5. Giarida lamblis 梨形鞭毛蟲 (Syn. G. duodenalis)
Common infection in both tropic and sub-tropic area
Small intestine infection
Cystic infection, 10 cysts may
produce infection
Infection via contaminated
food and water
Excystation occurs in upper
small intestine
8. Giarida lamblis
Life cycle
Trophozoite: symmetrical in shape (badminton racket)
2 oval nuclei;
4 pairs of flagella; moving as “falling leaf”
binding to tissue
by striated disc (ventral surface) mechanical binding
by host proteases activate the lectin of Giardia to
promote attachment to enterocytes (腸細胞)
multiple by binary fission
9. Giarida lamblis
Life cycle
Cyst: oval to ellipsoid in shape (11-14 μm)
4 small oval nuclei
distinct wall; shrunk cytoplasm
produce a space under cyst wall
10.
11.
12. Giarida lamblis
Clinical aspects
Wide range of gastrointestinal symptoms (especial in children)
Vomiting 嘔吐
Flatulence 腸胃脹氣; Diarrhoea 痢疾,下痢
Malabsorption syndrome 吸收障礙
Cholecystitis 膽囊炎
13. Giarida lamblis
Clinical aspects
Histological aspects : mechanical & biochemical
Shortening of villi
Cellular infiltration of lamnia propria黏膜固有層 of
mucous membrane functional impairment of enterocytes
Abdominal cramps腹部絞痛 痙攣
Induce motility disturbance
14. Giarida lamblis
Diagnosis
Stool examination
for trophozoites or cysts diagnosis
may concentrated by zinc sulphate flotation硫酸鋅浮漂法
Duodenal aspiration
“Enterotest” capsule腸內測試膠囊
a gelatin capsule containing a coiled thread
for duodenal contents diagnosis
16. Giarida lamblis
Prevention and control
Food hygiene
Fly control
Sewage disposal
Proper water supply
Identification and treatment of carriers
Chlorination of water can not kill the cysts
Iodination of water can kill the cysts
(13 ml saturated solution of iodine per liter of water
17. Trichomonas spp 滴蟲
Life cycle
Trophozoite: ovoid or pyriform
gliding motion
1 or 2 oval nuclei
4 flagella on anterior end
1 flagellum turns back and attach on undulating membrane
axostyle軸柱 projects out of body
for attach to host tissues and cause irritation
divide by binary fission
No cystic stage
21. Trichomonas vaginalis
Life cycle
Trophozoite: ovoid or pyriform
gliding motion
single oval nuclei
4 flagella on anterior end
1 flagellum turns back and attach on undulating membrane
axostyle projects out of body
for attach to host tissues and cause irritation
ingests food particles by cytostome
Divide by binary fission
22. Trichomonas vaginalis
Clinical aspects
Vaginitis (陰道炎)
resulting in a frothy and creamy white discharge
Inflame of vulva and cervix
Asymptomatic in males
but some urethritis(尿道炎) or (prostatitis)前列腺炎
24. Trichomonas vaginalis
Treatment
infected female and her male consort
Drug treatment
Nitroimidazoles
Metronidazole; 200 mg thrice daily orally for 1 week
2 g for single doses
Tinidazole ; 2 g thrice daily orally
Ornidazole;
26. Haemoflagellates 血液性鞭毛蟲
Leishmania spp 利什曼原蟲
L. donovani complex; L. major
L. tropica; L. aethiopica
L. mexicana complex
L. braziliensis complex; L. peruviana
Trypanosoma spp 錐蟲
T. rhodesiense; T. gambiense
T. cruzi; T. rangeli
27. Leishmania spp infecting man
Geographical distribution
Visceral leishmaniasis (VL)內臟利什曼原蟲症
India, Bangladesh, scattered areas in the Middle East
Mediterranean region, parts of East Africa,
South and Central America
Cutaneous leishmaniasis (CL)皮下利什曼原蟲症
N. India, Pakistan, Middle East, Southern Europe
Northern Africa all Mediterranean Coast,
parts of East and West Africa, South and Central America
Muco-cutaneous leishmaniasis (MCL)黏膜利什曼原蟲症
South and Central America
28. Leishmania spp infecting man
Taxonomic position is often confusing
monoclonal antibody typing
DNA probe hybidization
RFLP
karyotyping
L. donovani complex;
L. major
L. tropica; 熱帶利什曼原蟲
L. aethiopica
L. mexicana complex
L. braziliensis complex;
L. peruviana
29. General Classification of Important Leishmaniasis
