Genomic diversity and evolutionary dynamics of Influenza A viruses in Colombian swine: implications for one health surveillance and control.

Influenza A viruses (IAV) impose significant respiratory disease burdens in both swine and humans worldwide, with frequent human-to-swine transmission driving viral evolution in pigs and highlighting the risk at the animal-human interface. Therefore, a comprehensive One Health approach (interconnection among human, animal, and environmental health) is needed for IAV prevention, control, and response. Animal influenza genomic surveillance remains limited in many Latin American countries, including Colombia. To address this gap, we genetically characterized 170 swine specimens from Colombia (2011-2017). Whole genome sequencing revealed a predominance of pandemic-like H1N1 lineage, with a minority belonging to H3N2 and H1N2 human seasonal-like lineage and H1N1 early classical swine lineages. Significantly, we have identified reassortant and recombinant viruses (H3N2, H1N1) not previously reported in Colombia. This suggests a broad genotypic viral diversity, likely resulting from reassortment between classical endemic viruses and new introductions established in Colombia's swine population (e.g. the 2009 H1N1 pandemic). Our study highlights the importance of a One Health approach in disease control, particularly in an ecosystem where humans are a main source of IAV to swine populations, and emphasizes the need for continued surveillance and enhanced biosecurity measures. The co-circulation of multiple subtypes in regions with high swine density facilitates viral exchange, underscoring the importance of monitoring viral evolution to inform vaccine selection and public health policies locally and globally.

Surveillance outcomes of respiratory pathogen infections during the 2021-2022 season among U.S. Military Health System beneficiaries, October 3, 2021-October 1, 2022.

The Department of Defense Global Respiratory Pathogen Surveillance Program conducts continuous surveillance for influenza, severe acute respiratory syndrome 2 (SARS-CoV-2), and other respiratory pathogens at 104 sentinel sites across the globe. These sites submitted 65,475 respiratory specimens for clinical diagnostic testing during the 2021-2022 surveillance season. The predominant influenza strain was influenza A(H3N2) (n=777), of which 99.9% of strains were in clade 3C.2a1b.2a2. A total of 21,466 SARSCoV-2-positive specimens were identified, and 12,225 of the associated viruses were successfully sequenced. The Delta variant predominated at the start of the season, until December 2021, when Omicron became dominant. Most circulating SARS-CoV-2 viruses were subsequently held by Omicron sublineages BA.1, BA.2, and BA.5 during the season. Clinical manifestation, obtained through a self-reported questionnaire, found that cough, sinus congestion, and runny nose complaints were the most common symptoms presenting among all pathogens. Sentinel surveillance can provide useful epidemiological data to supplement other disease monitoring activities, and has become increasingly useful with increasing numbers of individuals utilizing COVID-19 rapid self-test kits and reductions in outpatient visits for routine respiratory testing.

CRISPR-Based Assays for Point-of-Need Detection and Subtyping of Influenza.

The high disease burden of influenza virus poses a significant threat to human health. Optimized diagnostic technologies that combine speed, sensitivity, and specificity with minimal equipment requirements are urgently needed to detect the many circulating species, subtypes, and variants of influenza at the point of need. Here, we introduce such a method using Streamlined Highlighting of Infections to Navigate Epidemics (SHINE), a clustered regularly interspaced short palindromic repeats (CRISPR)-based RNA detection platform. Four SHINE assays were designed and validated for the detection and differentiation of clinically relevant influenza species (A and B) and subtypes (H1N1 and H3N2). When tested on clinical samples, these optimized assays achieved 100% concordance with quantitative RT-PCR. Duplex Cas12a/Cas13a SHINE assays were also developed to detect two targets simultaneously. This study demonstrates the utility of this duplex assay in discriminating two alleles of an oseltamivir resistance (H275Y) mutation as well as in simultaneously detecting influenza A and human RNAse P in patient samples. These assays have the potential to expand influenza detection outside of clinical laboratories for enhanced influenza diagnosis and surveillance.

Outbreak of influenza and SARS-CoV-2 at the Armed Forces of the Philippines Health Service Education and Training Center, September 25-October 10, 2023.

