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Aims: This study aimed to identify exposure to human, swine, and avian influenza A virus subtypes in rural companion and hunting dogs, backyard pigs, and feral pigs. Methods and Results: The study took place in a region of southeastern Mexico where the sampled individuals were part of backyard production systems in which different domestic and wild species coexist and interact with humans. We collected blood samples from pigs and dogs at each of the sites. We used a nucleoprotein enzyme‐linked immunosorbent assay to determine the exposure of individuals to influenza A virus. Haemagglutination inhibition was performed on the positive samples to determine the subtypes to which they were exposed. For data analysis, a binomial logistic regression model was generated to determine the predictor variables for the seropositivity of the individuals in the study. We identified 11 positive individuals: three backyard pigs, four companion dogs, and four hunting dogs. The pigs tested positive for H1N1 and H1N2. The dogs were positive for H1N1, H1N2, and H3N2. The model showed that dogs in contact with backyard chickens are more likely to be seropositive for influenza A viruses. Conclusions: We demonstrated the essential role hunting dogs could play as intermediate hosts and potential mixing vessel hosts when exposed to human and swine‐origin viral subtypes. These results are relevant because these dogs interact with domestic hosts and humans in backyard systems, which are risk scenarios in the transmission of influenza A viruses. Therefore, it is of utmost importance to implement epidemiological surveillance of influenza A viruses in backyard animals, particularly in key animals in the transmission of these viruses, such as dogs and pigs. [ABSTRACT FROM AUTHOR]

Influenza A viruses (IAVs) are characterized by having a segmented genome, low proofreading polymerases, and a wide host range. Consequently, IAVs are constantly evolving in nature causing a threat to animal and human health. In 2009 a new human pandemic IAV strain arose in Mexico because of a reassortment between two strains previously circulating in pigs; Eurasian "avian-like" (EA) swine H1N1 and "human-like" H1N2, highlighting the importance of swine as adaptation host of avian to human IAVs. Nowadays, although of limited use, a trivalent vaccine, which include in its formulation H1N1, H3N2, and, H1N2 swine IAV (SIAV) subtypes, is one of the most applied strategies to reduce SIAV circulation in farms. Protection provided by vaccines is not complete, allowing virus circulation, potentially favoring viral evolution. The evolutionary dynamics of SIAV quasispecies were studied in samples collected at different times from 8 vaccinated and 8 nonvaccinated pigs, challenged with H1N2 SIAV. In total, 32 SIAV genomes were sequenced by next-generation sequencing, and subsequent variant-calling genomic analysis was carried out. Herein, a total of 364 de novo single nucleotide variants (SNV) were found along all genetic segments in both experimental groups. The nonsynonymous substitutions proportion found was greater in vaccinated animals suggesting that H1N2 SIAV was under positive selection in this scenario. The impact of each substitution with an allele frequency greater than 5% was hypothesized according to previous literature, particularly in the surface glycoproteins hemagglutinin and neuraminidase. The H1N2 SIAV quasispecies evolution capacity was evidenced, observing different evolutionary trends in vaccinated and nonvaccinated animals. [ABSTRACT FROM AUTHOR]

The burden of influenza in Mexico has been high. We aimed to characterize its epidemiological patterns before and during the coronavirus disease 2019 (COVID-19) pandemic. A retrospective cohort study was conducted and 5652 PCR-confirmed cases of influenza (October 2019–April 2022) were analyzed. The highest incidence (144 per million) was observed in December 2019 and rapidly decreased right before the start of the pandemic (February 2020). No cases were documented in the 2020–2021 season, and infections reemerged at a low level (8 per million) in December 2021. The case-fatality rates were around 5% in both seasons (p = 0.591). The dominant strains were AH1N1 and AH3N2 in the 2019–2020 and 2021–2022 seasons, respectively. In multiple analysis, males and older patients were at increased risk of a fatal outcome. Flu vaccination and infection by B lineages (vs. AH1N1) showed a protective effect. Our results suggest that the spread of the influenza virus reemerged in the 2021–2022 season when the SARS-CoV-2 Omicron variant (B.1.1.529) was dominant. Efforts focusing on the prevention of transmission of respiratory viral pathogens, together with flu vaccination, may be useful to reduce the risk of an influenza outbreak. [ABSTRACT FROM AUTHOR]

