هذا تجميعات مهمه كلي الجميع يستفيد منها وحتى الطلاب الي عندهم اختبار هيئة راح يستفيد منهها.......
1-parasites causing
external autoinfection only:
1- Entrobius. 2- Entamoebahistolytica. 3- Balantidiumcoli.
4- Giardia .
2-parasites causing internal autoinfection only:
* Capillariaphlippinensis.
3-parasites causing both external & internal autoinfection:
1- Hymenolepis nana.
2- Taenia solium. 3-
Strongyloides.
4- Cryptosporidium.
Parasites causing anaemia ?
1-Microcytic hypochromic anaemia ( iron
deficiency anaemia) :
*Mechanism: repeted blood loss → depletion of iron stores
by bone marrow.
e.g, 1- Schistosoma haematobium (terminal haematuria)
2- Schistosoma mansoni & S. japonicum (
dysentery & bleeding intestinal polyps).
3- Hookworms
“ Ancylostoma duodenale & Necator” ( suction of blood by worms
& bleeding from previous sites of attachment).
4- Trichuris
& Trichostrongylus “heavy infection” (suction of
blood by worms).
2-Macrocytic hyperchromic anaemia (megaloblastic) :
e.g, 1- Diphyllobothrium latum ( consumption
of Vit. B12).
2- Trichuris ( toxic effect on bone marrow).
3- Haemolytic anaemia:
1- Plasmodium spp.
2- Babesia microti & B.
divergens.
3- S. mansoni & Plasmodium ( hypersplenism).
4- African trypanosomes & P.
falciparum ( autoimmune haemolysis).
Aplastic anaemia :
1-
Leishmania donovani.
2-
African trypanosomes.
• Snail as an intermediate host for Trematoda ?
Snail
:
Intermediate
host for:
1-
Lymnaea cailliaudi.
2-
Lymnaea truncatula.
3-
Pirenella conica.
4-
Biomphalaria.
5-
Bulinus.
6-
Semisulcospira.
Fasciola gigantica.
Fasciola hepatica.
Heterophyes.
Schistosoma mansoni.
Schistosoma haematobium.
Schistosoma japonicum.
Role of snail as an intermediate host :
* In all Trematoda : Egg hatches in water → miracidium
penetrates the snail→ develops to
sporocyst → redia →
cercaria.
* Except in : 1- Heterophyes : egg is
swallowed by snail where hatching occurs.
2- Schistosoma
: No redia stage inside the snail.
• Ectopic lesions caused by Flukes (Trematoda) ?
·
Ectopic lesion :
lesion caused by Trematode adult or egg away from its
normal habitat.
І- Ectopic lesions
by adult fluke:
1- Fasciola:
Encysted metacercaria may reach skin , gastric; caecal or colonic wall →
develop to immature flukes.
2- Paragonimus:
Young flukes may migrate from the lung to liver ; spleen; lymph
nodes; genitalia ; muscles; intestinal wall or skin → cysts containing
adult worms.
ІІ- Ectopic
lesions by egg:
1- Heterophyes : Egg may reach blood &
passes as emboli to :
A- Brain: → cerebral infarction or haemorrage.
B- Lung: → pulmonary embolism.
C- Heart: → myocarditis .
2- Schistosomes : Egg may reach :
A- Brain: → cerebral infarction “ common in S. japonicum”.
B-
Spinal cord : →
paraplegia.
C-
Lung: → bilharzial core pulmonale.
• Parasites causing myositis ? ( 5 T)
1- Tissue cestodes:
·
Cysticercosis ( cysticercus
cellulosae of Taenia solium).
·
Sparganosis ( sparganum of Spirometra).
·
Coenurosis ( coenurus cerebralis
of Multicepis).
·
Hydatid disease ( hydatid cyst of Echinococcus).
2- Trichinella spiralis.
3- Toxocara canis (visceral larva migrans).
4- Toxoplasma gondii.
5- Trypanosoma cruzi.
• Parasites causing appendicitis ?
