Helminths Virology Question And Answers

Helminths Long Question And Answers

Question 1. Describe the life cycle of ankylostoma duodenal. Write a note on pathogenicity and laboratory diagnosis of Ankylostomiasis

The common name of ancylostoma duodenal is the old-world hookworm

Ankylostoma duodunale Life Cycle:

  • Man is the only definitive host
  • It involves following the steps

Helminths Ankylostoma duodunale Life Cycle

Read And Learn More: Microbiology Question and Answers

Helminths Life cycle of Hookworm

Ankylostomiasis Pathogenicity:

  • Migrating larvae may cause three types of lesions as follows

Helminths Migranting larvae may cause three type of lesions

  • The worm causes hookworm disease in man

Ankylostomiasis’s Clinical features are:

  • Microcytic, hypochromic anemia
  • Epigastric pain
  • Dyspepsia
  • Vomiting
  • Diarrhea

Ankylostomiasis Laboratory Diagnosis:

1. Direct methods:

Helminths Direct method

2. Indirect methods:

Helminths Indirect method

Question 2. Enumerate the common tapeworms. Describe the morphology, life cycle, and laboratory diagnosis of taeniasolium


  • Taenia saginata
  • Taeniasolium
  • Echinococcus granulosus

Taenia Solium Morphology:

Helminths Taenia Solium Morphology


Taenia Solium Life Cycle:

  • The worm passes its life cycle in two hosts: the definitive host, man, and an intermediate host, pig
  • The adult worm lives in the small intestine of man
  • Eggs are passed out with the feces
  • The animal swallows these eggs and gets infected
  • Oncosphere hatches out
  • It penetrates the gut wall
  • Carried in the systemic circulation
  • The naked Oncospheres are transformed into cysticercus cellulose in the muscle
  • By intake of uncooked or partially cooked pork, enters into the alimentary canal of man
  • The scolex of cysticercus evaginates and attaches to the gut wall
  • It develops into an adult worm

Helminths Life cycle of Taenia Sp.

Taenia Solium Laboratory Diagnosis

1. Stool examination

  • It detects eggs of T. solium

Diagnosis of cysticercosis

2. Diagnosis of cysticercosis

  • It is done by
    • Biopsy examination of subcutaneous nodules
    • X-ray of skull and soft tissues
    • CT scan of the brain
    • Eosinophilia

Helminths Virology Question And Answers

Question 3. Describe the morphology, life cycle, and pathogenesis of the Wuchereria branchfti. Discuss the diagnosis of filariasis.

Wuchereria Branchfti Morphology:

1. Adult worms

  • They are transparent, long hair-like structures
  • Color-Creamy white
  • Shape- Filiform with tapering ends

Helminths Wuchereria branchfti Morphology in Adult WormsHelminths Wuchereria branchfti Morphology in Adult Worms

  • Both remain coiled together
  • Life span- 5-10 years

2. Embryos

  • Color- colorless
  • It is transparent
  • Heads and tails- Heads are blunt while tails are pointed
  • Size- 290 micrometer * 6-7 micrometer
  • Covered by hyaline sheath
  • Nuclei appear as granules

Helminths Microfilaria of Wuchereria boncrofti

Wuchereria Branchfti Life Cycle:

  • Wuchereria bancrofti passes its life cycle in man and mosquito
  • Adult worms are present in the lymphatics system of man
  • Male fertilises female
  • Embryos or microfilariae are discharges
  • These reach bloodstream
  • Microfilariae are taken up by mosquitoes during a blood meal
  • It develops in mosquito
  • Through the bite of mosquito, the infective larvae are deposited on the skin
  • This penetrates the skin and reaches the lymphatic channels
  • Gets settled in lymph nodes
  • Develops into an adult worm
  • Again fertilization occurs and the cycle is repeated

Helminths Life cycle of Wuchereria Bancrofti

Wuchereria Branchfti Pathogenesis:

  • W. bancrofti causes filariasis

Wuchereria Branchfti Types:

Helminths Wuchereria branchfti Types

Diagnosis Of Filariasis:

1. Direct methods

  • Samples collected are
    • Blood
    • Chylous urine
    • Exudate of lymph varix
    • Hydrocele fluid
  • Blood film should be made in night between 10 pm to 2 am as the number of microfilariae is more at night

2. Indirect methods

  • It includes
  • Blood examination- Detects Eosinophilia
  • Serological tests like ELISA, indirect fluorescent antibody, and indirect haemagglutination assay.

