Apicomplexa structure. Phylum: Apicomplexa Class : Sporozoea Subcl. : Coccidia Order : Eucoccidiida Subor. : Eimeriina (Tissue & Intestinal Coccidia)

Apicomplexa Apicomplexa structurestructure

Phylum: ApicomplexaPhylum: Apicomplexa

Class : SporozoeaClass : SporozoeaSubcl. : CoccidiaSubcl. : CoccidiaOrder : EucoccidiidaOrder : EucoccidiidaSubor. : Subor. : Eimeriina (Eimeriina (Tissue & Intestinal CoccidiaTissue & Intestinal Coccidia))

FamilyFamily : : Eimeriidae CryptosporiidaeEimeriidae Cryptosporiidae SarcocystidaeSarcocystidae

Genus : Genus : Isospora Cyclospora Cryptosporidium Sarcocystis ToxoplasmaIsospora Cyclospora Cryptosporidium Sarcocystis Toxoplasma

Species: Species: belli cayetanensis parvum hominis suihominis gondiibelli cayetanensis parvum hominis suihominis gondii hominishominis natalensis natalensis

Intestinal Coccidia Intestinal Coccidia

1-Isospora belli1-Isospora belli

Causal Agent:Causal Agent:Infects the epithelial cells of the small intestine, and is the least Infects the epithelial cells of the small intestine, and is the least common of the three intestinal coccidia that infect humans.common of the three intestinal coccidia that infect humans.

Geographic Distribution:

Worldwide, especially in tropical and subtropical areas. 

Infection occurs in immunodepressed individuals, and outbreaks have been reported in institutionalized groups.

MorphologyMorphology

Oocyst form:Oocyst form:

Average size 30Average size 30μμm in length by 12 m in length by 12 μμm in widthm in width

Immature oocystMature oocyst

Stained oocyst

Life Cycle Life Cycle of of Isospora Isospora belli belli

SymptomsSymptoms

--Infections often are asymptomaticand self-limitedInfections often are asymptomaticand self-limited ..

-Symptomatic Infection include;-Symptomatic Infection include; - acute, non bloody diarrhea - acute, non bloody diarrhea - malabsorption syndrome - malabsorption syndrome - Severe diarrhea - Severe diarrhea - Eosinophilia may be present (differently from other - Eosinophilia may be present (differently from other

protozoan infections ).protozoan infections ).

. .

PathogenesisPathogenesis

- Villous atrophy commonly associated with - Villous atrophy commonly associated with malabsorption Syndrome.malabsorption Syndrome.

-It will be remembered that this condition is -It will be remembered that this condition is also seen at times in giardiasisalso seen at times in giardiasis

Pathology of IsosporiasisPathology of Isosporiasis

Laboratory DiagnosisLaboratory DiagnosisStool examinations and microscopic Stool examinations and microscopic

Repeated stool examinations and concentration procedures are Repeated stool examinations and concentration procedures are recommended.recommended.

Examination of duodenal specimens by biopsy or string test Examination of duodenal specimens by biopsy or string test (Enterotest®) may be needed.(Enterotest®) may be needed.

  - They can also be stained by modified acid-fast procedure or - They can also be stained by modified acid-fast procedure or auramine-rhodamine stains.auramine-rhodamine stains.

-The modified acid-fast procedure is especially useful.-The modified acid-fast procedure is especially useful.

1. Wet mount

Under UV fluorescence microscopy, the oocyst wall has blue autofluoresces as illustrated in Figures C and F.

2. Modified acid-fast stain

A blue-green background, or contrasting counterstain.

Oocyst will stain light pink to deep purple, while others may be unstained.

This staining method is the easiest and most practical, and provides a permanent record.

TreatmentTreatment

Trimethoprim-sulfamethoxazole combination( trimethoprim Trimethoprim-sulfamethoxazole combination( trimethoprim 160 mg, sulfamethoxazole 800 mg ) is the drug of choice,”in 160 mg, sulfamethoxazole 800 mg ) is the drug of choice,”in immunosuppressed person every 6 hours for 10 days, followed immunosuppressed person every 6 hours for 10 days, followed by the same dose twice daily for 3 weeksby the same dose twice daily for 3 weeks..

