Protozoa Taxonomy by mikesanye

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									                  Morphology/Transmission      Epidemiology                  Diseases                             Diagnoses              Diagnosis/Treatment
Protozoans:
Entamoeba          Motile trophozoite in LI    2 morphologically            Most are symptomatic                Stool exam –          Tissues– metronidazole
Histolytica       Has pseudopods               identical species – E.                                             tropho’s and cysts
                                               histolytica and E. dispar      Intestinal Amebiasis (dysentery)                           Lumenal agent – second
                   Cyst is round                                             Extraintestinal – Liver Abscess     Find tropho’s or     drug active against cysts
                                                Distribution is in warmer                                        cysts in biopsy of
                   Asexual reproduction       climates with poor             Can have Pleural, Lung, or         tissue                  Have to tx both tissue and
                                               sanitation                    Pericardial Involvement                                     lumenal form
                                                                                                                   Serology
                  Transmission:
                   Fecal-oral
                   Food/water-borne
Freeliving                                                                    Keratoconjunctivitis - assoc w/
amebas:                                                                      contact lenses)
Naeglaria,                                                                    Amebic meningoencephalitis -
Acanthema,                                                                   after freshwater exposure
Balamuthia                                                                    Granulomatous amebic
                                                                             encephalitis – in IC hosts

Trichomonas        Pear-shaped trophozoites                                  Vaginitis                           Direct microscopy-    Metronidazole
Vaginalis         with motile flagella                                        Nongonococcal urethritis           Pear-shaped
                                                                                                                  trophozoites with       Sexual partners should be
                  Transmission:                                                                                   motile flagella        treated
                   Sexual Contact

Giardia Lamblia    Flagellated trophozoite     Worldwide in water           Giardiosis                          Stool exam            Metronidazole
                   Pear-shaped                 Epidemics related to          Foul smelling water diarrhea
                   Two nuclei                 contaminated fresh water        Greasy stools                       Aspirate small        Furazolidine is available
                   Suction disc on lower       Common in day care            Malabsorption                      bowel                   Paramomycin can be used
                  surface for attachment to    centers                                                                                   to tx pregnant women
                  intestinal mucosa             Common in homosexual                                              String test
                                               men
                   Cysts are oval              Cysts resist chlorination                                         Test for Giardia
                   Formed in GI tract and                                                                        antigen in stool
                  passed to the stool

                  Transmission:
                   Fecal-oral
                   Food/water
Kinetoplastida:       Protozoans with single         Kinetoplast = specialized
                     flagellum                       mitochondria, composed of
                                                     nets of circular DNA
                      Amastigote inside host cell
                      Promastigote
                      Epimastigote
                      Trypomastigote


Trypanosoma           Multiply as amastigotes        Found t/out Latin America     Chagas disease:                   Serology                Tx not very good
cruzi                inside cell                      Reduviid bugs are infected     Acute phase                     Blood smear             Nifurtimox and
                                                     with blood meals                  Asymptomatic or Febrile                                 Benzidazole – may not be
                     Transmission:                    Reduviid bug bits person                                        Culture and PCR        helpful if chronic
                      Reduviid bug                   bug defecates and              Chronic form
                      Transfusions                  excretes parasites with feces     May remain asymp for decades
                                                                                       Cardiomyopathy                                           Prevention:
                                                      Affects:                        Megaesophagus and Megacolon                               Improved housing
                                                      Macrophages                                                                                Residual insecticides
                                                      Muscle cells                                                                               Screen blood
                                                      Autonomic ganglion in gut

                                                      Transfusion-transmitted
                                                     cases common in endemic
                                                     areas if not screened

T. brucei             Tryptomastigotes                                              African Trypanosomiasis
gambiensi and T.       In bloodstream, motile
brucei rhodesiense
                     Transmission:
                      Tsetse fly
Leishmania            Amastigotes found only         Reservoir = rodents            Old world cutaneous             Biopsy of inf tissue    Pentavalent antimonials
tropica complex      with macrophages                 Infections peridomestic       leishmaniasis                    – demonstrate             Amphotericin B
                                                                                                                      intracellular
                     Transmission:                    Semiarid regions of                                            amastigotes               Resistance cases – add
                      Sandfly bites                 middle east and Africa                                                                    allopurinol or analogues,
                                                                                                                       Culture                interferon gamma,
                                                                                                                       Serology useful in     paramomycin
                                                                                                                      visceral dz
L. mexicana           Amastigotes found only         Reservoir = forest rodents     New world cutaneous             Same as above           Same as above
complex              with macrophages                                                leishmaniasis
                                                      From Argentina to Texas
                     Transmission:
                      Forest zoonoses
                      Dz when man enters forest
L. braziliensis    Amastigotes found only        Reservoirs = arboreal          New world cutaneous             Same as above         Same as above
complex           with macrophages               animals                         leishmaniasis
                                                                                  Mucocutaneous leishmaniasis

