by @CONVMEDBOT by @CONVMEDBOT

Haemoflagellates

Dr. Huda R. Sabbar

Al-Anbar university
College of Medicine

◼ All members of the family have similar life cycles.

They all require an insect vector as an intermediate
host.
◼ Parasites metamorphose during development
◼ They live in the blood and tissues of man and other
vertebrate host, and in the gut of the insect vector.
◼ Multiplication in both the vertebrate and
invertebrate host is by binary fission. No sexual
cycle is known
◼ Heamoflagellate has a nucleus,
kinetoplast and a single
flagellum.
◼ The kinetoplast consists of a
deeply staining parabasal body
and the adjacent dot-like
blepharoblast.
◼ The blepharoplast and
parabasal body are connected by
one or more delicate fibrils.
◼ The flagellum arise from the
blepharoplast. The portion of
the flagellum which is inside the
body of the parasite is called as
axonemes or axial filment.

Morphological stages
◼ Amastigotes stage: roundish to oval
, measures 5 by 3 Mm in size.
◼ The amastigote consists of a nucleus
and a kinetoplast.
◼ The large single nucleus is typically
located off-center, some time present
more toward the edge of the
organism. The dote like blepharoplast
gives rise to and is attached to a small
axonemes.
◼ The axonemes extends to the edge of
the organism.
◼ The single parabasal body is located
adjacent to the blepharoplast .
◼ Promastigotes: measure 9
to 15Mm in length.
◼ The large single nucleus is
located in or near the center
of the long and slender
body.
◼ The kinetoplast is located in
the anterior end of the
organism. Asingle free
flagellum extends anteriorly
from the axonemes.

◼ Epimastigotes: measures 9 to
15Mm in length.
◼ The body is slightly wider than
that of the promastigote.
◼ The large single nucleus is
located in the posterior end of the
organism.
◼ The kinetoplast is located anterior
to the nucleus.
◼ An undulating membrane
measuring half the body length
forms into a free flagellum at the
anterior end of the epimastigote.
◼ Trypomastigotes: measures 12-
35Mm long by 2-4 Mm wide.

◼ assume the shape of the letters C

or U in stained blood film.

◼ The long, slender organism is

characterized by a posteriorly
located kinetoploast from which
emerges a full body length
undulating membrane. The single,
large nucleus is located anterior to
the kinetoplast.
◼ An anterior free flagellum may or
may not be present.

Clinical classification of Leishmaniasis

◼ Visceral leishmaniasis:(VL, kala azar) is the most

severe form and if untreated has a mortality rate
approaching 100%. This form is
◼ characterized by fever, weight loss, enlargement of
the spleen and liver and anaemia. Caused exclusively
by species of the L. donovani complex (L. donovani,
L. infantum , L. chagasi)
◼ Mucocutaneous leishmaniasis:(MCL) produces
lesions which can lead to extensive and disfiguring
destruction of mucous membranes
◼ of the nose, mouth and throat cavities.
◼ Cutaneous leishmaniasis (CL) manifests with
sores or ulcers on:
◼ exposed parts of the body such as arms, legs
and face which may heal spontaneously, but
the diffuse form of CL does not heal and may
relapse after treatment.

Types of Leishmania
◼ Leishmania tropica: causing oriental sore, the infection is
limited to local lesions of the skin and subcutaneous tissues.

◼ Leishmania donavani: causing kala-azar, the infection is

generalized and the parasites are distributed in the internal
organs,therefore the disease is called visceral leishmaniasis.

◼ Leishmania braziliensis: causing Espundia, the infection is

limited to local lesion of the skin and nasopharyngeal mucous
membrane.
◼ Leishmania infantum: is found along the whole
Mediterranean area , human infections are confined almost
entirely to children, humans are considered to be an accidental
host, with natural infections occurring in dogs.
 Life cycle
◼ The sand fly vector becomes infected when feeding on the
blood of an infected individual or an animal reservoir host.
◼ The leishmania parasites live in the macrophages as round,
non-motile amastigotes (3-7 micrometers in diameter).
◼ The macrophages are ingested by the fly during the blood-
meal and the amastigotes are released into the stomach of
insect.
◼ immediately the amastigotes transform in to the motile,
elongated (10-20 micrometers), flagellate promastigote form.