1- Ascaris (erratic worms).
2- Entrobius.
3- Trichuris.
4- Entamoeba histolytica.
5- Balantidium coli.
• Parasites that can be detected in urine ?
1-
Schistosoma haematobium eggs.
2-
Wuchereria bancrofti microfilaria.
3-
Trichomonas vaginalis trophozoite.
4-
Hydatid
sand (ruptured renal hydatid cyst).
5-
Toxocara canis larva
(visceral larva migrans).
6-
Entrobius eggs &
adult females (ectopic lesion).
7-
Larvae
(maggots) of Sarcophaga; Musca & Fannia (urogenital myiasis).
• Parasites that can be detected in CSF ?
І- Helminths : ( Nematode
larvae)
1- Toxocara canis
larva (visceral larva migrans).
2- Trichinella
spiralis larva (migration stage).
3-Strongyloides filariform larva ( in disseminated hyperinfection
syndrome in immunosuppression).
ІІ- Protozoa :
1- Naegleria fowleri trophozoites (amoeboid form).
2- Trypanosoma gambiense & T.
rhodesiense in cerebral invasion stage ( trypomastigote
form).
3- Toxoplasma tachyzoites (inimmunosuppression).
• Parasites that can inhabit biliary passages & gall bladder ?
1-
Fasciola
gigantica & F. hepatica adult.
2-
Ascaris
(erratic worms).
3-
Giardia
trophozoites.
4-
Cryptosporidium
(inimmunosuppression
).
• Filariform larva is the infective stage of some nematodes; enumerate them
& mention mode of infection in each.
1-
Ancylostoma duodenale ( skin penetration –
transmammary).
2-
Necator ( skin penetration).
3-
Strongyloides ( skin penetration – external & internal
autoinfection).
4-
Ancylostoma braziliensis ; A. caninum & non-human Strongyloides → cutaneous
larva migrans( skin penetration).
5-
Filaria (skin penetration through insect bite) e.g;
*Wuchereria bancrofti...........................Culex.
*Brugyia malayi…………………………..Mansonia.
*Loa loa………………………………….Chrysops.
*Onchocerca volvulus…………………Simulium.
*Mansonella ozzardi& M.perstans.....Culicoides.
6- Trichostrongylus ( ingestion of filariform larva
with raw vegetables).
7- Dracunculus
medinensis(ingestion of filariform larva within Cyclops).
• Loffler’s syndrome : “definition, causative parasites; C/P & diagnosis” ?
*definition: It is verminous pneumonitis caused by
migrating larvae of some helminths.
* causative parasites:
1-
Schistosomes.
2-
Ascaris.
3-
Hookworms ( Ancylostoma duodenale & Necator).
4-
Strongyloides.
* C/P: fever; cough; expectoration; haemoptysis &
eosinophilia.
* diagnosis:
1-
Chest X- ray: milliary opacities in the lung.
2-
Sputum examination : larvae &
Charcot – Leyden crystals.
3-
Blood examination :
eosinophilia.
• Parasites infecting man through meat consumption:
Type of meat
Parasite name/disease
Infective stage
1- Beef
Taenia saginata
Cysticercus bovis.
2- Pork.
• Taenia solium
•Trichinella spiralis
•Toxoplasma
Cysticercus cellulosae.
Encysted larva.
Tissue cyst “containing
trophozoites”.
3- Fish.
• Heterophyes
•Paragonimus
•D. latum
•Capillaria
phleppinensis
Encysted metacercaria.
Encysted metacercaria.
Plerocercoid.
Infective larva.
4- Frog.
Spirometra mansoni→
sparganosis. adult.
Sparganum larva.
5- Liver.
Halzoun
Viable Fasciola adult.
• Mention sex modes
of infection by parasites with examples;
1- Ingestion : (Oral route)e.g;
·
Ascaris “ ingestion
of raw vegetables contaminated with embryonated egg”.
·
Oxyuris “ soiled
fingers”.
