Background

Human beings can get infected by types of nematodes such, as trichuriasis, ascariasis, hookworm, filiarisis, dirofilariasis, enterobiasis, strongyloidiasis, trichinosis, and angiostrongyliasis (rat lungworm disease). The Nematoda phylum or roundworms is the group in the animal kingdom and consists of around 500,000 species. These roundworms have elongated bodies with symmetry and possess an intestinal system along with a large body cavity. 

While many roundworm species live freely in nature, research has shown that 60 species of roundworm can parasitize humans. Infections caused by roundworms are common among helminthic diseases affecting humans. As per a 2005 World Health Organization (WHO) report 0.807 1.221 billion people worldwide suffer from ascariasis, 604 795 million from trichuriasis and 576 740 million, from hookworm infections. 

Epidemiology

Trichuriasis is the parasitic infection found in the United States impacting, around 2.2 million individuals mainly residing in rural areas of the Southeast. Enterobiasis on the other hand is widely spread with 42 million cases reported. Ascariasis affects 4 million people while hookworm infections are less prevalent. In states Strongyloidiasis has a prevalence rate ranging from 0.4% to 4%. Trichinosis ranges from 4% to 20%. Globally Asia sees a rate of nematode infections with Trichuriasis being the most widespread. Ascaris affects around 1 billion individuals while hookworm impacts 550 750 million people. Trichinosis continues to be a concern for health in several Asian nations. Additionally other nematode infections include filariasis, onchocerciasis, anisakiasis and angiostrongyliasis. The mortality and morbidity rates associated with these species vary based on factors such as race, gender and age groups. 

Anatomy

Pathophysiology

The life cycle of roundworms is important in diagnosis because they usually don’t go through their entire life cycle inside the human body. Some species can be passed directly while others need a period in the soil to grow. Clinical illness typically occurs after spending time in an area where parasites are common. Encountering the parasites doesn’t always lead to infection or abnormal findings. Repeated or intense exposure to a multitude of infective stage larvae is necessary for establishment of the disease. Eosinophilia and high levels of Immunoglobulin E (IgE) in the blood are common in roundworm infections. 

Etiology

Parasitic roundworms known as nematodes can infect the tracts of humans. They typically spread through consuming food or water often linked to conditions and poor hygiene habits. Certain types of these worms can also penetrate the skin especially when walking barefoot on soil that is contaminated. Factors such as sanitation, inefficient waste disposal systems, warm and humid climates, cultural traditions and increased exposure to soil or water in agricultural or outdoor settings all contribute to the transmission of these parasites. Children are at risk due, to their systems being less developed. Effective control methods include enhancing sanitation practices, promoting good hygiene habits and educating the public about health measures. 

Genetics

Prognostic Factors

Light-to-moderate nematode infections generally have a favourable prognosis, depending on the infected organ and severity. Ascariasis should be treated due to the risk of adult worm migration. In endemic areas, long-term treatment with diethylcarbamazine and immunomonitoring are crucial for managing complications. Angiostrongyliasis usually resolves without treatment. 

Clinical History

Patients suffering from nematode infections show the following symptoms: 

Lung invasions: 

1. Fever 
2. Cough 
3. Blood-tingles sputum 
4. Rales 
5. Eosinophilia 
6. Asthma 
7. Pulmonary consolidations 
8. Angioneurotic edema 

Intestinal invasion 

1. Constipation 
2. Diarrhea 
3. Pain in abdomen 
4. Colic/ abdominal cramps 

Muscle and other invasion 

1. Fever 
2. Myalgias 
3. Periorbital and facial edema 
4. Edema and spasm 
5. Sweating 
6. Photophobia 
7. Pain upon swallowing 
8. Rashes and formication 
9. Pneumonia 
10. Encephalitis 
11. Nephritis 
12. Weakness or prostration 
13. Conjunctivitis 
14. Neuropathy 
15. Ungual hemorrhages 

Lymphatic filariasis- B. malayi, B. timori, W. bancrofti 

1. Orchitis 
2. Abscesses 
3. Inflammatory signs 
4. Fever 
5. Obstructive signs 
6. Hypereosinophilia 
7. Chyluria 
8. Lymphadenitis 

Loiasis- Loa loa 

1. Claabar swellings 
2. Eosinophilia 
3. Fever 
4. Urticaria 
5. Pruritis 
6. Eye worm 

Onchocerciasis- O.volvulus 

1. Nodules 
2. Dermatitis 
3. Lymphadenitis 
4. Ocular changes- intraocular microfilariae, Sclerosing keratitis, Optic atrophy, Glaucoma, Blindness, Anterior uveitis chorioetinitis 

