Family of Amoebic Organisms

• Breaks tissue.
• Ulcer + hemorrhage
• Mucus in stools

• Forms flask-shaped ulcers.
• Trophozoites seen inside.

• Red dots (RBCs) indicate erythrophagocytosis.

• In liver, causes anchovy sauce appearance (pus).

• M/c manifestation: Asymptomatic cyst passage

Intestinal Amoebiasis

• Diagnosis
• Stool samples: 3 consecutive days

• Axenic culture medium:
• Pure culture medium.
• No added supplements.
• Example: Diamond medium.
• Diamonds are pure

• Polyxenic medium:
• Requires added supplements for bacterial growth.
• Craige's culture, Nelson medium, Balamuth medium, Boeck and Dr Bohlav medium.

DOC

Morphology and Diagnosis

• Iron Hematoxylin Stain: Used for chromatoid body.

Liver Abscess

Types: Amoebic vs Pyogenic:

Life Cycle of Entamoeba histolytica

• Host: Humans.

• Infective stage: Mature quadrinucleate cyst.

• Transmission: Ingestion (faeco-oral route).

• Lens users in Ophthal
• Acanthameba
• Contact lens misuse
• Dirty contact lens
• Pseudomonas
• M/c/c of corneal ulcer in contact lens users
• Giant Papillary conjunctivitis

• Signs:
• Radial keratoneuritis
• Causes severe Pain
• Ring abscess.
• Pseudodendrites.

• Treatment:
• PHMB 0.02% (DOC).
• (Polyhexamethylene Biguanide)
• Chlorhexidine 0.02%.
• Propamidine 0.1%.

• Note:
• Acanthameba has pseudopods on examination

• Mnemonic: Pseudo (Pseudopodia, Pseudodendrites) guy puts his lens in a can (Acanthameba) → got infected with Ecoli (NANA Ecoli) → Kannu pazhuth cheenju

• He has 6 GF, 2 main (Polyhexamethylene Bi guanide)

• Acute watery diarrhea (<14 days) → Usually viral (norovirus) or toxin-mediated

• Dysentery (blood + mucus) → Shigella, Campylobacter, Entamoeba

• Persistent diarrhea (>14 days) → Giardia, C. difficile, tropical sprue
• Giardia and Meases is a/w Vitamin A deficiency

• "grand old angry man of the intestine (duodenum)".

• M/c parasitic infection worldwide.

• M/c parasite in stool.

• Common in duodenum.

• Small infectivity dose.

Clinical Features:

• Classical malabsorption (duodenal involvement)

• Fat malabsorption (steatorrhea)
• Bulky, frothy, foul-smelling stool

• Vitamin B12, folic acid, protein deficiencies

Lab Diagnosis:

• Sample: 3-day consecutive stool sample.

• Microscopy: Cyst and trophozoite forms seen.

• Trophozoite:
• 2 nuclei.
• 4 pairs of flagella (8 total).
• Pear-shaped / tennis racket shape (front view)
• Sickle-shaped (side view)
• Falling leaf motility.
• Floats in the lumen.

• Cyst:
• 1-4 nuclei.





 

• String test (Entero-Test):
• String into duodenum for microscopy.
• Put string to catch dadaji in duodenum

Duodenal biopsy:

• Organisms hang in lumen.

• Appear sickle-shaped.

Treatment:

• Drug of choice: Metronidazole.

• Tinidazole: single 2g dose.

• Most common cause of STD and NGU.

• Infective stage: Trophozoite only.

• Diagnostic stage: No cyst formed.

• In males
• Cystitis, Prosthetitis, Urethritis

• Females: Strawberry cervix, greenish discharge.

 

• South delhi fashionable aunti → has No sister (No cyst) → love diamond () and strawberries () and lash () → jerk and twitch ()

Trophozoite:

• Pear shaped

• 1 nucleus.

• 4 anterior flagella.

• 1 posterior flagellum with an undulating membrane.

Diagnosis:

• Shows twitching / jerky motility.

• Sample: Discharge sample.

• PAP smear can be used.

• Microscopy: Only trophozoites.

Culture:

• Lash cysteine hydrolysate serum

• Diamond medium.

Treatment:

• DOC: Metronidazole.

• Partner must be treated.

