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Situation at a glance Between 1 January and 31 December 2024, a cumulative total of 151 Zika virus disease (ZVD) cases were reported from three states in India ( Gujarat, Karnataka, and Maharashtra states). Maharashtra State reported a cumulative total of 140 ZVD cases through the Integrated Disease Surveillance Programme (IDSP). Additionally, Karnataka and Gujarat states reported ten and one cases , respectively, in 2024. As of 31 December 2024, no cases of microcephaly and/or Guillain-Barre syndrome (GBS) associated with this outbreak have been reported. Zika virus (ZIKV) is transmitted to humans by the bite of an infected Aedes mosquito . Zika virus is also transmitted from mother to fetus during pregnancy, as well as through sexual contact, transfusion of blood and blood products, and possibly through organ transplantation. There is no specific treatment available for Zika virus infection or disease. Description of the situation Between 1 January and 31 December 2024, a cumulative ...

Abstract Viral infections are characterized by dispersal from an initial site to secondary locations within the host. How the resultant spatial heterogeneity shapes within-host genetic diversity and viral evolutionary pathways is poorly understood. Here, we show that virus dispersal within and between the nasal cavity and trachea maintains diversity and is therefore conducive to adaptive evolution , whereas dispersal to the lungs gives rise to population heterogeneity . We infected ferrets either intranasally or by aerosol with a barcoded influenza A/California/07/2009 (H1N1) virus . At 1, 2, or 4 days postinfection, dispersal was assessed by collecting 52 samples from throughout the respiratory tract of each animal. Irrespective of inoculation route, barcode compositions across the nasal turbinates and trachea were similar and highly diverse, revealing little constraint on the establishment of infection in the nasal cavity and descent through the trachea. Conversely, infection of the ...

Abstract Early investigation revealed a reduced risk of SARS-CoV-2 infection among social contacts of COVID-19 vaccinated individuals, referred to as indirect protection. However, indirect protection from SARS-CoV-2 infection-acquired immunity and its comparative strength and durability to vaccine-derived indirect protection in the current epidemiologic context of high levels of vaccination, prior infection, and novel variants are not well characterized. Here, we show that both vaccine-derived and infection-acquired immunity independently yield indirect protection to close social contacts with key differences in their strength and waning. Analyzing anonymized SARS-CoV-2 surveillance data from 9,625 residents in California state prisons from December 2021 to December 2022, we find that vaccine-derived indirect protection against Omicron SARS-CoV-2 infection is strongest within three months of COVID-19 vaccination [30% (95% confidence interval: 20–38%)] with subsequent modest protection....

ABSTRACT The evolution of SARS-CoV-2 pathogenicity has been a major focus of attention. However, the determinants of pathogenicity are still unclear. Various hypotheses have attempted to elucidate the mechanisms underlying the evolution of viral pathogenicity , but a definitive conclusion has yet to be reached. Here, we review the potential impact of all proteins in SARS-CoV-2 on the viral pathogenic process and analyze the effects of their mutations on pathogenicity evolution. We aim to summarize which virus-encoded proteins are crucial in influencing viral pathogenicity, defined as disease severity following infection. Mutations in these key proteins, which are the virulence factors in SARS-CoV-2, may be the driving forces behind the evolution of viral pathogenicity. Mutations in the S protein can impact viral entry and fusogenicity . Mutations in proteins such as NSP2, NSP5, NSP14, and ORF7a can alter the virus’s ability to suppress host protein synthesis and innate immunity . Mutat...

The State Food and Veterinary Service of the Republic of Lithuania would like to inform you about an outbreak of high pathogenicity avian influenza (HPAI) on a laying hens establishment in total 9 aviaries, 246,387 in total. On the same day then suspicion was received, officially appointed veterinarians visited the farm, samples of dead hens were taken monitoring for Avian influenza, and Newcastle disease and sent to the National Institute for Food and Veterinary Risk Assessment (National Reference Laboratory) for avian influenza testing. Temporary restrictions were imposed on the farm immediately, pending laboratory results. Highly pathogenic avian influenza was confirmed in all samples and the H5N1 subtype was identified. {Farm is located in Klaipedos Region.} Source: WOAH,  https://wahis.woah.org/#/in-review/6220 _____

Abstract Influenza A viruses (IAV) are likely candidates for pandemics . This report summarizes the results of the Swiss national program for surveillance of influenza viruses in pigs and transmissions to humans between 2010 and 2022. Challenges and optimization options in the program are discussed. Nasal swabs or lung tissue samples from pigs with influenza-like signs (e.g. fever, cough) were screened by real-time RT-PCR for swine influenza virus (SIV) genomes, including that of the 2009 pandemic strain A(H1N1)pdm09; positive samples were subtyped for H1, N1, H3 and N2 by RT-PCR and Sanger sequencing. In parallel, humans with influenza-like symptoms and recent contact to diseased pigs were asked to self-sample themselves with a nasal swab. Human swabs were tested for IAV and positive swabs further subtyped to identify potential cross-species transmission between swine and humans. In the pigs, SIV was detected in 375 of 674 farm visits . H1N1 is the only subtype detected in Swiss pigs ...

