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

  Abstract Background   The ongoing H5N1 panzootic in mammals has amplified zoonotic pathways to facilitate human infection . Characterising key epidemiological parameters for H5N1 is critical should it become widespread.  Aim   To identify and estimate critical epidemiological parameters for H5N1 from past and current outbreaks, and to compare their characteristics with human influenza subtypes and the 2003 Netherlands H7N7 outbreak.  Methods   We searched PubMed, Embase, and Cochrane Library for systematic reviews reporting parameter estimates from primary data or meta-analyses. To address gaps, we searched PubMed and Google Scholar for studies of any design providing relevant estimates. We estimated the basic reproduction number for the recent outbreak in the United States (US) and the 2003 Netherlands H7N7 outbreak. In addition we estimated the serial interval for H5N1 using data from previous household clusters in Indonesia. We also applied a branching...

#Italy, Integrated #Surveillance for #WNV & #Usutu Virus - Weekly Bulletin No. 5 (August 14 '25): 102 new human cases

  {Summary} • During current week (7-13 August '25), 102 new cases of human infection with West Nile Virus have been reported;  • Total Number of Confirmed Cases so far this season have risen to 275 (they were 173 in the last report);  -- among these:  - 126 were West Nile Neuroinvasive Disease (WNND): 6 in Piedmont, 7 Lombardy, 5 Veneto, 1 FriuliVenezia Giulia, 4 Emilia-Romagna, 47 Latium, 50 Campania, 1 Basilicata, 3 Calabria, 2 Sardinia,  - 20 asymptomatic cases among blood donors ;  - 125 West Nile Fever cases,  - 2 asymptomatic cases and  - 2 unspecified cases.  • So far, 19 fatal cases were reported: 1 in Piedmont, 1 Lombardy, 8 Latium, 8 Campania, 1 Calabria.  -- The Case-Fatality Rate of WNND cases is at 15,1% (during 2018 it was 20%, in 2024 14%).  • No confirmed cases of Usutu Virus human infection were reported during current week.  (...) Source: High Institute of Health,  https://www.epicentro.iss.it/westnile/...

Avian #Influenza #Surveillance Among Migratory #Birds, #Poultry, and #Humans Around Nansi Lake, #China, 2021–2024

Abstract Avian influenza A viruses (AIVs) pose a significant pandemic threat due to their cross-species transmission potential . However, AIV surveillance at the critical “ migratory birds–poultry-exposed population ” interface remains limited. Between 2021 and 2024, we implemented a prospective One Health surveillance program around Nansi Lake , monitoring AIVs in migratory birds, poultry, and environmental samples, as well as serological investigations against representative AIVs among migratory birds or poultry-exposed subjects. AIVs were detected in 2.1% (30/1417) of migratory bird samples and 10.2% (100/978) of poultry samples . Among these, we identified ten highly pathogenic avian influenza (HPAI) H5 subtype viruses, one HPAI H7N9 virus, and five low pathogenic avian influenza (LPAI) H9N2 viruses. Phylogenetic analysis revealed evidence of frequent genomic reassortment events involving H5 subtype viruses among migratory birds, poultry, and humans . Serological investigation also...

#Italy, #WNV and #Usutu Virus Weekly #Surveillance #Bulletin No. 4, July 7 '25: 84 new confirmed cases (ISS)

{Summary} -- Since the last update (July 31), eighty-four new confirmed cases of human infection with West Nile Virus have been reported.  -- Since the start of epidemic season, there were 173 confirmed WNV cases, of which:  - 72 were West Nile Neuroinvasive Disease (WNND): (2 in Piedmont, 2 Lombardy, 4 Veneto, 1 Friuli-Venezia Giulia, 2 Emilia-Romagna, 37 Latium, 21 Campania, 1 Basilicata, 1 Sardegna),  - 14 were asymptomatic cases in blood donors ,  - 85 were West Nile Fever cases,  - 1 was an asymptomatic case  -- Among the confirmed cases, there were eleven fatalities : 1 in Piedmont, 4 Latium, 6 .  - The case-fatality rate among WNND cases is at 15% (during 2018 season it was 20%, whereas in 2024 it was 14%).  -- No new confirmed cases of Usutu Virus human infection have been reported during current surveillance week. (...) Source: High Institute of Health,  https://www.epicentro.iss.it/westnile/bollettino/Bollettino_WND_2025_04.pdf ____...

