Parasitology 1 respiratory

What is a focal lung lesion?

A lesion restricted to a specific area of the lung.

Which parasites cause cystic lung lesions?

Echinococcus granulosus (hydatid disease).

Which parasite causes lung abscess?

Entamoeba histolytica.

Which parasite causes consolidation and pleural effusion in lungs?

Paragonimus westermani.

Which parasite causes coin lesions in the lung?

Dirofilaria immitis.

What is the geographical distribution of Echinococcus granulosus?

Cosmopolitan.

What is the length of the adult Echinococcus granulosus worm?

About 5 mm.

What is special about the larval stage of Echinococcus granulosus?

It is the largest larval stage of all tapeworms.

Who is the definitive host of Echinococcus granulosus?

Dog.

Where does the adult Echinococcus granulosus reside?

Small intestine of dogs.

What is the life cycle sequence of Echinococcus granulosus?

Egg → hydatid cyst larva in man → adult worm in dog.

What is hydatid disease?

A pathological condition caused by the hydatid cyst in human tissues.

Which organ is most commonly affected by hydatid disease?

Liver (70%).

What is the second most common organ affected by hydatid disease?

Lung (20%).

What is the usual size of a hydatid cyst?

1–10 cm.

What is the shape of a hydatid cyst?

Spherical.

What is the pericyst?

Fibrous capsule produced by the host around the cyst.

How many layers form the wall of a hydatid cyst?

Two layers.

What are the layers of the hydatid cyst wall?

Outer laminated layer and inner germinal layer.

What does the germinal layer produce?

Scolices, brood capsules, and daughter cysts.

What are brood capsules?

Structures formed from germinal layer containing scolices.

What are daughter cysts?

Cysts formed of the same two layers as the mother cyst.

What is hydatid fluid?

Antigenic and highly toxic fluid inside the cyst.

What is hydatid sand?

Detached scolices, brood capsules, and daughter cysts in hydatid fluid.

How is hydatid disease transmitted to humans?

Ingestion of eggs.

How can humans acquire hydatid infection directly?

Contact with infected dogs.

How can hydatid disease be transmitted indirectly?

Contaminated food or drinks and flies.

What type of disease is hydatid disease?

Zoonotic disease.

What are symptoms of pulmonary hydatidosis?

Dyspnea, cough, chest pain, hemoptysis.

What is the danger of hydatid cyst rupture?

Anaphylactic shock and secondary cyst formation.

What clinical factors suggest hydatidosis in endemic areas?

Slowly growing cyst and history of dog contact.

Why is diagnostic aspiration of hydatid cyst dangerous?

It may cause leakage and anaphylactic shock.

How can scolices be demonstrated in hydatid disease?

In sputum using Ziehl–Neelsen stain.

What radiological sign is characteristic of pulmonary hydatid cyst?

Lily pad (water-lily) sign.

What blood finding may be present in hydatid disease?

Eosinophilia.

What is the Casoni test?

Intradermal allergic test for hydatid disease.

Which serological tests diagnose hydatid disease?

ELISA, IHA, and IFA.

What is the main treatment of hydatid disease?

Surgery.

Which drug is given preoperatively for hydatid disease?

Mebendazole.

What is PAIR technique?

Percutaneous aspiration, injection, and reaspiration.

When is PAIR technique used?

When surgery is impossible.

What substance is injected during PAIR technique?

10% formalin or ethanol.

What preventive measures reduce hydatid disease?

Hand hygiene, dog deworming, and controlling stray dogs.

What is the geographical distribution of Entamoeba histolytica?

Cosmopolitan.

What is the habitat of Entamoeba histolytica in humans?

Caecum and sigmoid-rectal region.

What is the infective stage of Entamoeba histolytica?

Quadrinucleated cyst.

How is Entamoeba histolytica transmitted?

Feco-oral route.

What foods commonly transmit Entamoeba histolytica?

Contaminated raw vegetables and water.

What is the size of Entamoeba histolytica trophozoite?

10–60 µm.

What are the cytoplasmic components of the trophozoite?

Ectoplasm and endoplasm.

What does the endoplasm contain?

Nucleus, food vacuoles, bacteria, leukocytes, and RBCs.

How many nuclei are present in the mature cyst?

Four nuclei.

How does pulmonary amoebiasis usually develop?

Rupture of liver abscess through diaphragm.

Which lung lobes are commonly affected in amoebic lung abscess?

Right lower and middle lobes.

What sputum appearance is characteristic of amoebic lung abscess?

Reddish-brown “anchovy sauce” sputum.

How is intestinal amoebiasis diagnosed?

Stool examination for trophozoites or cysts.

How is pulmonary amoebiasis diagnosed?

Aspirate examination and serology.

Which drugs treat amoebiasis?

Metronidazole and Tinidazole.

Which luminal amoebicide is added for eradication?

Paromomycin.

What is the geographical distribution of Paragonimus westermani?

Southeast Asia, Africa, Central and South America.

Where do adult Paragonimus worms live?

In lung pockets.

What is the infective stage of Paragonimus westermani?

Encysted metacercaria.

How do humans acquire Paragonimus infection?

Eating raw or undercooked crabs or crayfish.

What pulmonary symptoms are caused by Paragonimus?

Cough, hemoptysis, pleural effusion.

What lab finding is common in paragonimiasis?

Eosinophilia.

How is paragonimiasis diagnosed?

Eggs in sputum or feces and imaging.

What is the treatment of paragonimiasis?

Praziquantel.

What is Dirofilaria immitis?

Dog heartworm causing pulmonary dirofilariasis.

How is Dirofilaria transmitted to humans?

Mosquito bites.

Who is the definitive host of Dirofilaria immitis?

Dogs.

Where do adult Dirofilaria worms reside?

Pulmonary arteries and heart.

What type of host is humans in dirofilariasis?

Accidental dead-end host.

Why do humans not transmit dirofilariasis?

No microfilariae are produced.

What radiological finding is typical of pulmonary dirofilariasis?

Coin lesion.

How is pulmonary dirofilariasis diagnosed?

Chest X-ray and biopsy.

What is the definitive treatment of pulmonary dirofilariasis?

Surgical removal.

How can dirofilariasis be prevented?

Avoid mosquito bites and treat animal reservoirs.