Combined pyrimethamine and sulfadiazine has also been Combined pyrimethamine and sulfadiazine has also been shown to be anshown to be an effective treatment.effective treatment.

Albendazole, 400mg twice daily for 20 days, and ornidazole, 2 Albendazole, 400mg twice daily for 20 days, and ornidazole, 2 g in a single dose on days 1, 15, and 20 have been effective.g in a single dose on days 1, 15, and 20 have been effective.

2- Cryptosporidium spp.2- Cryptosporidium spp.

Many species of Many species of CryptosporidiumCryptosporidium exist that infect exist that infect humans and a wide range of animals (including humans and a wide range of animals (including mammals, birds, reptiles and fish).mammals, birds, reptiles and fish).

Cryptosporidium spp.:Cryptosporidium spp.:Human spp.:Human spp.:

C. parvumC. parvum and and Cryptosporidium hominisCryptosporidium hominis (formerly (formerly known as known as C. parvumC. parvum anthroponotic genotype or anthroponotic genotype or genotype 1).genotype 1).

Infections by Infections by C. felisC. felis, , C. meleagridisC. meleagridis, , C. canisC. canis, and , and C. C. murismuris have also been reported. have also been reported.

Cryptosporidium parvumCryptosporidium parvumIt is a opportunist parasite of human It is a opportunist parasite of human both;Immunocompromised and immunocompetent both;Immunocompromised and immunocompetent individuals.individuals.

One of the major characteristic is the lack of host One of the major characteristic is the lack of host specifity that sets Cryp. apart from the other coccidia.specifity that sets Cryp. apart from the other coccidia.

C. parvum isolates:C. parvum isolates: - one containing human isolates- one containing human isolates - other containing mostly domesticated isolates- other containing mostly domesticated isolates

Morphology, BiologyMorphology, Biology

Oocysts of parasiteOocysts of parasite

Life cycleLife cycle

Life cycle in hostLife cycle in host

Geographic Distribution:Geographic Distribution:

Since the first reports of human cases in 1976, Since the first reports of human cases in 1976, CryptosporidiumCryptosporidium has been found worldwide.  has been found worldwide. 

Outbreaks of cryptosporidiosis have been reported in Outbreaks of cryptosporidiosis have been reported in several countries.several countries.

The most remarkable being a waterborne outbreak in The most remarkable being a waterborne outbreak in 1993, that affected more than 400,000 people.1993, that affected more than 400,000 people.

Clinical FeaturesClinical Features

    results in a wide range of manifestations, from asymptomatic results in a wide range of manifestations, from asymptomatic infections to severe, life-threatening illness.infections to severe, life-threatening illness.

Incubation period is from 2 to 10 days.Incubation period is from 2 to 10 days.    Watery diarrhea, accompanied by dehydration, and Watery diarrhea, accompanied by dehydration, and malabsorption syndrome.malabsorption syndrome.

    In immunocompetent persons, symptoms are usually short In immunocompetent persons, symptoms are usually short lived (1 to 2 weeks).lived (1 to 2 weeks).In immunocompromised it can be chronic and more severe In immunocompromised it can be chronic and more severe patients, especially those with CD4 counts <200/µl. patients, especially those with CD4 counts <200/µl. 

infections in other organs including:infections in other organs including: other digestive tract organs, the lungs, and possibly conjunctiva.other digestive tract organs, the lungs, and possibly conjunctiva.

EpidemiologyEpidemiology

Crypto. as zoonosis may be acquired from domestic animals( calves Crypto. as zoonosis may be acquired from domestic animals( calves and ships).and ships).

Children are more commonly infected than adults.Children are more commonly infected than adults.

Non-breast-fed infants have more infection than breast-fed infants.Non-breast-fed infants have more infection than breast-fed infants.

For reduce the risk of waterborne Cryp. boil drinking water for 1 For reduce the risk of waterborne Cryp. boil drinking water for 1 minute or filter drinking water with 1µm pore diameter.minute or filter drinking water with 1µm pore diameter.