Erythrostemon yucatanensis (Greenm.) Gagnon & GP Lewis is a legume tree native to and widely distributed in southeast Mexico, where its branches are used in traditional medicine. An in vitro evaluation of the antiviral activity of extracts and fractions from the leaves, stem bark and roots against two strains of the AH1N1 influenza virus was performed, leading to the identification of bioactive compounds in this medicinal plant. In a cytopathic effect reduction assay, the fractions from the leaves and stem bark were the active elements at the co-treatment level. These were further fractionated based on their hemagglutination inhibition activity. The analysis of spectroscopy data identified a combination of phytosterols (β-sitosterol, stigmasterol and campesterol) in the stem bark active fraction as the main anti-hemagglutinin binding components, while 5-hydroxy-2(2-hydroxy-3,4,5-trimethoxyphenyl)-7-metoxi-4H(chromen-4-ona), which was isolated from the leaf extracts, showed a weak inhibition of viral hemagglutinin. Time of addition experiments demonstrated that the mixture of sterols had a direct effect on viral particle infectivity at the co-treatment level (IC50 = 3.125 µg/mL). This effect was also observed in the virus plaque formation inhibition assay, where the mixture showed 90% inhibition in the first 20 min of co-treatment at the same concentration. Additionally, it was found using qRT-PCR that the NP copy number was reduced by 92.85% after 60 min of co-treatment. These results are the first report of components with anti-hemagglutinin binding activity in the genus Erythrostemon sp. [ABSTRACT FROM AUTHOR]

The most widely used class of antivirals available for Influenza treatment are the neuraminidase inhibitors (NAI) Oseltamivir and Zanamivir. However, amino acid (AA) substitutions in the neuraminidase may cause reduced inhibition or high antiviral resistance. In Mexico, the current state of knowledge about NAI susceptibility is scarce, in this study we report the results of 14 years of Influenza surveillance by phenotypic and genotypic methods. A total of 255 isolates were assessed with the NAI assay, including Influenza A(H1N1)pdm09, A(H3N2) and Influenza B (IBV). Furthermore, 827 sequences contained in the GISAID platform were analyzed in search of relevant mutations.Overall, five isolates showed highly reduced inhibition or reduced inhibition to Oseltamivir, and two showed reduced inhibition to Zanamivir in the NAI assays. Additionally, five A(H1N1)pdm09 sequences from the GISAID possessed AA substitutions associated to reduced inhibition to Oseltamivir and none to Zanamivir. Oseltamivir resistant A(H1N1)pdm09 harbored the H275Y mutation. No genetic mutations were identified in Influenza A(H3N2) and IBV. Overall, these results show that in Mexico the rate of NAI resistance is low (0.6%), but it is essential to continue the Influenza surveillance in order to understand the drug susceptibility of circulating strains. • Mexico reports data of 14 years on surveillance of influenza antiviral resistance. • Antiviral resistance of Influenza viruses circulating in Mexico remains low (0.6%). • Resistance to NAI was detected in A(H1N1)pdm09 viruses. [ABSTRACT FROM AUTHOR]

The clothes laundering process affords numerous opportunities for dissemination of infectious virus from contaminated clothing to appliance surfaces and other household surfaces and eventually to launderer's hands. We have explored the efficacy of laundry sanitizers for inactivating coronaviruses and influenza viruses. Virucidal efficacy was tested using standardized suspension inactivation methods (EN 14476) or hard-surface inactivation methods (ASTM E1053-20) against SARS-CoV-2, human coronavirus 229E (HCoV 229E), influenza A virus (2009-H1N1 A/Mexico), or influenza B virus (B/Hong Kong). Efficacy was measured in terms of log10 reduction in infectious virus titer, after 15 min contact time (suspension studies) or 5 min contact time (hard surface studies) at 20 ± 1 °C. In liquid suspension studies, laundry sanitizers containing p-chloro-m-xylenol (PCMX) or quaternary ammonium compounds (QAC) caused complete inactivation (≥ 4 log10) of HCoV 229E and SARS-CoV-2 within 15 min contact time at 20 ± 1 °C. In hard surface studies, complete inactivation (≥ 4 log10) of each coronavirus or influenza virus, including SARS-CoV-2, was observed following a 5-min contact time at 20 ± 1 °C. Respiratory viruses may remain infectious on clothing/fabrics and environmental surfaces for hours to days. The use of a laundry sanitizer containing microbicidal actives may afford mitigation of the risk of contamination of surfaces during handling of the laundry and washing appliances (i.e., washer/dryer or basin), adjacent surfaces, the waste water stream, and the hands of individuals handling clothes contaminated with SARS-CoV-2, influenza viruses, or other emerging enveloped viruses. [ABSTRACT FROM AUTHOR]