2- skin penetration : e.g;
·
Direct skin
penetration: as Schistosomes
“ through skin penetration with furcocercous cercaria”.
·
Through insect bite :
e.g; Filaria; Leishmania & Plasmodium.
3-
Blood transfusion :
e.g; Plasmodium & Babesia.
5- Congenital
“Transplacental “: e.g; Toxoplasma &
Trypanosomes.
6- Sexual : e.g;
Trichomonas vaginalis.
• Parasites that can be detected in blood film ?
І- Helminths :
1- Strongyloides filariform larva ( in disseminated hyperinfection in
immunosuppression).
2- Trichinella larva ( during migration stage).
3- Microfilaria of :
* Wuchereria bancrofti.
* Brugyia malayi.
* Loa loa .
* Mansonella persitans & ozzardi
ІІ- Protozoa :
1-
Plasmodium & Babesia.
2-
Trypanosoma gambiense & T. rhodesiense.
3-
Trypanosoma cruzi.
4-
Leishmania donovani & L. infantum.
5-
Toxoplasma .
• Parasites that may cause pruritus ani “Perianal itching”:
1- Entrobius (migrating
female worms & egg deposition at the
perianal skin).
2- Taenia saginata (passage of
gravid segment through the anus).
3- Ascaris (allergic reaction due to passage of adult worm through
the anus).
4- Strongyloides ( externally
autoinfective filariform larvae → larva currens).
• Parasites that may affect brain :
І- Helminths:
1- Schistosoma japonicum eggs.
2- Heterophyes eggs.
3- Cysticercus cellulosae (cysticercosis).
4- Hydatid cyst.
5- Sparganum of Spirometra
(sparganosis).
6- Coenurus cerebralis of Multiceps
(coenurosis).
7- Larvae of nematodes :
A-
Ascaris larva (visceral larva
migrans – like symptoms→meningism)
B-
Toxocara canis larva (visceral
larva migrans).
C-
Trichinella larva (migration
stage).
D-
Strongyloides filariform larva (
disseminated hyperinfection in immunosuppression).
8- Loa loa (heavy infection
after DEC therapy →meningoencephalitis).
ІІ- Protozoa:
1- Entamoeba histolytica (amoebic brain abscess).
2- Naegleria (PAM).
3- Acanthamoeba
(GAE).
4- Trypanosoma gambiense & T. rhodesiense (sleeping sickness).
5- Trypanosoma cruzi (meningoencephalitis).
6- Plasmodium falciparum (cerebral malaria).
7- Toxoplasma (encephalitis).
ІІІ- Arthropods:
*
Chrysomyia larvae (causing aural myiasis) may reach the brain.
• Parasites causing hyperpigmentation of
skin (3V):
1- Onchocerca volvulus (Sowda ).
2- Leishmania
donovani ( grayish discoloration of skin of face & hands →black fever).
3- Heavy
infestataion with Pediculus (Vagabond
disease).
• Parasites causing splenomegaly :
1- Schistosoma mansoni.
2- Toxocara canis (visceral larva migrans).
3- Wuchereria bancrofti & B.malayi (tropical pulmonary eosinophilia).
4- Plasmodium ovale; vivax
&falciparum (hyperactive
malarial splenomegaly).
5- Leishmania donovani & infantum.
6- Trypanosome cruzi.
■ Hyperinfection : definition; parasitic causes & mechanism ?
•
Hyperinfection : means massive
increase in the worm burden (i.e. parasite number) within the host as a result
of uncontrolled internal autoinfection.
• Parasitic
causes :
1- Strongyloides stercoralis (Opportunistic
parasite):
*Mechanism: in immunosuppressed
individuals; most of rhabditiform larvae develop into filariform (infective) larvae in the
lumen of the intestine → penetrate intestinal mucosa → migrate through the lung
→ ascend along bronchial tree → coughed ; swallowed & develop into adult
worms (repeated internal autoinfection → hyperinfection).
