Volume 19, Number 5—May 2013
Letter
Reindeer Warble Fly–associated Human Myiasis, Scandinavia
, Kjetil Åsbakk, Kristian Fossen, Arne Nilssen, Rosario Panadero, and Domenico Otranto
Table
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 |
8/M |
10/M |
10/M |
10/M |
6.5/F |
56/F |
28/M |
| 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 |
| Travel | |||||||
| Dates | 2008 late Jul–early Aug | 2009 Jul 20–Aug 7 | 2010 Jul 7–16 | 2010 Aug 14–19 | 2011 Jul | 1991 Jul | |
| Destination |
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 |
Yes§ |
No |
Yes; at close range |
Yes |
Yes |
|
| 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 |
No |
Enlarged nuchal lymph nodes |
Uveitis, glaucoma, retinal hemorrhage |
| Diagnostic delay, d# | 74 | 25 | 14 | 0 | 0 | 1 | >60 |
| Diagnosis |
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 |
Yes |
No |
No |
Yes |
Yes |
Yes |
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.