Influenza A virus (IAV) outbreaks constitute a constant threat to public health and pose a remarkable impact on socio‐economic systems worldwide. Interactions between wild and domestic birds, humans and swine can lead to spillover events. Backyard livestock systems in proximity to wetlands represent high‐risk areas for viral spread. However, some gaps remain in our knowledge of IAV transmission at the wildlife–livestock interface in Mexico. Hence, the study aimed at molecular identification and phylogenetic characterization of IAV in the wild duck–backyard livestock interface at a wetland of Mexico. A total of 875 animals were tested by real‐time RT‐PCR (qRT‐PCR). We detected IAV in 3.68% of the wild ducks sampled during the winter season 2016–2017. Nonetheless, the samples obtained from backyard poultry and swine tested negative. The highest IAV frequency (11.10%) was found in the Mexican duck (Anas diazi). Subtypes H1N1, H3N2 and H5N2 were detected. Phylogenetic analyses revealed that IAV detected in wild birds from the Lerma wetlands was mostly related to swine and poultry IAV strains previously isolated in the United States and Mexico. Except, the UIFMVZ377/H5N2 related to North American waterbirds. In conclusion, the co‐circulation of three IAV subtypes in wild ducks close to backyard farms in Mexico, as well as the local identification of influenza viruses genetically related to Mexican and North American IAV strains, highlights the importance of the Lerma marshes for influenza surveillance given the close interaction among wild birds, poultry, pigs and humans. [ABSTRACT FROM AUTHOR]

Introduction: Physical distancing preventive measures were implemented in Mexico as a response to the coronavirus disease 2019 (CoViD-19) pandemic. School closures occurred on March 16, 2020, in 10 out of 32 Mexican states, and one week later in the remaining states. Because the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the influenza virus have similar transmission mechanisms, we aimed to evaluate the impact of physical distancing on the incidence of influenza as a proxy of the impact on SARS-CoV-2 contagion. Methodology: A national flu surveillance system was cross-sectionally analyzed and daily average percent changes (APCs) of incidence rates were calculated throught Poisson regression models. Results: Greater decreasing trends (APCs -8.8, 95% CI: -12.5, -4.5; vs. -6.0, 95% CI: -9.9, -2.0; p = 0.026) were documented in the states with earlier school closures and across age groups, suggesting that earlier implementation of physical distance results in reduced SARS-CoV-2 spread. [ABSTRACT FROM AUTHOR]

Highly pathogenic H7N3 influenza A viruses have persisted in poultry in Mexico since 2012, diversifying into multiple lineages that have spread to three Mexican states, as of 2016. The H7N3 viruses segregate into three distinct clades that are geographically structured. All 2016 viruses are resistant to adamantane antiviral drugs and have an extended 24‐nucleotide insertion at the HA cleavage site that was acquired from host 28S ribosomal RNA. [ABSTRACT FROM AUTHOR]

Humans and swine are both affected by influenza viruses, and swine are considered a potential source of new influenza viruses. Transmission of influenza viruses across species is well documented. The aim of this study was to evaluate the seroprevalence of different influenza virus subtypes in veterinarians working for the Mexican swine industry, using a hemagglutination inhibition test. All sera tested were collected in July 2011. The data were analysed using a generalized linear model and a linear model to study the possible association of seroprevalence with the age of the veterinarian, vaccination status, and biosecurity level of the farm where they work. The observed seroprevalence was 12.3%, 76.5%, 46.9%, and 11.1% for the human subtypes of pandemic influenza virus (pH1N1), seasonal human influenza virus (hH1N1), the swine subtypes of classical swine influenza virus (swH1N1), and triple-reassortant swine influenza virus (swH3N2), respectively. Statistical analysis indicated that age was associated with hH1N1 seroprevalence ( P < 0.05). Similarly, age and vaccination were associated with pH1N1 seroprevalence ( P < 0.05). On the other hand, none of the studied factors were associated with swH1N1 and swH3N2 seroprevalence. All of the pH1N1-positive sera were from vaccinated veterinarians, whereas all of those not vaccinated tested negative for this subtype. Our findings suggest that, between the onset of the 2009 pandemic and July 2011, the Mexican veterinarians working in the swine industry did not have immunity to the pH1N1 virus; hence, they would have been at risk for infection with this virus if this subtype had been circulating in swine in Mexico prior to 2011. [ABSTRACT FROM AUTHOR]

