What is the incubation and the symptoms associated with E.histolytica (an amoeba) infection
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
T/F e.histolytica also infects other mammals
F Humans are the only reservoir,
Outline how E. histolytica gains access to the body and its effect on GI tract
enter the small intestine and release active amoebic parasites (trophozoites), These invade epithelial cells of large intestine --> ULCERS
How can E. histolytica escape the GI tract and invade other structures
Infection can then spread from the intestines to other organs, e.g. liver, lungs and brain, via the venous system.
What is the effect of invasive amoebiasis
most often causes an amoebic liver abscess, but may affect the lung, heart, brain, urinary tract and skin.
Can the disease be spread by asymptomatic carriers?
Yes Asymptomatic carriers pass cysts in the feces and the asymptomatic carriage state can persist indefinitely. Cysts remain viable for up to 2 months.
Diagnoss of amoebiasis? Treatment?
Wet mount (look for in stools) Nitroimidazole derivatives (act on trophozoite, but not on cysts)
T/F coccidia infections, in the same way as E. histolytica (which is invasive amoeba), is only a human disease
F.Coccidial infection in humans are mostly zoonoses
Examples of coccidia
Plasmodium species (malaria) Toxoplasma (toxoplasmosis, fine normally but v dangerous for foetus) Cryptosporidium (diarrhoea in immunocompormised)
Route of infectin for coccidia
Mosquito borne Cats Water
Explain what is meant by a vector and list two specific examples, naming the diseases they transmit.
Malaria (plasmodium from coccidian protozoa) --> female Anopheles Loa loa eye infection=loaiasis (=.filaria roundworm metazoa) Vector is chrysops.
Types of plasmodium
P. falciparum, P. malariae, P. ovale, P. vivax and P. knowlesi
Types of host for malaria (plasmodium)
humans and female Anopheles mosquitoes Bite at night, breed in water
Stages of the life cycle that occur in human for malaria
Liver and blood stages then mosquito stages too
Symptoms of malaria, and when do they appear
Variable.... 7 days to months Fever, headache, chills, vomiting, muscle pain,PAROXYSMAL (occurs every 4-8 hours)
Complication of malaria
Cerebral malaria (swelling of the brain,seizures, coma) Severe anemia (destruction of red cells)