[DISCUSSION] MODULE 2 UNIT 4 Flashcards
group of protozoa that live in the blood and tissues of their human host and other vertebrates, and that move by means of flagella
Hemoflagellates
Under family Trypanosomatidae
Hemoflagellates
Hemoflagellates infecting man belong to two genera:
Leishmania and Trypanosoma
Transmission via arthropod vector bite
Hemoflagellates
DEVELOPMENTAL FORMS
Inhabit the macrophages of the skin and nearby lymph nodes
Leishmania tropica complex
Leishmania tropica complex other names
L. tropica, L. aethiopica, and L. major
Inhabit the macrophages of the skin, and mucous membranes of the nose and buccal cavity
Leishmania mexicana complex
Leishmania braziliensis complex
L. braziliensis, L. panamensis, L, peruviana, and L. guyanensis
Leishmania mexicana complex
L. mexicana, L. amazonensis, and L. venezuelensis
Inhabit the reticuloendothelial cells of the viscera (liver, spleen, bone marrow, intestinal mucosa, and mesenteric venules)
L. donovani complex
L. donovani complex
L. donovani, L. infantum, and L. chagasi
- also in the endothelial cells of the kidneys, lungs, meninges and CSF
L. donovani complex
Old world cutaneous leishmaniasis (CL)
Leishmaniasis tropica complex
Leishmania braziliensis complex
Mucocutaneous leishmaniasis (ML)
Visceral leishmaniasis (VL)
Leishmania donovani complex
Leishmania tropica complex
Disease: Old World cutaneous leishmaniasis (CL)
other condition names:
-oriental sores-tropical sore-Aleppo button-Jericho boils-Delhi boils-Baghdad boils
causes cellular infiltration, necrosis and ulceration, and granuloma formation.
Sandfly bite on the skin
-characterized by one or more ulcers containing pus that generally self-heal
Leishmaniasis tropica complex
Disease: Old World cutaneous leishmaniasis (CL)
-infected patients initially develop a small red papule, located at the bite site, which is typically 2 cm or larger in diameter and may cause intense itching
Leishmaniasis tropica complex
Disease: Old World cutaneous leishmaniasis (CL)
crater-like with elevated and indurated margins
Skin ulcer
ulcer heals in 2-10 months even without treatment but leaves an ugly, disfiguring scar
Leishmaniasis tropica complex
Disease: Old World cutaneous leishmaniasis (CL)
Leishmania braziliensis complex
Disease: Mucocutaneous leishmaniasis
other condition names:
- Espundia- forest yaws AKA pian bois (L. guyanensis)- uta
Infection starts off as a reaction at the bite.
Mucocutaneous leishmaniasis
The skin lesion is similar to cutaneous leishmaniasis but often weeping ulcers.
Mucocutaneous leishmaniasis
It can go by metastasis into the mucous membrane of the nose, ears, pharynx and/or larynx causing extensive dysfiguring lesion and can become fatal.
Mucocutaneous leishmaniasis
New World cutaneous leishmaniasis other condition names:
-chiclero ulcer-bay sore-uta
Infection leads to CL that resembles the Old World CL.
New World cutaneous leishmaniasis
However a specific lesion of caused by L. mexicana is (?) which is characterized by ulcerations in pinna.
chiclero ulcer
Visceral leishmaniasis (VL) caused by:
L. donovani and L. infantum
Visceral leishmaniasis (VL)
other condition names:
-Kala-azar
-Dumdum fever
-Death fever
literally means “black death“
-Kala-azar
in India, referring to the characteristic darkening of the skin of the forehead and temple
-Kala-azar
the parasite was discovered by Dr. William Leishman from the spleen smear of a soldier who died of the disease in Dumdum, Calcutta, India
-Dumdum fever
complication of visceral leishmaniasis (VL)
Post-kala-azar dermal leishmaniasis (PKDL)
characterised by a macular, maculopapular, and nodular rash in a patient who has recovered from VL and who is otherwise well
Post-kala-azar dermal leishmaniasis (PKDL)
The rash usually starts around the mouth from where it spreads to other parts of the body depending on severity
Visceral leishmaniasis (VL)
Visceral leishmaniasis (VL) is mainly seen in Sudan and India where it follows treated VL in (?) of cases, respectively
50% and 5–10%
American VL [AVL]
New World VL
New World VLis caused by
L. chagasi
Other than a rare papule, which most likely occurs at the bite site, skin lesions are absent.
New World VL
It affects internal organs (particularly, spleen, liver, and bone marrow) causing fever, hepatomegaly, jaundice, splenomegaly and lymphadenopathy.
New World VL
The most common mode of infection is through bite of sandflies
Leishmania
It is important to note that L. donovani is capable of being transmitted person to person via (?), congenitally by (?) from mother to fetus, and by (?) in the laboratory
blood transfusions
vertical transmission
accidental inoculation
An alternative sexual transmission route is well documented in dogs but evidence is lacking in humans
L. donovani
Cutaneous and mucocutaneous leishmaniasis may also sometimes occur by direct contact, transmitted from (?) by direct inoculation of amastigotes
man-to-man or animal-to-man
- Previously referred to as Trypanosoma brucei
Trypanosoma brucei gambiense
- identified as the causative agent of nagana (a form of the disease often found in cattle) and sleeping sickness.
