Sgu Parasitology Text Review 2010

Front 1

Trypanosoma Cruzi (Protozoa) "American Trypanosomiasis (Chagas)"

Back 1

Hosts: Possum, Armadillo, Rodents, Humans.
Location: South & Central America
Transfer: Reduviid Bugs (blood suckers): Triatomids, Rhodnius, Panstrongylus. Night feeders. Xfer by feces enter mucus membrane or wound. Vertical transmission.
Life Cycle: Reduviid (multiplies)-> Enters host-> Trypomastigote in blood-> Amastigote (multiplies) in muscle & nerve-> Trypomastigote in blood
Diagnoses: Thin smear, Thick smear, Fresh smear, Xenodiagnosis (Trypomastigote levels not high in blood, multiplies in bug as well).
Symptoms & Pathology: Acute (4-8w): Bites near eye & mouth causing legions called Chagoma (Romana's Sign) that last for months, Fever, Progressive anemia, Edema, Lymphadenopathy, Hepatosplenomegaly, EKG abnormalities, CNS involvement, Degeneration of parasitized tissue. Intermediate: Asymptomatic Chronic (Fatal): Fever, Constipation & Abdominal Distension (Myenteric plexus destruction), EKG abnormalities, Cardiomegaly & apical aneurysms (destruction of myocardial figers & ganglion cells), Pain.
Treatment: Benzimidazole & Nifurtimox (Older drug): Both treat all symptoms including neurological ones. No effective drug in chronic state - supportive therapy only.
Control: Education, Improve housing, Vector control, Screening of blood donors.

Front 2

Trypanosoma Rangeli (Protozoa) "American Trypanosomiasis (Chagas)"

Back 2

Hosts: Possum, Armadillo, Rodents, Humans
Location: South & Central America
Transfer: Same as Trypanosoma cruzi.
Life Cycle:
Diagnoses: Same as Trypanosoma cruzi.
Symptoms & Pathology: Apathogenic
Treatment: Benzimidazole: All symptoms including neurological ones. Nifurtimox: Older drug.
Control: Same as Trypanosoma cruzi.

Front 3

Trypanosoma brucei gambiense (Protozoa) "African Trypanosomiasis"

Back 3

Hosts: Humans & Pigs main reservoirs of infection
Location: West Africa
Transfer: Riverine Tsetse flies: Through saliva. Feed during day. Bite behind ears is extremely painful. Vertical transmission.
Life Cycle: All stages occur in blood.
Diagnoses: Thin smear, Thick smear, Aspirated gland juice, CSF (Centrifuged deposit), PCR/DNA.
Symptoms & Pathology: May initially be Asymptomatic (chronic). Trypanosoamil chancre (bite), Enlarged cervical lymph nodes (Winterbottom's Sign), Intermittent fever (1-2yr), Progressive weakness, anemia & wasting, CNS invasion (leads to coma) [takes months].
Treatment: Intravenous Suramin: Removes tryps everywhere but CNS. Melarsoprol: CNS treatment.
Control: Aerial, ground, & cattle insecticide. Biconical trap for fly.

Front 4

Trypanosoma brucei rhodesiense (Protozoa) "African Trypanosomiasis - Rhodesian Sleeping Sickness"

Back 4

Hosts: Gaming & Domestic animals, Humans
Location: Central & East Africa
Transfer: Savannah Tsetse flies: Through saliva. Feed during day. Bite behind ears is extremely painful. Vertical transmission.
Life Cycle: All stages occur in blood.
Diagnoses: Thin smear, Thick smear, Aspirated gland juice, CSF (Centrifuged deposit), PCR/DNA.
Symptoms & Pathology: Usually acute symptoms. Trypanosoamil chancre (bite), Enlarged cervical lymph nodes (Winterbottom's Sign), Intermittent fever (3-6mo), Progressive weakness, anemia & wasting, CNS invasion (leads to coma) [takes weeks].
Treatment: Intravenous Suramin: Removes tryps everywhere but CNS. Melarsoprol: CNS treatment.
Control: Aerial, ground, & cattle insecticide. Biconical trap for fly.

Front 5

Leishmania donovani (Protozoa)

Back 5

Hosts: Canids (dogs, etc.), Rodents (rarely), Humans.
Location: East India, Africa, South Europe, South & Central America.
Transfer: Phlebotomus & Lutzomyia (sandfly): "Socked" blood suckers that bite @ dusk & dawn (don't need water for procreation). Dry climates. Live in termite hills.
Life Cycle: Amastigote in visceral WBC's 4-6 days after infection. Promastigote in saliva of the fly. Multiplies in vector & host.
Diagnoses: Amastigote in marrow/spleen smears, Culture of aspirates / blood taken during febrile period, Xenodiagnosis, Serology.
Symptoms & Pathology: Early: Irregular fever (double daily peak), Anemia, Leucopenia, Diarrhea, Bleeding gums, Joint pain, Weight Loss. Late: Enlarged lymph nodes, Splenomegaly, Hepatomegaly. Infection reappears after treatment in immunocompromised individuals.
Treatment: Pentavalent antimonials by IV (Pentostam - original). Amphotericin B - new & better but expensive.
Control: Human vector barrier, Control of vector & reservoirs (flea collars), Immunization.