Laboratory DiagnosisLaboratory Diagnosis

Acid-fast staining methodsAcid-fast staining methods

The duodenal string test ( Enterotest ) has also been used to recover The duodenal string test ( Enterotest ) has also been used to recover oocysts. oocysts. 

Identify organisms in intestinal biopsy material. Identify organisms in intestinal biopsy material. 

Immunofluorescence microscopyImmunofluorescence microscopy

For greatest sensitivity and specificity, it is the method of For greatest sensitivity and specificity, it is the method of choice (followed closely by enzyme immunoassays).choice (followed closely by enzyme immunoassays).

Molecular methods are mainly a research tool (PCR).Molecular methods are mainly a research tool (PCR).

1. Wet mount

In bright-field microscopy oocysts appear as small round structures (4 to 6 µm) similar to yeasts.

They do not autofluoresce. This method is useful for Cyclospora, especially when low numbers of oocysts can be obscured by other fecal elements

2. Modified acid-fast stain

Oocysts (4 to 6 µm) often have distinct oocyst walls and stain from light pink to bright red.

TreatmentTreatment

Infection in healthy, immunocompetent persons is self-limited. Infection in healthy, immunocompetent persons is self-limited.

  Nitazoxanide has been approved for treatment of diarrhea caused in Nitazoxanide has been approved for treatment of diarrhea caused in immunocompetent patients. immunocompetent patients.

    *The effectiveness of nitazoxanide in immunosuppressed persons is *The effectiveness of nitazoxanide in immunosuppressed persons is unclear.unclear.

*For persons with AIDS, anti-retroviral therapy, which improves *For persons with AIDS, anti-retroviral therapy, which improves immune status, will also reduce oocyst excretion and decrease immune status, will also reduce oocyst excretion and decrease diarrhea associated with cryptosporidiosis.diarrhea associated with cryptosporidiosis.

* In AIDS patients oral paromomycin appears to be an active and well-* In AIDS patients oral paromomycin appears to be an active and well-tolerated suppressive treatment. tolerated suppressive treatment.

سوالسوال

سایر -1 -1 از را کریپتوسپوریدیوم ویزگیهایی سایر چه از را کریپتوسپوریدیوم ویزگیهایی چهکند؟ می متمایز کند؟ کوکسیدیاها می متمایز کوکسیدیاها

است؟ -2 -2 کوکسیدیا یک سیکلوسپورا است؟ چرا کوکسیدیا یک سیکلوسپورا چرا

Cyclospora cayetanensisCyclospora cayetanensis

 * This species was recognized in 1994 from Peruvian isolates of human.It appears that all human cases are caused by this species.

The organism, variously referred to as; a large Cryptosporidium , a coccidian-like body , a cyanobacterium-like body, and a blue-green alga.

It is a coccidian parasite that infects a range of vertebrates including reptiles, insectivores , and rodents.

Geographic DistributionGeographic Distribution

Cyclosporiasis is most common in tropical and Cyclosporiasis is most common in tropical and subtropical areas. subtropical areas. 

Since 1990, at least 11 foodborne outbreaks of Since 1990, at least 11 foodborne outbreaks of cyclosporiasis, affecting approximately 3600 cyclosporiasis, affecting approximately 3600 persons, have been documented in the United persons, have been documented in the United States and Canada.States and Canada.

Cyclospora oocystsCyclospora oocysts

Coccidian life cyclesCoccidian life cycles

are quite varied:are quite varied:

1-completing their development in a single host 1-completing their development in a single host such as Cryptosporidium. such as Cryptosporidium.

2-require a period of maturation outside the host 2-require a period of maturation outside the host such as Isospora.such as Isospora.

3-others require a second host3-others require a second host

Life cycle of Cyclospora Life cycle of Cyclospora

Clinical FeaturesClinical Features

Cyclosporiasis is clinically indistinguishable from Cryp. And Cyclosporiasis is clinically indistinguishable from Cryp. And IsosporiasisIsosporiasis

*symptomatic include watery diarrhea,.  anorexia, weight loss, *symptomatic include watery diarrhea,.  anorexia, weight loss, abdominal pain, nausea and vomiting, myalgias, low-grade abdominal pain, nausea and vomiting, myalgias, low-grade fever, and fatigue.fever, and fatigue.