Abstract We present a stochastic metapopulation transmission model that simulates the spread of H5N1 avian influenza through individual dairy cows in 35,974 dairy herds in the continental United States . Transmission is enabled through the movement of cattle between herds , as indicated from Interstate Certificates of Veterinary Inspection (ICVI) data. We estimate the rates of under-reporting by state and present the anticipated rates of positivity for cattle tested at the point of exportation over time. We investigate the likely impact of intervention methods to date on the underlying epidemiological dynamics, demonstrating that current interventions have had insufficient impact , preventing only a mean 175.2 reported outbreaks. Our model predicts that the majority of the disease burden is, as of January 2025, concentrated within West Coast states , due to the network of cattle movements and distribution of the respective dairy populations . We quantify the extent of uncertainty in th...

 A wild mute swan in Alytaus Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6219 _____

ABSTRACT Current influenza vaccination approaches protect against specific viral strains, but do not consistently induce broad and long-lasting protection to the diversity of circulating influenza viruses. Single-cycle viruses delivered to the respiratory tract may offer a promising solution as they safely express a diverse array of viral antigens by undergoing just one round of cell infection in their host and stimulate broadly protective resident memory T-cell responses in the lung. We have previously developed a vaccine candidate called S-FLU , which is limited to a single cycle of infection by inactivation of the hemagglutinin signal sequence and induces a broadly cross-reactive T-cell response and antibodies to neuraminidase, but fails to induce neutralizing antibodies to hemagglutinin after intranasal administration. This study describes the development of CLEARFLU , a derivative of S-FLU, which is designed to add a neutralizing antibody response to hemagglutinin. In contrast to ...

New human cases {2}:  From 13 December 2024 to 20 January 2025, the detection of influenza A(H5) virus in five humans , influenza A( H9N2 ) virus in two humans , and influenza A( H10N3 ) virus in one human were reported officially. Additionally, five human cases of infection with influenza A(H5) viruses were detected.   Circulation of influenza viruses with zoonotic potential in animals :  High pathogenicity avian influenza (HPAI) events in poultry and non-poultry continue to be reported to the World Organisation for Animal Health (WOAH).{3} The Food and Agriculture Organization of the United Nations (FAO) also provides a global update on avian influenza viruses with pandemic potential.{4}   Risk assessment {5}:  Based on information available at the time of the risk assessment , the overall public health risk from currently known influenza viruses at the human-animal interface has not changed remains low . Sustained human to human transmission has not...

FAO calls for increased vigilance and preparedness for avian influenza (AI) during the traditional New Year festivities that will take place across Asia on the week of 27 January 2025 . In the past year, outbreaks of AI have continued to be reported in domestic poultry, wild birds and mammals in Asia . Several AI virus subtypes including H5N1, H5N2, H5N3, H5N5, H5N6, H5N8, H7N3, H7N6, H7N8, H7N9, H10N5 , and H3N2 are currently well-established in both wild and domestic bird populations in the region. In addition, subtype H5N1 subclade 2.3.4.4b continues to circulate in both wild and domestic birds worldwide. Highly pathogenic avian influenza (HPAI) can lead to heavy losses for the poultry industry, in particular to the livelihoods of vulnerable small-scale producers . Poultry trade and related activities play a key role in AI spread and amplification in domestic bird populations, including the trade of infected live poultry and their products, handling or slaughtering infected poultry,...

 Wild Cranes in Rajasthan State. Source: WOAH,  https://wahis.woah.org/#/in-review/6217 _____

UKHSA has confirmed a case of influenza A(H5N1) in a person in the West Midlands region. Bird-to-human transmission of avian influenza is rare and has previously occurred a small number of times in the UK . The person acquired the infection on a farm , where they had close and prolonged contact with a large number of infected birds. The risk to the wider public continues to be very low. The individual is currently well and was admitted to a High Consequence Infectious Disease (HCID) unit. The birds were infected with the DI.2 genotype , one of the viruses known to be circulating in birds in the UK this season. This is different to strains circulating among mammals and birds in the US. Although there has been no demonstrated human-to-human transmission despite extensive recent surveillance of influenza A(H5N1), UKHSA has been tracing all individuals who have been in contact with the confirmed case of avian influenza. Those at highest risk of exposure have been offered antiviral treatmen...

Abstract Pigs serve as a mixing vessel for influenza viruses and can independently promote the emergence of pandemic strains in humans. During our surveillance of pig populations from 2021 to 2023 in China , 11 H1 subtype swine influenza viruses (SIVs) were isolated. All viruses were reassortants , possessing internal genes of identical origins ( PB2, PB1, PA, NP, M : pdm09/H1N1 origin, NS : North American triple reassortant origin). The H1N1 isolates were all the dominant G4 EA H1N1 viruses in China. Two H1N2 isolates carried early human pdm09/H1N1 HA genes, suggesting a possible pig-to-human transmission route. Mutations that dictate host range specificity were identified in all isolates, a phenomenon which may enhance the affinity to human receptors. These H1 subtype viruses effectively replicated both in vivo and in vitro without prior adaptation and exhibited different pathogenicity and growth characteristics. Some of the H1 viruses were even found to cause lethal infections in mi...