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Leishmania tropica (Protozoa)

Back 6

Hosts: Canids (dogs, etc.), Rodents (rarely), Humans.
Location: East India, Africa, Southern Europe.
Transfer: Phlebotomus (sandfly): "Socked" blood suckers that bite @ dusk & dawn (don't need water for procreation). Dry climates. Live in termite hills.
Life Cycle: Amastigote in skin macrophages (WBC's). Promastigote in saliva of the fly. Multiplies in vector & host.
Diagnoses: History, Amastigote in fluid aspirated (culture) from below ulcer, Serological (limited value).
Symptoms & Pathology: Small red papule that ulcerates after 2-4 months. Dry ulcer that will heal in 2-3 months in immunocompetent individuals.
Treatment: Pentavalent antimony compounds by IV (Pentostam - original). Amphotericin B - new & better but expensive.
Control:

Front 7

Leishmania major (Protozoa)

Back 7

Hosts: Canids (dogs, etc.), Rodents (rarely), Humans.
Location: East India, Africa, Southern Europe.
Transfer: Same as tropica
Life Cycle: Amastigote in skin macrophages (WBC's). Promastigote in saliva of the fly. Multiplies in vector & host.
Diagnoses: History, Amastigote in fluid aspirated (culture) from below ulcer, Serological (limited value).
Symptoms & Pathology: Small red papule that ulcerates after 2 weeks. Produces serous exudate. Heals on its own in immunocompetent individuals.
Treatment: Pentavalent antimonials by IV (Pentostam - original). Amphotericin B - new & better but expensive.
Control:

Front 8

Leishmania braziliensis (Protozoa)

Back 8

Hosts: Dogs (main reservoir), Humans.
Location: South & Central America.
Transfer: Lutzomyia (sandfly): "Socked" blood suckers that bite @ dusk & dawn (don't need water for procreation). Dry climates.
Life Cycle: Amastigote in skin macrophages (WBC's). Promastigote in saliva of the fly. Multiplies in vector & host.
Diagnoses: (Direct Only) Amastigote in legions, Culture/lab animals.
Symptoms & Pathology: Small cutaneous papule. Ulcerates & heals after few months. After 3-20 years, destructive oral &/or nasal legions (Espunda or Uta [mucocutaneous leishmaniasis]).
Treatment: Pentavalent antimonials by IV (Pentostam - original). Amphotericin B - new & better but expensive.
Control: Human vector barrier, Control of vector & reservoirs (flea collars), Immunization.

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Leishmania guyanesis (Protozoa)

Back 9

Hosts: Sloth & Rodents (main reservoir), Humans.
Location: South & Central America.
Transfer: Same as braziliensis
Life Cycle: Amastigote in skin macrophages (WBC's). Promastigote in saliva of the fly. Multiplies in vector & host.
Diagnoses: (Direct Only) Amastigotes in legions, Culture/lab animals.
Symptoms & Pathology: Small cutaneous papule. Ulcerates & heals after few months. After 3-20 years, destructive oral &/or nasal legions (Espunda or Uta [mucocutaneous leishmaniasis]).
Treatment: Pentavalent antimonials by IV (Pentostam - original). Amphotericin B - new & better but expensive.
Control:

Front 10

Trichomonas vaginalis (Protozoa)

Back 10

Hosts: Humans
Location: Worldwide
Transfer: Sexual intercourse
Life Cycle: Binary fission in: female-Vagina. male-Urethra, Epididymis, & Prostate. No protective stage.
Diagnoses: Trophozoites in urine or vaginal discharge smears.
Symptoms & Pathology: Males: Asymptomatic. Females: Vaginitis, burning sensation, thick yellow discharge, vulvar &/or vaginal erythema.
Treatment: Metronidazole (Flagyl) - sexual partners treated simultaneously.
Control:

Front 11

Giardia lamblia (Protozoa)

Back 11

Hosts: Humans, Dogs, Cattle, Sheep, Wild mammals e.g. Beavers.
Location: Worldwide
Transfer: Ingestion of cysts. Trophozoites passed in diarrhea noninfective. Cysts passed in dry stools are immediately infective.
Life Cycle: Trophozoites divides & lives in the intestines & sloughs off in feces in bursts. Diagnosis difficult because stool sample may not contain parasite.
Diagnoses: Symptoms, Stool microscopy, ELISA, Immunofluorescence (good but expensive), Therapeutic trial
Symptoms & Pathology: Any or All: Pale, loose, foul smelling, & fatty stools. Diarrhea 3-8 x daily. Abdominal distension. Offensive flatulence. Abdominal pain. Weight loss - anorexia. Sulphurous belching. Lasts for few days to several weeks.
Treatment: Metronidazole (Flagyl).
Control: Good hygiene, Boiling or filtering water, Cook veg, Prop sanitation, No human fertilizer.

Front 12

Cryptosporidium parvum (Protozoa)

Back 12

Hosts: Turkey, calf, lamb, kid, deer, foal, puppy, kitten, human.
Location: Worldwide
Transfer: Water, Food. Not killed by chlorine. Oocysts immediately infective by ingestion.
Life Cycle: Invades gut enterocytes (brush border of intestine). Release oocyst in feces with 4 sporozoites each.
Diagnoses: Oocysts in stool (mod Ziehl-Neelsen stain), ELISA, Immunofluorescence, Intestinal biopsy.
Symptoms & Pathology: 1-2 weeks after exposure: Explosive, watery diarrhea that is brown-green in color. Frequency 2-10 x day for 3-10 days, complete recovery. Immunocompromised: Chronic diarrhea, Abdominal pain, Fever, Lymphadenopathy, Weight loss, Malnutrition, Villous atrophy.
Treatment: Don't use anti-diarrheal b/c prolongs infection. Fluid & electrolyte loss treatment.
Control: Same as giardia.

