MODULE 2 UNIT 4 Flashcards
group of protozoa that live in the blood and tissues of their human host and other vertebrates
hemoflagellates
move by means of flagella
hemoflagellates
hemoflagellates is from the family of
Trypanosomatidae
Hemoflagellates infecting man belong to two genera
Leishmania and Trypanosoma
heteroxenous
hemoflagellates
transmission of hemoflagellates
bite of an arthropod vector
four morphologic forms of clinical significance associated with hemoflagellates
amastigote, promastigote, epimastigote, and trypomastigote
amastigote was formerly called
leishmania
promastigote was formerly called
leptomonas
epimastigote was formerly called
crithidia
trypomastigote was formerly called
trypanosoma
It is also known as the L-D (Leishman-Donovan) body.
Amastigote
This stage is adapted to intracellular existence, being found inside macrophages, monocytes, neutrophils, or endothelial cells.
Amastigote
The body is slightly wider than that of the promastigote.
Epimastigote
Volutin granules are found in the cytoplasm.
Trypomastigote
shape and size: ovoidal in shape and, on an average, measures 5 µm long by 3 µm wide
Amastigote
All Leishmania species pass their life cycle in two hosts:
(1) man and other mammalian hosts; (2) insect vector
insect vector host of Leishmania
female sandlfy of the genus Phlebotomus in the Old World, and the genus Lutzomyia in the New World
Leishmaniasis is transmitted by the bite of infected female phlebotomine sandflies. 1) Identify the species; 2) Order of cycle
1) Leishmania; 1
The sandflies inject the infective stage (i.e., promastigotes) from their proboscis during blood meals 1) Identify the species; 2) Order of cycle
1) Leishmania; 2
Promastigotes that reach the puncture wound are phagocytized by macrophages and other types of mononuclear phagocytic cells. 1) Identify the species; 2) Order of cycle
1) Leishmania; 3
Promastigotes transform in these cells into the tissue stage of the parasite (i.e., amastigotes), which multiply by simple division and proceed to infect other mononuclear phagocytic cells 1) Identify the species; 2) Order of cycle
1) Leishmania; 4
Parasite, host, and other factors affect whether the infection becomes symptomatic and whether cutaneous or visceral leishmaniasis results 1) Identify the species; 2) Order of cycle
1) Leishmania; 5
Sandflies become infected by ingesting infected cells during blood meals 1) Identify the species; 2) Order of cycle
1) Leishmania; 6
In sandflies, amastigotes transform into promastigotes, develop in the gut (in the hindgut for leishmanial organisms in the Viannia subgenus; in the midgut for organisms in the Leishmania subgenus), and migrate to the proboscis 1) Identify the species; 2) Order of cycle
1) Leishmania; 7
The Trypanosoma brucei complexes pass their life cycle in two hosts:
(1) man and other mammalian hosts; (2) insect vector
trypanosomiasis vector
tsetse fly of the genus Glossina
During a blood meal on the mammalian host, an infected tsetse fly (genus Glossina) injects metacyclic trypomastigotes into skin tissue. The parasites enter the lymphatic system and pass into the bloodstream 1) Identify the species; 2) Order of cycle
1) Trypanosoma brucei complexes; 1
Inside the host, they transform into bloodstream trypomastigotes , are carried to other sites throughout the body, reach other body fluids (e.g., lymph, spinal fluid), and continue the replication by binary fission 1) Identify the species; 2) Order of cycle
1) Trypanosoma brucei complexes; 2
The entire life cycle of African trypanosomes is represented by extracellular stages. The tsetse fly becomes infected with bloodstream trypomastigotes when taking a blood meal on an infected mammalian host 1) Identify the species; 2) Order of cycle
1) Trypanosoma brucei complexes; 3
In the fly’s midgut, the parasites transform into procyclic trypomastigotes, multiply by binary fission , leave the midgut, and transform into epimastigotes 1) Identify the species; 2) Order of cycle
1) Trypanosoma brucei complexes; 4
The epimastigotes reach the fly’s salivary glands and continue multiplication by binary fission 1) Identify the species; 2) Order of cycle
1) Trypanosoma brucei complexes; 5
The cycle in the fly takes approximately 3 weeks.
