unit 3 - parasitic specialization

enteroparasites

what types of parasites develop attachment organs for attachment in the digestive tract?

suckers, hooks, teeth

what type of morphological adaptations can enteroparasites have to help them attach to the digestive tract?

attachment to the digestive tract- theses are enteroparasites

what are these morphological adaptations used for?

legs with prehensile elements (ex- claw, tarsal nail, etc)

what morphological adaptation do ectoparasites (such as lice) have in order to attach to the host?

attachment to the host- these are ectoparasites

what are these morphological adaptations for?

1. wing loss

2. no movement in intracellular stages

what 2 types of reduction of locomotive organs do we observe in parasites?

loss of wings

what is the morphologic adaptation in this parasite?

flagella/tail

leishmania lose their ______ when they are inside of the lymphocyte

they can now absorb nutrients from the host, so there is not need for the GI tract. instead, they replace their digestive organs with sexual organs, which are more beneficial because they can reproduce more easily

what might be the benefit of cestodes (ex- tapeworms) losing their digestive tract?

they have adapted a long, thin morphology in order to fit well in the intestines

how have enteric parasites adapted to their environment?

a long, thin morphology of the enteroparasites so they can fit better in the intestines

what is the morphological adaptation we see here?

they are more spherical

how have parasites of cavities adapted morphologically to their environment?

1. storage of spermatazoa

2. avoiding fertilization

3. hermaphroditism

4. increased genital organs

5. increased prolificacy/ resistance of the eggs

6. multiplication of asexual stages

what 6 reproductive adaptations do we see in some parasites?

spermatheca

some parasites have a _______, which is a storage area for spermatazoa

releasing the ovum before fertilization in order to avoid reproduction asexual replication from unfertilized egg

some parasites perform parthenogenesis. what is this?

they do not need to search for a mate and can reproduce quicker

why is hermaphroditism advantageous?

trematodes

what class of parasites are almost always hermaphrodites?

cestodes and lernaeas

what 2 classes of parasites have great development of sexual organs?

it is a way to preserve themself because they can make "clones" in immature stages and increase their chances of survival

how is the multiplication of asexual stages in protozoa beneficial?

larval

cestodes perform asexual reproduction in their ____ stage

parasites adapt their life cycle/reproduction in accordance to the season

what is seasonal convergence?

seasonal convergence

haemoproteus lives in the blood of birds. at certain times of the year, there is an increase in the parasites in the adult birds because they are preparing themselves to infect a new group of potential hosts- this occurs in the spring because this is when the new chicks are hatching. what type of adaptation is this called?

timely convergence

dirotilaria immitis (heartworm) infect dogs, where they release their larva into the blood vessels, which are then carried throughout the circulatory system. to be transported to a new host, they need to be carried by a mosquito. in order to increase their chances of being taken by a mosquito, they go to the superficial blood vessels at dusk, when mosquitos are active. what is type of adaptation is this?

the delay in development/reproduction in response to dangerous environmental conditions

what does temporal arrested development mean (hypobiosis/diapause)?

temporal arrested development/ hypobiosis/ diapause

mosquitos have adapted to not reproduce during the winter because they do not survive very well in cold weather- what is this adaptation called?

enteroparasites

what types of parasites have adapted resistance to digestive enzymes?

1. resistance to digestive enzymes

2. adaptation to environments with poor oxygen

what are the 2 physicochemical adaptations that we see in certain parasites?

parasites in the same habitat develop similar strategies

ex- blood sucking parasites develop the same anticoagulant properties

what does convergent adaptation mean?

different species of parasites share the same host, so they must coexist

define polyparasitism

the situation when a parasite's host is another parasite

what is hyperparasitism?

1. large size- helminths and protozoa are usually larger than the immune cells so cannot be phagocytized

2. biological cycle complexity- parasites change location in the host depending on their cycle, making it difficult for immune cells to find

3. antigenic variation- confuses immune cells of host

what are the 3 different methods used by parasites to block the immune response of the host?

because it avoids phagocytization by host immune cells

why might it be beneficial for helminths and protozoa to be large in size?

cytokines

some parasites can produce _____ to mislead the host immune cells

they live inside of the host cells so cannot be phagocytized

how do leishmania avoid immune response in the host?

they have variable antigens, and sometimes the antigens change with the different stages of their life cycle

why is it hard to vaccinate against parasites?