc.gov/eid/article/32/5/25-1565_article

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Serologic #Surveillance of Highly Pathogenic Avian #Influenza Virus Subtype #H5 in #Wildlife, Northeast #Germany, 2023–2025

 

Abstract

We tested wild ruminants, boar, and carnivores in northeast Germany for highly pathogenic avian influenza subtype H5 antibodies. Wild ruminants were seronegative, but 3.5% of boar and 12.5%–21.9% of carnivores were seropositive, indicating frequent spillover. Because such events might accelerate mammalian (and ultimately human) adaptation, sustained monitoring remains essential.

Source: 

Link: https://wwwnc.cdc.gov/eid/article/32/5/25-1555_article

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#Evidence of #SARS-CoV-2 #Exposure in #Rodents from Rural Localities in the #Yucatan Peninsula, #Mexico

 

Abstract

Zoonotic diseases involve pathogen transmission between humans and animals, with most research focused on animal-to-human spillover. However, reverse zoonosis—the transmission of pathogens from humans to animals—remains understudied despite its potential ecological and epidemiological consequences. The SARS-CoV-2 pandemic highlights this risk, as human-associated viruses may sporadically infect wildlife species and generate novel exposure pathways. To assess evidence of SARS-CoV-2 exposure in wildlife, we analyzed serum and rectal swab samples from rodents collected in rural localities of the Yucatan Peninsula, Mexico, between 2021 and 2022. An indirect ELISA detected antibodies against SARS-CoV-2 in 23.1% of sampled rodents. Molecular analysis detected one positive sample with a pan-coronavirus RT-PCR, though all were negative for SARS-CoV-2–specific assays. This study provides serological evidence of SARS-CoV-2 exposure in rodent communities from rural areas of Mexico and is consistent with sporadic wildlife spillback events rather than sustained transmission. The observed exposure patterns may be influenced by human activities and frequent human–wildlife interactions in heterogeneous rural landscapes. Our results underscore the need for integrated serological and genomic surveillance to better understand the ecological context of reverse zoonosis and its implications for public health.

Source: 

Link: https://www.mdpi.com/1999-4915/18/4/435

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#Serological #Surveillance of Avian #Influenza Virus #H9N2 Subtype in #Occupational Populations Exposed to #Poultry Environment in #China During 2018–2023

 

Abstract

Background

Avian influenza virus (AIV) H9N2 has a major role in the emergence of influenza pandemic. We assessed the risk of AIV H9N2 to the human population and public health.

Method

The hemagglutination inhibition method was used to screen for hemagglutinin antibodies. Microneutralization tests were performed to confirm neutralizing antibodies against the AIV H9N2 subtype. Real-time polymerase chain reaction was conducted to detect the H9 subtype in environmental samples. GraphPad Prism software was used for mapping, and STATA software was used for statistical analysis.

Results

The nationwide seroprevalence among these populations was 0.76%. Seroprevalence was compared across regions, genders, and occupational exposure sites. The seroprevalence rates for males and females showed no significant difference. Significant differences were found across regions and occupational exposure environments (P < .05). The south and southwest regions had the highest seroprevalence rates at 1.58% and 1.38%, respectively. The highest seroprevalence was observed in individuals exposed to live poultry market (1.51%). Significant regional differences in H9 nucleic acid positive rates (NAPRs) were found (P < .05), with the southwest and central regions showing the highest rates at 25.99% and 24.35%, respectively. H9 NAPR in live poultry markets (LPMs), farms, and slaughterhouses varied significantly by region (P < .05).

Conclusions

Poultry-related environments have become a key factor in AIV H9N2 infection among occupational populations. Exposure to LPM showed the highest seroprevalence among occupational groups. The distribution characteristics of H9N2 across different poultry environments increased the risk of infection in occupationally exposed populations.