Parasites Causing Myocarditis

• T.B. Rhodesiense

• Trypanosoma Cruzi

• Trichinella Spiralis

• Echinococcus

• Toxoplasma gondii

• Mnemonic:
• KLLL → kaLa azar → Leishmaniasis → LAMB
• Pro (Promastigote) causes infection

• Etiology:
• Wuchereria bancrofti (Most common)
• Brugia malayi
• Brugia timori

• Clinical Presentations:

Type	Characteristics
Cutaneous	Most common, darkening of skin
Visceral (Kala Azar)	Hepatosplenomegaly
Mucocutaneous	Most disabling

• Vector: Phlebotomus argentipes (Sand fly)



• Hairy & Lanceolate shaped wings
• Does not fly
• Hopping range: 50 yards
• Painful biter, nocturnal
• Sand fly : Killed by synthetic pyrethroid.

• Infective Form: Promastigote.

• Diagnostic Form: Amastigote.
• L.D bodies → amastigotes.

Sample:

• Spleen → most sensitive

• Bone Marrow → most preferred

• Blood.

• HIV patients
• BAL
• Spleen and liver → are not very commonly involved

Hypergammaglobulinemia tests:

• Napier's aldehyde test.

• Chopra's antimony test.

Diagnosis:

• Montenegro test
• Kala → black → negro

• Media: NNN (Novy-MacNeal-Nicolle) media → shows promastigotes
• NNN media also used for
• T. cruzi.
• Leishmania

• Serology: rk-39 antigen (rapid card test).

• PCR → definitive test

Treatment:

• Liposomal Amphotericin B: DOC (single dose)

• Alternatives
• Miltefosine
• Paramomycin

Parasites Causing Myocarditis

• T.B. Rhodesiense

• Trypanosoma Cruzi

• Trichinella Spiralis

• Echinococcus

• Toxoplasma gondii

• Consequence of visceral leishmaniasis

• Develops 1-2 years after treatment.

• Presents as hypopigmented nodules.

• History of kalazar (fever, splenomegaly, hepatomegaly) in childhood

• Develops years later

• Caused by: L. Infantum, L. Chagasi, L. Donovani

• Endemic to NE India

• Lesions:
1. Raindrop-like hypopigmented lesions on trunk
2. Succulent erythematous papules and nodules around muzzle area of face

• Not leprosy (no loss of sensation)

Smear:

• Leishman in Donovan bodies
• LD bodies, amastigote form in macrophages

Treatment:

• DOC: Oral Miltefosine

• Antimonials,

• Amphotericin B,

• Primary toxoplasma infection during pregnancy.
• Severity → more if affected earlier (11 weeks)

• Mnemonic: Toxic killing → Kanni kude (chorioretinitis) thalayilott (cerebral calcification) inject cheyth (↑ size → hydrocephalus)

• Definitive host: Cat.

• Intermediate host: Human.

Mode of transmission

• Ingestion
• Sporulated oocyst via contaminated soil/food/water.
• Bradyzoites via undercooked meat.

• Blood transfusion & Vertical
• Tachyzoites.

• Blood and sex - tachy

• Relax (Brady) and eat meat
• Beef - brady

• spores from soil

• Cat → Oocyst
• Infective Stage.
• Diagnostic Stage.

• Diagnosis
• Serological diagnosis.
• Direct identification of parasite from:
• Peripheral blood.
• Amniotic fluid.
• Tissue sections.

Variants of toxoplasmosis

• Adult toxoplasmosis
• Asymptomatic.
• LN enlarged.

• HIV+ toxoplasmosis
• Encephalitis.
• Most commonly brainstem is affected.

• Congenital Toxoplasmosis
• More severe in trimester I.
• More common in trimester III.
• Chorioretinitis.
• Intracerebral calcification.
• Convulsions.
• Microcephaly
• Mental retardation.



• Mnemonic: CHC
• Small for gestational age.
• Prematurity.
• Hydrops fetalis, i.e., generalized anasarca.
• Persistence jaundice.
• Thrombocytopenia.
• Focal Chorioretinitis
• Most common manifestation
• HYDROCEPHALUS.
• Macrocephaly due to hydrocephalus.
• Cerebral calcification
• On NCCT

Important Information

• Toxoplasma → intracerebral calcification.

