Tasos Parasitic infections Flashcards
Give the definition of a parasite and the general problems they can cause?
- Organism living in or on another obtaining nourishment at the hosts expense
- Can cause malnourishment, illness and organ dysfunction for the host
Give the definition of a parasite and the general problems they can cause?
- Organism living in or on another obtaining nourishment at the hosts expense
What are endoparasites and ectoparasites?
Endoparasites - live in host
Ectoparasites - live on host
What is the life cycle of giardia intestinalis, what disease does it cause and what are the symptoms?
Belong to group Excavata (flagellated) - The protozoal cells, called trophozoites, produce a cyst - Cyst transmitted in water and food - Cyst become giardia in host - Giardia excreted in faeces > Causes Giardiasis > Symptoms: explosive, smelly diarrhea
What is the life cycle of giardia intestinalis, what disease does it cause and what are the symptoms?
- The protozoal cells, called trophozoites, produce a cyst
- Cyst transmitted in water and food
- Cyst become giardia in host
- Giardia excreted in faeces
> Causes Giardiasis
> Symptoms: explosive, smelly diarrhea
What are the 3 stages in the life cycle of Naegleria fowleri?
1) Cyst stage
2) Trophozoite stage
3) Flagellate stage (grows flagella)
What are the 2 types of trypanosomes and what do they cause?
> T.brucei - sleeping sickness - african trypanosomiasis
> T.cruzi - Chagas disease - American trypanosomiasis
What are the 2 types of trypanosomes and what do they cause?
> T.brucei - sleeping sickness - african trypanosomiasis
> T.cruzi - Chagas disease - American trypanosomiasis
What are the main 2 Plasmodia that can cause malaria in humans?
Plasmodium vivax
Plasmodium falciparum
(5 human infecting plasmodia total)
What are the symptoms of malaria?
- Fever up to 40oC
- followed by chills
- Prodromal syndrome: Head pain, photophobia, muscle pain and nausea
What are the symptoms of malaria?
- Fever up to 40oC
- followed by chills
- Vomiting and severe headaches
What is E. histolytica and what does it cause?
- found mostly in tropical and subtropical countries
- invasive
- Trophoziote stages live in the large intestine on mucosal surface
- These multiply by binary fission and produce cysts
- Cysts exit in stool, ingested in contaminated food or water
- Feed on body cells in small intestine, occcassionaly transported to liver
- Can cause diarrhea and liver abscess (2% adult patients)
What is E. histolytica and what does it cause?
- found mostly in tropical and subtropical countries
- invasive
- Trophoziote stages live in the large intestine on mucosal surface
- These multiply by binary fission and produce cysts
- Cysts exit in stool, ingested in contaminated food or water
- Feed on body cells in small intestine, occcassionaly transported to liver
- Can cause diarrhea and liver abscess
What is Cryptosporidium parvum and what is its life cycle?
- Single celled intracellular eukaryotic parasite
- Asexual and sexual phase
- Cysts in small intestine release sporozoites which invade epthelial cells
- Eventual merozoite production
- Sexual phase, oocytes released
- Contamination most commonly from ingestion water contaminated with oocytes
What is the major symptom of cryptosporidium infection?
Moderate or severe diarrhea
What is the definitive host and interdemiate hosts of Toxoplasma gondii? What does it cause and how?
Definitive host: Cat
Intermediate host: vertebrates including humans
Causes Toxoplasmaosis
- Lives intracellularly, forming large cysts
- Oocytes produced in cat faces
What 2 species of mosquito commonly transmit plasmodium in malaria?
Anopheles
Culex
How many people get malaria each year? How many die?
300 million human a year
2-3 million humans die
What is a complication of malaria that causes around 1/3 of malaria deaths?
Anemia
What are excavata and what are their structures?
Group of unicellular eukaryotes
Classified by flagellum
Have Ventral groove and 2 flagella
What are Fornicata?
Free living parasites
Belong to group Excavata
- No mitochondria, peroxisomes, primitive golgi
- ventral groove
What are the 2 main species within the phylum Euglenozoa?
Euglenoidea
Kinetoplastida
What are the properties of Euglenoidea and Kinetoplastida
Flagellates
Kinetoplastida contain kinetoplast (network of circular DNA called kDNA inside a mitochondria)
What is the structure of trypanosomes?
1st flagellum - free or undulating membrane
2nd flagellum - kinetosome only
In trypanosoma (genus affecting humans) they are small, thin and crescent shaped with one flagella
Cytoskeleton - complete microtubular corset
How does T.cruzi cause disease and what disease does it cause?
Development of the trypanosome into a trypomastigote in the blood and into an amastigote in tissues
- Causes Chagas Disease (American trypanosomiasis)
What are the 2 phases of Chagas Disease and what are the associated symptoms?
Stage 1 - Acute phase
- Lasts for around 2 months post infection
- Skin lesions or purple swelling of eye lids
- Can present with fever, headaches, swelling, muscle pain
Stage 2 - Chronic phase
- Parasites mainly in heart and digestive muscles
- 45% suffer with cardiomyopathy e.g arrythmias
- 11% megaesophagus
- 3% Megacolon
- Often fatal
What 2 types of T.brucei cause African sleeping sickness?
T.brucei gambiense - Chronic sleeping sickness
T.brucei rhodesiense - Acute sleeping sickness
What are the 4 phases of African sleeping sickness and what are the symptoms of each?
Stage 1 - local inflammation Stage 2 - swelling of lymph nodes (Winterbottoms sign) - splenomegaly - presence in blood > fever > anemia Stage 3 Passing through blood brain barrier - Neurological phase > confusion > Insomnia > Mania Stage 4 Progressive mental deterioration > Fatigue > Coma >Death
What disease do Leishmania (genus of trypanosomes) cause?
Leishmaniasis
What are the 3 clinical forms of leishmaniasis and what are the symptoms of each?
Cutaneous
- skin ulcers on face, arms and legs
Mucocutaneous
- Lesions can partially or totally destroy the mucous membranes of mouth, nose and throat
Visceral
- high fever, weight loss, swelling of spleen and liver and anemia
