Midterm Lab Practicum Flashcards
Entamoeba histolytica trophozoite
Entamoeba histolytica cysts
What is the life cycle of Entamoeba histolytica?
Cyst –> Excystation in small intestine –> metacystic amoeba
When is the infective stage of Entamoeba histolytica?
Cyst stage
Where are Entamoeba histolytica trophozoites found?
Large intestine and invade mucosa
How do you get infected with Entamoeba histolytica ?
Drinking fecal contaminated water
What is distribution of Entamoeba histolytica?
Worldwide distribution, but most common in tropical and subtropical areas
What is the source of Entamoeba histolytica?
Contaminated water, laundry, etc Contaminated food (vegetables, soil) Mechanical contamination (medical equipment)
What is pathology of Entamoeba histolytica?
Trophozoites adhere to epithelium –> forming an ulcer
Colitis (inflammation of colonic wall)
Liver lesions / abcess
Symptoms of Entamoeba histolytica
Diahrrea, dysentery, cramps, vomiting, malaise, abdominal discomfort
How do you diagnose Entamoeba histolytica?
Microscopy of pus or aspirate, stool examination
What is prognosis of Entamoeba histolytica?
90% recovery after treatment –> Metronidazole (10-25 mg/kg, PO,
bid x 1 wk)
Body will repair itself but repaired
connective tissue in bowel will not
function.
Entamoeba histolytica trophozoite
Entamoeba histolytica cyst
What is life cycle of Entamoeba coli?
Life cycle and location identical to Entamoeba histolytica
Is Entamoeba coli pathogenic?
No –> feeds on bacteria; does not invade tissue
Which is E. coli and which is E. histolytica?
Top –> E. coli
Bottom –> E. histolytica
Entamoeba coli cysts
How can you prevent Entamoeba infections?
1.Boil drinking water
2. Wash fruits and vegetables in clean water before eating
3. Detection and treatment of carriers and prohibit them
from food handling
4. Health education
What are the two main diseases Trypanosoma spp cause?
Sleeping sickness, Chaga’s dz
What is the main dz Plasmodium spp cause?
Malaria
Trypanosoma spp.:
•Sleeping sickness
•Chagas disease
Plasmodium spp.
•Malaria
- Leishmania spp.
* Leishmaniasi
Trichomonas spp.
•Trichomoniasis
Giardia spp.
•Giardiasis
What kind of hosts and vectors do Trypanosoma spp have?
vertebrate host and
invertebrate vector
Trypanosomiasis, African Sleeping sickness (African, Old World)
- Trypanosoma brucei gambiense
- Trypanosoma brucei rhodesiense
- Trypanosoma brucei brucei (cattle)
Trypanosome life cycle
Tstese fly takes blood meal –> injects trypomastigotes into human blood stream –> Trypomastiogotes multiply via binary fission –> fly takes blood meal
(cycle repeats)
Diagnosis of Trypanosomiasis
Detection and evidence in blood
Antibody detection
What trypanosome causes Chagas disease?
•Trypanosoma cruzi
Life cycle of Trypanosoma cruzi
Kissing bug takes blood meal –> trypomastigotes enter human bloodstream –> amastiogotes multiply via binary fission in infected tissues –> amastiogotes transform into trypomastiogotes –> Kissing bug takes blood meal
(cycle repeats)
Trypanosoma
Amastigote pseudocyst in cardiac muscle
How is Chaga’s disease diagnosed?
Finding of trypomastigotes in circulating blood or cerebral spinal
fluid (Acute)
Serology
Molecular detection
Prevention of African Trypanosomiasis
•Control of tsetse fly population (most important preventive measure) by wide spraying of insecticides, traps and baits impregnated with
insecticides.
•No vaccine is available.
Prevention of American Trypanosomiasis
•Application of insecticide to control the vector bug.
•Personal protection using insect repellant and mosquito net.
•Improvement in rural housing and environment to eliminate breeding
places of bugs.
What does Leishmania spp cause?
Causes visceral, mucocutaneous, and
cutaneous leishmaniasis in dogs,
people, and other animals
What is Leishmania transmitted by?
primarily by sandflies (vector)
Which are Leishmania and which are Trypanosoma?
Left –> Leishmania
Right –> Trypanosoma
Leishmania life cycle
Sandfly takes blood meal –> promastigotes are phagocytized –> transform into amastiogotes –> multiply and infect other cells –> sandfly takes blood meal –> ingestion of parasatized cell –> amastiogotes transform into promastiogotes in the gut
Leishmania symptoms
Some people have a silent infection, without any symptoms or
signs.
