Immunodiagnosis of swine trichinellosis.

A rapid, sensitive and specific serologic test has been developed for the diagnosis of swine trichinellosis. The ELISA based test utilizes L1 stichosome antigens recovered as excretory-secretory (ES) products from in vitro cultivated muscle larvae. Field studies conducted with 20,000 commercial swine using crude ES antigen demonstrated that the test could detect 98% of the medically significant infections. The test had a false-positive rate of less than 3%. Because of difficulties in regulating the quality and quantity of ES antigen and the need to continually maintain infected laboratory animals for producing the diagnostic reagent, efforts have been made to clone and express the gene(s) encoding the immunodominant ES antigens. To date a cDNA sequence, designated TsA-12, which codes in part for a 53-kDa ES antigen, has been identified and expressed in bacteria. Results demonstrate that TsA-12 is recognized by immune sera and further suggest that the immunodominant 45-, 48- and 53-kDa ES proteins which share antigenic epitopes are distinct glycoproteins.

Economic losses resulting from food-borne parasitic zoonoses.

Economic losses resulting from food-borne parasitic zoonoses are difficult to assess. Estimating the global economic impact of these diseases is handicapped by inadequate information on the prevalence and public health importance of parasitic zoonoses for most countries. However, the economic losses caused by certain zoonoses has been estimated for some regions and in these instances the costs are significant. In Mexico, for example, porcine cysticercosis is responsible for a loss of more than one-half of the national investment in swine production and for more than US$17 million annually in hospitalization and treatment costs for humans with neurocysticercosis. For all of Latin America, porcine cysticercosis accounts for an economic loss of US$164 million. In Africa, losses of one to two billion dollars per year due to bovine cysticercosis have been reported. Human toxoplasmosis in the United States is estimated to be an annual economic/public health burden of more than US$400 million. The implication from these examples and other are discussed. A set of recommendations is presented for obtaining the necessary information needed to permit assigning to food-borne parasitic zoonoses their appropriate priority within each country's complex economic and public health problems.

Impact of biotechnology on trichinellosis control.

The century-old effort to rid Trichinella spiralis from the food supply has had variable success, and in some regions trichinellosis remains a serious public health concern. However, the research advanced during the past 5 years points toward greater success in developing practical and efficient control strategies. The application of monoclonal antibody and recombinant DNA technologies has permitted great improvement in diagnosis and production of diagnostic reagents. Further, the epidemiology of the disease has undergone considerable revision because of the power of DNA analytical technics which are unravelling the complex genetics of Trichinella spiralis. This improved understanding of the parasite's epidemiology is critical to the design of improved control strategies.

Application of biotechnology methods to the study of cestodes.

The advent of biotechnology has invigorated research on the control of cestode diseases, especially cysticercosis infections in man and animals. The utilization of hybridoma technology to produce antigen-specific monoclonal antibodies has resulted in great strides towards obtaining pure antigens relevant for immunodiagnostic purposes and for research on vaccines. However, the isolation and identification of antigens is only the initial step in the development of such reagents. Production of antigens in quantities sufficient for research/development and commercialization is hampered by the scarcity of viable parasite material for extraction. Expectations are that this problem can be surmounted by application of recombinant DNA methods to produce cloned genes for antigen expression in cultured microorganisms or cells. Remarkable progress has been made recently in isolating and cloning genes from several important cestode species and antigens have been expressed in vitro with genes cloned from Taenia taeniaformis and T. hydatigena. Although these early efforts have not as yet resulted in practical antigen production, the prospects for doing so appear good. The complex epidemiology of cestode diseases is another research subject that has benefited from the successful application of the tools of biotechnology. For example, the greater precision in typing biological variants afforded by DNA analysis has led to important revisions of the understanding of hydatid disease. DNA probes are now available for Echinococcus spp, which are effective for typing isolates. These probes may also find use as reagents for distinguishing eggs of Echinococcus from other taeniid eggs, a serious difficulty for field investigations.(ABSTRACT TRUNCATED AT 250 WORDS)