2-
Capillaria philippinensis (virulent
parasite):
*Mechanism: in immunocompetent
individuals; untreated infection will result in embryonation of eggs in the
intestinal lumen→ hatch → infective larvae penetrate intestinal mucosa→ develop
to adult worms (repeated internal autoinfection → hyperinfection).
• Man may act as a blind host
(dead-end) for some parasitic infections:
·
Blind
host: a host that can be infected but cannot
infect others.
·
Man
acts as a blind host in:
1-
All
tissue cestodes (Hydatid
disease; cysticercosis; sparganosis & coenurosis).
2-
Trichinella spiralis.
3-
Visceral & cutaneous larva migrans.
4-
Babesiosis (man –to –Tick infection does not occur
; but, man – to – man infection can occur by blood transfusion).
• Parasites
infecting man through skin penetration ?
A-
Cercaria: as Schistosomes.
B-
Sparganum larva:
as Spirometra mansoni & S. proliferum (when infected raw flesh of
frog or snake used as foments for skin wound).
C-
Filariform larva:
either through:
І- Direct skin
penetration: e.g;
1-
Hookworms
( Ancylostoma duodenale & Necator).
2-
Strongyloides.
3-
Ancylostoma
caninum ; A. braziliensis
& non-human Strongyloides (→
cutaneous larva migrans).
ІІ- Insect bite: e.g; all filaria ;
*Wuchereria
bancrofti...........................Culex.
*Brugyia
malayi…………………………..Mansonia.
*Loa
loa………………………………….Chrysops.
*Onchocerca
volvulus…………………Simulium.
*Mansonella
ozzardi& M.perstans.....Culicoides.
D-
Protozoa : (through arthropod
bite);
1- Leishmania ……………………..Sand
fly.
2- Trypanosoma
gambiense & T. rhodesiense…….Glossina.
3- Trypanosoma cruzi
……………. Triatoma.
4- Plasmodium
…………………….Female Anopheles.
5- Babesia…………………………..Hard
tick.
E- Arthropods: either:
1-
Larvae (maggots) of flies: e.g;
larvae of Hypoderma;
Dermatobia & Gastrophilus (Cutaneous myiasis).
2- Arthropod itself :
e.g;
і- Tunga
penetrans (chigger flea).
іі-
Sarcoptes scabiei (→ scabies).
ііі-
Demodex.
• Parasites that may affect Lung :
І- Helminths:
1- Paragonimus
(adult).
2- Heterophyes (ectopic
egg).
3- Schistosomes
(ectopic egg or migrating schistosomula).
4- Hydatid cyst.
5- Migrating larva of
nematodes: e.g;
* Nematodes causing Loffler’s
syndrome (Ascaris; Hookworms & Strongyloides).
* Trichinella spiralis.
6- W.bancrofti & B. malayi
(tropical pulmonary eosinophilia).
ІІ- Protozoa:
1- E. histolytica (extraintestinal amoebiasis).
2- Acanthamoeba (primary lesion).
3- Leishmania donovani & L. infantum.
4- Toxoplasma.
5- Plasmodium falciparum (Acute pulmonary oedema).
6- Cryptosporidium (in AIDS patients).
7- Pneumocystis.
ІІІ- Arthropods:
• Dermatophagoides (house dust mites) → bronchial asthma.
• Role of “flies” in transmission of parasitic diseases ?
І- Mechanical
transmission
i.e. No
multiplication or developmental changes of parasite in the fly).
e.g; 1- Musca
: transmits H.nana; T.solium & Entrobius eggs.
2- Stomoxys :
transmits African Trypanosomes.
ІІ- Biological
transmission: (i.e. multiplication and/or developmental changes of
parasite in the fly).
e.g; 1- Flies
transmitting Filaria: (cyclodevelopmental transmission)
* Chrysops transmits Loa loa.
* Simulium transmits Onchocerca volvulus.
* Culicoides transmit Mansonella ozzardi & M.perstans.