Introduction: On April 2009, the Mexican Ministry of Health received notification of cases of severe pneumonia mostly affecting young healthy people; this was the beginning of the first influenza pandemic of the 21st century. The nature of the immune response to the influenza A(H1N1)2009 pandemic strain in Mexico at the beginning of the pandemic outbreak has not been completely defined. We describe the serological response to the 2009 pandemic influenza virus in paediatric patients with influenza-like illness, their household contacts (HHCs), and exposed health-care workers (HCWs) at the beginning of the pandemic outbreak in Mexico City. Methodology: thirty pre-epidemic and 129 epidemic samples were collected and serum antibodies were measured against A(H1N1)2009 pandemic virus and two non-pandemic swine influenza viruses by an haemagglutination inhibition assay . Results: 91% (29/32) of the convalescence samples from confirmed patients had an antibody titre ≥ 10 (GMT 25), 63% (41/65) of the HHCs (GMT 12), 41% of HCWs (GMT 6) and 13% (4/30) of pre-epidemic samples (GMT 6) for the pandemic influenza virus. Of the 32 confirmed cases, 60% had an antibody titre ≥ 40 for the pandemic strain, 53% for the A/swine/Iowa(H1N1) virus (GMT 62) and 43% for the A/swine/Texas(H3N2) virus (GMT 66). Conclusion: The antibody response to 2009 pandemic influenza virus was widespread in convalescence samples from patients with confirmed pandemic influenza infection but the GMT was below the protective titre. There was no evidence that antibodies to the swine influenza viruses had cross-protective effect against the 2009 pandemic influenza virus. [ABSTRACT FROM AUTHOR]

In this work, nineteen influenza A/H3N2 viruses isolated in Mexico between 2003 and 2012 were studied. Our findings show that different human A/H3N2 viral lineages co-circulate within a same season and can also persist locally in between different influenza seasons, increasing the chance for genetic reassortment events. A novel minor cluster was also identified, named here as Korea, that circulated worldwide during 2003. Frequently, phylogenetic characterization did not correlate with the determined antigenic identity, supporting the need for the use of molecular evolutionary tools additionally to antigenic data for the surveillance and characterization of viral diversity during each flu season. This work represents the first long-term molecular epidemiology study of influenza A/H3N2 viruses in Mexico based on the complete genomic sequences and contributes to the monitoring of evolutionary trends of A/H3N2 influenza viruses within North and Central America. [ABSTRACT FROM AUTHOR]

Introduction: The frequency and mortality of the pandemic caused by influenza A(H1N1)pdm09 might have been underestimated, especially in developing countries. This study was designed to quantify the possible underestimation of pandemic influenza mortality and evaluate the concordance between the data reported for A(H1N1)pdm09 mortality and the causes of death reported during the pandemic period of April 2009 to February 2010. Methodology: The death certificates of 754 confirmed cases of A(H1N1)pdm09 infection were included in the study. Data was analyzed using the United States Centers for Disease Control and Prevention's statistical model accounts for the variability in the proportion at each step using the Monte Carlo probabilistic model sampled from a uniform probability distribution. Results: A total of 1,969 deaths were estimated, with an estimated lethality of 5.53 per 100,000 (range, 3.5-8.76 per 100,000) in contrast with the 754 deaths and a lethality of 1.98 per 100,000 infected patients officially reported. In 631 of 754 (83.7%) death certificates from A(H1N1)pdm09 influenza-positive patients, influenza was not mentioned as a cause of death. Conclusions: It is possible that the mortality of the pandemic was three times higher than officially reported in Mexico. One source of error that could explain this underestimation is in the completion of death certificates, because in > 80% of confirmed cases of infection with influenza virus, it was not reported as the cause of death. [ABSTRACT FROM AUTHOR]

