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12/7/2015

SCHISTOSOMIASIS,
ONCHOCERCIASIS, LESHMANIASIS
AND ACTINOMYCOSIS
By

Dr. O.O. Olaofe
(MBBS, MWACP, FMCPath)

• S.mansoni: geographical distribution.
S.mansoni is endemic in 43 countries in Africa
and occurs in the americas in Brazil,
Suriname, Venezuela and in the Caribbean.

SCHISTOSOMIASIS

Schistosoma spp.: cercariae are the infective forms.
They measure about 500 micron. After
encountering the skin,
the cercariae penetrate and lose the tail
transforming into schistosomulae.














White pinhead sized granulomas
Calcification
Infl cells
Darkened liver from regurgitated haem pigments –like
malaria
Patches and pseudopolyps
Bumpy liver
Pipestem fibrosis – no regenerating nodules
Portal hypertension
Congestive splenomegaly
Oesophageal varices, Ascites
Granulomatous pulmonary arteritis, intimal hyperplasia,
cor pulmonale
Membranous and mesangioproliferative GN

• S.mansoni: adult schistosomes live in pairs
in the portal system and in the mesenteric venules;
males are shorter (7-12 mm in lenght and 2 mm wide)
and have a ventral infolding from the ventral sucker
to the posterior end forming the gynecophoric canal.
Adult male with female in the copulatory groove.









• S.mansoni: intermediate host of S. mansoni are snails of the genus
Biomphalaria. Releases ciliated miracidum larva
• Slow moving water – slow flowing rivers, tropical lakes, irrigation
ditches

• Acute schistosomiasis can be a severe febrile
illness that peaks about 2 months after
infection.
• Chronic Schistosomiasis can manifest as
severe hepatic fibrosis.
• Immune response to S. mansoni and
japonicum is responsible for the most
important complications.

S haematobium

Inflammatory cystitis
Granulomas
Mucosal erosions
Haematuria
Calcify and sandy appearance
Ureteral obstruction – Obstructive uropathy
SCC

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12/7/2015

• S.mansoni:

– hepatosplenic schistosomiasis
occurs in S.mansoni and
S.japonicum infections;
– it results by eggs embolization
in hepatic venules with
formation of granulomas and
portal fibrosis.
– hepatosplenomegaly, bleeding
oesophageal varices and
hepatic insufficiency are the
more severe manifestations.

• O.volvulus: geographic distribution.
onchocerciasis occurs especially in Tropical Africa,
between the 15° north and the 13° south (high endemicity in B.Faso and
Ghana).
Foci are present in Southern Arabia, Yemen and in America
(Mexico, Guatemala, Colombia, Ecuador, Brazil, Venezuela).

Pupae of Simulium

The infection is transmitted by several species
of black flies of the genus Simulium.

(Section of an adult female).

Onchcerciasis

• Caused by a filarial nematode.
• Leading cause of preventable blindness
• Affects 18 million people in Africa, South
America and Yemen.
• Habitat – near fast moving water (River
blindness)
• Adult parasites mate in the dermis
(Onchocercoma)

Larva of Simulium

• O.volvulus: the larvae enter the host tissues,
and develop to adults in subcutaneous nodules in about 1 year.
Nodules are usually found in the upper part of the body in the american
onchocerchiasis and in the pelvic region in the african form.

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12/7/2015

• Inseminated females produce microfilariae which can be
disseminated to the eye
• Leopard skin
• Lizard skin
• Elephant skin
• Micro – foci of epidermal atrophy,
elastic fibre breakdown, hyperkeratosis, hyperpigmentation, dermal
atrophy, fibrosis,
Subcutaneous Onchocercoma – Infl cells
Eye lesions- Punctate keratitis, small fluffy opacities of the cornea,
sclerosing keratitis,
Anterior chamber- Iridocyclitis, glaucoma. Involvement of choroid and
retina results in atrophy and loss of vision.

LEISHMANIASIS

• It is a chronic inflammatory disease of the
skin, mucous membranes, or viscera caused
by obligate intracellular, kinetoplastcontaining protozoan parasites transmitted
through the bite of infected sandflies.
• Promastigote – dev and lives extracellularly in
vector
• Amastigote – macrophages
• Reserviors – Rodents, dogs and foxes

• VISCERAL LEISHMANIASIS

• Cutaneous disease

– Old world – L major, L tropica
– New world – L mexicana, L braziliensis

• Mucocutaneous disease (espundia)
– New world – L braziliensis

• Visceral disease –Liver, spleen and bone
marrow
– Old world – L donovani L infantum
– New world – L chagasi

MUCOCUTANEOUS LEISHMANIASIS

– Moist lesions (maybe ulcerating) in nasopharynx
– May be destructive
– Mixed infl cells – plasma, lymphocytes, parasitefilled macrophages












Hepatosplenomegaly (spleen up to 3kg),
lymphadenopathy,
Pancytopenia, fever, weight loss
Fibrotic liver in late stages
Increased phagocytic cells in bone marrow, lungs, GIT,
kidneys, pancreas and testes
Hyperpigmentation of skin (Kala azar)
Mesangioproliferative GN
Amyloid
Secondary bacterial infections –pneumonia, sepsis
and TB
Haemorrhages due to thrombocytopaenia

CUTANEOUS LEISHMANIASIS

– Relatively mild
– Ulcers on exposed skin
– Papule surrounded by induration --- shallow
expanding ulcer – heals within 6 to 18 mths
without Tx

• Micro –

– granulomas, many giant cells, few parasites.

