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Background Equine influenza virus (EIV) is considered enzootic in North America and experimental studies have documented human EIV infections. Study design This cross-sectional study examined 94 horse-exposed and 34 non-exposed controls for serological evidence of EIV infection. Sera were evaluated for antibodies against three EIV and two human H3N2 viruses using microneutralization (MN), neuraminidase inhibition (NI), enzyme-linked lectin (ELLA), and hemagglutination inhibition (HI) serological assays. Risk factor analyses were conducted using logistic regression and proportional odds modeling. Results There was evidence of previous infection by MN assay against A/equine/Ohio/2003(H3N8) but not the other 2 EIVs. Eleven (11.7%, maximum titer 1:320) horse-exposed and 2 (5.9%, maximum titer 1:160) control subjects had MN titers ≥1:80. Among the horse-exposed, 18 (19.1%) were positive by NI assay and 8 (8.5%) had elevated ELLA titers ≥1:10. Logistic regression modeling among horse-exposed revealed that having an elevated MN or ELLA titer (≤1:10) was associated with having a positive NI titer (OR = 4.9; 95% CI = 1.3–18.7, and OR = 53.2; 95% CI = 5.9–478.5, respectively). Upon proportional odds modeling, having worked as an equine veterinarian (OR = 14.0; 95% CI = 2.6–75.9), having a history of smoking (OR = 3.1; 95% CI = 1.2–7.7), and receipt of seasonal influenza vaccine between 2000 and 2005 (OR = 2.3; 95% CI = 1.1–5.0) were important independent risk factors for elevations in MN assay. Conclusions While we cannot rule out confounding exposures, these data support the premise that occupational exposure to EIV may lead to human infection.

In developing countries, public health professionals and scientists need targeted training and practical skills to respond to global emerging infectious disease threats. The Certificate in Emerging Infectious Disease Research was developed in 2008 to aid such professionals to respond to complex emerging disease problems. The short-course was modified slightly in 2013 and renamed the Certificate in One Health. To evaluate the immediate impact of the short-course, an online survey of 176 past participants from both the courses was conducted. The survey tool assessed the program’s process, impact, and outcome measures respectively via assessing the courses’ perceived strengths and weaknesses, perceived skills gained, and the participants’ current position, publication status, funding status, and educational attainment; 85 (48.3%) participants completed the survey. Reported program strengths included the curriculum, expertise of lecturers, and diversity of the training cohort. The principal reported weakness was the compressed academic schedule. The most frequently reported benefits included: epidemiological and biostatistical skills, followed by One-Health knowledge, and research skills. Twenty-eight percent of the survey respondents reported publishing one or more manuscripts since completing the course and 21% reported receiving research funding. The course appears to have had a positive, immediate impact on the students’ self-perceived knowledge and capabilities.

The first known infection by influenza A(H9N2) occurred in 1966 among turkeys in Wisconsin. Since the 1990s, the virus has readily circulated among domestic poultry populations in several Asian countries and is now considered to have a near global, albeit sporadic distribution among poultry. Influenza A(H9N2) has also been identified in wild birds, domestic mammals, and, occasionally, in humans [1, 2]. Zoonotic transmission of influenza A(H9N2) was not considered a concern until 1998–1999, when the virus was first isolated from pig samples [2]; seropositive human cases were detected in Guangdong Province, China [3]; and the virus was isolated from hospitalized patients in Hong Kong [1]. Although human influenza A(H9N2) cases have only been reported in Hong Kong and mainland China, and more recently in Bangladesh [1, 4, 5], serological evidence of human infection has been reported in Asia, the Middle East, Africa, and parts of North America (Figure ​(Figure11). Figure 1. Reported global distribution for influenza A(H9N2) in humans and animals from 1997 to 2013. Countries that detected influenza A(H9N2) in poultry have an orange background. Species-specific symbols were assigned to each country. When a human or animal ... Human infection with influenza A(H9N2) generally results in mild or asymptomatic illness and often goes unnoticed [6]. However, influenza A(H9N2) is a potential pandemic threat because of its rapid evolution, ability to acquire and transfer genetic materials from other pathogenic subtypes, and efficiency in poultry-to-human transmission [7, 8]. Currently, influenza A(H9N2) infections in poultry have led to multiple reassortments, resulting in many novel genotypes of influenza A(H9N2) with gene segments from various lineages and serving as a constant reminder of its ability to acquire and transfer pandemic potential among the circulating influenza strains [9, 10]. Molecular analyses of the recently emerged influenza A(H7N9) and influenza A(H10N8) suggest that they have acquired gene segments from influenza A(H9N2) [11, 12], which probably enabled them to survive and be repeatedly transmitted among poultry before adapting to humans. Unlike other avian influenza viruses (eg, influenza A[H5N1]) that chiefly bind to human receptors in the lower respiratory tract, influenza A(H9N2) binds to α-2,6 sialic acid receptors that are abundant in the human upper respiratory tract [13], allowing for much greater infection efficiency. Given the pandemic potential of influenza A(H9N2), it is important to know the burden of human infections. However, the variation attributed to serological assays makes it difficult to accurately estimate the overall burden of influenza A(H9N2) infections. Hence, for this systematic review we sought to evaluate the overall burden of influenza A(H9N2) infection among avian-exposed human populations by summarizing serological data identified in the published literature. In addition, we compared the disease burden revealed by the 2 assays with that yielded by a standardized case definition for serological evidence of influenza A(H9N2) infection.

Journal of Infection - In Press.Proof corrected by the author Available online since dimanche 21 aout 2016

Pork production in China is rapidly increasing and swine production operations are expanding in size and number. However, the biosecurity measures necessary to prevent swine disease transmission, particularly influenza A viruses (IAV) that can be zoonotic, are often inadequate. Despite this risk, few studies have attempted to comprehensively study IAV ecology in swine production settings. Here, we present environmental and animal sampling data collected in the first year of an ongoing five-year prospective epidemiological study to assess IAV ecology as it relates to swine workers, their pigs, and the farm environment. From March 2015 to February 2016, we collected 396 each of environmental swab, water, bioaerosol, and fecal/slurry samples, as well as 3300 pig oral secretion samples from six farms in China. The specimens were tested with molecular assays for IAV. Of these, 46 (11.6%) environmental swab, 235 (7.1%) pig oral secretion, 23 (5.8%) water, 20 (5.1%) bioaerosol, and 19 (4.8%) fecal/slurry specimens were positive for influenza A by qRT-PCR. Risk factors for IAV detection among collected samples were identified using bivariate logistic regression. Overall, these first year data suggest that IAV is quite ubiquitous in the swine production environment and demonstrate an association between the different types of environmental sampling used. Given the mounting evidence that some of these viruses freely move between pigs and swine workers, and that mixing of these viruses can yield progeny viruses with pandemic potential, it seems imperative that routine surveillance for novel IAVs be conducted in commercial swine farms.