•After the initial bite from an infected sandfly, symptoms evident
as quick as 10 days, and up to a year.
•Usually is two to four months. `
Leishmania diagnosis
LD bodies, culture, molecular diagnosis
Prvention of Leishmania
Use of insect repellants, spraying of insecticides and screening are advisable.
•Forest workers should use protective clothing and other protective measures.
Giardia duodenalis
Giardia life cycle
Giardiasis
Giardiasis Diagnosis
- Stool examination
- Serology
- Molecular detection
Giardiasis Prevention
•Proper disposal of waste water and feces.
•Practice of personal hygiene like handwashing before eating and
proper disposal of diapers.
•Prevention of food and water contamination.
•Community chlorination of water is ineffective for inactivating cysts.
•Boiling of water and filtration by membrane filters
What does Trichomonas vaginalis cause?
vaginitis in women
How is Trichomonas vaginalis transmitted?
•Transmitted by sexual intercourse, with men playing the role of
asymptomatic carrier.
Trichomoniasis life cycle
Trophozoite in vaginal secretion –> multiplies by binary fission –> trophozoite in vagina/urethra
Trichomoniasis
Diagnosis of Trichomoniasis
symptoms, •wet mount, •permanent stain, •culture, •serology, •molecular diagnosis
Prevention of Trichomoniasis
- Avoidance of sexual contact with infected partners
* use of barrier method during intercourse
Apicomplexa
Parasites of cells: Intracellular
What spp causes malaria?
Plasmodium
What is malaria vector?
Mosquitos
Malaria life cycle
Transmission to human –> sprozoites enter liver –> mitotic replication –> cell ruptures –> transmission to mosquito –> sporozoites develop
Where do sporozoites and merozoites of malaria come from?
- Sporozoites injected by mosquito bite
- Reach the liver (damage the cells, multiply asexually and come back into the blood stream)
- Merozoites reach the RBC and transform in Trophozoite
Malaria –> Merozoites inside RBC
Malaria trophozoite inside RBC
Plasmodium vivax
P. vivax gametocytes
P. vivax schizonts
Malaria sporozoite
Symptoms of Malaria
Fever, nausea, vomitting, anemia and jaundice, kidney failure, death
Malaria diagnosis
Microscopic evidence
Blood smear-stained with Giemsa or Wright
Molecular diagnosis-PCR (spp. specific)
Antibody detection
Antigen detection
Malaria prevention
Full body clothing Sleeping in insecticide-covered mosquito nets Using insect sprays Empty out water collections (Anopheles spp. Lay their eggs in small collections of water)
Where is Eimeria found?
In digestive tracts of herbivores or carnivores causing diarrhoeal
disease
Three stages of coccidosis life cycle
- Sporulation: sporulated oocyst formation (IS)
Oocyst enclosing sporocyst, each containing sporozoites - Infection and merogony (schizogony) (Asexual reproduction): meront
(schizont) formation, containing merozoites - Gametogony and oocyst formation (Sexual reproduction)
Eimeria / coccidiosis
Eimeria / coccidiosis
Coccidiosis symptoms
Diarrhea (chronic-acute)
Bloody diarrhea, tenesmus
Recurrent episodes of illness in successive populations of
domestic and wild animals
In calves: besides intestinal manifestation, nervous coccidiosis
(convulsions, nystagmus, blindness, death)
Infection could remain inapparent, but oocysts may be shed for
several weeks or months
Coccidiosis diagnosis
Identification if oocyst in host’s feces
Gross and microscopic lesions in DT
Demonstration of sexual and asexual life stages in smear or histologic
techniques.
Coccidosis prevention
Cleaning of the facilities regularly
Ensuring good water quality and food
Drying and exposure to sunlight aids in the die-off of oocysts
Comparison
Early stage trophozoites
What does Helminth mean?
General term meaning worm
Trematodes
Flukes, flatworms
Cestodes
Tapeworms
Nematodes
Roundworms
Trematode general life cycle
Eggs –> Miracidium –> Redia –> Sporocyst –> Cecaria –> Metacercaria –> adult
What are the hosts of trematodes?
1st intermediate host –> gastropod (snail)
Definitive host –> always a vertebrate
Fasciola hepatica
Sheep liver fluke
What is definitive host of Fasciola hepatica ?
sheep, but also found in biliary tract in human
Fasciola hepatica
Fasiola hepatica egg
Fasciola hepatica adult
Fasciola spp life cycle
Eggs passed in feces –> eggs embryonated in water –> miracidia hatch from eggs –> go to snail IH –> Sporocyste –> rediae –> cercariae –> cercaria go on aquatic vegitation –> ingested by DH –> flukes excyst and migrate
Fasciola hepatica pathogenesis
Mechanical damage Severe inflammatory response fever, pain, eosinophilia, hepatomegaly biliary obstruction, cirrhosis, jaundice, cholelithiasis, anemia
Fasciola hepatica diagnosus
Stool microscopy, bloodsmear
Fasciola hepatica Prevention and control
Health education Control of snails Proper disposal of feces Proper disinfection of watercresses and other vegetations before consumption.
