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
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home 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
                                            DEMAREZ, TINE - 1265-20-00item
                                            LIDDELL, S. - 1265-20-00item
                                            Dubey, Jitenderitem
                                            Jenkins, Markitem
                                            Gasbarre, Louis
  Submitted to: International Journal for Parasitology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 9/6/1999
                                    Publication  Date: N/A
                                    Citation: N/AInterpretive Summary: Neospora caninum is the major cause of abortion in cattle in many parts of the world.  Recently, it has been shown that dogs excrete the infective stage (oocyst) of this parasite and thus serve as a host for this parasite.  The aim of this study was to investigate whether calves can be infected with these oocysts from Neospora and if calves develop antibodies  or cells which recognise Neospora antigens.  Before infection, none of the calves showed antibodies which recognised Neospora antigens and none of them had cells reacting to Neospora antigens.  However, after 1 week of infection the infected calves had cells that recognized antigens from Neospora and within 2 and 4 weeks also antibodies against Neospora were also  detected. The presence of antibodies and cells in the infected animals, and parasite DNA in the brain and spinal cord, indicate that the cattle were infected upon receiving  N. caninum oocysts collected from  dogs.  In contrast calves not given oocysts showed none of these changes. To our knowledge this is the first report of an experimental infection of calves with Neospora oocysts.
                                Technical Abstract: Neospora caninum has been identified as a major cause of abortion in cattle in a number of countries throughout the world.  Until the recent demonstration that dogs can serve as a definitive host of this parasite, it was not possible to study the infection in cattle orally exposed to oocysts.  The aim of this study was to investigate the  potential of N. caninum oocysts to infect calves and to define initial immune responses that arise after oral infection.  Seven calves were fed approximately 104-105 N. caninum oocysts, three calves served as uninfected controls.  Before infection, all calves were serologically negative for anti-Neospora antibodies and the calves were non-reactive to Neospora antigen in an in vitro lymphocyte proliferation assay. Peripheral blood lymphocytes from inoculated calves were able to mount in vitro proliferative responses to crude N. caninum antigen extract as  early as one week p.i.  Within 2 and 4 weeks p.i. Neospora-specific IgG1 and IgG2 antibodies were detected by IFAT and ELISA in serum from infected calves but not from sham-infected calves. The continued presence of reactive cells in the blood, spleen and mesenteric, inguinal, bronchial lymph nodes was seen as late as 2.5 months p.i., and parasite DNA was detected in the brain and spinal cord of the infected animals by PCR, indicating that the cattle were infected by oral inoculation of N. caninum oocysts collected from dogs, and that the animals were systematically sensitised by parasite antigen.


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