Parasitic Protozoans

Parasitic ProtozoansParasitic Protozoans

Lecture 4Lecture 4

2- Flagellates2- Flagellates

1- 1- TrypanosomaTrypanosoma spp. spp.2- 2- LeishmaniaLeishmania spp. spp.3- 3- GiardiaGiardia spp. spp.4- 4- TrichomonasTrichomonas spp. spp.

1- Hemoflagellates1- Hemoflagellates11 - -TrypanosomaTrypanosoma spp. spp.

2- 2- LeishmaniaLeishmania spp spp..Called Hemoflagellates because they have a Called Hemoflagellates because they have a flagellum and require blood medium to flagellum and require blood medium to culture them.culture them.A.K.A. KinetoplastaA.K.A. Kinetoplasta

Flagellum is attached to an undulating Flagellum is attached to an undulating membrane attached to a kinetoplast.membrane attached to a kinetoplast.

There is evidence for sexual reproduction but There is evidence for sexual reproduction but when it occurs is not known.when it occurs is not known.

They can also absorb and use foreign DNA.They can also absorb and use foreign DNA.

Two host life cycleTwo host life cycleHumans and their domestics are Definitive HostHumans and their domestics are Definitive HostInsect vectors are the Intermediate HostInsect vectors are the Intermediate Host

Four life stagesFour life stagesNot all stages occur in all speciesNot all stages occur in all speciesCertain stages are found in specific hostsCertain stages are found in specific hosts• Epimastigotes and promastigotes in insect IHEpimastigotes and promastigotes in insect IH• Amastigoes and trypomastigotes in DHAmastigoes and trypomastigotes in DH

11 - -HemoflagellatesHemoflagellates

11 - -TrypanosomaTrypanosoma spp spp..

11-- Trypanosoma gambiensiTrypanosoma gambiensi22-- T. rhodesiensiT. rhodesiensi

33-- T. curziT. curzi44-- T. lewisiT. lewisi

11-- Trypanosoma gambiensiTrypanosoma gambiensi

22-- T. rhodesiensiT. rhodesiensiDefinitive Host:Definitive Host: Humans. Not Humans. Not pathenogenic to any pathenogenic to any other species. Native other species. Native ruminates serve as ruminates serve as reservoirs for reservoirs for T.b. T.b. rhodesiense, rhodesiense, but not but not T.b. T.b. gambiense.gambiense.Intermediate Host:Intermediate Host: Tsetse fly (Tsetse fly (GlossinaGlossina))Mode of transmission:Mode of transmission: Bite of infected tsetse flyBite of infected tsetse fly

Tsetse fly (Tsetse fly (GlossinaGlossina))

T. b. gambienseT. b. gambiense is found in west is found in west central and central and central Africa.central Africa.

T. b. rhodesienseT. b. rhodesiense found in central found in central and east central and east central AfricaAfrica

Geographic DistributionGeographic Distribution

T. b. gambiense

T. b. rhodesiense

Life cycleLife cycle

Location:Location: Throughout the body in the blood Throughout the body in the blood and tissuesand tissuesPathology:Pathology: Both subspecies cause African Both subspecies cause African Sleeping Sickness.Sleeping Sickness.

T.b. gambiense T.b. gambiense causes chronic, long-term form.causes chronic, long-term form.T.b. rhodesienseT.b. rhodesiense causes an acute form. causes an acute form.

Starts with a small sore at bite.Starts with a small sore at bite.Trypimastigotes divide rapidly and spread Trypimastigotes divide rapidly and spread throughout bodythroughout body

11-- Trypanosoma gambiensiTrypanosoma gambiensi

22-- T. rhodesiensiT. rhodesiensi

Pathology (con’t):Pathology (con’t): Lymph nodes Lymph nodes become swollen and become swollen and congestedcongested

Particularly the Particularly the nodes in necknodes in neckCalled Called Winterbottom’s Winterbottom’s signsign

PathologyPathology

T.b. gambienseT.b. gambiense frequently goes to CNS frequently goes to CNSCauses the chronic, sleepiness associated Causes the chronic, sleepiness associated with African Sleeping Sicknesswith African Sleeping Sickness• Apathy, mental dullness, disturbance of Apathy, mental dullness, disturbance of

coordinationcoordinationIncrease in sleepiness, finally to coma, and Increase in sleepiness, finally to coma, and death.death.Death may also occur from malnutrition, Death may also occur from malnutrition, falling, or other infectionsfalling, or other infections

PathologyPathology

T.b. rhodiensienseT.b. rhodiensiense rarely invade the CNS but rarely invade the CNS but causes death much faster.causes death much faster.

