KU BIOL 480 Exam 1

definition of parasitism

An organism that associates with a host at least once throughout their life with interspecific association

Pathogen

When harm is expressed (not all parasites)

Pathogenicity

The property of causing a disease

Ectoparasite

Lives outside the host

Endoparasite

Live inside the host

Mesoparasite

Lives with a portion of their body inside/outside

Zoonosis

Can transfer from animals to human

reservoir host

infected organism (usually an animal) which makes the parasite available for transmission to other hosts

Definitive Host

Parasite undergoes sexual reproduction

Intermediate Host

Parasite develops but NO sexual reproduction

Paratenic

Parasite has no development

Prevalence

# of individuals in a pop infected (50 pigs, 10 infected, Prevalence = 20%)

Intensity

# of individuals of a PARASITE per infected host (10 pig, 250 worm, mean intensity = 25 worm) (1 pig, 25 worm, intensity = 25 worm)

Trophozoite

Membrane-bound, motile, active feeding stage, pathogenic stage

Cyst

Outer protective wall, able to survive outside of host, resting stage, critical for diagnosis

Giardia duodenalis

• host(s), zoonotic? site in host,

  • Zoonotic, multiple species serve as host, asexual reproduction, gastrointestinal tract (Small Intestine)

• disease caused, sources of pathogenicity

  • Giardiasis, Direct contact/ Toxic substance produced by parasite (antigenic)/ Loss of absorptive surface

• diagnosis (life stage and type of sample), symptoms, treatment, transmission.

  • Cysts in stool, Fat in stool/ Explosive Diarrhea/ Dehydration/weight loss/ intestinal discomfort, Antibiotics

  • Transmission = 6 Fs (Fingers, food, feces, flies, fluids, fomites (object capable of carrying infection))

Giardia duodenalis Life Cycle

Phylum Parabasalia: Order Trichomonadida: general features

undulating membrane, recurrent flagellum, axostyle

Trichomonas vaginalis

• host(s), site in host,

  • Monoxenous, Upper vagina and urethra (female)/ urethra and prostate (males)

• disease caused, sources of pathogenicity,

  • Trichomoniasis, genitals, spreads though sexual intercourse

• diagnosis (life stage and type of sample), symptoms, treatment (if any), transmission;

  • Vaginal smear for trophozoites (Nucleic acid amplification test); intense itching, possible tissue damage, asymptomatic in males; antibiotics

Trichomonas vaginalis Life Cycle

Trichomonas gallinae

• host(s), monoxenous or heteroxenous?,

  • Birds, monoxenous -

• site in host, transmission, disease caused;

  • Mouth & throat; feeding/contamination; Avian trichomoniasis

Tritrichomonas foetus

• host(s), monoxenous or heteroxenous?,

  • Cattle; monoxenous

• site in host, pathology, transmission, disease caused

  • Vagina & uterus in cows, preputial cavity in bulls; abortion in cattle, infertility in cows, bulls asymptomatic; Venereal disease cattle (intercourse)

• problem with cryopreservation

  • Trophozoite can survive cryopreservation

Histomonas meleagridis

• cyst?, monoxenous or heteroxenous?, host(s),

  • No cyst; Heteroxenous (intestinal nematode of birds as intermediate host); Gallinaceous birds

• site in definitive host, disease caused.

  • Lesions in caecum, liver; Histomonas (Blackhead disease)

Entamoeba histolytica

• host(s), site occupied within host (1º & 2º [i.e., ectopic] infections)

  • Monoxenous (Humans); 1º: large intestine, 2º: ectopic sites if the conditions are met

• disease caused, pathogenicity, symptoms, diagnosis of infection, treatment, transmission.

  • Amoebiasis (Amoebic Dysentery); Cyst both infective and diagnostic stage; dysentery, 4-6 loose stools per day, cramps, vomiting, blood in stool; Diagnosis: Large intestine = cysts or trophs in feces, ectopic = x-ray; Antibiotics; fecal contamination of water/food

Entamoeba histolytica Life Cycle

Non-pathogenic species that parasitize humans

Entamoeba coli, E. dispar, E. hartmanni, E. moshkoviski, Endolimax nana, lodamoeba buetschlii all in large intestine

Acanthamoeba polyphaga

• disease caused, pathogenicity, transmission (multiple possible sources of infection), normal habitat.

