Cellular and humoral peritoneal immunity to Mesocestoides vogae metacestode infection in mice.

BACKGROUND: Here, Mesocestoides (M.) vogae infection in mice is proposed as a suitable experimental model for studying the immunity in the peritoneal cavity of mice. METHODS: To investigate the kinetics of immune parameters in M. vogae-infected mice, we detected, using flow cytometry, the expression of selected lymphoid and myeloid markers within the peritoneal cell population at day 0, 3, 6, 10, 14, 19, 25, 30 and 35 post-infection. Then, using ELISA, we analyzed the cytokine IFN-γ, TGF-ß, IL-4 and IL-10 responses and the levels of anti-M. vogae IgG and IgM antibodies in the peritoneal lavage fluid. Cells isolated from the peritoneal cavity were subjected to further molecular analysis. To assess cell activation, peritoneal cells were exposed to LPS, and culture supernatants were collected and assayed for the level of cytokines and production of nitrite. Ly6C+ and Ly6G+ cells were isolated using MACS from the peritoneal cells at day 35 post-infection. Both MACS-isolated subsets were co-cultured with preactivated T cells to measure their suppressive capacity. Next, the role of parasite excretory-secretory antigens in induction of CD11b+ myeloid cells with the suppressive phenotype and the production of IL-10 was examined. RESULTS: In the peritoneal cavity an initial increase of CD11b+Gr-1+F4/80highMHC IIhigh cells, NK, NKT cells and CD8+ cytotoxic T cells was observed in the first week of infection. At day 14 post-infection, an increase in the number of myeloid CD11b+Gr-1+ cells was detected, and most of this cell population expressed low levels of F4/80 and MHC II in later stages of infection, suggesting the impairment of antigen-presenting cell functions, probably through the excretory-secretory molecules. Moreover, we confirmed that peritoneal Gr1+ cells (Ly6C+ and Ly6G+ population) are phenotypically and functionally consistent with myeloid-derived suppressor cells. Metacestode infection elicited high levels of IL-10 and upregulated STAT-3 in peritoneal cells. A higher level of IgM suggests that this isotype may be predominant and is involved in the host protection. CONCLUSIONS: Mesocestoides vogae tetrathyridia induced the recruitment of immunosuppressive cell subsets, which may play a key role in the downregulation of immune response in long-term parasitic diseases, and excretory-secretory antigens seem to be the main regulatory factor.

Co-administration of silymarin elevates the therapeutic effect of praziquantel through modulation of specific antibody profiles, Th1/Th2/Tregs cytokines and down-regulation of fibrogenesis in mice with Mesocestoides vogae (Cestoda) infection.

Silymarin (SIL) represents a natural mixture of polyphenols showing an array of health benefits. The present study, carried out on a model cestode infection induced by Mesocestoides vogae tetrathyridia in the ICR strain of mice, was aimed at investigating the impact of SIL as adjunct therapy on the activity of praziquantel (PZQ) in relation to parasite burden, immunity and liver fibrosis within 20 days post-therapy. In comparison with PZQ alone, co-administration of SIL and PZQ stimulated production of total IgG antibodies to somatic and excretory-secretory antigens of metacestodes and modified the expression patterns of immunogenic molecules in both antigenic preparations. The combined therapy resulted in the elevation of IFN-γ and a decline of TNF-α and TGF-ß1 in serum as compared to untreated group; however, SIL attenuated significantly the effect of PZQ on IL-4 and stimulated PZQ-suppressed phagocytosis of peritoneal macrophages. In the liver, SIL boosted the effect of PZQ on gene expression of the same cytokines in a similar way as was found in serum, except for down-regulation of PZQ-stimulated TNF-α. Compared to PZQ therapy, the infiltration of mast cells into liver after SIL co-administration was nearly abolished and correlated with suppressed activities of genes for collagen I, collagen III and α-SMA. In conclusion, co-administration of SIL modified the effects of PZQ therapy on antigenic stimulation of the immune system and modulated Th1/Th2/Tregs cytokines. In liver this was accompanied by reduced fibrosis, which correlated with significantly higher reduction of total numbers of tetrathyridia after combined therapy as compared with PZQ treatment.

Seroprevalence of Echinococcus spp. and Toxocara spp. in Invasive Non-native American Mink.

