human and animal parasites 1

infection

entry and development of an infectious agent in the body

pathogen

an infectious agent capable of causing disease in a host

disease

pathological condition with symptoms that set it apart from normal body state

virulence

the ability of a parasite/infectious agent to reduce its host’s fitness

fitness

a measure of the success of an individual in passing on its genes to future generations and is influence by the organism’s ability to live to reproductive age.

phoresy

no tropic interaction: hitching a ride

commensalism

one partner benefits, no one is harmed: “eating at the same table”

mutualism

both partners benefit from the asssociation

exploitation

aka parasitism! unidirectional benefit with a disadvantage for the other partner

endoparasite

parasite that lives inside the host body

ectoparasite

parasite that lives outside or on the host body

microparasite

microscopic, more difficult to count directly

macroparasite

larger parasites, easy to count in a host

obligatory parasite

requires its host to complete its life cycle

faculatative parasite

free-living, but can become parasitic, given the opportunity

opportunistic parasite

takes advantage of a circumstance to infect a host that it doesn’t normally infect

hyperparasite

a parasite of a parasite

castrator

stops host reproductive activities (diverts resources to its own developent)

body snatcher

parasite that takes over the host

parasitoid/protelean parasite

parasitic juvenile, free-living as an adult

definitive host

host in which parasite achieves sexual maturity

intermediate host

host in which a parasite undergoes a required developmental step and may reproduce asexually, but not sexually

heteroxenous (indirect) life cycle

more than one host

direct/monoxenous life cycle

one host

paratenic/transport host

“Safe haven” in which a parasite can persist and prolong survival, increasing its likelihood of transmission to a new host- nonessential

reservoir host

an animal that harbors an infection that can be transmitted to a human

vector

a means my which a pathogen is transmitted

mechanical vector

picks up a pathogen and carries it to a new host (no development or replication of the pathogen occurs)

biological vector

multiplication or development of the pathogen occurs before transmission to the new host

cyclodevelopmental transmission

development of pathogen, but no transmission

propagative transmission

multiplication of pathogen, but no development

cyclopropagative transmission

development of at least one life cycle stage and multiplication

fecal-oral transmission

propagule released in feces and contaminates water or food

trophic transmission

parasite takes advantage of a predator-prey relationship between definitive and intermediate hosts (HOST CONSUMES INFECTED HOST)

direct penetration

parasites are motile and seek out their new host and burrow in (high energy cost, and must find new host quick!) (think duck rash)

periodicity

time emergence from previous host to coincide with best chances of encountering new host

vector transmission

kissing bugs/mosquitoes etc: athropod blood feeders, mechanical vector transmission

vector competence

some species of an organism are better than others at transmitting disease

vector capacity

other factors that influence the ability of a component vector to transmit a pathogen: regular feeding on the host, feeding for extended period of time, dispersal ability, abundacne

sexual transmission

transmission via sexual conduct (trich)

vertical transmission

transmission from mother to offspring (breastmilk/placenta) redwater fever due to babesia

fecundity

the number of offspring that are generated (platyhelminthes, tapeworms, and protozoans all release large #’s of eggs)

host range

how many hosts can the parasite infect

tropism

preference

ectoparasites

attach tp the external surface of a host

molecular signposts

precense of certain chemical signals to determine what organ theyre in

allee effect

in small populations, individual fitness increases as a population density increases

chemoattractants

chemical signals that draw parasites together

propagule

infectious agent responsible for transmission

apicoplast

plastid-like organelle, similar to chloroplast, but non photosynthetic, result of secondary endosymbiosis, separate genome that encodes for ribosomal components, important for lipid metabolism

primary endosymbiosis

mitochondria, chloroplast, kinetoplast

sequestration

parasites export protein to the surface of the RBS to make them sticky (coadherance and rosetting)

_________________ is a human zoonosis

P. knowlesi

food vaculoe

is where hemoglobin is degraded

micronemes

initial attachment and invasion

rhoptries

invasion and establishment of intracellular infection

immature oocysts

the propagule for a secondary infection in toxoplasma gondii

endodyogeny

daughter cells are built within the mother cell

cerebreal toxoplasmosis

brain lesions caused by replicating parasites

occular toxoplasmosis

lesions and scarring of the retina

congenital toxoplasmosis

primary infection during pregnancy

how is toxoplasma diagnosed?

PCR to measure parasite DNA in body fluids, for chronic measure IgG antibodies with ELISA or fluorescent microscopy

excystation

sporulation/activation

Cyclospora cayetanensis

relapse commonly occurs in…

90% of human cryptosporidium infections are caused by..

cryptosporidum parvum

mitosome

no mitochondrion: dependent on anaerobic respiration

crypto sporidium has a ____ life cycle

direct

Low cure rate

reduces parasite numbers rather than complete cure

kinetoplast

dense mass of DNA in maxicircles and minicircles

maxicircles

20-40 kb: encode mitochondrial genes

minicircles

0.5-10kb: guide RNAs used to decode the maxicircles RNA-editing

Fifth base in kinetoplastids

Base J: like a repressive mark

hemoflagellate

lives in circulatory system and tissue fluids, some invade cells

Why are treatments for parasites so difficult to develop?

Make to kill eukaryotes, US and parasites are eukaryotic

Xenodiagnosis

Uninfected bug feeds to see if becomes infected after

mechanical transmission

passive transfer from an organism that doesn’t play a role in the parasites life cycle

haematophagus

blood feeding

4 types of leishmeniasis

cutaneous- most common: papules/nodules to ulcers

mucocutaneous

asymptomatic

visceral- infection spreads to organs