Front 13

Entamoeba histolytica (Protozoa) Amoebiasis
(non-invasive form)

Back 13

Hosts: Humans ONLY (not zoonosis)
Location: Worldwide
Transfer: Feces -> (Fluids, Fingers, Flies, Fields) -> Food. Ingestion of cysts.
Life Cycle: Noninvasive: Trophozoites live in lumen of large intestine.
Diagnoses: Noninvasive: Cysts in stool
Symptoms & Pathology: Noninvasive: 95% Asymptomatic, Diarrhea, Flatulence, Abdominal pain, Blood & mucus in stool, Tear drop ulcers in gut.
Treatment: Metronidazole (Flagyl). Fluid & electrolyte loss treatment.
Control: Same as giardia.

Front 14

Entamoeba histolytica (Protozoa) Amoebiasis
(invasive form)

Back 14

Hosts: Humans ONLY (not zoonosis)
Location: Worldwide
Transfer: Trophozoites passed in diarrhea noninfective. Cysts passed in dry stools are immediately infective by ingestion.
Life Cycle: Invasive: Trophozoites in RBC's, Liver, & Other organs.
Diagnoses: Invasive: Trophozoites in RBC's, ELISA (expensive), Aspiration, Ultrasound (liver cyst), X-ray/CT/MRI (brain & lung cyst).
Symptoms & Pathology: Invasive/pathogenic [Trophozoids] 'strains' (5% of): Cysts in Liver (majority), Brain, Skin, Lungs, Orbit, Spleen, Genitals -> Fever, Tender liver (pain), Hepatomegaly.
Treatment: Metronidazole (Flagyl). Ultrasound guided drainage of cysts may be necessary.
Control:

Front 15

Toxoplasma gondii (Protozoa) Toxoplasmosis

Back 15

Hosts: Def: Cats. Inter: Lamb, Goat, Pork, Chicken, Rodents
Location: Worldwide
Transfer: Bradyzoites: Ingestion (meat, lamb, goat, pork). Oocysts: Cat feces sporulation takes 1-5 dy. Tachyzoites: Ingest raw milk & Vertical transmission.
Life Cycle: Cats ingest cysts (Bradyzoites)-> Trophozoites-> Schizogenous & gametogonous development-> Oocysts (3-10dy)-> Unsporulated Oocysts shed for 1-3wk-> Sporulate after 1-5dy in environment.
Diagnoses: IgG, IgM serology. Imaging for ocular Toxoplasmosis or toxoplasmic encephalitis, Isolation of parasites, Tissue biopsy.
Symptoms & Pathology: Immunocompetent: Usually Asymptomatic & get immunity (IgM during infection & IgG after). Immunocompromised: Invade all tissues but predilection sites Eye (Chorioretinitis), Brain (Cysts, encephalitis: Headache, Disorientation, Coma). Fetus of recently newly infected mother: Severe: Chorioretinitis, Hydrocephalus (aqueduct block), Cerebral Necrosis, Liver failure. Less Severe: Poor cognitive skills, Jaundice, Anemia, Convulsions, Growth retardation. Tachyzoites: Rapid proliferation & transport to all organs. Bradyzoites: Slow replication & persists indefinitely & can reactivate (dangerous for immunocompromised)
Treatment: Spiramycin - Prevent vertical transmission to fetus & may be given after birth as well. TMP/SMX (Bactrim) Pyrimethamine w/ Dapsone: Prophylaxis for immunocompromised individuals.
Control:

Front 16

Plasmodium falciparum (Protozoa)

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Hosts: Humans
Location: Hot & wet climates. Predominant in Africa, New Guinea, & Haiti. Also present in South America & Asia.
Transfer: Anopheline mosquito (saliva contains sporozoites) & feeds at night. Sporozoites in saliva mature from ingested gametocytes. Vertical transmission.
Life Cycle: Sporozoites ->Liver schizont(8d*40,000)->Merozoites-> RBC's->Trophozoites ->RBC schizont(36-48h*8-32)->Merozoites exit-> Gametocytes (mosq xfer) or Invade RBC's-> Gametocytes M&F fuse-> Zygote in mosq-> Ookinete-> Penetrate gut wall-> Oocyst-> Multiply-> Salivary gland-> Sporozoites (mosq 5d to mature).
Diagnoses: Thick blood (Malaria present? Sensitivity). Thin blood (Type? Specificity). Later regular fever pattern indicative (not as regular in falciparum b/c of RBC schizont release range).
Symptoms & Pathology: Pathogenesis: Haemolysis of RBC's. Parasite metabolites. Immune response. Cytoadherence (occlusion of capillaries-edema, organ failure) falciparum only. Cytokine increase. Malaria pigment production depletes iron stores increasing anemia. Clinical features (looks like flu initially): Cold stage(15-60m): Mild, inappropriate cold-> leads to violent whole body shaking. Skin dry, pale, & cold. Pulse rapid & low-volume. Hot stage(2-6h): Fever. Skin flushed, dry & burning. Pulse rapid & bounding. Sweating stage(2-4h): Fever breaks. Profuse drenching sweat after patient may feel better. Can cause Diarrhea. Cerebral malaria (falciparum only): Coma, Convulsions, Abnormal posturing, Dysconjugate gaze, Retinal hemorrhages
Treatment: Coartem, Artemether/lumefantrine. Quinine, Quinadine (IV form of Quinine): Used on chloroquine resistant strains only (reserve drug).
Control: Prophylactic drugs: Mefloquine, Doxycycline, Chloroquine, Malarone, Pauladrine. Bed nets impregnated with residual insecticide. Protective clothes, Repellent (DEET).

