Antigenaemia and antibody response to Toxoplasma gondii in human immunodeficiency virus-infected patients.
ABSTRACT Toxoplasma encephalitis in immunocompromised patients results from reactivation of previously acquired (latent) infection. The aim of the study is to assess the antigenaemia and antibody response to Toxoplasma gondii in human immunodeficiency virus (HIV)-infected patients to determine the best marker for early diagnosis of toxoplasmosis in such patients. Indirect enzyme-linked immunosorbent assay (ELISA) for detection of IgG, IgM and IgA anti-toxoplasma antibodies and double-sandwich ELISA for toxoplasma antigen is carried out in serum samples collected from 100 HIV seropositive patients and 75 controls. Toxoplasma-specific IgG, IgM and IgA antibody response and antigenaemia were detected in 12%, 6%, 7% and 14% of HIV-infected patients, respectively. On retrospective analysis of 14 patients with antigenaemia only one had central nervous system (CNS) symptoms attributable to toxoplasma infection. In this patient, the CD4+ cell count was below 50/microL and none of the specific immunoglobulin isotype responses could be detected. The patient showed clinical improvement following specific chemotherapy for toxoplasmosis. In 25 HIV-negative and anti-toxoplasma IgG antibody-positive controls, IgM was detected in two (8%), IgA in five (20%) and antigenaemia in 10 (40%), while 50 HIV seronegative healthy controls were negative for both antigen and antibody responses. The study indicates that detection of toxoplasma antigen in addition to IgG antibody response may prove to be a useful indicator in the early diagnosis of reactivated toxoplasmosis in HIV/AIDS patients.
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ABSTRACT: BACKGROUND: Toxoplasmosis, a zoonotic disease distributed worldwide, is an infection caused by the ubiquitous obligatory intracellular coccidian protozoan organism, Toxoplasma gondii. It is a major public health concern because the disease is serious in terms of mortality or physical and /or psychological sequellae in patients with HIV disease. The aim of the study was to assess the seroprevalence of Toxoplasma gondii IgG and IgM antibodies and associated risk factors in HIV infected and non-infected individuals attending Felege Hiwot referral hospital, Bahir Dar, Northwest Ethiopia. METHODS: A cross sectional study was conducted at Felege Hiwot referral hospital, Bahir Dar, Amhara National Regional State. Venous blood samples were collected from 103 HIV infected pre anti-retroviral therapy patients at Felege Hiwot referral hospital and 101 HIV negative apparently healthy voluntary blood donors at the blood bank. Serum samples were analyzed for anti-Toxoplasma gondii IgG and IgM antibodies using a commercially available ELISA kit. Socio-demographic and associated risk factors for Toxoplasmosis from each individual were also obtained and the data was analyzed using SPSS version 18. RESULTS: Of the examined HIV seropositive individuals, 87.4% (90/103) and 10.7% (11/103) were positive for anti-T. gondii IgG and IgM antibodies, respectively. Multivariate analysis using logistic regression showed that anti-T. gondii seropositivity was independently significantly associated with undercooked or raw meat consumption (adjusted OR=5.73, 95% CI=1.35-24.39; P=0.02) and having contact with cat (adjusted OR= 4.29, 95% CI=1.08-16.94; P=0.04) in HIV positive individuals. In HIV negative apparently healthy blood donors, prevalence of anti-T. gondii antibodies were 70.29% and 2.97% for IgG and IgM, respectively. Multivariate analysis showed that undercooked or raw meat consumption (adjusted OR=6.45, 95% CI=2.16-19.28; p=0.001) and sex (OR=6.79, 95% CI=2.14-21.60; p=0.001) were independently significantly associated with anti-T. gondii IgG seropositivity, with a significantly higher number of males affected than females. CONCLUSION: The present findings showed a high sero-prevalence of anti-T. gondii antibodies in HIV infected pre-ART and HIV non-infected apparently healthy blood donors in Bahir Dar. Consumption of undercooked or raw meat might greatly contribute towards acquiring T. gondii infection in HIV infected pre-ART and HIV non-infected apparently healthy blood donors. It may be appropriate to include routine serological screening test for determination of anti-T. gondii antibodies in HIV infected pre-ART individuals and HIV negative apparently healthy blood donors. In addition, health education towards avoiding eating undercooked and raw meat, and avoiding contact with cats were recommended.Parasites & Vectors 01/2013; 6(1):15. · 3.25 Impact Factor