In Europe, Toxoplasma gondii lineage II is dominant, and ToxoDB#1 the most frequently occurring genotype. The abundance of lineage III genotypes varies geographically and lineage I are rare, yet present in several regions of the continent. Data on the T. gondii population structure in southeastern Europe (SEE) are scarce, yet necessary to appreciate the diversity of the species in Europe. To help fill this gap, we genotyped 67 strains from nine species of intermediate hosts in Serbia by MnPCR-RFLP, determined the population structure, and identified the genotypes using ToxoDB. A neighbor-joining tree was also constructed from the isolates genotyped on nine loci. While 42% of the total genotype population consisted of ToxoDB#1 and ToxoDB#2, variant genotypes of both lineages comprised 46% of the population in wildlife and 28% in domestic animals and humans. One genotype of Africa 4 lineage was detected in a human sample. Interestingly, the findings include one lineage III variant and one II/III recombinant isolate with intercontinental distribution, which appear to be moderately related to South American genotypes. Based on these findings, SEE is a region of underappreciated T. gondii genetic diversity and possible strain exchange between Europe and Africa.

Toxoplasma gondii is an obligate intracellular parasite existing in three infectious life stages—tachyzoites, bradyzoites, and sporozoites. Rupture of tissue cysts and re-conversion of bradyzoites to tachyzoites leads to reactivated toxoplasmosis (RT) in an immunocompromised host. The aim of this study was to apply ImageJ software for analysis of T. gondii brain cysts obtained from a newly established in vivo model of RT. Mice chronically infected with T. gondii (BGD1 and BGD26 strains) were treated with cyclophosphamide and hydrocortisone (experimental group—EG) or left untreated as infection controls (ICs). RT in mice was confirmed by qPCR (PCR+); mice remaining chronically infected were PCR−. A total of 90 images of cysts were analyzed for fractal dimension (FD), lacunarity (L), diameter (D), circularity (C), and packing density (PD). Circularity was significantly higher in PCR+ compared to IC mice (p < 0.05 for BGD1, p < 0.001 for the BGD26 strain). A significant negative correlation between D and PD was observed only in IC for the BGD1 strain (ρ = −0.384, p = 0.048), while fractal parameters were stable. Significantly higher D, C, and PD and lower lacunarity, L, were noticed in the BGD1 compared to the more aggressive BGD26 strain. In conclusion, these results demonstrate the complexity of structural alterations of T. gondii cysts in an immunocompromised host and emphasize the application potential of ImageJ in the experimental models of toxoplasmosis.

Toxoplasma gondii is an obligate intracellular parasite infecting up to one third of the human population. The central event in the pathogenesis of toxoplasmosis is the conversion of tachyzoites into encysted bradyzoites. A novel approach to analyze the structure of in vivo-derived tissue cysts may be the increasingly used computational image analysis. The objective of this study was to quantify the geometrical complexity of T. gondii cysts by morphological, particle, and fractal analysis, as well as to determine if it is impacted by parasite strain, cyst age, and host type. A total of 31 images of T. gondii brain cysts of four type-2 strains (Me49, and local isolates BGD1, BGD14, and BGD26) was analyzed using ImageJ software. The parameters of interest included diameter, circularity, packing density (PD), fractal dimension (FD), and lacunarity. Although cyst diameter varied widely, its negative correlation with PD was observed. Circularity was remarkably close to 1, indicating a perfectly round shape of the cysts. PD and FD did not vary among cysts of different strains, age, and derived from mice of different genetic background. Conversely, lacunarity, which is a measure of heterogeneity, was significantly lower for BGD1 strain vs. all other strains, and higher for Me49 vs. BGD14 and BGD26, but did not differ among Me49 cysts of different age, or those derived from genetically different mice. The results indicate a highly uniform structure and occupancy of the different T. gondii tissue cysts. This study furthers the use of image analysis in describing the structural complexity of T. gondii cyst morphology, and presents the first application of fractal analysis for this purpose. The presented results show that use of a freely available software is a cost-effective approach to advance automated image scoring for T. gondii cysts.

Taenia solium is a zoonotic parasite that causes taeniasis and cysticercosis in humans (as final hosts) and cysticercosis in pigs (as intermediate hosts). The Russian Federation (RF) is traditionally considered as endemic for this zoonosis. However, the epidemiological data on T. solium infection have not been reviewed for the past 20 years, in which time dynamic economical and societal changes have occurred in the RF. The aim of this systematic review was to analyse the status of T. solium infection in RF in the 2000–2019 period. A literature search was conducted, which collected published articles, grey literature and official data on the epidemiology of T. solium taeniasis and cysticercosis in the RF published from 2000. From a total of 2021 articles and 24 official reports originally returned by the search, data were extracted from 12 full text articles and 11 official reports. Taenia solium taeniasis was continuously reported in the RF between 2000 and 2019, with a tenfold decrease in the incidence, from 0.2 per 100,000 population in 2000 to 0.023/100,000 in 2019. Also, the number of administrative units where taeniasis was detected continuously decreased. Cysticercosis in pigs had a declining trend after 2006. In conclusion, although decreasing, T. solium infection is still endemic in several regions and suspected to be endemic in most of the RF.

According to the WHO, echinococcosis is a neglected tropical disease of global importance. The Russian Federation (R.F.) is traditionally considered an endemic area of echinococcosis. This study aims to analyze the state of human infection in the R.F. in the 2000–2021 period, for which there is not enough consolidated data. Epidemiological data on human echinococcosis in the R.F. from 1 January 2000 to 31 December 2021 were collected through literature research (both published and grey literature) and official reports. From the 2022 selected records, 12 full-text articles, three doctoral dissertations, and 17 official reports were analyzed, all of which met the criteria for inclusion in the study. In the R.F., in the period from 2000 to 2021, echinococcosis (cystic (C.E.) and alveolar (A.E.) echinococcosis) has been continuously registered in humans (0.4–0.22 cases/100,000 inhabitants). Until 2013, the incidence of echinococcosis did not change (Pearson’s r (N = 13) = 0.288, p = 0.340), but in the period 2013–2021 it decreased significantly (Pearson’s r (N = 9) = −0.709, p = 0.032). In that period, the incidence of C.E. decreased significantly (Pearson’s r (N = 9) = −0.717, p = 0.035), while the incidence of A.E. did not change (Pearson’s r (N = 9) = −0.518, p = 0.154). The infection is registered annually in 30 out of 86 federal units. The C.E. infection rate was significantly higher in the European part (0.46/100,000 population) (2 = 33,783. r < 0.00001) than in the Asian part of the R.F. (0.32/100,000 population), where A.E. was more widespread. Within the European part, the frequency of C.E. infection was significantly higher in the southern (0.70/100,000 inhabitants) (χ² = 806.67, p < 00001) than in the central and northern parts (0.25/100,000 inhabitants). The incidence of C.E. per federal district was positively correlated with rural population representation (Pearson’s r (N = 8) = 0.866, p = 0.005). Every year, although in small numbers, deaths caused by echinococcosis (in the period 2009–2020—66 deaths) were registered in the R.F., significantly more often caused by A.E. than C.E. (χ² = 39.4401, p < 0.00001). Our results indicate that, between 2000 and 2021, echinococcosis was still generally endemic in the R.F. The incidence of C.E. has demonstrated a decreasing trend, especially after 2014, while the rate of A.E. remained unchanged.