Into to Parasitology Flashcards
How can parasites camouflage?
they are able to shuffle their surface proteins rapidly thereby escaping recognition by the immune system
How can parasites sabotage?
subvert host response
what major diseases are mosquito born?
- malaria
- elepantiatis
What major disease is fly born?
river blindness
Parasitism?
- a way of life is which one species gains its livelihood at the expense of another
- weaker organism obtains food and shelter from another organism
problems faced by parasites? (life cycle)
- ability- to establish infection in humans
- latency- ability to remain quiescent
- repliction
- restriction- in an immunological intolerant host
what are problems that parasites cause for people in terms of communication about parasites?
- attitudes that worms are not the sort of things that refined people talk about
- apparent reluctance of media to disseminate such information
- fact that poor people are the ones most seriously affected
What is key in a successful parasite? example?
- successful parasites do not harm their host
- example: herpes
What are different relationships a parasite can have with the host?
- symbiosis- close relationship
- mutualism- both benefit, not all symbiosis are mutualistic
- commensalism- one benefits, the other is not affected
Trypanosoma?
- ultimate master of disguise
- lives in blood stream and replaces its coats of proteins every two weeks
- greek trypano- auger, drill
- soma (body)- corkscrew like motion
About how many people in the world have intestinal round worms? malaria?
- worms: 1.4 billion
- malaria: 300 million
Protozoa?
- single cell
- lowest form on animal life, need microscope to see
- exist as cyst (infective stage)
- also exist as trophozoites (metabolically active stage)
Helminths?
- multicellular
- most are visible
- cause of chronic infections
- complex genome
- have multiple developmental stages
- conservation of sequences
- use of host derived cells for sequestration
- antigen masking
- antigen variation
What is Giardia lamblia (intestinalis)?
- protozoa
- cyst (infective) or trophozoites (metabolically active)
- patients with acute diarrhea pass trophozoites in stool (which are fragile, don’t survive in environment)
- cyst form- stay viable through water, desiccation, outside of body
What are some common helminths?
- nematodes- round worms
- platyhelminths- flat worms
- cestodes- tape worms
- trematodes- flukes
What are some soil dwelling nematodes/eggs?
- ascarias lumbricoides- round worms
- trichurias trichuria- whip worm
- ancylostoma duodenal- hook worm
What can we learn from the “sun king”?
-diet of rare meat was favored by nobility which contributed to parasitosis
pathogenicity of helminths?
- mechanical
- invasion and destruction of host cells
- inflammation
- competition for host nutrients
- worm burden
Charcot leyden crystals?
- the by product of eosinophil break down
- can be seen in sputum (ascariasis), stool (trichuriasis), urine, and CSF (angiostrongylus)
- they are dipyramidal and hexagonal
- usually evident with eosinophil breakdown and tissue damage from tissue invading parasites
Eosinophilia?
-generally caused by a helminth penetrating the mucous membrane during migration
Transmission of parasites?
- person to person (amebiasis)
- food borne (cyclospora)
- infected pets, farm animals, lab animals (cryptosporidium) -contaminated water (Giardia)
- sexual practices (Giardia)
- fecally contaminated fomites (cryptosporidium)
- contact with diaper age children (Giardia)
What is the F diagram? (22)
- shows the different fecal-oral transmission routes
- also shows possible barriers to prevent excreta related pathogens from finding a new host
What are barriers in specimen collection?
- perceived low occurrence of disease
- lack of familiarity with the disease
- lack of effective Rx
- expensive testing
- poor patient compliance with stool
- collection
Stool for O and P?
- should be repeated for better yield
- should be collected in closed containers
- urine and water may destroy the trophozoites
- reduced sensitivity due to interfering substances
What is the first test that can simultaneously detect 11 common viral bacterial and parasitic causes of infectious gastroenteritis from a single patient sample?
the xTAG Gastrointestinal Pathogen Panel (GPP)
What is the xTAG Gastrointestinal Pathogen Panel (GPP)?
- multiplexed nucleic acid test that detects 7 bacterial causes of gastroenteritis
- also detects 2 viruses, 2 parasites which are also common for gastroenteritis -all with one patient sample
How is there recognition of an outbreak?
- wide spread absenteeism among employees
- increased number of ER visits for diarrhea
- city wide shortage of anti-dirrheals
Delusory Parasitoses?
- patients think they have a parasite
- must seek psychiatric help Self Rx consists of:
- bathing in kerosene, mayonnaise, vinegar, bleach
- moving out of home
- picking, tweezing, cutting, poking
- shaving all of body hair
- burning skin with lighters
How do you control infection?
- proper hand washing and personal hygiene
- thorough washing/scrubbing of fruits/veggies
- proper waste disposal
- safe water supply
- thorough cooking of food
- prohibition of untreated night soil as fertilizer
- food stuff should not be harvested from pastures where animals graze
- improving domestic and personal hygiene
- controlling zoonotic reservoirs and water supplies
Hygeia?
neglected stepchild