Paragonimus westermani
Oriental lung fluke
What is intermediate host of Paragonimus westermani?
Crab or crayfish
Paragonimus westermani life cycle
- ->1DH, 2 IH
- ->DH: human, and crab-eating mammals
- ->1st IH: freshwater snail Semisulcospira and Brotia genus
- ->2nd IH: freshwater crab or crayfish
- ->Infective form: metacercariae encysted in crab or crayfish
- ->Mode of infection: ingestion of metacercariae
Paragonimus westermani Morphology
Paragonimus westermani Pathogenesis and Clinical Features
–>Pulmonary features: lies in cystic spaces by fibrous capsule
–>In communication with bronchi
–>Inflammation -> peribronchial lesions, abscesses, eosinophilia.
–>Cough, chest pain, hemoptysis. Sputum with
eggs
–>Extrapulmonary features:
–>Abdominal paragonimiasis
–>Cerebral paragonimiasis
Paragonimus westermani Diagnosis
- ->Microscopy: demonstration of the eggs in sputum or feces
- ->Serology
- ->Imaging (chest X-ray)
Paragonimus westermani Prevention and control
-->Adequate cooking of crabs and crayfish and washing the hands after preparing them for food. -->Treatment of infected persons. -->Disinfection of sputum and feces. -->Eradication of molluscan hosts.
Clonorchis sinensis
Oriental liver fluke
Clonorchis sinensis distribution
Asia
What dies Clonorchis sinensis cause?
hepatic dz –> classified as carcinogenic
Clonorchis sinensis
Clonorchis sinensis
Clonorchis sinensis Morphology
Clonorchis sinensis Life cycle
–>1 DH, 2 IH
–>DH: humans, dogs, and other fish-eating canines act as
reservoir host
–>1st IH: snail
–>2nd IH: freshwater fish
–>Infective form: metacercaria larva in freshwater fish
–>Mode of infection: by eating undercooked fish carrying
metacercaria
Clonorchis sinensis Pathogenesis and Clinical Features
–>Many asymptomatic infections
–>Damage and inflammatory response due to migration of the
larva up the bile duct
–>Cholangitis by obstruction
–>Fever, epigastric pain, diarrhea,
hepatomegaly, jaundice
Chronic:
Calculus formation
Cirrhosis
Cholangiocarcinoma
Clonorchis sinensis Diagnosis
- ->Microscopy: eggs in feces or aspirated bile
- ->Serological test
- ->Imaging: US, X-ray
Clonorchis sinensis Prevention and control
- ->Proper cooking of fish
- ->Proper disposal of feces
- ->Control of snails
Cestodes
Tapeworms
Cestodes Key Concepts
Tape-like body; no body cavity or alimentary canal: absorb their
nutrients through their tegument.
Where are cestode proglottids formed from?
Formed in the neck –> most distal segments are filled with embryonated eggs
Pseudophylidae
Cyclophylidae
Cestodes
General Life Cycle
–>Requires 1 to 3 hosts
–>Both aquatic and terrestrial cycles
–>Generally, invertebrate/vertebrate first intermediate host, and
second/definitive vertebrate hosts
–>Accidental hosts present
–>First larval stage: Oncosphere
–>Second and third larval stage: different names depending on
the Order
Diphyllobothrium latum
“Fish tapeworm”, “broad tapeworm”
What is IH of Diphyllobothrium latum
cyclops and freshwater fish
Diphyllobothrium latum
Morphology
Diphyllobothrium latum
–>Adult: up to 10 meters long (strobila with 3,000-4,000 proglottids)
–>Fertilized eggs develop in uterus and are discharged through
the uterine pore
Diphyllobothrium latum
Life cycle
• DH: human, dog, cat and other fish-eating mammals
• 1st IH: freshwater copepod (Cyclops or Diaptomus)
• 2nd IH: freshwater fish
• Infective form: third stage larva (plerocercoid)
• Mode of infection: ingestion of raw or undercooked fish
containing plerocercoid larva
Diphyllobothrium latum
Pathogenicity and Clinical Features
–>Depends on the mass of the worm
–>Infection could be asymptomatic
–>Mechanical obstruction
–>Abdominal discomfort, diarrhea, nausea,
weakness, weight loss, anemia
–>Strands of proglottids passed in feces
–>Vitamin B12 deficiency
Diphyllobothrium latum
Diagnosis
- ->Stool microscopy looking for eggs and proglottids
- ->Serodiagnosis: coproantigen detection test
Diphyllobothrium latum
Prevention
- ->Proper cooking of fish
- ->Deep freezing of fish if it is to be consumed raw
- ->Prevention of fecal pollution of natural waters
- ->Periodical deworming of pet dogs and cats
Echinococcus spp.
