1. Vector-borne zoonotic disease caused by genus
leishmania that is obligate intracellular protozoa
Vectors – Phlebotomus and Lutzomyia
Zoonotic form, dogs as main reservoir, occurs in
the Mediterranean basin, China, the Middle East,
and South-America; cause is L. infantum.
The anthroponotic form, humans as reservoir, is
caused by L. donovani ; prevalent in East Africa
and the Indian subcontinent.
Major forms: Visceral, cutaneous and mucocutaneous
5. Risk of acquiring infection is determined by local
sand fly behavior and by the presence of an infected
animal or human reservoir
Transmission
Female sand flies (Phlebotomus and Lutzomiya
Spp.) get infected after sucking blood from infected
reservoir eg. human or other mammals
Amastigotes transform to promastigotes in sand fly
gut Replicating and metacyclic promastigotes are
regurgitated and injected into the skin during
subsequent blood meal
6. Other route of transmission are via
blood
Shared needles
Blood transmission
Trans-placental spread
Via organ transplantation
7. Population at risk – 350 million
Over all world prevalence – 12million
Annual new case reports – 2 million
About 90 countries affected
More than 20 spp of leishmania identified
VL in 70 countries,
S. Asia 600,000 cases in 2006 – significantly
decreasing due to control measures
East Africa 30,000 (mainly Sudan, Ethiopia)
Brazil 4,000
9. lowlands of Ethiopia with varying endemicity.
N West. - Metema and Humera, Wolkayit,
Libo/Fogera
N East – Ethio-Djibouti Awash Valley
S. West – Segen, Dawa, Genale, Woito, Konso,
Omo, Gambella Sudan border
40 localities and new foci are being reported.
Main risk factor - population migration
Estimated annual VL – 4500-5000 people
10. VL cause - by species of the Leshmania
donovani complex - L. donovani
The sand fly - Phlebotomus orientalis,
Phlebotomus martini and Phlebotomus celiae.
Animal reservoirs are suspected, but not
documented yet.
11. 11
VL- HIV co-infection rate at Humera
1998/99 – 18.5%
2006 – 40%
A Tigray retrospective review of 791 cases
showed >4x CFR in HIV + VL patients than VL
without HIV.
Libo – HIV –VL coinfection rate 15-18%.
12. More than 90% of the world's cases of
cutaneous leishmaniasis occur in Middle East
(Old World) and in Brazil and Peru (New
World).
The etiologic agents are L. tropica, L. major,
and L. aethiopica (Old World) and species of
the L. mexicana complex and the Viannia
subgenus (New World).
13. 13
T cell Response
Th 1 pattern Response
Th 2 pattern Response
T lymphocyte release IL-2 and INF gamma
Ineffective humoral response
Effective cellular response
Activates macrophges to kill Leishmania
Leishmainin skin test positive, but no clinical VL
T lymphocyte release IL-4,IL-5,IL-10,
TNF - B
Inhibit macrophage from killing Leishmania
High Antibody level and Clinical VL
IL
4
&
10
-
14. Depends on – Parasitic properties (Infectivity,
pathogenicity and Virulence)
Host factors and host responses
Manifestation range from asymptomatic, self
healing cutaneous leishmaniasis to diffuse
cutaneous and visceral disease
15. Presentation
Kala-azar (Black fever in Hindu)
IP: Wks –Mo’s
Often remains asymptomatic
Symptomatic cases: acute, sub acute or chronic
course
Fever, night sweats, weakness ,weight loss
Cachexia, wasting, Pallor
Nontender, soft massive splenomegaly +
perisplenitis
16. Hepatomegaly + LAP
Darkening of face/ashen grey appearance
Bleeding 20 to thrombocytopenia
Susceptibility 20 infection
Pancytopenia (Anemia, Thrombocytopenia,
Leukopenia, Neutropenia)
Marked eosinopenia, Reactive lymphocytosis,
Monocytosis
Hypergammaglobulinemia
Hypoalbuminemia
17.