  • Acanthamoeba keratitis (AK); ulceration of cornea; hot tubs and contaminated contact lens fluid; topical antibiotics; commonly found in lakes, swimming pools, tap water, and heating and air conditioning units

Acanthamoeba polyphaga Life Cycle

ALVEOLATA: Phylum Ciliophora

• general features (macro and micronuclei, etc.), mode of locomotion

  • Multiple Cilia, Infraciliature, Macro/Micronucleus

Balantidoides coli

• host(s), site, disease caused, pathogenicity, diagnosis of infection, treatment, transmission;

  • Zoonotic (pigs as reservoir), monoxenous; only ciliated and the largest protozoon known to infect humans; Balantidiosis (asymptomatic in pigs); produces enzyme lyse host cell, ulcer of colon (could perforate -> ectopic); cecum & colon in cyst form (feces); antibiotic; water as vehicle or human-human transmission+

Ichthyopthirius multifilis

• host(s), site, disease caused, pathogenicity, diagnosis of infection.

  • Freshwater fish, monoxenous; small white spots on fish; look for trophonts

Ichthyopthirius multifilis life cycle

Phylum Apicomplexa

• basic features, key organelles of apical complex;

  • Apical complex (penetration of host cells (conoid), made of secretory organelles and specific cytoskeletal elements), all intracellular parasitic, single nucleus, no pseudopods, cilia, or flagella ext. microgametes)

Phylum Apicomplexa three distinct reproductive processes

Phylum Apicomplexa initial life-cycle stages

Subphylum Aconoidasida: distinguishing feature

Conoid (tip) only in ookinete stage

Order Haemospororida

• general features (sporozoites naked, etc.)

  • Life in blood cells at sometime in life, zygote motile, sporozoites naked, heteroxenous

• diversity (three main genera with ~475 species)

  • Plasmodium, Hemoproteins, Leucocytozoonosis

Plasmodium

• types of vertebrate hosts, types of invertebrate hosts;

  • Lizards, birds, monkeys

• 1 zoonotic species and its reservoir hosts

  • Plasmodium knolesil; Reservoir host: macaques (monkey)

Plasmodium Life Cycle

Plasmodium falciparum

• (50%) MOST DEADLY

• Malignant Tertian Malaria, infects all ages, relapse 1-3 years

• Gametocytes banana-shaped, 65% of RBC, blood becomes “sticky”

• Symptoms: Cytoadherence (sticky), rosetting (binding of RBCS), RBC Cancer

Plasmodium vivax

• (43%)

• Benign Tertian Malaria, infects young RBC, only 1 merozoite/RBC, relapse 8 years

• Gametocyte circular-shaped, lots of Schüffner’s dots

• Symptoms: Rosetting (binding of infect/uninfected RBC, causes clots)

Plasmodium malariae

• (7%)

• Quartan Malaria, Paroxysms 72 hr, infects aging RBC, 1 parasite/20,000 cells, relapse 53 year

• Band-shaped trophozoite

Plasmodium ovale

• (1%)

• Mild Tertian Malaria, Paroxysms 48 hr, infects young RBC, relapse months

• Fewer merozoites per schizont

• Gametocyte circular-shaped w/ red, more little dots

Plasmodium Symptoms

Jaundice, Anemia, Enlarged spleen

Paroxysm

Periodic fever/chills caused by release of erthocytic merozoites into bloodstream

• P. vivax: every 48 hrs.

• P. ovale: every 48 hrs.

• P. malariae: every 72 hrs.

• P. falciparum: every 48 hrs, not as synchronous

Relapse

When paroxysms reappears after a number of paroxysm-free months (P. ovale) or years (P. vivax)

From 2nd population of dormant sporozoites in the liver becoming active

Recrudescence

When paroxysms reappears after a number of paroxysm free years (P. falciparum and P. malariae)

From merozoites remaining low until rapid schizogony

Strategies of malaria control

elimination of mosquito hosts (= vector control; destroy mosquito breeding sites, etc.), treat infected people (antimalarials, ACT, mass drug administration), prevent uninfected people from becoming infected (mosquito nets, vaccines, spraying), individual resistance to malaria

Babesia bigemina

• intermediate and definitive hosts

  • Def: boophilus (tick), Inter: cattle, deer, zebu, water buffalo

• disease caused, pathology

  • Babesiosis (Texas red-water fever); destroys RBCs, blood in urine

Babesia microti

• intermediate, definitive, and reservoir hosts

  • Def: Ixodes scapularis (deer tick), Inter: humans, Reservoir: meadow moles ZOONOTIC!!