In the last week of September 2023, a surge of influenza-like illness was observed among students of the Armed Forces of the Philippines (AFP) Health Service Education and Training Center, where 48 (27 males and 21 females; age in years: mean 33, range 27-41) of 247 military students at the Center presented with respiratory symptoms. Between September 25 and October 10, 2023, all 48 symptomatic students were evaluated with real-time reverse transcription polymerase chain reaction and sequencing for both influenza and SARS-CoV-2. Thirteen (27%) students were found positive for influenza A/H3 only, 6 (13%) for SARS-CoV-2 only, and 4 (8%) were co-infected with influenza A/H3 and SARS-CoV-2. Seventeen influenza A/ H3N2 viruses belonged to the same clade, 3C.2a1b.2a.2a.3a, and 4 SARSCoV-2 sequences belonged to the JE1.1 lineage, indicating a common source outbreak for both. The influenza A/H3N2 circulating virus belonged to a different clade than the vaccine strain for 2023 (3C.2a1b.2a.2a). Only 4 students had received the influenza vaccine for 2023. In response, the AFP Surgeon General issued a memorandum to all military health institutions on October 19, 2023 that mandated influenza vaccination as a prerequisite for enrollment of students at all education and training centers, along with implementation of non-pharmaceutical interventions and early notification and testing of students exhibiting influenza-like-illness.

Global seroprevalence and prevalence of infection of influenza in dogs (Canis familiaris): A systematic review and meta-analysis.

Influenza in dogs holds considerable public health significance due to their close companionship with humans, yet several facets of this phenomenon remain largely unexplored. This study undertook a systematic review and meta-analysis of observational studies to gauge the global seroprevalence of influenza in dogs. We also assessed whether pet dogs exhibited a higher seroprevalence of influenza compared to non-pet dogs, explored seasonal variations in seroprevalence, scrutinised the design and reporting standards of existing studies, and elucidated the geographical distribution of canine influenza virus (cIV). A comprehensive analysis of 97 studies spanning 27 countries revealed that seroprevalence of various influenza strains in dogs consistently registered below 10% and exhibited relative stability over the past decade. Significantly, we noted that seroprevalence of human influenza virus was notably higher in pet dogs compared to their non-pet counterparts, whereas seroprevalence of other influenza strains remained relatively uniform among both categories of dogs. Seasonal variations in seroprevalence of cIV were not observed. In summary, our findings indicated the global circulation of cIV strains H3N2 and H3N8, with other strains primarily confined to China. Given the lack of reported cases of the transmission of cIV from dogs to humans, our findings suggest a higher risk of reverse zoonosis than zoonosis. Finally, we strongly advocate for standardised reporting guidelines to underpin future canine influenza research endeavours.

Molecular characterization of influenza virus circulating in Nepal in the year 2019.

Influenza (sometimes referred to as "flu") is a contagious viral infection of the airways in the lungs that affects a significant portion of the world's population. Clinical symptoms of influenza virus infections can range widely, from severe pneumonia to moderate or even asymptomatic sickness. If left untreated, influenza can have more severe effects on the heart, brain, and lungs than on the respiratory tract and can necessitate hospitalization. This study was aimed to investigate and characterize all types of influenza cases prevailing in Nepal and to analyze seasonal occurrence of Influenza in Nepal in the year 2019. A cross sectional, retrospective and descriptive study was carried out at National Influenza Center (NIC), National Public Health Laboratory Kathmandu Nepal for the period of one year (Jan-Dec 2019). A total of 3606 throat swab samples from various age groups and sexes were processed at the NIC. The specimens were primarily stored at 4 °C and processed using ABI 7500 RT PCR system for the identification of Influenza virus types and subtypes. Data accessed for research purpose were retrieved from National Influenza Centre (NIC) on 1st Jan 2020. Of the total 3606 patients suspected of having influenza infection, influenza viruses were isolated from 1213 (33.6%) patients with male predominance. The highest number of infection was caused by Influenza A/Pdm09 strain 739 (60.9%) followed by Influenza B 304 (25.1%) and Influenza A/H3 169 (13.9%) and most remarkable finding of this study was the detection of H5N1 in human which is the first ever case of such infection in human from Nepal. Similar to other tropical nations, influenza viruses were detected year-round in various geographical locations of Nepal. The influenza virus type and subtypes that were in circulation in Nepal were comparable to vaccine candidate viruses, which the currently available influenza vaccine may prevent.

