Viral Zooanthroponoses from Turkeys to Humans

1. Viral Zooanthroponoses from Turkeys to Humans Abstract Acknowledgements Preliminary Results Discussion Materials & Methods Introduction Ghazi Kayali, MPH, Ernesto J. Ortiz, MD, MPH, and Gregory C. Gray, MD, MPH Center for Emerging Infectious Diseases, The University of Iowa College of Public Health, Iowa City, Iowa, USA • This is a cross-sectional seroepidemiological study of 200 individuals exposed to turkeys and 100 controls. • More than 150 participants enrolled thus far from churches, grocery shops, county fairs, feed mills, homes, and farms. • Enrollees complete a specifically tailored questionnaire that captures demographic, health, and occupational exposures data. • Sera will be tested for antibodies against the avian viruses under study and their human counterparts to rule out cross-reactivity of antibodies. • The assays that will be used are summarized in Table. • The avian pneumovirus (aMPV) and the human metapneumovirus (hMPV) are the sole members of the Metapneumovirus genus and are very similar at the molecular level. This suggests the possibility that they might infect across species. • There is evidence showing human infections by swine an. avian influenza viruses with high and low pathogenicity. • Zoonotic infections of adenovirus in humans are rarely studied. Very recently, Xiang et al. reported potential cross-species transmission of adenovirus when antibodies against a chimpanzee adenovirus was detected in humans. • This pilot study will explore evidence that turkey workers have been occupationally exposed to aMPV, AI, and HEV. This study will attempt to answer the following research questions: • What is the seroprevalence of aMPV/C, AI, and HEV in exposed and non-exposed human populations? • What risk factors are associated with aMPV/C, AI, and HEV infections in humans? • In a controlled study, 80 two-week-old turkey poults were inoculated with one of 4 different genotypes of hMPV. All 4 genotypes caused transient clinically disease among the birds. The infected birds showed nasal discharge and sinus swelling while the controls did not (Figure 1). Furthermore, RT-PCR identified hMPV in the birds’ tissues. • Among 14 turkey-exposed agricultural workers, those who had the most intense exposure to turkeys also had the strongest evidence for previous infection with aMPV (by ELISA OD reading, Figure 2). This association was statistically significant suggesting that workers exposed to turkeys are being infected by aMPV. • Data collected from a pilot study of 38 turkey processing plant workers showed a positive relationship between years of exposure and ELISA OD (Figure 3). In 2001, Dutch scientists described a newly recognized human respiratory pathogen, the human metapneumovirus (hMPV). This virus has since been found to cause infections in people of all ages throughout the world. Realizing that hMPV was most similar to a turkey pathogen, the avian pneumovirus (aMPV), the Dutch experimented to learn if hMPV would replicate in turkeys but their studies failed to show infection. Since then we have shown that all 4 recognized genotypes of hMPV cause clinical infections in turkeys and that there is serological evidence among 14 Iowans who reported occupational exposures to turkeys, that those with the longest exposures are more likely to have antibodies against aMPV. In this proposed epidemiologic study we seek to further explore evidence that persons with occupational exposure to turkeys are at risk of infection with turkey viruses. Specifically, we seek to enroll 200 US adults with turkey exposure and 100 controls without turkey exposure in a cross-sectional study for serological evidence of previous infection with aMPV, avian influenza (AI) viruses, and the hemorrhagic enteritis virus (HEV). It is our central hypothesis that such zoonoses will be relatively frequent among Midwestern turkey workers, and that we will be able to identify important risk factors associated with occupational aMPV, AI and HEV infection in humans. This study is unique in that no other such research among turkey workers has ever been conducted. Our long term goal is to examine hypotheses such as this one. Where we have evidence of occupational risk for zoonotic pathogen transmission to man, we seek to develop diagnostics to better detect such pathogens and to implement interventions to prevent their infection risk to man. • Results from this study may yield a better understanding of occupational associated zoonotic viral infections among turkey workers and shed light on the current health and safety practices that turkey workers follow. • Further research may be warranted to develop better diagnostics, preventive interventions, treatments, and vaccines. aMPV and HEV viruses. antisera, and EIA protocols were kindly provided by Dr. Kakambi Nagaraja from the School of Veterinary Medicine, University of Minnesota. Figure 1. Clinical signs of turkey poults exposed to human metapneumovirus, showing nasal discharge (solid arrows) and swollen eyelids (dotted arrows). Velayudhan BT, Nagaraja KV, Thachil AJ, Shaw DP, Gray GC, Halvorson DA. Human metapneumovirus in turkey poults. Emerg Infect Dis 2006;12:1853-9.