Usually due to invasion of heart tissueUsually due to invasion of heart tissue

Both subspecies produce intermittent periods Both subspecies produce intermittent periods of fever, particularly in early stages.of fever, particularly in early stages.

Due to antigen shifts of the parasite.Due to antigen shifts of the parasite.They can also take antigens from host body and put They can also take antigens from host body and put them on their bodythem on their bodyMuch pathology may be due to heightened immune Much pathology may be due to heightened immune response killing uninfected body cells.response killing uninfected body cells.

PathologyPathology

Trypomastigotes Trypomastigotes in the blood in the blood smear.smear.Can also be in Can also be in cerebrospinal fluid cerebrospinal fluid Serological test Serological test availableavailable

DiagnosisDiagnosis

33 - -Trypanosoma curziTrypanosoma curziDefinitive Host:Definitive Host: Humans, dogs, cats, Humans, dogs, cats, opossums, armadillos, and wood rats.opossums, armadillos, and wood rats.Intermediate Host:Intermediate Host: Reduviid bugs Reduviid bugs (Kissing bug or assassin bugs).(Kissing bug or assassin bugs).Location in the Definitive Host:Location in the Definitive Host: Throughout the body. Throughout the body.

Trypomastigotes in bloodTrypomastigotes in bloodAmastigotes most common in Amastigotes most common in spleen, liver, and muscles, spleen, liver, and muscles, including heartincluding heart

Mode of Transmission:Mode of Transmission: Host rubs Host rubs tryps into bite wound.tryps into bite wound.

Throughout much of central Throughout much of central and South America.and South America.

12-19 million infected12-19 million infected

Annual incidence 561,000Annual incidence 561,000

2-3 million with chronic 2-3 million with chronic symptomssymptoms

45,000 die from disease every 45,000 die from disease every year.year.

A few cases in U.S. in A few cases in U.S. in Maryland, Georgia, Florida, Maryland, Georgia, Florida, Texas, Arizona, New Mexico, Texas, Arizona, New Mexico, California, Alabama, and California, Alabama, and Louisiana.Louisiana.

Geographic DistributionGeographic Distribution

Life cycleLife cycle

22 - -LeishmaniaLeishmania sppspp..

Leishmania donovaniLeishmania donovaniL. tropica.L. tropica.

Definitive Hosts:Definitive Hosts: Humans. Reservoir Humans. Reservoir includes most mammalsincludes most mammalsIntermediate Hosts:Intermediate Hosts: PhlebotomusPhlebotomus sand fly. sand fly.Mode of Transmission:Mode of Transmission: Bite of infected Sand FlyBite of infected Sand FlyLocation in D.H.:Location in D.H.: Immune system, Immune system, including spleen, liver, including spleen, liver, lymph nodes and bone lymph nodes and bone marrowmarrow

Leishmania donovaniLeishmania donovani

Geographic DistributionGeographic DistributionProbably originated in Old WorldProbably originated in Old WorldMoved to New World with slave tradeMoved to New World with slave trade

PathologyPathology

Causes Visceral LeishmaniasisCauses Visceral LeishmaniasisA.K.A. Kala-azar, Dum-Dum FeverA.K.A. Kala-azar, Dum-Dum Fever

Amastigote is engulfed by macrophage.Amastigote is engulfed by macrophage.Macrophage doesn’t kill amastigote.Macrophage doesn’t kill amastigote.Neutrophils and eosinophils will kill amastigotes.Neutrophils and eosinophils will kill amastigotes.

Multiplies, breaks out, and each invades Multiplies, breaks out, and each invades another macrophage.another macrophage.