Source: 

Link: https://academic.oup.com/ofid/article/13/4/ofag144/8537381

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#MERS #Coronavirus–Specific T-Cell Responses in Dromedary #Camel #Abattoir #Workers in #Nigeria Suggests Frequent Zoonotic #Spillover

 

Abstract

Middle East respiratory syndrome coronavirus (MERS-CoV) is assessed to have high pandemic risk, and dromedary camels are the source of zoonotic spillover. More than 75% of MERS-CoV–infected dromedary camels are found in Africa, but no zoonotic disease has been reported from Africa where there is little awareness of MERS-CoV as a potential cause of respiratory disease. Antibody responses are a poor indicator of mild infection. We found that 47 of 60 (78%) dromedary camel abattoir workers in Kano, Nigeria, had MERS-CoV–specific T-cell responses while none of 18 controls did, suggesting that zoonotic infection is common in camel-exposed individuals in Africa.

Source: 

Link: https://academic.oup.com/jid/advance-article-abstract/doi/10.1093/infdis/jiag095/8504072?redirectedFrom=fulltext

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Serological and viral #prevalence of #Oropouche virus (OROV): A systematic review and meta-analysis from 2000–24 including #human, #animal, and #vector #surveillance studies

 

Abstract

Background

Oropouche virus (OROV) is an emerging arbovirus primarily transmitted by biting midges and is increasingly recognized as a public health threat in Central and South America. With over 11,000 confirmed cases reported in 2024, a ten-fold increase from the previous year, its transmission dynamics and true burden remain poorly understood due to diagnostic challenges and fragmented surveillance systems.

Objective

This systematic review and meta-analysis (SRMA) synthesizes OROV prevalence data in humans and summarizes the available data for vectors and animal hosts sampled between 2000 and 2024 to provide updated estimates and identify key surveillance gaps.

Methods

We systematically searched Web of Science, PubMed, Embase, Medline, and LILACS for OROV seroprevalence and viral prevalence studies in human, insect, and animal populations, published up to September 12, 2024. The review protocol was registered with PROSPERO (CRD42024551000). Studies were extracted in duplicate, and data were meta-analyzed using generalized linear mixed-effects models. Risk of bias was appraised using a modified Joanna Briggs Institute checklist.

Results

We included 71 articles reporting serological or viral prevalence of OROV across nine countries. Between 2000–2024, pooled human seroprevalence among individuals with febrile illness or suspected of Oropouche infection was 12.6% [95% CI 5.3-26.9%] across four South American countries and seroprevalence of 1.1% [95% CI 0.5-2.3%] was observed in asymptomatic groups. Viral prevalence among individuals with febrile illness or suspected of Oropouche infection was 1.5% [0.8-3.0%] across seven South American countries and Haiti. Most studies used convenience sampling and RT-PCR or hemagglutination assays. In vector populations, positive OROV prevalence in Aedes aegypti and Culex quinquefasciatus was reported in two of 18 sources, while 10.0% and 7.5% animal host prevalence was reported in dogs and cattle, respectively. We found high risk of bias in 11.3% of studies in our critical appraisal, with most animal, human, and vector studies falling in the moderate risk of bias range.

Conclusions

Despite rising numbers of OROV reported cases, prevalence estimates remain limited by sparse surveillance and variable methodology. This review highlights the urgent need for standardized serological assays, community-based studies, and expanded surveillance in animal and vector reservoirs. A One Health approach is essential to monitor OROV transmission and inform regional preparedness efforts.

Source: 

Link: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0013340

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#Serological evidence of concurrent #Lassa virus and #SARS-CoV-2 #exposure in #Ghana- a cross-sectional study

 

Abstract

Background

The COVID-19 pandemic has exposed vulnerabilities in infectious disease surveillance, especially in West Africa where endemic viruses including Lassa fever persist. The overlapping clinical symptoms of these two infections create diagnostic challenges and the possibility of undetected co-infections.