Background: The use of direct observation to monitor tuberculosis treatment is controversial: cost, practical difficulties, and lack of patient acceptability limit effectiveness. Telehealth is a promising alternative delivery method for improving implementation. This study aimed to evaluate the clinical and cost-effectiveness of a telehealth service delivering direct observation, compared to an in-person drive-around service. Methodology/Principal Findings: The study was conducted within a community nursing service in South Australia. Telehealth patients received daily video calls at home on a desktop videophone provided by the nursing call center. A retrospective cohort study assessed the effectiveness of the telehealth and traditional forms of observation, defined by the proportion of missed observations recorded in case notes. This data was inputted to a model, estimating the incremental cost-effectiveness ratio (ICER) of telehealth. Semi-structured interviews were conducted with current patients, community nursing and Chest Clinic staff, concerning service acceptability, usability and sustainability. The percentage of missed observations for the telehealth service was 12.1 (n = 58), compared to 31.1 for the in-person service (n = 70). Most of the difference of 18.9% (95% CI: 12.2 - 25.4) was due to fewer pre-arranged absences. The economic analysis calculated the ICER to be AUD$1.32 (95% CI: $0.51 - $2.26) per extra day of successful observation. The video service used less staff time, and became dominant if implemented on a larger scale and/or with decreased technology costs. Qualitative analysis found enabling factors of flexible timing, high patient acceptance, staff efficiency, and Chest Clinic support. Substantial technical problems were manageable, and improved liaison between the nursing service and Chest Clinic was an unexpected side-benefit. Conclusions/Significance: Home video observation is a patient-centered, resource efficient way of delivering direct observation for TB, and is cost-effective when compared with a drive-around service. Future research is recommended to determine applicability and effectiveness in other settings. [ABSTRACT FROM AUTHOR]

The 6th International Conference on Emerging Zoonoses, held at Cancun, Mexico, 24-27 February 2011, offered 84 participants from 18 countries, a snapshot of current research in numerous zoonoses caused by viruses, bacteria or prions. Co-chaired by Professors Heinz Feldmann and Jürgen Richt, the conference explored 10 topics: (i) The ecology of emerging zoonotic diseases; (ii) The role of wildlife in emerging zoonoses; (iii) Cross-species transmission of zoonotic pathogens; (iv) Emerging and neglected influenza viruses; (v) Haemorrhagic fever viruses; (vi) Emerging bacterial diseases; (vii) Outbreak responses to zoonotic diseases; (viii) Food-borne zoonotic diseases; (ix) Prion diseases; and (x) Modelling and prediction of emergence of zoonoses. Human medicine, veterinary medicine and environmental challenges are viewed as a unity, which must be considered under the umbrella of 'One Health'. Several presentations attempted to integrate the insights gained from field data with mathematical models in the search for effective control measures of specific zoonoses. The overriding objective of the research presentations was to create, improve and use the tools essential to address the risk of contagions in a globalized society. In seeking to fulfil this objective, a three-step approach has often been applied: (i) use cultured cells, model and natural animal hosts and human clinical models to study infection; (ii) combine traditional histopathological and biochemical approaches with functional genomics, proteomics and computational biology; and (iii) obtain signatures of virulence and insights into mechanisms of host defense response, immune evasion and pathogenesis. This meeting review summarizes 39 of the conference presentations and mentions briefly the 16 articles in this Special Supplement, most of which were presented at the conference in earlier versions. The full affiliations of all presenters and many colleagues have been included to facilitate further inquiries from readers. [ABSTRACT FROM AUTHOR]

Introduction: The Swine Origin A H1N1 Influenza Virus (SOIV) pandemic emerged in April 2009 affecting people and health-care systems worldwide. This study examined the differences among the early clinical features presented in confirmed SOIV cases, those who tested negative for SOIV infection, fatalities, and hospitalized cases. Methodology: We reviewed 1,024 initial medical records of patients presenting with acute respiratory symptoms who attended the respiratory emergency room of a general hospital in Mexico and had a confirmatory test for influenza AH1N1 by RT-PCR from April to December 2009. Results: Out of 1,024 cases, 457 (44%) were men with a mean age of 31±17 years; however, of these, SOIV confirmed cases were younger (26±8, p=0.000). SOIV infection was confirmed in 36% of the patients. Most (%?) cases presented mild infection, 20% of the patients required hospitalization, and 0.09% patients died. Asthma was more frequent in confirmed cases (p=0.028). Presence of COPD, systemic arterial hypertension, and diabetes mellitus was significant in confirmed hospitalized cases. Pulmonary rales, wheezing, and sudden symptom onset were more frequent and statistically significant in confirmed patients. Influenza-like illness was more frequent in confirmed cases (p=0.049). Conclusions: This study presents one of the largest series of the new SOIV infection confirmed by RT-PCR reported. This infection is frequently mild and affects mainly young adults. Sudden symptoms onset, pulmonary rales, and wheezing are early features of this infection. Asthma, COPD, systemic arterial hypertension, and diabetes mellitus should be identified to identify potentially severe and fatal cases. ILI helps distinguish SOIV infection. [ABSTRACT FROM AUTHOR]

