Parasitic infections in children: Case

This child has a soil-transmitted helminth infection, specifically hookworm, detected through routine refugee arrival screening. His iron-deficiency anaemia with a haemoglobin of 82 grams per litre and ferritin of 6 is the direct consequence of chronic occult blood loss from hookworm feeding on the intestinal mucosa, and his eosinophilia of 1.8 reflects the tissue migration phase of the larval life cycle. The Southeast Asian refugee camp exposure is the key epidemiological clue, and the screening stool microscopy is the confirmatory test. [2]

Clinical findings

The key findings are the profound iron-deficiency anaemia, the eosinophilia, and the hookworm ova on stool microscopy. The anaemia is the primary clinical concern and reflects months to years of low-grade intestinal blood loss from adult hookworms that attach to the small intestinal mucosa and feed on blood. Each adult worm consumes approximately 0.2 millilitres of blood per day, and a heavy burden over time produces significant iron depletion. The microcytic hypochromic picture with a very low ferritin confirms iron deficiency rather than anaemia of chronic disease. [2]

The eosinophilia is an expected finding in tissue-migrating helminths. Hookworm larvae penetrate the skin, travel via the bloodstream to the lungs, ascend the airways, and are swallowed before maturing in the small intestine. The pulmonary migration phase provokes eosinophilia, and the value of 1.8 is moderate and consistent with active tissue migration. The absence of respiratory symptoms in this child does not exclude pulmonary migration, because the larval burden may be too small to cause clinical Loeffler syndrome. [1]

The coinfection risk is important to consider. A child with hookworm from a tropical refugee setting is also at risk for other soil-transmitted helminths including Ascaris and Trichuris, and critically for Strongyloides stercoralis. Because this child is a refugee from Southeast Asia, the Strongyloides serology must also be checked, even if the initial stool does not show larvae, because stool microscopy for Strongyloides has low sensitivity due to intermittent and low larval output. [3]

Management

Treat the hookworm with albendazole as a single oral dose, which kills the adult worms and interrupts egg deposition. Mebendazole is an alternative. The anaemia requires iron supplementation for at least three months to replete iron stores, and the child should have a repeat full blood count and ferritin at follow-up to confirm haematological recovery. Dietary counselling about iron-rich foods supports the recovery. [1]

Screen for coinfection with Strongyloides serology, because this child's exposure history places him at high risk, and because the consequences of missing Strongyloides are potentially catastrophic if he ever receives immunosuppression. If the serology is positive, treat with ivermectin for two days, which is the drug of choice and is more effective than albendazole for Strongyloides. The essential principle is that every refugee or migrant child from a tropical area should have Strongyloides serology as part of their arrival assessment, and the result should be checked and acted upon before any future immunosuppression. [3]

The broader refugee health screen for this child should include repeat stool microscopy for ova, cysts, and parasites on two further samples to identify any additional helminths, schistosomiasis serology if from an endemic region, hepatitis B and C screening, tuberculosis screening with a tuberculin skin test or interferon-gamma release assay, and a nutritional assessment. The parasitic component of the refugee screen is a quality marker of arrival health care and prevents long-term complications. [1]

Complications and follow-up

The dominant complication of untreated hookworm is progressive iron-deficiency anaemia that impairs growth, cognitive development, and exercise tolerance. In this child, the haemoglobin of 82 grams per litre is moderate to severe and may cause fatigue, pallor, and poor concentration, though children often tolerate chronic anaemia well. Cardiac failure is a risk with very severe anaemia but is uncommon at this level. The iron replacement alongside worm eradication leads to steady haematological recovery over weeks to months. [2]

Follow-up should include a repeat stool examination at two to four weeks to confirm clearance of hookworm ova, a repeat full blood count and ferritin at one to three months to document iron recovery, and Strongyloides serology with ivermectin treatment if positive. The child's growth should be monitored, because chronic parasitic infection and iron deficiency can contribute to growth faltering that recovers with treatment. If the Strongyloides serology was positive and treated, a follow-up serology at three to six months helps confirm cure, because persisting antibody indicates ongoing infection that requires further treatment. [3]