Protozoa Flashcards
What is a parasite
An organism that lives in or outside another organism(the host) and often harms it cuz the parasite finds on it for survival
Parasites that cause diseases in humans are in three classes name them
Protozoans, helminths, Arthropods
What is an ectoparasite, endoparasite, obligate and facultative parasite,accidental,intermediate ,reservoir and a definitive host and give examples
An ectoparasite is one that lives on the outside of the host. Example: ticks
Endo: lives inside the body of the host. Example: tapeworm
Obligate: parasite that needs the host to complete its life cycle and completely depends on the host. Example: Toxoplasma
Facultative: can be in the external environment and undergo their life cycle without the host when conditions are favorable. Example : strongyloid stercolaris
Accidental: live in or on a host other than it’s normal host . Example: liver fluke is in sheep but cuz humans take care of sheep if it’s infected, it can get into the human
Intermediate: parasite develops in the host but doesn’t get to maturity. Example crab,black fly, female anopheles mosquito
Definitive: parasite reaches sexual maturity
Reservoir: is the source of infection and potential reinfection example HIV infected person
Protozoan parasites are unicellular, eukaryotic organisms. Which kingdom are they from
Protoctista
Most protozoan parasites are heterotrophic aerobes and are free. A few are pathogenic true or false
True
Most protozoa are aerobes but which protozoa is an anaerobe
Intestinal Protozoa
What is the route of transmission for intestinal, tissue and blood borne protozoa
- Fecal-oral route I
- Ingestion of undercooked meat
- They live in the blood and you get them by the bite of an arthropod vector eg female anopheles mosquito but can be transmitted by blood transfusion
Name examples of Sarcodina, Ciliophora, Zoomastigophora, sporozoa and their locomotary structure
- Entamoeba Coli, Entamoeba , gingivalis , E Histolytica : pseudopodia
- Balantidium coli : Cilia
- Giardia lamblia : Flagellate
- Plasmodium species: uses apical complex to enter host cells but lacks locomotory strucutures
E gingivalis infects where and how it it gotten
Infects the large intestine so it causes GI infections and infects the gum and is gotten by contact saliva or
Entamoeba histolytica has three stages name them and what occurs at each stage
Trophozite stage: is the feeding stage and the stage where pathologies are seen (clinical signs and symptoms) and has food vacoules that contain RBCs
Precyst stage: when trophozite a develop they turn into precyst and comes out of the tissue and into the lumen. It is non motile and non feeding with no cell wall or hyaline cyst wall
Cyst stage: it enters the lumen and is non feeding and is covered by a hyaline cyst and it is the infectious stage.
Explain the life cycle of E histolytica
Ingestion of cysts in fecaly contaminated food and water. Cysts survive the acid and alkaline environment of the stomach and small intestine respectively and undergoes excystation or cyst wall ruptured into trophozoites
The trophozoites migrate to the large intestine and invades the mucosal membrane with the help of protease and Feeds on epithelial cells causing ulcer and helping it multiply by binary fission.
When the TZs mature they forms precyst which turn into cysts and are excreted into the feces to the externa environment
What diseases does E histolytica cause
Amoebiasis or amoebic dysentery characterized by dysentery( infection confined to the large intestine causing ulceration and mucous bloody stools and comes with fever pain, vomiting (treat w antibiotics )while diarrhea is confined to small intestine and causes watery stools and comes without vomiting, fever and pain and is self limiting), vomiting, intestinal lesions, cramps, malaise
What are the complications of amoebic dysentery, diagnosis and treatment
Extensive intestinal lesions affectin peristalsis and causing death due to intestinal perforation and peritonitis
Extra intestinal amoebiasis : when parasite penetrates submucosa, muscle layer and serosa layer and into circulation
When it is carried into the liver it causes hepatic amoebiasis
Diagnosis: wet mount microscopy(sample is stool), serology
Treatment: metronidazole and if peritonitis ,surgery
What is the largest intestinal protozoa, stays mainly in the cecal region of the large intestine , occasionally at the end of the ileum and dwells in the lumen but can penetrate the layers and cause ulcers
Balantidium coli
What is the name for the ulcers causes by Balantidium coli
Balantidial dysentery
What is the primary reservoir for Balantidium coli , diagnosis and treatment and life cycle
Pig
Diagnosis and treatment is the same as for Amoebic dysentery
Has two stages instead of three for life cycle but is the same as that of E histolytica
Name the classes of zoomastigophora
Intestinal flagellates example Giardia Lamblia
Tissue and blood: Trypanosoma, leishmaniasis spp
Genitourinary: Trichomonas vaginalis
What disease does Giardia lamblia cause and how does it cause disease and symptoms
Giardiasis
Stages: trophozoites and cysts
Trophozoites have discs for attachment and 4 pairs of flagella or 8 flagella with two nuclei and live in the small intestine lumen, duodenum, jejunum
Cyst
Ingested cysts excyst to form TZs in the small intestine. May live freely or attached to the mucosa of the lumen by the discs and multiply. They form cysts and get into the stools
Symptoms: bloating,belching,diarrhea,flatulence
How does leishmaniasis occur and the types and where is it endemic at and what’s the diagnosis
Bite by sandflies
Extra cellular promastigotes are found in the gut of the sandfly and is the infective stage
I’m humans it exists as obligate intracellular amastigotes in the macrophages of humans.
