Write down the life cycle of Ascaris lumbricoides Round Worm

 Life cycle of Ascaris lumbricoides  Round Worm :
*Infective Agent : Embryonated Egg
*Infective From :Rhabditiform larva
*Mode of infection :ingestion of contaminated foods or drink
*Portal of Entry : Alimentary canal
*Migration : Through lungs
*Site Of Location :small intestine

 Life Cycle :
a)Host -Man is the only known definitive host
b)Stages-The various stages in the life cycle are described below

Stage 1.Egg in Faceces 
Fertilized egg containing the unsegmented ovum are passed with the faeces

Stage 2.Development in soil :
A  rhabditiform larva is developed from the unsegmented ovum within the egg shell which is ineffective to  host .Before hatching the larva undergoes a molting

Stage 3.Infection by ingestion of larva :

When infected with food & drink or raw vegetables ,the embryonated egg pass down to duodenum & rhabditiform larva are liberated in the upper part of small intestine

Stage: Migration through the lungs :
The newly hatched larva burrow this way through the mucous membrane of small intestine & are carried by the portal circulation to the liver--->right heart --> pulmonary circulation --->double molting -->lung alveoli

Stage 5.Re-entry into stomach &the small intestine 
From lung alveoli-->bronchi -->Trachea -->larynx-->swallowed -->stomach -->upper intestine

Stage 6.Sexual maturity & egg liberation
Larva grow into adult -->sexually mature-->Gravid female --> Discharge egg in stool -->

Cycle is completed & fresh cycle starts        
                                                                               
                                                                      ( k.M.C)