Nanopore sequencing of influenza A and B in Oxfordshire and the United Kingdom, 2022-23.

OBJECTIVES: We evaluated Nanopore sequencing for influenza surveillance. METHODS: Influenza A and B PCR-positive samples from hospital patients in Oxfordshire, UK, and a UK-wide population survey from winter 2022-23 underwent Nanopore sequencing following targeted rt-PCR amplification. RESULTS: From 941 infections, successful sequencing was achieved in 292/388 (75 %) available Oxfordshire samples: 231 (79 %) A/H3N2, 53 (18 %) A/H1N1, and 8 (3 %) B/Victoria and in 53/113 (47 %) UK-wide samples. Sequencing was more successful at lower Ct values. Most same-sample replicate sequences had identical haemagglutinin segments (124/141, 88 %); 36/39 (92 %) Illumina vs. Nanopore comparisons were identical, and 3 (8 %) differed by 1 variant. Comparison of Oxfordshire and UK-wide sequences showed frequent inter-regional transmission. Infections were closely-related to 2022-23 vaccine strains. Only one sample had a neuraminidase inhibitor resistance mutation. 849/941 (90 %) Oxfordshire infections were community-acquired. 63/88 (72 %) potentially healthcare-associated cases shared a hospital ward with ≥ 1 known infectious case. 33 epidemiologically-plausible transmission links had sequencing data for both source and recipient: 8 were within ≤ 5 SNPs, of these, 5 (63 %) involved potential sources that were also hospital-acquired. CONCLUSIONS: Nanopore influenza sequencing was reproducible and antiviral resistance rare. Inter-regional transmission was common; most infections were genomically similar. Hospital-acquired infections are likely an important source of nosocomial transmission and should be prioritised for infection prevention and control.

[The identification of a novel reassortant H3N2 avian influenza virus based on nanopore sequencing technology and genetic characterization].

Objective: To identify a novel reassortant H3N2 avian influenza virus using nanopore sequencing technology and analyze its genetic characteristics. Methods: The positive samples of the H3N2 avian influenza virus, collected from the external environment in the farmers' market of Guangzhou, were cultured in chicken embryos. The whole genome was sequenced by targeted amplification and nanopore sequencing technology. The genetic characteristics were analyzed using bioinformatics software. Results: The phylogenetic trees showed that each gene fragment of the strain belonged to the Eurasian evolutionary branch, and the host source was of avian origin. The HA gene was closely related to the origin of the H3N6 virus. The NA gene was closely related to the H3N2 avian influenza virus from 2017 to 2020. The PB1 gene was closely related to the H5N6 avian influenza virus in Guangxi Zhuang Autonomous Region and Fujian Province from 2016 to 2022 and was not related to the PB1 gene of the H5N6 avian influenza epidemic strain in Guangzhou. The other internal gene fragments had complex sources with significant genetic diversity. Molecular characteristics indicated that the strain exhibited the molecular characteristics of a typical low pathogenic avian influenza virus and tended to bind to the receptors of avian origin. On important protein sites related to biological characteristics, this strain had mutations of PB2-L89V, PB1-L473V, NP-A184K, M1-N30D/T215A, and NS1-P42S/N205S. Conclusions: This study identified a novel reassortant H3N2 avian influenza virus by nanopore sequencing, with the PB1 gene derived from the H5N6 avian influenza virus. The virus had a low ability to spread across species, but further exploration was needed to determine whether its pathogenicity to the host was affected.

Single-virus-sensitive barcode qPCR mediated by the aggregation of gold nanoparticle probes.

Herein, we developed a gold nanoparticle (GNP)-mediated barcode qPCR strategy with a sensitivity for a single virus particle per reaction for the detection of influenza virus H3N2. The analysis of the results for pure virus and real virus samples show that GNP-mediated barcode qPCR is ∼16 times more sensitive than conventional qPCR, demonstrating the potential to reduce false negatives and improve early diagnosis of viral infections.