  * Untreated infections typically last for 10-12 weeks and may * Untreated infections typically last for 10-12 weeks and may follow a relapsing course ( AIDS patients).follow a relapsing course ( AIDS patients).

Infections, especially in disease-endemic settings can be Infections, especially in disease-endemic settings can be asymptomatic.asymptomatic.

PathologyPathology

Inflammatory changes , villous atrophy, Inflammatory changes , villous atrophy, and crypt hyperplasia of jejunal tissue and crypt hyperplasia of jejunal tissue have been reported from patient with have been reported from patient with diarrhea and Cyclospora oocysts in stool diarrhea and Cyclospora oocysts in stool specimensspecimens

Laboratory DiagnosisLaboratory Diagnosis

Microscopic examinationMicroscopic examination The sediment can be examined microscopically with The sediment can be examined microscopically with

different techniques:different techniques:wet mountswet mounts (by conventional light microscopy, which (by conventional light microscopy, which can be enhanced by can be enhanced by UV fluorescence microscopyUV fluorescence microscopy or or differential interference contrast. differential interference contrast.

stained smearsstained smears (using (using modified acid-fast stainmodified acid-fast stain or a or a modified modified safraninsafranin stain stain) )

1. Wet mount

Under UV fluorescence microscopy, the oocyst wall autofluoresces.

The oocysts are variably stained.

some may appear collapsed or distorted on one side.

They may contain granules

2. Modified acid-fast stain

3. Safranin stainOocysts stain uniformly, red to reddish-orange. This uniform staining decreases the risk of misdiagnosis.

Sarcocystis spp.Sarcocystis spp.History:History:

These parasites were first described in mice by Miescher in 1843.These parasites were first described in mice by Miescher in 1843.

Host:Host: - - Defintive hosts –Defintive hosts – - Intermediate hosts- Intermediate hosts

Human sarcosporidiaHuman sarcosporidia : : 1- human as accidental intermediate host

- S. lindemanii

2- human as accidental definitive host : - S. hominis( S. bovihominis) - S. suihominis

S. lindemanni

Morphology of SarcocystisMorphology of Sarcocystis

1- 1- Tissue cystTissue cyst ( Miescher’s tubules)( Miescher’s tubules)

Differentiale diagnosis Sarc. from Toxo. cyst in many cases;

-Size

-The limiting membrane

- Septa divided the cyst into compartments.

2- 2- CystizoiteCystizoite( bradyzoite): ( 4 to ( bradyzoite): ( 4 to 9µm 8× 12 to 16µm ) 9µm 8× 12 to 16µm )

3- Oocyst3- Oocyst

Sarcocystis cystSarcocystis cyst

Life cycle of SarcocystisLife cycle of Sarcocystis

Pathogenesis and SymptomsPathogenesis and Symptoms

--Muscular sarcocystosis:-Most human cases are asymptomatic.-Most human cases are asymptomatic.

-Symptomatic form:-Symptomatic form: - Myositis, dyspnea, and wheezing associated with eosinophilia.Myositis, dyspnea, and wheezing associated with eosinophilia.

- Intestinal sarcocystosisIntestinal sarcocystosis: : - Symptoms including; nasusea , stomach pains, diarrhea within 3 to 6 hours Symptoms including; nasusea , stomach pains, diarrhea within 3 to 6 hours

after ingested meat.after ingested meat.- Instance of ingest pork infected symptoms persisted for 2 to 3 weeks. Instance of ingest pork infected symptoms persisted for 2 to 3 weeks.

Pathology of Pathology of SarcocystisSarcocystis

Merozoite of sarcocystis in blood smesr

Laboratory diagnosisLaboratory diagnosis

1- Intestinal infections:

* Exam stools for detecting of sporulated sporocysts, using zinc sulfate flotation.

2- Muscle biopsy :Microscopic examination of a muscle biopsy CT scan or MRI can sometimes visualize sarcocysts in the muscles. Complete Blood Count (CBC) , to reveal eosinophilia, may also be helpful.

3- Serologic tests include :IFA testImmunoblotting test (may be useful for muscle infections)

Serologic tests may not be widely available.