Horses are critically important for Mongolian herders’ livelihoods, providing transportation and food products, and playing important cultural roles. Equine influenza virus (EIV) epizootics have been frequent among Mongolia’s horses, with five occurring since 1970. We sought to estimate the prevalence for EIV infection among horses and Bactrian camels with influenza-like illness between national epizootics. In 2016–2017, active surveillance for EIV was periodically performed in four aimags (provinces). Nasal swabs were collected from 680 horses and 131 camels. Seven of the horse swabs were “positive” for qRT-PCR evidence of influenza A (Ct value ≤ 38). Two more were “suspect positive” (Ct value > 38 and ≤ 40). These nine specimens were collected from four aimags. None of the camel specimens had molecular evidence of infection. Despite serial blind passage in Madin-Darby Canine Kidney cells (MDCK) cells, none of the nine horse specimens yielded an influenza A virus. None of the 131 herder households surveyed had recently vaccinated their horses against EIV. It seems likely that sporadic EIV is enzootic in multiple Mongolian aimags. This finding, the infrequent use of EIV vaccination, periodic prevalence of highly pathogenic avian influenza, and the mixing of domestic and wild equid herds suggest that Mongolia may be a hot spot for novel EIV emergence.

In 2015–2017, we helped rural Mongolian clinicians with poor infrastructure adopt rapid influenza diagnostic tests (RIDTs). In their hands, the Quidel Sofia Influenza A Test was both sensitive (75%) and specific (100%). If made widely available, such RIDTs would have the potential to markedly reduce influenza morbidity and mortality in Mongolia.

There have been many terms used to describe the One Health concept, including movement, strategy, framework, agenda, approach, among others. However, the inter-relationships of the disciplines engaged in the One Health concept have not been well described. To identify and better elucidate the internal feedback mechanisms of One Health, we employed a system dynamics approach. First, a systematic literature review was conducted via searches in PubMed, Web of Knowledge, and ProQuest with the search terms: 'One Health' and (concept* or approach*). In addition, we used the HistCite® tool to add significant articles on One Health to the library. Then, of the 2368 articles identified, 19 were selected for evaluating the inter-relationships of disciplines engaged in One Health. Herein, we report a visually rich, theoretical model regarding interactions of various disciplines and complex problem descriptors engaged in One Health problem solving. This report provides a conceptual framework for future descriptions of the interdisciplinary engagements involved in One Health.

Summary During the last 10 years, scientists have grown increasingly aware that emerging respiratory viruses are often zoonotic in their origin. These infections can originate from or be amplified in livestock. Less commonly recognized are instances when humans have transmitted their respiratory pathogens to animals (reverse zoonoses). Even with this knowledge of viral exchange at the human–livestock interface, few studies have been conducted to understand this cross‐over. In this pilot study, we examined persons with influenza‐like illness at an outpatient clinic for evidence of infection with novel zoonotic respiratory pathogens in rural North Carolina where there are dense swine and poultry farming. Environmental air sampling was also conducted. From July 2016 to March 2017, a total of 14 human subjects were enrolled and sampled, and 192 bioaerosol samples were collected. Of the 14 human subject samples molecularly tested, three (21.4%) were positive for influenza A, one (7.1%) for influenza B and one (7.1%) for human enterovirus. Of the 192 bioaerosol samples collected and tested by real‐time RT‐PCR or PCR, three (1.6%) were positive for influenza A and two (1.0%) for adenovirus. No evidence was found for novel zoonotic respiratory viruses.

Background Our understanding of influenza A virus transmission between humans and pigs is limited. Methods Beginning in 2015, we used a One Health approach and serial sampling to prospectively study 299 swine workers and 100 controls, their 9000 pigs, and 6 pig farm environments in China for influenza A viruses (IAVs) using molecular, culture, and immunological techniques. Study participants were closely monitored for influenza-like illness (ILI) events. Results Upon enrollment, swine workers had higher serum neutralizing antibody titers against swine H1N1 and higher nasal wash total immunoglobulin A (IgA) and specific IgA titers against swine H1N1 and H3N2 viruses. Over a period of 12 months, IAVs were detected by quantitative reverse-transcription polymerase chain reaction in 46 of 396 (11.6%) environmental swabs, 235 of 3300 (7.1%) pig oral secretion, 23 of 396 (5.8%) water, 20 of 396 (5.1%) aerosol, and 19 of 396 (4.8%) fecal-slurry specimens. Five of 32 (15.6%) participants with ILI events had nasopharyngeal swab specimens that were positive for IAV, and 17 (53.1%) demonstrated 4-fold rises in neutralization titers against a swine virus. Reassorted Eurasian avian-lineage H1N1, A(H1N1)pdm09-like, and swine-lineage H3N2 viruses were identified in pig farms. The A(H1N1)pdm09-like H1N1 viruses identified in swine were nearly genetically identical to the human H1N1 viruses isolated from the participants with ILI. Conclusions There was considerable evidence of A(H1N1)pdm09-like, swine-lineage H1N1, and swine-lineage H3N2 viruses circulating, likely reassorting, and likely crossing species within the pig farms. These data suggest that stronger surveillance for novel influenza virus emergence within swine farms is imperative.

With multiple available vaccines and antivirals, seasonal influenza A is typically a self-limited acutely debilitating illness in young healthy adults. Here, we illustrate unexpected morbidity and mortality in a relatively young and healthy patient seen at a large tertiary care academic medical center for seasonal influenza A (H3N2) complicated by community-acquired pneumonia, hypoxic respiratory failure, septic shock, and death.

Small-scale farming may have large impacts on the selection and spread of antimicrobial resistance to humans. We conducted an observational study to evaluate antibiotic-resistant

Anaplasma and Ehrlichia are tick-borne bacterial pathogens that cause human granulocytic anaplasmosis, human monocytic ehrlichiosis, and are severe threats to livestock economies like Mongolia. In this study, ticks were collected, identified, and pooled (n = 299) from three distinct environments across central Mongolia. Each pool was initially tested for Anaplasma/Ehrlichia using a 16S rRNA PCR assay that detects both genera, and specific PCR testing was done to identify those positive samples. Maximum likelihood estimation (MLE) of infection rates of ticks collected from the environment in Selenge aimag (province) found infection rates of Ixodes persulcatus ticks to be 2.0% (95% CI: 0.7, 4.3%) for A. phagocytophilum and 0.8% (95% CI: 0.1, 2.5%) for both nonspecific Ehrlichia and Anaplasma. Ehrlichia muris was only detected in I. persulcatus ticks collected from the Selenge aimag, where the MLE was 1.2% (95% CI: 0.1, 2.5%). The calculated MLE infection rate of Anaplasma spp. in questing Dermacentor nuttalli ticks ranged from 1.9% (95% CI: 1.1, 9.1%) in the Tov aimag to 2.3% (95% CI: 1.3, 10.8%) in the Selenge aimag. However, when examining MLE in ticks removed from livestock, estimates increase substantially, ranging from 7.8% (95% CI: 4.2, 13.3%) in Dornogovi to 22.5% (95% CI: 14.3, 34.3%) in Selenge, suggesting that livestock play a key role in disease maintenance. Considering the collective economic losses that can result from these pathogens and the potential for illness in nomadic herdsmen, these results highlight the need for enhanced TBD surveillance and prevention measures within Mongolia.