Invasive non-native species can become reservoirs of zoonotic pathogens and cause their spread during colonization, increasing the risk of zoonoses transmission to both wild hosts and humans. American mink (Neovison vison) are considered an important invasive mammal species responsible for carrying endoparasites. The aim of our study was to evaluate the role of feral American mink as a possible transmission vector of Echinococcus spp. and Toxocara spp. in wildlife. We analysed the frequency of American mink exposure to both parasites, the spatial distribution in Poland, and the variability over time on the basis of specific antibody presence using ELISA and Western blot. Alimentary tract analyses revealed that American mink do not serve as definitive hosts for these parasites. Altogether, 1100 American mink were examined. The average seropositivity for American mink was 14.2% for echinococcosis and 21.7% for toxocarosis; dual-seropositivity was detected in only 6.0%. Seroprevalence of both parasites differed between study sites and significantly increased over time in Toxocara spp. Thus, our study revealed that free-living American mink are exposed to parasites and likely to be involved in the maintenance of both Echinococcus spp. and Toxocara spp. in the wild as paratenic hosts.

Seroprevalence of Toxoplasma gondii and Neospora caninum infection in sheep, goats, and fallow deer farmed on the same area.

Toxoplasma gondii and Neospora caninum are coccidian parasites with a global distribution that cause reproductive failure and production losses in livestock. The seroprevalence of both parasite species in ruminants and Cervidae has been investigated worldwide and found to vary greatly. Studies carried out on mixed flocks with 3 ruminant species (sheep, goats, and fallow deer) living under the same conditions are excellent models for identifying any differences in the rate of infection with the 2 parasites between the animal species. Additionally, the species used in the present study differ in their feeding categories: grazers, browsers, and intermediate feeders. The aim of the study is to identify any variation in the prevalence of the 2 parasites in mixed flocks and to identify any possible relationships with food choice. The seroprevalence against T. gondii and N. caninum in 167 captive fallow deer, 64 sheep, and 39 goats were detected using commercially available ELISA. The seroprevalence for T. gondii achieved 10% in fallow deer, 21% in goats, and 47% in sheep. The seroprevalence for N. caninum achieved 13% in sheep and fallow deer and 21% in goats. Overall, 53% of the sheep, 33% of the goats, and 22% of the fallow deer were seropositive for both infections. Coinfection of T. gondii and N. caninum was detected in 6% of sheep, 8% of goats, and 2% of fallow deer. Statistical analyses of the seroprevalence levels observed between 2 parasites for each animal species revealed that only the results obtained for sheep were significant (P < 0.01). Additionally, the differences in the seroprevalence levels for T. gondii between sheep and goats and between sheep and fallow deer were statistically significant (P < 0.01). The results of the N. caninum seroprevalence levels observed among animal species were not significant. Although the variations in susceptibility to T. gondii and N. caninum infections demonstrated by the examined animals may affect the differences in seropositivity, these appear to be related to the feeding habits of the animal species. Therefore, the risk of infection by agents found close to the ground, such as coccidian oocysts, varies. Sheep as grazers are at a greater risk of infection by T. gondii than goats and fallow deer.

A Community-Based Study to Estimate the Seroprevalence of Trichinellosis and Echinococcosis in the Roma and Non-Roma Population of Slovakia.

Trichinellosis and cystic and alveolar echinococcosis are serious parasitic diseases transmissible between animals and humans. Moreover, alveolar echinococcosis is considered one of the most dangerous of human helminthoses. Roma communities are particularly numerous in Central and Eastern Europe. They are often concentrated in economically undeveloped regions and live in segregated localities with unsatisfactory housing and sanitary conditions. The study aimed to find out the seroprevalence of Trichinella and Echinococcus infections in the Roma population of segregated settlements and to compare it with the seropositivity of the non-Roma population of eastern Slovakia. Out of 823 samples, three sera showed seropositivity to Trichinella in the ELISA (Enzyme-linked immunosorbent assay) test. Subsequent Western blot reaction (WB) confirmed seropositivity in two Roma women. ELISA seropositivity to E. multilocularis was recorded in six persons (0.73%), and five (0.61%) respondents were seropositive to E. granulosus, but WB confirmed the presence of antibodies to Echinococcus spp. in one Roma participant. Positive persons suffered from unspecific clinical symptoms; Trichinella-positive persons reported headache, cough, fatigue, and muscle pain. The Echinococcus-positive participant suffered from headache and back pain. The study showed that the worse living conditions of the Roma community did not significantly influence the occurrence of Trichinella and Echinococcus infections in this minority.

First Toxoplasma gondii isolate from an aborted foetus of European bison (Bison bonasus bonasus L.).