2- Flies transmitting protozoa :
(cyclopropagative transmission)
* Sand fly transmits
Leishmania
* Glossina transmits
Trypanosoma gambiense & T. rhodesiense
1-parasites causing
external autoinfection only:
1- Entrobius. 2- Entamoebahistolytica. 3- Balantidiumcoli.
4- Giardia .
2-parasites causing internal autoinfection only:
* Capillariaphlippinensis.
3-parasites causing both external & internal autoinfection:
1- Hymenolepis nana.
2- Taenia solium. 3-
Strongyloides.
4- Cryptosporidium.
Parasites causing anaemia ?
1-Microcytic hypochromic anaemia ( iron
deficiency anaemia) :
*Mechanism: repeted blood loss → depletion of iron stores
by bone marrow.
e.g, 1- Schistosoma haematobium (terminal haematuria)
2- Schistosoma mansoni & S. japonicum (
dysentery & bleeding intestinal polyps).
3- Hookworms
“ Ancylostoma duodenale & Necator” ( suction of blood by worms
& bleeding from previous sites of attachment).
4- Trichuris
& Trichostrongylus “heavy infection” (suction of
blood by worms).
2-Macrocytic hyperchromic anaemia (megaloblastic) :
e.g, 1- Diphyllobothrium latum ( consumption
of Vit. B12).
2- Trichuris ( toxic effect on bone marrow).
3- Haemolytic anaemia:
1- Plasmodium spp.
2- Babesia microti & B.
divergens.
3- S. mansoni & Plasmodium ( hypersplenism).
4- African trypanosomes & P.
falciparum ( autoimmune haemolysis).
Aplastic anaemia :
1-
Leishmania donovani.
2-
African trypanosomes.
• Snail as an intermediate host for Trematoda ?
Snail
:
Intermediate
host for:
1-
Lymnaea cailliaudi.
2-
Lymnaea truncatula.
3-
Pirenella conica.
4-
Biomphalaria.
5-
Bulinus.
6-
Semisulcospira.
Fasciola gigantica.
Fasciola hepatica.
Heterophyes.
Schistosoma mansoni.
Schistosoma haematobium.
Schistosoma japonicum.
Role of snail as an intermediate host :
* In all Trematoda : Egg hatches in water → miracidium
penetrates the snail→ develops to
sporocyst → redia →
cercaria.
* Except in : 1- Heterophyes : egg is
swallowed by snail where hatching occurs.
2- Schistosoma
: No redia stage inside the snail.
• Ectopic lesions caused by Flukes (Trematoda) ?
·
Ectopic lesion :
lesion caused by Trematode adult or egg away from its
normal habitat.
І- Ectopic lesions
by adult fluke:
1- Fasciola:
Encysted metacercaria may reach skin , gastric; caecal or colonic wall →
develop to immature flukes.
2- Paragonimus:
Young flukes may migrate from the lung to liver ; spleen; lymph
nodes; genitalia ; muscles; intestinal wall or skin → cysts containing
adult worms.
ІІ- Ectopic
lesions by egg:
1- Heterophyes : Egg may reach blood &
passes as emboli to :
A- Brain: → cerebral infarction or haemorrage.
B- Lung: → pulmonary embolism.
C- Heart: → myocarditis .
2- Schistosomes : Egg may reach :
A- Brain: → cerebral infarction “ common in S. japonicum”.
B-
Spinal cord : →
paraplegia.
C-
Lung: → bilharzial core pulmonale.
• Parasites causing myositis ? ( 5 T)
1- Tissue cestodes:
·
Cysticercosis ( cysticercus
cellulosae of Taenia solium).
·
Sparganosis ( sparganum of Spirometra).
·
Coenurosis ( coenurus cerebralis
of Multicepis).
·
Hydatid disease ( hydatid cyst of Echinococcus).
2- Trichinella spiralis.
3- Toxocara canis (visceral larva migrans).
4- Toxoplasma gondii.
5- Trypanosoma cruzi.
• Parasites causing appendicitis ?
1- Ascaris (erratic worms).
2- Entrobius.
3- Trichuris.
