Probable Loa loa-associated encephalopathy following ivermectin administration in a patient with malaria infection: A case report from the Democratic Republic of the Congo

Background: Ivermectin is widely used in mass drug administration programs for the control of onchocerciasis and lymphatic filariasis. In areas where Loa loa is co-endemic, ivermectin administration may precipitate severe neurological adverse events among individuals with high microfilarial densities. We report a case of probable Loa loa–associated encephalopathy following ivermectin administration in a patient with malaria infection. 

Case presentation: A 37-year-old woman from Ituri Province, eastern Democratic Republic of the Congo, presented with altered mental status after receiving ivermectin for loiasis. Her illness began with colicky abdominal pain, mucoid-bloody diarrhea, and polyarthralgia, followed by unsuccessful self-medication. She was subsequently diagnosed with intestinal parasitosis and malaria at a peripheral health facility and treated accordingly, but her neurological condition worsened. On admission to a referral hospital, blood smear examination revealed Plasmodium trophozoites and Loa loa microfilariae. Within 24 h of ivermectin administration, she developed meningeal signs. Cerebrospinal fluid analysis demonstrated the presence of Loa loa microfilariae, with no evidence of bacterial or fungal infection. Following intensified antimicrobial therapy, initiation of albendazole, and supportive care, her neurological status progressively improved. She was discharged after 19 days of hospitalization, and follow-up evaluation confirmed complete clinical recovery with clearance of microfilariae. 

Conclusion: This case fuls criteria for probable Loa loa–associated encephalopathy temporally related to ivermectin administration. It highlights the need for heightened clinical vigilance, microfilarial burden assessment when feasible, and strengthened pharmacovigilance before ivermectin use in Loa loa–endemic and co-endemic settings, particularly in patients with concurrent parasitic infections.