Activities

Recent major activities highlight the APHI’s unique work in fulfilling the mission of a land grant institution such as Colorado State University and emphasize the Institute’s excellent record of contribution to and collaboration with many state, regional, national, and international entities.

Major Activities by Topic

Transmissible Spongiform Encephalopathies (TSEs)
Equine Infectious Diseases 
Mycobacterial Infections of Animals  
Food Safety and Risk Analysis  
Antimicrobial Resistance  
Global Epidemiology  
Other Diseases and Topics 
Teaching and Outreach  

Transmissible Spongiform Encephalopathies (TSEs)

Chronic wasting disease in deer and elk

• Commercial screening assays: In 2002, a study was initiated to validate the adaptability of commercially available screening tests for bovine spongiform encephalopathy (BSE) in the detection of the abnormal protease-resistant pathogenic protein (PrP^CWD) associated with chronic wasting disease (CWD).  Based on APHI study results, one of the commercial screening tests, BioRad-ELISA, was recommended for use in testing deer and elk brains during the 2002 hunting season in Colorado and was adapted and implemented by Colorado Division of Wildlife as part of their routine screening procedure.  The second phase of the validation of these commercial BSE screening tests for CWD has been initiated.  Groups from the game and livestock industries as well as diagnostic companies have expressed their interest in this study and have contributed to the funding of this study.

• Surveillance system development: APHI researchers participated with scientists from the Colorado Division of Wildlife, Colorado Department of Agriculture, CSU- Veterinary Diagnostic Laboratory, and the US Department of Agriculture, Animal and Plant Health Inspection Service (USDA:APHIS) in designing and implementing a surveillance system for CWD in free-ranging cervids in Colorado.  The system will be considered a model for other states with similar wildlife disease issues.

• Diagnosis and prevention:  A multi-institutional project combining basic and applied research activities in the United States and Switzerland was initiated with the goals of (1) developing methods to detect very low levels of PrP^CWD in body fluids accessible for collection from live animals, (2) assaying other tissues of deer that may be important to potential risk associated with human consumption of venison, and (3) using new vaccine te deer and elk.  This research couldds for CWD and other prion infections.

Food safety and TSEs

• Diagnostic test technology transfer.  In a collaborative effort with the Swiss Federal Veterinary Office (BVET), personnel from the APHI Laboratory were trained to develop and use the western blot (WB) test currently being used in Switzerland to test food products for the presence of central nervous system tissue.  This test is currently being optimized in the APHI Laboratory.  Identification of CNS tissue in food products is a crucial step in reducing human risk should BSE become a problem in the USA

Equine Infectious Diseases

West Nile Virus (WNV)

• Epidemiology in Colorado and Nebraska Equids: After WNV infection was first confirmed in Colorado in 2002, APHI initiated a follow-up telephone survey of owners of equine WNV cases in Colorado and Nebraska in collaboration with the animal health officials in both states.  The goal of this study was to determine the long-term outcome of WNV-affected horses as well as the effectiveness of treatments given and the vaccination status of horses confirmed with WNV infection.  APHI also assisted the two state veterinarians’ offices in conducting a follow-up study with veterinary practitioners to determine the cost and types of treatments provided to equine WNV cases in Colorado and Nebraska during 2002. APHI personnel worked with an agricultural economist from the USDA:APHIS:VS to develop an economic estimate of WNV on the equine industries in Colorado and Nebraska.  Information sheets on the economic impact of equine WNV and the outcome of equine WNV cases have been written and widely distributed to the equine industry by the public relations office of CSU.  These information sheets were also posted on the APHI webpage.  APHI personnel have conducted numerous interviews with the press and have been featured on several radio and television broadcasts based on these studies.

• APHI personnel were requested to work with the Centers for Disease Control in the development of a WNV educational video.  This video, finalized in August 2003, is being distributed by the Rotary.

• Antibody titers in vaccinated and naturally infected horses: A study has been initiated in association with the CSU Veterinary Teaching Hospital Ambulatory Service to compare antibody titers of WNV in vaccinated horses to those in horses recovering from natural infection, as well as to compare these titers after one year. Serum sample testing was performed at the USDA:APHIS: National Veterinary Services Laboratories.

Vesicular Stomatitis(VS)

• Test development:  A one-step single tube multiplex reverse-transcriptase PCR test for detection of the VS virus in biological samples and insects has been developed and validated.  This test, more sensitive and efficient than conventional virus culture methods, has been applied to experimentally infected rodents from Costa Rica and will be used to test samples collected from horses in Colorado and New Mexico monitored for the last three years through an APHI sentinel herd study.

