In this article we will discuss about the pathogenicity, prevention and treatment of Ascariasis disease caused by ascaris (Roundworm).
The disease which is caused by Ascaris in man is known as Ascariasis. Man gets infection by consuming food and water contaminated with infective eggs. Ascaris is an important parasite of man which often occurs in high levels in population living under conditions of poor hygiene. Ascariasis is relatively rare in urban communities of most highly developed countries. Ascaris lumbricoides is more common in children than in adults.
It has been estimated that there are about 1000 million cases of Ascariasis worldwide, with average prevalances in the range of 32-60%. The infection rate was as high as 90% in some surveys of the children between the ages of 6 and 12 years.
The infection results in malnutrition and retardation of growth in children. Large number of Ascaris cause abdominal discomforts, colic pains and interfere with the digestion of man. The other symptoms associated with both the larval and adult stages of Ascaris are pneumonitis, asthma, diarrhoea, nausea, abdominal pain, anorexia etc.
Pathogenicity of Ascariasis:
The disease caused by Ascaris is commonly called Ascariasis.
The symptoms attributed to Ascaris infection may be divided into two groups:
(a) Those produced by the larval stages and
(b) Those produced by the adult worms.
(a) Symptoms due to migratory larvae:
i. Larvae in the lungs produce pneumonia with fever, cough, dyspnoea. Sputum which is often blood-tinged may contain Ascaris larvae. Urticarial rash and eosinophilia (20 percent) are seen in such cases.
ii. As a result of penetration of intestinal wall of man by the newly hatched larvae, haemorrhage, inflammation of intestinal wall, fever may occur to man.
iii. Larval stages of this parasite may be carried to different organs through general circulation and damages organs such as brain, spinal cord, kidneys etc. and may cause unusual symptoms.
(b) Symptoms due to the adult worms:
i. Adult Ascaris may cause vitamin A deficiency, malnutrition, nausea etc.
ii. Adult worms are residing inside the lumen of the intestine of man and damaging the inner lining of intestine and cause peritonitis.
iii. Wandering Ascaris may enter the lumen of vermiform appendix causing appendicitis.
iv. Obstructive jaundice and acute haemorrhagic pancreatitis have been known to occur when the worm has entered into the biliary passage. At time the parasite penetrates high up in the liver causing one or more abscesses.
v. Sometimes the worms cause general nervousness and convulsions.
vi. More than thousands of adult worms may be present in a single host where they cause abdominal discomforts along with vomiting.
Prevention of of Ascariasis:
i. Good sanitation and a safe water supply prevent the infection of the parasite.
ii. Green vegetables are to be cleaned properly before ingestion as food.
iii. Hands should be properly washed before eating food stuff.
iv. Education of children in school should be arranged on sanitary laws and hygiene.
The obvious basic control strategy is to interrupt transmission of infective eggs to water, food or human hands.
Treatment of Ascariasis:
i. Drugs in general use for treatment of Ascariasis are antihelminthic drugs, viz. — lavamisole, pyrantel, mebendazole and albendazole.
ii. Infection of Ascaris can be treated with a dose of hexylresorcinol crystals in gelatin capsule after about 12 hours fasting. The dose, followed by a fast of another 4 hours, kills the worms, which can be finally expelled by a purgative like sodium sulphate.
iii. According to Ottesen (1990), ivermectin drug has been shown to be 100 per cent effective against Ascariasis.