The study was performed on a male European bison (Bison bonasus bonasus L.) foetus spontaneously aborted at the fourth or fifth month of pregnancy in the Bialowieza Forest. Serum samples from the foetus and mother revealed the presence of antibodies against T. gondii (S/P% = 88% and 75%, respectively). Mobile extracellular tachyzoites were first observed in a Vero cell culture, 110 days following inoculation of brain homogenate. PCR amplification with TGR1E1 and TGR1E2 primers confirmed the presence of T. gondii DNA, which was classified as Type I by PCR-RFLP genotyping. The sequences of 18S ribosomal RNA (18S rRNA) and 5.8S ribosomal RNA (5.8S rRNA) genes; internal transcribed spacer 1 (ITS1) and internal transcribed spacer 2 (ITS2), obtained from T. gondii isolate, have been deposited in GenBank (accession number KX459518.1). This is the first in vitro isolation and molecular identification of T. gondii from an aborted European bison foetus. The origin of this protozoan isolate indicates that the species is a significant threat to the European bison conservation program implemented in the Bialowieza Forest.

Prevalence of Toxoplasma gondii and Neospora caninum in red foxes in Slovakia.

Sera or meat juices of 177 red foxes (Vulpes vulpes) originated from the localities of a human-influenced landscape (Group 1) and 126 foxes from the protected mountain region (Group 2) of Slovakia, collected during 2010-2014 were tested for the presence of antibodies against Toxoplasma gondii using indirect ELISA and Neospora caninum by competitive ELISA. The tissue and uncoagulated blood samples were examined for the presence of the parasite's DNA. The total seropositivity to T. gondii was 62.7% (190/303) and to N. caninum 26.4% (80/303). In the Group 1 antibodies to T. gondii were detected in 74.0% (131/177) and to N. caninum in 38.9% (69/177). In the Group 2 significantly lower seropositivity of 46.8% (59/126) to T. gondii antigens (P = 0.0218) and 8.7% (11/126) to N. caninum (P = 0.0001) was detected, respectively. However, by using molecular method, the presence of both parasites, was recorded less frequently. While in Group 1 T. gondii DNA was detected in 10.0% and N. caninum DNA in 18.3% of examined samples, in Group 2 T. gondii DNA was not detected at all and N. caninum was detected in 9.1% samples only. Results indicate that examined infections are highly common in the red foxes in Slovakia and are widespread in the locations of Eastern Slovakia bordering Poland, Ukraine and Hungary. The high infection rate in foxes representing reservoir hosts, presumably originates from their infected prey, ungulate carcasses, or from residual infected tissues in the hunting grounds after evisceration of shot animals during a hunting season.

Molecular screening for bacteria and protozoa in great cormorants (Phalacrocorax carbo sinensis) nesting in Slovakia, central Europe.

This study brings the data about the occurrence of bacterial and protozoan pathogens in 32 great cormorants (Phalacrocorax carbo sinensis), representing approximately 20% of the population nesting in the surroundings of water basin Liptovská Mara (northern part of Central Slovakia). A survey revealed the presence of tick-borne bacteria Anaplasma phagocytophilum (6.25%) and parasitic protozoa Toxoplasma gondii (3.1%). These data indicate an infectious status of the great cormorant population nesting in Slovakia; they might suggest a degree of environmental contamination by infectious agents and demonstrate the role of migratory seabirds in the circulation and dispersal of pathogens with zoonotic potential.

Human Trichinella infection outbreaks in Slovakia, 1980-2008.

Trichinellosis, a parasitic zoonosis with world-wide distribution, causes serious health problems in humans and is also of economic importance. In Slovakia the most frequent species is T. britovi, causing disease mainly in wild life species. T. spiralis occurs less frequently and T. pseudospiralis only sporadically. The paper describes the epidemiology of six human Trichinella infection outbreaks recorded in Slovakia between 1980 and 2008. Before 1990 wild boar meat was the main source of infection. Later, risk farm practices, especially feeding of pigs with the wild animal´s offal contributed to the formation of synanthropic cycle and pig meat caused the epidemics in 1990, 2001 and 2008. Sausages prepared from pork and T. britovi infected dog meat and offered as a local food specialty on traditional folk festival in 1998 (Brezno district, Central Slovakia) were the source of the largest human outbreak recorded in Slovakia. The anti-Trichinella antibodies were detected in 336 event visitors. The main reason of repeated human epidemics in Slovakia has been the permanent circulation of Trichinella spp. in sylvatic cycle, especially in red foxes and wild boars. High population density of both animal species, persistent prevalence of trichinellosis in wild boars and even increasing positivity of red foxes suggest that the risk of human outbreaks in Slovakia persists.

Wild boar (Sus scrofa) - reservoir host of Toxoplasma gondii, Neospora caninum and Anaplasma phagocytophilum in Slovakia.