in Relation to Clinical Manifestation
Clinical
Manifestation
Species Involved
Old world New world
VL L. donovani
complex
L. donovani
complex
MCL Rarely occurs L. braziliensis
complex
CL L. tropica L. braziliensis
complex
L. major L. mexicana
complex
30. Leishmania spp
Morphology 4 types fig. 30
Trypomastigote 錐鞭毛體
kinetoplast is at posterior end, locomotory flagellum,
long undulating membrane(supported by microtubules),
Epimastigote側鞭毛體
kinetoplast is anterior to the nucleus, short U membrane
Promastigote前鞭毛體
kinetoplast is at anterior end, no U membrane
Amastigote無鞭毛體(“Leishman-Donovan” body)
ovoid, 2-3 μm, no flagellum
binary fission, starts by division of the kinetoplast,
following nucleus division,
ending the outer membrane splits
35. Host cell infection by promastigotes
flagellar attachment or aflagellar poles
phagocytosis by host cells
Macrophages
Phagocytic cells
Become amastigotes inside a parasitophorou vacuole
Binary fission for multiplication
1.eliciting a small phagocytic oxidative response
2.possessing membrane-associated acid phosphotase
3. Possessing more catalase & glutathione peroxidase than
promastigotes
Toxoplasma gondii : preventing phagosome-lysosome fusion
36.
37.
38.
39. Leishmania spp infecting man
Clinical aspects
Difference in virulence of various parasite species
Difference in susceptible of various host
Muco-cutaneous leishmaniasis (MCL)黏膜利什曼原蟲症
Starts as a pustular swelling in mouth or on nostrils
Lesion become ulcerative after many months
Then extend into the naso-pharyngeal mucous membrane
2nd infection is very common with destruction of the nasal
cartilage and the facial bone
41. Leishmania spp
Visceral leishmaniasis (VL)內臟利什曼原蟲症: Kala-azar黑熱病
Incubation period is 4 to 10 months
Early symptoms: low grade fever with malaise and sweating
Later stages: fever become intermittent
hyperplasia of lymphoid-macrophage system
liver and spleen become grossly enlarged
no inflammatory changes
lymphadenitis is common in Chinese form but not Indian form
post Kala-azar dermal lieshmaniasis (PKDL) after 1 –2 years
hypopigmented areas; nodular as lepromatous leprosy
skin biopsy shows many parasites
PKDL is of epidemiological significance
vector transmission easily
42. Leishmania spp
Cutaneous leishmaniasis (CL)皮下利什曼原蟲症
Starts as a painless papule(丘疹) on exposed parts of body
generally on the face
Circular or oval ulcer produce
Lesion ulcerates after few months
dry type lesion: ulcer remains dry and heals readily
wet type lesion: ulcer may spread with inflammatory
zone around it, and heal slowly
Diffuse cutaneous leishmaniasis (DCL)
occur in parts of Africa
Nodules and thickening of the skin without any ulceration
Leishmaniasis recidivans (LR): chronic infection with
very few parasites, not heal spontaneously
45. Leishmania spp
Prevention and control
Vector control
Residual insecticides spread for control sandflies
High susceptible to insecticide of sandflies
Reservoir animal control
Vaccination with promastigotes in cutaneous leishmaniasis
U.S.S.R and Israel
Personal protection
long sleeves and trousers; insect repellents;
fine mesh nets impregnated with insecticides
46. Trypanosoma spp infecting man
Sleeping sickness非洲睡眠病 ： Africa
Trypanosoma rhodesiense羅德西亞錐蟲
Trypanosoma gambiense甘比亞錐蟲
Chagas’ disease ： America
Trypanosoma cruzi枯西式錐蟲
Non pathogenic ： Central and South Africa
Trypanosoma rangeli
47. African trypanosomes (sleeping sickness)
Pathogens：Trypanosoma rhodesiense 羅德西亞錐蟲
Trypanosoma gambiense 甘比亞錐蟲
(morphologically indistinguishable)
Vector：biting flies; tsetse fly 采采蠅; Glossina
parasite undergoes a complex development in fly
Host：host in human blood with binary fission
movement in the direction of flagellum
pleomorphic; slender; intermediate; stumpy
nucleus, kinetoplast, undulating membrane, flagellum
can be recognised with stain
48.
