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An Unusual Case of Hypereosinophilia and Abdominal Pain: AnOutbreak ofTrichostrongylusImported From New Zealand

Emma C. Wall, MRCP DTM&H, Neha Bhatnagar, MRCP, MRCPath, Julie Watson, PhD,

and Tom Doherty, FRCP DTM&H

Departments of Tropical Medicine and Clinical Parasitology, Hospital for Tropical Diseases, London, UK; Department of

Haematology, Royal Cornwall Hospital, Truro, Cornwall, UK

DOI: 10.1111/j.1708-8305.2010.00474.x

We report an outbreak of severe symptomaticTrichostrongylusspp. in travelers visiting a sheep farm in New Zealand. The unusualsource of the outbreak was traced as the use of sheep manure as an organic fertilizer on a salad garden.

Case Report

A62-year-old Caucasian woman presented to hergeneral practitioner (GP) in Cornwall, UK,following a month long trip to visit friends in Australiaand New Zealand in December 2008. She spent a weekon a sheep farm in New Zealand. Shortly afterwards shefelt dizzy and nauseated. She then developed abdominalpain and bloating, followed by diarrhea and weight loss

of 2 kg.Initial investigations performed by her GP showed

a total white cell count of 19.9 109/L (410 109)with an eosinophil count of 9.6 109/L (0.10.4 109). Based on these results she was referred to thelocal hematology service for further investigation ofhypereosinophilia.

Clinical evaluation at the Royal Cornwall Hos-pital did not identify any hepatosplenomegaly orlymphadenopathy. Further investigations showed nor-mal vitamin B12 concentration, autoantibody profile,immunoglobulins, and protein electrophoresis with noevidence of cardiac or pulmonary damage (normal

chest radiograph [CXR],pulmonary function tests, elec-trocardiogram [ECG], cardiac enzymes, and echocar-diogram). Peripheral blood and bone marrow T-cellpopulations had a normal immunophenotype and T-cell receptor rearrangement studies were negative. Bonemarrow aspirate showed an active marrow with 60%

Corresponding Author:Emma C. Wall, MRCP DTM&H,Departments of Tropical Medicine and Clinical Parasitol-ogy, Hospital for Tropical Diseases, Mortimer MarketCentre, Capper Street, London WC1E 6JB, UK. E-mail:

emma.wall@doctors.org.uk

eosinophils and eosinophilic precursors. This was con-firmed on bone marrow trephine with no increase inmast cells. Despite these normal investigations, theeosinophil count continued to rise rapidly, reaching apeak value of 17.9 109/L.

Two months after her initial assessment and dur-ing investigations at the Royal Cornwall Hospital, thepatient received an e-mail from two friends who had

been on the same trip, both of whom had developedsimilar symptoms. Both had been investigated in NewZealand and found to have a peripheral eosinophilia

with Trichostrongylus spp. seen on stool microscopy.Subsequent correspondence established that the farmin New Zealand used sheep manure as an organicfertilizer for their vegetable garden. The faeces fromthese sheep were subsequently found to be positive forTrichostrongylusspp.

On receipt of the first email the patient discussedher symptoms with her GP and was referred to theHospital for Tropical Diseases (HTD) for specialistevaluation. Examination of a stool sample revealed ovaofTrichostrongylusspp. (Figure 1). She was treated with

albendazole 400 mg twice daily for 3 days and recoveredfully within 6 weeks. Her peripheral eosinophilia wasalso resolved completely.

Discussion

Trichostrongylusspecies (pseudo-hookworm) are a groupof zoonotic helminths infecting herbivorous animals.

The prevalence of human infection is very high amongfarmers in the developing world where close contactbetween humans and animals occurs and good sanitationis often not available.1 Infections in pastoralists have

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Figure 1 Ova ofTrichostrongylusspp. from the stool sampleprovided by the patient.

been reported throughout the world, with particularly

highprevalence in Asia andthe Middle East.2 4 Humansusually become infected through consumption of foodor water contaminated with animal faeces, commonly

where faeces are used as a fertilizers. In the UK,Trichostrongylus spp. are endemic in herbivores, mostcommonly sheep.5 However, there are no reported casesof human infection with Trichostrongylus spp. acquiredin this country. This is due to stringent laws preventingthe use of untreated animal manure as a crop fertilizer,separation of grazing land from cultivation of raw foods,and the extensive use of chemical spraying.

Human infection is usually mild with abdominalbloating and minimal systemic symptoms. A low-grade

peripheral eosinophilia is often noted. Of the speciesof Trichostrongylus which cause disease in humans,Trichostrongylus orientalis is the most recognized, butdetailed surveys of people in endemic areas are lack-ing. Trichostrongylus spp. ova are identified on stoolmicroscopy and differentiated by experienced micro-scopists from hookworm and Strongyloidesova by size(Trichostrongylus spp. are classically large measuringapproximately 80 40 m) and shape. Detailed speciesdiagnosis is only possible through DNA analysis, whichis not commonly performed due to its complexity andexpense, particularly as all species respond to the samedrug therapy.6 The patient in this case had unusuallysevere symptoms; this may relate to the high parasitic

load. Due to her rapid response to treatment, speciesanalysis was not performed.

Several cases of infection with Trichostrongylus spp.have been reported in Australia but before this out-break, no published cases appear in the literaturefrom New Zealand, despite Trichostrongylusspp., par-ticularly Trichostrongylus colubriformis, Trichostrongyluscapricola, and Trichostrongylus vitrinusn7,8 being endemicin sheep throughout the country. In one report fromurban Sydney, Australia, two men became symptomaticafter manure from a pet goat was used to fertilize anorganic suburban garden.9 Five cases were reported

from rural Australia with the same transmission methodproposed.10

Hypereosinophilia is a rare condition and this casehighlights a very unusual zoonotic cause. Unexplainedeosinophilia may be due to zoonotic parasitic infectionsand therefore difficult to diagnose. Parasitic infections

should always be included in the differential diagnosisof unexplained eosinophilia. The use of electronic com-munication in this case among the patient, friends, andphysicians in UK and New Zealand facilitated a rapidinvestigation of the cause of the outbreak, diagnosis,and treatment for all those who were affected.

Acknowledgments

The authors would like to thank Dr Chris Morley, BVScBSc (Hons) MVPHMgt Ministry of Agriculture, NewZealand, for tracing the source of the Trichostrongylusfrom the sheep manure that was being used as an organicfertilizer in the salad garden.

Declaration of Interests

The authors state that they have no conflicts of interestto declare.

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