Zoonotic Onchocerca lupi Infection in a 22-Month-Old Child in Arizona: First Report in the United States and a Review of the Literature

Abstract

Abstract. A 22-month-old girl presented with neck pain and stiffness and magnetic resonance imaging showed an extradural mass extending from C2 through the C4 level with moderate to severe compression of the cord. A left unilateral C2-C4 laminectomy was performed revealing an extradural rubbery tumor; a small biopsy was obtained. Examination of stained tissue revealed the presence of a parasitic worm that was identified as a gravid female Onchocerca lupi. A magnetic resonance imaging at 7 weeks follow-up showed a significantly decreased size of the enhancing lesion and the patient's symptoms gradually resolved. This is the first report of zoonotic O. lupi in the United States. The parasite has been reported in dogs and cats in the western United States, and from people in four cases reported from Europe. A great deal more needs to be learned, including full host range and geographic distribution, before we fully understand O. lupi infections in animals and man.

Human case of Onchocerca lupi infection, Germany, August 2014

“…In one case also multiple eye nodules were observed [8]. An extradural infection with spinal cord compression was seen in a 22-month-old girl [9]. The presumed arthropod vector for O. lupi is unknown, but might be a simuliid black fly in analogy to the biology of Onchocerca volvulus [11], the agent of human river blindness.…”

“…It clusters in particular with Onchocerca lupi sequences from Portugal (canine infection, GU365879 (100% nt identity, 393 of 393 nt)) and Iran (human infection, JN863696 (99% nt identity, 393 of 395 nt)), followed by those from Turkey (human infection, HQ207645 (99% nt identity, 373 of 375 nt)) and California (canine infections, KC763783 (100% nt identity, 326 of 326 nt) and KC763784 (97% nt identity, 383 of 396 nt)). [9,10]. The clinical picture in humans is characterised by the development of a bulbar subconjunctival nodule [5][6][7]10].…”

Case report of an epidural cervical Onchocerca lupi infection in a 13-year-old boy

“…Her symptoms improved after surgery and eventually resolved by her 7-month follow-up examination at the time the case was reported. 5 At her most recent 28-month follow-up with Dr. Feiz-Erfan, she was neurologically stable and remains on a regimen of ivermectin therapy 4 times per year.…”

“…No other Onchocerca species have been reported to infect the intradural or extradural space of the cervical spine. [4][5][6]9,15,16,21,23 No prior reports have documented the treatment of CNS O. lupi infections in humans; however, ivermectin has been demonstrated to kill O. volvulus larvae and promote the death of adult worms when administered 4 times per year. The first patient diagnosed with O. lupi infection of the epidural cervical spine was also treated with ivermectin, 5 and interestingly, was also a Native American residing in northeastern Arizona.…”

“…While isolated spinal cysticercosis without intracranial involvement is rare, patients with spinal echinococcosis present more often with primary spinal infection. 1,3,5,[7][8][9][10][11][12][13][14][17][18][19][20]22 In a recent review of 467 cases of spinal echinococcosis by Neumayr et al, 13 17.9% were primary spinal infections without intracranial involvement.…”