49.
50.
51. Geographical distribution
Trypanosoma rhodesiense 羅德西亞錐蟲
East Africa
Rhodesian form sleeping sickness; zoonosis
Trypanosoma gambiense 甘比亞錐蟲
Western and Central Africa
Gambian form sleeping sickness: human
52. Life cycle Page 46 fig. 36
Host：divided by binary fission
slender; intermediate; stumpy
Vector：stumpy form initiated in midgut surrounded with PM
(peritrophic membrane )
Change to elongated form (longer)
Migrate to the space between PM and midgut, become
a shorter elongated form
Penetrate PM and forward movement to proboscis
Turn back migrate to salivary gland, become a epimastigotes
further develop to metacyclic form
Infect host via biting injection with saliva
may be penetrate into haemocoel via midgut
53. Antigenic variation抗原變異作用
Fascination mechanism for escape host immunity
Avoid host immune response
Protecting the parasites from antibodies
Change and replacing outer variant surface glycoprotein (VSG)
Weekly or 10-day cycle
Antigenically different
Serotype; heterotype
Limitation : unlimitation ?
54. Clinical Aspects
Primary reaction 初始感染反應
Small sub-cutaneous nodule 皮下瘤結
occurs at the site of inoculation of Tyrpanosoma
become a larger nodule, 25 to 100 mm in diameter
persist about 2-3 weeks
55. Clinical Aspects
Systemic manifestation 系統性病變
Fever with headache
Winterbottom’s sign: T. gambiense
lymph gland become enlarged (cervical & suboccipital)
Fever becomes intermittent in later stages
CNS involvement
daytime sleeping; psychological changes; tremors震顫;
convulsions全身痙欒; coma昏迷
Death generally occurs from intercurrent infection併發感染
56. Clinical Aspects
T. rhodesiense infection
fast with CNS involvement occurring within a few months
Pathology of CNS
leptomeningitis軟腦膜炎
cellular infiltration組織浸潤 : mononuclear cells
perivascular cuffing圍管現象 : around the blood vessels
plasma cells and lymphocytes
57. Diagnosis
•Lymph gland puncture: T. gambiense
•Blood diagnosis: T. rhodesiense
•DEAE column separation: parasites concentration form blood
•Immuno-assay: CFT; complement fixation test
• FAT; fluorescence antibody test
•IgM level rise: blood & CNS (trypanosomiasis’ pathognomonic)
•Rats inoculation with T. rhodesiense : heavy parasitaemia
•Card agglutination trypanosomasis test (CATT)
•
58. Differences Between T. gambiense and T. rhodesiense
T. gambiense T. rhodesiense
Virulence
Less virulent to
humans and
laboratory animals
More virulent to
humans and laboratory
animals
Reservoir Mainly humans Mainly animals
Vector
Mainly Glossina
palpalis
Mainly Gglossina
morsitans
Geographical
distribution
Mainly West Africa Mainly East Africa
59. Treatment
Depending on CNS condition
Early stage:
suramin (germanin)
0.2g intravenously injection for side reaction test
0.8g apply on day 2
1 g every 4th day until a total 10g is given
•Blood-brain barrier effect; BBB
•Enphrotoxic (kidney failure patient avoid use)
60. Treatment
Late stage:
melarsoprol with dimercaprol (reduce toxicity)
cells and protein levels higher than 40mg/100ml
20mg/kg; intravenously injection;3 course treatment
each course 3 days; separated by 7 days rest
Side effect: stop to rescue
Encephalopathy : arsenical encephalopathy 砷腦病變