African trypanosomiasis
An infected triatomine bug takes a blood meal and releases trypomastigotes in its feces near the site of the bite wound. Trypomastigotes enter the host through the bite wound or intact mucosal membranes, such as the conjunctiva 1) Identify the species; 2) Order of cycle
1) T. cruzi; 1
Inside the host, the trypomastigotes invade cells near the site of inoculation, where they differentiate into intracellular amastigotes
1) T. cruzi; 2
The amastigotes multiply by binary fission and parasitized cells rupture. 1) Identify the species; 2) Order of cycle
1) T. cruzi; 3
Some amastigotes enter further cells and others differentiate through transitional promastigotes and epimastigotes into trypomastigotes, and then are released into the circulation as bloodstream trypomastigotes 1) Identify the species; 2) Order of cycle
1) T. cruzi; 4
Trypomastigotes infect cells from a variety of tissues and transform into intracellular amastigotes in new infection sites where they again multiply by binary fission. The triatomine bug becomes infected by feeding on human or animal blood that contains circulating parasites
1) T. cruzi; 5
The ingested trypomastigotes transform into epimastigotes in the vector’s midgut 1) Identify the species; 2) Order of cycle
1) T. cruzi; 6
. The parasites multiply and differentiate in the midgut and differentiate into infective metacyclic trypomastigotes in the hindgut 1) Identify the species; 2) Order of cycle
1) T. cruzi; 7
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
Leishmania braziliensis complex other names
L. braziliensis, L. panamensis, L, peruviana, and L. guyanensis
L. donovani complex other names
L. donovani, L. infantum, and L. chagasi
Leishmania mexicana complex
L. mexicana, L. amazonensis, and L. venezuelensis
Inhabit the macrophages of the skin, and mucous membranes of the nose and buccal cavity.
Leishmania braziliensis complex; Leishmania mexicana complex
Inhabit the reticuloendothelial cells of the viscera (liver, spleen, bone marrow, intestinal mucosa, and mesenteric venules)
L. donovani complex
Inhabit the endothelial cells of the kidneys, lungs, meninges and CSF
L. donovani complex
The term Old World is used to refer to
Asia, Africa, and Europe
refers to a part of the world that was known to its citizens before it came into contact with the Americans
Old World
New World refers to the Americas and it is inclusive of
North America, South America, and Central America
a general term used to describe diseases caused by genus Leishmania
Leishmaniasis
Old World cutaneous leishmaniasis (CL) agent
Leishmania tropica complex
Leishmania tropica complex 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
Cutaneous leishmaniasis
small red papule; 2 cm or larger in diameter; intense itching
Cutaneous leishmaniasis
crater-like with elevated and indurated margins
Skin ulcer
heals in 2-10 months even without treatment but leaves an ugly, dysfiguring scar
Skin ulcer
cause new world leishmaniasis in South and Central America
Leishmania braziliensis complex and Leishmania mexicana complex
Mucocutaneous leishmaniasis (ML) agent
Leishmania braziliensis complex and Leishmania mexicana complex
Leishmania braziliensis complex and Leishmania mexicana complex other condition names:
- espundia - forest yaws (AKA pian bois (L. guyanensis) - uta
Infection starts off as a reaction at the bite.
Mucocutaneous leishmaniasis (ML)
The skin lesion is similar to cutaneous leishmaniasis but often weeping ulcers.
Mucocutaneous leishmaniasis (ML)
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 (ML)
New World cutaneous leishmaniasis
Leishmania mexicana complex
New World cutaneous leishmaniasis other condition names:
- chiclero ulcer - bay sore
Infection leads to CL that resembles the Old World CL.
