Threat of Foreign Arthropod-Borne Pathogens to Livestock in the United States

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln U.S. Department of Agriculture: Agricultural Publications from USDA-ARS / UNL Faculty Research Service, Lincoln, Nebraska 2002 Threat of Foreign Arthropod-Borne Pathogens to Livestock in the United States Ralph A. Bram University of Nebraska-Lincoln John E. George USDA-ARS Robert E. Reichard Office International des Epizooties Walter J. Tabachnick University of Florida Follow this and additional works at: https://digitalcommons.unl.edu/usdaarsfacpub Part of the Agricultural Science Commons Bram, Ralph A.; George, John E.; Reichard, Robert E.; and Tabachnick, Walter J., "Threat of Foreign Arthropod-Borne Pathogens to Livestock in the United States" (2002). Publications from USDA-ARS / UNL Faculty. 321. https://digitalcommons.unl.edu/usdaarsfacpub/321 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Publications from USDA-ARS / UNL Faculty by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. FORUM Threat of Foreign Arthropod-Borne Pathogens to Livestock in the United States 1 2 3 4 RALPH A. BRAM, JOHN E. GEORGE, ROBERT E. REICHARD, AND WALTER J. TABACHNICK J. Med. Entomol. 39(3): 405Ð416 (2002) ABSTRACT There are manyexotic animal pathogens throughout the world that, if introduced into the United States, could have a signiÞcant detrimental impact on the health of livestock, agricultural economy, the environment, and public health. Many of these pathogens are arthropod-borne and potential vectors are readilyavailable in the United States. A number of these arthropod-borne pathogens are discussed here as examples that illustrate the potential risk and the consequences of inadvertent introductions. Several International agencies have a role in global surveillance and in controlling animal diseases should theybegin to expand their range. The risk to the United States is considerable. We propose that the United States invest in the improved infrastructure needed to reduce the risk of foreign arthropod-borne pathogens. Current U.S. programs focus on the exclusion of pathogens through regulation of animal movements and products, surveillance, especiallytrained animal disease diagnosticians, research support, international cooperation and, should pathogens enter our country, the resources for their prompt eradication. We suggest that the United States needs to develop a comprehensive, updated strategic plan to assess all aspects of current and future require- ments, objectives, and resources needed to protect its national interests. KEY WORDS arthropod-borne pathogens, foreign animal disease introductions, disease eradication THERE ARE NUMEROUS exotic animal pathogens through- foreign diseases maybe zoonotic and, thereby,have out the world that, if introduced to the United States, serious public health consequences. Some foreign ar- could be catastrophic for the health of livestock, our thropod-borne pathogens disrupt the environment agricultural economy, the environment, and public through effects on wildlife. The purpose of this article health. Manyof these pathogens are arthropod-borne is to review the threat of foreign arthropod-borne and potential indigenous arthropod vectors are readily pathogens that affect livestock, their potential impact available to biologicallytransmit them to humans, do- on agriculture, public health, and the environment, mestic animals and wildlife in the United States. The and the need to strengthen measures to reduce their resulting diseases could cause major production losses impact. in livestock and livestock products, therebyreducing The survival, establishment, and spread of animal farm incomes and increasing costs for consumers. diseases depend on climate, geographic factors, host Some of the diseases mayinhibit trade in livestock and species and their distribution. In addition, human ef- livestock products between states or world markets, forts to prevent, control, and eradicate some animal causing major losses in export income. Livestock spe- diseases have played a role in their distribution. Unlike cies that are susceptible to foreign arthropod-borne human diseases, animal disease control can be greatly pathogens include cattle, swine, sheep, goats, and enhanced byrestricting the movement of animals and horses. In addition, manyspecies of wild animals may animal products both nationallyand internationally. also succumb to pathogens transmitted byarthropods. However, arthropod-borne animal pathogens pose These diseases maycause high mortalityand/or mor- even greater challenge. Effective management of the bidityresulting in chronic debilities such as reduced associated disease vectors is sometimes