L. donovani        Amastigotes found only        Reservoir = man, dogs          Visceral leishmaniasis          Same as above         Same as above
complex           with macrophages
                                                  Foci in India,
                                                 Mediterranean, East Africa,
                                                 and Latin America

Sporozoa:          Apical complex
                   Sexual and asexual repro

 Plasmodium      Life cycle:                    Life cycle cont:                 Malaria                        Thin and thick blood
vivax              Sporozoites migrate t/        Some of merozoites form         Rupture RBC  cytokines        films:
 Plasmodium      bloodstream  liver            macro/micro-gametocytes           RBC destruction                 Ring forms in RBC
ovale              Replicates asexually in       transmit infection to                                           Gametocyte round
 Plasmodium      liver  releases merozoites    mosquitoes                       Hemolytic anemia
malariae          (tissue form, pre-RBC stage)    Sexual repro occurs w/in       Cerebral Malaria               Prevention:
                                                 mosquito                         Renal Failure                   Long sleeves, bed-
                   Merozoites invade RBCs                                        Pulmonary Failure              netting, insect
                                                  Endemic in most of world       Hypoglycemia                   repellents,
                   Inside RBC’s (RBC form)       Occasional cases in                                            permethrin-
                  Ring forms  trophozoites      Houston                                                          impregnated clothing
                   schizonts  schizont
                  ruptures and releases           Vivax and Ovale –                                               Chemoprophylaxis
                  merozoites                     reservoir of parasites                                           – cloroquine,
                                                 (hypozoite) in liver                                             mefloguine
                   Goes to brain, lung, and
                  kidney                          Malariae – no persistent
                                                 liver stage; low level
                                                 asymptomatic repro can
                                                 occur in RBC

 Plasmodium      Transmission:                   No persistent hepatic stage    Same as above                  Thin and thick blood
falciparum         Female anopheles mosquito                                     Causes localized sludging of   films:
                   Transfusion                                                  blood flow  tissue hypoxia       Ring forms
                   IV drug use                                                                                    Banana-shaped
                   Congenital                                                                                    gametocytes
                   Infection                                                                                      2 chromatid dots
                                                                                                                   Multiple org’s in
                                                                                                                  one RBC
                                                                                                                   More than 1% of
                                                                                                                  cell infected
Toxoplasma        Trophozoite                                                      Human infection usually     Serology              Normal hosts – no tx
gondii             Oval, crescent shaped                                         asymptomatic                                         Need tx:
                                                                                                                CT or MRI (AIDS        IC hosts
                  Tissue cyst                                                     Toxoplasmosis:               pts)                     Preg women
                   Contains intracystic                                           Acute Infection                                     Newborns
                  organism called bradyzoites                                       Asymptomatic
                                                                                    Lymphadenopathy                                    Pyrimethamine and
                  Bradyzoite                                                       Congenital toxoplasmosis                          sulfadiazine
                   Oval or round                                                  Reactivation infection                            Pyrimethamine and
                                                                                    Encephalitis                                      clindamycin
                  Oocyst                                                            CNS mass lesion
                   In which sporozoites are                                                                                          Prevention:
                  formed                                                                                                               Adequate cooking and
                                                                                                                                      freezing of meats
                  Transmission:                                                                                                        Avoid contact with cat
                   Cats                                                                                                              feces
                   Eating undercooked meats                                                                                           Trimethoprim/sulfa may
                   Transplacental                                                                                                    decr disease in AIDS pts

Cryptosporidium    Oocysts in stool                Common vet pathogen           Diarrhea                    Stool exam            Fluid/lytes replacement
parvum             Mature oocysts contain          US – most surface water is    Chronic diarrhea                                   Nutrition
                  sporozoites                      contaminated                    Biliary tract disease       Acid-fast stain       Reversal of immunosup.
                   Sporozoites attach to small     Many cities have comtam
                  intestine                        water supplies                                               Direct fluorescent    Paromomycin
                   Complete life cycle in epith                                                               antibody test w/        Azithromycin
                  cells along the lumenal          High risk groups:                                           monoclonal a-b
                  surface                           Day cares                                                                        Prevention:
                                                    Household contact                                                                 Good hygiene
                  Transmission:                     Health-care workers                                                               Avoid unfiltered water
                   Fecal-oral                      Travelers                                                                         Boiling will disinfect H2O
                   Contaminated water              Pts with AIDS
                                                    Waterborn epidemics
                                                   (Milwaulkee)

