Toxoplasmosis in Immunocompetent Military Veteran with Overseas Field Deployment

Open Access

Abstract

Introduction: Toxoplasmosis is caused by infection with the protozoan Toxoplasma gondii (T. gondii), an obligate intracellular parasite. T. gondii infects a large portion of the world's population, but uncommonly causes clinically significant disease. Those that are at greatest risk for more severe disease with toxoplasmosis are the immunologically impaired, fetuses, and newborns. T. gondii infection in immunocompetent patients can present as a self-limiting acute infection, or as an acute systemic disease. There are three main T. gondii genotypes, I, II, and III, with varying geographical prevalence. T. gondii is most commonly acquired via ingestion of infectious oocysts, from the environment, tissue cysts from contaminated food items, vertical transmission, or via organ transplantation from an infected donor. Diagnosis can be made via histological and serologic testing in suspected patients. Seropositive testing should be considered within the clinical context, as IgM antibodies may persist for months to years. IgG antibody avidity patterns further help delineate acute versus chronic infections. Histopathology from tissue biopsy of lymphadenopathy is more commonly pursued to establish diagnosis in immunocompetent patients. Case Report: We present a 37-year-old male who presented to the clinic with persistent bilateral non-tender occipital lymphadenopathy of two months duration. Patient also endorsed an acute fluid filled blister on the penis, recurrent cold sores, and significant fatigue. Review of systems were unremarkable. Patient's immunizations were up-to-date. Patient is an active military serviceman with history of overseas deployment. Patient reports consuming undercooked meat overseas, as well as game meat preparation while hunting. Similar symptoms were also reported by another fellow veteran. Laboratory studies revealed normal CBC, CMP, and TSH. HIV, gonorrhea, and chlamydia testing were negative. Urology referral found no abnormalities. Aspiration biopsy of the right occipital lymph node demonstrated granulomas and aggregates of histiocytes compatible with reactive hyperplasia. Findings were suggestive of toxoplasmosis and no malignancy was found. Follow up T. gondii serological testing results revealed Ab IgM: 104 AU/ML (reference range 0.0-7.9). Toxoplasma gondii Ab IgG: >400 AU/ML (reference range 0.0-7.1), which were consistent for active infection. Patient was referred to Infectious Disease and supportive therapy was recommended. A three month follow up showed improvement in symptoms. Discussion: Although acute infections with T. gondii in immunocompetent patients typically are self-limiting, more serious systemic infections may occur. A pyrimethamine-containing antibiotic regimen is recommended for treating systemic infections. We propose educating high-risk individuals with appropriate preventive measures, which may be beneficial in preventing Toxoplasmosis.