Background Respiratory tract infections (RTIs) are common during the Hajj season and are caused by a variety of organisms, which can be transmitted via the air or contaminated surfaces. We conducted a study aimed at sampling the environment in the King Abdul Aziz International (KAAI) Airport, Pilgrims City, Jeddah, during Hajj season to detect respiratory pathogens. Methods Active air sampling was conducted using air biosamplers, and swabs were used to sample frequently touched surfaces. A respiratory multiplex array was used to detect bacterial and viral respiratory pathogens. Results Of the 58 environmental samples, 8 were positive for at least 1 pathogen. One air sample (1 of 18 samples, 5.5%) tested positive for influenza B virus. Of the 40 surface samples, 7 (17.5%) were positive for pathogens. These were human adenovirus (3 out of 7, 42.8%), human coronavirus OC43/HKU1 (3 out of 7, 42.8%), Haemophilus influenzae (1 out of 7, 14.2%), and Moraxella catarrhalis (1 out of 7, 14.2%). Chair handles were the most commonly contaminated surfaces. The handles of 1 chair were cocontaminated with coronavirus OC43/HKU1 and H influenzae. Conclusion Respiratory pathogens were detected in the air and on surfaces in the KAAI Airport in Pilgrims City. Larger-scale studies based on our study are warranted to determine the role of the environment in transmission of respiratory pathogens during mass gathering events (eg, Hajj) such that public health preventative measures might be better targeted.

Middle East respiratory syndrome coronavirus (MERS-CoV) is an emerging viral pathogen that primarily causes respiratory illness. We conducted a seroprevalence study of banked human serum samples collected in 2012 from Southern Saudi Arabia. Sera from 300 animal workers (17% with daily camel exposure) and 50 non-animal-exposed controls were examined for serological evidence of MERS-CoV infection by a pseudoparticle MERS-CoV spike protein neutralization assay. None of the sera reproducibly neutralized the MERS-CoV-pseudotyped lentiviral vector. These data suggest that serological evidence of zoonotic transmission of MERS-CoV was not common among animal workers in Southern Saudi Arabia during July 2012.

Summary Respiratory tract infections rank second as causes of adult and paediatric morbidity and mortality worldwide. Respiratory tract infections are caused by many different bacteria (including mycobacteria) and viruses, and rapid detection of pathogens in individual cases is crucial in achieving the best clinical management, public health surveillance, and control outcomes. Further challenges in improving management outcomes for respiratory tract infections exist: rapid identification of drug resistant pathogens; more widespread surveillance of infections, locally and internationally; and global responses to infections with pandemic potential. Developments in genome amplification have led to the discovery of several new respiratory pathogens, and sensitive PCR methods for the diagnostic work-up of these are available. Advances in technology have allowed for development of single and multiplexed PCR techniques that provide rapid detection of respiratory viruses in clinical specimens. Microarray-based multiplexing and nucleic-acid-based deep-sequencing methods allow simultaneous detection of pathogen nucleic acid and multiple antibiotic resistance, providing further hope in revolutionising rapid point of care respiratory tract infection diagnostics.

Summary Several new viral respiratory tract infectious diseases with epidemic potential that threaten global health security have emerged in the past 15 years. In 2003, WHO issued a worldwide alert for an unknown emerging illness, later named severe acute respiratory syndrome (SARS). The disease caused by a novel coronavirus (SARS-CoV) rapidly spread worldwide, causing more than 8000 cases and 800 deaths in more than 30 countries with a substantial economic impact. Since then, we have witnessed the emergence of several other viral respiratory pathogens including influenza viruses (avian influenza H5N1, H7N9, and H10N8; variant influenza A H3N2 virus), human adenovirus-14, and Middle East respiratory syndrome coronavirus (MERS-CoV). In response, various surveillance systems have been developed to monitor the emergence of respiratory-tract infections. These include systems based on identification of syndromes, web-based systems, systems that gather health data from health facilities (such as emergency departments and family doctors), and systems that rely on self-reporting by patients. More effective national, regional, and international surveillance systems are required to enable rapid identification of emerging respiratory epidemics, diseases with epidemic potential, their specific microbial cause, origin, mode of acquisition, and transmission dynamics.

Summary The past decade has seen the emergence of several novel viruses that cause respiratory tract infections in human beings, including Middle East respiratory syndrome coronavirus (MERS-CoV) in Saudi Arabia, an H7N9 influenza A virus in eastern China, a swine-like influenza H3N2 variant virus in the USA, and a human adenovirus 14p1 also in the USA. MERS-CoV and H7N9 viruses are still a major worldwide public health concern. The pathogenesis and mode of transmission of MERS-CoV and H7N9 influenza A virus are poorly understood, making it more difficult to implement intervention and preventive measures. A united and coordinated global response is needed to tackle emerging viruses that can cause fatal respiratory tract infections and to fill major gaps in the understanding of the epidemiology and transmission dynamics of these viruses.

In recent years Nigeria has experienced sporadic incursions of highly pathogenic H5N1 avian influenza among poultry. In 2008, 316 poultry-exposed agricultural workers, and 54 age-group matched non-poultry exposed adults living in the Enugu or Ebonyi States of Nigeria were enrolled and then contacted monthly for 24 months to identify acute influenza-like-illnesses. Annual follow-up sera and questionnaire data were collected at 12 and 24 months. Participants reporting influenza-like illness completed additional questionnaires, and provided nasal and pharyngeal swabs and acute and convalescent sera. Swab and sera specimens were studied for evidence of influenza A virus infection. Sera were examined for elevated antibodies against 12 avian influenza viruses by microneutralization and 3 human viruses by hemagglutination inhibition. Four (3.2%) of the 124 acute influenza-like-illness investigations yielded molecular evidence of influenza, but virus could not be cultured. Serial serum samples from five poultry-exposed subjects had a ≥4-fold change in microneutralization titers against A/CK/Nigeria/07/1132123(H5N1), with three of those having titers ≥1:80 (maximum 1:1,280). Three of the five subjects (60%) reported a preceding influenza-like illness. Hemagglutination inhibition titers were ≥4-fold increases against one of the human viruses in 260 participants. While cross-reactivity from antibodies against other influenza viruses cannot be ruled out as a partial confounder, over the course of the 2-year follow-up, at least 3 of 316 (0.9%) poultry-exposed subjects had evidence for subclinical HPAI H5N1 infections. If these data represent true infections, it seems imperative to increase monitoring for avian influenza among Nigeria's poultry and poultry workers.