18. Gold-standard: Demonstration of amastigotes
in tissue aspirates
Diagnostic sensitivity – Spleen - > 95%; Bone
marrow 70%, Lymph nodes 58%
DAT test: Anti-Leishmanial (titer) IgG sn >95%,
sp >90%
Detection of Anti-rK39-Abs Sn 72%, Sp 82%
Culture – NNN media
Isoenzyme and molecular techniques to
differentiate species
19.
20. SSG + Paramomycin for 17 days
Sodium stibogluconate (SSG) 20mg/kg iv/im for
30 days
Alternative:
AmBisome 4mg/kg for 5-7 doses: 1-5days, 10th, 14th.
Amphotericin B 1mg/kg every other day for 30
days/total 15 doses.
Single dose AmBisome not effective in N Ethiopia
Other drugs but less effective:
Paramomycin, Pentamidine, Miltefosine (oral prep)
Secondary prophylaxis (in HIV)- ?? Pentamidine
21. Clinical improvement after 7-10 days in majority
Apparent cure response (Afebrile, splenic size,
no visible amastigotes on repeat splenic aspirate
within 2 weeks of Rx in > 90% of cases
Hematologic abnormality improvement by 4th
weeks of Rx
Splenomegaly disappear < 6 months after Rx
22. Reactive skin test + ve < 1 yr after Rx
No response or death : 5-10%
Relapses after apparent cure: 5-10% (often < 6
months after Rx)
Cure documented after 6 months of Rx
completion (-ve splenic aspirate for leishmania
i.e. test of cure)
23. New infection or Reactivation (>95% of co-
infection reports are of VL)
Less virulent leishmania spp cause VL.
Most patients with CD+
4 count <200/l
Widespread atypical organ involvement eg GIT
Frequent parasitemia, high yield from buffy coat
Peripheral blood 50%, buffy-coat culture 70%
24. Sub optimal specific IgG production
Lower diagnostic sensitivity to serologic tests
(50% Vs >90%)
High rate of relapse / drug toxicity
Reduced responsiveness to tx (comparable
initial response)
HAART- incidence of clinical leishmaniasis
25. Demonstration of amastigote forms on geimsa
or wright stain
method VL with out HIV VL with HIV
spleen 93-99%
Bone marrow 53-86% 67-94%
Lymph node 53-65%
Buffy coat / BF ~ 30% 50- 53%
DAT 95-97%* 95% in Ethiopia; 89-90%
rK39 93-100%* 22-62%
26. IP =Weeks - Months
Start as a papule at the site of insect bite and
evolve to nodules, ulcer, plaque
It may complicate with regional adenopathy,
sporotrichoid subcutaneous nodules, lesion
pain or pruritis, 20 bacterial infection
The infecting spp, the location of lesion and
the host immune response determine the
manifestation and chronicity of the lesion
27.
28.
29. Visualization of amastigote in Giemsa-Stained
thin smear from dermal scraping /biopsy
specimen.
Serology tests – insensitive
Indication for treatment
Persistent lesion ( > 6 months)
Lesions that are located over joints
Multiple lesions (> 5 to10 in number)
Large lesions (> 4-5cm)
31. Presentation: - Erythema and ulceration of the
nares Nasal septal perforation and
destructive inflammatory lesion
obstruction of pharynx/larynx and remarkable
disfigurement.
Treatment
IV/IM SSG therapy, Amphotericin B
32.
33. Etiology:- Entamoeba histolytica
Epidemiology: Transmission and cycle
E. histolytica acquired by the ingestion of infectious
viable cysts from feces contaminated water, food or
hands Release of motile trophozoite from cysts in
small intestine
Large bowel mucosa invasion with sub mucosal
extension Inoculation of amoebas in to the portal
system distant metastatic abscess in liver
/lung/brain Encystation of trophozoites and/or
motile trophozoites passage in stool.
