Chapter 14- Parasitism and Infectious Diseases

LT1: Many different types of parasites that affect the abundance of host species

Infection resistance- the ability of a host to prevent an infection from occurring.

Infection tolerance- the ability of a host to minimize the harm once an infection has occurred

Parasite Load- the number of parasites of a given species that an individual host can harbor

Ectoparasite- a parasite that lives on the outside of an organism

Endoparasite- a parasite that lived inside an organism

Common Ectoparasites- nematode, flea, louse, mite and tick

Endoparasites

• viruses

• prions

• helminths

Emerging infectious disease- a disease that is newly discovered or has been rare and then suddenly increases in occurrence.

LT2: Parasite and host dynamics are determined by the probability that the parasite can infect the host.

Horizontal transmission- parasite moves down between individuals other than parents and offspring.

Vector- another organism to disperse the parasite from one host to another; sometimes multiple host.

Vertical transmission- a parasite moved from a parent to its offspring

Reservoir Species- species that can carry a parasite but do not succumb to the disease that the parasite causes in other species

LT3: Parasite and host populations commonly fluctuate in regular cycles.

Susceptible-infected-resistant (S-I-R) model- the simplest model of infectious disease transmission that incorporates immunity

LT4: Parasites have evolved offensive strategies, while hosts have evolved defensive strategies

Host adaptions

• avoidance on infected feces, etc

• removal of ectoparasites

• anti-fungal, antibacterial chemicals

• chemical to deter herbivores