#Nipah virus #infection - #India (#WHO D.O.N., August 6 '25)

Situation at a glance Between 17 May and 12 July 2025, the Information and Public Relations Department, Government of Kerala informed through a series of official press releases about four confirmed cases , including two deaths , due to Nipah virus (NiV) infection in two districts of Kerala State.  NiV infection is a bat-borne disease transmitted to humans through infected animals (such as bats or pigs), contaminated food or, less commonly, through close contact with infected individuals.  Since 1998 NiV outbreaks have been reported in Bangladesh, India, Malaysia , the Philippines , and Singapore .  In India, NiV infections have occurred multiple times since 2001 with outbreaks in West Bengal State in 2001 and 2007, and in Kerala State regularly since 2018.  Since 2018, Kerala has reported a total of nine NiV outbreaks . While the state has a strong healthcare system and improved infection control measures since 2023, it is advisable to maintain strong preparedness a...

Detection of #Hemagglutinin #H5 #Influenza A Virus #RNA and Model of Potential Inputs in an Urban #California #Sewershed

Abstract In 2024, highly pathogenic avian influenza A H5N1 caused outbreaks in wild birds, poultry, cows, and other mammals in the United States with 61 human cases also reported by the CDC. Detection of influenza A H5 RNA in wastewater has been previously reported in sewersheds in Texas and North Carolina with nearby impacted dairy herds following the emergence of H5N1 in dairy cows. Here, we conduct retrospective testing of total influenza A and H5 hemagglutinin genes in wastewater as well as present and apply new assays for detection of H1 and H3 genes across a respiratory virus season in an urban California sewershed from September 2023 to May 2024. Total influenza A, H1, and H3 were regularly detected, while H5 was first detected in March . We developed a model that uses Monte Carlo simulations and previously published parameters to estimate the numbers of infected people, poultry, wild birds, or liters of H5-contaminated milk required to result in measured H5 concentrations in wa...

A Phylogeny-Informed Mathematical #Modeling of #H5N1 #Transmission Dynamics and Effectiveness of #Control Measures

Abstract The highly pathogenic avian influenza (HPAI) subtype H5N1 is a severe viral disease which continues to pose a significant threat to public health and a rigorous understanding of its transmission dynamics across its major pathways is essential for developing effective control strategies . Phylogenetic analysis suggests that H5N1 spillover occurs primarily between wild and domestic birds . However, increasing contact between these species and humans increases the risk of zoonotic transmission . In this work, we develop a mathematical model to examine the transmission dynamics of H5N1 and evaluate the effectiveness of proposed control measures. The model employs a compartmental framework that includes human, domestic, and wild bird populations. We then use this model to estimate the basic reproduction number for each population group and perform a sensitivity analysis to assess the contribution of the parameters to the spread of the disease. Numerical simulations are also conduct...

#Cambodia reports 14th #human case of #H5N1 avian #influenza virus infection in 2025

PHNOM PENH, July 29 (Xinhua) -- A 26-year-old man from northwest Cambodia's Siem Reap province has been confirmed for H5N1 human avian influenza, raising the number of the cases to 14 so far this year, the Ministry of Health said in a statement on Tuesday. "A laboratory result from the National Institute of Public Health showed on July 26 that the man was positive for H5N1 virus," the statement said. "The patient has the symptoms of fever, cough, sore throat, stomach ache , and breathing difficulty, and is currently being rescued by a team of doctors," it added. The victim lives in Kravann village of Siem Reap city. "Investigations revealed that there were dead chickens near the patient's house and he also culled and plucked chickens three days before he fell ill," the statement said. Health authorities are looking into the source of the infection and are examining any suspected cases or people who have been in contact with the victim in order to p...

Updated joint #FAO / #WHO / #WOAH public #health #assessment of recent #influenza #H5 virus #events in animals and people (July 28 '25)

  Key points   -- At the present time , based on available information, FAO-WHO-WOAH assess the global public health risk of influenza A(H5) viruses to be low , while the risk of infection for occupationally or frequently exposed (e.g., with backyard poultry) persons is low to moderate depending on the risk mitigation and hygiene measures in place and the local avian influenza epidemiological situation.  -- Transmission between animals continues to occur and, to date, a growing yet still limited number of human infections are being reported. Although additional human infections associated with exposure to infected animals or contaminated environments are expected to occur, the overall public health impact of such infections at a global level , at the present time, is considered minor . The assessment could change if and when additional epidemiological or virological information becomes available.  -- This risk assessment from FAO, WHO and WOAH updates the assessment ...