35. Toxic megacolon :- Bowel dilation with intra-
mural air
predisposing factor: - Glucocorticoid treatment
Chronic amoebic colitis - DDX: IBDs
? Post amoebic colitis
Bowel perforation
GI bleeding
36. Acute presentation in young pts with prominent
symptoms <10 days
Chronic /sub acute presentation in older pts with
hepatomegaly /Wt loss/anorexia > 6 months
Pathology : “ Anchovy paste”
Fever – possible cause of FUO (10-15%)
RUQ pain + Hepatic point tenderness
Rt. Sided pleural effusion
Preceding active diarrhea (<30%)
39. 1. Stool examination
Microscopic fecal findings: Wet mount
+ve test for heme
Paucity of neutrophils
Amoebic cysts or hematophagous trophozoites of
E.histolytica
2. Serologic test for invasive amoebiasis
ELISA
Agar-Gel diffusion assay
+ve in >90% of pts with colitis /Amoebomas/liver
abscess
40. 3. Liver imaging - US/CT scan/MRI for oval /round
hypoechoic cyst
>80% who had Sxs >10 days –single abscess in rt.
lobe
50% who had Sxs <10 days –multiple abscesses
Findings favoring complications
Large abscess (>10cm)
Abscess in superior part of rt. lobe
Multiple abscesses
Abscess in left lobe
41. 1. Intestinal amoebiasis
Asymptomatic carriers: Luminal agents – Iodoquinol
650mg tid/20 days, or paromomycin 500mg tid
/10days
2. Acute Colitis
Metronidazole 750mg po/iv for 5-10days + luminal
agent
3. Amoebic liver abscess
Metronidazole 750mgtid/5-10days or Tinidazole
2gmpo or Ornidazole 2gmpo plus luminal agent
42. Need to R/O Pyogenic abscess (in multiple
hepatic abscess)
Failure to respond clinically within 3-5 days of Rx
The threat of imminent rupture
Prevention of left lobe abscess rupture into
pericardium
Surgery
Bowel perforation
Abscess rupture into the pericardium
/peritoneum/ pleural space
43. Adequate sanitation + Eradication of cyst
carriage
Avoid unpeeled fruits/vegetables
Use of bottled water
Water disinfection by iodination
47. Infected snails in fresh water release infective
cercariae
Cercaria penetrate intact skin (they have
anterior and ventral sucker) – in the skin form
schistosomula (morphologic, membrane and
immunologic transformation) from trilaminar to
hepatolaminar membrane adaptive mechanism
for survival in humans.
48. Mature forms migrate to specific sites –
intestine, vesicle – mate and gravid females
travel retrogradely in veins and deposit their
eggs in small veins
Eggs reach intestinal lumen aided by enzymes
and are voided in stool and urine - miracidum
About 50% are retained in host tissue and
flow to liver and other tissues
49. Prevalence starts from age 3-4 yrs and peaks at 15-
20 yrs and decline with older age
Infect 200–300 million individuals in South America,
the Caribbean, Africa, the Middle East, and
Southeast Asia
HIV and schistosomiasis - fewer eggs in their stools
than those infected with S. mansoni alone for
unknown reasons
Treatment with praziquantel may result in reduced
HIV replication and increased CD4+ T lymphocyte
counts
50. Ethiopia – prevalent around Lake Tana,
tributaries of Blue Nile, Awash; Adwa area
Associated with the water use
51. Dermatitis/swimmer’s itch – popular pruritic
rash at skin penetration site in 24-48hrs
Katayama fever – serum sickness like illness
associated with excess antigenemia and
formation of soluble immune complexes
52. Eggs retained in host tissues – presinosoidal in
the liver
Cell-mediated granulomatous response around
the ova regulated both positively and negatively
by a cascade of cytokine, cellular and humoral
responses
Granuloma formation begins with recruitment of
a host of inflammatory cells in response to
antigens secreted by the living organism within
the ova
54. Fibrosis of the portal veins can occur and result
in periportal (Symmers' clay pipe–stem) fibrosis;
local or diffuse
Portal HTN results in ascitis, splenomegally and
esophageal varices
Similar pathologic changes occur in the bladder
and results in granuloma formation,
polypomatous growth that can ulcerate and
bleed, obstructive uropathy, urosepsis, risk of
bladder ca
55. Lung – pulmonary HTN and corpulmonale
Brain and spinal cord affection by granuloma
and neurologic manifestation is possible eg
transverse myelitis
GIT – bloody diarrhea and abdominal pain
With concomitant HBV and/or HCV infection
can lead to significant deterioration and
cirrhosis of the liver
56. Swimmer’s itch – typical history contact hx, several
DDx.
