- Unicellular - Eukaryotic organisms - Can use insect/ water vectors

(PM3A) Parasitic Infection + Anti-Parasitic Drugs Flashcards by Nikki Gurung

How does a parasite meet its nutritional needs?

Prolonged contact with another living organism

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What is an example of a unicellular parasite?

Protozoa

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What is an example of a multicellular parasite?

Helminths

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What are the two classes of parasites?

(1) Endoparasites

(2) Ectoparasites

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What are examples of endoparasites?

(1) Protozoa

(2) Helminths

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What are examples of ectoparasites?

(1) Lice

(2) Leeches

(3) Scabies

(4) Fleas

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What are the main anti-protozoal drugs?

(1) Anti-amoebics

(2) Anti-malarials

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(1) What is the mechanism of action for pyrimethamine?

(2) What is pyrimethamine?

(1) Inhibits DHFR

(2) Anti-protozoal drug

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(1) What is mechanism of action for sulphadiazine?

(2) What is sulphadiazine?

(1) Inhibits DHPS

(2) Anti-protozoal drug

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What is the mechanism of action of doxycycline?

Inhibits protein synthesis in 30S ribosomes

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What are the main anti-helminth drugs?

(1) Anti-nematodes

(2) Anti-cestodes

(3) Anti-trematodes

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Name 3 common anti-helminth drugs: m p n

mebendazole
praziquantel
niclosamine

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What is the mechanism of action of mebendazole?b ms gu

(1) Binds to beta-tubulin in intestinal cells of nematodes

(2) Prevents microtubule synthesis

(3) Leads to block of glucose uptake

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What is the mechanism of action of praziquantel?ca mp

(1) Increases membrane permeability to Ca2+

(2) Leading to contraction of muscle and paralysis

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What is the mechanism of action of niclosamine?

(1) Uncouples oxidative phosphorylation

(2) Prevents ATP synthesis

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What are protozoa?

Unicellular
Eukaryotic organisms
Can use insect/ water vectors

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Give examples of protozoal infections.

(1) Malaria

(2) Intestinal infections - amoebic dystentery/ toxoplasmosis

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How is a malaria infection diagnosed?

(1) Blood film microscopy

(2) Antigen-based rapid diagnostic tests (RDT)

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What are the stages of malaria transmission?

(1) Mosquito bites + injects sporozoites

(2) Infects liver cells

(3) Development of a schizont.

(4) Schizont ruptures

(5) Releases merozoites -> Infect erythrocytes -> Immature trophyzoites

(6) Some immature trophozoites mature to develop more schizonts

(7) Some generate gametocytes - which are ingested by mosquitos

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What is a schizont?

A protozoan cell which divides to form daughter cells

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What are the symptoms of malaria?

Fever/ chills/ sweats
Headaches
Nausea + vomiting
Aches
Malaiase

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What can severe malaria cause?

Cerebral malaria
Organ damage
Metabolic damage

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How can malaria be prevented?

(1) Anti-malarial drugs
(2) Covering
(3) Mosquito nets
(4) Permethrin - insecticide
(5) Vaccine

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What are the main malaria prophylaxis medications in the UK?

(1) Doxycycline
(2) Mefloquine
(3) Proguanil + atovaquone (Malarone)

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What is 1st choice treatment for P. falciparum malaria?

(1) Clindamycin (2) Proguanil + atovaquone (Malarone)

What is the 1st line treatment for malaria in pregnancy?

Quinine + clindamycin

What does malaria have widespread resistance to?

(1) Chloroquinine (2) Anti-folates

What is amoebic dysentery?

Amoebiasis Infection of amoeba fecal oral transmission Causes diarrhoea

What is the treatment for amoebic dystentery (amoebiasis)?m

Often self-limiting Metronidazole - for acute invasive amoebiasis

When can a toxoplasmosis infection be life-threatening?

If immunocompromised

What is the treatment for toxoplasmosis?

Often self-limiting Pyrimethamine + sulphadiazine

What is cryptosporidiosis?

Parasitic infection Causes diarrhoea

How is cryptosporidiosis transmitted?pl fs

(1) Swimming pools/ lakes (2) Contaminated foods + surfaces

What are the symptoms of cryptosporidiosis?

- Watery diarrhoea - Dehydration - Weight loss - Stomach cramps/ pain - Fever - Nausea + vomiting

When is cryptosporidiosis life-threatening?