Also destroys macrophages in the spleen, liver, Also destroys macrophages in the spleen, liver, and lymph nodesand lymph nodesBody starts manufacturing macrophages to Body starts manufacturing macrophages to replace them.replace them.Results in severe wasting and anemiaResults in severe wasting and anemia

PathologyPathologyMacrophage Infected Macrophage Infected with with amastigotesamastigotes of of LeishmaniaLeishmania

Early symptoms include malaise, vomiting, low-Early symptoms include malaise, vomiting, low-grade fevers.grade fevers.Followed with chronic wasting, anemia, enlargement Followed with chronic wasting, anemia, enlargement of abdomen due to greatly enlarged spleen and liver.of abdomen due to greatly enlarged spleen and liver.Death usually follows in 1-2 years if untreated.Death usually follows in 1-2 years if untreated.

PathologyPathology

Some people recover spontaneouslySome people recover spontaneouslyRelated to age and nutritionRelated to age and nutrition

Some people who were treated later develop Post-Some people who were treated later develop Post-Kala-Kala-azarazar dermal leishmanoid dermal leishmanoid

“ “Face bumps”Face bumps”Repeat of treatment usually clears up the bumps.Repeat of treatment usually clears up the bumps.

Life CycleLife Cycle

DiagnosisDiagnosis

AmastigotesAmastigotes in liver tissue, in liver tissue, macrophages, spleen, other organs.macrophages, spleen, other organs.

IFA, ELISA tests have been developed but IFA, ELISA tests have been developed but can’t tell between can’t tell between L. donovaniL. donovani and and L. L. tropica.tropica.Need to eliminate possibility of typhoid, Need to eliminate possibility of typhoid, paratyphoid, malaria, syphilis, paratyphoid, malaria, syphilis, tuberculosis, dyssentery, and relapsing tuberculosis, dyssentery, and relapsing fever which cause similar symptoms.fever which cause similar symptoms.

2- Somato-flagellates2- Somato-flagellates

1- Genital flagellates1- Genital flagellatesTrichomonasTrichomonas spp. spp.

2- Intestinal flagellates2- Intestinal flagellatesGiardiaGiardia spp. spp.

Genital flagellatesGenital flagellatesTrichomonasTrichomonas spp. spp.

Trichomonas vaginalisTrichomonas vaginalis

Definitive Hosts:Definitive Hosts: Humans. Humans. Reservoir includes most Reservoir includes most mammals and birdsmammals and birdsIntermediate Hosts:Intermediate Hosts: NothingNothingMode of Transmission:Mode of Transmission: during sexual inter course during sexual inter course by trophozoiteby trophozoite

Geographic DistributionGeographic DistributionTrichomonasTrichomonas are found in man, monkeys, rodents, are found in man, monkeys, rodents, fowls, pigeons, doves, termites and slugs. fowls, pigeons, doves, termites and slugs. Distributed in all countriesDistributed in all countries

PathologyPathologyCauses milky yellowish irritant vaginal discharge in Causes milky yellowish irritant vaginal discharge in femalefemaleUlceral discharge may occur in maleUlceral discharge may occur in male

Life CycleLife Cycle

In female:In female: Examination of vaqginal Examination of vaqginal discharge for trophozoites and urine discharge for trophozoites and urine samplesampleIn male:In male: Examination of prostatic fluid Examination of prostatic fluid and urine sampleand urine sample

DiagnosisDiagnosis

GiardiaGiardia spp. spp.Intestinal flagellatesIntestinal flagellates

Definitive Hosts:Definitive Hosts: Humans. Humans. Intermediate Hosts:Intermediate Hosts: Nothing NothingMode of Transmission:Mode of Transmission: quadri-nucleated cyst in quadri-nucleated cyst in contaminated food and contaminated food and drinkdrinkFlies and cockroaches play Flies and cockroaches play an important role in an important role in transmissiontransmission

Geographic DistributionGeographic Distribution

Worldwide, more prevalent in warm climatesWorldwide, more prevalent in warm climates

Children are Children are affectedaffectedMucus production, Mucus production, diarrha, diarrha, dehydration, dehydration, intestinal pain, intestinal pain, weight loss.weight loss.

PathologyPathology

Life CycleLife Cycle

Microscopic examinationMicroscopic examination of fecal of fecal material for identification of material for identification of trophozoite.trophozoite.PCR analysisPCR analysis for detection of giardia for detection of giardia DNA from both trophozoites and cystsDNA from both trophozoites and cysts

DiagnosisDiagnosis