◼ The promastigotes then migrate to the alimentary tract of the

fly, where they live extracellularly and multiply by binary
fission.
◼ Four to five days after feeding the promastigotes move
forward to the oesophagus and the salivary glands of the
insect.
◼ When the sandlfy next feeds on a mammalian host, it's
proboscis pierces the skin and saliva containing anti-coagulant
is injected into the wound to prevent the blood from clotting,
◼ the leishmania promastigotes are transferred to the host along
with the saliva.
◼ Once in the host the promastigotes are taken up by the
macrophages where they rapidly revert to the amastigote form
◼ multiplication inside the
macrophages, leading to the lysis
of the macrophages.
◼ The released amastigotes are
taken up by additional
macrophages and so the cycle
continues.
◼ Ultimately all the organs
containing macrophages and
phagocytes are infected,
especially the spleen, liver and
bone marrow and less often in
other locations such as the skin,
intestinal mucosa and mesenteric
lymph nodes.
◼ Small number of LD bodies can
be found in blood

Insect vector
◼ The vector of the leishmania parasite is the blood-sucking
female of the genus Phlebotomus in the old world and
Lutzomyia in the new world.
◼ The insects are 2-3 mm long and are found through-out
the tropical and temperate parts of the world.
◼ The sandfly larvae require organic matter, heat and
humidity for development .
◼ found in house-hold rubbish, bark of old trees, burrows
of old trees and in cracks in house walls.
◼ The sandflies usually feed at night while the host is
asleep.
 Visceral Leishmaniasis
◼ visceral leishmaniasis including Dum-dum fever, Sikari
disease, Burdwan fever, Shahib's disease and tropical
splenomegaly.
◼ The most commonly used term is Kala azar, which in Hindi
means black sickness or black fever.
◼ Visceral leishmaniasis is caused by the parasites Leishmania
donovani donovani, Leishmania donovani infantum in the old
world and by Leishmania donovani chagasi in the new world.
◼ Although people of all ages are susceptible in the old world,
children below the age of 15 are more commonly affected with
L.d infantum
◼ Symptom :undulating fever often with two or even
three peaks in 24 hours and drenching sweats which
can easily be misdiagnosed as malaria, Chills, rigors,
weight loss, fatigue, poor appetite, cough, burning
feet, insomnia, abdominal pain, joint pain, anorexia,
epistaxis and diarrhoea.
◼ Clinical sings include splenomegaly, hepatomegaly
and lymphadenopathy
◼ The incubation period is highly variable, the disease
can appear anything between ten days to over one
year.
◼ the skin becomes dry, rough and darkly pigmented,
the hair becomes thin and brittle.

◼ Visceral leishmaniasis can be complicated by serious

secondary bacterial infections such as pneumonia, dysentery
and pulmonary tuberculosis, which often contribute to the high
fatality rate of VL patient
◼ Post kala-azar dermal leishmaniasis (PKDL : recurrence of
Kala-azar that may appear on the skin of affected individuals
up to 20 years after being partially treated, untreated or even in
those considered adequately treated.
◼ .They manifest as hypo-pigmented macules, papules, nodules,
or facial erythema (butterfly patches) .

◼ it is commonly associated with L. donovani.

◼ Post-kaka-azar

◼ Profile view of a
teenage boy suffering
from visceral
leishmaniasis. The boy
exhibits splenomegaly,
distended abdomen
and severe muscle
wasting.
 Daignosis
◼ Clinical :such as splenomagaly, hepatomegally and high
undulating fever
◼ Parasitological: Spleen and liver biopsy; Part of the splenic
aspirate can be used to make smears for direst microscopic
examination and cultured on Novy- MacNeal- Nicolle (NNN)
or Schneider's insect medium supplemented 10% v/v foetal
calf serum.
◼ Liver biopsy material is less likely to demonstrate
parasites on direct examination or on culture.
◼ histological examination will show amasatigotes in
Kupffer cells in the portal system.

◼ Marrow and lymph gland puncture Marrow obtained from sternal or

iliac crest puncture is a much safer but a painful method.
◼ It is less likely to demonstrate parasites in direct stained films
◼ on culture it can give positive results in up to 80% of the cases.
◼ Blood in anticoagulant is centrifuged at 2000g for 10 min and the cells
from the buffy coat removed and used to prepare smears and inoculate
cultures.
◼ Serological methods
◼ Indirect fluorescent antibody test (IFAT)
◼ Direct agglutination test
◼ Enzyme linked immunosorbent assay (ELISA)
◼ Complement fixation test
◼ PCR technique, this method based on the amilification of
the leishmania DNA by using specific primer which
depend on the sequence of nitrogen bases in the leishmania
genome.
 Cutaneous leishmaniasis
L. tropica.(old world)
◼ L. tropica minor: cause urban cutaneous leishmaniasis, dry
type , reservoir host is dog.
◼ L. tropica major: cause rural cutaneous leishmaniasis, wet
type, reservoir host is rodent, produces an acute infection with
a duration of 3 to 6 months.
◼ The lesions occur primarily on the lower limbs, they are moist
and tend to ulcerate very early; there may be secondary or
satellite lesions.
◼ L. aethiopica produce a similar chronic disease,seen in the
highland of Ethiopia
◼ New world C.L. …L. mexicana and L. braziliensis
◼ The incubation period lasts from a few days to several months.