• geography, pathogenicity

  • Babesiosis (Nantucket fever), fever, chills, fatigue, headache

Subphylum Conoidasida: distinguishing features

Conoid in all life cycle stages, zygote not motile, sporozoites in cysts, monoxenous, sporogony (asexual) occurs outside of host

Order Coccidia: general features

Parasites of vertebrates (incl. humans), Mature gametocytes intracellular, Undergoes schizogony

Eimeria morphology and lifecycle

4 sporocysts, 8 sporozoites, monoxenous

Cystoisospora morphology and lifecycle

2 sporocysts, 8 sporozoites, monoxenous

Cyclospora morphology and lifecycle

2 sporocysts, 4 sporozoites, monoxenous

Toxoplasma morphology and lifecycle

2 sporocysts, 8 sporozoites, heteroxenous

Sarcocystis morphology and lifecycle

2 sporocysts, 8 sporozoites, heteroxenous

Cryptosporidium morphology and lifecycle

0 sporocysts, 4 sporozoites, monoxenous

Eimeria

• incredible diversity of species (1,500+ species),

  • Host and Tissue specific, each species has a specific host

• infections self-limiting (what does this mean, contrast to Haemospororida?), general name for diseases caused

  • Self-limiting, infection will run its course and resolve on its own without external intervention

  • Only 3 cycles of schizogony, while Haemospororida will infinitely reproduce

Eimeria tenella

• pathogenicity, why is parasitemia of cells of mucosa of caecum so high?

  • Specific to epithelial cells of domestic chickens

  • Parasitemia of cells high due to constant generation cycling.

Eimeria tenella Life Cycle

Cystoisopspora belli

• host(s), individuals most at risk, disease caused, pathologenicity

  • Humans; immunocompromised individuals; Cystoisoproiasis; epithelial cells of jejunum of intestine, can cause death

Cyclospora cayatensis

• symptoms, pathology, individuals most at risk;

  • Cyclosporiasis; fatigue, diarrhea, weight loss; immunocompromised, self-liming for only immunocompetent

Toxoplasma gondii

• infective stages to each host

  • Sporozoite (C): in oocysts (environment), infective to intermediate hosts

  • Tachyzoite (A): highly active form (cats and human), in cells of any organs or blood, disease stage

  • Bradyzoite (B): still in cats and humans, in zoitocyst (tissue cyst)

• Serious in pregnant women (fetus), immunocompromised; transmits through food-bone, zoonotic, and congenital

Toxoplasma gondii Life cycle

Sarcocystis Life Cycle

distinctive rice grained zoitocyts

Cryptosporidium parvum

• hosts: Zoonotic, +150 spp. Of vertebreates as reservoir hosts, monoxenous

• disease caused, pathogenicity, diagnosis, common transmission scenario

  • Cryptosporidiosis; infects intestinal cells; oocysts in feces (lacks sporocytes); fecal contamination surfaces or water;

• potential issue with phylogenetic affinities (Order Cryptosporidia)

  • Each treatment is extremely different

Order Gregarinasina

association with mandibulate arthropods only

Naegleria fowleri

Facultative Parasite

• disease caused, pathogenicity, diagnosis (life stage and type of sample), treatment(?), transmission

  • PAM (Primary Amoebic Meningoencephalitis); Trophozoites into nasal passages, enters brain via cribriform plate, lyse brain tissue with amoebocytes; diagnosis and treatment difficult (PCR)

Naegleria fowleri Life Cycle

Monoxenous, Facultative, migrates to brain via olfactory nerves

Class Kinetoplastea

• general features

  • Reproduces asexually via binary fission, vertebrate considered definitive host, invertebrate intermediate

  • Kinetoplast: a specialized region of the mitochondria of trypanosomatids that harbors the most complex and unusual mitochondrial DNA found in nature

4 major trophozoite forms

• Amastigote:

  • Round body, extremely short flagellum, antieror kinetoplast, intracellular vertebrate

• Promastigote:

  • Elongated body, normal kinetosome, free flagellum, extracellular invertebrates

• Epimastigote

  • Elongated body, kinetoplast near nucleus, short undulating membrane, extracellular invertebrates

• Trypomastigote: Posterior kinetoplast, Extracellular vertebrate

  • Pericyclic: long slender form

    • Free flagellum

  • Metacyclic: Short stubby form (infective)

