Toxoplasmosis: an update on clinical and therapeutic aspects

Seroprevalence of Toxoplasma gondii antibodies among Atayal aboriginal people and their hunting dogs in northeastern Taiwan

Atayal aborigines, living at an altitude of 1,500-1,600 m in northeastern Taiwan, still hunt for wild animals with the help of hunting dogs. In this study, the latex agglutination test (LAT) was used to detect sera anti-toxoplasma antibodies in this community as a measure of their exposure to Toxoplasma gondii. The positive rates for sera anti-toxoplasma antibodies were 21.8% and 19.6%, respectively, in 422 Atayal and 51 hunting dogs tested. Neither of the positive rates were found to be significantly different between male (22.1%) and female Atayal (21.4%), or between humans (21.8%) and dogs (19.6%) (P > 0.05) when compared by the Chi-Squared test (chi 2-test). A significant difference was observed between the positive rates in adults (28.3%) and children (18.7%) (P < 0.05), and the age pattern of prevalence is consistent with an increasing duration of exposure to Toxoplasma gondii with age. The consumption of raw liver of wild animals or insufficiently cooked meat may be the major mode of transmission of toxoplasmosis in Atayal.

High predictive value of Toxoplasma gondii IgG antibody levels in HIV-infected patients for diagnosis of cerebral toxoplasmosis

The results of serological tests for Toxoplasma gondii IgG in 31 HIV-infected patients with toxoplasmic encephalitis (TE) and 49 HIV-infected patients seropositive for Toxoplasma gondii but without TE were compared. All patient had a CD4+ lymphocyte count < 150/microliters. Of the TE patients, 22 (71%) were designated as having relatively high IgG levels on the basis of the following Toxoplasma IgG titre combination: Sabin-Feldman test > or = 1:256, indirect hemagglutination test > or =1:1024, direct agglutination test > or = 1:14,580. Only 3 patients without TE had relatively high IgG titres. Relatively high IgG titres indicated TE with a positive predictive value of 88% in HIV-infected patients with CD4+ cell counts < 150/microliters, and could be observed in most patients several months prior to the first clinical and radiological signs of TE.

Therapeutic approaches for AIDS-related toxoplasmosis

OBJECTIVE

To summarize current knowledge of prophylaxis and treatment of AIDS-related toxoplasmosis.

DATA SOURCES

A MEDLINE search (1985-1994) was used to identify pertinent literature, including reviews.

STUDY SELECTION AND DATA EXTRACTION

All articles were considered for possible inclusion in the review. Pertinent information, as judged by the authors, was selected for discussion.

DATA SYNTHESIS

Trimethoprim/sulfamethoxazole (TMP/SMX) appears to be useful for prophylaxis against toxoplasmosis in patients with AIDS. The most effective TMP/SMX dose for prevention of toxoplasmosis needs to be determined. Dapsone in combination with pyrimethamine therapy may be an effective alternative for toxoplasmosis prophylaxis. The most effective regimen for the treatment of AIDS-related toxoplasmosis is the combination therapy of pyrimethamine/sulfadiazine. In patients who cannot tolerate sulfadiazine therapy because of adverse effects or allergy, pyrimethamine with clindamycin therapy may be considered as a second-line alternative. Lifelong suppressive therapy is required after either treatment regimen to prevent relapse. Other newer agents such as azithromycin, clarithromycin, atovaquone, or timetrexate-leucovorin need further studies to confirm their true effectiveness in the treatment of toxoplasmosis.

CONCLUSIONS

TMP/SMX remains a useful agent in prophylaxis against toxoplasmosis. Pyrimethamine/sulfadiazine is the most effective combination in the treatment of acute toxoplasmosis.

Toxoplasmosis of the bladder: case report and review of the literature

Toxoplasma gondii is an intracellular parasite that is responsible for an asymptomatic or minimally symptomatic lymphadenopathy syndrome, which in the immunocompromised host can be life threatening. Toxoplasmosis commonly affects the central nervous system. Genitourinary involvement is uncommon with reported cases limited to Toxoplasma orchitis and the nephrotic syndrome. To our knowledge we report the first case of toxoplasmosis of the bladder as an intravesical mass without central nervous system or other organ involvement in a young man with the acquired immunodeficiency syndrome.