Protozoa

Question 1

What is a parasite

Answer 1

An organism that lives in or outside another organism(the host) and often harms it cuz the parasite finds on it for survival

Question 2

Parasites that cause diseases in humans are in three classes name them

Answer 2

Protozoans, helminths, Arthropods

Question 3

What is an ectoparasite, endoparasite, obligate and facultative parasite,accidental,intermediate ,reservoir and a definitive host and give examples

Answer 3

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

Question 4

Protozoan parasites are unicellular, eukaryotic organisms. Which kingdom are they from

Answer 4

Protoctista

Question 5

Most protozoan parasites are heterotrophic aerobes and are free. A few are pathogenic true or false

Answer 5

True

Question 6

Most protozoa are aerobes but which protozoa is an anaerobe

Answer 6

Intestinal Protozoa

Question 7

What is the route of transmission for intestinal, tissue and blood borne protozoa

Answer 7

1. Fecal-oral route I
2. Ingestion of undercooked meat
3. 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

Question 8

Name examples of Sarcodina, Ciliophora, Zoomastigophora, sporozoa and their locomotary structure

Answer 8

1. Entamoeba Coli, Entamoeba , gingivalis , E Histolytica : pseudopodia
2. Balantidium coli : Cilia
3. Giardia lamblia : Flagellate
4. Plasmodium species: uses apical complex to enter host cells but lacks locomotory strucutures

Question 9

E gingivalis infects where and how it it gotten

Answer 9

Infects the large intestine so it causes GI infections and infects the gum and is gotten by contact saliva or

Question 10

Entamoeba histolytica has three stages name them and what occurs at each stage

Answer 10

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.

Question 11

Explain the life cycle of E histolytica

Answer 11

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

Question 12

What diseases does E histolytica cause

Answer 12

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

Question 13

What are the complications of amoebic dysentery, diagnosis and treatment

Answer 13

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

Question 14

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

Answer 14

Balantidium coli

Question 15

What is the name for the ulcers causes by Balantidium coli

Answer 15

Balantidial dysentery

Question 16

What is the primary reservoir for Balantidium coli , diagnosis and treatment and life cycle

Answer 16

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

Question 17

Name the classes of zoomastigophora

Answer 17

Intestinal flagellates example Giardia Lamblia

Tissue and blood: Trypanosoma, leishmaniasis spp

Genitourinary: Trichomonas vaginalis

Question 18

What disease does Giardia lamblia cause and how does it cause disease and symptoms

Answer 18

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

Question 19

How does leishmaniasis occur and the types and where is it endemic at and what’s the diagnosis

Answer 19

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

Question 20

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

Answer 20

True

Question 21

Trypanosomiasis is caused by which species and name two forms of the species

Answer 21

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)

Question 22

Lifecycle of T brucei

Answer 22

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

Question 23

Example of blood borne sprozoa species

Answer 23

Plasmodium and babesia spp

Question 24

Types of plasmodium species and transmission and diagnosis

Answer 24

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

Question 25

Which plasmodium species when they go into the liver become dormant and after sometime resurface to cause relapse

Answer 25

Vivax and ovale

Question 26

Babesiosis looks like malaria but is transmitted by what

Answer 26

Ticks

Question 27

Toxoplasmosis is caused by which organism and has how many genotypes and what is the infective stages

Answer 27

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

Question 28

Difference between babesia and malaria in lab diagnosis

Answer 28

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.

Question 29

What are soil infecting helminths

Answer 29

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“),