parasitology lecture 3: intro to parasitology & parasite diversity

what is a host?

any organism in which a parasite lives and may undergo development

definitive and intermediate hosts have some type of parasite development take place within them

what is a vector?

an organism (usually an arthropod) that serves as a medium to transmit a parasite from one host to another

note: biological vectors are also hosts-> parasites undergo some type of needed developmental change and/or replication in these vectors

why is understanding parasite diversity important?

allows us to understand how various groups of parasites have adapted to their hosts

- helps to predict how parasites may invade new hosts

- aids in treatment and control efforts

current systematics can assist in identification and classification of new parasites

what is a species?

a species is a group of individuals with similar properties allowing them to interbreed with one another, produce fertile offspring, and that do not regularly interbreed with other species

what is a dioecious species?

a species that is compromised of separate male and female individuals

what is a monoecious species?

a species that has functional reproductive organs of both sexes (hermaphroditic) and are capable of self-fertilization or cross-fertilization

the use of what has revolutionized our understanding of biodiversity?

metagenomics

it is uncertain how many species of parasites exist, especially when counting eukaryotes

what is taxonomy? what are the two models?

the science of identification, description, and naming of organisms

darwin's model (old) and modern models

what is interesting about archaea & parasitism?

many archaea are extremeophiles but it is clear that they are becoming more ubiquitous. some have even been found in the human microbiome.

adoption of parasitism appears rare for archaea. the only known parasitic archaea latches onto the surface of other microbes.

can bacteria be considered parasites?

yes!

of the 16 well-known bacterial lineages, how many contain human pathogens? what are the most common examples?

8; chlamydia, rickettsia, yersinia pestis (plague)

what is an example of a free living, yet parasitic, species?

spirochetes

what are stramenophiles?

- eukaryotic parasites

- many of them produce flagella of 2 different shapes in their motile phase

- members include organisms such as free-living species like diatoms, golden algae, and brown algae

- can also be parasitic species like water molds or oomycetes

what is the famous example of a stramenophile?

causative agent of blight, irish potato famine (phytophthora infestans, p.infestans)

what is the name of the stramenophile that colonizes over a billion people but is mainly asymptomatic?

blastocystis

what are aveolata?

- eukaryotic parasite

- include ciliates, dinoflagellates, and apicomplexa

example) oodinium-> the sparkly fish

what are rhizaria?

- eukaryotic parasites

- mostly unicellular, some produce pseudopods and some are spore-forming

- most are free-living but some are parasitic

example plant parasite) Phytomyxea-> causes clubroot on cauliflower. also know haplosporidium.