◼ The first symptom of infection is a small, red papule at the

site of the bite, which may itch intensely and grows to 2 cm or
more in diameter.
◼ In L. major infections, the papule is covered with a serous
exudates and ulcerates early;
◼ papules are dry and ulcerate only after several months in L.
tropica and L. aethiopica infections..
◼ This papule may disappear in few weeks,
◼ usually it develops a thin crust that hides a spreading ulcer
underneath.
◼ Two or more ulcers may coalesce to form a large sore .
◼ In uncomplicated cases the ulcer will heal within two months
to a year, leaving a depressed , unpigmented scar.

◼ L. tropica is found in more densely populated areas.

◼ Its lesion is dry, persists for months before ulcerating , and
has numeratous amastigotes within it.
◼ L. major is found in sparsely inhabited regions. Its papule
ulcerates quickly, is of short duration, and contain few
amastigotes.
◼ Scraping from the side
or edge of the ulcer
smeared on a slid and
stained with Wrights or
Giemsa stain .
◼ will show the parasites
in endothelial cells and
monocytes.
◼ No in blood
◼ Leishmanin or Montenegro
test , a skin test and is used
to measure delayed
hypersensitivity.
◼ 0.1ml of antigen suspension
of washed promastigotes in
0.5 percent phenol saline in
a strength of 10 percent is
injected intradermally
◼ positive result is indicated
by an induration of 5mm or
more in 48-72 hours
◼ Treatment
◼ By sodium stibogluconate(less toxic than the
earlier pentavalent antimonials,Pentostam)
◼ is the most effective compound available for
treatment of all cutaneous leishmaniasis except
the Ethiopian form of diffuse cutaneous
leishnaniasis is more effected by pentavalent
antimonials.

◼ Mucocutaneous leishmaniasis
◼ L. brazilinensis produces a disease in humans known as
espundia, uta, or mucocutaneous leishmaniasis.
Morphologically, L. braziliensis cannot be differentiated from
L. tropica, L. mexicana, or L. donovani.
◼ Life cycle is similar to other type, except, the vector is
Lutzomyia.
◼ In some times the lesions appear as flat, ulcerated plaques that
remain open and oozing. The disease is called pian bois in
Venezuela and Paraguay
◼ L. braziliensis, the parasites have a tendency to metastasize , or
spread directly from the primery lesion to mucocutaneous
zones.
◼ The secondary lesion often involves the nasal system and
buccal mucosa,causing degeneration of the cartilages and soft
tissues
◼ Necrosis and secondary bacterial infection are common.
Espudia and uta are the names applied to these condition
◼ The ulceration may involve the lips, palate, and pharynx,
leading to great deformity.
◼ Invasion of the infection into the larynx and trachea destroys
the voice.
◼ The condation may last for many years, and death may result
from secondary infection or respiratory complications.
 Diagnosis and treatment
◼ Diagnosis is established by finding L-D
bodies in affected tissues
◼ Treatment is similar to kala-azar and
tropical sore, antimonial compounds
applied on the lesions or injected
intravenously or intramuscularly .
◼ Secondary bacterial infections should be
treated with antibiotics.

◼ Leishmania mexicana .. This parasite of New world is found in northen

central America, Mexico,Texas.

◼ The cutaneous form of disease has been called chiclero ulcer because it is
so common in chicleros forest-dwelling people .
◼
◼ Cutaneous leishmaniasis due to L. mexicana usually heals spontaneously in
a few months except when the lesions are in the ear. Ear cartilage is poorly
vascularized so immune responses are weak

◼ Leishmaniasis recidivans .. : a partially healing leishmanial lesion

caused by Leishmania tropica and characterized by an extreme form of
cellular immune response, intense granuloma production,
fibrinoid necrosis without caseation, and frequent development of
satellite lesions that continue the production of granulomatous tissue and
scarring without healing, sometimes over a period of many years;
organisms are difficult to demonstrate but can be cultured.

◼
 Prevention
◼ there is some evidence that people who have had cutaneous infections have
heightened resistance to future visceral or cutaneous infections so some
researchers are looking into the possibility of infection with an attenuated
strain in the epidermis to cause a mild cutaneous infection.

◼ the only effective preventative measure is to prevent sand fly

bites either by killing them with pesticides or by using
insect.repellents

Epidemiology
◼ The infection produced by L. tropica is generally transmitted from one
human to another, the other forms of cutaneous leishmaniasis are
principally zoonses
◼ contact infection is possible, and vaccination is practiced in certain areas by
inoculating serum from naturally acquired lesions into an inconspicuous
location on the body of a nonimmune person.Various clinical forms of
visceral leishmaniasis are characteristic of of different localities.
◼ In the urban forms, transmission is primarily from human to
human.
◼ A rural form of transmission , seen in other areas , is primarly
a zoonoses.