Medicine

METHODICAL INSTRUCTION FOR STUDENTS OF THE MEDICAL BIOLOGY, PARASITOLOGY AND GENETIC COURSE

METHODICAL INSTRUCTION FOR STUDENTS

ON MEDICAL BIOLOGY

Speciality “Nurse”

(distant form of studies)

 

LESSON № 5

Theme: Medical Helminthology. Phylum Plathelminthes. Classes Trematoda and Сestoidea. Phylum Nemathelmithes. Class Nematoda.

 

Number of hours: 6

Aim: to know general characteristics of phylum Plathyhelminthes, morphological peculiarities, life cycles and pathogenic significance of helminthes of class Trematoda and Cestoda; be able to determine their reference to species, to ground the methods of laboratory diagnostics and prophylactics of schistomiasis, paragonimiasis, clonorchiasis, fascioliasis, opisthorchiasis, dicrocoeliasis, teniasis solium, cysticercosis, taeniasis saginata, diphyllobothriasis.

To know morphological peculiarities, life cycles and pathogenic significance of Ascaris lumbricoides,  Enterobius vermicularis,  Trichuris trichiura, Trichinella spiralis, Ancylostoma duodenale, Necator americanus, Strongyloides stercoralis; be able to determine their reference to species, to ground the methods of laboratory diagnostics and prophylactics of ascariasis, enterobiasis, trichuriasis, trichinosis, ancylostomiasis, strongyloidiasis.

Professional orientation of students: Schistosomiasis, paragonimiasis, clonorchiasis are tropical diseases. Schisthosoma are affect about 1 in 20 of the world's population, more than 300 million people throughout Asia, Africa, Latin America, and the Middle East.  Some 800,000 people die each year from this disease.  Clonorchis sinensis affects about 20 million people. Biliary flukes cause cholecystitis, cholelithiasis, hepatic colic, cirrhosis of the liver. Most species of tapeworms occur in the intestines of vertebrates, about a dozen of them – regularly in humans. Ascariasis has a world-wide distribution and is particularly common in regions with poor or no sanitation. Enterobiasis is the most common helminthiasis in the world. More than 500 million people are affected by whipworm infection (trichuriasis).   Hookworm is found worldwide, especially in tropical areas. The global prevalence of hookworm infections probably is greater than the past estimate of nearly 500 million. 

 

Methodology of Practical Class:(900 – 1200).

Task 1. Biliary (liver) flukes. Fasciola hepatica

Sketch it in the notebook. Make following designations: Anterior and ventral suckers, uterus, testis.


 

 

Fasciola hepatica:

1.

2.

3.

4.


 

Examine slide of Fasciola hepatica eggs. Draw ovum of this helminth. Mark operculum and membrane.

 


 

Fasciola hepatica egg:

1.

2.


Study the life-cycle of Fasciola hepatica. Note stages of parasite development and their habitat.


 

 

Development stage

Habitat

A

 

 

B

 

 

C

 

 

D

 

 

E

 

 

F

 

 

G

 

 

 


 

Give the characteristics of Fasciola hepatica.

Invasive stage for a man - _______________________________________________________

Laboratory diagnosis - __________________________________________________________

Prevention - __________________________________________________________________

 

Task 2. Lanceolate fluke - Dicrocelium lanceatum.

Sketch it in the notebook. Make following designations: Anterior and ventral suckers, testis.


 

 

 

Dicrocelium lanceatum:

1.

2.

3.


Study the life-cycle of Dicrocelium lanceatum. Note stages of parasite development and their habitat.


 

Development stage

Habitat

1

 

 

2

 

 

3

 

 

4

 

 

5

 

 

6

 

 

 


Give the characteristics of Dicrocelium lanceatum.

Invasive stage for a man - _______________________________________________________

Laboratory diagnosis - __________________________________________________________

Prevention - __________________________________________________________________

 

Task 3. Cat fluke - Opisthorchis felineus.

Sketch it in the notebook. Make following designations: anterior and ventral suckers, testis.


 

 

Opisthorchis felineus:

1.

2.

3.


Study the life-cycle of Opisthorchis felineus. Note stages of parasite development and their habitat.