Summary The 2024 Nipah outbreak in Kerala, India —its fifth in six years—and the recurring annual outbreaks in Bangladesh underscore the persistent threat posed by the Nipah virus (NiV) in the region. With a high mortality rate, human-to-human transmission potential , and the widespread presence of Pteropus bats , the natural reservoir, NiV remains a significant epidemic threat . Despite being a WHO priority pathogen , there has been no systematic effort to improve patient care for NiVD, leading to consistently poor outcomes . Current care relies on supportive measures and the ‘ compassionate use ’ of unapproved drugs like ribavirin and remdesivir . Drugs used ‘off-label’ during outbreaks can become the ‘standard of care’ without robust evidence of their safety or efficacy, complicating the testing of new therapies and perpetuating uncertainty about their true effectiveness. To improve NiVD care, we propose four key strategies: 1) Enhance early case detection , 2) optimize supportive c...

{Excerpt} Highly pathogenic avian influenza (HPAI) subtype H5Nx viruses of the A/Goose/Guangdong/1/1996 (Gs/Gd) lineage have led to substantial economic losses within the poultry industry and represent an ongoing public health threat (1). The Gs/Gd lineage H5 viruses not only have evolved into 10 primary clades 0–9 with their subclades but are also reassorted with other influenza A viruses (2–4). Notably, since 2020, clade 2.3.4.4b HPAI H5N1 viruses have caused outbreaks across a broad geographic range, including Asia, Europe, Africa, North America, South America, and Antarctica (5–7). The infections of HPAI H5N1 viruses in mammals including wild, domestic, and humans underscore the potential zoonotic risk and pandemic potential of these evolving H5 viruses (8). (...) Source: Frontiers in Veterinary Sciences,  https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2024.1526118/full ____

Highly pathogenic avian influenza (HPAI) H5N9, Eurasian lineage goose/Guangdong clade 2.3.4.4b and HPAI H5N1 clade 2.3.4.4b were confirmed in a commercial duck premises in Merced County, CA . This is the first confirmed case of HPAI H5N9 in poultry in the United States. The USDA Animal and Plant Health Inspection Service (APHIS), in conjunction with State Animal Health and Wildlife Officials, are conducting comprehensive epidemiological investigations and enhanced surveillance in response to the HPAI related events. Source: WOAH,  https://wahis.woah.org/#/in-review/6201 _____

Abstract Bussuquara virus (BSQV) was first discovered in the Brazilian Amazon in 1956 . It is an arthropod-borne virus (arbovirus) in the genus Orthoflavivirus , family Flaviviridae . Since its discovery, BSQV has been sporadically detected across the South ( Brazil, Columbia, and Argentina ) and Central ( Panama and Mexico ) America and the Caribbean ( Grenada ), but there is minimal BSQV surveillance due to limited public health awareness and a lack of specific or sensitive diagnostics. BSQV exposure has been reported in a wide range of host and vector species , including humans . Little information is available in the literature and herein we summarize the published historical findings on BSQV and suggest a pathway for future studies to better understand its potential emergence into human populations. Source: Viruses,  https://www.mdpi.com/1999-4915/17/2/183 _____

Abstract The generation time , representing the interval between infections in primary and secondary cases , is essential for understanding and predicting the transmission dynamics of seasonal influenza , including the real-time effective reproduction number (Rt). However, comprehensive generation time estimates for seasonal influenza, especially since the 2009 influenza pandemic, are lacking. We estimated the generation time utilizing data from a 7-site case-ascertained household study in the United States over two influenza seasons, 2021/2022 and 2022/2023. More than 200 individuals who tested positive for influenza and their household contacts were enrolled within 7 days of the first illness in the household. All participants were prospectively followed for 10 days, completing daily symptom diaries and collecting nasal swabs, which were then tested for influenza via RT-PCR. We analyzed these data by modifying a previously published Bayesian data augmentation approach that imputes in...

Abstract Introduction :  Since the dawn of the new millennium, Candida species have been increasingly implicated as a cause of both healthcare-associated as well as opportunistic yeast infections , due to the widespread use of indwelling medical devices , total parenteral nutrition , systemic corticosteroids , cytotoxic chemotherapy , and broad-spectrum antibiotics. Candida tropicalis is a pathogenic Candida species associated with considerable morbidity, mortality , and drug resistance issues on a global scale. Methodology :  We report a case of a 43-year-old man who was admitted to our hospital for further management of severe coronavirus disease 2019 (COVID-19) pneumonia . During his stay in the ward, he received systemic corticosteroids for a total duration of 32 days. A broad-spectrum antibiotic (piperacillin-tazobactam) was also given due to copious amounts of tracheostomy secretions . Results :  The patient’s fever recurred following an afebrile interval of 11 days...