Learning Objectives Important Protozoan Infections Must Know:
Importance to Kuwait
Diagnostic & Infectious stages
Mode of Transmission Pathology & Clinical Presentation
Laboratory Diagnosis
Prevention
Should Know:
Principles of Management/ Prophylaxis
IQBAL @HSC.EDU.KW
PROTOZOA Unicellular, occur singly/ colony Encyst to survive outside body infective stage
mode of transmission
Reproduce actively fission]
Transmission:
[binary
Important Protozoan Infections G I Infection Amoebiasis Giardiasis
[Entamoeba histolytica] [Giardia lamblia]
Sexually Transmitted Infection Trichomoniasis [Trichomonas vaginalis]
Opportunistic Infection Cryptospridiasis
[Cryptosporidium
Important Protozoan Infections G I Infection Amoebiasis [Entamoeba histolytica] Giardiasis [Giardia lamblia] Sexually Transmitted Infection Trichomoniasis [Trichomonas vaginalis] Opportunistic Infection Cryptospridiasis [Cryptosporidium sp.]
Important Protozoal Infections Vector Borne Infections Malaria [Plasmodium sp.] Leishmaniasis [Leishmania sp.] Zoonotic Infections Toxoplasmosis [Toxoplasma gondii]
Clinical Case# 1 • A 12-year old Indian boy presented at outpatient with fever, acute abdominal pain & diarrhea for 6 days • He was passing loose stools 4 - 5 times/day • There was mucus and sometimes blood in the •Hestool visited India a month ago with his family
His elder brother who works in a cafeteria shop also esented with the same symptoms for 2-3 days but e symptoms were mild
Clinical Queries • • • •
What is your provisional diagnosis? What’s the etiological agent of this infection? How did he get the infection? What’s the significance of travel to India? • How would you diagnose this infection? • How would you manage this patient? Why his brother presented with mild symptoms? Should his brother resume his work at the restaurant? Can this patient or his brother transmit infection to others?
Amoebic Infection Strains:
Entamoeba histolytica Entamoeba coli
Pathogenic Nonpathogenic
Dientamoeba fragilis
Pathogenic (mild)
“ Nonpathogenic strains are known as E. dispar ” All except E. gingivalis live in the large intestine
Free living Amoebae: Acanthamoeba sp.
Naegleria fowleri
Entamoeba histolytica Infection:
700 850 million
Symptoms: 75 100 million (colitis/ liver abscess) Deaths: 50110,000 Invasive Strains: India, Indonesia, Mexico, S. Africa
High Risk Groups:
Institutionized individuals (20 70%) Immigrants Immunocompromized
Entamoeba histolytica
Prevalence very high in Tropics Mode of transmission: Feco-oral; Contaminated food/ water Infective Stage:Cyst ….. Excystation in Duodenum Diagnostic Stage: Cyst and Trophozoite
Trophozoite
Cyst, E. histo
Cyst, E. coli
Microscopy of Stool Smear Habitat: Wall & lumen of Large intestine
E. histolytica Trophozoite
Microscopy of Stool Smear: Cysts Iodine Trichrome staining
E. histolytica
E. coli
Amoebiasis Pathogenesis Approx. 10 cysts can produce infection
Factors: Intestinal flora Diet: Carbohydrate diet facilitates invasion Host immunity Strain virulence
Amoebiasis Pathogenesis
Mechanism: Role of galactose-specific lectin receptors
Role of pore-forming proteins Proteolytic enzymes Activation of alternate complement pathway
Amoebiasis Pathology
Enteritis
Ulcers
Peritonitis
Amoeboma
Hepatic abscess
Flask shaped
Amoebiasis Pathology
Peritonitis
Amoeboma
Hepatic abscess
Clinical Case 2 • A 39-Year old Kuwaiti presented at outpatient with fever & pain in the Right hypochondrium 2 weeks. • He has no diarrhea • His general condition is fine but has lost some weight 2 Months ago: • He visited Mexico 6 months ago • He had diarrhea with mucus & blood • There was no nausea or vomiting
Amoebic Abscess
Investigation
Ultrasound: A cystic lesion in the Right lobe of liver. Differential Diagnosis: Hydatid cyst Amebic abscess Pyogenic abscess Secondaries
Amoebic Abscess Investigation
Amoebic Abscess Investigation Aspirate: viscid chocolate, reddish colored Anchovy sauce Microscopy: Fresh specimen Degenerated liver cells, RBCs
No Neutrophils No pathogen is seen on Gram’s stain
Investigation
I. Stool Exam II. Serology III. Ultrasound
I. Stool Exam:
Direct Stool Exam: Loose, mucus with blood.