possible rates of reproduction, lowered meat and milk produc- through a program of vector control or eradication. tion, or general poor health. Other arthropod-borne However, using animal movement restrictions maybe inadequate to control an outbreak in the face of mo- 1 Midwest Livestock Insects Research Laboratory, USDAÐARS, bile arthropods. Universityof Nebraska, Lincoln, NE. Current address: 4760G Water Park Drive, Belcamp, MD 21017. Although expensive, it is generallymore economical 2 Knipling-Bushland U.S. Livestock Insects Research Laboratory, to eradicate epizootic animal diseases than to live, year USDAÐARS, 2700 Fredericksburg Road, Kerrville, TX 78028. after year, with the economic losses they impart. This 3 OfÞce International des Epizooties, Paris, France. Current ad- approach, although successful with some infectious dress: 3602 Las Colinas, Austin, TX 78731. 4 To whom reprint requests should be addressed: Florida Medical animal diseases, i.e., foot and mouth disease, hog chol- EntomologyLaboratory,Universityof Florida, 200 9th Street SE, Vero era, and viscerotrophic velogenic Newcastle disease, Beach, FL 32962 (e-mail: [email protected]ß.edu). is especiallydifÞcult with arthropod-borne animal 406 JOURNAL OF MEDICAL ENTOMOLOGY Vol. 39, no. 3 pathogens that have wildlife or vector ampliÞcation Several governmental and international agencies cycles that enable the pathogen to survive. The eco- have a role in preventing the introduction and spread nomic beneÞt of completelypreventing the entrance of animal diseases across political boundaries. Those of certain transmissible diseases into a countryusually most important to the United States are the U.S. De- far outweighs the costs of the control measures. Coun- partment of Agriculture (USDA) and OIE. Other in- tries devote considerable attention to preventing the ternational agencies having some responsibilityin the introduction of disease causing pathogens through prevention and control of animal diseases include the import restrictions that are one kind of nontariff trade Food and Agriculture Organization (FAO), the Inter- barrier. The United States, for example, suffered nine national Atomic EnergyAgency(IAE), and the World outbreaks of foot and mouth disease in the decades Health Organization (WHO) along with regional or- preceding 1930, after which importation of meat and ganizations such as the Pan American Health Orga- animals was prohibited from countries with the dis- nization and the International Institute for Coopera- ease. There have been no foot and mouth disease tion in Agriculture (IICA). outbreaks since that time. The U.S. VeterinaryServices (VS), part of USDAÕs Estimating costs of an exotic animal disease epizootic Animal and Plant Health Inspection Service (APHIS), in a countryis complex. It is made even more so bythe is charged with preventing the introduction and loss of animal exports when other countries close their spread of animal diseases in this country. The regula- borders to animals and products until the epizootic is tion of the importation of animals and animal products contained or eliminated. Because vaccination can to prevent the entrance of potentiallydevastating live- mask disease, restrictions on movement are frequently stock diseases has been increasinglycomplemented by maintained until vaccination against the pathogen is cooperation with neighboring countries and trading terminated. Export losses mayfar exceed those of partners to keep these diseases from U.S. borders. This production. Trade losses caused bythe presence of mutual cooperation began in 1947 when the USDA strictlyarthropod-borne animal diseases are normally started to assist Mexico to successfullyeradicate foot conÞned to that of live animals and germplasm. Coun- and mouth disease. There are also several arthropod- tries do not usuallyrestrict import of meat from geo- borne diseases such as Venezuelan equine encepha- graphic regions in which there are animals infected litis, African swine fever, and bovine babesiosis, for which cooperation has been established with other with arthropod-borne diseases if the pathogen is not countries. Although not considered an arthropod- known to be transmitted bymeat. Live animal trade, borne pathogen in the entomological sense, the erad- however, is also an immense international business, ication of the screwworm, Cochliomyia hominovorax with millions of head of livestock crossing borders (Coquerel), from North America, is a remarkable ex- worldwide each month. In this case, severe importa- ample of cooperation between neighboring countries tion restrictions maybe imposed to prevent disease to eliminate a major livestock

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