DIFFUSE CUTANEOUS LEISHMANIASIS

– Rare, found in East Africa, Central and south
America
– Widespread skin nodules
Visceral leishmaniasis has a wide geographic distribution.
North-Eastern China, India, Middle-East, Southern Europe
(Mediterranean bassin),
Northern Africa, Central-East Africa and, in foci, Central
and South America (especially Brazil and Honduras).

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12/7/2015

• The infection is transmitted by various species of Phlebotomus, the sand
fly.



Diagnosis of the infection depends on identification of amastigotes in tissues
(bone marrow, spleen, liver, lymph nodes) or in blood.
Other organs may be affected, expecially in HIV-1 positive patients
(intestinal and respiratory tract).
Amastigotes can be found inside and outside the reticuloendothelial cells.
They measure 2-5 µm, are oval with a large nucleus (in red), a kinetoplast
(usually perpendicular, in red to violet) and a pale blue cytoplasm.
(Bone marrow aspirate).

• Leishamnia spp. which affect humans can be differentiated by
geographical distribution, clinical spectrum, immunological
features, isoenzymes and Kinetoplast DNA (kDNA)
characterization.
(LEISHMANIA AMASTIGOTES, BONE MARROW ASPIRATE, GIEMSA
STAIN).

• Visceral leishmaniasis: liver biopsy can
demonstrate the Leishmania amastigotes
inside the reticuloendothelial cells. The hepatic
structure is preserved.

ACTINOMYCOSIS
Not very virulent
(Opportunist)

– Component of Oral Flora
• Periodontal pockets
• Dental plaque
• Tonsilar crypts

• Visceral leishmaniasis: spleen biopsy is a very high sensitive
method of diagnosis
but it is not widely used because of the risk of hemorrhage.
Splenic tissue is rich in amastigotes allowing a rapid and sensitive
diagnosis.

• Visceral leishmaniasis (Kala-azar) is caused by parasites
of the genus Leishmania, subgenus Leishmania, complex donovani
(donovani, infantum, chagasi species).
Viscerotropic strains of L.infantum and L.tropica have been
described.
(BONE MARROW ASPIRATE)

• Visceral leishmaniasis: liver biopsy at higher
magnification with intracellular amastigotes.

ACTINOMYCES

• They are gram +ve rods.
• Anaerobes
• Branching and filamentous in morphology.
Wrongly considered to be fungi because of:
– Morphology
– Disease they cause

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12/7/2015

• A chronic suppurative and granulomatous disease of
the cervico-facial, thoracic or abdominal areas

Incidence:
• Slight male preponderance.(1.5-1 to 3:1)
• Usually 4th to 6th decade.
• Three distinct forms

• (Cervicofacial(50%),pulmonothoracic(30%) and
abdominopelvic forms(20%).

• Form indurated masses with fibrous walls
• Central loculations with pus
– Pus contains "Sulfur Granules"

• Gritty, yellow white
• Average diameter - 2mm
• Composed of mineralized “mycelial” mass

CHRONIC INFECTION

– Form burrowing sinus tracts to skin or mucus
membranes
– This discharges purulent material

Actinomycosis - sulfur granule
.

Causes and risk factors.

Five types have been described;
A.Israeli, A.bovis, A.viscosus, A.naeslun-dii, A.odontolyticus.

• Normally non pathogenic in the nose and throat.

• It causes infection when introduced into the facial tissues by trauma,
dental procedures etc.
• May cause hard abscess and nodule formation; the lumpy jaw.
• Except for bovis all are normal flora of the oral cavity.

Pulmonary Actinomycosis
• Aspiration of organism from the
oropaharynx

• Poor hygiene, dental abscess,
alcohol abuse
– may result in pulmonary
actinomycosis.

• Causes lung cavities ,nodules
and pleural effusions.
• 15% of cases
• Slowly progressive process
involving lung and pleura

– May be mistaken for malignancy

• Chest pain, fever, wt loss and
hemoptysis

The Cervicofacial type;

Fever
• Hard tender lumps with or without open sinuses
mostly in and around the mandibular region
• Sulfur granules in the abscess.
• Wt. loss
• Rarely with cervical lymphadenopathy.
.

Diagnosis:
• Clinical findings.
• Gram stain.
• Culture. (poor growth in culture only in less than 50%
of cases.) Sulphur granules (yellowish myecelial
masses)
• Specimens – open biopsy, aspiration material
• The discharge should mix with sterile saline in a
universal bottle and allow to stand, particles will
separate out.

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12/7/2015

• Causes granulomatous inflammation, like
chronic abscess of the neck, appendix
• Yellow granules in the discharge

• Place between 2 slides
• Crush and gram stain
• Gram positive
branching filaments








Complications:
Osteomyelitis(although not common).
Otitis media.
Meningitis.
Lung infections.
Laryngeal infections

Thanks for Listening

6

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