Diseases Caused by Nematodes (In Humans, Animals and Plants): Infection

Understanding Nematodes

Nematodes are long roundworms belonging to the family Nematoda. They are bilaterally symmetrical, undamaged, and covered with a thick cuticle. Just like Plasmodium life cycle causes malaria, nematodes also have life cycles that spread disease. Nematodes release antigens that are recognized by the immune system.

General characteristics and appearance:

• The nematode has a complete digestive tract, including mouth, intestine, and rectum.

• Their body structure is simple, with the pseudo-coelom acting as a body cavity.

• Reproduction: sexually and asexually.

Nematodes Classification

Nematodes are roundworms found in many environments. They play different roles in health and diseases. Based on their behavior, nematodes are classified into two types: parasitic nematodes and free-living nematodes.

1. Parasitic nematodes: It affects plants, animals, and humans, where it brings out different diseases.

2. Living nematodes: These are, found in the soil, in freshwater, and the sea and are useful to the ecosystem.

Major Nematode Diseases in Humans

Nematode diseases are caused by parasitic roundworms. They infect millions of people, especially in poor hygiene areas. These diseases spread through contaminated food, water, or soil. Common nematode infections include ascariasis, filariasis, hookworm, and others.

Ascariasis

• Causative Agent: Ascaris lumbricoides

• Ascaris Life Cycle: Eggs are ingested through contaminated food or water. Larvae hatch within the gut, migrate to the lungs, and then go lower back to the gut to mature into grownup worms.

• Mode of Transmission: Consumption of eggs from an infected food, water, or soil source.

• Symptoms and Complications: It also causes; abdominal pain, malnutrition, intestinal blockage, and retardation in children's growth.

• Diagnosis and Treatment: By using the stool examination; the treatment is by giving the antiparasitic drugs inclusive of albendazole, or mebendazole.

• Prevention Strategies: Better hygiene practices such as the availability and use of iodized salt, clean water, sanitation, and hygiene, deworming.

Filariasis

• Causative Agents: Wuchereria bancrofti, Brugia malayi, and Brugia timori

• Life cycle: Caused by mosquito bites. The worms enter the bloodstream and develop into adult worms in the capillaries, causing blockage.

• Mode of infection: Bites of infected mosquitoes.

• Symptoms and complications: lymphedema, gastritis, and severe swelling of limbs and organs.

• Diagnosis and treatment: Diagnosis done by blood test method; Treatment with antibiotics.

• Preventive measures: mosquito control measures, usage of bed nets, and mass vaccination.

Trichuriasis

• Causative Agent: Trichuris trichiura (whipworm)

• Life Cycle: Eggs are swallowed and hatch in the small intestine. Larvae migrate into the large intestine, develop, and anchor themselves on the mucosa.

• Transmission: Drinking water or consuming food or soil that has the eggs of the organism.

• Symptoms and Problems: It also has a short-term side like diarrhea, stomach ache, deficiency in iron, and bleeding at times after a long period only.

• Diagnosis and Cure: Looking for eggs through a stool examination; Medicines are used to treat it including mebendazole or albendazole.

• Prevention: Better hygiene practices, practices, and talks on hygiene and administration of anti-worm compounds.

Hookworm Infection

• Causative Agents: Ancylostoma duodenale and Necator americanus

• Life Cycle: Larvae invade the skin, migrate through the bloodstream to the lungs, and are then swallowed to reach the intestine.

• Mode of Transmission: Skin's contact with infected soil.

• Symptoms and Complications: Anaemia, malnutrition, stomach pain, and fatigue.

• Diagnosis and Treatment: Diagnosis is done by stool exam; treated with antiparasitic pills, including albendazole or mebendazole.

• Prevention Strategies: Wearing shoes, progressing sanitation, and health schooling.

Enterobiasis (Pinworm Infection)

• Causative Agent: Enterobius vermicularis

• Life Cycle: Eggs are laid, hatch in the small intestine, and grow in the colon. Females lay their eggs around their spines at night.

• Mode of infection: Egg ingestion from contaminated alcohol, surfaces, or food.

• Symptoms and complications: perianal itching, irritability, sleep problems.

• Diagnosis and treatment: diagnosis by “tape test”; Drugs such as mebendazole or albendazole.

• Preventive measures: good hygiene, regular hand washing and bed sheets, and treatment of all household members.

Strongyloidiasis

• Causative Agent: Strongyloides stercoralis

• Life cycle: Worms penetrate the skin, enter the bloodstream, migrate to the lungs, and then are ingested to mature in the intestinal tract.

• Mode of infection: skin contact with contaminated soil.

• Symptoms and complications: Abdominal pain, nausea, skin rashes, and hyperinfection syndrome that can be life-threatening in immunocompromised individuals.