Trypanosoma brucei gambiense
Trypanosoma brucei gambiense
In 1895 by (?), a Scottish pathologist
David Bruce
West African trypanosomiasis
Trypanosoma brucei gambiense
- was not described until 1910 by Stephens and Fantham
Trypanosoma brucei rhodesiense
- East African trypanosomiasis
Trypanosoma brucei rhodesiense
- the causative agent of Chagas’ disease
Trypanosoma cruzi
- described in 1909 by a young medical student in Brazil named Carlos Chagas
Trypanosoma cruzi
-causes the chronic form of African trypanosomiasis
T. brucei gambiense
-mild, long course that ends fatally with central nervous system (CNS) involvement after several years’ duration.
T. brucei gambiense
-causes the acute form of African trypanosomiasis
T. b. rhodesiense
-that has a short course and ends fatally within a year
T. b. rhodesiense
The Trypanosoma brucei complexes pass their life cycle in two hosts:
(1)man and other mammalian hosts
(2)insect vector, tsetse fly of the genus Glossina.
salivarian trypanosome
T. brucei complexes
They migrate to mouth parts of the vectors, so that infection is transmitted by the their bite (inoculative transmission).
T. brucei complexes
-The first sign of infection is the development
Trypanosomal chancre
-painful, red nodule on the skin at the bite of the tsetse fly
Trypanosomal chancre
-The lesion will resolve spontaneously within 1 to 2 weeks
Trypanosomal chancre
This is systemic trypanosomiasis when trypomastigotes are in the blood and lymph nodes without central nervous system involvement.
Stage I Trypanosomal chancre
It involves nonspecific signs and symptoms such as fever, malaise, headache, generalized weakness, and anorexia and lymphadenopathy.
enlargement of the cervical lymph nodes commonly seen in T. b. gambiense infections.
Winterbottom’s sign
This is characterized by CNS involvement.
Stage II Trypanosomal chancre
Mental retardation, tremors, meningoencephalitis, somnolence (excessive sleepiness), and character changes may develop.
Stage II Trypanosomal chancre
The patient slips into a coma and death occurs, resulting from damage to the CNS.
Stage II Trypanosomal chancre
exhibit unique antigenic variation of their glycoproteins
African trypanosomes
There is a cyclical fluctuation in the trypanosomes in the blood of infected vertebrates after every
7- 10 days
Each successive wave represents a variant antigenic type (VAT) of trypomastigote possessing
variant-specific surface antigens (VSSAs) or variant surface glycoprotein (VSG) coat antigen
found in tropical West Africa, and Central Africa
T.b. gambiense
T.b. gambiense Vectors
Glossina palpalis and Glossina tachinoides
riverine species that breed especially in shaded areas along banks of rivers or streams
Glossina palpalis and Glossina tachinoides
Transmission can occur when people frequent these areas to swim or do they laundry.
T.b. gambiense
There are no known animal reservoir hosts.
T.b. gambiense
may be acquired congenitally if the mother is infected during pregnancy
T. b. gambiense
attracted to the blue color and land on the netting
tsetse flies
Posted along rivers in Uganda; The net is covered in insecticide which attaches to the flies and kills them within three minutes
Blue targets
found in East and Central Africa
T.b. rhodisiense
T.b. rhodisiense Vectors:
Glossina morsitans, Glossina pallidipes and Glossina swynnertoni
Attack wild game animals
Glossina morsitans, Glossina pallidipes and Glossina swynnertoni
known reservoir hosts of T.b. rhodisiense
Wild game animals, as well as cattle and sheep
It is an occupational hazard for individuals working in (?) and may also be a threat to (?)
game reserves; visitors of game parks
Causative agent of American trypanosomiasis
Trypanosoma cruzi
Chagas’ disease
American trypanosomiasis
The Trypanosoma cruzi passes its life cycle in two hosts:
(1)man and other mammalian hosts
(2)insect vector, bug in the family Reduviidae, subfamily Triatominae: Commonly belong to the genera of Triatoma, Rhodnius, and Panstrongylus.
They are commonly referred to as reduviid bug or triatomine bug.
Trypanosoma cruzi
They are also called cone-nosed bug, assassin bug, or kissing bug (because they tend to bite the host on the face).
Trypanosoma cruzi
stercorarian trypanosome
T. cruzi
In the vector, they undergo posterior station of development.
T. cruzi
migrate to hindgut and are passed in feces
trypomastigotes
Infection is acquired by rubbing the feces of the vector into the wound caused by its bite or into the mucous membrane conjunctiva (contaminative transmission).
Trypanosoma cruzi
-an erythematous nodule at the site of infection produced by the proliferation of the T. cruzi organisms
Chagoma
-frequently located on the face
Chagoma
-may last 2 to 3 months before subsiding.
Chagoma
characteristic conjunctivitis and unilateral edema of the eyelids
Romaña’s sign
In chronic disease, it produces inflammatory response, cellular destruction and fibrosis of muscles and nerves that control tone of hollow organs like heart, esophagus, colon, etc.
T. cruzi
chronic disease, T. cruzi, results to
cardiac myopathy (cardiomegaly), megaesophagus and megacolon megaesophagus (dilatation of esophagus and colon) and hepatosplenomegaly
only in the American continent (western hemisphere) and is limited to South and Central America only
T. cruzi
nests in human homes that are open in design
triatomine bug
Although there are a number of known mammalian hosts, dogs and cats are of particular importance as reservoir hosts.
T. cruzi
Other less common routes of transmission include blood transfusions, organ transplantation, transplacental transmission, and foodborne transmission (via food/drink contaminated with the vector and/or its feces). 3
T. cruzi
