Amoebas eat man alive over months in puzzling, ultra-rare cautionary tale – Ars Technica

The first signs were not systemic, but localized. Red nodules appeared on the man’s legs, which served as the initial clinical presentation. These nodules progressed, developing dark centers that eventually collapsed into deep ulcers. In some areas, the tissue became necrotic, hardening into black scabs.

As the infection took hold, the lesions spread beyond the legs, erupting across the man’s trunk, arms, and neck. The patient’s physical state declined, and his medical history, which included asthma and nasal polyps, became complicated by a systemic condition that challenged early responders.

The Danger of the Autoimmune Misdiagnosis

Before the patient was transferred to Yale, medical providers attempted to isolate the cause of the skin decay through multiple biopsies. These tests returned negative results for common bacterial or fungal pathogens, leaving clinicians without a clear target. However, the biopsies revealed a critical detail: the blood vessels were inflamed and crowded with clumps of immune cells.

This specific finding led doctors to a conclusion. They suspected the man’s own immune system was attacking his blood vessels, triggering the necrotic lesions. Based on this hypothesis, they prescribed immunosuppressant drugs to dampen the response.

The outcome of this treatment was severe. Rather than halting the progression of the lesions, the patient’s condition worsened while on the immunosuppressants. The infection continued to advance, and the lesions spread more aggressively across his body.

By the time the patient reached Yale, the infection had ravaged his physical state. He arrived frail, suffering from a fever and a high heart rate. He was drowsy and confused, having lost 16 pounds. He was no longer fighting a localized skin issue; he was blanketed in lesions.

Hurricane Cleanup and the DNA Trail

Yale physicians began investigating the patient’s recent history, looking for an environmental trigger. The timeline pointed toward Florida, where the man spent his winters. While there, he had participated in cleanup efforts following a hurricane, an activity that exposed him to a red tide caused by algae.

The medical team also noted his existing regimen for asthma, which included the monoclonal antibody drug dupilumab. Given the failure of previous treatments and the continued spread of the lesions, doctors performed another skin biopsy. This time, the analysis revealed cells that resembled amoebas.

The suspicion was confirmed through DNA testing, which identified the pathogen as Acanthamoeba. While the lesions appeared on the skin, researchers noted that nasal rinsing was the most likely route of infection. The man had a history of nasal polyps and used sinus rinses to manage his symptoms, providing a direct pathway for the amoeba to enter the system.

The Struggle for an Experimental Cure

Once the DNA confirmation was secured, doctors moved quickly to implement a five-drug regimen recommended by the Centers for Disease Control and Prevention for such infections. Despite this aggressive pharmacological approach, the patient continued to deteriorate.

With standard protocols failing, the medical team sought a high-risk alternative. They obtained approval from the Food and Drug Administration for a single-patient experimental trial of an antibiotic called nitroxoline. This specific drug had previously shown success in treating a different type of amoeba in another patient, though its efficacy for Acanthamoeba was not established.

The introduction of nitroxoline resulted in specific clinical improvements. His fever broke briefly, and some of the existing lesions showed signs of improvement. Most importantly, the eruption of new lesions ceased.

The case serves as a stark reminder of the volatility of rare infections. The initial misdiagnosis delayed the administration of the correct antimicrobial therapy, and the patient’s condition worsened during the period he received immunosuppressants while the organism was consuming his tissue. For those living in or visiting areas prone to environmental disasters, the risk of opportunistic pathogens remains a hidden variable in post-storm recovery.