Submitted to: Veterinary Parasitology
Publication Type: Review Article
Publication Acceptance Date: 6/16/2007
Publication Date: 8/19/2007
Citation: Urban Jr, J.F., Steenhard, N.R., Solano-Aguilar, G.I., Dawson, H.D., Iweala, O.I., Nagler, C.R., Noland, G.S., Kumar, N., Anthony, R.M., Shea-Donohue, T., Weinstock, J., Gause, W.C. 2007. Infection with parasitic nematodes confounds vaccination efficacy. Veterinary Parasitology. 148(1):14-20.
Technical Abstract: The production of IL-12 and IFN-' resulting from exposure to many bacterial, viral, and protozoan pathogens is responsible for Th1-derived protective responses that also can inhibit development of Th2-cells expressing IL-4-dependent immunity to extra cellular helminth parasites and vice versa. In a similar manner, concurrent helminth infection alters optimal vaccine-induced responses in humans and livestock; however, the consequences of this condition have not been adequately studied especially in the context of a challenge infection following vaccination. Demands for new and effective vaccines to control chronic and emerging diseases, and the need for rapid deployment of vaccines for bio security concerns requires a systematic evaluation of confounding factors that limit vaccine efficacy. One common albeit overlooked confounder is the presence of gastrointestinal nematode parasites in populations of humans and livestock targeted for vaccination. This is particularly important in areas of the world were helminth infections are prevalent, but the interplay between parasites and emerging diseases that can be transmitted worldwide make this a global issue. This presentation will focus on recent vaccination studies in mice experimentally infected with Heligmosomoides polygyrus to model the condition of gastrointestinal parasite infestation in mammalian populations targeted for vaccination. In addition, a large animal vaccination and challenge model against Mycoplasma hyopneumonia in swine exposed to Ascaris suum will provide a specific example of the need for further work in this area, and for controlled field studies to assess the impact of other similar scenarios.