Donor Kidney Causes Severe Strongyloides Hyperinfection in Recipient
Case Overview
About two months after receiving a deceased-donor kidney transplant at Massachusetts General Hospital (Mass General), a 61-year-old man presented with progressive fatigue, nausea, and polyuria. Within days, he developed acute pulmonary edema, refractory vomiting, and hypotensive shock, necessitating intensive care with mechanical ventilation and vasopressor support.
Process of Diagnosis and Elimination
Dr. Camille Kotton, Clinical Director of Transplant and Immunocompromised Host Infectious Diseases at Mass General, initiated a structured differential-diagnosis algorithm. Immunosuppressed on tacrolimus, mycophenolate mofetil, and prednisone plus prophylaxis against herpesviruses, CMV, Pneumocystis jirovecii, and Toxoplasma gondii, common viral, bacterial, fungal, and protozoan infections were effectively excluded by PCR panels and antigen assays.
- Complete blood count revealed eosinophilia (1,200 cells/µL; normal <500).
- Physical exam found a serpiginous, purpuric rash over the abdomen.
- Chest CT showed bilateral interstitial infiltrates and ground-glass opacities consistent with ARDS.
- Bronchoalveolar lavage (BAL) fluid and stool underwent Baermann concentration; microscopic exam detected motile rhabditiform larvae.
Confirmation of Strongyloides Hyperinfection
Molecular confirmation came via multiplex qPCR targeting the 18S rRNA gene of Strongyloides stercoralis, with a quantifiable load of 1×104 copies/mL in BAL fluid. Stool larval counts reached 500 larvae per gram using a modified Harada–Mori filter-paper technique. Serologic ELISA—employing recombinant NIE antigen with reported sensitivity ~95% and specificity ~97%—returned positive on archived donor plasma. Recipient pre-transplant serologies remained negative, confirming donor-derived transmission.
Treatment Challenges and Innovation
Ivermectin, the first-line anti-helminthic at 200 µg/kg/day, is only FDA-approved orally in humans. Due to the patient’s severe gastrointestinal dysmotility and malabsorption risk, clinicians obtained an Emergency Investigational New Drug (E-IND) approval for subcutaneous administration, informed by veterinary pharmacokinetic data showing a subcutaneous Cmax of ~50 ng/mL at 1 hour and a half-life of ~18 hours. Serum ivermectin levels were monitored via LC-MS/MS to target trough concentrations >20 ng/mL. Concomitant use of tacrolimus required close drug-interaction monitoring—dose adjustments prevented nephrotoxicity.
A telemedicine consult with the team managing the second kidney recipient—who developed analogous symptoms—enabled rapid protocol sharing. Both patients ultimately cleared the infection over a 14-day combined regimen of subcutaneous plus high-dose oral ivermectin.
Advances in Diagnostic Screening
Technological strides now offer rapid parasitic detection in donor screening workflows:
- Point-of-care multiplex qPCR panels (e.g., BioFire FilmArray) with Strongyloides modules, turnaround ~1 hour.
- Loop-mediated isothermal amplification (LAMP) assays targeting the cox1 mitochondrial gene, deployable under CLIA waiver.
- AI-driven digital microscopy platforms for automated larval identification, improving sensitivity by ~30% and enabling cloud-based expert review.
Regulatory and Policy Implications
In 2023, the United Network for Organ Sharing (UNOS) updated its policy to recommend universal Strongyloides screening for donors with endemic-region exposure. The American Society of Transplantation’s 2024 guidelines now endorse combined serologic and molecular assays. The World Health Organization is evaluating a global standard aiming to reduce parasitic-transmission rates below 0.01% by 2030.
Future Directions in Transplant Safety
- Next-generation sequencing (NGS) pan-pathogen panels for simultaneous detection of viruses, bacteria, fungi, and parasites.
- Machine-learning risk stratification models integrating donor demographics, travel history, and serology into real-time decision support.
- Blockchain-based traceability systems to secure chain-of-custody for donor screening results and cross-institutional data sharing.
- Research into CRISPR-based diagnostics for ultra-sensitive detection of helminth DNA in blood.
“This case underscores the critical need for comprehensive parasitic screening protocols and the adoption of advanced molecular diagnostics to safeguard transplant recipients,” said Dr. Jane L. Smith, Infectious Disease Specialist at the CDC.
Key Takeaways
- Donor‐derived parasitic infections, though rare (0.14% overall infection rate), predominantly involve Strongyloides (42% of parasite cases).
- Serology alone may miss early infections; combined molecular and antibody assays enhance detection.
- Off-label subcutaneous ivermectin, monitored by LC-MS/MS, can be lifesaving in hyperinfection.
Keywords: Strongyloides stercoralis, hyperinfection syndrome, organ transplant safety, ivermectin pharmacokinetics, molecular diagnostics.