assess the broad-scale population structure of feral 

 pigs in South Texas and to evaluate recolonization 

 after local removals. 



Preliminary results indicate that pig populations 

 display a moderate degree of population structuring 

 at a large scale (-120 mi^), suggesting that 

 at broad geographic scales, populations are 

 functionally independent of each other. However, 

 genetic similarity was not a simple function of 

 geographic distance, implying that movement and 

 dispersal are not equal among populations. This 

 may be due to the presence of terrain features that 

 promote dispersal (e.g., river systems) or inhibit it 

 (e.g., urban areas, vast areas of farmland). 



At a local scale, feral pig samples taken before and 

 after removal were genetically different, indicating 

 rapid recolonization into the controlled area. 

 Overall, results indicate that knowledge of feral 

 pig population structure in some areas of South 

 Texas could be used to improve control efforts. But 

 high rates of movement and dispersal would likely 

 require control efforts over a very broad region, 

 possibly an entire watershed. Attempts will be 

 made to identify fine-scale genetic structure and 

 landscape features that could be used to focus 

 management efforts. 



Surveillance for the Pathogenic H5N1 Strain 

 of A! in Feral Hogs — An influenza pandemic is 

 currently regarded by many health officials as a 

 significant threat to global public health. The next 

 influenza pandemic will likely be caused by a virus 

 that possesses surface proteins to which humans 

 have no immunity. Previous influenza pandemics 

 occurred via genetic reassortment in an animal 

 coinfected by avian and human influenza virus 

 strains. One likely "mixing vessel" is the feral hog. 



The invasive feral hog exists across North America, 

 and large populations inhabit areas frequented 

 by bird species that serve as influenza reservoirs. 

 NWRC scientists conducted surveillance on feral 

 hogs for the presence of avian-origin influenza 

 viruses (including the highly pathogenic H5N1) 

 in Texas, a State where millions of migratory and 



resident waterfowl and shorebirds winter among a 

 large population of feral hogs. 



Nasal swabs and blood serum from hunter- 

 harvested animals and nuisance animals removed 

 by Texas WS were obtained during 2006 and 2007. 

 Samples were screened for all 16 hemagglutinin 

 and 9 neuraminidase subtypes of the influenza 

 virus. As of October 2007, more than 600 samples 

 had been tested with no avian-origin influenza 

 viruses detected. 



Early detection is chtical for disease management 

 strategies to be successful. This study is an 

 important step in understanding the dynamics of 

 this highly publicized zoonotic disease and will 

 aid in understanding potential routes of human 

 exposure. 



High Rates of Multiple Mating in Feral Pigs: 

 Risk of Disease Transmission — Feral pigs 

 are susceptible to diseases that affect wildlife, 

 livestock, and humans — a fact that raises serious 

 concerns about the role these animals play in 

 the maintenance and transmission of disease. 

 However, predictions of disease transmission by 

 feral pigs are hampered by a lack of information on 

 their ecology and behavior. As a result, estimates of 







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Scientists have discovered a high rate of promiscuity among 

 feral pigs. Approximately 48 percent of litters are sired by 

 more than one boar, suggesting that the risk of transmitting 

 diseases that are spread by direct contact is significant during 

 reproductive behavior. 



28 Developing Methods 