Isospora                                            Cyclospora associated         Diarrhea                    Stool exam            Trimethoprim-
Cyclospora                                         with outbreaks caused by         Constitutional symptoms     Acid fast            sulfamethoxazole
                                                   raspberries from Guatemala       Persist beyond 2 weeks      Autoflouresce
                                                                                                               under fluorescent
                                                    Isospora may cause                                        microscopy
                                                   eosinophilia
Microsporidia:       Intracellular pathogens        Pathogens in many animal                                        Stool exam
Enterocytozoon       Transmitted as spores         species                                                           Modified trichrome
Encephalitozoon      Spores have coiled polar                                                                       stain
Nosema              filament that injects                                                                             Non-specific
                    infectious material into host                                                                    florescent stains
                    cells

Enterocytozoon       Same as above                                                Chronic diarrhea, wasting in
                                                                                  AIDS
Encephalitozoon      Same as above                                                Chronic diarrhea, wasting in
                                                                                  AIDS
                                                                                   Biliary tract disease

Encephalitozoon      Same as above                                                Keratoconjunctivitis
and Nosema                                                                         Disseminated disease




                    Life cycle                                                Diseases                       Diagnoses                      Treatment
Trematodes –         Blind gut                                                                                                              Nearly all can be tx with
Flukes               Most hermaphroditic                                                                                                   praziquantel

Paragonimus          Lung fluke                                               Cough
                                                                               Lung nodule
                                                                               Hemoptysis
Fasicola hepatica    Liver fluke                                              Asymptomatic
                                                                               May have pain
Chlonorchis          Liver fluke                                              Asypmptomatic
sinensis                                                                       Pain
                                                                               Cholangitis
                                                                               Cholangocarcinoma
Schistosome          Adult worms live in mesenteric or vesicular venules      Schistosome dermatitis        Stool exam for eggs           Praziquantel orally in one
S. mansoni           Eggs migrate t/ bowel or bladder  excreted              Acute schistosomasasis        Urine and biopsy specimens   day administration
S. japonicum         Exposed to fresh water  eggs hatch  infect snail      Chronic schistosomiasis       Serology in acute dz
S. hematobium       exits snail  penetrates human skin                        Dysuria

                     Allergic rxn when schistosome penetrates skin
                     Goes to portal veins and veins draining urinary tract
                     Matures and produces eggs in veins
                     Granuloma formation around eggs
Cestodes          Adult stage
 Tapeworms        Intestinal
 Echinococcus     Segments = proglottids
                   Scolex
                  Larval stage – forms cysts in tissues

Tapeworms         Cyst form in tissues                                      Asymptomatic                  Stool exam - eggs        Praziquantel
                  Tapeworm (proglottids) in intestinal lumen                Minor abdominal sx’s
                  Adult worm attaches to SI mucosa via scolex               D. latum can directly
                  Grows by developing multiple proglottids                 absorb vitamin B12
                  Proglottids are shed in stool and release the eggs

                 Beef      T. saginata
                 Pork      T. solium
                 Fish      Diphylobrothrium latum
                 Dog/cat   Dipyllidium

                 Transmission:
                  Ingest infected meat
                  D. latum has been transmitted by pickled fish dishes

Tapeworm –        Intermediate host = pig                                   Cysticerosis                  CT or MRI                 Parenchymal dz –
Taenia solium     Pig is infected by ingesting eggs/proglottids in human    Neurocysticercosis            Western blot             anticonvulsant
                 feces                                                                                                                 Praziquantel and
                  Eggs hatch  larvae travel to tissues (animal muscle      Most common cause of                                    albendaxole can kill cysts
                 or human CNS)  Forms cysts                                adult onset seizures in the                               faster
                  Turns off host inflammatory response                     world                                                      Shunting operations or
                                                                                                                                      cyst removal for
                  Cyst form in muscle                                                                                                hydrocephalus
                  Tapeworm in intestinal lumen

