Key Parasite, Fungi, Helminths Flashcards
Other Key organisms we must know — (C.A.P.S)
Other than bacteria or viruses
- Candida albicans
- Aspergillous
- Plasmodium falciparum
- Schistosomiasis
Structure of Candida albicans?
Fungi -> yeast
- unicellular
- gram positive
- diploid
- eukaryotic
- asexual reproduction
Location of C.albicans?
Commensal
- skin, intestinal tract, colon, mouth, vagina
Mode of infection of Candida albicans?
- When normal flora is depleted by antibiotics (not affected by antibiotics, so can proliferate without competition and cause infection)
- Opportunistic infection = immunosuppressed patients
> e.g. HIV +ve patients
Commonly linked conditions to Candida albicans?
Oral thrush
Vaginal thrush
Candidiasis = an AIDS-defining illness
Investigations of Candida albicans?
- stool sample, swab from infected areas. Then:
> Agar culture
Microscopy
Treatment of Candida albicans?
- immuno response = complement pathway
> MBL pathway = Initiated when MBL binds to mannose containing residues of proteins found on many microbes.
—> Antimicrobial actions of this pathway = C5-C9: Killing of pathogens Membrane Attack complex
Specific treatments =
Antimicrobials = Nystatin, clotrimazole, IV fluconazole
Structure of Aspergillous?
Fungi -> mould
- multicellular
- asexual reproduction
- spores & hyphae
- eukaryotic
Location of Aspergillous?
Normal commensal of cavity of lung
Mode of infection for Aspergillous?
Opportunistic infection
- Immunosuppressed host
- moving to different part of body
Common conditions liked to Aspargillous?
- Acute Pulmonary aspergillosis (Halo signs in HRCT scan of lungs)
- Pulmonary aspergillosis = presenting complaint of Chronic Granulomatous Disease (in immunosuppressed patients)
Investigations of Aspergillous?
- HRCT scan of lungs = see Halo signs
- culture
Treatment for Aspergillous?
Systemic fungal infection = IV Amophotericin B = inhibits cell membrane function.
Structure of plasmodium falciparum?
- unicellular Protozoa parasite.
Transmission of P.falciparum?
Mosquito vector
(Other cause of malaria = plasmodium vivax, plasmodium malariae)
(Incubation period for P. falciparum = 6 days to 6 months)
Mode of infection of P. falciparum?
1) Mosquito bite a human releasing sporozoites into the human which is transported in blood to liver cell (hepatocyte).
2)Merozites are form of the
parasite that is released
from human liver cell and
go on to infect human
blood cells.
3) In blood the merozite grow to a trophozite. These the mature to schizonts which divide several time to produce merozites. These new merozite can then differentiate to form gametocyte
4) eventually blood cells are lysed
And the parasites escape and infect more blood cells.
Common conditions linked to P. falciparum?
Malaria
- Hepatomegaly (infection of hepatocytes)
- Splenomegaly = inc. splenic activity to remove damaged RBCs
- Jaundice = (RBC destruction -> increased bilirubin
- cerebral malaria
- hypotension
- hypoglycaemia
- cardiac arrhythmias
Symptoms of P. falciparum?
Symptoms
- Headache
- Fever
- Fatigue
- Pain
- Chills
- Sweating
- Dry cough
- Splenomegaly
- Nausea
- Vomiting
Investigations of P. falciparum?
- travel history
- 3 Blood smears to confirm malaria
- FBC
- Urea and electrolytes
- Coagulation
- Head CT if CNS symptoms
Treatment of P. falciparum?
- Quinine
- Doxycycline
Structure of Schistosomiasis?
- parasite
- Helminth = multicellular, worms)
- Fluke
- incubation period = > 21 days
Location of Schistosomiasis
- fresh water
Transmission of Schistosomiasis?
- exposure to fresh water in an endemic area
Mode of infection for Schistosomiasis
- Originally Lives in a snail
- Snail Goes into fresh water
- Human exposed to infected water
- worm enters body and reproduces within patient body. (Lays eggs)