• Molecular epidemiology:  Molecular "fingerprinting" is being used in conjunction with Geographical Information Systems (GIS) analysis to increase understanding of spread of the VS virus.  These data are used to generate and test hypotheses about the endemicity and ecology of VS virus in various regions of the USA, Mexico, and Central America.

• Serological data:  The APHI research team has demonstrated serological evidence of VS virus activity during non-outbreak years in a specific equine population that was monitored for three years in the Southwestern USA.

Equine clostridiosis

• Toxoid development  Development of a toxoid against equine clostridiosis for use in broodmares prior to foaling has been investigated.

• Test development and validation:  A test to identify clostridial alpha, beta 1 and beta 2 toxins in clinical samples was developed and is now being validated.

Equine Infectious Upper Respiratory Disease (IURD)

• APHI was involved in a field-based investigation of IURD due to Streptococcus equi in wild horses and burros (WHB) that was funded by the US Bureau of Land Management (BLM).  The study entailed tracking of horses from the time of removal from the free-ranging environment through the adoption phase.  APHI personnel also obtained funding from the College Research Council for the development of two tests that would aid them in determining sources of Streptococcus equi infection in both WHB and domestic horses.  An ELISA for detection of antibody to the M-protein of Streptococcus equi has been validated in the APHI laboratory and grants have been submitted to allow field-based evaluation of this test in predicting severity of disease in domestic horses exposed to Streptococcus equi.

Mycobacterial Infections of Animals

Mycobacterium bovis and Mycobacterium tuberculosis

• Serological testing:  APHI is collaborating in the current effort to develop and validate a serological test for bovine tuberculosis screening as part of the USDA Tuberculosis Control Program.  APHI researchers participated in the investigation of tuberculosis in dairy herds in Michigan, Texas, and California.  Several serological assays were implemented and validated in the APHI Laboratory to assist in this investigation.

• Polymerase Chain Reaction (PCR) development and testing:  A one-tube nested PCR for detection of M. bovis was developed and validated using frozen lymph nodes collected from slaughter cattle in Michigan, Texas, and California.  This test, more sensitive than previous tests for detecting animals shedding the bacterium, would allow rapid diagnosis and elimination of infection from dairy herds as well as have a potential use in the national slaughterhouse surveillance system.  Results of the tests were shared with both state and federal animal health authorities in order to assist in investigations of the disease and determine its source.

• Non domestic species:  Testing and validation of a multiple-antigen ELISA to detect Mycobacterium spp. in captive elephants and other non-domestic species is progressing.

• Molecular epidemiology:  Molecular "fingerprinting" of isolates was used to help identify sources of M. bovis infection and promote increased understanding of local, regional, and global transmission of bovine tuberculosis.

Mycobacterium avium subspecies paratuberculosis (Johne’s disease)

• Diagnostic strategies: Diagnostic strategies for determining paratuberculosis infection in young cattle were identified and evaluated.  Findings from this project would be useful in allowing early identification of infection in dairy cattle to decrease disease spread.

• PCR development and testing:  A one-tube nested PCR for the detection of M. avium subspecies paratuberculosis was developed and validated.  This test is more sensitive and specific than previously used tests, and would allow the elimination of infection from a herd before the disease can spread.

Food Safety and Risk Analysis

• E. coli O157:  Seven commercial immunoassay kits were evaluated for the detection of E. coli O157 in spiked bovine fecal samples.  The validation of a rapid screening test for E. coli O157 contamination is important in the control of that zoonotic pathogen in meat that is intended for human consumption.

• Fecal sampling protocols:  The feasibility of using pooled cattle fecal samples collected from the pen floor as surrogates for individual animal fecal samples was assessed using the antimicrobial drug resistance patterns of non-type specific E. coli from feedlot cattle as an outcome model.  The validation of protocols for using pooled pen floor fecal samples for surveillance and monitoring would greatly improve practicability and reduce the costs associated with testing.

• Analytical methods:  Analytical methods for determining risk factors for food safety pathogens were explored using Listeria monocytogenes as a model.  This work was done in collaboration with the Swiss Federal Veterinary Office (BVET).  Incidence and associated risk factors for L. monocytogenes contamination of dairy products and imported meat and fish products in Switzerl and were examined using epidemiological analytical models. These data were selected due to their comprehensive inclusion of several factors and consistency in the collection of data.

• Modeling prevalence in clusters:  A model, based on both maximum likelihood and Bayesian approaches that allowed for clustering within pooled samples, was developed through collaboration with researchers from the University of California at Davis.  These approaches require additional scientific input to model the dependence and allow for uncertainty about test sensitivity and specificity.  It was determined that when dependence (either spatially or temporally) is large, prevalence is underestimated compared with an analysis that assumes independence.  The model was applied to estimation of the prevalence of Salmonella enteritidis in shell eggs.