Front 17

Plasmodium vivax (Protozoa)

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Hosts: Humans
Location: Hot & wet climates. More common in S & C America, Asia.
Transfer: Anopheline mosquito (feeds at night). Vertical transmission.
Life Cycle: Same as falciparum but: Some liver schizonts become hypnozoites. RBC schizonts(48h*12-24).
Diagnoses: Thick blood smear to determine if malaria present. Thin blood smear to determine type.
Symptoms & Pathology: Same as plasmodium falciparum.
Treatment: Chloroquine: Kills blood stages. Primaquine: Kills hypnozoites in liver preventing relapse & recurrence.
Control: Same as plasmodium falciparum.

Front 18

Plasmodium ovale (Protozoa)

Back 18

Hosts: Humans
Location: Hot & wet climates. Widespread.
Transfer: Anopheline mosquito (feeds at night). Vertical transmission.
Life Cycle: Same as falciparum but: Some liver schizonts become hypnozoites. RBC schizonts(48h*4-16).
Diagnoses: Thick blood smear to determine if malaria present. Thin blood smear to determine type.
Symptoms & Pathology: Same as plasmodium falciparum.
Treatment: Chloroquine: Kills blood stages. Primaquine: Kills hypnozoites in liver preventing relapse & recurrence.
Control: Same as plasmodium falciparum.

Front 19

Plasmodium malariae (Protozoa)

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Hosts: Humans
Location: Hot & wet climates. Replaces P. vivax in West Africa. Worldwide
Transfer: Anopheline mosquito (feeds at night). Vertical transmission.
Life Cycle: Same as falciparum but: RBC schizonts(72h*6-12).
Diagnoses: Thick blood smear to determine if malaria present. Thin blood smear to determine type.
Symptoms & Pathology: Same as plasmodium falciparum.
Treatment: Chloroquine
Control: Same as plasmodium falciparum.

Front 20

Babesia (protozoa)

Back 20

Hosts:
Location:
Transfer: Ixodes tick
Life Cycle:
Diagnoses: Blood smear, no RBC pigment appears as "maltese cross"
Symptoms & Pathology: Fever & anemia
Treatment:
Control: Quinine, Clindamycin

Front 21

Naegleria (protozoa)

Back 21

Hosts:
Location:
Transfer: Swimming in freshwater lakes (enter via cribriform plate)
Life Cycle:
Diagnoses: Amebas in spinal fluid
Symptoms & Pathology: Rapidly fatal meningoencephalitis
Treatment:
Control: None

Front 22

Fasciola hepatica (Trematode)

Back 22

Hosts: Def: Humans, Sheep, Cattle. Inter: Snail, Grass
Location: S America, Europe, Africa, Australia, New Zealand
Transfer: Human defecates eggs-> Miracidia hatch in water-> Snail-> Release cercaria-> Grass-> Metacercariae-> Humans ingest
Life Cycle: Infects bile ducts.
Diagnoses: Eggs in feces.
Symptoms & Pathology: Young flukes (damage liver): Severe headache, Backache, Chills, Fever. Adult flukes (cause atrophy of portal vessels, hemorrhage, secondary pathological conditions that may be lethal): Enlarged tender/cirrhotic liver, Diarrhea, Anemia -> Indicate advanced infection
Treatment: Triclabendazole (Treatment). Anthelmintics (Drugs that expel helminths from body - Control)
Control: Decrease snail habitats & herbivore snail contact, Anthelmintics.

Front 23

Opisthorchis sinensis (Trematode). Aka "Clonorchis sinensis"

Back 23

Hosts: Def: Humans, Reptiles, Birds, Mammals incl. Dogs. Inter: Snail, Fish
Location: E. Asia, Japan
Transfer: Human defecates eggs-> Miracidia hatch in water-> Snail-> Release cercaria-> Fish-> Metacercaria-> Humans ingest
Life Cycle: Infects bile ducts.
Diagnoses: Eggs in feces??????
Symptoms & Pathology: Mechanical & toxic irritation of the bile ducts, especially with heavy infection (up to 6000 flukes). Can cause diarrhea. Usually asymptomatic.
Treatment: Praziquantel
Control: Prevent fecal contam of fish ponds, Decrease snail pop, Cook fish properly.

