1. PROTOZOA First Animal

2. Parasite Lives at expense of host Ectoparasites Endoparasites
Ticks & lice
Endoparasites
Protozoan & worms

3. Characteristics of Protozoa
Unicellular eukaryotes
Key part of food chain
Most free living, decomposers especially sewage

4. Characteristics of Protozoa
Some commensals- no harm
Guts of termites, roaches, ruminants
Some parasites
Most motile by cilia, flagella or pseudopodia

5. Morphology Diverse Lack rigid cellulose cell wall Trophozoite
Pellicle or membrane
Trophozoite

6. Morphology Many have resting stage-cyst Not reproductive structure
Intestinal bugs pass host to host

7. Reproduction Asexual Sexual Fission, budding Schizogony Gametes
Oocyst-Apicomplexa

8. Nutrition Aerobic, mostly chemoheterotrophic (engulf food)
One group is photoautotrophic
Some anaerobic growth; live in intestine
Some transport food across membrane

9. Nutrition Some ingest food Ciliates have cytostome
Amoebae engulf food via pseudopods
Digestion takes place in vacuoles- (lysosomes), waste through PM or anal pore

10. Virulence factors Waste products (toxins) produce disease-malaria
Hide from immune system
Some grow inside phagocytes
Some change antigens

11. Archaezoa Lack mitochondria
Evolved before endosymbiotic event or lost ability to produce mitochondria

12. Archaezoa Many live as symbionts Trophozoite
Spindle shaped with 2 or more flagella

13. Trichomonas vaginalis
Vagina and male urinary tract( asymptomatic)
No cyst form
needs to be transferred before drying
Transmitted via sex , toilet facilities or towels(moist)

14. Trichomonas vaginalis
Environmental changes DT abxs, DM, or IUD-infection
S&S increase in WBCs
Prevention-abstinence, monogomy, condoms

15. Giardia lamblia Tophozoite Survives in environment long time
Excreted in feces as cysts
Survives in environment long time
Ingested by host or transferred during anal intercourse
Cyst resistant to chlorine & stomach acid

16. Giardia Metronidazole, flagyl used for anaerobes damages DNA
Diapers in day care
Enterotest capsule-gelatin with string

17. Amoebozoa
Amoebas
Pseudopodia for phagocytosis
Entamoeba histolytica ( tissue lysing)- amoebic dysentery (Blood in stools)
Trophozoites in small intestine -food is RBCs
Cysts excreted in feces of infected person-MSM

18. Entamoeba histolytica
Forms ulcers by digesting wall of large intestine
Can enter blood stream
Infect other organs of body

19. Apicomplexa Nonmotile in mature forms All are parasitic
obligate intracellular parasite
Presence of a complex of special organelles at tips of cells
Oocysts are reproductive

20. Plasmodium Causes malaria
Characterized by shaking chills,feve & sweats
Symptoms occur at regular intervals-2 to 3 days
ID species
Vector is Anopheles mosquito

21. Plasmodium
P vivax, one of 4 species- most prevalent species but benign
 Sexual reproduction in gut
·  Infective sporozoites in saliva

22.     Life Cycle
·Transmit to humans (bite) and 100s go to liver where schizogony occurs –merozoites
·  Enter RBCs where develop into ring stage

23. Life Cycle · Multiply, forms merozoites and burst
·  Some merozoites develop into gametes
Enter gut of mosquito
Forms oocyst in wall of intestine
Cell division forms sporozoites and migrate to salivary glands

24. Life Cycle Definitive host is mosquito-sexual cycle
Intermediate host -human- asexual cycle
Diagnosis by blood smear and interval of symptoms .
Regulated by host’s body temperature

25. P. falciparum Most dangerous; “malignant malaria
Black water fever
Untreated malignant kills 50% of infected persons
Suppressed immune system and caused severe anemia
RBCs stick to capillaries causing blockage
tissue death -liver ,kidney and brain

26. Treatment Treatment is chloroquine for early stages
Primaquine for late stages
Resistance has developed

27. Immunity If survive malaria , have limited immunity
Sickle cell trait persons are relatively resistant to malaria
RBCs sickle under low oxygen tension
Microbe can’t survive

28. Control Program Need an effective program Increase in world population
Increase in warming
Increase in resistant Plasmodium strains
Increase in mosquito resistance to insecticides
Different stages of life cycle require different medications

29. Toxoplasmosis Agent Toxoplasma gondii Definitive host -cat,
Oocyst shed in feces
Form trophozoites-tachyzoites(fast)
Multiply in host tissues-all cells except RBCs
Intracellular parasite ruptures cells

30. Signs & Symptoms Fever, malaise, sore throat, swelling of lymph nodes
Immune system contains disease-chronic infection
Tissue cyst forms containing bradyzoites
Reactivate later when immune system breaks down
Can form lesions on eyes or any other organ

31. Life Cycle
Humans ingest undercooked meat or contact with cat feces- contain oocysts
Trophozoites released and feed on bacteria and fecal material
Most have mild symptoms unless immunocompromised

32. Infection
Congenital infections result in brain damage or vision problems in fetus
·  AIDS -severe eye damage from reactivation of cysts

33. Euglenozoa
2 groups
Hemoflagellates-blood parasites
Transmitted by bites of insects and found in circulatory system
Trypanosomiasis- 2 species of Trypanosoma
One causes a wasting disease: other acute, rapid progression to coma & death

34. African Sleeping Sickness
Affects nervous system, encephalitis
Multiples by fission inside of insect
Vector tsetse fly (salivary glands), reservoir is game animals
Infects human when defecates during biting
Forms painful chancre (syphilis)
Pathogen in blood then goes to liver, lymph nodes & CSF
Decrease in mental acuity and physical activity; untreated coma and death

35. Virulence Factor Evades immune system-changes antigens
Coincides with increase in parasites in blood
Continues till death or effective treatment
> 1000 genes coding for different antigens on surface
Few antiprotozoan drugs for treatment
Toxic

36. Ciliophora Ciliates, most are free living
Arranged in precise rows on cell
Move in unison to propel organism and to push food toward mouth
Balantidium coli-only human pathogen in this group
causes rare dysentery
reservoir is usually pigs
Cause ulcer to form in colon when trophozoites burrow into colon