Vector-borne infections in solid organ transplant recipients

Emerging and neglected zoonoses in transplant population

Zoonoses represent a problem of rising importance in the transplant population. A close relationship and changes between human, animal and environmental health (“One Health” concept) significantly influence the transmission and distribution of zoonotic diseases. The aim of this manuscript is to perform a narrative review of the published literature on emerging and neglected zoonoses in the transplant population. Many reports on donor-derived or naturally acquired (re-)emerging arboviral infections such as dengue, chikungunya, West Nile, tick-borne encephalitis and Zika virus infection have demonstrated atypical or more complicated clinical course in immunocompromised hosts. Hepatitis E virus has emerged as a serious problem after solid organ transplantation (SOT), leading to diverse extrahepatic manifestations and chronic hepatitis with unfavorable outcomes. Some neglected pathogens such as lymphocytic choriomeningitis virus can cause severe infection with multi-organ failure and high mortality. In addition, ehrlichiosis may be more severe with higher case-fatality rates in SOT recipients. Some unusual or severe presentations of borreliosis, anaplasmosis and rickettsioses were also reported among transplant patients. Moreover, toxoplasmosis as infectious complication is a well-recognized zoonosis in this population. Although rabies transmission through SOT transplantation has rarely been reported, it has become a notable problem in some countries. Since the spreading trends of zoonoses are likely to continue, the awareness, recognition and treatment of zoonotic infections among transplant professionals should be imperative.

Tick-borne illness after transplantation: Case and review

Tick-borne infections in solid organ transplant recipients are an infrequent and difficult diagnostic challenge owing to multiple routes of acquisition and unusual presentations. A 67-year-old male recipient of a combined liver and kidney transplant presented with recurrent fevers following surgery. Standard microbiologic workup was non-diagnostic. Shortness of breath, confusion, lethargy, and hypotension developed along with progressive anemia, requiring multiple blood transfusions. Workup suggested hemolysis and review of the peripheral smear was diagnostic for Babesia microti infection. Tick transmission, transmission via blood products, and/or the transplanted organ were all considered. More extensive questioning revealed a history of intermittent fevers for several months before transplantation. Testing of pre-transplant blood was positive for B. microti antibodies, suggesting infection prior to transplantation. The delayed diagnosis of babesiosis in this patient highlights the need for a detailed exposure history prior to transplantation, as well as considering the potential for atypical presentations of tick-borne infections in immune suppressed solid organ recipients. Furthermore, this case illustrates the importance of early Infectious Disease consultation to meet the challenges exhibited by febrile transplant patients. Infectious Diseases physicians are trained to consider, diagnose, and treat tick-borne infections, contributing to improved clinical outcome.

Lyme carditis in an immunocompromised patient

We present a case of a 68-year-old man with a history of liver transplant and of chronic immunosuppression therapy who presented to the emergency department (ED) for fevers and worsening fatigue for two days. On further investigation, the patient was found to have a new first-degree heart block on his electrocardiograph. Coupled with the history of a recent tick bite, the patient was diagnosed with vector-borne carditis. Although the patient's titers for various vectors remained negative, due to a long history of immunosuppression, he was treated for Lyme disease and his heart block completely resolved with antibiotic treatment. We describe details of the case as well as discuss the impacts of immunosuppression on vector-borne disease. Immunosuppressed patients represent a special population and can present with chief complaints made even more complicated by their medical history, and this case illustrates the importance of being mindful of how immunosuppression can affect a patient's presentation. As the efficacy of antirejection medications improved, the ED may see an increasing number of patients with solid organ transplants. A greater understanding of this special patient population is key to formulating optimal treatment plans.