Front 24

Paragonimus westermani (Trematode)

Back 24

Hosts: Def: Humans, Cats, Dogs. Inter: Snail, Crustaceans
Location: E Asia, Parts W Africa, S & C America
Transfer: Human defecates eggs-> Miracidia hatch in water-> Snail-> Release cercaria-> Crustaceans-> Metacercaria-> Humans ingest
Life Cycle: Infects lung.
Diagnoses: Eggs in sputum or feces.
Symptoms & Pathology: Cough, Blood stained sputum.
Treatment: Praziquantel
Control:

Front 25

Schistosoma haematobium (Trematode)

Back 25

Hosts: Def: Humans. Inter: Bulinus (snail). Not zoonotic.
Location: Africa, Middle East, India
Transfer: Human urinate eggs-> Miracidia-> Bulinus snail (asexually reproduce)-> Cercaria-> Skin penetration-> Adults form eggs sexually
Life Cycle: Lives in blood vessels, prefers veins around urinary system.
Diagnoses: History, Eggs in urine, Cystoscopy, Gross haematuria (usual), Microhaematuria, Ultrasound-> morbidity assessment
Symptoms & Pathology: Clinical symptoms: Swimmer's itch (severe 0-3dy), Schistosomular pneumonitis (schistosomula migration 3-10dy), Acute schisto or Katayama Fever (onset egg laying->immune complex syndrome 3-8wk w/ eosinophilia) Chronic syndromes: Hydronephrosis, Thickened bladder wall (> 5mm) & polyps (up chance bladder cancer), Occlusion of ureters, Haematuria --> Anemia.
Treatment: Praziquantel. Acquired immunity later in life (reduce # eggs excreted)
Control: Kill parasite->reduce morbidity & trans, Molluscicides, Prevent contam, Protect from exposure.

Front 26

Schistosoma mansoni (Trematode)

Back 26

Hosts: Def: Humans, baboons. Inter: Biomphalaria (snail).
Location: Africa, Middle East, Eastern border of South America & Caribbean.
Transfer: Human defecate eggs-> Miracidia-> Biomphalaria snail (asexually reproduce)-> Cercaria-> Skin penetration-> Adults form eggs sexually
Life Cycle: Lives in blood vessels, prefers mesenteric veins.
Diagnoses: History, Eggs in stool or in rectal biopsy, Rectoscopy & microscopy of rectal snip, Ultrasound-> morbidity assessment
Symptoms & Pathology: Clinical symptoms: Swimmer's itch (severe 0-3dy), Schistosomular pneumonitis (schistosomula migration 3-10dy), Acute schisto or Katayama Fever (onset egg laying->immune complex syndrome 3-8wk w/ eosinophilia) Chronic syndromes: (Trapped ova calcify in vessels)--> Portal hypertension, Hepatomegaly, Hematemesis (ruptured esophageal varices->anemia), Splenomegaly, Melania (blood in feces).
Treatment: Praziquantel
Control: Same as Schistosoma haematobium.

Front 27

Schistosoma japonicum (Trematode)

Back 27

Hosts: Def: Humans, Oxen, Canines, Rodents. Inter: Oncomelania (snail)
Location: East Asia, Philippines
Transfer: Human defecate eggs-> Miracidia-> Oncomelania snail (asexually reproduce)-> Cercaria-> Skin penetration-> Adults form eggs sexually
Life Cycle: Lives in blood vessels, prefers mesenteric veins.
Diagnoses: History, Eggs in stool or in rectal biopsy, Rectoscopy & microscopy of rectal snip, Ultrasound-> morbidity assessment
Symptoms & Pathology: Clinical symptoms: Swimmer's itch (severe 0-3dy), Schistosomular pneumonitis (schistosomula migration 3-10dy), Acute schisto or Katayama Fever (onset egg laying->immune complex syndrome 3-8wk w/ eosinophilia) Chronic syndromes: (Trapped ova calcify in vessels)--> Portal hypertension, Hepatomegaly, Hematemesis (ruptured esophageal varices->anemia), Splenomegaly, Melania (blood in feces)
Treatment: Praziquantel
Control: Same as schistosoma haematobium.

Front 28

Taenia saginata (Cestode)

Back 28

Hosts: Def: Humans. Inter: Cow.
Location: Worldwide
Transfer: Ingest cyst in beef-> Tapeworm (small intestine)
Life Cycle: Humans defecate proglottids-> Release embryophore-> Cow ingest-> Oncosphere released-> Cysticercus in cow muscle
Diagnoses: Proglottids in feces.
Symptoms & Pathology: Usually asymptomatic but may be undesirable because proglottids released in feces & can also crawl out when not defecating.
Treatment: Tapeworm: Praziquantel.
Control: Education, Sanitation, Treatment, Meat inspec, Prop cook.

Front 29

Taenia solium (Cestode)

Back 29

Hosts: Def: Humans. Inter: Pork, Humans (eggs infect)
Location: Worldwide
Transfer: Ingest cyst in pork-> Tapeworm (small intestine). Ingest embryophore-> Cysticercosis with predilection sites in the brain & eye.
Life Cycle: Humans defecate proglottids-> Release embryophore-> Pig ingest-> Oncosphere released-> Cysticercus in pig muscle
Diagnoses: Proglottids in feces. Cysticercosis: Biopsy of sub Q nodules, calcified cysticercosis by x-ray & CAT scan, Serology
Symptoms & Pathology: Usually asymptomatic but may be undesirable because proglottids released in feces and can also crawl out when not defecating. Embryophore ingestion can cause body wide cysts: Neurocysticercosis: Headache, Visual hallucinations, Seizures, Coma. Ocular cysticercosis.
Treatment: Tapeworm: Niclosamide. Cysticercosis: Albendazole (newer & kills less aggressively). Corticosteroids (reduce inflam from dying parasite).
Control: Same as taenia saginata.

