Parasitology

Organism Toxoplasma g.

Type Protozoa

Transmission/Entry Undercooked meat, cat poop

Life cycle Ingest cyst

Immune stuff

 Plasmodium (falciparum)

Protozoa

Mosquito (v (very efficient transmission)

Sporozoite into  bloodstream  liver 

Giardia l.

Prot Protoz ozoa oa

  E. Histolytica

Protozoa

Cons Consum umpt ptio ion, n, such such as in contaminated water   small intestine. Consume cyst form

Consumption of  cyst form – then  trophozoite. Cyst  trophozoite.

Vivax strain cannot infect Duffy a / b  persons Cleared by CMI, usually 23 weeks.

 N. fowleri Trypanosomiasis

Protozoa Protozoa

SWIMMING Tsetse fl fly

T. Cruzi

Protozoa

 Leishmania

Protozoa

Sandfly

Trichuris trichiura  Ascaris lumbricoides

Roundworm Roundworm

Ingestion of eggs Ingestion of eggs  SI, such as in food

 N. Americanus Americanus + A. duodenale

Roundworm “hookworm”

Strongyloides  stercoralis

Roundworm

Larva can penetrate skin Penetrate skin

 Loa loa

Roundworm

Tabanid fly

Reduviid bug  bites/deposits  bites/deposits feces.

Bite  trypomastigote spreads in  bloodstream to lymph nodes / CNS.

Avoids destruction through antigenic variation

Enter as trypomastigotes, then form amastigotes. Promastigotes engulfed by macrophages.

No invasion Penetrate through intestinal wall  lungs or through skin  alveoli  coughed up/swallowed  adult worms in SI  release eggs. Cycle can repeat.

Pathology/Symptoms Transmitted x the placenta, especially if woman is infected during pregnancy  birth defects. Toxic to brain/ eyes in AIDS patients. Can present like mononucleosis. In liver, infects hepatocytes, divides, cells burst. Then, they infect RBCs, feed off Hb, then they burst. Cyclical fevers, chills, headaches, anemia, hepatosplenomegaly. hepatosplenomegaly.  Falciparum is most severe – CNS, lung problems. Adheres but doesn’t invade brush border of duodenum  malabsorption malabsorption of stuff bloating/flatulence, steatorrhea, weight loss. Invasion of colon  necrosis/cell necrosis/cell death  dysentery/bloody dysentery/bloody diarrhea, megacolon. Enter portal  liver abscess (pain, WL) ( lung abscess). Meningitis: fever, stiff neck, nausea, vomiting, headache. Ulcer @ bite site, fevers, headaches, lymphadenopathy, lymphadenopathy, malaise, weight loss, symptoms resolve; then intermittent fevers, finally progression to encephalitis/meningitis as  personality changes, sleepiness, coma, death. Gambiense (W. Africa) = milder/more chronic, human host. Rhodesiense host. Rhodesiense (E. Africa) = more acute/worse, zoonosis: painless chancre. Amastigotes infect macrophages, lymph nodes, and  bloodstream. Chagas’ Disease: acute phase = chagoma @  bite site, fever, lymphadenopathy, lymphadenopathy, malaise, then asymptomatic, asymptomatic, then recurs with megacolon, megaesophagus, esophagus, cardiomegaly/arrhythmias Cutaneous: chancres that heal, mucocutaneous: chancre heals, then later oropharyngeal ulcers  damage face, or  visceral = invasive: fevers, anemia/weight loss, thrombocytopenia, hepatosplenomegaly. Intestinal infection – abdominal pain / diarrhea. Mostly mild/asymptomatic: abd. pain, dysentery/intestinal infection. Lung: cough, SOB. Severe cases affect bile ducts/gall bladder, liver   malnutrition because of  competition for nutrients and/or mechanical blockage. Suck blood in SI  anemia, also diarrhea, abd. pain, WL, rash at site. Presence in lung  cough or pneumonia. Anemia, abdominal pain, diarrhea, vomiting, bloating. Rash @ site of entrance and lung symptoms are possible.

Mostly asymptomatic; can have edema/swelling due to

W. bancrofti

Roundworm

Many mosquito species

Larvae enter skin through mosquito  bite, grow up to be adults.

Onchocerca volvulus

Roundworm

Blackfly

 Dracunculus medinensis

Roundworm

 D. latum/T. saginata

Tapeworm

T. solium

Tapeworm

Consume the microcrustacea in drinking water  Consume in beef   ( saginata ), fish for  latum. Consume eggs or  larvae in pork 

Larvae infect, go through sub-q, then are adults Out of crustacean  thorax, mature/mate Cysts in muscles of  meat are consumed, form adult in the SI Eggs  adults in the SI.

 Echinococcus  granulosus

Tapeworm from dogs

Consume oncospheres

Eggs hatch in intestine  larvae

Schistosoma mansoni, haemotabium

Tapeworm

Released by snails into water / baby worm penetrates through skin

Cercariae  schistosomulae that circulate. Skin  liver – mate in liver.

 Paragonimus

Fluke

Baby worm through diaphragm, then into lung.

 Fasciola hepatica

Fluke

Eggs in fresh water   consume (cercariae) in shellfish Often eat in watercress/water  chestnut

Sarcoptes scabei

Mite

Tunga penetrans

Flea

Lice

Hair

Baby worm in intestine,  perforates, through liver, up to bile tract, eggs there.

Immune response   pruritus.

Inhibit complement and CMI.

Molecular  mimicry.

host responses. Worms on/in the eye  swelling Microfiliariae go into lymphatics  lymphadenitis + fever, inguinal swelling, edema, possible elephantiasis through fibrosis/blockage of lymph drainage months later. Toxin released after death of adult worms can cause damage. Incubation before symptoms.  Nodules are adult worms - painless. Skin: loss of   pigmentation if long-term infection, also pruritic rash can occur. River blindness if parasites die near/in the eye. Offspring go to extremities and often come out of foot. Symptoms at egress site: hives, inflammation, also vomiting, diarrhea. Mostly asymptomatic, can have weight loss/malnutrition.  Latum can impair  B12 in particular, anemia. Consume larvae: attach to wall of SI  malnutrition. Consume eggs: mostly asymptomatic except cysticercosis: oncospheres can go to brain. Can cause neuro symptoms; worse if they die in brain: encephalitis, seizure, etc. Usually asymptomatic. Larvae penetrate intestinal wall, then throughout the body, esp. liver (abd. pain, biliary obstruction), but also lungs (chest pain, hemoptysis). Acute: dermatitis @ site of entry; later, there’s fever, chills, headache, lymphadenopathy. In vessel: attach to wall / release eggs  inflammation  fibrosis and also impair flow. Liver: eggs  fibrosis, PHTN, varices, splenomegaly. Long-term: granulomas, cirrhosis. Long term haemotabium of bladder  inflammation  squamous cell cx. Penetrate intestinal wall  peritoneal cavity  diaphragm  pleural area. Inflammatory mass in lung  coughed up in rusty brown sputum/hemoptysis, inflammation. Live in liver/biliary tract. Try to get into feces/out of body. Acute: abdominal pain, hepatomegaly, fever, vomiting diarrhea. Chronic: in bile ducts – obstruction.

6-8 weeks after infection = immune reaction – dermatitis. Burrow into epidermis. Burrows into skin – usually painless, then can be itching, irritation, ulceration – can progress to infection/gangrene. Feed daily on blood. Specific to the animal.