Ascariasis (as-kuh-RIE-uh-sis) is an infection of the small intestine caused by Ascaris lumbricoides, a species of parasitic roundworm. These worms use the human body as a host to mature from microscopic larvae into adult worms. Surprisingly, adult worms can grow to be more than a foot (30 centimeters) long.
It is one of the most common human worm infections worldwide, particularly prevalent in tropical and subtropical regions where sanitation is poor and clean water is scarce. While mild cases often present with no symptoms at all, heavy infestations can cause serious, life-threatening complications in the lungs and intestines.
Symptoms
Symptoms vary drastically depending on which part of the body the worms are currently inhabiting during their life cycle (the Lungs or the Intestines).
1. In the Lungs
After microscopic eggs are ingested, they hatch into larvae in the intestines and then migrate through the bloodstream or lymphatic system to the lungs. During this stage (which lasts 6 to 10 days), you may experience respiratory symptoms similar to asthma or pneumonia:
- Persistent, dry cough.
- Shortness of breath.
- Audible wheezing.
2. In the Intestines
The larvae eventually travel up the airways to the throat, where they are swallowed back down into the stomach, finally returning to the small intestine to mature into adults. Mild cases may cause vague abdominal discomfort, but heavy infestations cause:
- Severe, intermittent abdominal pain.
- Nausea and vomiting.
- Diarrhea or bloody stools.
- Unexplained fatigue and weight loss.
- Visible worms in vomit or passed in the stool.
When to Seek Emergency Care
Consult your doctor immediately if you have persistent abdominal pain, chronic diarrhea, or unexplained nausea. Seek emergency medical care immediately if you vomit up a worm, pass a worm in your stool, or experience sudden, excruciating abdominal pain, which could indicate a bowel obstruction.
Causes & Life Cycle
Ascariasis is not spread directly from person to person through casual contact. It is strictly caused by ingesting soil mixed with human feces containing worm eggs, or eating unwashed, raw food grown in contaminated soil.
[Image of the life cycle of Ascaris lumbricoides in the human body]- Ingestion: You accidentally eat microscopic eggs present in contaminated soil, water, or unwashed produce.
- Migration: Eggs hatch into larvae in the intestine, penetrate the intestinal wall, and travel via the bloodstream to the lungs.
- Maturation: After spending about a week in the lungs, the larvae break into the airway, travel up the throat, are coughed up, and swallowed back down into the digestive tract.
- Reproduction: Back in the intestines, they grow into mature male and female worms. A single female can lay up to 200,000 eggs a day, which leave your body through feces, starting the cycle over again.
Risk Factors
- Age: It is overwhelmingly most common in children 10 years old or younger (as they frequently play in dirt and put unwashed hands in their mouths).
- Climate: Prevalent in warm, humid, tropical, or subtropical regions where eggs can survive in the soil for years.
- Sanitation: Highly common in developing areas where human feces are used as agricultural fertilizer or where modern sanitation infrastructure is poor.
Complications
Mild cases usually resolve without major long-term issues, but heavy, untreated infestations can lead to:
- Nutritional Deficiencies: A large mass of worms steals vital nutrients from the host, leading to loss of appetite, anemia, and stunted physical growth in children.
- Intestinal Blockage: A large, tangled mass of adult worms can physically block the intestine, causing severe cramping, vomiting, and a life-threatening bowel perforation.
- Duct Blockages: Wandering worms can occasionally block the narrow ducts of the liver, gallbladder, or pancreas, causing severe, acute pain.
Diagnosis
Doctors may use the following clinical methods to confirm an active infection:
- Stool Tests: To look for microscopic eggs and larvae under a microscope. (Note: Eggs typically do not appear in the stool until about 40 days after the initial infection).
- Blood Tests: To check for a highly elevated number of specific white blood cells called eosinophils, which indicate a parasitic infection.
- Imaging (X-ray/Ultrasound): A large mass of adult worms may be visible in abdominal X-rays or ultrasounds. Chest X-rays can sometimes reveal larvae migrating through the lungs.
Treatment
Infections with absolutely no symptoms may not always require treatment, but symptomatic cases require targeted medication to clear the parasite.
1. Medications
Prescription anti-parasite medications are the standard first line of defense. They work by paralyzing or killing the adult worms so they can be passed in the stool:
- Albendazole (Albenza)
- Ivermectin (Stromectol)
- Mebendazole
2. Surgery
In severe cases, surgical intervention may be required to physically remove a mass of worms causing a total intestinal obstruction, bowel perforation, or appendicitis.
Prevention & Lifestyle
The single best defense against Ascariasis is strict hygiene and common-sense food safety:
- Wash Hands: Always wash hands thoroughly with soap and warm water before eating, before preparing food, and immediately after using the toilet or changing a diaper.
- Wash Produce: Thoroughly wash, peel, and cook all raw fruits and vegetables, especially those grown in regions lacking modern sanitation.
- Avoid Soil: Teach children not to put their hands in their mouths after playing outdoors in the dirt.
- Water Safety: Drink only sealed, bottled water or heavily boiled water when traveling to developing countries.
Frequently Asked Questions (FAQs)
Can I catch Ascariasis from my dog or cat?
No. While pets frequently get their own types of roundworms (like Toxocara canis in dogs), the specific roundworm that causes Ascariasis (Ascaris lumbricoides) is uniquely adapted to humans. You cannot catch this specific infection from your pet.
How long can a roundworm live inside my body?
If left untreated, an adult Ascaris worm can live inside the human small intestine for 1 to 2 years. Because they do not multiply inside the body (the eggs must be passed into the soil to become infectious), the infection will eventually clear itself if you are not re-exposed to contaminated soil.
References
- Centers for Disease Control and Prevention (CDC) - Ascariasis
- World Health Organization (WHO) - Soil-transmitted helminth infections
- Mayo Clinic - Ascariasis Symptoms and Causes
Reviewed & Sources: WHO, CDC, medical textbooks
Last Updated:
No comments:
Post a Comment