reactive encephlopathy 反應性腦病變
Eflornithine : early Gamabian trypanosomiasis
61. Prevention and control
Gambian form sleeping sickness: human
Riverine tsetse : for collecting water or for washing people
Rhodesian form sleeping sickness; zoonosis
Reservoir host reducing
Wild game destruction
Vector control : tsetse fly elimination
color attract: blue & black
residues application of insecticide
62. American trypanosomes (Chagas’ disease)
Geographical distribution
South America
Central America
Vectors
Reduviid bugs: Triatoma,
Panstrongylus. Rhodnius
Reservoir animal
Armadillos犰狳 , opossums小袋鼠, cats, dogs, pigs
63. Life cycle of Trypanosoma cruzi
Metacyclic form is infectious form
Pass through the faeces of infected vector
Parasites via skin damaged by the bite of assassin bug
via the contamination mucous membranes
Penetrate into tissue cells from blood stream
mesenchymal origin間質細胞
cardiac muscle mainly 心肌細胞
Change into amastigote , epimastigote, trypomastigote
Replication only occur in amastigote
Trypomastigote emerge form muscle cells and enter blood stream
Re-invasion : cardiac muscle cells
circulate without division
64.
65.
66. Life cycle of Trypanosoma cruzi
Vector
Trypomastigote picked up by insect
Change to epimastigotes
Becoming metacyclic form after 8-10 days in the hindgut of vector
T. cruzi also transmissable by the congenital route
or blood transfusion
Large kinetoplast and curved appearance
distinguish with T. gambiense & T. rhodesiense
Congenitial route or blood transfusion infection
67.
68. Life cycle of Trypanosoma cruzi
T. Cruzi survive in the cytoplasm of macrophages
not in the parasitophorous vascuole of macrophages
(Leishmania & Toxoplasma)
69. Clinical aspects
Chagoma as primary lesion:
on the face near eyelids
swelling of the eye;
conjunctivitis; Romans’s sign
Chronic disease is cardiomyopathy
mild case : extra systole心收縮
slight tachycardia心悸,心搏過速
Severe case: heart block partially or completely
cardiac failure
Some case: megaoesophagus巨食管; dysphagia 吞嚥困難
megacolon巨結腸
70. Diagnosis
Blood examination: isolation of T. cruzi from blood
direct examination; centrifugation help
parasites culture; NNN medium
rats inoculation; 10 days: blood diagnosis
60 days: cardiac tissues examined (amastigotes)
Xenodiagnosis:uninfected laboratory-breed reduviid bugs
動物接種診斷法feeding on patient; 2 weeks inoculation
examined for epimastigotes
Serological diagnosis:
indirect haemagglutination test
FAT
75. Trypanosoma cruzi
Treatment
Effective chemotherapy is not available
nitrofurans
pyrimethamine
primaquine
nitroimidazoles
allopurinol riboside
Symptomatic treatment for cardiac failure by standard drugs
Pace-maker implantation
Surgery in megaoesophagus and megacolon cases
76. Trypanosoma cruzi
Vector control
successful in Brazil
Urbanization: vector habitat elimination
Gentian violet 龍膽紫 (1:4000)
preventing blood (donor) transfusion infection
Prevention and control
77.
78.
79. Flagellates 鞭毛蟲
Terms Used in Relation to Flagellates(Intestinal, Genital and Blood)
Flagellum鞭毛 –roma An elongated, hair-like organelle used
for locomotion. At the ultrastructural level, 1 pair of central
tubules and 9 pairs of peripheral tubules are visible.