Background Equine influenza virus (EIV) is considered enzootic in Europe (except Iceland), Asia, North Africa, and North and South America. When EIV outbreaks occur they may severely impact the equine and tourist industries. Australia faced its first EIV outbreak beginning in August of 2007. The outbreak was concentrated in New South Wales and Queensland, with more than 1400 confirmed EIV infections in horses during the first month. Rapid response from the equine industry and the federal government was successful and Australia was declared free from EIV by the end of 2007. Objectives This cross-sectional study was designed to examine associations between exposure to EIV-infected horses and evidence of EIV infection in humans. Study design Employing informed consent, between October 2007 and April 2008, 100 subjects (89 with horse exposures and 11 non-exposed) were enrolled during equine events and at the University of the Sunshine Coast. All subjects provided a blood sample and were asked to complete an online questionnaire including health history, animal exposure and demographic information. Sera samples were tested for the presence of antibodies against two H3N8 EIV strains using microneutralization, hemagglutination inhibition, and enzyme-linked lectin assays. Results Evidence for H3N8 infection was sparse, with only 9 study participants having any indication of H3N8 infection and the seroreactivity seen was low and easily explained by cross-reactions against human influenza strains or vaccines. Conclusions These data provide little evidence to support the premise that EIV infections occurred among humans exposed to EIV-infected horses during the 2007 Australian epizootic.

Background Human adenovirus 55 (HAdV-55) has caused recent outbreaks of acute respiratory disease (ARD) among adults and military trainees. The active surveillance for HAdV infections was sparse in China, and current knowledge on the HAdV-type distributions and its molecular evolution is lacking. Objectives To acquire better understanding on the prevalence and molecular evolution of HAdV-55 strains in China, for an informed strategy for disease control and prevention. Population/Methods Nasopharyngeal aspirates were collected from hospitalized children with ARTI in Chongqing during 2009–2012. The genotype of HAdV isolates were determined by sequencing the partial hexon and fiber genes. Whole genome sequences of HAdV-55 were obtained for molecular evolution analysis. Results About 191 (8·55%) HAdV were detected in 2234 children, including 92 (48·2%) with HAdV-7, 72 (37·7%) with HAdV-3, 6 (3·1%) with HAdV-55, 5 (2·6%) with HAdV-5, 4 (2·1%) with HAdV-1, 1 (0·5%) with HAdV-2, and 11(5·8%) with untyped HAdV. Four of these children developed pneumonia, two of whom were diagnosed with severe pneumonia and/or encephalopathy. HAdV-55 isolates clustered with HAdV-11 sequences based on the hexon gene and clustered with HAdV-14 sequences based on the fiber gene and the whole genome. The overall evolutionary rates of hexon gene, fiber gene, and whole genome of HAdV-55 were estimated at 6·2 × 10−5 s/s/y, 8·0 × 10−5 s/s/y, and 1·7 × 10−5 s/s/y, respectively. Conclusions This study suggested HAdV-55 as an emerging infectious disease pathogen has conserved genetic structure and is closely related to each other. Further molecular investigation based on HAdV-55 of wider origin might facilitate understanding its diversity, dissemination, and transmission in China.

Infectious disease prevention and control has been among the top public health objectives during the last century. However, controlling disease due to pathogens that move between animals and humans has been challenging. Such zoonotic pathogens have been responsible for the majority of new human disease threats and a number of recent international epidemics. Currently, our surveillance systems often lack the ability to monitor the human-animal interface for emergent pathogens. Identifying and ultimately addressing emergent cross-species infections will require a "One Health" approach in which resources from public veterinary, environmental, and human health function as part of an integrative system. Here we review the epidemiology of bovine zoonoses from a public health perspective.

Interspecies transmission of equine influenza A(H3N8) virus has resulted in establishment of a canine influenza virus. To determine if something similar could happen with cats, we experimentally infected 14 cats with the equine influenza A(H3N8) virus. All showed clinical signs, shed virus, and transmitted the virus to a contact cohort.

Objectives The zoonotic potential of H3N8 canine influenza virus (CIV) has not been previously examined; yet considering the popularity of dogs as a companion animal and the zoonotic capabilities of other influenza viruses, the public health implications are great. This study aimed to determine the seroprevalence of antibodies against CIV among a US cohort. Design A cross-sectional seroepidemiological study was conducted between 2007 and 2010. Setting Recruitments primarily occurred in Iowa and Florida. Participants were enrolled at dog shows, or at their home or place of employment. Sample Three hundred and four adults occupationally exposed to dogs and 101 non-canine-exposed participants completed a questionnaire and provided a blood sample. Main outcome measures Microneutralization and neuraminidase inhibition assays were performed to detect human sera antibodies against A/Canine/Iowa/13628/2005(H3N8). An enzyme-linked lectin assay (ELLA) was adapted to detect antibodies against a recombinant N8 neuraminidase protein from A/Equine/Pennsylvania/1/2007(H3N8). Results For all assays, no significant difference in detectable antibodies was observed when comparing the canine-exposed subjects to the non-canine-exposed subjects. Conclusion While these results do not provide evidence for cross-species CIV transmission, influenza is predictably unpredictable. People frequently exposed to ill dogs should continually be monitored for novel zoonotic CIV infections.

In recent years, Mongolia has experienced recurrent epizootics of equine influenza virus (EIV) among its 2·1 million horses and multiple incursions of highly pathogenic avian influenza (HPAI) virus via migrating birds. No human EIV or HPAI infections have been reported. In 2009, 439 adults in Mongolia were enrolled in a population-based study of zoonotic influenza transmission. Enrollment sera were examined for serological evidence of infection with nine avian, three human, and one equine influenza virus strains. Seroreactivity was sparse among participants suggesting little human risk of zoonotic influenza infection.