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Dipylidium caninum (Cestode)

Back 30

Hosts: Def: Dogs, Humans. Inter: Fleas & Lice
Location: Worldwide
Transfer: Humans infected by accidentally eating fleas from infected dogs.
Life Cycle: Tapeworm lives in small intestine.
Diagnoses: Proglottids in feces.
Symptoms & Pathology: Usually asymptomatic. May have: Abdominal pain, Diarrhea, Anal pruritus.
Treatment: Niclosamide or Praziquantel
Control:

Front 31

Echinococcus granulosus (Cestode) "Cystic Hydatid Disease"

Back 31

Hosts: Def: Dogs. Inter: Humans, Wild herbivore (Sheep)
Location: Worldwide
Transfer: Dog w/ tapeworm defecate egg-> Human/Animal eat egg-> Cysts-> Dogs eat cysts get tapeworm
Life Cycle: Def host: Live in small intestine. Inter host: Hydatid cysts in all organs w/ predilection sites in liver then lungs.
Diagnoses: Ultrasound is gold standard for locating hydatid cysts, CT, MRI, X-ray. ELISA.
Symptoms & Pathology: 85% of cases are subclinical. Can cause body wide cysts: Lung cysts (predilection): Symptomatic very quickly. Liver cysts (predilection): Symptoms longer to develop. Ocular Cystic Echinococcosis. Can result in anaphylaxis if echinococcal antigens are released from cysts.
Treatment: Surgical (not if cyst contact biliary tree): Puncture(cyst), Aspirate(parasites), Inject (alcohol), Reaspirate(fluid). Albendazole.
Control: Education, Control dog population, Treat dogs, Meat inspection.

Front 32

Echinococcus multilocularis (Cestode) "Alveolar Hydatid Disease"

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Hosts: Def: Dogs. Inter: Humans, Rodents
Location: Worldwide
Transfer: Dog w/ tapeworm defecate egg-> Human/Animal eat egg-> Cysts-> Dogs eat cysts get tapeworm
Life Cycle: Def host: Live in small intestine. Inter host: Hydatid cysts in all organs w/ predilection sites in liver then lungs.
Diagnoses: Ultrasound is gold standard for locating hydatid cysts, CT, MRI, X-ray. ELISA.
Symptoms & Pathology: 85% of cases are subclinical. Can cause body wide cysts: Lung cysts (predilection): Symptomatic very quickly. Liver cysts (predilection): Symptoms longer to develop.
Treatment: Albendazole for the life of the patient. Surgery not an option because of small size of cysts.
Control: Same as echinococcus granulosus.

Front 33

Diphyllobothrium latum (Cestode)

Back 33

Hosts: Def: Dogs, Cats, Bears, Humans. Inter: Fresh water flea->Fish
Location: Worldwide, but major in north hemisphere near fresh water lakes.
Transfer: Definitive host defecates eggs->fresh water flea->fresh water fish-> New host eats fish with parasite & develops tapeworm
Life Cycle: Adult worms live in small intestine.
Diagnoses: Detection of eggs in feces.
Symptoms & Pathology: May lead to megaloblastic anemia because tapeworm can outcompete the host for vitamin B12.
Treatment: Praziquantel. Treat anemia.
Control:

Front 34

Ancylostoma duodenale (Nematode) "Hookworm"

Back 34

Hosts: Def: Humans
Location: Africa, S & C America, Mid East, Orient, Philippines
Transfer: Human defecates egg-> Larva leaves egg before L1-> L1-L2(24-36h)-> L2-L3(1w) infective-> Skin penetration
Life Cycle: L3 larva infective (out of egg). Undergoes hepatic tracheal migration. Adults live in small intestine. Sexual repo.
Diagnoses: Salt floatation (eggs).
Symptoms & Pathology: Skin penetration (Ground itch). Larval migration to lungs-> Mild pneumonitis. Suck blood in intestines-> Anemia (Tiredness, Edema, Myalgia, Pallor, Breathlessness). May cause iron deficiency anemia (Hypochromic, Microcytic, Pigmented neutrophils, Many platelets).
Treatment: Albendazole: Kills worm. Treat anemia.
Control: Education (hygiene), Sanitation, Treatment

Front 35

Necator americanus (Nematode) "Hookworm"

Back 35

Hosts: Def: Humans
Location: Same as ancylostoma duodenale
Transfer: Same as ancylostoma duodenale
Life Cycle: Same as ancylostoma duodenale
Diagnoses: Salt floatation (eggs).
Symptoms & Pathology: Same as ancylostoma duodenale
Treatment: Albendazole: Kills worm. Treat anemia.
Control: Education (hygiene), Sanitation, Treatment

Front 36

Ascaris lumbricoides (Nematode)

