Unit 2: Parasitism and Disease

Parasitism

An organism that obtains nutrients from one or a few host individuals, but does not usually cause death

Ectoperasite

On outside of the host.

Endoparasite

On inside of the host.

Relation ship between parasites and host?

Closely related hosts have closely related parasites.

Close Relationship Example

Lice and pocket golphers; lice stay on pocket golpher until host dies, lice die with host 

Vector

Organism that transmits the disease-causing agent (i.e. parasite)

Host

An organism that is required in the life cycle of the parasite but is not affected. The habitat

Intermediate Host 

An organism that is required in the life cycle of the parasite but is not affected. 

Reservoir

An organism with the parasite that is not affected or required in the parasite's life cycle.

Vector for Malaria

Mosquitos

Host for Malaria

Humans, frogs, birds

Reservoir for Lyme Disease

Deer; they show no symptoms.

Schistosomiasis

2-3 million cases per year, all over the world; hepatic and genital; must come into contact with water for long time; can’t withstand your stomach so enter through lesions on skin

3 Environments for Schistosomiasis

Humans—>Freshwater—>Snail ; best way to control is to control snail populations.

Bancroftian Filariasis Vector 

Mosquito 

Onchocerciasis (River Blindness) Vector

Black fly

Sleeping Sickness Vector

Tse-Tse fly; spreads through it’s saliva

Chagas Disease Vector 

Kissing bug; poops on you when it feeds 

Leishmaniasis Vector

Sandfly; little flies in bathrooms and around

Cutaneous Leishmaniasis

Skin lesions and burns/rashes