Abstract

Abstract. Public health laboratories are facing critical issues, not the least of which is the problem of accurate surveillance of all of the rabies virus variants throughout the U.S. and other countries. The Rabies Steering Committee, which met at the CDC in Atlanta in 1994, recognized the utility of antigenic and molecular typing of virus variants in rabies surveillance and suggested an expansion of typing capabilities. The successful collaborations between the CDC and the Texas rabies laboratory over the last 15 years* produced the typing data to identify rabies variants common to animal reservoirs in the southwestern U.S. and Mexico and mapped their geographic distribution. Appropriately used, this knowledge should allow those who survey rabies to recognize when established reservoirs enlarge or expand into new areas or when different animal species become involved in cycles of rabies virus transmission. Key elements in this type of disease surveillance are a broad based sample collection system and the ability to process a large number of samples in a timely fashion. Methods of sample collection and rabies diagnostic testing already exist through public health laboratories in all 50 states; however, few of these laboratories have the expertise or operating budget to extend their laboratory testing to virus typing. The rabies laboratory at the CDC types several hundred samples each year, but does not have the staff to characterize the thousands of rabies positive animals identified each year in state laboratories. It is in this latter area that regional laboratories can expand and complement the flow of national surveillance data by increasing their surveillance activities to include antigenic and molecular typing of virus samples from the surrounding states.

This presentation will describe historical perspectives of rabies virus typing; discuss the process of program implementation; illustrate examples of various identified rabies virus variants; and assess the benefits associated with a regional reference laboratory. It is critical that all of the states function and work together if we are to augment a more vigilant surveillance system and the Texas Department of Health is in the unique position to lead the way.

*Smith, J.S., et al. 1986. Demonstration of antigenic variation among rabies virus isolates by using monoclonal antibodies to nucleocapsid proteins. J. Clinical Micro. 24:573-580.

Smith, J.S., D.B. Fishbein, C.E. Rupprecht, and K. Clark. 1991. Unexplained rabies in three immigrants in the United States. A virologic investigation. N. Engl. J. Med. 324:205-211.

Clark, K.A.,, S.U. Neill, J.S. Smith, et al. 1994. Epizootic canine rabies transmitted by coyotes in south Texas. J. Am. Vet. Med. Assoc. 204:536-540.

Rohde R.E., S.U.Neill, K.A. Clark, and J.S. Smith. 1997. Molecular epidemiology of rabies epizootics in Texas. Clin Diagn Virol. 8:209-217.

Fearneyhough, M.G. , et al. 1998. Results of an oral rabies vaccination program for coyotes. J Am Vet Med Assoc. 212, No. 4: 498-502.

Rohde R.E. and C. Hodges. 1998. Healthy Texans: The Veterinary Perspective. Texas Veterinarian 60, No 2: p. 16.

Sabouraud, A., J.S. Smith, L.A. Orciari, C. de Mattos, C. de Mattos, and R.E. Rohde. 1999. Typing of rabies virus isolates by DNA enzyme immunoassay. J Clin Virol. 12: 9-19.