New World cutaneous leishmaniasis
chiclero ulcer characterized by ulcerations in pinna is caused by
L. mexicana
Visceral leishmaniasis (VL) agent
Leishmania donovani complex
Old World VL agent
L. donovani and L. infantum
Visceral leishmaniasis (VL) other condition names:
Kala-azar, Dumdum fever, Death fever
- It literally means “black death” 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
- This is the only leishmaniasis that is fatal if not treated
Death fever
American VL [AVL]
New World VL
New World VL agent
L. chagasi
rare papule most likely occurs at the bite site; skin lesions are absent
Visceral leishmaniasis (VL)
Affects internal organs (particularly, spleen, liver, and bone marrow) causing fever, hepatomegaly, jaundice, splenomegaly and lymphadenopathy
Visceral leishmaniasis (VL)
Chronic cases usually lead to death in 1 or 2 years
Visceral leishmaniasis (VL)
acute disease debilitates the patient and becomes lethal in a matter of weeks
Visceral leishmaniasis (VL)
Phlebotomus sandfly
L. tropica; L. aethiopica; L. major
general term used to refer to human diseases caused by hemoflagellates of the genus Trypanosoma
Trypanosomiasis
identified Trypanosoma brucei as the causative agent of the trypanosomal diseases known as nagana and sleeping sickness
David Bruce
T or F: David Bruce is a British pathologist.
F - Scottish
a form of the disease often found in cattle
nagana
T. brucei first described has become known as
Trypanosoma brucei gambiense
was not described until 1910 by Stephens and Fantham
Trypanosoma brucei rhodesiense
causative agent of Chagas’ disease
Trypanosoma cruzi
was later described in 1909 by a young medical student in Brazil named Carlos Chagas
Trypanosoma cruzi
African trypanosomiasis or sleeping sickness
Trypanosoma brucei complexes
causing West African trypanosomiasis
Trypanosoma brucei gambiense
causing East African trypanosomiasis
Trypanosoma brucei rhodesiense
salivarian trypanosomes
T. brucei complexes
undergo anterior station of development
trypomastigotes
They migrate to mouth parts of the vectors, so that infection is transmitted by the their bite (inoculative transmission)
trypomastigotes
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
acute form of African trypanosomiasis (short
course and ends fatally within a year)
T. brucei rhodesiense
African trypanomiasis first sign of infection
African trypanomiasis first sign of infection
painful, red nodule on the skin at the site of bite by 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 African trypanomiasis
It involves nonspecific signs and symptoms such as fever, malaise, headache, generalized weakness, and anorexia and lymphadenopathy.
Stage I African trypanomiasis
refers to the enlargement of the cervical lymph nodes commonly seen in T. b. gambiense infections
Winterbottom’s sign
Other symptoms that may be seen during this stage of the disease include erythematous rash, pruritis, localized edema, and Kerandel’s sign (a delayed sensation to pain).
Stage I African trypanomiasis
characterized by CNS involvement
Stage II African trypanomiasis
Mental retardation, tremors, meningoencephalitis, somnolence (excessive sleepiness), and character changes may develop
Stage II African trypanomiasis
patient slips into a coma and death occurs, resulting from damage to the CNS
Stage II African trypanomiasis
African trypanosomes exhibit unique antigenic variation of their
glycoproteins
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
a single trypanosome may have as many as [?] that help to evade immune response
1,000 or more VSG genes
found in tropical West Africa and Central Africa
T.b. gambiense
species of tsetse flies responsible for the transmission of T.b. gambiense
Glossina palpalis and Glossina tachinoides
riverine species that breed especially in shaded areas along banks of rivers or stream
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
rarely acquired congenitally if the mother is infected during pregnancy
T.b. gambiense
found in East and Central Africa
T. b. rhodesiense
primary species of tsetse flies responsible for the transmitting T.b. rhodesiense
Glossina morsitans, Glossina pallidipes, and Glosssina swynnertoni
Wild game animals, as well as cattle and sheep, are known reservoir hosts of this organism. The disease is actually a zoonosis.
