Fungi, Algae, Protozoa & Arthropod Vectors

1. Fungi, Algae, Protozoa & Arthropod Vectors

2. Fungi • Ubiquitous! • Have a cell wall = chitin • Are eukaryotes • Have a true nucleus • Reproduce sexually + asexually • Most don’t cause disease • Disease can be direct (infection) or indirect (ingestion of toxin produced by the fungus)

3. Coccidiodesimmitis Domain: Eukarya Kingdom: Fungi Etiologic agent of coccidioidomycosis (“Valley fever”) Narrow environmental range: semi-arid zones of SW US, Mexico, Central & South America Dimorphic fungus: Saprophytic: environmental temp - filamentous fungus (mold) with branching septatehyphae + arthroconidia Parasitic: body temp: yeast form – large fungal spherules + division (endosporulation) to produce endospores Arthroconidia → spores → inhalation by mammals → spherules → endospores “Imperfect fungus” – no known sexual stage

6. Algae • Aquatic or semi-aquatic environments • Have a cell wall (cellulose) • Are eukaryotes • Have a true nucleus • Photosynthetic (chloroplasts) • Reproduce sexually + asexually • Disease most often = indirect (toxic algae)

7. Algae: Cyanobacteria Most common causes of toxic blooms: Anabaena, Aphanizomenon, and Microcystis species Hepatotoxic: cause acute submassive to massive hepatocellular necrosis → liver failure

8. Algae: rarely cause infectious disease Chlorella species Protothecawickerhamii

9. Slime molds and water molds • Slime molds: ameboid cells • Phagocytic • Cellular slime molds: single cells, can aggregate to form a “slug” → fruiting body + spores → dissemination • Plasmodial slime molds = multinucleated; diploid cells; also spread by fruiting body/spores • Water molds = oomycetes • Cell wall = cellulose • Flagellated

10. Pythiuminsidiosum Domain: Eukarya Kingdom: Protista Oomycete (Water mold) Etiologic agent of pythiosis (“Kunkers”) Warm, wet environments

11. Pythiuminsidiosum

12. Protozoa • Eukaryotes that don’t fit into any of our other categories • True nucleus • No cell wall, no chloroplasts • Reproduce sexually + asexually • Most don’t cause disease • Disease causing protozoa can be free living/opportunists or obligate intracellular parasites with a complex life cycle

13. Toxoplasmagondii Domain: Eukarya Kingdom: Protista Apicomplexan Etiologic agent of toxoplasmosis

14. Life cycle of Toxoplasmagondii Int. hosts Definitive host

15. Vector transmitted diseases • vec·tor  (vktr)n.1. Mathematicsa. A quantity, such as velocity, completely specified by a magnitude and a direction. • b. A one-dimensional array. • c. An element of a vector space. • 2. Pathology An organism, such as a mosquito or tick, that carries disease-causing microorganisms from one host to another. • 3. Genetics A bacteriophage, plasmid, or other agent that transfers genetic material from one cell to another. • 4. A force or influence. • 5. A course or direction, as of an airplane.

16. Vector transmitted diseases • Mechanical vectors • Biological vectors • Arboviruses

17. Plasmodium species Domain: Eukarya Kingdom: Protista Etiologic agent of malaria – 5 species involved = P. vivax, P. falciparum, P. malariae, P ovale and P. knowlesi Vector = Anopheles species mosquitos

18. Life cycle of Plasmodium sp.

19. Rickettsiarickettsii Domain: Prokarya Kingdom: Bacteria Vector: ticks – Dermacentorandersoni, Dermacentorvirabilisand Rhipocephalus sanguineous) Disease: Rocky mountain spotted fever

23. 3 host tick life cycle