1. Ascariasis is caused by the roundworm Ascaris lumbricoides and is one of the most common helminth infections worldwide, affecting around 1 billion people. 2. Symptoms can include coughing, wheezing and abdominal pain as the worms migrate through the lungs and intestines. Complications can arise if worms cause blockages. 3. Diagnosis is made by examining stool samples under a microscope for Ascaris eggs. Treatment involves oral medications such as albendazole or mebendazole.

1. HELMINTHS Sorokhan V.D., MD., PhD.

2. Ascariasis Introduction Ascariasis is the most common helminthic infection, with an estimated worldwide prevalence of 25% (0.8-1.22 billion people). Pathophysiology Adult A lumbricoides are white or yellow and 15-35 cm long. They live 10-24 months in the jejunum and middle ileum of the intestine. Each day, female A lumbricoides produce 240,000 eggs, which are fertilized by nearby male worms. Eggs may remain viable in soil for up to 17 months.

3. Clinical History Early symptoms of ascariasis, during the initial lung migration, include cough, dyspnea, wheezing, and chest pain. Abdominal pain, distension, colic, nausea, anorexia, and intermittent diarrhea may be manifestations of partial or complete intestinal obstruction by adult worms.

4. Physical Rales, wheezes, and tachypnea may develop during pulmonary migration, particularly in persons with a high worm burden. Abdominal tenderness, especially in the right upper quadrant, hypogastrium, or right lower quadrant, may suggest complications of ascariasis.

5. Differential Diagnoses Biliary Colic Colonic Obstruction Pancreatitis, Acute Pneumonia, Community-Acquired

6. Workup Laboratory Studies Stool examination for ova and parasites. Ascaris larvae may be observed in microscopic wet preparations of sputum during the pulmonary migration phase. CBC counts show eosinophilia during the tissue migration phase of the infection. Serological tests are not clinically useful for ascariasis.

7. Treatment Medical Care Because of the risk of complications, patients with ascariasis who have other concomitant helminthic infections should always undergo treatment for ascariasis first. Medical therapy is usually not indicated during active pulmonary infection because dying larvae are considered a higher risk for significant pneumonitis. Pulmonary symptoms may be ameliorated with inhaled bronchodilator therapy or corticosteroids, if necessary.

8. Surgical Care Recommended criteria for surgical exploration include the following: Passage of blood per rectum Multiple air fluid levels on abdominal radiographs An ill child with abdominal distension and rebound tenderness Unsatisfactory response to conservative therapy Appendicitis and primary peritonitis Hepatobiliary disease Pancreatic pseudocyst

9. Medication Albendazole (Albenza) 400 mg PO single dose Mebendazole (Vermox) 500 mg PO once or 100 mg PO bid for 3 d Pyrantel pamoate (Pin-Rid, Reese's Pinworm Medicine) 11 mg/kg PO to maximum of 1 g

14. Filariasis Filariasis is a disease group affecting humans and animals caused by nematode parasites of the order Filariidae, commonly called filariae. Filarial parasites may be classified according to the habitat of the adult worms in the vertebral host. The cutaneous group includes Loa loa, Onchocerca volvulus, and Mansonella streptocerca. The lymphatic group includes Wuchereria bancrofti, Brugia malayi, and Brugia timori. The body-cavity group includes Mansonella perstans and Mansonella ozzardi.

15. Pathophysiology The filarial life cycle, like that of all nematodes, consists of 5 developmental or larval stages in a vertebral host and an arthropod intermediate host and vector.

16. Clinical History Symptoms of filariasis are species-dependent and body-site–dependent and can be acute or chronic in nature. Lymphatic filariasis The symptoms of lymphatic filariasis predominantly result from the presence of adult worms residing in the lymphatics. The clinical course is broadly divided into asymptomatic microfilaremia, acute phases of adenolymphangitis (ADL), and chronic irreversible lymphedema.

