Marek Malý

Incidence and clinical and immunological characteristics of primary Toxoplasma gondii infection in HIV-infected patients

OBJECTIVES To determine the incidence and laboratory characteristics of primary Toxoplasma gondii infection in HIV-infected individuals. METHODS This retrospective study was conducted between 1988 and 2012 on a cohort of 1130 HIV-infected patients at the AIDS Center Prague. Toxoplasma serology, standard laboratory parameters, and health status were evaluated at 3-6-month intervals for all patients. RESULTS The total person-time of follow-up of patients at risk of Toxoplasma seroconversion was 3046.3 years; there were 14 primary T. gondii infections, yielding an incidence rate of 0.0046 (95% confidence interval 0.0027-0.0078). Most of the subjects were clinically asymptomatic, but in one case seroconversion was accompanied by transient cervical lymphadenopathy. The CD4+ T-lymphocyte count geometric mean increased from 418 (95% confidence interval 303-579) cells/μl before seroconversion to 501 (95% confidence interval 363-691) cells/μl after seroconversion (p = 0.004), while other parameters (CD8+ T-lymphocytes, natural killer cells, viral load, beta2-microglobulin, total immunoglobulins) remained unchanged. As compared to the control group, patients with primary toxoplasmosis had higher initial levels of total immunoglobulins IgA and IgG and a tendency to higher CD8+ T lymphocyte counts. CONCLUSIONS Neither the incidence nor the course of the primary Toxoplasma infection was influenced by the immune status of the patients. Immune parameters of patients with primary Toxoplasma infection did not differ from those of the controls.

Prevalence and Incidence of Toxoplasma Infection in HIV-Positive Patients in the Czech Republic

TOXOPLASMOSIS is a major opportunistic infection infecting approximately 30% of the Czech general population (Petersen, Pollak, and Reiter-Owona, 2001). In people with latent toxoplasmosis, who subsequently become infected with HIV, the Toxoplasma infection in the latent form proceeds as such. Less frequently, a patient is first infected with HIV and then with Toxoplasma. However, deterioration of the immune system (usually with a decline of CD4 T-lymphocyte counts under 100/ml) can result in recrudescence of latent infection along with the development of clinically manifest toxoplasmic encephalitis or extracerebral toxoplasmosis. Since toxoplasmosis in HIV patients is a dynamic process, sometimes gradual and other times overtly progressive, only a single examination might not be sufficient. A long-term follow-up is necessary for understanding antibody responses and its relation to clinical and epidemiological parameters. In our study, we had the unique opportunity of following the serological and clinical parameters of 626 patients (i.e. 71% of all Czech HIV-infected persons) from 1988 to 2006 (Pospı́šilová et al. 1997; Sýkora, Zástěra, and Staňková, 1992). Hence we compared the prevalence and incidence data of these patients with the situation in the general population and point out the risks of Toxoplasma infection.

A serological study of antibodies to Anaplasma phagocytophilum and Borrelia burgdorferi sensu lato in the sera of healthy individuals collected two decades apart

Sera collected from healthy individuals from the general population in the Czech Republic during repeated cross-sectional surveys were analyzed. Samples collected in the same six districts in two time periods, 1978–1989 and 2001, were compared. The study subjects were divided into six age categories between 10 and 59 years. Overall, 434 samples from 1978–1989 and 270 samples from 2001 were screened for Anaplasma phagocytophilum (AP) and Borrelia burgdorferi sensu lato (BB). The antiAP positivity rates were 13.1% and 11.5% in the first and second period, respectively, and did not differ significantly between the periods (P = 0.559). The anti-BB antibodies were detected in 33.9% and 14.8% of study subjects, respectively. The positivity rates were significantly lower in the second period (P>0.001). No considerable changes were observed in the sex distribution of positive findings between the two periods. The highest positivity rates of anti-AP antibodies were found in the 10–14 year age group: 16.0% in 1978–1989 and 16.7% in 2001. The age distribution of the anti-AP antibody positivity rates did not change substantially (P = 0.872). In 1978–1989, the lowest anti-BB antibody positivity rate (26.7%) was found in the 10–14 year age group, with a gradual increase with age to 41.1% in 50–59 year-olds. In 2001, the positivity rate in the 10–14 year age group was 26.2% and was not significantly different from that in the first period (P = 0.955). However, the positivity rates in the older age groups 15–59 years decreased significantly (P<0.001) and varied between 8.3% and 15.1%.

Bohumír Procházka, longtime CEJPH Editorial Board member, dies at 64

Biostatistician Assoc. Prof. Bohumir Prochazka, PhD, passed away on 17 August 2017 after a long illness. He dedicated his professional life to applied statistics and informatics.