PROCESSES AND PATHWAYS

Parasite

What is an organism that is dependent on another organism, deriving benefits from its host, which may or may not suffer consequences?

Host

What is the organism in or on which a parasite lives?

Endoparasites

What are parasites that live inside or within an organism?

Ectoparasites

What are parasites that live outside or on an organism?

Pathogenic parasites

What type of parasites cause direct harm to their host?

Commensals

What type of parasites do not directly cause harm to their host?

Obligate parasites

What type of parasites need a host at some stage in their life cycle to complete their development?

Facultative parasites

What type of parasites may live off of hosts or exist in a free-living form in the environment?

Accidental/Incidental parasites

What type of parasites are found in a host that is not normally its main host?

Zoonotic parasites

What are parasites that are mainly of other animals but can transfer to humans?

Spurious parasites

What type of parasites pass through the digestive tract without infecting the host?

Nematodes

What major parasite classification includes roundworms?

Cestodes

What major parasite classification includes tapeworms?

Trematodes

What major parasite classification includes flukes?

Protozoans

What major parasite classification includes "amoeba"?

Arthropods

What major parasite classification includes "insects"?

Flatworms

What is the common term for both Cestodes and Trematodes?

Segmented flatworms

What describes Cestodes in terms of their body structure?

Non-segmented flatworms

What describes Trematodes (flukes) in terms of their body structure?

Food-borne trematodes (FBTs)

What subclassification includes most trematodes, except for Schistosoma?

Definitive host

What type of host, also called the "final host," is where the parasite lives off its adult and sexual maturity stages?

Intermediate host

What type of host is where the parasite lives off its larval and asexual stages?

Paratenic host

What type of host is a carrier organism that harbors the infective stage of the parasite, but no further development occurs?

Reservoir host

What type of host is where the parasite continues any of its stages and acts as an additional source of human infection?

Vector

What is any organism responsible for transmitting parasitic infection from one host to another?

Mechanical vectors

What type of parasite vectors involve no development or changes in the parasite's life cycle stage during transit?

Biological vectors

What type of vectors transmit the parasite inside of them, where the parasite undergoes further development during transit?

Fomites

What are inanimate objects that can carry and spread disease and infectious agents?

Infective stage

What is the stage in the parasite's life cycle that enables it to infect humans?

Diagnostic stage

What is the stage in the parasite's life cycle that is usually identified to confirm the presence of a parasitic infection?

Egg/Ova

What is the most common infective stage of worms (helminthes)?

Embryonated egg/ova

What specific state of helminth eggs is usually the infective stage?

Larva

What is another common infective stage for some helminthes?

Rhabditiform

What is the feeding form of larvae?

Filariform

What is the aggressive form of larvae, often the infective stage for human helminth infections through skin?

Cercaria

What special kind of larvae infect humans, eventually becoming metacercaria?

Metacercaria

What is the infective stage developed from cercaria in flukes?

Cysts and Trophozoites

What forms do protozoans exist in during their infective stage, as they do not have ova/eggs or larva?

Oral route

What is a common mode of entry for parasites, especially via the fecal-oral route?

Fecal route

What is a common mode of exit for parasites, such as Ascaris?

Skin penetration

What mode of entry involves the parasite burrowing into the skin to reach the circulatory system?

Vector-borne

What mode of entry involves parasitic infection through a third party, like mosquitoes?

Respiratory (Inhalational/Direct Penetration)

What modes of entry involve inhaling infective stages or penetration of respiratory mucosa?

Blood transfusion/organ transplantation

What mode of entry involves receiving infected blood or organs?

Congenital transmission

What mode of entry is possible for some parasites, such as the motile form of Toxoplasma gondii crossing the placental barrier?

Autoinfection

What process occurs when a person already infected by a parasite is infected again by the mature offspring of the same parasite within their body?

Pruritus ani

What specific sign and symptom is characteristic of pinworms?

Prevalence

What epidemiologic measurement refers to the number of individuals infected per total population?

Cumulative prevalence

What epidemiologic measurement is the percentage of individuals in a population infected with at least one parasite?

Incidence

What epidemiologic measurement refers to new cases per total population?

Intensity

What epidemiologic measurement refers to the worm burden per individual, often quantified as eggs per gram of stool?

Selective treatment

What treatment strategy involves treating individuals?

Targeted treatment

What treatment strategy involves defining and treating at-risk groups?

Universal treatment (Mass Drug Administration or MDA)

What large-scale, population-based preventive chemotherapy involves administering deworming drugs regardless of infection status?

