Transcript Biology 331 Representative Eukaryotic Pathogens All over the book…

Biology 331
Eukaryotic Microbes
Eukaryotic Groups With Microbes
Algae - many chlorophylls, few pathogens
Fungi - structure groups, many pathogens
Protozoa - motility groups, many pathogens
Fig. 2.32, rRNA
Fig. 18.12, many genes/proteins
Mycology - More About Fungi
Fungi Features
Nearly all have chitin (NAG only) walls and…
Membrane ergosterols - antifungal drug target
Most differentiate - unicellular, hyphae, spores
Chemotroph decomposers - soil, water
Will NOT tackle book classification - too in flux!
Pathogenic Fungi
Mycoses grouped by depth - skip subcutaneous
Superficial = e.g. Trichophyton - athlete’s foot
Systemic = e.g. Candida - thrush, vaginitis
More About Protozoa
Protozoa Features
Unicellular, vegetative forms lack cell walls
Predatory chemotrophs, some make hardy cysts
Phenotypic Classification - motility groups…
DNA - new vs. old flagellates (no mitochondria)
Antiprotozoal drugs - agent/disease-specific,
major side effects, resistance issues
Old Flagellate - Giardia lamblia
Cysts - mammal GI, 97% freshwater, resists Cl
2-4 weeks - foul, greasy stool, sulfuric gas
Can become chronic in liver - cyclic diarrhea
90% infants/oral-fecal; 30% gay men/STD
30% developing – carry or have Ab/exposure
Drug: Flagyl inhibits e- carriers
Old Flagellate - Trichomonas vaginalis
Hydrogenosome - novel anaerobic organelles
No survival outside host - STD or perinatal
Females: vaginitis, yellow/foul discharge, pain
Males: asymptomatic carriers
Drugs: Flagyl; condoms = effective control
This is NOT a notifiable disease - even though it
likely causes 3 million US cases/year.
New Flagellate - Trypanosoma brucei
No survival outside host - insect-borne
African Sleeping - Tsetse Fly/Glossina saliva…
Fatal (0.5-2 yrs) – heart and/or CNS failure
Drug: Suramin halts metabolic enzymes
20,000 Africans die/year vs. 24 tourist deaths in
40 years (of 20,000 tourists to Africa/year).
New Flagellate - Trypanosoma cruzi
No survival outside host - insect-borne
Chagas - assassin/kissing bugs GI/feces
Mild flu-like to chronic heart/GI/CSF
Latin America: 16-18 million, 10% heart defects
Drug: Nifurtimox alkylates DNA
Disturbingly, US blood is not screened and this
is not a notifiable disease.
Amoeba - Naegleria fowleri
Cysts - free-living in soil, water, hot springs
Nose to brain - hemorrhagic encephalitis
Fast frontal headache, taste/smell loss, seizure
Death in days, 4 survivors/140 cases worldwide
Drug: Amphotericin B attacks membranes
Sporozoa - Plasmodium
No survival outside host - insect-borne
Tropical Anopheles bite to liver (1 hour) to RBC
Sickle cell carriers PROTECTED
Acute Malaria: fever, headache, anemia
Drug: Quinolones/Quinine binds DNA
US/DDT eradicated in 1950’s but re-emerging =
2000 cases/year, most airport-associated