Association of viral loads of influenza A (H3N2) with age and care setting on presentation-a prospective study during the 2022-2023 influenza season in Spain.

OBJECTIVES: The aim of this study was to analyze the viral load (VL) using cycle threshold (Ct) in patients infected with influenza A (H3N2). METHODS: This prospective study was conducted during the 2022-2023 influenza season in sentinel, non-sentinel, and hospitalized patients of Castilla y León (Spain). Respiratory samples were obtained from nasopharyngeal swabs and analyzed by quantitative reverse transcription-polymerase chain reaction specific for influenza A (H3N2) to obtain the Ct value. RESULTS: A total of 1047 individuals were enrolled (174 [16.6%] sentinel, 200 [19.1%] non-sentinel, 673 [64.3%] hospitalized). The mean Ct value was lower in infants, young children, and in the elderly, with a sharp increase in the last from 65 years until 90 years. In addition, the lower Ct values were observed in non-sentinel patients and then in hospitalized patients, probably because non-sentinel are outpatients in the acute phase of the influenza infection. CONCLUSIONS: A higher VL (lower Ct value) is related to the extreme ages of life: children and the elderly. Furthermore, a higher VL is related with the care setting, being probably higher in outpatients because they are in the acute phase of the disease and slightly lower in hospitalized patients because they are attended during the post-acute phase.

Detection and Characterization of Influenza A Virus Endemic Circulation in Suckling and Nursery Pigs Originating from Vaccinated Farms in the Same Production System.

Inactivated influenza A virus (IAV) vaccines help reduce clinical disease in suckling piglets, although endemic infections still exist. The objective of this study was to evaluate the detection of IAV in suckling and nursery piglets from IAV-vaccinated sows from farms with endemic IAV infections. Eight nasal swab collections were obtained from 135 two-week-old suckling piglets from four farms every other week from March to September 2013. Oral fluid samples were collected from the same group of nursery piglets. IAV RNA was detected in 1.64% and 31.01% of individual nasal swabs and oral fluids, respectively. H1N2 was detected most often, with sporadic detection of H1N1 and H3N2. Whole-genome sequences of IAV isolated from suckling piglets revealed an H1 hemagglutinin (HA) from the 1B.2.2.2 clade and N2 neuraminidase (NA) from the 2002A clade. The internal gene constellation of the endemic H1N2 was TTTTPT with a pandemic lineage matrix. The HA gene had 97.59% and 97.52% nucleotide and amino acid identities, respectively, to the H1 1B.2.2.2 used in the farm-specific vaccine. A similar H1 1B.2.2.2 was detected in the downstream nursery. These data demonstrate the low frequency of IAV detection in suckling piglets and downstream nurseries from farms with endemic infections in spite of using farm-specific IAV vaccines in sows.

The evolution, pathogenicity and transmissibility of quadruple reassortant H1N2 swine influenza virus in China: A potential threat to public health.

Swine are regarded as "intermediate hosts" or "mixing vessels" of influenza viruses, capable of generating strains with pandemic potential. From 2020 to 2021, we conducted surveillance on swine H1N2 influenza (swH1N2) viruses in swine farms located in Guangdong, Yunnan, and Guizhou provinces in southern China, as well as Henan and Shandong provinces in northern China. We systematically analyzed the evolution and pathogenicity of swH1N2 isolates, and characterized their replication and transmission abilities. The isolated viruses are quadruple reassortant H1N2 viruses containing genes from pdm/09 H1N1 (PB2, PB1, PA and NP genes), triple-reassortant swine (NS gene), Eurasian Avian-like (HA and M genes), and recent human H3N2 (NA gene) lineages. The NA, PB2, and NP of SW/188/20 and SW/198/20 show high gene similarities to A/Guangdong/Yue Fang277/2017 (H3N2). The HA gene of swH1N2 exhibits a high evolutionary rate. The five swH1N2 isolates replicate efficiently in human, canine, and swine cells, as well as in the turbinate, trachea, and lungs of mice. A/swine/Shandong/198/2020 strain efficiently replicates in the respiratory tract of pigs and effectively transmitted among them. Collectively, these current swH1N2 viruses possess zoonotic potential, highlighting the need for strengthened surveillance of swH1N2 viruses.