Objective. Determine Vaccination Coverage (VC) among adults 60 years of age and older (EP), for influenza, pneumococcal and tetanus vaccines, association with socio-demographic characteristics and heterogeneity at state level. Material and Methods. Cross-sectional analysis based on information from 18 015 households visited in a national survey. General and vaccine information (self-report) for a randomly selected elder in each household is available. Results. The national VC level was found to be 56.5% (±0.97) for influenza, 44.3% (±0.98) for pneumococcus and 61.8% (±0.96) for tetanus. The VC was significantly lower for EP without health social services and higher for women. Almost 20.0% of EP recognized not having vaccines at all, due mainly that they didn't know it was a duty. Conclusions. Important improvements are shown in vaccination coverage among elderly in Mexico. Differentials suggest the need to intensify information campaigns and actions that could improve the accessibility to vaccines for this population. [ABSTRACT FROM AUTHOR]

Background: influenza viruses are significant human respiratory pathogens that cause an acute respiratory disease that can show up in a seasonal, epidemic or pandemic way. In April 2009, the first human cases of A H1N1 took place in Mexico City, which caused an epidemic that originated a sanitary alert. Objective: Identify the perception and attitudes of the workers of a health institution facing the epidemic in Mexico. Material and Methods: A survey was carried out amongst workers of the Instituto Nacional de Neurología y Neurocirugía of Mexico City, to evaluate their perception and attitudes about the measures adopted in the country and the institution. Results: The percentage of fear and concern among the workers of the institute were as high as 66%, more than 70% feared the infection of some relatives or friends; nevertheless, the participation and the execution of the preventive measures implemented by the sanitary authorities of Mexico and for the institute were mostly adopted. Conclusion: The workers are aware of the importance of continuing carrying out measures of prevention and hygiene mainly, nevertheless, it is necessary that the authorities of each institution verify and continue sensitizing their workers so that this protection element doesn't get lost and strengthen, to avoid the transmission and to be better prepared before a turnaround, or in the case of a new and potentially catastrophic event. [ABSTRACT FROM AUTHOR]

Summary: The influenza pandemic the world was waiting for may have arrived, but the early indications are that the first wave of human swine influenza A [H1N1], also referred to as H1N1 Mexico 09 or “swine flu”, is highly transmissible but of no greater virulence than seasonal influenza to date. The new swine flu H1N1 virus is a mixture of avian, porcine and human influenza RNA. With twenty thousand confirmed cases worldwide and 117 deaths within 7 weeks of the first acknowledgement of a possible pandemic by Mexican and WHO experts, the mortality rate is less than 0.1% and the majority of deaths centred upon the origin of the epidemic in Mexico [83%]. Swine flu is thus far a relatively mild illness seen predominantly in those who are healthy and under 25 years of age, perhaps reflecting protection from previous human influenza exposure in older people. As the virus spreads internationally, border protection issues have surfaced and public health initiatives are being progressively rolled out to minimise the transmission. Vaccines are being developed which will be trialled in the coming months with a likely availability by August 2009, in time for the northern hemisphere autumn and winter. Vigilance without alarm appears to be the recommendation so far. [Copyright &y& Elsevier]

A three-site pig herd infected with a H3N2 swine influenza virus (SIV) underwent a herd SIV elimination programme using herd closure and partial depopulation. The herd consisted of sow, nursery and finishing units, 1 to 2 km apart. Disease was noted in the sow unit and then the nursery unit. The herd temporarily stopped introduction of replacement animals, and replacement gilt introductions in the breeding herd was changed from monthly to quarterly. Gilts from a serologically negative source were also introduced and monitored. Virus elimination from growing pigs was attempted by totally depopulating the nursery and finishing sites once there was evidence that shedding in site 1 had stopped. Sentinel gilts remained serologically negative by haemagglutination inhibition (HI) test (0 of 69 animals negative) for at least 20 months after the initial disease. After restoring the pig flow in site 2, pigs did not experience flu-like clinical signs and HI serology results remained negative (0 of 30 animals tested) for the six months following repopulation of sites 2 and 3. In addition, nursery mortality was improved by 2·2 per cent, the growth rate was improved by 0·123 kg/day and feed efficiency was improved 0·26 points. Based on these results, SIV elimination was considered successful. [ABSTRACT FROM AUTHOR]