17. Physical Lymphatic filariasis Acute manifestations of lymphatic filariasis is characterized by episodic attacks of fever associated with inflammation of the inguinal lymph nodes, testis, spermatic cord, lymphedema, or a combination of these. Skin exfoliation of the affected body part usually occurs with resolution of an episode. Repeated episodes of inflammation and lymphedema lead to lymphatic damage, chronic swelling, and elephantiasis of the legs, arms, scrotum, vulva, and breasts

18. Lymphatic filariasis resulting from Wuchereria bancrofti infection, which is causing limb lymphoedema, inguinal lymphadenopathy, and hydrocele.

19. Filariasis. Unilateral left lower leg elephantiasis secondary to Wuchereria bancrofti infection in a boy.

20. Filariasis. This is a close-up view of the unilateral lower leg elephantiasis. Note the lymphedema and typical skin appearance of depigmentation and verrucosities (warty changes).

21. Filariasis. Lateral view of the right outer aspect of a leg affected by gross elephantiasis secondary to Wuchereria bancrofti infection.

22. Filariasis. Inner aspect of the lower leg of the male patient showing gross elephantiasis secondary to Wuchereria bancrofti infection.

23. Filariasis. Unilateral left hydrocele and testicular enlargement secondary to Wuchereria bancrofti infection in a man who also was positive for microfilariae.

24. Filariasis. Bilateral hydrocele, testicular enlargement, and inguinal lymphadenopathy secondary to Wuchereria bancrofti infection in a man who also was microfilaremic.

25. Differential Diagnoses Angioedema , Milroy Disease , Asthma , Scrotal Trauma , Hodgkin Disease , Testicular Trauma , Hydrocele , Nonseminomatous Testicular Tumors , Leprosy , Lymphedema , Non-Hodgkin Lymphoma .

26. Workup Laboratory Studies Detection of microfilariae in blood Detection of microfilariae in skin Detection of microfilariae in the eye. Detection of filarial antigen. Detection of filarial antibodies. Urine examination and microscopy. Complete blood cell count.

27. Filariasis. Microfilariae of Mansonella perstans in peripheral blood.

28. Treatment Anthelmintics Ivermectin (Mectizan) 150-200 mcg/kg/d PO as single dose; repeat q2-3mo Diethylcarbamazine (Hetrazan) 6 mg/kg PO qd for 12 d to 3 wk Suramin (Germanin, Antrypol, Naganinum, Naganol) 66.7 mg/kg/d IV in 6 weekly doses Mebendazole (Vermox, Banworm) 100 mg PO bid for 3 d; second course if patient not cured in 3 wk Flubendazole (Fluvermal) 100 mg PO bid for 3 d Albendazole (Albenza, Eskazole, Zentel) 400 mg PO single dose

29. Enterobiasis Pathophysiology E vermicularis is an obligate parasite; humans are the only natural host. Fecal-oral contamination via fomites (toys, clothes) is a common method of infestation. After ingestion, eggs usually hatch in the duodenum within 6 hours. Worms mature in as little as 2 weeks and have a life span of approximately 2 months.

31. Clinical History Patients with enterobiasis are often asymptomatic. Worms may be incidentally discovered when they are seen in the perineal region. If patients are symptomatic, pruritus ani and pruritus vulvae are common presenting symptoms.

32. Physical Patients often have excoriation or erythema of the perineum, vulvae, or both, but infestation can occur without these signs.

33. Differential Diagnoses Appendicitis Ascariasis Cervicitis Contact Dermatitis Giardiasis

34. Workup Laboratory Studies Diagnosis is made by identifying eggs under the low-power lens of microscope. Dilute sodium hydroxide or toluene should be added to the slide.

35. Treatment Anthelmintics Pyrantel (Antiminth, Pin-Rid, Pin-X) 11 mg/kg PO once; not to exceed 1 g; repeat treatment in 2 wk Mebendazole (Vermox) 100 mg PO once; repeat treatment in 2 wk Albendazole (Albenza) 400 mg PO as single dose; repeat in 2 wk if necessary