Household Transmission of Influenza A Viruses in 2021-2022.

Importance: Influenza virus infections declined globally during the COVID-19 pandemic. Loss of natural immunity from lower rates of influenza infection and documented antigenic changes in circulating viruses may have resulted in increased susceptibility to influenza virus infection during the 2021-2022 influenza season. Objective: To compare the risk of influenza virus infection among household contacts of patients with influenza during the 2021-2022 influenza season with risk of influenza virus infection among household contacts during influenza seasons before the COVID-19 pandemic in the US. Design, Setting, and Participants: This prospective study of influenza transmission enrolled households in 2 states before the COVID-19 pandemic (2017-2020) and in 4 US states during the 2021-2022 influenza season. Primary cases were individuals with the earliest laboratory-confirmed influenza A(H3N2) virus infection in a household. Household contacts were people living with the primary cases who self-collected nasal swabs daily for influenza molecular testing and completed symptom diaries daily for 5 to 10 days after enrollment. Exposures: Household contacts living with a primary case. Main Outcomes and Measures: Relative risk of laboratory-confirmed influenza A(H3N2) virus infection in household contacts during the 2021-2022 season compared with prepandemic seasons. Risk estimates were adjusted for age, vaccination status, frequency of interaction with the primary case, and household density. Subgroup analyses by age, vaccination status, and frequency of interaction with the primary case were also conducted. Results: During the prepandemic seasons, 152 primary cases (median age, 13 years; 3.9% Black; 52.0% female) and 353 household contacts (median age, 33 years; 2.8% Black; 54.1% female) were included and during the 2021-2022 influenza season, 84 primary cases (median age, 10 years; 13.1% Black; 52.4% female) and 186 household contacts (median age, 28.5 years; 14.0% Black; 63.4% female) were included in the analysis. During the prepandemic influenza seasons, 20.1% (71/353) of household contacts were infected with influenza A(H3N2) viruses compared with 50.0% (93/186) of household contacts in 2021-2022. The adjusted relative risk of A(H3N2) virus infection in 2021-2022 was 2.31 (95% CI, 1.86-2.86) compared with prepandemic seasons. Conclusions and Relevance: Among cohorts in 5 US states, there was a significantly increased risk of household transmission of influenza A(H3N2) in 2021-2022 compared with prepandemic seasons. Additional research is needed to understand reasons for this association.

Circulation and seasonality of influenza viruses in different transmission zones in Africa.

BACKGROUND: Influenza is responsible for more than 5 million severe cases and 290,000 to 650,000 deaths every year worldwide. Developing countries account for 99% of influenza deaths in children under 5 years of age. This paper aimed to determine the dynamics of influenza viruses in African transmission areas to identify regional seasonality for appropriate decision-making and the development of regional preparedness and response strategies. METHODS: We used data from the WHO FluMart website collected by National Influenza Centers for seven transmission periods (2013-2019). We calculated weekly proportions of positive influenza cases and determined transmission trends in African countries to determine the seasonality. RESULTS: From 2013 to 2019, influenza A(H1N1)pdm2009, A(H3N2), and A(H5N1) viruses, as well as influenza B Victoria and Yamagata lineages, circulated in African regions. Influenza A(H1N1)pdm2009 and A(H3N2) highly circulated in northern and southern Africa regions. Influenza activity followed annual and regional variations. In the tropical zone, from eastern to western via the middle regions, influenza activities were marked by the predominance of influenza A subtypes despite the circulation of B lineages. One season was identified for both the southern and northern regions of Africa. In the eastern zone, four influenza seasons were differentiated, and three were differentiated in the western zone. CONCLUSION: Circulation dynamics determined five intense influenza activity zones in Africa. In the tropics, influenza virus circulation waves move from the east to the west, while alternative seasons have been identified in northern and southern temperate zones. Health authorities from countries with the same transmission zone, even in the absence of local data based on an established surveillance system, should implement concerted preparedness and control activities, such as vaccination.