Oocyst formsOocyst forms

Toxoplasma gondiiToxoplasma gondiiCausal Agent:Causal Agent:It is an obligate intracellular protozoan parasite .It is an obligate intracellular protozoan parasite .

It’s defintive host is the house cat and certain other Felidae.It’s defintive host is the house cat and certain other Felidae.

History:History: It was originally described in a North African rodent called ” Ctenodactylus It was originally described in a North African rodent called ” Ctenodactylus

gondi”.gondi”.

Geographic DistributionGeographic Distribution

- Toxoplasmosis is one of the most common of humans infections - Toxoplasmosis is one of the most common of humans infections throughout the world. throughout the world. 

- Infection is more common in warm climates than in cold climates and - Infection is more common in warm climates than in cold climates and

mountainous regions.mountainous regions.

    - High prevalence of infection in France and Central America (has been - High prevalence of infection in France and Central America (has been related to the frequency of stray cats in a climate favoring survival of related to the frequency of stray cats in a climate favoring survival of oocysts. oocysts. 

- The overall seroprevalence in the United States between 1988 and 1994 - The overall seroprevalence in the United States between 1988 and 1994 was found to be 22.5%, was found to be 22.5%,

with seroprevalence among women of childbearing age (15 to 44 years) with seroprevalence among women of childbearing age (15 to 44 years) of 15% .of 15% .

Different form of ToxoplasmaDifferent form of Toxoplasma

**In definitive host:In definitive host:1- Immature oocyst:1- Immature oocyst:

( 9- 10 µm in width by 11- 14 µm ( 9- 10 µm in width by 11- 14 µm in length)in length)

**In intermediate host:In intermediate host:2- Tachyzoite ( toxoplasma trophozoite )2- Tachyzoite ( toxoplasma trophozoite )

3- Tissue cyst: 3- Tissue cyst:

(contain slower-developing bradyzoite)(contain slower-developing bradyzoite)

Life cycle of Life cycle of ToxoplasmaToxoplasma

Life cycleLife cycle

In vitro culture (MCR-5): In vitro culture (MCR-5): Toxoplasma gondiiToxoplasma gondii

Stained tachyzoites, microscopic preparationStained tachyzoites, microscopic preparation

PathogenesisPathogenesis

1- Attchment to nuclated cells of the 1- Attchment to nuclated cells of the intermediate host by secretory lectin.intermediate host by secretory lectin.

2- Secretion of peneterating-enhancing-2- Secretion of peneterating-enhancing-factor(P.E.F).factor(P.E.F).

3- Endodyogeny proliferation of parasite in 3- Endodyogeny proliferation of parasite in nuclated cells and disruption of them.nuclated cells and disruption of them.

Clinical FeaturesClinical Features

1-Acpuired Toxoplasmosis:1-Acpuired Toxoplasmosis: - - Asymptomatic infection:Asymptomatic infection:

    - Symptomatic infection:- Symptomatic infection: *lymphadenopathy( mild form):*lymphadenopathy( mild form):

* Sever form Symptoms:* Sever form Symptoms: Pneumonitis, hepatitis, encephalomyelitis, myocarditis, retinochoroiditis, Pneumonitis, hepatitis, encephalomyelitis, myocarditis, retinochoroiditis,

maculopapular rashs,…maculopapular rashs,…

In immunodeficient patients :In immunodeficient patients : central nervous system (CNS) disease , retinochoroiditis, or pneumonitiscentral nervous system (CNS) disease , retinochoroiditis, or pneumonitis ..  

Toxoplasmosis in patients being treated with immunosuppressive drugs may be due to Toxoplasmosis in patients being treated with immunosuppressive drugs may be due to either newly acquired or reactivated latent infectioneither newly acquired or reactivated latent infection

2- Congenital toxoplasmosis2- Congenital toxoplasmosis

    The incidence and severity of congenital The incidence and severity of congenital toxoplasmosis vary with the trimestertoxoplasmosis vary with the trimester

- in the first trimaster:- in the first trimaster:abortion, microcephaly, hydrocephalus,….abortion, microcephaly, hydrocephalus,….