Echiococcus       Dogs/wild canines host adult worms                        Cystic hydatid disease        CT, Ultrasound            Surgical removal with pre
                  Sheep/cattle/rodents eat feces  infected                  Mass lesion in liver          Serology tests           and post chemotherapy
                  Humans in contact w/ dog feces  infected  hosts          Mass lesion in lungs
                 for gradually enlarging cyst, the hydatid                                                  Aspiration may lead to    Albendazole
                  Cysts contain germinating structures, that form new       Alveolar hydatid disease     rupture                     Mebendazole
                 larvae                                                       Expanding infiltrative
                  Adult worm has three proglottids                           process, most in liver

                 Common in sheep-raising areas:                              Cyst rupture  anaphylaxis
                  Australia, New Zealand, Europe, Middle East, parts of    or metastatic lesions
                 Latin America
Intestinal and Tissue Nematodes:

                      Life cycle                                              Diseases                                    Diagnoses                 Treatment
Pinworm -             Transmission:                                            Anal pruritus                              Scotch tape              Mebendazole
Enterobius             Ingestion of eggs                                                                                 collection of eggs
vermicularis                                                                                                              from perianal area         Tx entire family
                       Eggs deposited in perianal area by migrating female
                      worms                                                                                                Not detected by stool
                       Adult worms live in large intestine                                                               examination

                       Most common in children

Whipworm –             Trans = ingestion of eggs                              Asymptomatic                               Stool exam – eggs        Mebendazole
Trichuris trichuria    Eggs passed w/ stools                                  Colitis w/ bloody diarrhea and rectal
                                                                              prolapse – in severe infections
                       Children most often affected
Ascaris                Trans = ingestion of eggs                              Asymptomatic                               Stool exam – eggs        Mebendazole
lumbricoides           Eggs deposited in perianal area by migrating female    Intestinal perforations or obstructions
                      worms                                                   – heavy infections
                       Adult worms live in small intestine

                       Children most often affected

Hookworms –            Trans = penetration of intact skin by larvae           Iron deficiency anemia – heavy             Stool exam – eggs        Mebendazole
 Necator                                                                     infections
americanus             Eggs are deposited w/ stools in environment 
 Ancylostoma         hatch  infective larvae                                 One of leading causes of anemia in
duodenale              Adult worms reside in small intestine                 the developing world

                       Each worm bites 3-6 villi per day and sucks blood

Strongyloides          Trans = penetration of intact skin by larvae           Asymptomatic                               Stool exam - larvae      Thiabendazole
stercoralis                                                                                                                Serology
                       Larvae passed w/ stools                               Hyperinfection/Dissemination                                           Disseminated infection
                       Adult worms live in small intestine                   When pt is given corticosteroids or are                               hard to tx
                                                                              IC – large numbers of worms invade
                       Autoinfection                                         entire organism
                                                                               Sepsis
                                                                               Pneumonia
                                                                               Meningitis
Toxocara Canis     Trans = ingestion of eggs of dog and cat Ascaris     Depends on location of lesions         Liver biopsy – see    Corticosteroids
                   Larvae migrate to:                                                                          larvae in granulomas
                    Liver, Brain, Eye, Other tissues
                   Cause granulomas
                   Allergic sensitization is part of pathogenesis
Trichinella        Trans = eating uncooked meat w/ cysts                Myalgia and allergic reactions with    Muscle biopsy         Corticosteroids if allergic
Spiralis                                                                fever 7-15 days after ingestion          Serology             rxn severe
                   Larvae liberate in intestine  mature to adults 
                  new larvae are produced                               Severe eosinophilia                                            Mebendazole may cause
                   New larvae goes to muscle  myositis                                                                               more severe sensitization

Filiarasis
 W. bancrofti
 B. malayi
 O. volvulus
 Loa loa

 Wuchereria       Trans = mosquitoes                                   Filarial fevers                        Blood smear for
brancrofti         Adults live in lymph nodes; causes obstruction       Elephantiasis                         microfiliariae
 Brugia malayi    Microfiliariae circulate in blood

Onchocerca         Trans = black fly                                    Dermatitis                             Skin biopsy –
volvulus           Adult worms live in cutaneous nodules                Blindness                             identify larvae
                   Microfilariae migrate in skin and eye

Loa Loa            Trans = large fly                                    Calabar swellings when they release    Blood smear –
                   Adult worms migrate continuously in soft tissues    antigens                                microfilirae
                  and eye
                   Microfiliarae circulate in blood

								
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