Background Human trichomoniasis is the most common non-viral sexually transmitted disease, yet immune responses are not well studied. Methods Since the Trichomonas vaginalis lipophosphoglycan (TvLPG) is an important virulence factor, a bank of eight monoclonal antibodies was generated to define the antigen in clinical isolates. The TvLPG-specific antibody response of women who were culture positive (n=33) or negative (n=33) for T vaginalis infection was determined by isotype-specific ELISA. Results The bank of monoclonal antibodies reacted with conserved surface TvLPG epitopes in 27 isolates from pregnant women at their first prenatal visit. Conserved TvLPG epitopes were shown to be surface exposed by immunofluorescence. Sera collected from the same patients at the same time were assayed for specific antibodies. Serum and vaginal secretions from 33 T vaginalis-positive women had statistically higher IgG anti-TvLPG levels than age-matched and race-matched negative controls in the same clinical study (p

Objectives Human adenovirus (HAdV) type 14 had been infrequently associated with outbreaks of febrile respiratory illness (FRI) until the HAdV-14p1 emerged in 2006 and rapidly spread in the United States. Here, we report an outbreak of FRI caused by HadV-14p1 that occurred in 2011 at a primary and middle school in China. Design The basic information of the outbreak was recored; throat swabs were collected from 17 patients, polymerase chain reaction, A549 cell culture, and sequencing were used to identify the pathogen of the outbreak.. Results Total of 43 students were infected in this outbreak. Boys were more than girls. We identified 11 HAdV-positive specimens and 6 HAdV isolates. Genetic analysis showed that the complete hexon, fiber, and E1A sequences of isolates were nearly 100% identical with other HAdV-14p1 sequences deposited in GenBank. Conclusions HadV-14p1 has caused outbreaks of pneumonia and mortality among adults in the United States and Europe. It may cause similar conditions among Chinese adults due to poor hygiene and sanitation. It seems prudent for China to develop a national surveillance system to determine the etiology of severe respiratory diseases and deaths among adults and school-aged children.

Background The clinical impact of polymicrobial respiratory infections remains uncertain. Previous reports are contradictory regarding an association with severe disease. Methods Three hundred forty-six specimens from children with acute respiratory illness identified at the University of Iowa Hospitals and Clinics Clinical Microbiology Laboratory were evaluated by direct immunofluorescent assay and/or viral culture by Clinical Microbiology Laboratory and later by molecular study for the presence of influenza, parainfluenza, respiratory syncytial virus, adenovirus, human metapneumovirus, rhinovirus and human bocavirus. Demographic and clinical data were abstracted from medical records. Results Multiple viruses were detected in 46 (21.7%) of 212 virus-positive specimens with the most frequent virus-virus combinations being HRV-respiratory syncytial virus (n = 12), HRV-human bocavirus (n = 6) and HRV-parainfluenza virus 3 (n = 4). Risk factors for coinfection included male gender (OR [odds ratio]: 1.70, 95% confidence interval [CI]: 0.83-3.46), 6 months to 1 year age (OR: 2.15, 95% CI: 0.75-6.19) and history of immunosuppression (OR: 2.05, 95% CI: 0.99-4.23). Children with viral coinfections were less likely than children with single virus infections to be admitted to an intensive care unit (OR: 0.32, 95% CI: 0.08-1.27); however, this may be explained by undetected viral-bacterial coinfections. Conclusions HRV, respiratory syncytial virus, human bocavirus, and polymicrobial infections were prevalent in this study. Although the cross-sectional design could not easily examine polymicrobial infection and disease severity, prospective, population-based research regarding the clinical impact of such infections is warranted.

Summary: Background: Southeast Asia remains a critical region for the emergence of novel and/or zoonotic influenza, underscoring the importance of extensive sampling in rural areas where early transmission is most likely to occur. Methods: In 2008, 800 adult participants from eight sites were enrolled in a prospective population-based study of avian influenza (AI) virus transmission where highly pathogenic avian influenza (HPAI) H5N1 virus had been reported in humans and poultry from 2006 to 2008. From their enrollment sera and questionnaires, we report risk factor findings for serologic evidence of previous infection with 18 AI virus strains. Results: Serologic assays revealed no evidence of previous infection with 13 different low-pathogenic AI viruses or with HPAI avian-like A/Cambodia/R0404050/2007(H5N1). However, 21 participants had elevated antibodies against avian-like A/Hong Kong/1073/1999(H9N2), validated with a monoclonal antibody blocking ELISA assay specific for avian H9. Conclusions: Although cross-reaction from antibodies against human influenza viruses cannot be completely excluded, the study data suggest that a number of participants were previously infected with the avian-like A/Hong Kong/1073/1999(H9N2) virus, likely due to as yet unidentified environmental exposures. Prospective data from this cohort will help us better understand the serology of zoonotic influenza infection in a rural cohort in SE Asia. Keywords: Influenza A virus, Avian, Zoonoses, Occupational exposure, Communicable diseases, Emerging, Cohort studies

Background Seeking a noninvasive method to conduct surveillance for respiratory pathogens, we sought to examine the usefulness of 2 types of off-the-shelf aerosol samplers to detect respiratory viruses in Singapore. Methods In this pilot study, we ran the aerosol samplers several times each week with patients present in the patient waiting areas at 3 primary health clinics during the months of April and May 2016. We used a SKC BioSampler with a BioLite Air Sampling Pump (run for 60 min at 8 L/min) and SKC AirChek TOUCH personal air samplers with polytetrafluoroethylene Teflon filter cassettes (run for 180 min at 5 L/min). The aerosol specimens and controls were studied with molecular assays for influenza A virus, influenza B virus, adenoviruses, and coronaviruses. Results Overall, 16 (33.3%) of the 48 specimens indicated evidence of at least 1 respiratory pathogen, with 1 (2%) positive for influenza A virus, 3 (6%) positive for influenza B virus, and 12 (25%) positive for adenovirus. Conclusions Although we were not able to correlate molecular detection with individual patient illness, patients with common acute respiratory illnesses were present during the samplings. Combined with molecular assays, it would suggest that aerosol sampling has potential as a noninvasive method for novel respiratory virus detection in clinical settings.

Background : The One Health (OH) concept, formerly referred to as ‘One Medicine’ in the later part of the 20th century, has gained exceptional popularity in the early 21st century, and numerous academic and non-academic institutions have developed One Health programs. Objectives : To summarize One Health training, research, and outreach activities originating in North America. Methods : We used data from extensive electronic records maintained by the One Health Commission (OHC) ( www.onehealthcommission.org/ ) and the One Health Initiative ( www.onehealthinitiative.com/ ) and from web-based searches, combined with the corporate knowledge of the authors and their professional contacts. Finally, a call was released to members of the OHC’s Global One Health Community listserv, asking that they populate a Google document with information on One Health training, research, and outreach activities in North American academic and non-academic institutions. Results : A current snapshot of North American One Health training, research, and outreach activities as of August 2016 has evolved. Conclusions : It is clear that the One Health concept has gained considerable recognition during the first decade of the 21st century, with numerous current training and research activities carried out among North American academic, non-academic, government, corporate, and non-profit entities. Keywords: One Health; research; training; human; animal; environmental (Published: 29 November 2016) Citation: Infection Ecology and Epidemiology 2016, 6: 33680 - http://dx.doi.org/10.3402/iee.v6.33680

In 2014, a sentinel chicken surveillance for avian influenza viruses was conducted in aquatic bird habitat near Wuxi City, Jiangsu Province, China. Two H7N2, one H5N6, and two H9N2 viruses were isolated. Sequence analysis revealed that the H7N2 virus is a novel reassortant of H7N9 and H9N2 viruses and H5N6 virus is a reassortant of H5N1 clade 2.3.4 and H6N6 viruses. Substitutions V186 and L226 (H3 numbering) in the hemagglutinin (HA) gene protein was found in two H7N2 viruses but not in the H5N6 virus. Two A138 and A160 mutations were identified in the HA gene protein of all three viruses but a P128 mutation was only observed in the H5N6 virus. A deletion of 3 and 11 amino acids in the neuraminidase stalk region was found in two H7N2 and H5N6 viruses, respectively. Moreover, a mutation of N31 in M2 protein was observed in both two H7N2 viruses. High similarity of these isolated viruses to viruses previously identified among poultry and humans, suggests that peridomestic aquatic birds may play a role in sustaining novel virus transmission. Therefore, continued surveillance is needed to monitor these avian influenza viruses in wild bird and domestic poultry that may pose a threat to poultry and human health.

