Toxicant-Disease-Environment Interactions Associated with Suppression of Immune System, Growth, and Reproduction

Abstract

The effects of marginal malnourishment , infections, and environmental chemicals on growth and reproductive success in Swiss-Webster white mice and wild deer mice were studied with fractional factorial designs. Interaction effects were discovered. For example, malnourished mice were more sensitive to virus exposure and environmental chemicals (a plant growth regulator or polychlorinated biphenyls). Since several commercial plant growth regulators also appear to suppress the immune system, these results cast doubt on the adequacy of current toxicity testing procedures in which factors are studied individually and not in combination.

Life Histories, Salinity Zones, and Sublethal Contributions of Contaminants to Pelagic Fish Declines Illustrated with a Case Study of San Francisco Estuary, California, USA

“…The desire to generate legal criteria that address contaminants in isolation from confounding factors has led to reliance on standardized laboratory tests with limited environmental reality (Heugens et al 2001). However, ecological effects of single or multiple contaminants, like the influences of weather, disease, food shortage, or behavioral disturbance, are more commonly sublethal contributors to a suite of adverse ecological conditions (Porter et al 1984). Moreover, exposure to contaminants along with other stressors is often highly episodic, as after major storms or during blooms of toxic cyanobacteria.…”

Cellular immune responses of nutritionally stressed juvenile cotton rats (Sigmodon hispidus) during acute benzene exposure

“…Wild populations of animals routinely encounter temporal shifts in the nutritional quality of their habitat, which can lead to malnutrition and eventually alterations in immunocompetence (Chandra and Newbeme 1977) and xenobiotic metabolism (Kalamegham et al 1981). Although much information exists on the sensitivity of the immune system to nutritional and chemical stress, less work has been done to explore possible interactions between these two stressors on immunocompetence (Kalamegham et al 1981;Porter et al 1984;Omaye 1986). …”

“…The immune system is an interactive and dynamic network of cells and soluble mediators which are sensitive to intrinsic and extrinsic stressors such as age, sex, reproductive condition, nutrition, and chemical stress (Lahita 1984;Dean et al 1986). Adequately assessing the potential hazards of environmental contaminants in wildlife populations will eventually require a clear understanding of possible interactions between normally encountered stressors and xenobiotics (Porter et al 1984). Wild populations of animals routinely encounter temporal shifts in the nutritional quality of their habitat, which can lead to malnutrition and eventually alterations in immunocompetence (Chandra and Newbeme 1977) and xenobiotic metabolism (Kalamegham et al 1981).…”

Tinkering with the Tinkerer: Pollution versus Evolution

“…PCBs and some herbicides may interact with infections to produce substantial effects on mortality and reproduction in natural populations of small mammals when food or water is limited (73). Captive harbor seals (Phoca vitulina) fed fish from the polluted waters of the Baltic Sea developed impaired T-cell mediated immune function accompanied by suggestions of increased bacterial infection (74).…”