If immunocompromised

What is the treatment for cryptosporidiosis?n

Usually self-limiting and not treated Nitazoxanide if required

What are helminths? How many types are there? What are they?

Parasitic worms 3 types (1) Cestodes (2) Nematodes (3) Trematodes

How are helminths transmitted?m cw f i

(1) Poorly cooked meat (2) Contaminated water (3) Faeces (4) Insects - such as mosquito

Where are most species of helminth present?

Intestinal tract

What are subtypes of cestodes?

(1) Cestodaria - less common (2) Eucestoda - more common

What is a scolex?

The head of a cestode

What are proglottids?

Body segment of a cestode

What are the common symptoms of a cestode infection?a ad d

(1) Upper abdominal discomfort (2) Diarhhoea (3) Loss of appetite Often asymptomatic - Worm segments can sometimes be seen in stool

How is a cestode infection treated?

(1) Niclosamide (2) Praziquantel

What is the cause of a threadworm infection?

Usually transmission of eggs Faecal-oral Eggs in faeces

How is a threadworm infection diagnosed?

(1) Seeing worms in perianal region (2) Scotch tape test - Sellotape around anus in morning - Attaches worms & eggs to tape

How is a threadworm treated?

Mebendazole Good hygiene

What is a threadworm?

Type of nematode Type of helminth Parasite

What is a hookworm?

Type of nematode Type of helminth Parasite

What are the symptoms of a hookworm infection?i d n i

(1) Iron-deficient anaemia (2) Diarrhoea (3) Nausea & vomiting (4) Severe local irritation - from larvae in skin

What is the treatment for a hookworm infection?

(1) Cryotherapy (2) Mebendazole - 100mg - BD - 3 days

How is a whipworm infection caused?

(1) Eggs hatch in the small intestine (2) Eggs develop in the wall of the intestine

How length can a whipworm grow to?

50mm 2 inches

What are the symptoms of a whipworm infection?a bd

Light infestations - asymptomatic Heavy infestations - bloody diarrhoea & iron-deficiency anaemia

How is a whipworm infection diagnosed?

Stool examination Infestation is detectable in stool

What is the treatment for a whipworm infection?

Mebendazole - 100mg - BD - 3 days

What is another name for a roundworm?

Ascaricides

How many people worldwide are infected by roundworms?

1 billion

How long is a roundworm?

Up to 50cm long

What are the symptoms of a roundworm infection?a t p nd

(1) Often asymptomatic (2) Peritonitis/ Inflammation/ Visceral damage (3) Enlargement of liver/ spleen (4) Toxicity (5) Pneumonia (6) Nutritional deficiency

What are complications of a roundworm infection?

(1) Obstructed bowel - by a bolus of worms (2) Obstruction of bile duct (3) Obstruction of pancreatic duct

What is the treatment for a roundworm infection?

(1) Mebendazole - 100mg - BD - 3 days (2) Mebendazole - 500mg single dose

What are the general treatments for nematodes?

(1) Good hygiene (2) Anti-helminthics - Mebendazole 100mg

What are the different types of fluke?

(1) Blood flukes (2) Tissue flukes - Liver fluke - Lung fluke

Praziquantel can be used to treat

tissue fluke blood fluke lung fluke

What is/ are another name(s) for a blood fluke infection?

(1) Schistosomiasis (2) Bilharziasis

What is different about schistosomicides to other trematodes?

Male and female Other trematodes are not

What are the symptoms of schistosomiasis (bilharziasis)?

(1) Transient dermatitis - swimmer's itch (2) Dermatitis - abdominal pain - bloody stool - periportal fibrosis - hepatosplenomegaly - CNS effects

What is peri-portal fibrosis?

(1) Chronic disease (2) Late-stage complication of schistosomiasis (3) Due to presence of eggs in portal venules

What is hepatosplenomegaly?

(1) Disorder of spleen and liver (2) Swelling of organ beyond normal size

What is a portal venule?

A division of the hepatic portal vein

What is the treatment for schistosomiasis (bilharziasis)?

Praziquantel - 20mg/kg - BD/ TDS

What is scabies?

Contagious skin condition where mites burrow into the skin

What is/ are the treatment(s) for head lice? How does it/ they work?

Dimeticone lotion/ liquid - Suffocates lice - physical treatment Wet combing - Mechanical removal

What is the treatment for scabies?

Permethrin 5% cream - (Topical) Ivermectin (Oral)

(PM3A) Parasitic Infection + Anti-Parasitic Drugs Flashcards

(75 cards)