Methods

A retrospective cross-sectional study was conducted using archived serum samples from a nationwide SARS-CoV-2 seroprevalence survey in Ghana. 434 samples across six regions were tested for SARS-CoV-2 total antibodies (IgG/IgM) using the WANTAI ELISA kit and Lassa virus IgG using ReLASV Pan-Lassa-NP-IgG ELISA.

Results

SARS-CoV-2 antibody prevalence was 64.29% (n = 279) and Lassa virus IgG prevalence was 20.28% (n = 88). Of the cohort of subjects who were seropositive for SARS-CoV-2, 20.79% were also seropositive for LASV IgG. Multivariate analysis revealed household size as a strong risk factor of dual exposure. Individuals from medium-sized households (4–6 persons) (aOR = 8.78, 95% CI: 1.18–65.56, p = 0.034) and large households (≥ 7 persons) (aOR = 12.90, 95% CI: 1.99–83.40, p = 0.007) had significantly increased odds of dual seropositivity compared to small households. Regional variations were observed, with Greater Accra showing significantly lower odds of dual seropositivity (aOR = 0.13, 95% CI: 0.03–0.51, p = 0.004) compared to Ashanti Region.

Conclusion

This study provides serological evidence of SARS-CoV-2 and Lassa virus concurrent exposure in Ghana during the COVID-19 pandemic. This finding suggests large household size as a key driver of dual viral exposure and calls for integrated surveillance systems and targeted interventions in large household settings to reduce concurrent transmission of viruses with pandemic potential.

Source: 

Link: https://link.springer.com/article/10.1186/s12879-025-12385-1

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Local and introduced #lineages drive #MERS-CoV #recombination in Egyptian #camels

 

ABSTRACT

Dromedary camels are the primary reservoir for Middle East respiratory syndrome coronavirus (MERS-CoV), a zoonotic coronavirus responsible for sporadic human infections. While clade B predominates in the Arabian Peninsula and is frequently linked to zoonotic outbreaks and household secondary transmission, clade C circulates primarily in African camels, with limited evidence of human infections. The extent of MERS-CoV transmission, genetic diversity, and cross-species potential in North Africa remains poorly characterized. Here, we investigate MERS-CoV incidence, seroprevalence, and genomic recombination in dromedary camels and sympatric livestock across slaughterhouses and farms in Egypt. MERS-CoV was detected in 12% of camels sampled at slaughterhouses, with no evidence of infection in cattle, buffalo, sheep, or goats. Seroprevalence was higher in slaughtered camels (79%) than camels on farms (12%). Phylogenetic analyses of MERS-CoV genomes obtained from dromedary camels revealed an introduction of clade B into Egypt, originating from the Arabian Peninsula. Furthermore, we identified recombination events between clades B and C, in addition to events within each clade. This included at least one clade C virus that acquired multiple genomic regions from the newly introduced clade B viruses. These findings suggest that newly introduced MERS-CoV strains can recombine with locally circulating viruses, generating novel variants with potential zoonotic implications and challenging assumptions of limited cross-regional exchange. Enhanced surveillance, targeted control measures, and a One Health approach are crucial to mitigating MERS-CoV transmission and the emergence of recombinant strains.

IMPORTANCE

This study highlights the importance of monitoring Middle East respiratory syndrome coronavirus (MERS-CoV) in dromedary camels, which are the main animal source of this virus that can occasionally infect humans. While most human cases have been linked to strains in the Arabian Peninsula, this research focused on Egypt, where the virus is less understood. Among surveyed dromedary camels and associated livestock, a significant number of camels at slaughterhouses were infected, and many had antibodies showing past exposure. Importantly, we discovered that a strain common in the Arabian Peninsula had recently entered Egypt and mixed genetically with local strains. This mixing, or recombination, can lead to new virus versions that may pose new risks to humans. The findings challenge the belief that MERS-CoV strains in different regions do not interact and highlight the need for stronger monitoring and prevention strategies. A One Health approach, linking animal, human, and environmental health, is key to managing future risks.