Qinghai Lake is a major migrating bird breeding site that has experienced several recent highly pathogenic avian influenza virus (HPAIV) epizootics. From 2006 to 2009 we studied Qinghai’s wild birds and pikas for evidence of AIV infections. We sampled 941 healthy wild animals and isolated seventeen H7N2 viruses (eight from pikas and nine from wild birds). The H7N2 viruses were phylogenetically closely related to each other and to viruses isolated in Hong Kong in the 1970s. We determined the pathogenicity of the H7N2 viruses by infecting chickens and mice. Our results suggest that pikas might play an important role in the ecology of AIVs, acting as intermediate hosts in which viruses become more adapted to mammals. Our findings of AI infection in pikas are consistent with previous observations and raise the possibility that pikas might play a previously unrecognized role in the ecology of AIVs peridomestic aquatic environments.

Background. Swine can harbor influenza viruses that are pathogenic to humans. Previous studies support an increased risk of human influenza cases among individuals with swine contact. North Carolina has the second-largest swine industry in the United States. Methods. We investigated the spatiotemporal association between influenza-like illnesses (ILIs) and licensed swine operations from 2008 to 2012 in North Carolina. We determined the week in which ILI cases peaked and statistically estimated their week of onset. This was performed for all 100 North Carolina counties for 4 consecutive influenza seasons. We used linear models to correlate the number of permitted swine operations per county with the weeks of onset and peak ILI activity. Results. We found that during the 2009–2010 and 2010–2011 influenza seasons, both seasons in which the pandemic 2009 H1N1 influenza A virus circulated, ILI peaked earlier in counties with a higher number of licensed swine operations. We did not observe this in 2008–2009 or 2011–2012, nor did we observe a relationship between ILI onset week and number of swine operations. Conclusions. Our findings suggest that concentrated swine feeding operations amplified transmission of influenza during years in which H1N1 was circulating. This has implications for vaccine strategies targeting swine workers, as well as virologic surveillance in areas with large concentrations of swine.

While technological advances in animal husbandry have facilitated increases in global meat production, the high density and geographic concentration of food animal production facilities pose risks of infectious disease transmission. The scale of the 2014-2015 highly pathogenic avian influenza H5N2 outbreak in the United States demonstrates the challenges in achieving pathogen control within and around industrial animal facilities using existing technologies. We discuss gaps in current practice in two specific systems within these facilities - ventilation and waste management - which are under-recognized as important drivers of microbial porosity. The development of innovative ventilation systems to reduce influx and efflux of pathogens is critically needed, and cross-sectoral partnerships should be incentivized to do so. Adapting current human biosolid treatment technologies for farm applications, reducing animal stocking density and shifting waste management responsibility from farmer to corporation would reduce risk from current manure management systems. While innovative approaches to functionally altering the industrial food animal production system remain important priorities to promote sustainability, our intention here is to identify gaps within the current system that allow for pathogen emergence and transmission and address specific areas in which technological, administrative or policy changes are necessary to mitigate these risks.

BACKGROUND Modern agricultural practices create environmental conditions conducive to the emergence of novel pathogens. Current surveillance efforts to assess the burden of emerging pathogens in animal production facilities in China are sparse. In Guangdong Province pig farms, we compared bioaerosol surveillance for influenza A virus to surveillance in oral pig secretions and environmental swab specimens. METHODS During the 2014 summer and fall/winter seasons, we used 3 sampling techniques to study 5 swine farms weekly for influenza A virus. Samples were molecularly tested for influenza A virus, and positive specimens were further characterized with culture. Risk factors for influenza A virus positivity for each sample type were assessed. RESULTS Seventy-one of 354 samples (20.1%) were positive for influenza A virus RNA by real-time reverse-transcription polymerase chain reaction analysis. Influenza A virus positivity in bioaerosol samples was a statistically significant predictor for influenza A virus positivity in pig oral secretion and environmental swab samples. Temperature of

Recent research1,2 indicates that occupational exposure to farm animals at several stages of food production may be an important source of exposure to pathogens. The bacterial pathogen Campylobacter jejuni is particularly common in poultry but can also colonize swine and other livestock, including cattle.3 Campylobacter spp. is the most commonly identified bacterial cause of foodborne illness in the United States,4 and campylobacteriosis is the leading cause of bacterial diarrhea worldwide.5 Although food-borne exposure is an important source of Campylobacter infection, case–control studies6,7 have demonstrated significant positive associations between exposure to farm animals, including cattle, and Campylobacter infection. Elevated levels of anti–C. jejuni antibodies have been reported in meat processing workers,8 poultry workers,9 and slaughterhouse workers.2 Infection with C. jejuni is the most frequently identified antecedent to Guillain-Barre Syndrome (GBS), an autoimmune peripheral neuropathy.10–12 GBS is the leading cause of acute flaccid paralysis in the United States and worldwide.13 The incidence of GBS after C. jejuni infection has been estimated to be about 1.17 per 1000 person-years, but certain strains of C. jejuni are more strongly associated with GBS.14,15 Evidence indicates that the mechanism for the association between C. jejuni exposure and GBS involves molecular mimicry between C. jejuni lipo-oligosaccharides and peripheral nerve gangliosides.16–21 Peripheral neuropathy, whether motor or sensory, can have varying degrees of severity and can be due to various causes. In GBS, the mechanism of neuropathy is autoimmune. The two most prominent types of GBS are acute inflammatory demyelinating polyradiculoneuropathy (AIDP), which is the most common type of GBS in North America and Europe, and acute motor axonal neuropathy (AMAN), which is most common in China and Mexico.12,22,23 Weakness is a symptom of both AIDP and AMAN, whereas numbness is more associated with AIDP. In addition to GBS with its acute manifestation, there also is a disease with a longer but heterogeneous course, called chronic inflammatory demyelinating polyradiculoneuropathy, which also exhibits features characteristic of autoimmune disease.24,25 AMAN is most strongly associated with C. jejuni infection, but there is evidence that other forms of autoimmune peripheral neuropathy may be associated with C. jejuni as well.26 Although the symptoms of GBS are often severe, with 80% to 90% of GBS patients becoming unable to walk during their illness, we hypothesize that some people exposed to C. jejuni may experience subclinical, or less severe, symptoms of autoimmune peripheral neuropathy.27,28 Despite the evidence that occupational exposure to animals may be an important source of Campylobacter infection, few studies have examined these exposures to C. jejuni as a risk factor for development of peripheral neuropathy. In 2007, Price et al9 reported for the first time that poultryhouse workers (n = 20) had significantly increased odds of reporting symptoms of peripheral neuropathy compared with community referents (n = 40). Furthermore, among men reporting poultry contact (n = 18), levels of anti–C. jejuni antibodies were significantly higher, and immunoglobulin G antiganglioside autoantibodies associated with autoimmune peripheral neuropathy were increased as compared with male controls (n = 18), but with borderline statistical significance (P = 0.074).9 Davis et al29 used the large sample size of the Agricultural Health Study (AHS) to build on the findings of Price et al, documenting that self-reported work with swine or with both swine and poultry was significantly associated with symptoms of peripheral neuropathy. Campylobacter has been of particular concern in poultry, but there has also been recent attention to the role of cattle as reservoirs of Campylobacter.30 We hypothesize that occupational exposure to cattle may increase the risk of C. jejuni–associated autoimmune peripheral neuropathy, including less severe, or subclinical, peripheral neuropathy. This study examines the association between occupational exposure to dairy or beef cattle and neurologic symptoms in AHS participants.

