U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Virus and Prion Research: Ames, IA
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area Ames, Iowa National Animal Disease Center Virus and Prion Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Brockmeier, Susanitem
                                            Loving, Crystalitem
                                            Register, Karenitem
                                            Nicholson, Tracyitem
                                            Bayles, Darrellitem
                                            PHILLIPS, GREGORY - Iowa State University
  Submitted to: American Association of Swine Veterinarians Annual Meeting
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 9/1/2009
                                    Publication  Date: 3/6/2010
                                    Citation: Brockmeier, S., Loving, C.L., Register, K.B., Nicholson, T.L., Bayles, D.O., Phillips, G.J. 2010. Studies of pathogenesis, transmission, and heterologous protection of four isolates of Haemophilus parasuis in a highly susceptible swine population [abstract]. 2010 American Association of Swine Veterinarians Annual Meeting. p. 127-129.Interpretive Summary:
                                Technical Abstract: Pigs from an experimental herd that is free from known swine pathogens were used in a study with several Haemophilus parasuis isolates in an effort to identify isolates of varying virulence to sequence in order to determine virulence factors for this pathogen.  Each of 4 groups of 5 pigs each varying in age from 36 to 68 days were inoculated with a different isolate of H. parasuis intranasally (SW114, 12939, MN-H, and 29755), with a fifth group of 5 pigs serving as sham inoculated controls.  Three of the 4 isolates caused systemic disease, with pigs showing signs of disease (lameness, depression, neurologic signs) from 1 to 5 days post infection.   All 5 pigs from the 12939 and 4/5 pigs from the 29755 and MN-H groups had to be euthanized or died peracutely.  H. parasuis was isolated from systemic sites (pleura, peritoneum, joint, and/or meninges ) from 12/13 of these pigs.  One pig each from the 29755 and the MN-H group and all the SW114 pigs remained healthy with no clinical signs of disease; however, H. parasuis was isolated from nasal swabs from these pigs indicating they were colonized.  One control pig each was placed into the room with the lone survivor from the 29755 and the MN-H groups to determine whether transmission would occur.   The contact pig placed in with the MN-H pig became ill 5 days later, was euthanized and had lesions of full blown polyserositis.  The contact pig placed with the 29755 pig became lame 7 days later, was euthanized and H. parasuis was isolated from the joint.  The 2 survivors from the initial 29755 and MN-H challenge remained healthy.  The 5 surviving SW114 pigs and the surviving 29755 and MN-H pigs were then rechallenged with the 12939 isolate to determine if they would be protected from a heterologous virulent strain.  The 3 surviving control pigs were also challenged with 12939.  All three control pigs developed systemic disease similar to the initial challenge, but all pigs previously challenged with SW114, 29755, and MN-H remained healthy.  Thus, pigs within susceptible groups can remain healthy and serve as reservoirs for transmission, and heterologous protection using avirulent isolates is possible.  Draft genome sequences have now been obtained from 3 of these isolates of H. parasuis.  Preliminary comparisons suggest considerable variation in the gene complement of distinct strains.  Bioinformatics approaches are being used to discover genes that are conserved among strains as well as those that are unique.  These results will provide a basis for testing the role of potential virulence genes in swine infection studies and may also allow development of detection assays that discriminate between strains of high and low virulence.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov