Eukaryotic Organisms

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1 Eukaryotic Organisms A Pictoral Guide of Supportive Illustrations to accompany Select Topics on Eukaryotic Oranisms Bacteria (Not Shown) Agent of Disease Reservoir Vector By Noel Ways

2 Favorable Environmental Conditions induce Excystment Cyst Trophozoite Adverse Environmental Conditions induce Encystment Reproduction During Environmentally Favorable Conditions Page 2

3 Generalized Life Cycle Concepts and Terms Merozoites (1n) [ Infective ] Sporozoite (1n) [ Infective ] Trophozoite may be Merozite (product of Schizogony) may be Sporozite 8 cells (1n) in Oocyst (product of xxx) Mitosis Sporogamy Sporozoite (1n) Microgametocyes (1n) Male 4 cells (1n) in Oocyst Meiosis Schizogony also known as Merogomy (Asexual) Cells 1n Sporozoite (1n) Macrogametocyes (1n) Female Zygote (2n) in Oocyst Gametogony Asexual Reproduction Sexual Reproduction Page 3

4 BLOODAmoebiasis Life Cycle Entamoeba histolytica (invasive) Entamoeba dispar (non-invasive) Disseminated infection results in organ lesions /peritonitis and death Stomach Fecal / Oral Route Excystment in Small Intestine Encystment in Large intestine Note: blood invasion is rare Cysts Large Intestine Trophozoites (in Small Intestine) Ulcerations Fomites Food Feces Water Trophozoite Migration Page 4

5 Giardia lamblia Life Cycle Reservoir: Beavers strongly implicated. Also, many other wild animals as well as domestic animals Stomach Fecal / Oral Route Cysts Large Intestine Excystment in Small Intestine Small Intestines Trophozoites Fomites Food Feces Water Page 5

Toxoplasma gondii Life Cycle Some Parasites undergo Metamorphosis Microgametocytes (n) Macrogametocytes (n) Zygote or Oocyst (2n) Cysts (n) injested by Cats excyst and parasite now enters intestinal

Digestive Tract of Cat (Difinitive Host) Intermendiate Hosts Excreted in Feces Oocyst released in feces undergo meiosis followed by mitosis Occurs in Environment Ingestion of Sporozoites by animals,

6 Toxoplasma gondii Life Cycle Some Parasites undergo Metamorphosis Microgametocytes (n) Macrogametocytes (n) Zygote or Oocyst (2n) Cysts (n) injested by Cats excyst and parasite now enters intestinal tract where they multiply and invade host. Digestive Tract of Cat (Difinitive Host) Intermendiate Hosts Excreted in Feces Oocyst released in feces undergo meiosis followed by mitosis Occurs in Environment Ingestion of Sporozoites by animals, particlarly rodents, maintaines organism in nature as cysts (n) form and are repeatedly rupture, reinfect, & injested. Ooyst now contains 8 sporozoites Sporozoites (n) are infectious Present in water food and soil Infected Undercooked Food Fecal Contamination Immuno- Compromised Person Latent Infection (Cysts) in Nervous System (and other organs) Human Toxoplasmosis Pass Through Placenta Fetal Deformaty / Death Page 6 Acute Infection

7 Paragonimus westermani Life Cycle Cercaria penetrate and encyst forming Metacercaria within tissue. Man eats undercooked crustaceans and metacecariae develop into flukes which migrate to lungs and other organs. In lungs, eggs produced are coughed up and swallowed, thereby leaving via feces. Cercaria seek out crayfish or crabs. Miracidia penetrate species specific snail. Forms Redia Embryonated Eggs hatch. Redia asexually reporduce. Within rediae, cercaria are produced. Note tails. Cercaria will bore out and leave snail. Cercaria Redia Page 7 Miracidia develop and seek out species specific snail. References: Parasitology by Noble and Noble Microbiology by Tortora

8 Taeniarhynchus saginatus Life Cycle Head Evaginates and hooks into small intestine of man Undercooked Beef Tapeworm develops Larvae encysts in skeletal muscle Cows, Buffalo, etc. Larvae travels via blood stream to skeletal muscle Embryo liberated Eggs freed from gravid proglotids Gravid proglotids pass in feces of man Page 8

9 Ascaris lumbricoides Life Cycle 5 8. Larvae ( ) hatch and bore through intestinal mucosa. 9. Enter hepatic portal system and migrate to liver, then right heart and then lungs. 1. Sexual Reproduction results in copious egg ( ) production (~200,000 / day) 2. Fertilized eggs passed in feces Larvae enter alveoli. Patient may experience severe ascaris pneumonitis at this time. 11. Tracheal Migration. Larvae migrate up respiratory tree to pharynx. 3. Embryo develops within egg case 10 4 Larvae in Egg 4 Development continues, larvae form. 5. Fecally contaminated food with embryonated eggs ( ) injested Fertilized Eggs Larvae are now reflexively swallowed. 6. Embryonated eggs swallowed 7. Pass through stomach and enter small intestine 3 Development Pass through stomach. 14. Enter small intestine and develop into adults. Cycle now repeats: (start back at 1). Embryonated Egg Fertilized Egg Page 9 References: CDC ( An Illustrated Laboratory Text in Zoology by Boolootian and Heyneman c 1991

LIFE CYCLE OF THE DEER TICK Eggs Uninfected (Vector for Borelia bergdorferi, agent of LYME DISEASE) Eggs are never infected Larvae (Six Legged) Summer (Year 1) Infected Blood Meal Results in

vertebrates, particularly rodents, are "reservoir" for the disease causing agent of Lyme Disease.

10 LIFE CYCLE OF THE DEER TICK Eggs Uninfected (Vector for Borelia bergdorferi, agent of LYME DISEASE) Eggs are never infected Larvae (Six Legged) Summer (Year 1) Infected Blood Meal Results in Infected Larvae if rodents harbor bacterium Blood Meal Results in the innoculation of small vertebrates Nymph (Eight Legged) (Year 1) Fall --> Winter Nymph Spring Page 10 Spring Small vertebrates, particularly rodents, are "reservoir" for the disease causing agent of Lyme Disease. Nymph Summer (Year 2) Should man inadvertently be fed upon by an infected nymph or adult deer tick, the bacterium of Lyme Disease will be transmitted (Year 2) Nymphs Over-winter (Year 1) Adults preferentially will mate on White Tail Deer or shorty after feeding upon them Fall (Year 2) Adults Eggs Over-winter

Eukaryotic Parasites. An Illustrated Guide to Parsitic Life Cycles to Accompany Lecture. By Noel Ways

Eukaryotic Parasites. An Illustrated Guide to Parsitic Life Cycles to Accompany Lecture. By Noel Ways Eukaryotic Parasites An Illustrated Guide to Parsitic Life Cycles to Accompany Lecture By Noel Ways Giardia lamblia Life Cycle Reservoir: Beavers strongly implicated. Also, many other wild animals as well