Zoonotic diseases continue to emerge and threaten both human and animal health. Overcrowded shelters and breeding kennels create the perfect environment for amplified infectious disease transmission among dogs and present a critical opportunity for zoonotic pathogens to emerge and infect people who work in close contact with dogs. Coronaviruses' widespread prevalence, extensive host range, various disease manifestations and increased frequency of recombination events all underline their potential for interspecies transmission (Methods Mol. Biol. 2008, 454, 43). The objectives of this study were to determine whether people with occupational contact with dogs were more likely to have antibodies against canine respiratory coronavirus (CRCoV) compared to persons with no dog exposure. A seroepidemiological cohort study was completed, for which 302 canine-exposed and 99 non-canine-exposed study subjects enrolled in the study by providing a serum sample and completing a self-administered questionnaire. A competitive enzyme-linked immunosorbent assay (ELISA) was developed to detect human antibodies against CRCoV while controlling for cross-reacting antibodies against the human coronavirus OC43. All study subjects were negative for antibodies against CRCoV by this competitive ELISA. This study supports the premise that humans are not at risk for CRCoV infections; however, infrequent cross-species transmission of CRCoV cannot be ruled out.

Summary Marine mammals evoke strong public affection as well as considerable scientific interest. However, the resultant close contact with marine wildlife poses human health risks, including traumatic injury and zoonotic disease transmission. The majority of zoonotic marine mammal diseases result in localized skin infections in man that resolve spontaneously or with appropriate medical therapy. However, other marine mammal zoonoses, if left untreated, induce life‐threatening systemic diseases that could pose public health risks. As the number of zoonotic diseases rises, the diagnosis of and treatment for these emerging pathogens pose special challenges requiring the expertise of physicians, veterinarians and wildlife biologists. Here, we provide a comprehensive review of the bacterial, viral and fungal marine mammal zoonotic diseases that we hope will be utilized by public health professionals, physicians, veterinarians and wildlife biologists to better understand, diagnose and prevent marine mammal zoonotic diseases.

To the Editor: From early 2013 (1) through November 2014, >460 human cases of laboratory-confirmed avian influenza A(H7N9) virus infection occurred in China. Although human-to-human transmission of subtype H7N9 virus is not common, evidence has been reported of probable transmission among several family clusters (2), between 2 household contacts (3), and between a doctor and an infected patient (4). Taken together, these observations suggest that family members, health care providers, and other close contacts (hereafter called contacts) of H7N9-infected persons may be at risk for infection. In China, national guidelines regarding H7N9-infected patients call for observation of contacts for 7 days after exposure for signs and symptoms of infection and, if any occur, collection of throat swab specimens for testing by molecular assays (5). The guidelines do not call for serologic testing. Because human avian influenza infections may be mild or asymptomatic, we sought to determine whether serologic testing would show evidence of H7N9 virus infection among contacts of infected persons during the 2013–2014 epidemic in China. Contacts were defined in accordance with China’s guidelines for prevention and control of human H7N9 virus infection (5,6). The institutional review board of Wuxi Center for Disease Control and Prevention, Wuxi, Jiangsu Province, China, reviewed and approved this study. During the epidemic, we recruited contacts of patients in Wuxi and collected throat swab specimens when signs or symptoms of infection developed; serum samples were collected 2–3 weeks later. Swab specimens were tested for H7N9 virus by using real-time reverse transcription PCR (7). Serum samples were tested for antibodies against hemagglutinin antigens of 3 avian influenza viruses (A/Anhui/1/2013 [H7N9], A/Anhui/1/2005 [H5N1]-RG5, and A/chicken/Jiangsu/1/00 [H9N2]) (8) by using a horse erythrocyte hemagglutination inhibition (HI) assay and against the hemagglutinin antigens of 2 seasonal influenza viruses (A/California/07/2009 [H1N1] and A/Victoria/210/2009 [H3N2]) by using a turkey erythrocyte HI assay. Serum samples with HI titers >1:40 against H7N9 virus were confirmed positive by microneutralization assay. Ten laboratory-confirmed human infections with H7N9 virus occurred in Wuxi during March 29, 2013–May 15, 2014. In total, 225 contacts of 7 H7N9-infected patients were enrolled in the study (Table); contacts included 30 family members; 177 health care workers (54 physicians, 119 nurses who provided patient care with standard precautions, 2 hospital attendants, and 2 nurse assistants who provided services related to patient care, safety, and comfort, including anxiety relief, and medical observation); and 18 other contacts (8 friends who visited the patient in the hospital, 2 patients who shared the same room, and 8 patients who shared the same hospital area). The contacts of 3 other H7N9-infected patients declined to participate in the study. Table Demographic characteristics and HI antibody titers against influenza subtype H7N9, H5N1, H9N2, H1N1, and H3N2 viruses among close contacts of avian influenza A(H7N9)–infected persons, China, 2013–2014* Serologic assay results showed that, 14–28 days after their earliest exposure to an H7N9-infected patient, 22 (9.8%) contacts had elevated HI antibody titers (>1:40) against H7N9 virus; titers were 1:40 for 17 contacts and 1:80 for 5 contacts. Positive results for all 22 serum samples were validated by microneutralization assay; 15 (68.2%) samples had microneutralization antibody titers of >1:10 against H7N9 virus antigen (Table). Of the contacts with an HI titer of >1:80 and microneutralization titer of >1:40, 3 were nurses, 1 was a nurse assistant, and 1 was a family member (a patient’s daughter). All 5 of these contacts had antibody titers of 1:80 to seasonal H1N1 virus, 3 had titer of 1:80, and 1 each had titer of 1:160 or 1:640. Of the 225 contacts, 108 had HI titers >1:80 against seasonal H3N2 virus (1:80 for 63 contacts, 1:160 for 27 contacts, 1:320 for 9 contacts, and >1:640 for 8 contacts). All contacts had influenza subtype H5N1 and H9N2 antibody titers of