• CMV → periventricular calcification.

Diagnosis

• Frenkel test

• Sabin Feldman test: Gold standard.
• Test uses Methylene blue and tachyzoite stage
• If colorless - antibodies present.
• If color is present - antibodies absent.

Prevention and Treatment

• Pyrimethamine + Sulfadiazine.

• Early diagnosis of infection

• Treatment of mothers is by sulphadiazine.

CD4 Count vs Opportunistic Infections

CD4 Count	Infections/Findings	ㅤ
~600	• Lymph node enlargement	6 swellings → LNs
~500	• Herpes Zoster Virus • Pneumococcus (lobar consolidation)	ㅤ
~400	• Kaposi Sarcoma (any CD4) • Tuberculosis (snowstorm/hazy)	4K TB
~300	• Oral Hairy Leukaemia	300 Hairs
<200	• PCP (perihilar opacities), • Miliary TB, Candida, Cryptosporidium • Mucocutaneous Herpes	ㅤ
<100	• Cerebral Toxoplasmosis, • Cryptococcal Meningitis, • CNS Lymphoma, HIV Dementia, PMLE	100 = Brain
< 50	• CMV Retinitis • MAC	ㅤ

Congenital toxoplasmosis CT

• Eccentric target sign.
• M/c site: basal ganglia

• Most common infectious cause

• Mnemonic: Toxic guy () saw a headlight in a fog () and got a punch ()

Cryptococcosis:

• Soap bubble appearance.

• Cry when bathing with soap

CNS lymphoma:

• Solitary enhancing peripheral lesion.

• If “V” present → Very active in liver

• Schizont hide in cerebral blood vessel

Immunity Against Malaria

• Duffy & Basigin Antigens.

• Some humans immune- lack Duffy antigens

Immunity scenarios

• SC traits.

• Thal Trait.

• Fetal Hb.

• G6PD deficiency.

• Ovalocytosis.

• Absence of Duffy antigen.

Light Microscopy (IOC)

• 1 microscope / 25,000 population

• Gold standard.

• Peripheral Blood Smear
• Thick Smear:
• Identifies parasite
• For quantification of malaria.
• Sensitivity - 5 parasites /microlitre.
• Thin Smear:
• (tongue-shaped smear)
• Identifies species
• Sensitivity - 200 parasites/ microlitre.

• Stains used - Romanowsky stain.
• JSB: Jaswant Singh Bhattacharji (JSB)
• or Giemsa

• 200-300 OIF (Oil immersion field — 100x) examined
• before reporting negative.

• Vivax and ovale affect and enlarge young RBCs.

• All other plasmodium involve all RBCs.

Other Laboratory Diagnosis

• PCR: Most sensitive test.

• Fluorescent microscopy:
• Rapid screening, expensive.
• Kawamoto technique: acridine orange.
• The screening method of choice.

• Microhematocrit method.
• QBC: Quantitative buffy coat.

• RDT-Rapid diagnostic test/card test.

Malarial pigment:

• Haemoglobin changes to Hemozoin - yellow-brown pigment.
• Property of all plasmodium.

• Under a microscope: Trophozoite, Schizonts and Gametocytes are observed.

QBC: Quantitative Buffy Coat analysis

• Blood is taken and spun
• RBC at the bottom.
• Plasma at the top.
• Tiny middle area - called Buffy Coat.
• All organisms stay at the buffy coat - malaria, filaria.
• Sensitivity is 2 parasites/microlitre blood.
• Fluorescent dye coated tube - Acridine orange stain.

RDT: Rapid diagnostic test/card test

• Principle = Immunochromatography (ICT)

• Sensitivity = 50-100 parasites/microlitre.

• Nitrocellulose membrane.

• Control line — validation line.

Field test:

• All malaria species have aldolase and LDH.
• ALL → Aldolase & LDH

• P.falciparum has histidine rich protein 2— HRP2.