Helminths Short Question And Answers

Question 1. Hydatid cyst:

  • The cyst wall secreted by the embryo
  • It consists of the following.
  1. Ectocyst
  2. Endocyst

1. Ectocyst:

  • It is a hyaline membrane which form thick, tough outer circular layer and is elastic in nature.
    • When incised it curls on itself
  • As a result, it exposes the inner layer

2. Endocyst:

  • It is inner (or) germinal layer
  • It forms an ectocyst on outer side
  • It gives rise to brood capsules and scolices on inner side.

Hydatid fluid:

  • It is secreted by endocyst.

Hydatid cyst Characteristics:

  • It is clear, colourless (or) pale yellow fluid.
  • It is a slightly acidic nature
  • It is highly toxic, when absorbed it gives rise to anaphylactic symptoms.
  • Due to its antigenic nature it is used for Casoni’s test.
  • It has a low specific gravity
  • Composition- It contains
    • Sodium chloride
    • Sodium sulfate
    • Sodium phosphate
    • Sodium and calcium salts of succinic acid

Hydatid sand:

  • It is a granular deposit which consists of brood capsules, free scolices, and loose hooklets.
  • It gets settled at the bottom of the hydatid cyst

Question 2. cassoni’s test

It is an immediate hypersensitivity skin test introduced by Casoni in 1911.

Cassoni’s test Method:

  • Sterile hydatid fluid is used as an antigen.
  • Hydatid fluid is obtained from hydatid cyst from humans or animals
  • It is made of sterile
  • Now 0.2 ml of it is injected intradermally in one arm
  • While 0.2 ml of normal saline is injected intradermally in the other arm

Cassoni’s test Result:

  • It produces a large wheal measuring 5 cm in diameter or more within 30 minutes in all positive cases.
  • Also shows multiple pseudopodia.

Question 3. Microfilaria

  • Microfilariae are the larvae of nematodes.
  • The female nematodes are viviparous giving birth to larvae called microfilariae.
  • It needs two hosts to complete its life cycle man and a blood-sucking insect

Microfilaria Features:

Helminths Microfilaria Features

Question 5. Cysticercus Ceilulosae

  • Cysticercus cellulose is the larval stage of taenia solium
  • It develops in the muscles of the pig which is an intermediate host
  • A mature cyst is an opalescent ellipsoidal body and the long axis of the cyst is parallel to the muscle fiber.
  • A dense milky white spot is present at the side where the scolex with its hooks and suckers remains invaginated.
  • The cyst develops further when ingested by man which is the definitive host
  • It may develop in any organ but are usually present in the subcutaneous tissues and muscles.

Various features of cysticercosis.

  • They cause palpable nodule in sub-cutaneous tissues and muscles
  • In the brain leads to epileptic attacks.
  • Neurocysticercosis involving the nervous system is the most serious form

Question 6. Diagram of Fertilised egg of ascaris lumbricoides

Helminths Eggs of Ascaris lumbricoides

Question 7. Life cycle of Ascaris lumbricoides

  • Ascaris lumbricoides passes its life cycle in only one host i.e. Man
  • Adult worms reside in the jejunum of man
  • The passing of Fertilised eggs containing the unsegmented ovale in the feces
  • These develop in soil
  • Rhabditiform larva develops from the unsegmented ovum
  • This undergoes first molting
  • Intake of food, drink or raw vegetables contaminated with eggs containing Rhabditiform larvae causes infection in man
  • Liberation of Rhabditiform larvae occurs in the upper part of the small intestine
  • They burrow through the mucous membrane of the small intestine
  • It is carried to the liver and then enter pulmonary circulation
  • They reach lungs and enlarge
  • They break through the capillary wall and reach alveoli
  • The larvae reach the bronchi, then the trachea and are swallowed after reaching the pharynx
  • Pass down to esophagus, stomach and then gets localized in the upper part of the small intestine
  • Here another molting occurs and the larvae grow into an adult worm
  • Thus the cycle repeats

Helminths Life cycle of Roundworm

Question 8. Larva migrans

It is a condition caused by ingestion of embryonated eggs of some nematodes parasitizing animals

Larva migrans Pathogenesis:

  • Larvae are hatched in the small intestine
  • These reach extraintestinal sites
  • Gets settled in the liver, lungs, and other organs
  • This leads to the formation of granulomatous lesions

Larva migrans Clinical Features:

  • Leucocytosis
  • Eosinophilia

Larva migrans Diagnosis:

  • Serological tests detect antibodies in serum

Larva migrans Prevention:

  • Deworming animals prevent this disease

Question 9. Name four tapeworms.

  • Taeniasolium
  • Taeniasaginata
  • Echinococcusgranulosus
  • Diphyllobothrium latum
  • Hymenolepsis nana

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