Unsuspected Toxoplasma gondii empyema in a bone marrow transplant recipient

Toxoplasmosis in Pediatric Hematopoietic Stem Cell Transplantation Patients

Infection due to the protozoa Toxoplasma gondii can be life-threatening in hematopoietic stem cell transplantation (HSCT) recipients. Most cases of toxoplasmosis in HSCT recipients result from reactivation of latent infection in individuals who were Toxoplasma-seropositive before transplantation and did not receive appropriate prophylaxis. Pretransplantation screening with Toxoplasma IgG and IgM antibodies is suggested for all allogeneic HSCT recipients and their donors and all autologous HSCT recipients. Prevention of toxoplasmosis in T. gondii-seropositive HSCT recipients requires primary prophylaxis, preemptive screening, or both. Trimethoprim-sulfamethoxazole (TMP-SMX) is the preferred agent for Toxoplasma prophylaxis and should be continued for 6 months or until the patient is no longer receiving immunosuppression, whichever is longer, assuming that immune reconstitution has occurred. Preemptive weekly screening with whole blood Toxoplasma PCR should be considered for seropositive HSCT recipients if prophylaxis cannot be given or if prophylaxis other than TMP-SMX is used. The signs, symptoms, and radiographic findings of toxoplasmosis in HSCT recipients can be nonspecific, and the diagnosis requires a high degree of suspicion. Common presentations include fever, encephalopathy with mental status changes or seizures, and pneumonia. A Toxoplasma PCR analysis from whole blood (and other body fluids/tissues according to clinical symptoms) should be obtained in patients in whom there is a concern for toxoplasmosis. Treatment with oral pyrimethamine, sulfadiazine, and leucovorin for at least 6 weeks is the first-line therapy and should be followed by secondary prophylaxis. In this article, we review the published literature regarding the epidemiology, clinical presentation, treatment, and prevention of toxoplasmosis in HSCT recipients.

Molecular detection and genetic characterization of Toxoplasma gondii in farmed raccoon dogs (Nyctereutes procyonoides) in Shandong province, eastern China

Toxoplasma gondii is a successful opportunistic parasite, affecting a wide range of vertebrate animals and humans. Genetic diversity of T. gondii in raccoon dogs (Nyctereutes procyonoides) is of great importance to understand the transmission of T. gondii in the environment. However, no information is available about the distribution of genetic diversity of T. gondii infection in raccoon dogs. This study was conducted to estimate the prevalence and genetic characterization of T. gondii from raccoon dogs in Shandong province, eastern China. A total of 314 brain tissue samples of raccoon dogs were collected and genomic DNA was extracted and assayed for T. gondii infection using semi-nested PCR targeting B1 gene. The positive DNA samples were typed at 10 genetic markers (SAG1, SAG2(5'+3' SAG2, alter.SAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico) by multiplex multilocus nested polymerase chain reaction-restriction fragment length polymorphism (Mn- PCR-RFLP) technology. Thirty-five (11.15%) of 314 DNA samples were detected positive. Only six samples were completely typed at all genetic loci, and these samples represented ToxoDB genotype#9. Two sample were typed at 9 genetic loci and one was typed at 8 genetic loci, all of them represented Type I. To our knowledge, this is the first report of genetic characterization of T. gondii in raccoon dogs in China. These results revealed the existence of genetic diversity of T. gondii in raccoon dogs in China. These data provided base-line information for controlling T. gondii infection in raccoon dogs.

Toxoplasma gondii antibodies in cancer patients

To determine Toxoplasma gondii antibodies in cancer patients, 267 cancer patients were studied using ELISA and higher positivity rates of T. gondii IgG were detected than the control. The positivity rates of T. gondii IgG in nasopharyngeal carcinoma, rectal cancer groups were significantly higher than the other cancer groups, but the differences in IgM positivity rates were not significant, demonstrating that there is a likely association between T. gondii infection and some kinds of cancer, especially nasopharyngeal carcinoma and rectal cancer.

Timely diagnosis of disseminated toxoplasmosis by sputum examination

The diagnosis of disseminated toxoplasmosis in a 14-year-old allogeneic bone marrow recipient with graft-versus-host disease was determined by the detection of Toxoplasma gondii tachyzoites in sputum smears. Sputum analysis is a valuable alternative in the clinical assessment of pulmonary toxoplasmosis, especially when conventional invasive techniques are not practicable.