 

Development stage

Habitat

1

 

 

2

 

 

3

 

 

4

 

 

5

 

 

6

 

 

7

 

 

8

 

 

 


Give the characteristics of Opisthorchis felineus.

Invasive stage for a man - _______________________________________________________

Laboratory diagnosis - __________________________________________________________

Prevention - ___________________________________________________________________

 

Task 4. Write the differences between pathogenic species of Trematodes in the table.

Characteristics

Fasciola hepatica

Dicrocelium lanceatum

Opisthorchis felineus

Paragonimus westermani

Parasites of genus Shistosoma

Disease

 

 

 

 

 

Localization inside human body

 

 

 

 

 

Definitive host

 

 

 

 

 

Intermediate host

 

 

 

 

 

Route of transmission

 

 

 

 

 

Source of invasion

 

 

 

 

 

 

Task 5. Study the life-cycle of Taenia solium.(pork tapeworm) Note stages of parasite development.


 

Life-cycle of Taenia solium:

1.

2.

3.

4.

5.

6.

7.


Give the characteristics of  Taenia solium.

Invasive stage for a man - _______________________________________________________

Laboratory diagnosis - __________________________________________________________

Prevention - __________________________________________________________________

 

Task 6. Study the life-cycle of Taenia saginata (beef tapeworm). Note stages of parasite development.


 

Life-cycle of Taenia saginata:

1.

2.

3.

4.

5.

6.


Give the characteristics of Taenia saginata.

Invasive stage for a man - _______________________________________________________

Laboratory diagnosis - __________________________________________________________

Prevention - __________________________________________________________________

 

Task 7. Study the life-cycle of Diphyllobothrium latum, (fish tapeworm). Note stages of parasite development.


 

Life-cycle of Diphyllobothrium latum:

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.


Give the characteristics of Diphyllobothrium latum.

Invasive stage for a man - _______________________________________________________

Laboratory diagnosis - __________________________________________________________

Prevention - __________________________________________________________________

 

Task 8. Study the life-cycle of. Echinococcus granulosus (dog tapeworm). Note stages of parasite development.


 

 

Life-cycle of. Echinococcus granulosus:

1.

2.

3.

4.

5.

6.

7.

 

Give the characteristics of Echinococcus granulosus (dog tapeworm).

Invasive stage for a man - _______________________________________________________

Laboratory diagnosis - __________________________________________________________

Prevention - ___________________________________________________________________

 

Task 12. Enterobius vermicularis (pinworm) – the causative agent of Enterobiasis.

Study the life-cycle of Enterobius vermicularis. Note stages of parasite development.


 

 

Enterobius vermicularis:

1.

2.

3.

4.

 

 


 

Examine the slide of Enterobius vermicularis eggs under microscope (7 x 40). They are transparent and colorless, asymmetrical. Their membrane is thin and smooth. Sketch them. Mark membrane and larva.


 

 

Enterobius vermicularis egg:

1.

2.

 


 

Give the characteristics of Enterobius vermicularis.

Source of invasion _____________________________________________________________

Invasive stage for a man ________________________________________________________

Localization inside human body __________________________________________________

Pathogenicity _________________________________________________________________

_____________________________________________________________________________

Laboratory diagnosis ___________________________________________________________

Prevention ____________________________________________________________________

 

Task. 13 Ascaris lumbricoides  the causative agent of Ascariasis.

Study the life-cycle of Ascaris lumbricoides. Point out stages of its development.


 

 

 

Ascaris lumbricoides:

1.

2.

3.

4.

5.


The scheme of Ascaris larvae migration in the human body:

Intestine → ______________________ → ___________________________→ _________________________→ _________________________ → ___________________ → ___________________ → _____________________→ ______________________ → intestine.

 

Examine the slide of Ascaris lumbricoides eggs under a microscope (7 x 40). They are brown, oval or round form, covered by membranes. An external membrane is tuberous. Sketch. Mark membrane and larva.


Ascaris lumbricoides egg:

1.

2.


Give the characteristics of Ascaris lumbricoides.

Source of invasion _____________________________________________________________

Invasive stage for a man ________________________________________________________

Localization inside human body __________________________________________________

Pathogenicity _________________________________________________________________

_____________________________________________________________________________

Laboratory diagnosis ___________________________________________________________

Prevention ____________________________________________________________________

 

Task. 14. Trichuris trichiura (whipworm) – the causative agent of Trichuriasis.