A new H1N1 triple-reassortant "swine" influenza virus was recently described in individuals from the United States and Mexico who presented with respiratory symptoms, and the same virus was subsequently confirmed in patients from several countries around the world. The circumstances surrounding the emergence of this pathogen, and the factors that facilitated the initial cross-species transmission, are still incompletely understood. It became apparent in the early days of the outbreak that the virus can be directly transmitted between humans. Pathogens that originate in animal reservoirs and subsequently acquire the potential for human-to-human transmission have caused outbreaks throughout human history. Although each outbreak is marked by its own particularities, it is important to remember the teachings that emerge from previous epidemics and pandemics. Integrating the important lessons of the past will provide the best opportunity to understand host-pathogen interaction and the most powerful approach to implementing effective prophylactic and therapeutic measures. [ABSTRACT FROM AUTHOR]

Background: In April 2009, novel swine-origin influenza viruses (S-OIV) were identified in patients from Mexico and the United States. The viruses were genetically characterized as a novel influenza A (H1N1) strain originating in swine, and within a very short time the S-OIV strain spread across the globe via human-to-human contact. Methodology: We conducted a comprehensive computational search of all available sequences of the surface proteins of H1N1 swine influenza isolates and found that a similar strain to S-OIV appeared in Thailand in 2000. The earlier isolates caused infections in pigs but only one sequenced human case, A/Thailand/271/2005 (H1N1). Significance: Differences between the Thai cases and S-OIV may help shed light on the ability of the current outbreak strain to spread rapidly among humans. [ABSTRACT FROM AUTHOR]

novel influenza A H1N1 virus of swine origin is responsible for the influenza epidemic affecting Mexico, the United States of America (USA), and 39 other countries. While the origin of this emerging pathogen remains uncertain, an increase in the reported incidence of respiratory diseases was noted during March 2009 at the town of La Gloria, in the southeastern state of Veracruz, Mexico. So far, this is the first community in which a case of novel influenza A H1N1 virus has been identified. Further cases were rapidly detected in other areas of Mexico and elsewhere. Initially, the atypical respiratory disease outbreak caused great uncertainty posing a challenge to the Mexican health system. Control measures such as social distancing, timely medical care, and personal hygiene have so far proven effective in containing the outbreak, resulting in a decline of the number of new cases. To the best of our knowledge, it appears that the virus might not be as virulent or contagious as previously thought. Here we provide a description of the influenza epidemic spread in Mexico. As the virus disseminates worldwide, there is concern about the possibility of a new reassortment resulting in a more pathogenic strain that will pose a threat for every country. The influenza epidemic provided lessons that underscore the importance of epidemiologic surveillance and preparedness. Further investigation to address questions about this new virus and conditions for its spread is warranted. [ABSTRACT FROM AUTHOR]

The article reports on the outbreak of respiratory illness in patients with influenza-like illness (ILI) which started in Veracruz and Oaxaca, Mexico in March, 2009. As stated, the General Directorate of Epidemiology (DGE) has released a national epidemiological alert for all units monitoring the illness. It is noted that the DGE surveillance identified 97 swine-origin influenza virus (S-OIV) patients on April 29, 2009. Also noted are preventive measures like informing airport passengers of the disease, distributing masks and hand sanitizers.

Influenza hemagglutinin (HA) is considered a major protective antigen of seasonal influenza vaccine but antigenic drift of HA necessitates annual immunizations using new circulating HA versions. Low variation found within conserved non-HA influenza virus (INFV) antigens may maintain protection with less frequent immunizations. Conserved antigens of influenza A virus (INFV A) that can generate cross protection against multiple INFV strains were evaluated in BALB/c mice using modified Vaccinia virus Ankara (MVA)-vectored vaccines that expressed INFV A antigens hemagglutinin (HA), matrix protein 1 (M1), nucleoprotein (NP), matrix protein 2 (M2), repeats of the external portion of M2 (M2e) or as tandem repeats (METR), and M2e with transmembrane region and cytoplasmic loop (M2eTML). Protection by combinations of non-HA antigens was equivalent to that of subtype-matched HA. Combinations of NP and forms of M2e generated serum antibody responses and protected mice against lethal INFV A challenge using PR8, pandemic H1N1 A/Mexico/4108/2009 (pH1N1) or H5N1 A/Vietnam/1203/2004 (H5N1) viruses, as demonstrated by reduced lung viral burden and protection against weight loss. The highest levels of protection were obtained with NP and M2e antigens delivered as MVA inserts, resulting in broadly protective immunity in mice and enhancement of previous natural immunity to INFV A. [ABSTRACT FROM AUTHOR]