Undulating membrane 波動膜 – A membranous structure
which connects the flagellum to the body of the parasite. It is
thrown into folds as the parasite moves, giving itan
undulating appearance.
Costa 肋– A cytoplasmic thickening seen at the base of the
undulating membrane in some flagellates.
Axostyle 軸柱 – A central supporting rod seen in some
flagellates.
80. Amastigote 無鞭毛體– Also known as the leishmanial stage.
It is round or oval in shape without any free flagella.
Promastigote 前鞭毛體 – Also known as the leptomonad stage.
It is elongated with kinetoplast anterior and distal to the
nucleus. The flagellum emerges from the anterior end. There
is no undulating membrane.
Epimastigote 側鞭毛體 – Also known as the crithidial stage.
It is elongated with the kinetoplast anterior and close to the
nucleus. There is a short undulating membrane.
Trypomastigote 錐鞭毛體 – Also known as the trypanosome
stage. It is elongated with the kinetoplast posterior and distal
to the nucleus. There is a long undulating membrane.
81. Axoneme 軸絲 – A delicate filament extending from the
region of the kinetoplast to the cell membrane. It represents
the cytoplasmic part of the flagellum.
Kinetoplast 動基體– An oval or rod-shaped body seen in
haemoflagellates. It stains with nuclear dyes and contains
DNA. It is regarded as a modified part of the
mitochondrium.
Pleomorphic 多形性 – When a number of morphological
types occur in one life cycle.
Monomorphic 單形性 – When a single morphological type
occurs in one life cycle.
Metacyclic trypanosome – Infective forms of trypanosomes
which develop in the vector.
82. Xenodiagnosis 病媒接種診斷 – A method of diagnosis in
which a vector is fed on a suspected case and is later
examined for the presence of the parasite.
Peritrophic membrane 圍食膜 – A membrne which is
secreted from the anterior end of the midgut in some blood-
feeding arthropods. This membrane encloses the blood meal.
Stercorian trypanosomes 糞內錐蟲 – Infective forms which
develop in the faeces of the insect vector and enter the
vertebrate host by contamination of the bite area. This is also
known as the anterior station development.
Salivarian trypanosomes 唾腺錐蟲 – Infective forms which
develop in the mouth parts or salivary glands and enter the
vertebrate host by inoculation during biting. This is also
known as the anterior station development.
83. Volutin granules – Small inclusions seen in the cytoplasm of
trypanosomes which stain red or purple with Romanovsky
stains. They are probably lysosomes.
Kissing bugs 錐鼻蟲 – Name given to biting bugs of the
family Redurviidae which transmit Trypanosoma cruzi,
become they frequently biet the face of sleeping people.
Tsetse fly 采采蠅 – Name given to biting flies of the genus
Glossina which transmit Trypanosoma gambiense and T
. rhodesiense.
Morula (mulberry) cells of Mott – These are altered plasma
cells with cytoplasm filled with proteinaceous droplets.
These are seen in brain tissues and characteristic of African
trypanosomiasis.
84. Kerandel’s sign – Seen in African trypanosomiasis and in
elicited by putting pressure on the palm of the hand. Severe
pain occurs shortly after the pressure has been removed.
Chiclero’s ulcer – A non-metastizing and long lasting skin
lesion which is usually located on the ear. Caused by
Leishmania mexicana.
Espundia 鼻咽性 – A skin lesion which subsides
spontaneously but later metastasizes to other areas. Caused
by Leishmania braziliences.
Uta – A skin lesion caused by Leishmania peruviana. It is
usually mild and self healing.
Oriental sore 東方瘡 – Cutaneous leishmaniasis of the old
world cased Leishmania tropica and Leishmania major.
Kala-azar 黑熱病 – Means black fever in Hindi (Indian).
Refers to infection caused by Leishmania donovani.
