Parasite: part 2

Question 1

What is the incubation and the symptoms associated with E.histolytica (an amoeba) infection

Answer 1

90% of infections are asymptomatic; rest range from dysentery to amoeba liver abscess Incubation as short as 7 days. Invasion occurs during first 4 months

Question 2

T/F e.histolytica also infects other mammals

Answer 2

F Humans are the only reservoir,

Question 3

Outline how E. histolytica gains access to the body and its effect on GI tract

Answer 3

enter the small intestine and release active amoebic parasites (trophozoites), These invade epithelial cells of large intestine –> ULCERS

Question 4

How can E. histolytica escape the GI tract and invade other structures

Answer 4

Infection can then spread from the intestines to other organs, e.g. liver, lungs and brain, via the venous system.

Question 5

What is the effect of invasive amoebiasis

Answer 5

most often causes an amoebic liver abscess, but may affect the lung, heart, brain, urinary tract and skin.

Question 6

Can the disease be spread by asymptomatic carriers?

Answer 6

Yes Asymptomatic carriers pass cysts in the feces and the asymptomatic carriage state can persist indefinitely. Cysts remain viable for up to 2 months.

Question 7

Diagnoss of amoebiasis? Treatment?

Answer 7

Wet mount (look for in stools) Nitroimidazole derivatives (act on trophozoite, but not on cysts)

Question 8

T/F coccidia infections, in the same way as E. histolytica (which is invasive amoeba), is only a human disease

Answer 8

F.Coccidial infection in humans are mostly zoonoses

Question 9

Examples of coccidia

Answer 9

Plasmodium species (malaria) Toxoplasma (toxoplasmosis, fine normally but v dangerous for foetus) Cryptosporidium (diarrhoea in immunocompormised)

Question 10

Route of infectin for coccidia

Answer 10

Mosquito borne Cats Water

Question 11

Explain what is meant by a vector and list two specific examples, naming the diseases they transmit.

Answer 11

Malaria (plasmodium from coccidian protozoa) –> female Anopheles Loa loa eye infection=loaiasis (=.filaria roundworm metazoa) Vector is chrysops.

Question 12

Types of plasmodium

Answer 12

P. falciparum, P. malariae, P. ovale, P. vivax and P. knowlesi

Question 13

Types of host for malaria (plasmodium)

Answer 13

humans and female Anopheles mosquitoes Bite at night, breed in water

Question 14

Stages of the life cycle that occur in human for malaria

Answer 14

Liver and blood stages then mosquito stages too

Question 15

Symptoms of malaria, and when do they appear

Answer 15

Variable…. 7 days to months Fever, headache, chills, vomiting, muscle pain,PAROXYSMAL (occurs every 4-8 hours)

Question 16

Complication of malaria

Answer 16

Cerebral malaria (swelling of the brain,seizures, coma) Severe anemia (destruction of red cells)