Incidental hepatic schistosomiasis in a liver transplant recipient

The Potential Role of Schistosome-Associated Factors as Therapeutic Modulators of the Immune System

The parasites and eggs of helminths, including schistosomes, are associated with factors that can modulate the nature and outcomes of host immune responses, particularly enhancing type 2 immunity and impairing the effects of type 1 and type 17 immunity. The main species of schistosomes that cause infection in humans are capable of generating a microenvironment that allows survival of the parasite by evasion of the immune response. Schistosome infections are associated with beneficial effects on chronic immune disorders, including allergies, autoimmune diseases, and alloimmune responses. Recently, there has been increasing research interest in the role of schistosomes in immunoregulation during human infection, and the mechanisms underlying these roles continue to be investigated. Further studies may identify potential opportunities to develop new treatments for immune disease. In this review, we provide an update on the advances in our understanding of schistosome-associated modulation of the cells of the innate and adaptive immune systems as well as the potential role of schistosome-associated factors as therapeutic modulators of immune disorders, including allergies, autoimmune diseases, and transplant immunopathology. We also discuss potential opportunities for targeting schistosome-induced immunoregulation for future translation to the clinical setting.

Intestinal parasites including Cryptosporidium, Cyclospora, Giardia, and Microsporidia, Entamoeba histolytica, Strongyloides, Schistosomiasis, and Echinococcus: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of intestinal parasites in the pre- and post-transplant period. Intestinal parasites are prevalent in the developing regions of the world. With increasing travel to and from endemic regions, changing immigration patterns, and the expansion of transplant medicine in developing countries, they are increasingly recognized as a source of morbidity and mortality in solid-organ transplant recipients. Parasitic infections may be acquired from the donor allograft, from reactivation, or from de novo acquisition post-transplantation. Gastrointestinal multiplex assays have been developed; some of the panels include testing for Cryptosporidium, Cyclospora, Entamoeba histolytica, and Giardia, and the performance is comparable to conventional methods. A polymerase chain reaction test, not yet widely available, has also been developed to detect Strongyloides in stool samples. New recommendations have been developed to minimize the risk of Strongyloides donor-derived events. Deceased donors with epidemiological risk factors should be screened for Strongyloides and recipients treated if positive as soon as the results are available. New therapeutic agents and studies addressing the optimal treatment regimen for solid-organ transplant recipients are unmet needs.

Parasitic Infections Associated with Unfavourable Outcomes in Transplant Recipients

Introduction. The immunosuppression used after transplantation (Tx) is associated with an increased risk of opportunistic infections. In Europe, parasitic infections after Tx are much less common than viral, bacterial and fungal ones. However, diseases caused by parasites are very common in tropical countries. In the last years the number of travellers with immunosuppression visiting tropical countries has increased. Methods. We performed a literature review to evaluate a risk of parasitic infections after Tx in Europe. Results. There is a real risk of parasitic infection in patients after Tx travelling to tropical countries. Malaria, leishmaniasis, strongyloidiasis and schistosomiasis are the most dangerous and relatively common. Although the incidence of these tropical infections after Tx has not increased, the course of disease could be fatal. There are also some cosmopolitan parasitic infections dangerous for patients after Tx. The greatest threat in Europe is toxoplasmosis, especially in heart and bone marrow recipients. The most severe manifestations of toxoplasmosis are myocarditis, encephalitis and disseminated disease. Diarrhoea is one of the most common symptoms of parasitic infection. In Europe the most prevalent pathogens causing diarrhoea are Giardia duodenalis and Cryptosporidium. Conclusions. Solid organ and bone marrow transplantations, blood transfusions and immunosuppressive treatment are associated with a small but real risk of parasitic infections in European citizens. In patients with severe parasitic infection, i.e., those with lung or brain involvement or a disseminated disease, the progression is very rapid and the prognosis is bad. Establishing a diagnosis before the patient's death is challenging.

Helminths in organ transplantation

With transplantation becoming an increasingly routine form of treatment for diverse populations, and with international travel becoming ever more accessible and affordable, the danger of transplantation-mediated helminth infections, exacerbated by coincident immunosuppression, must be considered. In this Review, we attempt to catalogue all clinically-relevant helminthiases that have been reported to coincide with transplantation, whether by transplantation-mediated transmission, reactivation of latent infections in an immunosuppressed context, or possible de-novo infection during the immunosuppressed peritransplant period. Helminthiasis has been reported in cases of kidney, liver, bowel, pancreas, heart, lung, and stem-cell transplant, and blood transfusion. For each helminthiasis, known risk factors, symptoms, and suggested options for screening and treatment are given. We conclude that helminths are a small but important and potentially severe source of disease after transplantation, and, with options for diagnosis and treatment, these pathogens warrant greater consideration during organ implantation. The achievement of immunological tolerance using helminth-derived products is also an exciting future prospect.

Multiple parasitic infections in a cardiac transplant recipient

Infectious complications represent an important cause of morbidity and death in patients with transplant. Parasitic infections are less frequent than viral and bacterial agents, and are often overlooked. We describe the case of a 13-year-old adolescent, born in São Tomé Island, who was under immunosuppressive therapy after a cardiac transplant. The patient had an intermittent course of diarrhoea, abdominal pain and vomiting. She was admitted dehydrated, and Strongyloides stercoralis, Schistosoma intercalatum and Cystoisospora belli were isolated in her stools. The patient was treated with ivermectin, albendazole, praziquantel and ciprofloxacin with clinical and microbiological resolution. Her immunosuppressive therapy was reduced during hospitalisation. We believe that the parasitic infection was a result of a recrudescence of dormant infections acquired in her homeland. To the best of our knowledge, there are no reports of cystoisosporiasis or schistosomiasis in heart transplant recipients.