• Diagnosis and treatment: diagnosis by stool test or serological test; Ivermectin or albendazole.

• Preventive measures: improved hygiene, wearing shoes, and health education.

Table: Common Nematode Infections in Humans

Nematode infections are part of major human health and diseases. These are caused by parasitic roundworms. Common nematode diseases include ascariasis, hookworm infection, and filariasis. They spread through soil, contaminated food, or insect bites.

Clinical Implications and Symptoms of Nematode Infections

Nematode infections can cause serious complications such as malnutrition, stunted growth, and organ damage in chronic diseases, including gastrointestinal problems, anemia, skin rashes, and respiratory issues. Like protozoan disease, nematode infections affect humans and animals internally.

Long-term health effects: The long-term health consequences of nematode infections include chronic anemia, childhood renal disease, and irreversible lymphatic damage in filariasis. Innate immunity is the first line of defense against nematode invasion. Early diagnosis and treatment are essential to prevent these complications.

Importance of early diagnosis and treatment: By adopting these recommendations, the health risks that are faced by such affected people can be diminished and their lives improved while at the same time help prevent the extension of such diseases in the concerned community.The difference between innate and adaptive immunity matters in nematode infection response.

Prevention and Control of Nematode Infections

Hygiene and Hygiene Practices: Thus, transmission of nematode diseases can be controlled based on the practices like hand washing, proper discharge of human wastes among others.

Public health policies and campaigns: Reducing the level of awareness on health hence embracing education, better hygienic practices and accessibility to safe water is crucial in managing nematode diseases.

Role of drugs and prevention strategies: MDA programs in which antibiotics are administered to at-risk groups can actually combat nematode diseases.

Importance of community awareness and education: Educating communities about nematode disease transmission, symptoms, and prevention can enable individuals to develop prevention strategies and seek treatment.

MCQs on Nematode Infections

Question: Out of the following diseases which one is caused by a nematode parasite?

1. Poliomyelitis

2. Amoebiasis

3. Filariasis

4. Leprosy

Answer: Filariasis, also called elephantiasis, is a nematode disease caused by the transmission of Wuchereria bancrofti. The mode of infection is through the bites of infected female Culex mosquitoes and targets the lymphatic system. Adult worms cause inflammation and damage to the lymphatic vessels with the resultant severe swelling of especially limbs and genitals. Symptoms may only appear years after infection, resulting in significant disabilities and social stigma among affected people.

Hence, the correct answer is Option (3) Filariasis.

Question: An intestinal parasite which causes blockage of the intestinal passage and whose eggs are excreted along with the faeces of infected person is ________.

1. Wuchereria bancrofti

2. Ascaris

3. Epidermophyton

4. Microsporum

Answer: The eggs of the parasite are excreted along with the feces of infected persons which contaminate soil, water, plants, etc

A healthy person acquires this infection through contaminated water, vegetables, fruits, etc.

Hence, the correct option is 2) Ascaris.

Question: Assertion: Diseases caused by nematodes are parasitic infections that can affect humans.

Reasoning: Nematodes are a type of roundworm that can infect humans and cause diseases by invading and damaging host tissues.

1. Both Assertion (A) and Reason (R) are the true and Reason (R) is a correct explanation of Assertion (A).

2. Both Assertion (A) and Reason (R) are the true but Reason (R) is not a correct explanation of Assertion (A).

3. Assertion (A) is true and Reason (R) is false.

4. Assertion (A) is false and Reason (R) is true.

Answer: Diseases caused by nematodes are parasitic infections that can affect humans and cause a range of illnesses. These parasitic worms can be found in contaminated soil or water or can be transmitted from person to person through contact with infected bodily fluids or contaminated objects. When nematodes enter the body, they can invade and damage host tissues, leading to the development of symptoms.

For example, the nematode parasite Wuchereria bancrofti is the cause of lymphatic filariasis, a disease that can lead to painful swelling of the limbs and genitals. Lymphatic filariasis is transmitted through the bites of infected mosquitoes, which inject the nematode larvae into the bloodstream of the human host. Once inside the body, the nematodes migrate to the lymphatic system, where they can cause inflammation and damage, leading to the development of symptoms.

Therefore, it is important to take appropriate measures to prevent and treat nematode infections, including avoiding exposure to contaminated soil or water, using insect repellent, and seeking appropriate medical care if symptoms develop. Additionally, some medications can be used to treat nematode infections, but they may have side effects and require careful monitoring by a healthcare professional.

Hence, the correct answer is Option (1) Both Assertion (A) and Reason (R) are true and Reason (R) is a correct explanation of Assertion (A).

Also Read:

• Disease caused by Nematodes MCQs

• Immunology
• Cancer