ABSTRACT
The aim of this longitudinal study with 626 HIV-infected patients was to evaluate the capability of serological tests in diagnosing the presence of Toxoplasma gondii infection in HIV-infected patients, as well as the potential impact of various treatment regimes on serological results. Low IgG antibody levels and stable or declining titres predominated. IgM positivity occurred in ten patients (one seroconversion, seven latent, two cerebral toxoplasmosis). Complement fixation test (CFT) titres >or=1:32 imply that the relative risk of cerebral toxoplasmosis is 6.84 (95% confidence interval [CI] 1.44-32.5) but with a predictive value of only 14.0% (95% CI 5.3-27.9). Values of specific antibodies are not biassed by antiretroviral treatment and/or prophylaxis for toxoplasmosis, and the detection of specific antibodies is very useful in the identification of T. gondii infection in the HIV-infected population, but the role of serology in predicting the clinical manifestation of T. gondii infection is limited.
Subject(s)
Antibodies, Protozoan/blood , HIV Infections/complications , Toxoplasmosis, Cerebral/immunology , Toxoplasmosis/immunology , Adolescent , Adult , Aged , Animals , Anti-Retroviral Agents/therapeutic use , Child , Child, Preschool , Complement Fixation Tests , Enzyme-Linked Immunosorbent Assay , Female , HIV Infections/drug therapy , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Longitudinal Studies , Male , Middle Aged , Predictive Value of Tests , Toxoplasma/isolation & purification , Toxoplasmosis/complications , Toxoplasmosis/diagnosis , Toxoplasmosis/epidemiology , Toxoplasmosis, Cerebral/complications , Toxoplasmosis, Cerebral/diagnosis , Toxoplasmosis, Cerebral/epidemiologyABSTRACT
Many parasites induce specific changes in host behavior that promote the transmission of their infective stages between hosts. Toxoplasmosis in rodents is known to be accompanied by specific behavioral changes (shift in activity level, learning capacity, and novelty discrimination) that can theoretically increase the chance of infected animals being eaten by the definitive host, the cat. However, toxoplasmosis is also accompanied by many pathological symptoms. It is not known whether the behavioral changes are products of manipulation activity of the parasite or only nonspecific by-products of pathological symptoms of toxoplasmosis. Here, we compared the dynamics of development of behavioral and pathological changes in Toxoplasma gondii-infected mice. The results showed that the maximum reduction of mouse activity corresponded with the peak of pathological symptoms, and also that maximum increase of reaction times corresponded with the peak of development of tissue cysts in the brains of infected mice. Behavioral changes were only transient and disappeared before the 12th wk postinoculation. The results suggest that the behavioral changes in infected mice reported by many authors and observed in our experiments could be nonspecific by-products of pathological symptoms of toxoplasmosis rather than specific products of manipulation activity by the parasite.
Subject(s)
Behavior, Animal , Toxoplasmosis, Animal/physiopathology , Acute Disease , Analysis of Variance , Animals , Body Weight , Escape Reaction , Exploratory Behavior , Female , Health Status , Linear Models , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Motor Activity , Pain Threshold , Random Allocation , Toxoplasmosis, Animal/pathologyABSTRACT
The Win95 program for computation of distance matrixes and construction of phylogenetic or phenetic trees on the basis of RAPD, RFLP and allozyme data was presented. In contrast with other presently available software, the program FreeTree can also assess the robustness of the tree topology by bootstrap, jackknife or OTU-jackknife analysis. Moreover, the program can be used also for an analysis of data obtained in several independent experiments performed with nonidentical subsets of taxa. The function of the program was demonstrated by an analysis of RAPD data from 22 strains of Frenkelia. The program is available as an autoextractive archive containing the installation files of FreeTree and TreeView, manual in MS Word format and a sample of the input file at http://www.natur.cuni.cz/flegr/programs/+ ++freetree.
Subject(s)
Phylogeny , Random Amplified Polymorphic DNA Technique , Software , Animals , Coccidia/genetics , Eimeriida/genetics , Species Specificity , Toxoplasma/geneticsABSTRACT
The paper studies impacts of particular toxoplasmosis risk factors (consumption of raw meat and contact with cats), their interactions, and their relationship with the personality of the subjects. Among 243 men and 343 women the frequency of subjects with antitoxoplasma immunity was 26.6% and 21.6%, respectively. The association of antitoxoplasma immunity (assessed by the toxoplasmin skin test) with the two risk factors was estimated by log-linear analysis. Reported contact with cats has no influence on the probability of having antitoxoplasma immunity (P = 0.23) while the consumption of raw meat increased this probability (P = 0.0008). Very strong positive association between the contact with cats and the raw meat consumption was found among subjects without toxoplasmosis (P = 0.0028), suggesting that among these persons some subjects either incorrectly assessed their exposition to the risk factors or provided false data during the interview. The results of logistic regression suggest that the contact with cat and the consumption of raw meat are associated with particular personality traits. However, these traits differ from those associated with antitoxoplasma immunity suggesting that the correlation between antitoxoplasma immunity and consumption of raw meat reflects epidemiological importance of the raw meat rather than a correlation of both factors (raw meat consumption and probability of acquiring toxoplasmosis) with the subjects personality.
