Emerging Animal Diseases: Global Markets, Global Safety: Workshop Summary (2002)

Several speakers addressed the importance of developing new methods of testing that would enable technicians to quickly and accurately detect the presence of pathogens in blood and tissue samples and also to distinguish between animals that are infected and those that have been vaccinated. The polymerase chain reaction (PCR) technique, which is still being developed and refined for various applications, figured prominently in the discussions. PCR is a technique of molecular genetics in which DNA is replicated and amplified, thus enabling genetic analysis and identification.

Caird Rexroad said the Agricultural Research Service (ARS) is focusing much of its current research efforts on PCR and other nucleic acid-based detection systems. Using PCR, one can “in a matter of less than an hour or two see the presence of foot-and-mouth virus in the samples.” The ARS is in the process of validating this method by conducting field tests, he said, noting that PCR tests can be used in the field in the case of outbreaks, as well as onsite at ports of entry.

Similarly, Quentin Tonelli highlighted the positive features of PCR and associated techniques. “Real-time PCR offers high sensitivity, and, more important than that, you have eliminated the need to culture the organism and,

hence, it is not biohazardous.” Additional benefits include the ability to test samples at dispersed sites and to run multiple samples by using automation.

Dr. Bruce Akey, Chief of the Office of Laboratory Services, Virginia Department of Agriculture and Consumer Services, noted that PCR is one important answer to the need for quick, accurate, and affordable diagnostic tests. Rapid or real-time PCR diagnostics are already being validated at USDA’s Plum Island Animal Disease Center for doing foreign animal disease work, he said.

Akey addressed the need for accurate tests. “It is not good having a fast test, or even a cheap test, if the results don’t tell you anything.” Tests should be validated to international standards (i.e., OIE standards), yet many of the tests, especially molecular diagnostics, that have been developed in-house in state and university labs have never been subjected to such validation, he said. The related issue of standardization of protocols is also critical, he said.

Rexroad addressed the need for new vaccines “that we could produce in this country, that don’t entail the use of a live virus, perhaps peptide vaccines or something that is based on DNA.” Other priorities for research include vaccines that (1) can quickly induce an immune state and prevent a carrier state, (2) have a long-lasting immune response, (3) can be produced in large quantities to meet demand in the event of an outbreak, and (4) are affordable. He said the ARS is working on viral-vectored foot-and-mouth disease (FMD) vaccines and is in the process of testing peptide vaccines.

Genomics plays a strong role in the development of new vaccines “in terms of understanding the immune response of the animal to a particular immunogen, but also how you can make a practical vaccine,” he said. Rexroad noted that genomics is now a focus of research at the Plum Island facility, where “genomics is playing a major role in terms of trying to understand the organisms, [and in] identifying the organisms that are likely to have a role in the emergence of new diseases in this country.”

Akey also stressed the importance of confidentiality in the handling of samples and test results, noting that producers are often reluctant to participate, fearing that they may face negative publicity or liability for a pathogen that is later traced back to their operation. Each state has its own Freedom of Information Act (FOIA) requirements, and, in Virginia’s case, labs are completely open to FOIA requests. “That scares off producers who don’t want to bring something into the state laboratory if they have a suspicion that it might

be something they wouldn’t want to see in the media or that, down the road, some disgruntled buyer of their product could come back and get their entire history of testing results from those laboratories.” One way to deal with this problem, he said, is for states to amend their regulations to give state veterinarians discretionary authority in FOIA decisions, rather than going after exemptions to the statute which “generally, in most states, is political suicide.”

Akey made a case for more collaboration between the federal government and the states in the area of research and for more federal support for the transfer of new technologies to state veterinary diagnostic laboratories. States are not asked for input in determining research priorities of the USDA’s Agricultural Research Service, and, as a result, state diagnosticians are unaware of much of the publicly funded research taking place at the ARS and in universities. “We don’t often find out until that technology has been leased to a private company,” at which point exclusive licensing agreements and high royalty payments often present insurmountable barriers to acquisition by the state. Having the latest diagnostic technologies available in a single laboratory does not provide adequate protection in an epidemic, when a large number of tests would have to be processed, he said. Brown added, “There is tremendous scientific and technical expertise in our state laboratories that is crying to participate in test development and validation. More federal partnering with state laboratories could provide tremendous synergy.” In addition to new diagnostic technologies, states also need funding and support to upgrade their physical facilities and hire additional staff with specialized training in molecular biology, epidemiology, and quality assurance, Akey said.

A National Animal Health Laboratory Network (NAHLN), similar to the Laboratory Response Network sponsored by CDC for public health, would also be useful to provide early detection and response to bioterrorism, emerging diseases, and emergency disease situations. The NAHLN would ensure that each state’s veterinary diagnostic laboratory had the equipment and expertise needed, performed testing according to standardized protocols, and were part of a secure, rapid-response communications network.

Weber of the National Cattlemen’s Beef Association also addressed the need for additional federal funding of programs that support animal health and food safety. Weber reviewed recent budgets for the USDA and pointed out that funding for the ARS and for the Animal and Plant Health Inspection Agency (APHIS), which he described as the agencies responsible for providing a partnership framework between state animal health officials and industry, working together to prevent the introduction of foreign animal diseases and to

work to eradicate those that we have, is far down on the list of budget outlays. He noted that over the last several years there has been a net loss in funding for such programs, resulting in a loss of intellectual and human capital for the industry and the veterinary medical infrastructure. “This is our greatest threat to the health of our cattle and livestock herds in the United States,” he said.

Weber stressed the need for a strong infrastructure at the local, state, and federal levels to prevent foreign animal diseases such as BSE (bovine spongiform encephalopathy) and FMD from occurring in the United States. There are about 100 million head of cattle in the United States, and the risks to industry of such an outbreak would be unacceptable, he said. “Obviously, we believe that the most significant allocation of resources has to be on prevention in the first place. The old saying is ‘an ounce of prevention is worth a pound of cure,’ and so we are extremely aggressive in asking government to protect our borders.”

Industry could be a very important partner to government agencies and labs in the case of an outbreak or terrorist attack, said Tonelli. Industry has the ability to develop and provide a large number of tests on fairly short notice, with standardized test formats to ensure consistent product performance, he said. Industry can also provide product training and technical support, he added. Tonelli suggested a number of strategies to enhance commercial development of diagnostics, particularly in emergency situations: (1) a mechanism for disease screening at regional sites, (2) creation of a special designation for screening positives that does not “confer any economic impact” until the test is confirmed, (3) establishment of a mechanism to drive consensus on what the test needs are, (4) quicker regulatory approval and/or permission to bring materials into the United States in special circumstances, (5) enhanced collaboration between government laboratories and industry worldwide, and (6) broader industry participation in emerging disease committees.