Influenza A(H3N2) Outbreak on a University Campus - Michigan, October-November 2021.

On November 10, 2021, the Michigan Department of Health and Human Services (MDHHS) was notified of a rapid increase in influenza A(H3N2) cases by the University Health Service (UHS) at the University of Michigan in Ann Arbor. Because this outbreak represented some of the first substantial influenza activity during the COVID-19 pandemic, CDC, in collaboration with the university, MDHHS, and local partners conducted an investigation to characterize and help control the outbreak. Beginning August 1, 2021, persons with COVID-19-like* or influenza-like illness evaluated at UHS received testing for SARS-CoV-2, influenza, and respiratory syncytial viruses by rapid multiplex molecular assay.† During October 6-November 19, a total of 745 laboratory-confirmed influenza cases were identified.§ Demographic information, genetic characterization of viruses, and influenza vaccination history data were reviewed. This activity was conducted consistent with applicable federal law and CDC policy.¶.

No evidence of SARS-CoV-2 in hospitalized patients with severe acute respiratory syndrome in five Italian hospitals from 1st November 2019 to 29th February 2020.

BACKGROUND: On 9th January 2020, China CDC reported a novel coronavirus (later named SARS-CoV-2) as the causative agent of the coronavirus disease 2019 (COVID-19). Identifying the first appearance of virus is of epidemiological importance to tracking and mapping the spread of SARS-CoV-2 in a country. We therefore conducted a retrospective observational study to detect SARS-CoV-2 in oropharyngeal samples collected from hospitalized patients with a Severe Acute Respiratory Infection (SARI) enrolled in the DRIVE (Development of Robust and Innovative Vaccine Effectiveness) study in five Italian hospitals (CIRI-IT BIVE hospitals network) (1st November 2019 - 29th February 2020). OBJECTIVES: To acquire new information on the real trend in SARS-CoV-2 infection during pandemic phase I and to determine the possible early appearance of the virus in Italy. MATERIALS AND METHODS: Samples were tested for influenza [RT-PCR assay (A/H1N1, A/H3N2, B/Yam, B/Vic)] in accordance with the DRIVE study protocol. Subsequently, swabs underwent molecular testing for SARS-COV-2. [one-step real-time multiplex retro-transcription (RT) PCR]. RESULTS: In the 1683 samples collected, no evidence of SARS-CoV-2 was found. Moreover, 28.3% (477/1683) of swabs were positive for influenza viruses, the majority being type A (358 vs 119 type B). A/H3N2 was predominant among influenza A viruses (55%); among influenza B viruses, B/Victoria was prevalent. The highest influenza incidence rate was reported in patients aged 0-17 years (40.3%) followed by those aged 18-64 years (24.4%) and ≥65 years (14.8%). CONCLUSIONS: In Italy, some studies have shown the early circulation of SARS-CoV-2 in northern regions, those most severely affected during phase I of the pandemic. In central and southern regions, by contrast no early circulation of the virus was registered. These results are in line with ours. These findings highlight the need to continue to carry out retrospective studies, in order to understand the epidemiology of the novel coronavirus, to better identify the clinical characteristics of COVID-19 in comparison with other acute respiratory illnesses (ARI), and to evaluate the real burden of COVID-19 on the healthcare system.

Circulation patterns of human seasonal Influenza A viruses in Chile before H1N1pdm09 pandemic.

Understanding the diversity and circulation dynamics of seasonal influenza viruses is key to public health decision-making. The limited genetic information of pre-pandemic seasonal IAVs in Chile has made it difficult to accurately reconstruct the phylogenetic relationships of these viruses within the country. The objective of this study was to determine the genetic diversity of pre-pandemic human seasonal IAVs in Chile. We sequenced the complete genome of 42 historic IAV obtained between 1996 and 2007. The phylogeny was determined using HA sequences and complemented using other segments. Time-scale phylogenetic analyses revealed that the diversity of pre-pandemic human seasonal IAVs in Chile was influenced by continuous introductions of new A/H1N1 and A/H3N2 lineages and constant viral exchange between Chile and other countries every year. These results provide important knowledge about genetic diversity and evolutionary patterns of pre-pandemic human seasonal IAVs in Chile, which can help design optimal surveillance systems and prevention strategies. However, future studies with current sequences should be conducted.