Is endemic in volta region
Types: Visceral L: endemic in India and symptoms- abdominal swelling
Cutaneous L- causes disfigurement due to ulceration
Mucocutaneous L
Diagnosis - visceral ( amastigotes in the blood,lymph, tissues, spleen)
Cutaneous and mucocutaneous- amastigotes in the tissues
Serology
PCR
Trichomonas vaginalis has only trophozoites stage and causes degeneration of the vaginal epithelium followed by leukocytic infiltration due to intense inflammation of the vaginal epithelium accompanied by itching and discharge of leucorrhoea true or false
True
Trypanosomiasis is caused by which species and name two forms of the species
Trypanosoma brucei spp and spend parts of their life cycle in the gut of the tsetse fly
Forms of T brucei: T b gambiense: causes chronic form of trypanosomiasis (western and central Africa)
T b rhodesiense: causes acute form of infections (central and east Africa)
Lifecycle of T brucei
Trypomastigotes: found in mammalian host as bloodstream trypomastigotes and in the fly as procyclic trypomastigotes
Epimastigotes: found in the insect vector
Feeding tsetse fly injects metacylic trypomastigotes in the human . Injected trypomastigotes transform to become blood trypomastigotes which then multiply in the blood and lymph and are carried to other parts of the body notably the CNs . The trypomastigotes which remain in the blood at sucked up along w blood meal by a feeding Tsetse fly or Glossina spp. Blood stream trypomastigotes transform to procylic trypomastigotes in the midgut of the insect vector and multiply by binary fission
These then leave the midgut to the foregut and to the oesophagus,pharynx,hypopharynx and to the salivary gland where they transform into epimastigotes. After several asexual generations they transform into metacyclic trypomastigotes which is the infective stage
Example of blood borne sprozoa species
Plasmodium and babesia spp
Types of plasmodium species and transmission and diagnosis
P falciparum- causes cerebral malaria and is problematic cuz it develops resistance to many drugs
Vivax- some Africans are resistant cus they don’t have red cell receptors that the parasite can use to enter
Malariae
Ovale
Knowlesi
Make anopheles mosquito feeds on nectar but females feed on blood, blood transfusion and congenital infections
The infective stage for humans are the sporozoites and for mosquito is the gametocytes
Sp in mosquitoes go into humans after a bite and move thru the sling into the blood vessels and into circulation
It enters the liver(hepatic stage) and undergoes asexual reproduction and forms schizonts and is made up of many merozoites
Hepatocytes rupture to release the merozoites and these go and infects RBcs and it is when the RBCs are destroyed that symptoms starts to show.
In the RBCs the merozoites look like trophozoites and multiply rapidly ,rupture the RBCs that contain em and infect other RBCs. This continues till some
Merozoites transform into male and female gametocytes which are picked up together with blood meal by malaria vector
Diagnosis is by parasitological test using microscopy and commercial rapid tests
Which plasmodium species when they go into the liver become dormant and after sometime resurface to cause relapse
Vivax and ovale
Babesiosis looks like malaria but is transmitted by what
Ticks
Toxoplasmosis is caused by which organism and has how many genotypes and what is the infective stages
Toxoplasma gondii
231genotypes
Has two hosts- definitive (cats)and intermediate (humans,birds,etc) Oocysts (sporozoites)in definitive host Tachyzoites in the blood Tissue cysts(Bradyzoites )
Diagnosis-serology
Difference between babesia and malaria in lab diagnosis
Examination of thick and thin blood smears is useful in the diagnosis of these two diseases. While both organisms have a very similar sized lifecycle forms which selectively infect red blood cells and prompt hemolysis, there are a few useful distinguishing characteristics. In the case of babesiosis, which is transmitted by the Ixodes scapularis tick in the United States, there are small ring like structures, both within red blood cells and extra-cellularly. The diagnostic tetrad form, known as a Maltese Cross, is helpful if identified but is not frequently observed in human infections. No advanced forms or pigment is present. In the case of malaria, which is transmitted via the female anopheline mosquito, protozoa are only found within red blood cells and advanced forms, including schizonts or gametocytes, are helpful in further speciation, if present. Other features, such as size of the infected red cell, number of merozoites, level of parasitemia and gametocyte shape, are helpful in the morphologic assessment of the Plasmodium spp.
What are soil infecting helminths
Soil-transmitted helminths refer to the intestinal worms infecting humans that are transmitted through contaminated soil (“helminth” means parasitic worm): Ascaris lumbricoides (sometimes called just “Ascaris“),