Influenza, a zoonosis caused by various influenza A virus subtypes, affects a wide range of species, including humans. Pig cells express both sialyl-α-2,3-Gal and sialyl-α-2,6-Gal receptors, which make them susceptible to infection by avian and human viruses, respectively. To date, it is not known whether wild pigs in Mexico are affected by influenza virus subtypes, nor whether this would make them a potential risk of influenza transmission to humans. In this work, 61 hogs from two municipalities in Campeche, Mexico, were sampled. Hemagglutination inhibition assays were performed in 61 serum samples, and positive results were found for human H1N1 (11.47%), swine H1N1 (8.19%), and avian H5N2 (1.63%) virus variants. qRT-PCR assays were performed on the nasal swab, tracheal, and lung samples, and 19.67% of all hogs were positive to these assays. An avian H5N2 virus, first reported in 1994, was identified by sequencing. Our results demonstrate that wild pigs are participating in the exposure, transmission, maintenance, and possible diversification of influenza viruses in fragmented habitats, highlighting the synanthropic behavior of this species, which has been poorly studied in Mexico. [ABSTRACT FROM AUTHOR]

Antibodies against influenza viruses were detected in 115 serum samples from indigenous Mayan persons from Kochol, Yucatan. Seropositivity rates were 26,9% to A/Bayern/7/95, 40,8% to A/Sydney/5/97, 1,7% to A/Swine/ Wisconsin/238/97, and 79,1% to A/Swine/Minnesota/ 593/99, This report is the first in Mexico of the prevalence of antibodies to swine influenza virus in humans. [ABSTRACT FROM AUTHOR]

The author focuses on the H1N1 virus, also known as swine influenza, in Africa. The author recalls his response to a phone call he received from a journalist requesting information on the government of Malawi's preparation to deal with swine flu. The author states that the swine flu virus has genetic material that allow it to cross species. He notes that there are no African countries with cases of swine flu and discusses how the epidemic spread from Mexico, where it originated.

The article focuses on the H1N1 influenza strain. It states that the U.S. Centers for Disease Control and Prevention initially reported an unusual swine flu outbreak on April 21, 2009 in a dispatch to "Morbidity and Mortality Weekly Report." Former Secretary of Health of Mexico, Julio Frenk, said that in the wake of avian influenza outbreaks, there has been an effort to prepare for influenza outbreaks. It mentions that reports of the H1N1 influenza virus in Mexico, where the disease is believed to have first appeared, was slow because it overlapped with the end of the Mexican flu season. It states that the World Health Organization suggested that vaccine manufacturers should prepare H1N1 vaccines for the 2009-2010 flu season.

Background: In the present study, we analyzed the presence of antibodies to four different influenza viruses (pH1N1, hH1N1, swH1N1, and swH3N2) in the sera of 2094 backyard pigs from Mexico City. The sera were obtained between 2000 and 2009., Objectives: The aim of this study was to perform a retrospective analysis of the 2000-2009 period to determine the seroprevalence of antibodies against pH1N1, hH1N1, swH1N1, and swH3N2 viruses in sera obtained from backyard pigs in Mexico City., Methods: Antibody detection was conducted with hemagglutination inhibition assay (HI) using four influenza viruses. We used linear regression to analyze the tendency of antibody serum titers throughout the aforementioned span., Results: We observed that the antibody titers for the pH1N1, swH1N1, and swH3N2 viruses tended to diminish over the study period, whereas the antibodies to hH1N1 remained at low prevalence for the duration of the years analyzed in this study. A non-significant correlation (P > 0.05) between antibody titers for pH1N1 and swH1N1 viruses was observed (0.04). It contrasts with the significance of the correlation (0.43) observed between the swH1N1 and swH3N2 viruses (P < 0.01)., Conclusions: Our findings showed no cross-antigenicity in the antibody response against the same subtype. Antibodies against pH1N1 virus were observed throughout the 10-year study span, implying that annual strains shared some common features with the pH1N1 virus since 2000, which would then be capable of supporting the ongoing presence of these antibodies., (© John Wiley & Sons Ltd.)