Microscopy: Trophozoites : Acute cases
Cysts
Carriers
Investigation III. Ultrasound: Necrotic hepatoma Pyogenic liver abscess Hydatid cyst
•
Additional Tests: Isoenzyme characterization PCR
Management Tissue infection:
Adult
Child
Ist Choice: Metronidazole or Tinidazole
750 mg
50/mg/kg/d
x 10d
2g/d
60mg/kg/d
x 3d
30mg/kg/d
30mg/kg/d
x 10d
20mg/kg/d 30mg/kg/d
x 10d x 10d
30mg/kg/d
x 10d
2nd choice: Paromomycin
Luminal carriage:
Ist choice: Diloxanide furoate 500mg 2nd choice: Paromomycin 30 mg/kg/d or Iodoquinol 650 mg tid
Clinical Queries • • • •
What is your provisional diagnosis? What’s the etiological agent of this infection? How did he get the infection? What’s the significance of travel to India? •How would you diagnose this infection? •How would you manage this patient? Why his brother presented with mild symptoms? Should his brother resume his work at the restaurant? Can this patient or his brother transmit infection to others?
Amoebiasis
(E. histolytica)
Prevalence very high in tropics
•Mode of Transmission: –
Feco-oral
- Contaminated food/ water
Cyst is the infective stage •Pathogenesis: –
Proteolytic enzymes/ Toxins
- Lysis of macrophages
•Pathology: –
Flask shaped ulcers in large intestine
–
Amoeboma,
Peritonitis,
Hepatic abscess
•Presentation: - Carriers
- Mild diarrhoea
- Bloody mucoid diarrhoea
- Abscess
•Diagnosis: - Microscopy [Trichrome staining] •Prevention: Improved personal hygiene
- Serology
You must yield the right-of-way to an approaching vehicle when you are: 1 Already in a traffic circle. 2 Already in an intersection. 3 Going straight ahead. 4 Turning left.
Free Living Amoebae Naegleria fowleri Trophozoite: Amaeboid and flagellate; motile; Infective Cysts: Round; single nucleus; thick double wall Association with water: soil; lakes, ponds, coastal water, fresh water, sewage, Pathogenesis: Acute, H/o swim • through olfactory mucosa • submucosal nerve plexus to CNS
Free Living Amoebae Naegleria fowleri Pathogenesis: Primary Amaebic Meningoencephalitis (PAM) Predisposing Factors: Healthy Pts; Contact with water (H/O swim) Portal of Entry: Olfactory neuroepithelium Incubation Period: 1-15 days; Fatal in 98% Pathology: Necrosis of cortex, Olfactory Bulbs & base of brain
Diagnosis: History: CSF: Examine wet mount (motile trophozoite) IFA:
Treatment: Amphotericin B
Free Living Amoebae Acanthamoeba sp. Trophozoite: Amaeboid and flagellate; motile; Infective Cysts: Thick double wall, outer wall wrinkled Association with water: Bottled mineral water, coastal Fresh tap water, Contact lens wash solution Clinical Diseases: I. Granulamatous amebic encephalitis (GAE) (chronic, no H/o swimming, H/o trauma)
II. Keratitis:
Keratitis, uveitis, corneal ulceration
Free Living Amoebae Acanthamoeba sp. Predisposing Factors: Immunodeficient Pts; AIDS, Chronic Diseae Portal of Entry: Lungs, Skin Incubation Period: Weeks to months; Fatal in 100% Pathology: Multiple necrotic foci in brain
Diagnosis: Direct smears, Cultures of corneal scrapings Stain with Giemsa and Gram.
IFA: Treatment: Prevention:
Clotrimazole, Pentamidine are effective. Amphotericin B is ineffective; Use Ketoconazole
Chlorination of water
Clinical Case •A young boy presented with redness, irritation and watering of Right eye for 7 days • His condition deteriorated and his vision became blurred •The culture of Eye-swab was negative for microorganism •He was advised to use antibiotic eye drops •He has been using contact eye lens since 1 year
Clinical Case 6 weeks later: •The condition of his eye deteriorated further and his vision became blurred •Corneal ulcers developed
Amebic keratitis
You come to an intersection which is blocked by other traffic. You should: 1 Go slowly until the traffic ahead moves. 2 Get as close as possible to the other car. 3 Stay out of the intersection until you can pass through 4 Sound your horn to make the cars move up.