Dracunculiasis- D.medinensis, Guinea worm disease 

Allergic manifestations 

1. Erythema 
2. Nausea 
3. Giddiness 
4. Pruritus 
5. Syncope 
6. Fever 

Local lesions 

1. Ulceration 
2. Sterile blister 
3. Papule 
4. Abscesses 

Angiostrongyliasis 

1. Neck stiffness 
2. Abnormal sensations in the arms and legs 
3. Nausea 
4. Vomiting 

Physical Examination

1. trichiura infections:

This includes bloody diarrhea, growth retardation, mild anemia, abdominal pain, rectal prolapse, bloody diarrhea. 

1. vermicularis infection:

Symptoms of this kind of infection include appendicitis, ulcerative lesions, chronic salpingitis, vulvovaginitis. 

A.lumbricoides infection 

This condition is commonly seen in children suffering from severe infections. The presentation includes abdominal distension, cramps, acute intestinal obstruction. 

Hookworms 

The primary manifestations of this disease include chronic protein energy malnutrition and iron deficiency anemia. During the worm attachment phase, abdominal pain, diarrhea, weight loss and intestinal mucosa can be seen. 

S.stercoralis infection 

Some individuals report vomiting, loss of weight and nausea with malabsorption. Abdominal pain or burning sensation and epigastric pain occurs related to weight loss, vomiting, and nausea. 

Other tissues and massive larval invasion of lungs can occur with hyperinfection. 

Angiostrongyliasis 

Infection due to Angiostrongylus cantonensis presents vomiting, nausea, headaches, stiff neck similar to bacterial meningitis. This infection usually resolves on its own without treatment but lasts from two to eight weeks. 

Age group

Associated comorbidity

Associated activity

Acuity of presentation

Differential Diagnoses

1. Asthma 
2. Anthrax 
3. Appendicitis 
4. Diverticulitis 
5. Hodgkin lymphoma 
6. Lymphedema 
7. Tuberculosis 
8. Crohn disease 
9. Acute cholecystitis 
10. Lymphogranuloma venereum 
11. Leprosy 

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

Infections due to intestinal nematodes can be managed effectively through a comprehensive approach including accurate diagnosis, appropriate medication, monitoring, and preventive measures. Diagnosis involves examination of stools, serological tests, imaging, and anthelmintic medications. Symptomatic treatment comprises of nutritional support, hydration, and regular follow-ups. Preventive measures include improved sanitation, public health education, and surgical intervention. 

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

Hygienic environment: 

A good sanitation and hygiene prevent the growth of nematodes. Avoid consuming undercooked or raw snails, slugs and fish. Vector control measures should be practised to avoid infection. 

Use of anthelminthic agents

Albendazole: This is used in the treatment of infections due to roundworm, hookworm and pin worm. It reduced the production of ATP in worms leading to the depletion of energy, immobilization, and finally the death of worms. 

Mebendazole: It is indicated in the treatment of infections due to A.lumbricoides, E.vermicularis, N.americanus and A.duodenale etc. The efficacy of this drug differs by various factors such as degree of infection, preexisting diarrhea, GI transit time, and the kind of helminth strains. It leads to the irreversible blockade of the glucose uptake and ultimately death of helminths. 

Ivermectin: This belongs to the class of avermectin. This drug binds with high affinity to the glutamate-gated chloride ion channels in muscle cells and invertebrate nerve. 

Piperazine: This drug acts by paralysing the worm and expels the worms by normal intestinal peristalsis. 

In patients suffering from acute intestinal perforation and obstruction due to ascariasis might require surgical treatments. 

use-of-phases-of-management-in-treating-intestinal-nematodes

Intestinal nematodes are a serious health issue that can be effectively managed through different phases. These include clinical and laboratory diagnosis, treatment, prevention and control, and patient education. Diagnosis includes recognition of symptoms like pain in the abdomen, diarrhea, anemia, loss of weight, while treatment involves administration of anthraquinone therapy and providing nutritional support. Personal hygiene, implementing measures for environmental control, and improving sanitation facilities help to prevent the spread of infection. Public health measures like deworming campaigns, health education, monitoring and surveillance, and re-evaluation to ensure complete eradication of worms. Each phase plays a crucial role in reducing morbidity and preventing transmission of the disease.  

Medication

Future Trends

Media Gallary

References

Intestinal Parasitic Infections in 2023 | Ahmed | Gastroenterology Research (gastrores.org)