CLASSIFICATION OF ASCARIS LUMBRICOIDES
It is one of the most common nematodes found in all parts of the world especially in India, China, Philippines, Korea and Pacific Islands.
HABIT AND HABITAT
Ascaris lumbricoides is found in the intestine of man and the pig. Both forms are morphologically identical having two different physiological strains. The infective eggs from man’s Ascaris will not develop into the pig and similarly infective eggs obtained from the pig Ascaris will not develop into the man. However, the two specimens are called as Ascaris lumbricoides variety A. humanis (found in man) and A. lumbricoides (suum found in pig).
GENERAL CHARACTERSTICS OF ASCARIS LUMBRICOIDES
- Commonly known as Round worm. It causes ascariasis in man especially in children. Infection occurs by eating raw and uncooked vegetables.
- Shows sexual dimorphism with separate male and female individuals. Males measure 15 to 30 cm in length and female 20 to 35 cm.
- Tail end of male is ventrally curved containing cloacal aperture, through which two equal isospicules project.
- Tail end of female is bluntly pointed. Female genital opening or vulva found in anterior one third region.
- Anterior ends exhibit same structures in both male and female.
- Mouth is situated at the anterior extremity which is guarded by one dorsal and two sub-ventral lips.
- Amphids are found in the sub-ventral lips.
- Body is elongated and cylindrical.
- Two lateral, one mid-dorsal and one mid-ventral longitudinal chords extent from anterior to posterior end. Excretory pore lies at a distance of about 2 rom from anterior end.
- No intermediate host in life history.
Pathogenic nematode parasite causing haemorrhage, haemoptysis, appendicitis, peritonitis, tumour, ulcer, diarrhoea, eosinophilia and death. Its infection can be avoided by not eating raw and uncooked vegetables especially grown on human night soil fertilizer. Ascaris infection also causes disturbances in the nucleic acid, sugar, protein and fat metabolism of the host. Sometimes intestinal human is blocked by several parasites.
Prevention : Avoid eating raw unwashed and inadequately cooked vegetables and food. Contaminated water should not be taken.
The animal has unsegmented cylindrical body, curved tail in male, pointed tail in female and hence it is A. lumbricoides.