“Dog tapeworm”, “hydatid worm”
Echinococcus granulosus
Key Concepts
• Causes hydatid cyst in human
• Small, compared with other cestodes
• Larval form is called hydatid cyst
(filled with fluid)
Echinococcus multilocularisKey Concepts
• Causes alveolar or multilocular hydatid disease in human • DH: foxes, dogs and cats • Rodents are the main IH • Liver is the most common location • Pain, obstructive jaundice • Surgery resection, and tx with albendazole
Echinococcus granulosus
Echinococcus granulosus
Echinococcus granulosus
Life cycle
• DH: dog, wolf, fox…
• IH: sheep and cattle
• Human acts as an accidental intermediate host
• Human gets infection after ingestion of the eggs: handlimg infected
dogs, or by eating raw vegetables or other contaminated food
Echinococcus granulosus
Pathogenicity and Clinical Features
- Most of the cases, asymptomatic
- Pressure effect by enlarging cyst
- Hepatomegaly, pain, obstructive jaundice
- Lung, kidney, and even cerebral locations
Echinococcus granulosus
Diagnosis
• Imaging • CT • US • MRI • Ex. of the cyst fluid looking for \_\_\_\_\_ (lung, kidney) • Serodiagnosis • Molecular diagnosis
Echinococcus granulosus
Prevention
–>Ensuring pet dogs do not eat animal carcass or offal
–>Periodical deworming of pet dogs
–>Personal hygiene after touching dogs
–>Alveolar echinococcosis can be prevented by avoiding
contact with wild animals such as foxes, coyotes, and dogs and
their fecal matter and by limiting the interactions between dogs
and rodent populations.
Taenia spp.
“Beef tapeworm”, “pork tapeworm”
Taeniasis
Key points
–>Human is DH for T. solium (pork tapeworm) and T. saginata (beef
tapeworm)
–>Taenia multiceps
DH: dog, wolf, fox
IH: herbivores
Human acts as an accidental host (ingestion of food contaminated with
dog feces with eggs
–>Larval stage is called coenurus, located in the CNS causing neurological
disorders
–>T. solium larval stage called cysticercus, cause cysticercosis in
humans
Taenia spp.
Taenia spp.
Taenia spp.
Taenia solium and T. saginata
Distribution and location
- ->Worldwide (religion, vegetarians)
- ->Adults are in small intestine
Taenia solium and T. saginata
Life cycle
- DH: human
- IH: pig or cow
- Infective stage: cysticercus and eggs
Taenia solium and T. saginata Life cycle
Taenia solium and T. saginata
Pathogenicity and Clinical Features
• Intestinal taeniasis (both): surprisingly, little inconvenience. If
symptomatic, digestive.
• Cysticercocis:
• Any organ or tissue
• Inflammatory response, fibrosis, death of the larva and calcification.
• Subcutaneous nodules (asymptomatic)
• Muscular cys.: myositis
• Neurocysticercosis: epilepsy, intracranial tension, psychiatric
disturbances, behavioral disorders
• Ocular cys.: blurred vision, loss of vision, uveitis, iritis, conjunctivitis.
Taenia spp.
Prevention
- ->Inspection for cysticerci in slaughterhouse in beef and pork
- ->Avoidance of eating raw or undercooked meat (56C x 5 min)
- ->Proper disposal of feces
- ->Detection and treatment of persons harboring adult worm
Acanthocephala
Thorny headed worms
Hosts of Acanthocephala
DH: vertebrates
IH: arthropods
Acanthocephala Life cycle
- Indirect: aquatic or terrestrial arthropod as IH
* Egg -> Acanthor -> Acanthela -> Cystacanth -> adult
Morphology of Acanthocephala
Top section –> Probiscus
Middle section –> neck
Bottom section –> Trunk
Acanthocephala
Moniliformis moniliformis
- DH: rodents, carnivores
* IH: various beetles and cockroaches
Macracanthorhynchus hirudinaceus
- DH: pigs, wild boar
* IH: various dung beetles and water beetles