Characterization of Canine Influenza Virus A (H3N2) Circulating in Dogs in China from 2016 to 2018.

Avian H3N2 influenza virus follows cross-host transmission and has spread among dogs in Asia since 2005. After 2015-2016, a new H3N2 subtype canine influenza epidemic occurred in dogs in North America and Asia. The disease prevalence was assessed by virological and serological surveillance in dogs in China. Herein, five H3N2 canine influenza virus (CIV) strains were isolated from 1185 Chinese canine respiratory disease samples in 2017-2018; these strains were on the evolutionary branch of the North American CIVs after 2016 and genetically far from the classical canine H3N2 strain discovered in China before 2016. Serological surveillance showed an HI antibody positive rate of 6.68%. H3N2 was prevalent in the coastal areas and northeastern regions of China. In 2018, it became the primary epidemic strain in the country. The QK01 strain of H3N2 showed high efficiency in transmission among dogs through respiratory droplets. Nevertheless, the virus only replicated in the upper respiratory tract and exhibited low pathogenicity in mice. Furthermore, highly efficient transmission by direct contact other than respiratory droplet transmission was found in a guinea pig model. The low-level replication in avian species other than ducks could not facilitate contact and airborne transmission in chickens. The current results indicated that a novel H3N2 virus has become a predominant epidemic strain in dogs in China since 2016 and acquired highly efficient transmissibility but could not be replicated in avian species. Thus, further monitoring is required for designing optimal immunoprophylactic tools for dogs and estimating the zoonotic risk of CIV in China.

The first epidemiological and virological influenza surveillance in the Republic of Guinea revealed the predominance of influenza A/H3N2 and B Victoria viruses.

Little is known about respiratory viruses infection in Guinea. Influenza surveillance has not been implemented in Guinea mainly because of the paucity of laboratory infrastructure and capacity. This paper presents the first influenza surveillance data in Guinea.Swabs were obtained from August 2018 through December 2019 at influenza sentinel sites and transported to the Institut National de Santé Publique for testing. Ribonucleic acid was extracted and tested for the presence of influenza A and B by real-time reverse transcription-polymerase chain reaction (RT-PCR). Positive samples were further characterised to determine the subtypes and lineages of influenza viruses.A total of 862 swabs were collected and tested. Twenty-three per cent of samples tested positive for influenza A and B viruses. Characterisation of positive specimens identified influenza A/H1N1pmd09 (2.5%), influenza A/H3N2 (57.3%), influenza B/Victoria lineage (36.7%) and 7 (3.5%) influenza B with undetermined lineage. Influenza B virus activity clustered in August through November while influenza A/H3N2 displayed two clusters of activities that appeared in May through August and November through December.For the first time in Guinea, the epidemiology, diversity and period of circulation of influenza viruses were studied. The results indicate the predominance and the periods of activities of influenza B Victoria lineage and influenza A/H3N2 which are important information for preventive strategies. It is warranted to extend the influenza surveillance to other parts of Guinea to better understand the epidemiology of the viruses and monitor the emergence of influenza strains with pandemic potential.

Fatal case of simply influenza A (H3N2)-associated encephalitis in immunocompetent patient.

Influenza virus-associated encephalopathy/encephalitis is a rare entity in adults that can lead to severe neurological sequelae and even death. The clinical presentation can be quite diverse. This absence of a typical presentation along with the difficulty detecting the virus in the cerebrospinal fluid represents a diagnostic challenge. We present the case of a 79-year-old male with sudden onset of decreased consciousness and signs of right hemisphere damage. The presence of influenza A (H3N2) virus in respiratory sample along with compatible findings in cranial magnetic resonance led to the diagnosis. The patient died without responding to treatment with antivirals and immunomodulators and the anatomopathological study did not detect infectious agent. Early diagnostic suspicion is essential to establish adequate treatment and improve the prognosis.