Toxoplasmosis, cryptosporidiosis, and isosporiasis in HIV-negative immunocompromised patients: A single-centre study, Ottawa, Ontario, Canada

Abstract

Background: Historically, patients with HIV have been at the highest risk of infection with opportunistic protozoans such as Toxoplasma, Cryptosporidium, and Isospora. Among patients with HIV who are compliant with antiretroviral therapy, the likelihood of acquiring an opportunistic infection is low. The risk of infection is harder to mitigate in the growing number of HIV-negative immunodeficient patients, such as people with hematological malignancies or those who are post-transplantation. Methods: We conducted a retrospective case series of patients with documented Toxoplasma infections between 2008 and 2017 and with Cryptosporidium and Isospora infections between 2014 and 2017 at the Ottawa Hospital. Results: During the study period, there were 10 confirmed cases of toxoplasmosis, 20 cases of cryptosporidiosis, and 2 cases of isosporiasis. Cryptosporidiosis (95%) and toxoplasmosis (60%) occurred more frequently among HIV-negative patients, whereas isosporiasis cases were limited to HIV-positive patients. Among patients with cryptosporidiosis, the most common underlying cause of immunosuppression in HIV-negative individuals was solid organ transplantation (15.79%), followed by diabetes (10.53%), end-stage renal disease (5.26%), and hematologic malignancy (5.26%). Seventy percent of patients had no known cause of immunosuppression. The most common underlying condition associated with toxoplasmosis was hematological malignancy (50%), followed by solid organ transplantation (33.33%), and solid tumours (16.66%). Conclusions: This study’s results suggest that Cryptosporidium infections are more common among immunocompetent patients in Ottawa, whereas Toxoplasma infections are more common among HIV-negative patients with acquired immunodeficiencies. As the demographics of immunocompromised individuals continue to evolve, screening for protozoal infections in high-risk populations may become clinically important.

Opportunistic Infections in the Immunocompromised: Hiv Vs Non-HIV Patients - A Narrative Review

“…Protozoa are among the most important pathogens that can cause infections in immunocompromised hosts. These microorganisms particularly infect individuals with impaired cellular immunity, such as those with hematological neoplasia, renal or heart transplant patients, patients using high doses of corticosteroids, and patients with acquired immunodeficiency syndrome 100 . Immune compromise can modify the severity and manifestation of some parasitic infections.…”

“…causes mucocutaneous or visceral disease, and Cryptosporidium and Isospora can lead to chronic diarrhea with hepatobiliary involvement 101 . In immunocompetent individuals, infections with Toxoplasma, Cryptosporidium, and Isospora usually have a subclinical presentation and are selflimited [100][101][102] . In immunocompromised individuals, opportunistic protozoans result in more severe disease 101,103 .…”

“…In immunocompromised individuals, opportunistic protozoans result in more severe disease 101,103 . Most studies describing the impact of opportunistic protozoans in immunocompromised hosts have been limited to patients with HIV 100,103 . However, the demographics of immunocompromised individuals are changing with new indications for immunosuppressive treatments, broader organ transplant criteria, and increasing life expectancy for people with chronic diseases 100 .Some studies show that solid organ transplantation and hematologic malignancies have become the most common underlying conditions for patients with toxoplasmosis and cryptosporidiosis.…”

“…Most studies describing the impact of opportunistic protozoans in immunocompromised hosts have been limited to patients with HIV 100,103 . However, the demographics of immunocompromised individuals are changing with new indications for immunosuppressive treatments, broader organ transplant criteria, and increasing life expectancy for people with chronic diseases 100 .Some studies show that solid organ transplantation and hematologic malignancies have become the most common underlying conditions for patients with toxoplasmosis and cryptosporidiosis. The data available upon protozoan infections in non-HIV immunocompromised patients is scarce, not only due to the geographic distribution of the agents but also the rare use of severe immunosuppression in endemic areas.…”

“…Strongyloides stercoralis is an intestinal nematode found worldwide in moist soil contaminated by human feces 100,103 . Occupational exposure to contaminated feces can result in transmission of this disease.…”