Katayama fever - peripheral blood eosinophilia, and
a positive serologic assay for schistosomal
antibodies: the Falcon assay screening test/enzyme-
linked immunosorbent assay (FAST-ELISA) and the
confirmatory enzyme-linked immunoelectrotransfer
blot (EITB). Some have ova in stool.
Chronic cases – detection of ova in the stool, urine.
Kato thick smear or other concentration method.
57. Antipruritic agents for local lesions
Supportive care and glucocorticoids for acute
severe illnesses
Praziquantal (20mg/kg in 2 divided doses)
effectiveness - 85% parasitological cure and
90% egg reduction.
Hepatomegally and bladder lesions also
regress with early treatment but established
fibrosis persists.
58. Avoid contact with fresh water sources in
endemic areas be it fast or slow flowing
Skin topical agents
Molluscicides – eg. Lemma toxin (Aklilu
Lemma from “endod”)
Safe water supply
Follow up of exposed individuals.
59. History is important for dx
Epidemiology, occupation, travel
Life cycle of major parasites
Specimen collection
60. Helminths & protozoa
Excreted by feces - Collection on clean card
board
Avoid water contamination
Take before contrast medium or anti diarrhea
agent intake
3 specimens on alternative days
Polyvinyl alcohol preservation for transport
(for protozoa trophozoits)
61. Macroscopy - nature of stool
- segments of Taenia / motility
- Ascaris worm
Microscopy - with wet mount (saline, dilute
iodine)
Concentration methods:
formalin ether sedimentation (all sediment -
preference
zinc sulfate flotation ( not all float )
Stains
Iron hematoxylin, Trichrome
62. Amoebic liver abscess - trophozoites in the abscess
wall
S. haematobium - in urine sediments
Malaria; leishmania; Trypanosoma - in blood and
lymphoid tissues
Pneumocystis carinii - silver stain of bronchial
aspirate
Onchocerciasis - skin snips
Schistosoma mansoni - rectal snips
Cutaneous and muco-cutaneous leishmania - punch
biopsy
63. Eosinophilia - in trichinosis & Migratory phase
filariasis
Pulmonary migration of larva's of intestinal round worms
Not common in protozoal infections except isospora &
Dientamoebe fragilis
HCMC anemia - in hook work infection
Portal HTN - in Schistosomiasis
Anemia, thrombocytopenia in Malaria, VL
cysts, mass lesion, ring enhancement ......on radiologic
examination (CT, US) in hydatid cyst, toxoplasmosis of CNS....
64. Limitations - for individual pt use
- cross rxn
- not distinguish current & past infection
Negative result rules out infection
Molecular Teachnology PCR - for T. vaginalis
(in USA)
65. Cestodes /flat worms
Intestinal Parasite stage Specimen Remark
T. Saginata ova/segment feces Motile segments
H. Nana Ova "
D. Latum Ova/ segmenta " Megaloblastic
T. solium ova/segment " non motile
cysticercus muscle/CNS CT/MRI
Treatment
-Niclosamide
-Praziquantal
-Albendazole
66.
67. somatic
Echinococcus hydatid cyst liver/lung US/X-ray/CT
liver flukes/F. hepatica ova feces/bile cirrhosis/portal hpt
Blood flukes
schistosoma mansoni ova/adult feces rectal snip, liver bx
S heamatobium ova/adult urine bladder biopsy
Treatment
Echinococcus - long term Albendazole, surgery
Schistosomia _ praziquantel
68. Round worms
E. vermicularis/pin worm ova perianal skin scotch tape test
T. trichiuria/wipe worm ova feces rectal prolapse
Ascaris lumbricoids ova " pulm. migration
Hook worm ova " " "
S. stercolaris larva feces/sputum diss. in HIV
Hookworm
ova
Ascaris ova