Genetically similar, the avian metapneumovirus (aMPV) and the human MPV (hMPV) are the only viruses in the Metapneumovirus genus. Previous research demonstrated the ability of hMPV to cause clinical disease in turkeys. In this controlled, cross-sectional, seroepidemiological study, we examined the hypothesis that aMPV might infect humans. We enrolled 95 adults occupationally exposed to turkeys and 82 nonexposed controls. Sera from study participants were examined for antibodies against aMPV and hMPV. Both in bivariate (OR=3.2; 95% CI: 1.1-9.2) and in multivariate modelling adjusting for antibody to hMPV (OR=4.1; 95% CI: 1.3-13.1), meat-processing workers were found to have an increased odds of previous infection with aMPV compared to controls. While hMPV antibody cross-reactivity is evident, these data suggest that occupational exposure to turkeys is a risk factor for human infection with aMPV. More studies are needed to validate these findings, to identify modes of aMPV transmission, and to determine risk factors associated with infection.

Background. Regions of Thailand reported sporadic outbreaks of A/H5N1 highly pathogenic avian influenza (HPAI) among poultry between 2004 and 2008. Kamphaeng Phet Province, in north-central Thailand had over 50 HPAI poultry outbreaks in 2004 alone, and 1 confirmed and 2 likely other human HPAI infections between 2004 and 2006. Methods. In 2008, we enrolled a cohort of 800 rural Thai adults living in 8 sites within Kamphaeng Phet Province in a prospective study of zoonotic influenza transmission. We studied participants’ sera with serologic assays against 16 avian, 2 swine, and 8 human influenza viruses. Results. Among participants (mean age 49.6 years and 58% female) 65% reported lifetime poultry exposure of at least 30 consecutive minutes. Enrollees had elevated antibodies by microneutralization assay against 3 avian viruses: A/Hong Kong/1073/1999(H9N2), A/Thailand/676/2005(H5N1), and A/Thailand/384/2006(H5N1). Bivariate risk factor modeling demonstrated that male gender, lack of an indoor water source, and tobacco use were associated with elevated titers against avian H9N2 virus. Multivariate modeling suggested that increasing age, lack of an indoor water source, and chronic breathing problems were associated with infection with 1 or both HPAI H5N1 strains. Poultry exposure was not associated with positive serologic findings. Conclusions. These data suggest that people in rural central Thailand may have experienced subclinical avian influenza infections as a result of yet unidentified environmental exposures. Lack of an indoor water source may play a role in transmission.

In this issue of Clinical Infectious Diseases, Forgie et al [1] offer the most compelling documentation to date of the introduction of a human influenza virus into a pig herd and subsequent related influenza epidemics in both pig and human populations. Although their article could be criticized, because nasal swab specimens from pigs were not taken to prove that the virus was not already enzootic before the likely human index case, circumstances and investigational data strongly support the authors’ interpretation of the data. The event occurred at a closely monitored Canadian swine research facility, where biosecurity and laboratory support had protected the pig herd from other common swine respiratory infections. The authors’ position that this was an acute and explosive human introduction of pandemic influenza A (H1N1) virus (pH1N1) in a modern swine facility was supported by the chronology of the signs in the pigs and signs and symptoms in the swine workers, the serologic investigation in the workers, the molecular detection of pH1N1 in pigs and the workers, and the subsequent genomic comparisons of the influenza A isolates. The authors’ report is also remarkable because it demonstrates that preclinical asymptomatic shedding of influenza A virus can circumvent even our best policies and biosecurity infrastructure. As we have clearly seen with the rapid international and interspecies spread of pH1N1, nonpharmaceutical interventions may slow transmission of such novel influenza A virus strains, but in the long term, such strains beat our best efforts. The report reinforces our understanding that this particular strain is often associated with subclinical infections in both humans and pigs. The authors’ observation that 94% of pH1N1-infected pigs had no clinical signs is consistent with a recent report in which 64% of influenza A virus–naive Norwegian swine herds showed no signs of infection after pH1N1 was introduced[2]. Furthermore, pH1N1 infections in pigs are transient, and experts agree that they do not threaten the safety of meat consumption. This supports the US pork industry’s position that influenza A virus is not a substantial problem for the swine industry; infections are not reportable and, therefore, not a matter of their concern. In fact, misunderstandings of the public health risk of pH1N1 detection in pigs caused considerable fiscal damage to pork production at the beginning of the 2009 H1N1 pandemic. One can understand why the pork industry is unlikely to adapt influenza surveillance policies like those of the US poultry industry. The figure provided by Forgie et al [1] clearly documents what other reports have only hinted at—the explosive nature of viral transmission among pigs in modern, confined animal feeding operations (CAFOs). We know from limited veterinary studies of Canadian pigs that swine influenza virus strains are most prevalent in areas where large herds of pigs are densely confined [3]. This is biologically plausible, because large CAFOs with numerous pig barns have weekly introductions of young immunologically naive pigs necessary to sustain influenza A infection. Despite various biosecurity and animal husbandry measures in these large facilities (eg. ‘‘all in all out’’ cohorting), influenza A virus strains often are detected in these herds. Mathematical models and epidemiological studies of swine workers have suggested that workers can serve as a bridging population to introduce the influenza A virus strains that are being amplified in the CAFOs to their surrounding human communities [4–7]. With assumptions similar to that of the 1918 pandemic virus, Saenz et al [4] found that such bridging could markedly accelerate influenza virus Received 14 September 2010; accepted 17 September 2010. Correspondence: Gregory C. Gray, Dept of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Box 100188, Gainesville, FL 32610 (gcgray@phhp.ufl.edu). Clinical Infectious Diseases 2011;52(1):19–22 The Author 2011. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals. permissions@oup.com. 1058-4838/2011/521-0001$37.00 DOI: 10.1093/cid/ciq051

Industrial poultry workers may be at elevated risk of avian influenza infection due to intense occupational contact with live poultry. Serum samples from poultry workers and community members in the Delmarva Peninsula, one of the densest regions of poultry production in the United States, were analyzed for antibodies to strains of five avian influenza subtypes using microneutralization assays. No evidence of infection was found, suggesting inefficient transmission to humans or the absence of virus in these premises. Continued serological surveillance of workers in industrial food animal facilities is necessary to prevent the transmission of influenza A viruses.