Study the life-cycle of Trichuris trichiura. Note stage of parasite development.


 

 

Trichuris trichiura:

1.

2.

3.

4.


 

Examine the slide of Trichuris trichiura eggs under a microscope (7 x 40). The typical eggs are brown, barrel-shaped with a plug at each end. Sketch. Mark membrane, plug and larva.


 

Trichuris trichiura egg:

1.

2.

3.


Give the characteristics of Trichuris trichiura.

Source of invasion _____________________________________________________________

Invasive stage for a man ________________________________________________________

Localization inside human body __________________________________________________

Pathogenicity _________________________________________________________________

_____________________________________________________________________________

Laboratory diagnosis ___________________________________________________________

Prevention ____________________________________________________________________

 

 

Task 15. Trichinella spiralis – the causative agent of trichinosis

Examine the slide of encapsulated Trichinella spiralis larvae in cross-striated muscles of the rat under a microscope (7 x 8; 7 x 40). Sketch. Mark: 1-capsules, 2-muscles fibers, 3-Trichinella larvae.


 

 

Trichinella spiralis:

1.

2.

3.


 

Study the life-cycle of Trichinella spiralis. Note stage of parasite development and their location.


 

The life-cycle of Trichinella spiralis:

A

B

Development in pig organism

Development in human organism

1

 

 

2

 

 

3

 

 

4

 

 

5

 

 


Give the characteristics of Trichinella spiralis.

Source of invasion _____________________________________________________________

Invasive stage for a man ________________________________________________________

Localization inside human body __________________________________________________

Laboratory diagnosis ___________________________________________________________

Prevention ____________________________________________________________________


 

Seminar discussion of theoretical issues: (1230 - 1400).

Individual Students Program

1. Medical Helminthology. Phylum Plathelminthes. Classes Trematoda and Сestoidea.

1.                 General characteristic of class Trematoda.

2.                 Blood Flukes: Schistosoma haematobium, Schistosoma mansoni, Schistosoma japonicum.

3.                 Lung Fluke: Paragonimus westermani.

4.                 Biliary Flukes: Clonorchis sinensis, Fasciola hepatica, Opisthorchis felineus, Dicrocoelium lanceatum.

5. General characteristics of class Cestoda.

6.  Taenia saginata:  morphological peculiarities, distribution, life cycle, transmission, pathogenic significance.

7.   Taenia solium: morphological peculiarities, distribution, life cycle, transmission, pathogenic significance.

8.   Diphyllobotrium latum: morphological peculiarities, distribution, life cycle, transmission, pathogenic significance.

9.   Clinical manifestation and laboratory diagnosis of teniasis, cysticercosis,  diphyllobothriasis.

10.            Prevention of teniasis, cysticercosis, diphyllobothriasis.

2. Phylum Nemathelmithes. Class Nematoda.

1. General characteristics of Nematodes.

2.                 Ascaris lumbricoides, Enterobius vermicularis, Trichuris trichiura, Trichinella spiralis, hookworms, Strongyloides stercoralis: morphological peculiarities, distribution, life cycle, transmission, pathogenic significance.

3.   Laboratory diagnostics of ascariasis, enterobiasis, trichuriasis, trichinosis, ancylostomiasis, strongyloidiasis.

4.   Prevention of trichinosis, ancylostomiasis, strongyloidiasis, ascariasis, enterobiasis, trichuriasis.

 

Test evaluation and situational tasks.

Multiple Choices.

Choose the correct answer / statement:

1. Where do schistosomes lay fertilized eggs:

        A   bronchial tubes         B   intestine

        C   blood vessels        D   muscles            E   bile duct

2. A man, who came from Far East, passed a medical examination. Eggs (0,1 mm, oval, golden-brownish, operculated) were found in sputum. Indicate the most probable diagnosis:

A   fascioliasis         B   paragonimiasis      C   chlonorchiasis

               D   shistosomiasis      E ascariasis

3. Indicate parasites which exist as separate sexes but live attached to each other (female resides in a groove in the male, where he continuously fertilizes her eggs):

 A   schistosomes        B   Fasciola hepatica         C   Paragonimus westermani       

  D   Opisthorchis felineus         E  Ascaris lumbricoides

4. The life cycle of Clonorchis involves asexual reproduction in which animal:

 A   snail         B   crab         C   pig         D   fish            E   cattle

Real - life situations to be solved:

 5. A family has a cat with opisthorchiasis. Can children be infected with opisthorchiasis from this cat?

 6. Name organs of human body in blood vessels of which lay eggs

a) S.haematobium;  b) S.mansoni;   c) S.japonicum.