-in the second trimaster:-in the second trimaster: Symptoms: hepatomegaly, splenomegaly, Symptoms: hepatomegaly, splenomegaly,

encephalitis, pnemonia,purpura,…encephalitis, pnemonia,purpura,…

-in the last trimaster:-in the last trimaster:     subclinical infection at birth subclinical infection at birth subsequently retinochoroiditis (unless the subsequently retinochoroiditis (unless the

infection is treated).infection is treated).

Histopathology of ToxoplasmosisHistopathology of Toxoplasmosis

Pathology of ToxoplasmosisPathology of Toxoplasmosis

Hydrocephaly & MicrocephalyHydrocephaly & Microcephaly

Retinochoroiditis

Retinochoroiditis, is frequently a result of congenital infection.  Patients are often asymptomatic until the second or third decade of life, when lesions develop in the eye.

Diagnosis of Toxoplasma infectionDiagnosis of Toxoplasma infection

The diagnosis of toxoplasmosis may be documented by:The diagnosis of toxoplasmosis may be documented by:

Observation of parasites in patient specimens, such as:Observation of parasites in patient specimens, such as: bronchoalveolar lavage material, or lymph node biopsy. bronchoalveolar lavage material, or lymph node biopsy.

Isolation of parasites from blood or other body fluids Isolation of parasites from blood or other body fluids

Detection of parasite genetic material by PCR, especially in Detection of parasite genetic material by PCR, especially in detecting congenital infections in utero.detecting congenital infections in utero.

Serologic testing is the routine method of diagnosis, Serologic testing is the routine method of diagnosis,

Microscopy FindingsMicroscopy Findings

Toxoplasma gondiiToxoplasma gondii tachyzoites tachyzoites

  A

Microscopy finding in tissue smearMicroscopy finding in tissue smear

B: Toxoplasma gondii cyst in brain tissue

2- 2- Serological procedures:Serological procedures:

2-1 Sabin-Feldman( Dye test)2-1 Sabin-Feldman( Dye test)2-2 I.F.A test2-2 I.F.A test2-3 I.H.A test2-3 I.H.A test2-4 D.A.T2-4 D.A.T2-5 C.F.T2-5 C.F.T2-6 ELISA test 2-6 ELISA test

3-Detection of parasite genetic material by 3-Detection of parasite genetic material by PCR, especially in detecting congenital PCR, especially in detecting congenital infections in utero.infections in utero.

IFA TESTIFA TEST

A:A: Formalin-fixed Formalin-fixed Toxoplasma gondiiToxoplasma gondii tachyzoites, tachyzoites, B:B: Negative IFA for antibodies to Negative IFA for antibodies to T. gondiiT. gondii..

C:C: Negative IFA for antibodies to Negative IFA for antibodies to T. gondiiT. gondii, polar , polar stain reaction.stain reaction.

AB CA

TreatmentTreatment

    Treatment may be recommended for pregnant women or Treatment may be recommended for pregnant women or persons who have weakened immune systems.persons who have weakened immune systems.  

Before 16th weeks' gestationBefore 16th weeks' gestation– 4 weeks Spiramycine4 weeks Spiramycine

After 16th weeks' gestation After 16th weeks' gestation (Seroconversion, or persistend (Seroconversion, or persistend IgM in the 2nd or 3rd Trimenon) IgM in the 2nd or 3rd Trimenon)

alternating to birthalternating to birth 4 weeks combination of:Pyrimethamin [Daraprim©], 4 weeks combination of:Pyrimethamin [Daraprim©], Sulfadiazin, Folinic Acid Sulfadiazin, Folinic Acid 4 weeks Spiramycine [Rovamycine©]4 weeks Spiramycine [Rovamycine©]

ImmunityImmunity

Concomitant immunity( premuntion )Concomitant immunity( premuntion )

Both cellular & humoral immunity; especially humoral Both cellular & humoral immunity; especially humoral

Play main role.Play main role.

Cellular immunityCellular immunity IL-12 increase Th1 INF- IL-12 increase Th1 INF-γγ

Activate macrophage CD8+ Lysis of infected cellActivate macrophage CD8+ Lysis of infected cell