Elimination

What treatment goal involves reducing the rate of cases to zero for a specified parasite in a defined geographic area, requiring continued measures?

Eradication

What treatment goal involves the permanent reduction to zero of worldwide incidence of infection caused by parasites, with no continued measures needed afterward?

Kingdom Animalia

Which kingdom houses the more cellularly-complex worms and "insects"?

Kingdom Protozoa

Which kingdom houses the relatively simpler, unicellular parasites?

Complete digestive tract

What characteristic describes the digestive system of Nematodes?

Dioecious

What sex characteristic means Nematodes have distinct male and female worms?

Tegument

What metabolically active body covering do Cestodes possess instead of an internal digestive tract, which acts as a nutrient-absorbing organ?

Hermaphroditic/monoecious

What sex characteristic describes both Cestodes and Trematodes (with Schistosoma as an exception)?

Scolex

What is the prominent anterior portion of a Cestode?

Proglottids

What are the smaller segmented subunits of Cestodes?

Spatulate (with 2 grooves)

What describes the scolex of Pseudophyllidean cestodes?

Operculated

What describes the ovum of Pseudophyllidean cestodes?

Absent

What describes the uterine pore of Cyclophyllidean cestodes?

Highly branching

What describes the uterus of Cyclophyllidean cestodes?

Lateral

What describes the genital pore of Cyclophyllidean cestodes?

Bilateral symmetry, segmented body, jointed appendages, chitinous exoskeleton

What are the general characteristics of Phylum Arthropoda?

Cephalothorax, abdomen

What are the two body segments of Arachnids?

8 legs

How many legs do Arachnids typically have?

Chelicera

What is the mouth part of Arachnids?

Pseudopodium

What is the locomotory apparatus of Sarcodina (Amoebae), described as "false feet"?

Flagella

What is the locomotory apparatus of Mastigophora (Flagellates)?

Cilia

What is the locomotory apparatus of Ciliophora (Ciliates)?

Obligate intracellular parasites

What characteristic describes Phylum Apicomplexa in relation to host cells?

Apical complex

What collection of organelles and secretory structures do Apicomplexa possess to help them infect host cells?

Conoid

What feeding tube is present in the apical complex of Coccidia?

Without a conoid

What characteristic describes the apical complex of Hemosporidia, which explains why they invade cells to gather nutrients?

Protective response

What is the general nature of inflammation, designed to rid the body of cell injury causes and consequences?

Rapid (minutes to hours)

What is the onset time for acute inflammation?

Hours to a few days

What is the typical duration of acute inflammation?

Edema and emigration of neutrophils

What are the predominant characteristics of acute inflammation?

Neutrophils

What is the predominant inflammatory cell in acute inflammation?

Eliminating the offending agent

What is required to terminate the inflammatory response?

Chemical mediators breaking down, leukocytes having short lifespans, anti-inflammatory mechanisms activating

What are the reasons why acute inflammatory response resolves rapidly?

Regeneration of native parenchymal cells, filling the defect with fibrous tissue (scarring), or a combination of both

What are the processes by which injured tissue is replaced during repair (healing)?

Rubor (redness), Tumor (swelling), Calor (heat), Dolor (pain), Functio laesa (loss of function)

What are the five cardinal signs of inflammation?

Alterations in vascular caliber (increased blood flow/vasodilation), structural changes in microvasculature (increased permeability/leakiness), and emigration of leukocytes

What are the three major components of acute inflammation?

Infections and microbial toxins, tissue necrosis, foreign bodies, and immune reactions

What are the main stimuli for acute inflammation?

Toll-like receptors (TLRs)

What leukocyte receptors can detect bacteria, viruses, and fungi, triggering chemical mediators of inflammation?

Ischemia

What cause of tissue necrosis results from decreased blood flow, oxygen, and nutrient delivery due to arterial obstruction?

Hypoxia-inducible factor-1α (HIF-1α) protein

What protein mediates inflammation in response to hypoxia, activating genes involved in inflammation?

Exudation

What is the escape of fluid, proteins, and cells from the vascular system into the interstitial tissue or body cavities during inflammation?

High protein content, more cellular material, high specific gravity

What characterizes an exudate?

Increased permeability of blood vessels

What is the mechanism for the formation of an exudate?

Low protein content, little or no cellular material, low specific gravity

What characterizes a transudate?

Osmotic or hydrostatic imbalance across the vessel wall

What is the mechanism for the formation of a transudate?

Vasodilation

What is one of the earliest manifestations of acute inflammation, increasing blood flow and causing heat/redness?