5: Parasitic infections Flashcards
What is an infection?
invasion by and growth of
pathogenic microorganisms
within the body
What is a disease
Summarised: something malfunctioning in body due to many causes (including infection)
What is a parasite?
organism living in or on the host and
dependent on it for nutrition - causing
damage
Explain the broad classification of Parasites
- Endoparasites
- Protozoa
- Metazoa
- Ectoparasites
What are the characteristics of a protozoa?
Protozoa are a type of Endoparasites
- single-cell
- eukariotes
- everyone has different pathogenesis
- might be vecor-mediated
- non-eosinophilic defence
What are the characteristics of Metazoa?
Multicellular organisms (Helminths/worms) ((Endoparasites))
- Can be Free living, or have an intermediate hosts and vectors
- Some just inhabit gut (geohelminths), other invade tissues
- Eosinophilia – if invade blood
What are the different types of Protozoa?
Protozoa? Eukariotic single cell organisms
- amoeba
- coccidiae
- ciliate
- flagellates
Name examples of Amobae parasites
What kind of parasitic class are they?
Amobae= type of Protozoa
E.g.
- Entamoeba histolytica
- Entamoeba dispar
What are the symptoms and diagnosis of an Entamoeba histolytica infection?
Fecal-oral transmission
- humas are only reservoir
- Often: asymptomatic
- Amoeic parasited invade epithelium of large intestine: causing flask-shaped ulcers
- infection can spread to other organs: invasive
- often liver cyst but also: lung, kidney, heart brain
- infection can spread to other organs: invasive
- Diagonosis: Fecal micoscropy
What type of parasite are Coccidia?
What are their main characteristics and name an example
They are a type of Protozoa infection
Normally: zoological vectors
E.g.
- plasmodium causing Malaria
- Toxoplasma causing Toxoplasmosis
- Cryptosporidium causing Diarrhoea
Which pathogen causes Malaria?
What are the main symptoms?
Caused by: Plasmodium (different types with different severity) (Type of Coccidia)
- Liver stage (no symptoms)
- Blood stage: symptoms
Leading to
- Fever, headache, chills, vomiting, muscle pain
- Paroxysm (cycle in 4-8hrs) (spasm)
- Might lead to
- Severe anemia (destruction of red cells)
- Cerebral malaria (swelling of the brain,seizures, coma)
- many more
What is Toxoplasmosis?
What are the symptosm and what is it caused by?
Toxoplasmosis= Toxoplasma (type of Coccidia)
- In Immunocompetent: mild disease with fever, swollen lymph nodes, headaches, sore throat
- however, in pregnancy: toxoplasmosis poses serious danger for the Foetus
- In immunosupressed: serious diseae (eventually CNS disease)
- Transmitted by Cats/Cat poop (+ mice and birds)
What kind of parasite is Cryptosporidium?
What does it cause?
Coccidia (type of Protozoa)
Causing
- Fecal-oral transmission
- Diarrhoea
- mild in immunocompetent but
- might be severe in immunocompromised
- diarrhea, fever, nausea, vomiting
- common in HIV patients with Diarrhoea
What kind of pathogens are Ciliates?
Name examples
Ciliates= type of Protozoa
- E.g. Balantidium coli
What are the symptoms of someone with an Balantidium coli (Balantidiasis) infection?
What kind of infection is it?
It is a parasitic infection with a ciliate (type of protozoa)
causing
- asymptomatic in immmunocompetent
- In immunocompromised: persistent diarrhea, dysentery, abdominal pain, weight loss, nausea, and vomiting (might perforate colon)
What kind of pathogens are Flagellates?
Name examples
Flagellates= type of protozoa (endoparasites)
- E.g. Giardia lamblia (Giardiasis)
- Trichomonas
- Leishmania
What kind of pathogen is Giardia lamblia?
What does it caue?
It is a Flagellate Protozoa (33% of people in developing countries infected)
causing
- In most people: asymptomatic (but transmit diseae)
- If it caueses symtoms: Diarrhoea, Greasy stools,
abdominal cramps, nausea/vomiting,
- also fecal-oral transmission
What kind of pathogen are Trichomonas?
What do they cause?
Flagellate protozoa
Cause: Trichomoniasis:
- STD
- in many people: asymptomatic but might cause
- vaginal+ vuval infection and itching
- dysuria, inflammation of urethra (men)
- Might caue problems in Pregnancy –> low birth weigh
What are the different types of Helminths?
Helminths= metazoa
Can be classfied in
- Roundworms (Nematodes)
- Flatworms (Cestodes)
- Flukes (Trematodes)
What are Nematoes?
Name examples
Nematodes= Roundworms
- e.g. Ascaris,
- hookworm
- Filaria,
- Strongyloides
What kind of Infection is Ascarsis?
What does it cause?
It is a type of roundworm (Nematodes)
- live, mate and lay eggs in small intestine
- get into the hepato-circulation to the lungs
- mature in the lungs and creep up the thrat to be swallowed
- Causing: Ascariasis
- often asymtomatic (but people can transmit)
- if number of woms high enough: abdominal pain, intestinal obstruction
- mslnourishment
- pneumonia (penetration of larve in lung)
- Causing: Ascariasis
What kind of infections are Hookworms?
What do they caue?
Are a type of Roundowmrs (Nematode)
Causing
- enter through skin
- iron deficiency anaemia (deficient membrane causing bleeding due to attachment of worm in Small intestine)
- GI/ metabolic symptoms
- Resp symptoms: (larve penetrating alveoli)
What kind of parasites are Filaria?
Give examples
Filaria= type of Roundworms (Nematodes)
- E.g. Lymphatic filariasis
- Elephantiasis
- causing lymphatic obstructuion
What kind of parasites are Flatworms (cestodes)?
Name an example
Flatworms= type ofMetazoa
E.g. Taenia spp.
What are Tenia?
What do they cause?
Tenia=type of Flatworm (cestodes)
- vector mediated transmission (pig)+ cow
- often: asymptomatic
- but might cause
- digestive problems including abdominal pain, loss of appetite, weight loss, and upset stomach.
What is the Commonest acquired cause of epilepsy worldwide?
A cysticercosis resulting from an infection with Taenia solium (flatoworm) (cestodes)
What kind of parasites are Flukes (trematodes)?
Name an example
They are a type of Metazoa
E.g. Schistosomiasis
What are the symptoms of Schistosomiasis?
Eggs. have intermediate host: fresh water snail
- Symptoms
- Mostly Asymptomatic at early phase but if symptoms:
- within days: rash or itchy skin
- 1-2 Months: fever, chills, cough, and muscle aches
- inflammation and scaring of small intestine, liver bladder due to larve travveling in body
Name examples of Ectoparasites
- E.g. Scabies (Sarcoptes scabiei)
- Lice
What kind of parasite is Leishmania?
How is it transmitted?
What are the different types of Leishamania?
It is Flagellate Protozoa
- transmitted by a vector: the sandfly causing
- Visceral leishmaniasis
- Or cutaneous Leishmaniasis
What are the symptoms of visceral leishamaniases?
Also called: kala azar (Black fever)
- Hepato and Splenomegaly
- irregular fever, weight loss, anaemia
- invasion of macrophages
- fatal if left untreated
What are the symptoms of cutaneous leishmaniases
Three different severities
- Cutaneous leishmaniasis: localised lesions on exposed bodyparts,often self-healing (but can create scars + disabilities)
- Diffuse cutaneous leishmaniasis: disseminated lesions,resembles leprosy difficult to treat, no spontaneous healing, frequent relapses
- Mucocutaneous leishmaniasis: disfiguring, destroys mucous membranes