Clinical Case A young boy presented with loose fatty stools alternating with constipation for One month He is not eating well and he has lost 7 Kg There is no mucus or blood in the stools Important Points: * Young boy, loose fatty stool with constipation
Giardiasis Giardia lamblia Prevalence very high in Tropics
Mode of transmission: Feco-oral; Contaminated food/ water Infective Stage: Cyst ….. Excystation in Duodenum Diagnostic Stage: Cyst and Trophozoite
Trophozoite
Cyst, G. lamblia
Microscopy of Stool Smear Iodine Trichrome staining
Trophozoite
Cyst, G. lamblia
Pathogenesis
Uptakes pancreatic bile salts & thus interferes with pancreatic lipase
Giardiasis
Pathology
An Alkaline pH & a rich –CH diet favors multiplication
Mechanical damage of villi
Malabsorption
Fatty diarrhea
Chemotherapy: Quinacrine HCl
Clinical Case A young female presented with vaginal discharge for >5 days The discharge is foul smelling & whitish Microscopy of the discharge showed motile flagellate organism Important Points: * Foul smelling vaginal discharge * Motile flagellate organism on microscopy
Trichomoniasis
Trichomonas vaginalis
Prevalence high in Young Women Mode of transmission: Sexual Infective & Diagnostic Stage: Trophozoite There is No Cystic Stage
Both partners must be treated by Metronidazole
Case Presentation •A Renal transplant patient on immunosuppressive therapy presented with acute profuse greenish watery diarrhea of 5 days duration. •There is no nausea or vomiting •He lost Points: 7 Kg of weight in one week Important * Patient on immunosuppressive therapy
Cryptosporidiosis
Cryptosporidium sp.
Causes profuse greenish watery diarrhoea Associated with Immunocompromized patients Mode of transmission: Feco-oral, contaminated water Infective & Diagnostic Stage: Oocyst [4-5 µ] Special Staining: Acid fast stain (Safranin-Methylene Blue)
Management: Improve hygiene Rehydration Nitazoxanide/ Paromomycin
Cryptosporidium sp.
Cryptosporidium sp.
Pathogenesis
Cryptosporidiosis Pathology
Cellular infiltration of lamina propria
Mechanical damage of villi
Watery diarrhea
Cyclosporiasis
Cyclospora sp.
Causes profuse watery diarrhoea Associated with Immunocompromized patients
Mode of transmission: Feco-oral, contaminated water Infective & Diagnostic Stage: Oocyst [8-10 µ] Special Staining: Acid fast stain (SMB) Oocysts don’t stain uniformly
Management: Improve hygiene Rehydration Trimethoprim-sulfamethoxazole [Septrin 2 BDx7d]
Cryptosporidium sp. and Cyclospora sp.
Cryptosporidium sp.
Cyclospora sp.
Children under age ___ must be secured in an approved child safety seat. Six Three Five Four
Waterborne Protozoan Pathogens
• Naegleria fowleri • Acanthamoeba spp. • Giardia lamblia • Entamoeba histolytica • Cryptosporidium parvum • Cyclospora sp.
Protozoan Infections Causing Diarrhea
• Entamoeba histolytica
Blood/mucus
• Dientameba fragilis
Mild
• Giardia lamblia
Fatty, No blood
• Balantidium coli
Blood/mucus
• Cryptosporidium parvum Greenish watery • Cyclospora sp. Watery
Amoebiasis
(E. histolytica)
Prevalence very high in tropics
•Mode of Transmission: –
Feco-oral
- Contaminated food/ water
Cyst is the infective stage •Pathogenesis: –
Proteolytic enzymes/ Toxins
- Lysis of macrophages
•Pathology: –
Flask shaped ulcers in large intestine
–
Amoeboma,
Peritonitis,
Hepatic abscess
•Presentation: - Carriers
- Mild diarrhoea
- Bloody mucoid diarrhoea
- Abscess
•Diagnosis: - Microscopy [Trichrome staining] •Prevention: Improved personal hygiene
- Serology
Giardiasis
G. lamblia
Prevalence very high in tropics
Mode of transmission – Feco-oral route – Infective stage:
Pathogenesis:
- Contaminated food/ water Cyst
secreting proteolytic enzymes/ toxins ?
mechanical damage of villi
Pathology: Presentation: Diagnosis: Prevention:
Microvilli damage, Carriers, Microscopy
Malabsorption
Fatty diarrhoea [Trichrome staining]
Improved personal hygiene
Trichomoniasis
T. vaginalis
Prevalence high in young women Mode of transmission: sexual intercourse NO cyst stage is present
Pathogenesis: Pathology: Presentation:
Proteolytic enzymes/ toxins ? Multiple small ulcers on vagina/urethra Frothy foul smelling vaginal discharge Itching/ irritation,
Diagnosis: Prevention:
Males are asymptomatic
Microscopy; Motile trophozoites Treat both partners
Cryptosporidiosis
C. parvum
Immunocompromised patients:
Mode of transmission:
Pathogenesis:
associated with AIDS
Feco-oral, contaminated food/ water
Proteolytic enzymes/ toxins ? Cellular infiltration of lamina propria
Pathology:
Villous atrophy
Presentation:
Majority asymptomatic,
Outbreaks
Profuse greenish watery diarrhoea
Diagnosis:
Microscopy of stool smear with SMB stain IFA
(Oocysts)
Management:
Rehydration, Paromomycine
Prevention:
Good personal hygiene