Diagnosis of human fascioliasis in Arusha region, northern Tanzania by microscopy and clinical manifestations in patients

Abstract

Background: Human fascioliasis (HF) is a zoonotic disease that has been identified in many countries worldwide. This report concerns the identification and clinical management of cases of human fascioliasis in the suburbs of Arusha city, northern Tanzania in 2013. Fascioliasis is included among the WHO's Neglected Tropical Diseases as a plant transmitted trematode infection. Human fascioliasis has not been described before in the East Africa region, including Tanzania.

Methods: Patients presenting at a primary healthcare centre in Arusha Region, northern Tanzania provided fresh stool samples for routine ova and parasite screening (saline and iodine preparations). Subsequent stool samples were preserved in 5 % formalin in saline and subjected to ether sedimentation for examination.

Results: Out of 1460 patients, 305 (21 %) were diagnosed positive for fascioliasis based on the demonstration of brownish, oval eggs with inconspicuous opercula in stool. Two distinct egg sizes were identified; large 170-212.5 by 115-150 μm (mean 194.5 by 130.5 μm) and smaller eggs 120-150 by 87.5 - 112.5 μm (mean 138.8 by 101 μm). Clinically, patients presented with fever (39 - 40 °C) and abdominal pain. Some patients had pruritis around the mouth and their lips were swollen. 3 patients were treated and cured with single dose Triclabendazole. The remaining 302 patients were treated with Nitazoxanide and 122 (40 %) were cleared of infection with a single course. Snails of the genus Lymnaea were found in the surroundings.

Conclusions: This report serves to remind medical professionals in East Africa that HF is a probable differential diagnosis in patients presenting with similar symptoms. It is possible to diagnose fascioliasis by light microscopy although specific antigen tests are required for confirmation. Human fascioliasis however, has not been described or reported in Tanzania before and begs further investigation.

Fig. 1

a and b Eggs of Fasciola (a, small size; 130.5 by 102 μm and b, large 205 by 148 μm) as seen in an iodine stained stool sample after formol-ether sedimentation. Original magnification x400 (arrow indicates position of the inconspicuous operculum; bar scale = 50 μm and 75 μm)

Fig. 2

A snail of the genus Lymnaea, one of the snails which act as intermediate host of Fasciola on a piece of vegetation from a natural stream

Fig. 3

Frequency of occurrence of fascioliasis in males and females stratified from 1 to 11 years based on stool examination

Fig. 4

Frequency of diagnosis of fascioliasis in males and females of all age groups from September 2012 to October 2013

Flow Chart

Showing Results of stool examination of 1460 stool samples for Fasciola eggs (pre- and post- treatment and effect of treatment). *Side effects of Nitazoxanide were noticed more frequently and severely among females than males (data not shown). All patients presented with abdominal pain (day 2–4), diarrhea (day 2–3), pharyngitis and flu-like syndrome (day 2–6) of treatment. In a few patients with pruritis, swelling and rashes of hands and feet was observed