 7. A man has eaten an undercooked beef liver (contained fascioles). Can this person be infected with fascioliasis?

 8. Indicate the system which Cestodes have not:

A    digestive system

B    excretory system

C    nervous system

D    respiratory system

E    genital system

9. What kind of helminthosis is characterised by the development of anemia?

A   Teniasis solium    B    Cysticercosis     C   Taeniasis saginata

D   Diphyllobothriasis                      E    Fascioliasis

10. Which cestode causes cysticercosis?

A    Taenia solium     B    Taenia saginata     C     Diphyllobotrium latum

11. What is the characteristic feature of gravid proglottid of Taenia solium?

A   17 –35 uterine branches

B   7 –12 uterine branches

C   bilobed ovary

D   trilobed ovary

E   gravid uterus is in the form of rosette

Correct answers of test evaluations and situational tasks:

1. C.        2. B.       3. A.        4. A, D.         5. Children can not be infected with fascioliasis, because infective stage for humans is metacercarie (in fish).   6. a) veins of bladder; b) veins of colon; c) veins of small intestine, liver.   7. This person can not be infected with fascioliasis, because infective stage for humans is metacercarie.   8. A, D.   9. D.   10. A.  11. B.

 

Self-study (1415 - 1500).

Written test students in “MOODLE”, thematic view instructional videos, in-depth study of material fact made in the independent work.

 

References 

Basic:

1. Bihunyak T.V. Medical Biology – Ternopil:TSMU, 2010. – 214 p.

2. Lynn B. Jorde Medical Genetics / Lynn B. Jorde, John C.Carey, Michael J.Bamshad [et al] – 2006. – 363 p.

3. Sylvia S. Mader Biology. / Sylvia S. Mader, Wm. C. Brown Publishers: Dubuque, Lowa – Melbourne, Australia – Oxford, England, IV edition. – 1996. – 850p.

4. Goodman R. Medical cell biology – Philadelphia, Lippincott-Reven, 1998. –

320 p.

5. Lazarev K.V. Medical biology – Simferopol: IAD CSMU, 2002. – 350 p.

6. Stephen L. Wolfe Introduction to Cell and Molecular Biology – Wadsworth Publishing Company, 1995. – 820 p.

7. G. Thomas Strickland Hunter’s Tropical Medicine – W.B. Saunders Company, 1984. – 1057 p.

Additional:

1. Alberts B. Molecular biology of the cell / Alberts B., Bray D., Lewis J. [et al] – Garland Publishing, NY&London, 1997. – 630 p.

2. Jan A. Pechenik Biology of the Invertebrates – Boston, Massachusetts, III-th edition, 1996. – 557 p.

3. Alberts B. Molecular biology of the cell / Alberts B., Bray D., Lewis J. [et al] –- Garland Publishing, NY&London, 1989. – 1218 p.

4. Strachan T. Human molecular genetics / Strachan T., Read A.P. – Bios Scientific Publ., 1996. – 596 p.

5. Sylvia S.Mader Biology. Art notebook / Sylvia S.Mader, Wm. C. Brown Publishers: Dubuque, Lowa – Melbourne, Australia, 1995. – 205 p.

6. USMLE STEP1. Biochemistry. Lecture notes. – 2004. – 351 p.

7. Elmer W. Koneman Color Atlas and Textbook of Dioagnostic Microbiology / Elmer W.Koneman, Stephen D.Allen, William M.Janda – Lippincott, 1997. – 1395p.

 

 

 

 

                                                                                                                             Methodical instruction

has been worked out by: Bihunyak Tatyana  

 

Methodical instruction was discussed and adopted

at the Department sitting 27.08.2013.

Minute № 1