Back 36

Hosts: Def: Humans
Location: Worldwide
Transfer: Human defecates egg-> L1-L2(3w) infective-> Ingestion of L2 larva still in egg.
Life Cycle: L2 larva infective (still in egg). Sexual repo. 200,000eggs/day. Larvae can produce other adults in environment.
Diagnoses: Salt flotation (eggs). Adult worms in diarrhea, out of mouth, nose, & ear.
Symptoms & Pathology: Loeffler's syndrome (pulmonary eosinophilia), Larvae fever, Cough, Wheeze, Rapidly changing X-ray picture. Adult worms: Biliary obstruction, Jaundice, Appendicitis, Pancreatitis, Asphyxia, Diarrhea.
Treatment: Albendazole
Control: Education (hygiene), Sanitation, Treatment

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Trichuris trichuria (Nematode) "Whipworm"

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Hosts: Def: Humans
Location: Worldwide but mostly in tropics
Transfer: Human defecates egg-> Maturation to L1(2w) infective-> Ingestion of L1 larva still in egg
Life Cycle: L1 larva is infective (still in egg). No HT migration. Adult lives in caecum. Sexual repo.
Diagnoses: Salt flotation (eggs).
Symptoms & Pathology: Most infections are asymptomatic. Heavy infection: Bloody diarrhea, Abdominal pain, Prolapsed of the rectum, Anemia, Impaired growth, Reduced cognitive function.
Treatment: Mebendazole
Control: Education (hygiene), Sanitation, Treatment

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Enterobius vermicularis (Nematode) "Pin worm"

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Hosts: Def: Humans
Location: Worldwide
Transfer: Females lay eggs-> L1-L3(4-6h) infective-> Ingestion of L3
Life Cycle: L3 larva infective. No HT migration. Adult lives in intestines. Female migrates to rectum to lays eggs & dies. Sexual repo.
Diagnoses: Itchy anus, especially @ night. Find eggs in stool (Graham slide).
Symptoms & Pathology: Itchy anus, especially at night.
Treatment: Albendazole (internet says Mebendazole)
Control:

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Strongyloides stercoralis (Nematode)

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Hosts: Def: Humans, Dogs.
Location: Worldwide, but more in concentrated in tropics.
Transfer: Human defecates L1 larva-> L3 infective-> Skin penetration. Autoinfection (can maintain > 30years).
Life Cycle: L3 larva infective. Undergoes hepatic tracheal migration. Sexual repo (does not follow 1 egg-> 1 adult rule for nematodes). Produce 5 eggs/day.
Diagnoses: Stool microscopy & culture (female doesn't produce many larvae), ELISA, Eosinophilia, Larva currens.
Symptoms & Pathology: Early: Itchy eruption at site of penetration, Cough & wheeze, Upper abdominal pain & diarrhea, Weight loss, Larva currens. Established infection: Intestinal symptoms, Flattening of villi, Malabsorption, Smelly yellow stool, Diarrhea, Larva currens.
Treatment: Thiabendazole
Control: Difficult because it is a zoonosis.

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Ancylostoma caninum (Nematode)

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Hosts: Def: Dogs. Inter: Humans
Location: Worldwide
Transfer: Skin penetration by L3. Require humid & moist soil.
Life Cycle: L3 larva penetrate skin but can't migrate any farther. Some make it to intestines but don't produce eggs. Sexual repo.
Diagnoses: Cutaneous larva migrans
Symptoms & Pathology: Cutaneous larva migrans (feet), Intense pruritus, Secondary infections, Eosinophilic enteritis when some L3 make it to intestines but they do not produce eggs.
Treatment: Thiabendazole
Control:

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Ancylostoma braziliense (Nematode)

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Hosts: Def: Cats. Inter: Humans
Location: Worldwide
Transfer: Skin penetration by L3. Require humid & moist soil.
Life Cycle: Same as ancylostoma caninum.
Diagnoses: Cutaneous larva migrans
Symptoms & Pathology: Cutaneous larva migrans (feet), Intense pruritus, Secondary infections, Eosinophilic enteritis when some L3 make it to intestines but they do not produce eggs.
Treatment: Thiabendazole
Control:

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Toxocara canis (Nematode)

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Hosts: Def: Dogs (puppies main excretor) Inter: Humans.
Location: Everywhere in tropics and southern U.S.
Transfer: Dogs defecate egg (usually start 3w after birth)-> L1-L2(2w) infective-> Ingestion of L2 larva still in egg.
Life Cycle: L2 larva infective. Migrates to eye & liver in humans. Does not lay eggs in humans. Sexual repo.
Diagnoses: History, Symptoms, Serology.
Symptoms & Pathology: Ocular larva migrans (OLM) cause blindness. Visceral larva migrans (VLM) cause hepatomegaly.
Treatment: Thiabendazole??????????
Control: Deworm dogs. Properly control dog feces.