• Modeling transmission:A stochastic model of transmission of toxoplasmosis (T. gondii) infection has been developed through collaboration with researchers from the University of California at Davis.  This model is a modification of a previous deterministic model of one collaborator (Nohra Mateus Pinilla), which is based on the concept of environmental contamination via T. gondii oocysts from cats.  Water, feed, carcasses and rodents are considered as possible sources of infection for pigs.  The model is being validated with T. gondii serologic data from the USDA:APHIS:VS National Animal Health Monitoring System Swine 2000 Study.

Antimicrobial Resistance

• The ecology of antimicrobial resistance in bacteria of animal origin and from animal environments was the focus of three major federal grants (totaling more than $1,000,000) received by APHI faculty members during the last three years.  As well, APHI researchers have secured funding to gather corresponding antimicrobial resistance data from intensive livestock raising units in South America to compare to data from intensive livestock-raising units in the USA.

Global Epidemiology

• Researchers from APHI have continued to collaborate with the USDA:APHIS:Veterinary Services (VS), Centers of Epidemiology and Animal Health (CEAH; Fort Collins, Colorado) in the design and implementation of several projects related to surveillance and risk analysis for economically important infectious diseases.  Many national and international scholars and other researchers in animal health disciplines have worked on site at APHI and at the CEAH.  This has resulted in the development of an extensive national and international collaborative network to promote a scientifically-based approach to the trade of animals and animal products, and development of collaborative projects with other institutions worldwide in the field of infectious animal diseases and epidemiology.

• In collaboration with the CSU Veterinary Diagnostic Laboratory and USDA:Agricultural Research Service (ARS):Foreign Animal Disease Laboratory (FADL; Plum Island, NY), APHI researchers are working to develop and validate rapid and reliable diagnostic assays for important foreign animal diseases that are identified as priorities for a national plan to prevent bio- and agriculture terrorism acts.  The FADL has formalized an agreement with APHI to collaborate in the area of epidemiology of infectious animal diseases for this research.

• Some APHI scientists are active in assisting developing countries in formulating and implementing regional and national animal health monitoring and disease control programs, and are participants in national and international coalitions for the promotion of animal health and development of control regulations for specific diseases of global economic importance.  These activities serve to promote a positive collaborative spirit between international researchers and the US, maintain the position of these researchers as experts in these topics, continually update and advance the knowledge of international animal disease issues and solutions, and offer a venue for promotion of national interests in import/export regulations and markets.

Other Diseases and Topics

• Brucellosis in bison:  New oral formulations of RB51 brucellosis vaccine are being developed and tested for use in bison and wild ungulates in Yellowstone National Park and elsewhere.

• Biosecurity:  A nationally-recognized biosecurity program for domestic animal facilities and veterinary hospitals/clinics, was developed and initiated by APHI faculty members.  They have assisted other veterinary clinics in the development of their biosecurity plans and have given continuing education lectures to veterinarians. These biosecurity plans and standards of operation will also assist national and state animal health authorities in securing the national food supply and the health of livestock in the US.  A collaborative link was established with theColorado State University - High Plains Intermountain Center for Agricultural Health and Safety (HICAHS) in order to utilize their expertise in designing and implementing agriculture security systems for livestock operations.

• Risk management in aquaculture:  This project is part of a partnership between USDA/Risk management agency, Mississippi State University, and Colorado State University. The main purpose of the study is to assess the feasibility of disease spread simulation models as risk management tools to be used in health insurance programs for fish farms in the United States of America. The project will include research on available baseline health data on farmed fish in the US, characterization of aquaculture production systems and species in the context of transmissible diseases, and risk assessments on different economically important infectious diseases that could potentially affect farmed fish in the US including an assessment of the consequences of such diseases in the production systems, using disease spread simulation models.

Teaching and Outreach

• Epidemiology training for USDA Veterinary Officers:  APHI personnel provide teaching expertise for the delivery of epidemiology training.  A new initiative involves the creation of on-line course material.

• International Meeting of Veterinary Epidemiologists:  APHI hosted the foremost international meeting of veterinary epidemiologists in 2000 (International Society for Veterinary Epidemiology and Economics, ISVEE) in Breckenridge, CO.  There were approximately 600 participants from 58 countries in attendance.

• TSE in Animal Populations Conference:  APHI hosted this September 2003 conference in Fort Collins, CO, which was sponsored by the Canadian Food Inspection Agency, International forum for TSE and Food Safety, Office International des Epizooties, and the US Department of Agriculture: APHIS.

• Continuing Education:  Continuing education lectures and scientific abstracts on biosecurity, antimicrobial resistance and food safety have been presented around the US and at international veterinary conferences by faculty and graduate students affiliated with APHI.