    • No flagellum

Anterior station species

Trypanosoma brucei

Posterior station species

Trypanosoma cruzi, Leishmania

Trypanosoma brucei

• Rhodesiense (8%)

  • Definite host: Humans

  • Reservoir hosts: Zoonotic (rhinos, hyenas)

  • Intermediate: Glossina morsitans (savannah)

  • Disease: Acute African sleeping sickness (East)

    • Fatal in 6 months,

• Gambiense (92%)

  • Definitive host: Humans

  • Reservoir hosts: Zoonotic (pigs, bulls)

  • Intermediate: Glossina palpalis (forest)

  • Disease: Chronic African sleeping sickness (West)

• Brucei

  • Definite host: Bulls, Horse, Donkey

  • Reservoir hosts: None

  • Intermediate: Glossina paldipes

  • Disease: Nagana (sleeping sickness in cattle)

Trypanosoma cruzi

• morphology, life cycle, hosts (intermediate, definitive and reservoir)

  • Definitive host: Humans

  • Reservoir hosts: Zoonotic o Intermediate: Triatoma Rhodnius (kissing bug)

  • Disease: South American sleeping sickness

• site occupied within hosts

  • Cardiac and skeletal muscle

• disease caused, pathogenicity (acute and chronic phases of Chaga’s disease), diagnosis,

  • Changas Disease

    • Acute; affects children, romana sign (swollen eye at bite)

    • Chronic; adults, 70% are asymptomatic, could affect the heart or digestive organs

• explanation for why treatment is difficult, transmission, control, geographic distribution, recognize diversity of species in other hosts

  • Transmits through vector and blood transfusions; does not respond well to drugs

Trypanosoma cruzi Life Cycle

Leishmania

• general features (only promastigotes and amastigotes, etc.);

  • No trypomastigote form, All species with amastigote form in vertebrate, all species with promastigote form in invertebrate, Generally heteroxenous (human/sandfly)

Leishmania Life Cycle

Cutaneous leishmaniasis tropica

• Host: Human (Def), Phelebotomus (Inter, Old World), Rodents (vector, zoonotic)

• Site: At bite, in reticuloendothelial system (lymph)

• Disease/ Pathogenicity: Cutaneous Leishmaniasis (Oriental Sore); ulcerating dry lesions, painless, frequently multiple, self healing

• Diagnosis: Amastigotes in skin lesions

• Geographic Dist.: Middle East, India

• Treatment: Protective immunity

Cutaneous leishmaniasis major

• Host: Human (Def), Phelebotomus (Inter, Old World), Rodents (vector, zoonotic)

• Site: At bite, in reticuloendothelial system (lymph)

• Disease/ Pathogenicity: Cutaneous Leishmaniasis (Oriental Sore); Rapid necrosis, multiple wet sores, inflammation, slow to heal, severe scarring

• Diagnosis: Amastigotes in skin lesions

• Geographic Dist.: N/W Africa, Middle East, Central Asia

• Treatment: Protective immunity

Cutaneous leishmaniasis mexicana

• Host: Human (Def), Lutzomyia (Inter, New World), Rodents and Oppossum (vector, zoonotic)

• Site: cutaneous; nasopharyngeal and visceral (rare)

• Disease/ Pathogenicity: Chicloro ulcer (Bay sore); Ulcerating lesions, single or multiple, often self-healing

• Diagnosis: Amastigotes in skin lesions

• Geographic Dist.: Central and South America

• Treatment: Protective immunity

Mucocutaneous leishmaniasis

• Host: Human (Def), Lutzomyia (Vector, New World)

• Site: At bite to mucocutaneous tissue

• Disease/ Pathogenicity: Espundia, ulcerating lesions that’s disfiguring, degenerates’ cartilage

• Diagnosis: amastigotes from mucosal lesions and lymph node

• Geographic Dist.: Central and South America

• Treatment: Pentavalent antimonial

Visceral leishmaniasis

• Host: Human (Def), Phlebotomus (Vector, Old World)

• Site: In cells of reticuloendothelial system (spleen, bone marrow, lymph nodes)

• Disease/ Pathogenicity: Visceral Leishmaniasis, Persistent fever, splenomegaly, weight loss, rash, fatal within two years

• Diagnosis: amastigotes in smear, PCR detection

• Geographic Dist.: Ethiopia, Sudan, Kenya, India, China, Bangladesh, Burma

• Treatment: Miltefosine