T. b. rhodesiense
It is an occupational hazard for individuals working in game reserves and may also be a threat to visitors of game parks
T. b. rhodesiense
causative agent of American trypanosomiasis which is also known as Chagas’ disease
Trypanosoma cruzi
The Trypanosoma cruzi passes its life cycle in two hosts:
(1) man and other mammalian hosts; (2) insect vector
vector of Trypanosoma cruzi
reduviid bug or triatomine bug
causative agent of American trypanosomiasis which is also known as Chagas’ disease
Trypanosoma cruzi
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 Panstrongylu
reduviid bug or triatomine bug
cone-nosed bug, assassin bug, or kissing bug
reduviid bug or triatomine bug
they tend to bite the host on the face
kissing bug
stercorarian trypanosome
T. cruzi
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)
T. cruzi
Chagas’ disease may be
asymptomatic, chronic, or acute
Chagas’ disease most common initial symptom
chagoma
erythematous nodule produced by the proliferation of the T. cruzi organisms
chagoma
s. This lesion may be present anywhere on the body, but it is most frequently located on the face.
chagoma
Edema as well as a rash around the eyes and face may subsequently occur.
Chagas’ disease
The painful chagoma may last how long before subsiding?
2 to 3 months
Patients who contract T. cruzi through the ocular mucosa develop a characteristic conjunctivitis and unilateral edema of the eyelids, a condition known as
Romaña’s sign.
T. cruzi produces inflammatory response, cellular destruction and fibrosis of muscles and nerves that control tone of hollow organs like heart, esophagus, colon, etc
chronic disease
chronic disease due to T. cruzi results to
cardiac myopathy (cardiomegaly), megaesophagus and megacolon megaesophagus and hepatosplenomegaly
dilatation of esophagus and colon
megaesophagus
The invasion and destruction of various other organs, including those already mentioned, may also contribute to death in chronic patients.
Romaña’s sign.
fever, chills, fatigue, myalgia, and malais
acute Chagas’ disease
An attack of acute infection may result in one of the following scenarios:
(1) recovery; (2) transition to the chronic stage of disease; or (3) death
occurs a few weeks after acute Chagas’ disease attack
death
exists 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
mammalian hosts, dogs and cats are of particular importance as reservoir hosts
triatomine bug
hemoflagellates is from the family of
Trypanosomatidae
Hemoflagellates infecting man belong to two genera
Leishmania and Trypanosoma
heteroxenous
hemoflagellates
group of protozoa that live in the blood and tissues of their human host and other vertebrates
hemoflagellates
Human leishmaniasis is caused by how many Leishmania species that infect mammals?
20 of 30
Mediterranean, parts of the former Soviet Union, Afghanistan, India, Kenya, Middle East (especially in urban areas)
L. tropica
Highlands of Ethiopia, Kenya, perhaps Southern Yemen
L. aethiopica
Former Soviet Union, Iran, Israel, Jordan, parts of Africa, Syria (esp. in rural areas)
L. major
Lutzomyia sandfly
L. braziliensis; L. panamensis; L. peruviana; L. guyanensis;
Mexico to Argentina
L. braziliensis
Panama and Colombia
L. panamensis
Peruvian Andes
L. peruviana
Guiana, Brazil, Venezuela
L. guyanensis
Lutzomyia sandfly
L. mexicana; L. amazonensis; L. venezuelensis
Belize, Guatemala, Yucatan Peninsula
L. mexicana
Amazon River Basin, Brazil
L. amazonensis
Venezuela
L. venezuelensis
Phlebotomus sandfly
L. donovani; L. infantum
Parts of Africa, India, Thailand, Peoples Republic of China, Burma, East Pakistan
L. donovani
Burma, East Pakistan
L. infantum
Lutzomyia sandfly
L. chagasi
Mediterranean Europe, Near East, Africa; also in Hungary; Romania, southern region of former Soviet Union, northern China, southern Siberia
L. chagasi
L. donovani person to person modes of transmission
blood transfusions, sexual contact, congenitally by vertical transmission from mother to fetus, and by accidental inoculation
transmission of hemoflagellates
transmission of hemoflagellates
The most common mode of infection is through bite of sandflies.
Leishmania
occur by direct contact, transmitted from man-to-man or animal-to-man by direct inoculation of amastigotes
Cutaneous and mucocutaneous leishmaniasis
Other less common routes of transmission for T. cruzi
blood transfusions, organ transplantation, transplacental transmission, and foodborne transmission (via food/drink contaminated with the vector and/or its feces)