4- Entamoeba histolytica.
5- Balantidium coli.
• Parasites that can be detected in urine ?
1-
Schistosoma haematobium eggs.
2-
Wuchereria bancrofti microfilaria.
3-
Trichomonas vaginalis trophozoite.
4-
Hydatid
sand (ruptured renal hydatid cyst).
5-
Toxocara canis larva
(visceral larva migrans).
6-
Entrobius eggs &
adult females (ectopic lesion).
7-
Larvae
(maggots) of Sarcophaga; Musca & Fannia (urogenital myiasis).
• Parasites that can be detected in CSF ?
І- Helminths : ( Nematode
larvae)
1- Toxocara canis
larva (visceral larva migrans).
2- Trichinella
spiralis larva (migration stage).
3-Strongyloides filariform larva ( in disseminated hyperinfection
syndrome in immunosuppression).
ІІ- Protozoa :
1- Naegleria fowleri trophozoites (amoeboid form).
2- Trypanosoma gambiense & T.
rhodesiense in cerebral invasion stage ( trypomastigote
form).
3- Toxoplasma tachyzoites (inimmunosuppression).
• Parasites that can inhabit biliary passages & gall bladder ?
1-
Fasciola
gigantica & F. hepatica adult.
2-
Ascaris
(erratic worms).
3-
Giardia
trophozoites.
4-
Cryptosporidium
(inimmunosuppression
).
• Filariform larva is the infective stage of some nematodes; enumerate them
& mention mode of infection in each.
1-
Ancylostoma duodenale ( skin penetration –
transmammary).
2-
Necator ( skin penetration).
3-
Strongyloides ( skin penetration – external & internal
autoinfection).
4-
Ancylostoma braziliensis ; A. caninum & non-human Strongyloides → cutaneous
larva migrans( skin penetration).
5-
Filaria (skin penetration through insect bite) e.g;
*Wuchereria bancrofti...........................Culex.
*Brugyia malayi…………………………..Mansonia.
*Loa loa………………………………….Chrysops.
*Onchocerca volvulus…………………Simulium.
*Mansonella ozzardi& M.perstans.....Culicoides.
6- Trichostrongylus ( ingestion of filariform larva
with raw vegetables).
7- Dracunculus
medinensis(ingestion of filariform larva within Cyclops).
• Loffler’s syndrome : “definition, causative parasites; C/P & diagnosis” ?
*definition: It is verminous pneumonitis caused by
migrating larvae of some helminths.
* causative parasites:
1-
Schistosomes.
2-
Ascaris.
3-
Hookworms ( Ancylostoma duodenale & Necator).
4-
Strongyloides.
* C/P: fever; cough; expectoration; haemoptysis &
eosinophilia.
* diagnosis:
1-
Chest X- ray: milliary opacities in the lung.
2-
Sputum examination : larvae &
Charcot – Leyden crystals.
3-
Blood examination :
eosinophilia.
• Parasites infecting man through meat consumption:
Type of meat
Parasite name/disease
Infective stage
1- Beef
Taenia saginata
Cysticercus bovis.
2- Pork.
• Taenia solium
•Trichinella spiralis
•Toxoplasma
Cysticercus cellulosae.
Encysted larva.
Tissue cyst “containing
trophozoites”.
3- Fish.
• Heterophyes
•Paragonimus
•D. latum
•Capillaria
phleppinensis
Encysted metacercaria.
Encysted metacercaria.
Plerocercoid.
Infective larva.
4- Frog.
Spirometra mansoni→
sparganosis. adult.
Sparganum larva.
5- Liver.
Halzoun
Viable Fasciola adult.
• Mention sex modes
of infection by parasites with examples;
1- Ingestion : (Oral route)e.g;
·
Ascaris “ ingestion
of raw vegetables contaminated with embryonated egg”.
·
Oxyuris “ soiled
fingers”.
2- skin penetration : e.g;
·
Direct skin
penetration: as Schistosomes
“ through skin penetration with furcocercous cercaria”.
