intro to parasitology

symbiosis

unlike organisms living together

commensalism

1 beniefits the other is neither helped nor harmed

example of commensalism

entamoeba coli in intestinal lumen

mutualism

a symbiotic relationship where both organisms benefit from each other.

example of mutualism

termits and flagellates in digestive systemthat aid in cellulose digestion.

parasitism

a symbiotic relationship where one organism benefits at the expense of the other.

example of parasitism

entamoeba histolyticacauses amoebic dysentery in humans.

endoparasite

a parasite that lives inside the host's body.

ectoparasite

a parasite that lives on the surface of a host, feeding on its body or fluids.

erratic

parasite found in an organ not its usual habitat

obligate parasite

a parasite that cannot complete its life cycle without spending at least some part of its life in a host.

facultative parasite

a parasite that can live both on a host and independently.

accidental parasite

a parasite that enters a host where it does not normally establish itself, often causing disease.

permanent parasite

a parasite that lives in or on a host for the entirety of its life cycle, relying on the host for survival.

temporary parasite

lives in host for a short period of tmesp

spurious parasite

a parasite that passes through a host without infecting

types of hosts

definitive

intermediatehost, paratenic host

definitive/ finals host

a host in which a parasite reaches maturity and, often, reproduces.

intermediate host

a host that harbors the parasite during its larval or juvenile stages before it reaches maturity in the definitive host.

paratenic host

a host that holds the parasite without allowing it to undergo any development, serving as a transport host to the definitive host.

reservoir host

allows ife cycle and becomes additional human resource of infection

vectors

responsible for transmission

phoretic vector

a type of vector that physically carries a parasite from one host to another without supporting the parasite's life cycle.

biologic vector

a type of vector that supports the development or reproduction of the parasite within its body before transmission to a new host.

modes of transmission

oral, skin penetration, antropod bites, congenital transmission, transmammary, sexual transmission

epidemiology

study of pattern, distribution, and occurance of disease

intensity of infection/ worm burden

burden of infection related to number of worms per infected personm

morbidity

the occurrence of disease or illness in a population.

mortality

the incidence of death within a population.

deworming

use of antihelminthic drugs

disease eradication

permanent eradication

disease elimination

the reduction to zero of the incidence of a specific disease in a defined geographic area.

sporadic

occurs infrequently and irregualrl

endemic

a disease or condition regularly found among particular people or in a certain area.

epidemic

a widespread occurrence of an infectious disease in a community at a specific time.

pandemic

an outbreak of a disease that occurs over a wide geographic area and affects a large proportion of the population.

mechanisms of injury

enzymes

invasion and destruction of host tissue

deprivation of nutrients required for host survival.

factors that affect outcome of infection

genetic makeup of host

nutritional status of host

immunity of host

parasite to host interaction outcomes

failure to establish

parasite established and host eliminates

parasite established and host begins to overcome but not fully

parasite established host tries to eliminate and damages itself int he process

parsite established and kills host

host parasite interactions

physical barriers (1st line of defese)

innate immune response

acquired immune system

parasite evasion mechanism

resistance to infection

immune suppression

antigenic variation

host mimicry

intracellular sequestration

resistance to infection

survival of parasites upon entering blood and tissues

immune suppression

Parasites can reduce immune function of macrophages

antigenic variation

Trypanosoma brucei infection: variant surface glycoproteins (VSG)

host mimicry examples

Echinococcus granulosus larval stages carry blood group antigens

Schistosoma sp. Can acquire antigenic molecules from host

examples of oral transmission

Taenia solium, Taenia saginata, and Diphyllobothrium latum • Entamoeba histolytica and Giardia lamblia • Clonorchis, Opistorchis, and Haplorchis

skin penetration

hook worms schistosoma

Congenital Transmission

Toxoplasma gondii

Transmammary

Ancylostoma and Strongyloides

inhalation of airborne eggs

Enterobius vermicularis

sexual intercourse route

trichomonas vaginalis