Ascaris lumbricoides eggs
Diphyilobothrium latum ova
Enterobius vermicularis eggs
Enterobius vermicularis eggs (too)
Necator americanus adult (tail)
schistosoma japonicum eggs
schistosoma mansoni miracidiae
schistosoma mansoni primary sporocysts
Percentage of people infected by helminths
- 1. Ascaris (30%)
- 2. hook worms (21%)
- 3. enterobius (10%)
- 4. schistosome (6%)
- 5. tapeworms (3%)
- 6. flukes-liver, lung (1.5%)
- 7. trichinella (1%)
Name the three groups of parasitic helminths
- 1. trematodes (flukes)
- 2. cestodes (tapeworms)
- 3. nematodes (roundworms)
Scientific name, Disease, Location, Infectivity, Identification, and Treatment of Trematode Parasites
- 1. C. sinensis
- 2. Clonorchiasis (liver disease)
- 3. Japan, Korea, Taiwan, US (Southern Asian Immigrants)
- 4. ingestion of infected undercooked fish
- 5. eggs in feces
- 6. Praziquantel - increases the permeability of the membranes of parasite cells(paralysis); Albendazole - depletes their glycogen stores
Clonorchis sinensis (liver fluke) life cycles
- 1. Embryonated eggs passed in feces
- 2. eggs ingested by snail, go from miracidea to sporocysts to rediae to cercariae
- 3. free swimming cercariae encysts in the skin or freshwater fish
- 4. Metacercariae in flesh or skin of freshwater fish are ingested by human host
- 5. excyst in duodenum
- 6. adults in biliary duct
What is the streak plate method and why is it used?
Method of isolation that allows for the formation of individual colony forming units by reducing the number of bacterial cells with each streaked quadrant.
What is a pure culture and how is it obtained?
- a laboratory culture containing a single species of organism.
- A pure culture is usually derived from a mixed culture (one containing many species) by transferring a small sample into new, sterile growth medium in such a manner as to disperse the individual cells across the medium surface or by thinning the sample manyfold before inoculating the new medium.
What is aseptic technique?
refers to a procedure that is performed under sterile conditions.
What are the cultural characteristics of bacterial colonies?
how do you make a bacterial smear
A Slide that has had bacteria placed on it and that has been treated to cause the bacterial cells to adhere to the slide
Small drop of water scoop small amount of bacteria onto slide and spread in small cirular motionheat fix to adhere the slide
why is heat fixation used
To adhere the bacteria to the slide and to help sterilize the surrounding area of the slide
what is a hanging drop method and why is it used?
method where a drop of a culture is placed directly on a coverslip (there is a circular depressed area in the middle of the slide) allowing the drop of broth to hang in the space of the depression. This technique is useful for thick cells such as protozoans must be examined
Used to examine live organisms
what is Brownian motion
when nonmotile organisms exhibit a dancing or jiggling motion that does not result in traveling any distance this is a specific name for this motion
Why would you perform a simple stain
to be able to examine single cells through a microscope.
Used as general, all purpose stains.
Usually basic dye that will stain the cell membranes are negatively charged.
What are the morphologies of bacteria?
- 1. Cocci
- 2. Bacilli
- 3. Vibrios
- 4. Spirillum/Spirochetes
Steps of Gram Staining
- 1) Choose isolated colony
- 2) Place bacteria on slide in a circular motion
- 3) Heat fix for about 30 seconds
- 4)Place on staining tray
- 5) Flood surface with crystal violet
- 6) rinse with water
- 7) flood surface with iodine
- 8)Rinse with water
- 9)Flood with Alcohol
- 10) rinse with water
- 11) flood Safranin
- 12) rinse- blot slide read with oil immersion lens of microscope- look for gram - and gram +bacteria
steps to acid-fast staining
- Prepare smear. Heat fix.
- Add Kinyoun's carolfuchsin and stain for 5 min. Rinse with water.
- Flood slide with acid-alcohol for 3 min. Rinse with water.
- Add acid-alcohol for 1 min or until no more stain is removed from smear. Rinse with water.
- Counterstain with methylene blue for 1 min.
- Rinse slide with water and air-dry.
Schistosoma life cycle and route of infection
- 1. adult female lay eggs
- 2. eggs reach body of water after being excreted in feces or urine
- 3. eggs hatch into free-swimming larvae -> miracidium
- 4. miracidium penetrates snail
- 5. miracidium reproduces in snail, forming several cercariae
- 6. cercaria are released from snail
- 7. free swimming cercariae penetrate human skin, losing tail
- 8. cercariae travl through circulatory system to intestinal BVs where they mature into adults.
Tapeworms life cycle
- 1. adult female lay eggs in feces or urine
- 2. eggs hatch and release miracidia
- 3. miracidium penetrates snail
- 4. miracidium reproduces in snail -> sporocysts ->cercariae
- 5. cercaria are released from snail
- 6. free swimming cercariae penetrate human skin
- 7. cercariae lose tail during penetration, become schistosomulae
- 8. travel through circulatory system
- 9. migrate to portal blood in liver and mature into adults
- 10. paired audlt worms migrate to mesenteric venules of bowel/rectum (laying eggs that circulate to the liver and shed in stools) and to venous plexus of bladder
Necatur americanus life cycle
- 1. Eggs are passed in the stool, larvae hatch in 1 to 2 days. The released rhabditiform larvae grow in the feces and/or the soil
- 2. after 5 to 10 days they become filariform (third-stage) larvae that are infective .
- 3. On contact with the human host, the larvae penetrate the skin and are carried through the blood vessels to the heart and then to the lungs. They penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed .
- 4. The larvae reach the small intestine, where they reside and mature into adults. Adult worms live in the lumen of the small intestine, where they attach to the intestinal wall with resultant blood loss by the host .
- 5. Most adult worms are eliminated in 1 to 2 years, but the longevity may reach several years.
having both male and female organs in the sameindividual; hermaphroditic.
having the male and female organs in separate and distinct individuals; having separate sexes.
difference between cestodes, nematodes, and trematodes
the anterior, headlike segment of a tapeworm, having suckers,hooks, or the like, for attachment.
one of the segments or joints of a tapeworm, containing completereproductive systems, usually both male and female.