·
Through insect bite :
e.g; Filaria; Leishmania & Plasmodium.
3-
Blood transfusion :
e.g; Plasmodium & Babesia.
5- Congenital
“Transplacental “: e.g; Toxoplasma &
Trypanosomes.
6- Sexual : e.g;
Trichomonas vaginalis.
• Parasites that can be detected in blood film ?
І- Helminths :
1- Strongyloides filariform larva ( in disseminated hyperinfection in
immunosuppression).
2- Trichinella larva ( during migration stage).
3- Microfilaria of :
* Wuchereria bancrofti.
* Brugyia malayi.
* Loa loa .
* Mansonella persitans & ozzardi
ІІ- Protozoa :
1-
Plasmodium & Babesia.
2-
Trypanosoma gambiense & T. rhodesiense.
3-
Trypanosoma cruzi.
4-
Leishmania donovani & L. infantum.
5-
Toxoplasma .
• Parasites that may cause pruritus ani “Perianal itching”:
1- Entrobius (migrating
female worms & egg deposition at the
perianal skin).
2- Taenia saginata (passage of
gravid segment through the anus).
3- Ascaris (allergic reaction due to passage of adult worm through
the anus).
4- Strongyloides ( externally
autoinfective filariform larvae → larva currens).
• Parasites that may affect brain :
І- Helminths:
1- Schistosoma japonicum eggs.
2- Heterophyes eggs.
3- Cysticercus cellulosae (cysticercosis).
4- Hydatid cyst.
5- Sparganum of Spirometra
(sparganosis).
6- Coenurus cerebralis of Multiceps
(coenurosis).
7- Larvae of nematodes :
A-
Ascaris larva (visceral larva
migrans – like symptoms→meningism)
B-
Toxocara canis larva (visceral
larva migrans).
C-
Trichinella larva (migration
stage).
D-
Strongyloides filariform larva (
disseminated hyperinfection in immunosuppression).
8- Loa loa (heavy infection
after DEC therapy →meningoencephalitis).
ІІ- Protozoa:
1- Entamoeba histolytica (amoebic brain abscess).
2- Naegleria (PAM).
3- Acanthamoeba
(GAE).
4- Trypanosoma gambiense & T. rhodesiense (sleeping sickness).
5- Trypanosoma cruzi (meningoencephalitis).
6- Plasmodium falciparum (cerebral malaria).
7- Toxoplasma (encephalitis).
ІІІ- Arthropods:
*
Chrysomyia larvae (causing aural myiasis) may reach the brain.
• Parasites causing hyperpigmentation of
skin (3V):
1- Onchocerca volvulus (Sowda ).
2- Leishmania
donovani ( grayish discoloration of skin of face & hands →black fever).
3- Heavy
infestataion with Pediculus (Vagabond
disease).
• Parasites causing splenomegaly :
1- Schistosoma mansoni.
2- Toxocara canis (visceral larva migrans).
3- Wuchereria bancrofti & B.malayi (tropical pulmonary eosinophilia).
4- Plasmodium ovale; vivax
&falciparum (hyperactive
malarial splenomegaly).
5- Leishmania donovani & infantum.
6- Trypanosome cruzi.
■ Hyperinfection : definition; parasitic causes & mechanism ?
•
Hyperinfection : means massive
increase in the worm burden (i.e. parasite number) within the host as a result
of uncontrolled internal autoinfection.
• Parasitic
causes :
1- Strongyloides stercoralis (Opportunistic
parasite):
*Mechanism: in immunosuppressed
individuals; most of rhabditiform larvae develop into filariform (infective) larvae in the
lumen of the intestine → penetrate intestinal mucosa → migrate through the lung
→ ascend along bronchial tree → coughed ; swallowed & develop into adult
worms (repeated internal autoinfection → hyperinfection).
2-
Capillaria philippinensis (virulent
parasite):
*Mechanism: in immunocompetent
individuals; untreated infection will result in embryonation of eggs in the
intestinal lumen→ hatch → infective larvae penetrate intestinal mucosa→ develop
to adult worms (repeated internal autoinfection → hyperinfection).