Source: 

Link: https://journals.asm.org/doi/full/10.1128/jvi.00641-25?af=R

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The #epidemiology of #chikungunya virus in #Brazil and the potential #impact of #vaccines: a mathematical modelling study

 

Summary

Background

The first chikungunya virus (CHIKV) vaccine is now licensed in Brazil, the country that reports the most cases of CHIKV globally; however, the optimal use of the vaccine remains unclear owing to a poor understanding of CHIKV epidemiology and population immunity. We aimed to combine the distribution of cases and deaths reported since 2014 with seroprevalence studies to inform mathematical models that estimate the underlying rates of infection by state and year, and the underlying patterns of disease and death by age and sex.

Methods

We quantified the annual CHIKV infection and disease burden between 2014 and 2024 in each of the 27 federative units of Brazil using a mathematical model in a Bayesian framework that integrated serological surveys (n=12) and confirmed CHIKV disease cases (n=488 234) and CHIKV deaths (n=1719) reported between January, 2014, and September, 2024. Using this base, we estimated the potential impact of a vaccine over the period 2025–29 had the population been vaccinated before the 2025 season, evaluating different roll-out strategies.

Findings

We found that 18·3% (95% credible interval 16·5–20·3) of the Brazilian population has been infected since 2014, with the highest risk concentrated in the northeast and southeast. Overall, 1·13% (1·07–1·19) of infections were detected by surveillance systems, with an increasing probability of symptoms with age and greater risk of symptoms in females. Vaccinating 40% of the population older than 12 years (73 million doses), and assuming a vaccine efficacy of 70% against infection and 95% against disease, would avert up to 1·6 million (0·5–3) cases and 198 (61–359) deaths over the next 5 years.

Interpretation

Despite widespread circulation, most of Brazil remains susceptible to infection. CHIKV vaccination has the potential to substantially reduce disease burden.

Funding

CEPI.

Source: 

Link: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(25)00605-X/fulltext?rss=yes

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Serological #Evidence of Exposure to Eurasian-Lineage HPAI #H5N1 Clade 2.3.4.4b in Wild #Mammals in #Ohio, #USA, 2024–2025

 

Abstract

The Goose/Guandong lineage of highly pathogenic avian influenza virus [A/Goose/Guangdong/1/1996(H5N1)] is the progenitor of the currently circulating Eurasian-lineage highly pathogenic avian influenza H5N1 clade 2.3.4.4b and has been the most consequential highly pathogenic avian influenza lineage globally. Despite increased reports of infections, the extent of exposure and role of wild mammals in the ecology and transmission dynamics of the virus remains poorly understood. We surveyed wild mammals in Ohio, United States to investigate the potential spillover of highly pathogenic H5N1 avian influenza clade 2.3.4.4b. While no active infections—defined as positive results indicative of viral replication and potential propagation—were detected by swab-based molecular tests, serological assays revealed antibodies against multiple avian influenza virus antigens in raccoons and opossums. Specifically, antibodies to avian influenza virus nucleoprotein were detected in 54.9% (n = 61) of samples using enzyme-linked immunosorbent assay; antibodies to Eurasian-lineage highly pathogenic avian influenza H5 clade 2.3.4.4b and North American low pathogenic avian influenza H5 were detected in 43.2% (n = 48) and 22.5% (n = 25) of samples, respectively, using virus neutralization assays; and antibodies to avian influenza virus neuraminidase were detected in 44.1% (n = 49) of samples using enzyme-linked lectin assay. All seropositive animals were sampled at Ohio marshes with previously confirmed highly pathogenic avian influenza H5N1 detections in waterfowl. These findings suggest prior exposure of wild mammals to these viruses without mortality events. Wild mammals may play an intermediary role in the mammalian adaptation of avian influenza A viruses. Therefore, ongoing surveillance of wild mammals is crucial for assessing the risk to public health.

Source: Viruses, https://www.mdpi.com/1999-4915/17/10/1388

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