Parasite load

In evolutionary biology, parasite load has important implications for sexual selection and the evolution of sex, as well as openness to experience.

[2] Differences in movement patterns, habitat choice, diet, body size, and ornamentation are all thought to contribute to this sex bias observed in parasite loads.

Whenever sexual dimorphism is exhibited in species, the larger sex is thought to tolerate higher parasite loads.

This is a common practice in veterinary medicine and is used to calculate parasite load in domestic animals, such as cats and dogs.

Hamilton and Zuk (1982) suggested that females of species could base their choice of mates on heritable resistance to parasites.

For example, parasitologists at the Universidade de São Paulo researched the effect of Chaga's disease on the immune system.

They found that individuals who survived the acute phase of infection develop parasite-specific immune response that reduces parasite levels in tissues and blood.

[10] This research aims to discover if the parasite load during the acute stage of infection affects if the host will eventually have a positive immune response.

The research was conducted on mice, with the intention of eventually using the information gleaned from the experiments to assist humans who have contracted Chaga's disease.

Marinho et al. found that parasite loads in the acute phase of infection correlates at the late chronic stage of the disease, with the intensity of the activation and response of the immune system of the host.

Pulkkinen et al. also found that after a period of time there was a corresponding reduction in average size of crabs, and therefore the mortality rate due to malnutrition and environmental stress was reduced.