Ancylostoma duodenale - Host Immunity, Clinical Manifestation, Complication, Transmission

Host Immunity of Ancylostoma duodenale

Several studies have shown that repeated hookworm infections develop host immunity which eliminates the Ancylostoma duodenale parasite from the host. Repeated infections by hookworm larvae may induce a strong immune response when the circulatory system and respiratory tract are involved during larval migration. As a result, larvae may be encapsulated in various host tissues.

In some cases of hookworm infection, immediate hypersensitivity reactions in the intestine are linked to spontaneous reduction of work and self-cure. This occurs as the parasites release allergic products, high levels of host IgE antibodies and mast cells.

Clinical Manifestations of Ancylostoma duodenale

Parasitic infections caused by Ancylostoma duodenale are symptomatic in 20% to 40% of cases. Depending on the site and phases of infection, the clinical manifestation of Ancylostoma duodenale includes:

1. Skin manifestation

2. Respiratory manifestation

3. Intestinal Manifestations (anaemia)

Skin manifestation

• lesions include small itchy papules

  * such papules are observed 7 days to 10 days at the site of skin penetration by the filariform larva

• ground-itch is the earliest and an important symptom which is seen in a previously sensitized individual

• seen in and around feet- mostly between the toes

• symptoms include itching, oedema, erythema, rash

• complications are caused by secondary bacterial infections

Respiratory manifestation

• caused by the migration of hookworm to the lungs

• symptoms include low-grade fever, cough, pharyngeal dyspnoea, haemoptysis

• dyspnoea occurs when hookworms first break into lung alveoli from the venous circulation

• in severe cases, bronchitis, and pneumonia with pulmonary consolidation may occur

Intestinal manifestations

In the early stages, intestinal manifestations of Ancylostoma duodenale include low-grade fever, vomiting, nausea, abdominal discomfort, anaemia, diarrhoea, etc.

The disease may manifest as iron-deficiency anaemia or hypo-albuminaemia.

Anaemia

The occurrence of anaemia during Ancylostoma duodenale infection is dependent on the worm load present in the intestine as well as the nutritional status of the host. In cases of high hookworm load in addition to poor iron intake or iron deficiency, hypochromic microcytic anaemia occurs.

Anaemia is of three types:

1. Mild anaemia

2. Moderate anaemia

3. Severe anaemia

Mild anaemia

• may not produce clear clinical symptoms

Moderate anaemia

• includes gastrointestinal symptoms such as loss of appetite, diarrhoea, indigestion, constipation

• other symptoms include numbness, headache, tingling sensation, fatigue

Severe anaemia

• results in spleen enlargement, liver enlargement, palpitation, dyspnoea, a low systolic pressure bot normal diastolic pressure

• in children, a prolonged infection may result in mental and physical retardation

• in most cases eosinophilia is common

Complications of Ancylostoma duodenale

Ancylostoma duodenale infection in cases with low protein intake may result in oedema and hypoalbuminaemia.

Prognosis of Ancylostoma duodenale

Infection by Ancylostoma duodenale is rarely fatal and is easily treated. So, the prognosis is excellent.