ACT Components:

• Artesunate: 4 mg/kg

• Sulfadoxine: 25 mg/kg

• Pyrimethamine: 1.25 mg/kg

• Artemether: 20 mg

• Lumefantrine: 120 mg

• Mnemonic: NES → Not SP (swayam pongi)

• Mixed Infection
• (P. falciparum + P. vivax)
• Rx: ACT-AL/ACT-SP + Primaquine x 14 days

In Pregnancy:

Complicated / Cerebral Malaria

• IV Quinine

• IV Artesunate

Primaquine

• DOC for Radical Cure For P. vivax

• Given for 14 days

• Tafenoquine is single dose radial cure of P. vivax malaria

• Contraindication (C/I) of Primaquine:
• Pregnancy
• Infants
• G6PD deficiency

Vaccines

• Mosquirix RTS

• S/AS01

Prophylaxis

Indicators

• Incidence → x 1000

• Rate → x 100

• Annual Parasite Incidence (API):

Category	API (State)	API (District)	Classification
3	>1	-	Intensified malaria control
2	<1	Some : >1	Pre-elimination area
1	<1	All : <1	Elimination area
0	0 or negligible	-	Prevention of re-establishment

• Count 3 - 2 - 1 - 0 → kill the mosquito
• Assesses the burden of malaria
• Impact indicator
• Total no of confirmed cases x 1000
  Total population
• Confirmed cases:
• Slides positive OR
• Rapid diagnostic kit positive (Approved only in NES)

• Annual Blood Examination Rate (ABER) (> 10%):
• No of slides examined x 100
  Total population
• Indicator for prevalence of fever
• Operational indicator

• Slide Positivity Rate (SPR):
• No. of slides positive x 100
  No. of slides examined
• Best during outbreak

• Recent Malarial Transmission Indicator:
• Infant Parasite Rate (IPR)

• Number of slides examined → always 100

• Spleen Rate
• Number of children from 2 to 10 years showing enlargement of the spleen.
• Measure of endemicity of malaria.
• Holoendemic pattern - seen during 2- 10 years

• Maltese cross appearance
• Babesiosis
• Fabrys disease
• Nephrotic syndrome

Operculated Eggs

• Has a thin cap on top (lid).

• Mnemonic: STD.
• S - Spirometra.
• T - Trematodes.
• Exception: Schistosoma (Spinous egg).
• D - D. Latum.

L3 is infective form in

1. D. Latum

2. Draculunsis

3. Lymphatic filariasis

Neurocysticercosis

• Soli sir affect brain → he is sole cause (sub kuch infective - egg and larvae) → Nakshathram enni (starry sky)
• he was Para (Parenchyma brain)
• solium - systi sercus sellulose → inside the cell

• Cysticercus cellulosae:
• zig-zag tube, hooklets, suckers, convoluted tube-like structure

• Scolex in brain.

• M/C site : Brain parenchyma

• M/C presentation: Seizures

• Imaging: Gadolinium MRI preferred.
• Starry sky appearance

• Drugs: Steroids f/b Albendazole (DOC)
• ↓ inflammation d/t dying larvae

Layers of hydatid cyst

• Echi → Casino (casoni) ilu chuuthu kalich → 5 alkk (5 Arc) paisa kodukkkanam → Olichirun (Hide - hydatid cyst) → in water lillyy → Dog ne bite cheyyich → first liver then lungs

Classification (WHO-IWGE 2001 / Gharbi 1981 USG based):

• Echinococcus granulosus → Granny kk ekkili eduthu (Echinococcus gran) → CBSE 3rd std Appu (3a) → 2 (Type2) Lilly (water Lilly) kondu koduthu

Treatment of Echinococcus granulosus

• First line: Albendazole

• PAIR Process:
• P - Puncture of cyst.
• A - Aspirate.
• I - Injection scolicidal agent
• R - Re-aspiration.

• Scolicidal agents:
• Hypertonic saline (M/c),
• Cetrimide,
• Mebendazole
• Alcohol.
• Note: Formalin not used (causes chemical cholangitis).

• Contraindications (C/I) for PAIR:
• 4 and 5
• Cystobiliary communication
• During aspiration, if bilirubin level positive
• DO NOT INJECT SCOLICIDAL AGENT
• Dead cyst, Calcified cyst, Extrahepatic cyst.
• Deep seated, Multiloculated.

• Surgery: 
• Done if PAIR is C/I
• Liver resection or cystopericystectomy

Echinococcus multilocularis:

• Multilocular AKA alveolar hydatid cyst.

• M/C site: Liver.

• Second M/C site: Lungs.