Recurrence or Reinfection with Onchocerca lupi in a Child in 2021 and 2024 in New Mexico amid Rising Canine Infections

Onchocerca lupi is an emerging zoonotic parasite in the southwestern United States that typically involves a single site in the head and neck region and is not known to recur after treatment. Human infection with O. lupi is reported in seven cases in the endemic southwestern United States and others from the Old World. Most U.S. cases involved the head and neck, with several presenting with neuroinvasive cervical disease, which can lead to spinal cord injury and meningitis. Recurrent infection has not been described in humans after surgical intervention and/or anthelmintic therapy; however, one case required revision surgery to excise residual worm fragments and inflammation. We present a case of either relapse or reinfection with O. lupi at a separate anatomic location nearly 3 years after completing treatment.