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Trichinella spiralis

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Hosts: Def: Domestic pigs & horses, Rats. Inter: Humans.
Location: N & S America, Europe
Transfer: Ingestion of L1 larva in meat.
Life Cycle: L1 is infective stage. Larvae live in striated muscle. Adult in small intestine of def host. In humans few larva mature to adulthood, many remain larva. Sexual repo.
Diagnoses: ELISA, Muscle biopsy (Microscopy or Rapid PCR)
Symptoms & Pathology: Enteric phase (usually mild): Nausea, Vomiting, Colic, Diarrhea, Sweating. Migratory (invasive) phase: Periorbital edema, Eosinophilia (large infection), Myalgia, Fever. Encystment Phase: Myalgia, Edema, Dehydration, Fever, (Usually subsides 2mo after infection), Eosinophilia (subsides but stays elevated).
Treatment: Mebendazole (kills larvae off very slowly)
Control: Education, Prop meat cooking, Meat inspec, Freeze meat, Rat free piggeries

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Trichinella nelsoni

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Hosts: Def: Hyenas, warthogs, & other carnivores. Inter: Humans.
Location: Sub-Saharan Africa
Transfer: Same as spiralis
Life Cycle: Same as spiralis
Diagnoses: Same as spiralis
Symptoms & Pathology: Same as spiralis
Treatment: Same as spiralis
Control: Same as trichinella spiralis.

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Trhichinella nativa

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Hosts: Def: Polar bears, arctic foxes, bears. Inter: Humans.
Location: Arctic circle
Transfer: Same as spiralis
Life Cycle: Same as spiralis
Diagnoses: Same as spiralis
Symptoms & Pathology: Same as spiralis
Treatment: Same as spiralis
Control: Same as trichinella spiralis but Freezing does NOT kill parasite.

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Loa Loa (Nematode-Human Subcutaneous Filaria)

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Hosts: Def: Humans. Inter: Chrysops fly
Location: Rain forests of Africa
Transfer: L3 larva (infective) inoculated by chrysops fly (day biter)
Life Cycle: L1 larva (MF) released into blood by adult diurnally. L1-L3 in Chrysops fly (no multiplication). Sexual repo.
Diagnoses: Calabar swellings. Patients can see worms in eyes.
Symptoms & Pathology: Calabar swellings (Pain) caused by worm migration. Patient can see worm crawling in front of eyes. Swelling on the back of the arms.
Treatment: Ivermectin. Surgical removal of worms.
Control:

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Dracunculus medinensis (Nematode-Human Subcutaneous Filaria) "Guinea worm"

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Hosts: Def: Humans. Inter: Cyclops water flea (microscopic)
Location: Central Africa (esp. Sudan), India, Bangledesh
Transfer: L3 larva (infective) inoculated by drinking cyclops flea.
Life Cycle: L1 larva (MF) released into water by adult. L1-L3 in flea (no multiplication). PPP of 1 year. Worms mature at harvest time. Sexual repo.
Diagnoses: Foot pain & ulcers with worm visible.
Symptoms & Pathology: Migration of female to foot cause intense pain (relieved by water immersion), Ulcer, Secondary bacterial infection, Disability. Dead worm-> cellulitis.
Treatment: Albendazole, Thiabendazole, Moist bandages (don’t' kill, make easier to remove). Removed by slowly winding around stick.
Control: Clean water (filters). Abate kills cyclops. Infected no enter water.

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Onchocerca volvuls (Nematode-Human Subcutaneous Filaria) "River Blindness"

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Hosts: Def: Humans. Inter: Simulium fly
Location: Central Africa. North part of South America, C America (near flowing rivers)
Transfer: L3 larva (infective) inoculated into skin (slashing that enters subQ tissue but does not cause bleeding) by Simulium fly.
Life Cycle: L1 larva (MF) in skin. L1-L3 in simulium fly (no multiplication). Adult in onchocerc-omata (near bone). MF contain Wolbachia [gram(-) bacteria]-> need to survive & main cause of inflam. Sexual repo.
Diagnoses: Skin snips, ELISA plate.
Symptoms & Pathology: Adult worms: Little pathology. Some onchocercomata visible over bony prominences. Microfilariae in skin: Pruritus (itch never stops), Papular dermatitis, Lichenification (lizard skin), Depigmentation, Dermal atrophy (tissue-paper skin)-> Hanging groin, Sclerosing keratitis-> progressive blindness. Dying MF: Allergic reaction.
Treatment: Ivermectin. Surgical removal of worms. Doxycycline.
Control: Vector control, Treatment, Relocation of villages.

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Wuchereria bancrofti (Nematode-Human Lymphatic Filaria)

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Hosts: Def: Humans. Inter: Mosquitoes.
Location: Africa, Middle East, Asia, Philippines
Transfer: L3 larva (infective) inoculated by mosquito. Anopholine & Mansonia (rural). Culex (urban)
Life Cycle: L1 larva (MF) in blood (@ night). L1-L3 in mosquito (10dy-no multiplication). PPP of 13mo. Adults initially in lymph & migrate to nodes causing damage. Predilection site in males (spermatic cord). Sexual repo.
Diagnoses: ICT card test (Gold standard-detect female worm antigens), Thick blood film, Membrane filter concentration.
Symptoms & Pathology: Usually contracted in childhood->manifest later. Adult worms: Lymphatic damage-> Lymphoedema-> Recurrent infection-> Elephantiasis & Hydrocoele (men) & Chyluria (early). Micro Filaria: Filarial fever (secondary infections->acute inflammatory episodes)
Treatment: Micro Filaria (DEC clears 95% up to 1yr, Ivermectin & Albendazole 99% up to 1yr). Hydrocoele (Surgery). Lymphoedema/Elephantiasis (Hygiene, Elevation, Skin care, Exercise)
Control: Guyana/China DEC fortified salt. Mass drug administration. Doxycycline (new->kills wolbachia->kills MF)