Capillaria hepatica pseudoinfection.

A 54-year-old male Matsigenka native from the Manu jungle of Peru presented with the eggs shown in Figure 1. Kato Katz (Figure 2) testing revealed 1,500 eggs/g stool. The white blood cell count with differential, liver enzymes, and sputum examination were normal. No treatment was administered; however, repeated stool testing was negative. Pseudocapillariasis caused by Capillaria hepatica was diagnosed. The transient shedding of C. hepatica eggs (which are not usually found in the stools in hepatic capillariasis), lack of eosinophilia, and normal liver enzymes supported the diagnosis. The patient admitted eating liver of a South American Tapir (Tapirus terrestris) shortly before testing. These animals harbor unembryonated non-infective C. hepatica eggs in the liver parenchyma.1 The unembryonated eggs reach the environment after the infected animal dies or eggs are shed in the stools of predators feeding on infected carcasses. After spending 4–8 weeks in the environment, eggs become embryonated and are able to infect the liver if ingested. Hepatic capillariasis is an uncommon human zoonotic disease distributed worldwide. It causes prolonged fever, hepatomegaly, and abdominal pain associated with eosinophilia. In contrast, C. hepatica pseudoinfection caused by feeding on livers harboring unembryonated eggs is asymptomatic.2

Figure 1.

Spontaneous rapid sedimentation test. Egg with a thick striated wall (open arrows) and flat bipolar plugs (arrow) compatible with C. hepatica (Magnification: 400×; scale bar: 50 μm).

Figure 2.

Kato Katz test showing the same type of eggs (Magnification: 400×; scale bar: 50 μm).