• Man may act as a blind host
(dead-end) for some parasitic infections:
·
Blind
host: a host that can be infected but cannot
infect others.
·
Man
acts as a blind host in:
1-
All
tissue cestodes (Hydatid
disease; cysticercosis; sparganosis & coenurosis).
2-
Trichinella spiralis.
3-
Visceral & cutaneous larva migrans.
4-
Babesiosis (man –to –Tick infection does not occur
; but, man – to – man infection can occur by blood transfusion).
• Parasites
infecting man through skin penetration ?
A-
Cercaria: as Schistosomes.
B-
Sparganum larva:
as Spirometra mansoni & S. proliferum (when infected raw flesh of
frog or snake used as foments for skin wound).
C-
Filariform larva:
either through:
І- Direct skin
penetration: e.g;
1-
Hookworms
( Ancylostoma duodenale & Necator).
2-
Strongyloides.
3-
Ancylostoma
caninum ; A. braziliensis
& non-human Strongyloides (→
cutaneous larva migrans).
ІІ- Insect bite: e.g; all filaria ;
*Wuchereria
bancrofti...........................Culex.
*Brugyia
malayi…………………………..Mansonia.
*Loa
loa………………………………….Chrysops.
*Onchocerca
volvulus…………………Simulium.
*Mansonella
ozzardi& M.perstans.....Culicoides.
D-
Protozoa : (through arthropod
bite);
1- Leishmania ……………………..Sand
fly.
2- Trypanosoma
gambiense & T. rhodesiense…….Glossina.
3- Trypanosoma cruzi
……………. Triatoma.
4- Plasmodium
…………………….Female Anopheles.
5- Babesia…………………………..Hard
tick.
E- Arthropods: either:
1-
Larvae (maggots) of flies: e.g;
larvae of Hypoderma;
Dermatobia & Gastrophilus (Cutaneous myiasis).
2- Arthropod itself :
e.g;
і- Tunga
penetrans (chigger flea).
іі-
Sarcoptes scabiei (→ scabies).
ііі-
Demodex.
• Parasites that may affect Lung :
І- Helminths:
1- Paragonimus
(adult).
2- Heterophyes (ectopic
egg).
3- Schistosomes
(ectopic egg or migrating schistosomula).
4- Hydatid cyst.
5- Migrating larva of
nematodes: e.g;
* Nematodes causing Loffler’s
syndrome (Ascaris; Hookworms & Strongyloides).
* Trichinella spiralis.
6- W.bancrofti & B. malayi
(tropical pulmonary eosinophilia).
ІІ- Protozoa:
1- E. histolytica (extraintestinal amoebiasis).
2- Acanthamoeba (primary lesion).
3- Leishmania donovani & L. infantum.
4- Toxoplasma.
5- Plasmodium falciparum (Acute pulmonary oedema).
6- Cryptosporidium (in AIDS patients).
7- Pneumocystis.
ІІІ- Arthropods:
• Dermatophagoides (house dust mites) → bronchial asthma.
• Role of “flies” in transmission of parasitic diseases ?
І- Mechanical
transmission
i.e. Nomultiplication or developmental changes of parasite in the fly).
e.g; 1- Musca
: transmits H.nana; T.solium & Entrobius eggs.
2- Stomoxys :
transmits African Trypanosomes.
ІІ- Biological
transmission: (i.e. multiplication and/or developmental changes of
parasite in the fly).
e.g; 1- Flies
transmitting Filaria: (cyclodevelopmental transmission)
* Chrysops transmits Loa loa.
* Simulium transmits Onchocerca volvulus.
* Culicoides transmit Mansonella ozzardi & M.perstans.
2- Flies transmitting protozoa :
(cyclopropagative transmission)
* Sand fly transmits
Leishmania
* Glossina transmits
Trypanosoma gambiense & T. rhodesiense
