Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 19, Number 5—May 2013

Reindeer Warble Fly–associated Human Myiasis, Scandinavia

Boris KanComments to Author , Kjetil Åsbakk, Kristian Fossen, Arne Nilssen, Rosario Panadero, and Domenico Otranto
Author affiliations: Karolinska University Hospital, Stockholm, Sweden (B. Kan); Norwegian School of Veterinary Science, Tromsø, Norway (K. Åsbakk); University Hospital of Northern Norway, Tromsø, Norway (K. Fossen); Tromsø University Museum, Tromsø (A. Nilssen); Universidad de Santiago de Compostela, Lugo, Spain (R. Panadero); Università degli Studi di Bari, Valenzano, Italy (D. Otranto)

Main Article


Myiasiss caused by warble reindeer fly (Hypoderma tarandi), Scandinavia, 1991–2012*

Characteristic Case-patient no.
1 2 3 4† 5 6 7‡
Age, y/sex
Date of symptom onset 2008 Sep 15 2009 Aug 15 2010 Sep 12 2010 Sep 3 2010 Dec 3 2011 Oct 10 1991 Aug
Signs and symptoms
Enlarged occipital and retroauricular lymph nodes
Eggs in scalp hair; enlarged occipital and cervical lymph nodes
Forehead swelling
Enlarged occipital and cervical lymph nodes
Forehead and eyebrow swelling
Occipital swelling
Occipital swelling
Dates 2008 late Jul–early Aug 2009 Jul 20–Aug 7 2010 Jul 7–16 2010 Aug 14–19 2011 Jul 1991 Jul
Norway, extreme northeast: patient resides in Troms County where reindeer are occasionally seen
Sweden: Lapland
Sweden: Kiruna, Riksgränsen, Abisko (several short hiking tours) Norway: Bodö
Sweden: family undertook a 5-d hiking tour in Lunndörrsfjällen, a mountain area in Jämtland County
Norway: Lapland
Sweden: short trips to Arvidsjaur (Lapland) and Jämtland Mountains
Observed reindeer
Yes; at close range
Migratory swellings, no. Temple, 1 Head, 1; forehead, 5 Forehead, 4; eyelid, 1; behind ear, 1 Forehead and eyelid, 5 Forehead and eyelid, 2 Head, temple, eyelid, >5 Head, >5
Fever Yes No No Yes No No No
Eosinophilia (highest value)¶ Yes (1,0) Yes (0,6) Yes (0,8) Yes (3,8) No No Unknown
Other signs and symptoms
Uveitis, failure to gain weight
Localized exanthema
Itching of scalp, enlarged retroauricular lymph nodes, headache, uveitis
Fever, headache, nausea
Enlarged nuchal lymph nodes
Uveitis, glaucoma, retinal hemorrhage
Diagnostic delay, d# 74 25 14 0 0 1 >60
Positive serology, morphologic identification of larva
Positive serology, identification of eggs
Positive serology, molecular identification of larva
Positive serology
Positive serology
Negative serology**
Negative. serology in 2011 and 2012, morphologic identification of larva in 1991
Drugs received
Ivermectin No 5 doses 5 doses†† 5 doses 3 doses 2 doses No
Antihistamines No Yes Yes Yes Yes Yes Unknown
Oral steroids
Steroids, antimicrobial drugs given after surgery
Outcome After eye surgery glaucoma; visual acuity 0,9 Good Eye surgery; visual loss, right eye Good Good Good Eye surgery; visual loss, right eye

*Patients 8 and 9 are not included in the table because myiasis did not develop in them.
†Patients 4 and 5 are siblings.
‡Patient 7 was discovered by the father of patients 4 and 5 among his acquaintances, suggesting the possibility of additional unreported cases in the population.
§In Jukkasjärvi (Sweden), the child had visited an enclosure where the reindeer were agitated because of swarms of flies.
¶Referent 0–0.5 × 109/L.
#Interval between date of first visit for myiasis-associated symptoms and date when treatment began.
**The diagnosis could not be confirmed, but her clinical picture and response to treatment were similar to those of other patients.
††Ivermectin was given first after eye surgery.

Main Article

Page created: April 19, 2013
Page updated: April 19, 2013
Page reviewed: April 19, 2013
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.