In Central Europe the wild boar population is permanently growing and consequently Cf foodborne infections. In this study serological and molecular detection of Toxoplasma gondii and Neospora caninum in wild boars was evaluated. Moreover, same samples were screened for the presence and genetic variability of tick-borne bacterium Anaplasma phagocytophilum. Blood samples collected from 113 wild boars from Southern Slovakia were examined for antibodies to T. gondii by indirect and to N. caninum by competitive ELISA. The presence of parasitic DNA in blood samples was determined by standard or real time PCR techniques. Antibodies against T. gondii and N. caninum were detected in 45 (39.8%) and 38 (33.6%) animals, respectively. Females were more frequently infected for both pathogens than males. The high seropositivity against both coccidia indicates a permanent occurrence of these pathogens in the studied locality. T. gondii DNA was confirmed in five seropositive boars (4.4%) and N. caninum in 23 blood samples (20.4%). Three out of 23 N. caninum PCR positive animals did not show seropositivity. Three out of 113 blood samples of wild boars were positive for A. phagocytophilum (2.7%). The obtained A. phagocytophilum sequences were 100% identical with GenBankTM isolates from Slovak dog (KC985242); German horse (JF893938) or wild boar (EF143810) and red deer (EF143808) from Poland. Coinfections of T. gondii with N. caninum and N. caninum with A. phagocytophilum were detected in single cases. Results suggest a potential zoonotic risk of toxoplasmosis transmission to humans and the spread of neosporosis to farm animals.

Immunodiagnostic approaches for the detection of human toxocarosis.

Human toxocarosis is an important zoonosis caused by larvae of Toxocara canis/cati. The objective was to evaluate the role of IgG anti-Toxocara antibody detection and the specific IgG avidity in diagnostics of human toxocarosis. Anti-Toxocara IgG antibodies and IgG avidity were evaluated by excretory-secretory (ES)-enzyme-linked immunosorbent assay (ELISA). The IgG anti-Toxocara seroprevalence in people (n = 7678) from western Slovakia was 15.3% and found to be highest in the oldest age groups. The presence of low- IgG avidity in 179 suspected patients for toxocarosis was evaluated in relation to sex, age, IgG antibody levels, eosinophilia, increased total IgE, domicile, geophagia, dog/cat ownership, anamnesis. Low- IgG avidity index was found in 30.7% of the patients. The low- IgG avidity in eosinophilic group (42.1%) was significantly higher than in non-eosinophilic group (22.0%; P = 0.043). Substantially higher eosinophilia was detected in children (under 10 years old; 55.6%) than in adults (aged ≥ 41 years; 17.6%; P = 0.009). Significant difference between seroprevalence of total IgE in patients coming from towns (48.8%) and patients from villages (21.3%) was established (P = 0.007). Mild negative correlation (r = -0.477, P = 0.043) was observed between the amounts of eosinophils and the values of IgG avidity. The sensitivity and specificity of IgG avidity assay were 43.8% and 83.3%, respectively. Our results suggest that besides anti-Toxocara IgG, measurement of IgG avidity may be useful for the determination of acute toxocarosis. Moreover, these tests should be accompanied by other immunological markers and determinants of examined patients such as eosinophilia, increased total IgE and age.

Neospora caninum - Associated Abortions in Slovak Dairy Farm.

BACKGROUND: Neospora caninum is considered one of the major causes of repeated abortions in livestock. This study aimed to determine the seropositivity to N. caninum using indirect ELISA and the influence of the infection on the occurrence of abortions in selected dairy herd in Slovakia. METHOD: Blood samples were obtained from 490 cattle over a period of two years and were tested for N. caninum antibodies using indirect ELISA. RESULTS: The presence of specific antibodies in the herd was detected in 118 (24.1%) cows. According to selected groups; 117 (41.0%) cows with a history of abortion, 65 (43.3%) heifers and 223 (2.2%) cows without abortions were tested positive to Neospora. Vertical transmission of N. caninum dominated in examined herd and the relative risk (RR) of dam-daughter seropositivity in progenies of seropositive mothers was 2.1 times higher than in progenies of seronegative dams. Molecular analyses of aborted foetuses of seropositive mothers showed the presence of Neospora DNA. However, 23 (28.1%) of heifers born to seronegative cows were seropositive, indicating also the postnatal transmission of the infection from the environment. CONCLUSION: Study revealed significant correlation between the presence of specific antibodies and the occurrence of abortions, the risk of abortion in seropositive animals was 3.8 times higher than in seronegative ones. Incorrect farm management contributed to spread and circulation of neosporosis in entire dairy herd what could significantly impair the reproduction and economic parameters of breeding.

Evaluation of purified antigen fraction in the immunodiagnosis of cystic echinococcosis.

Echinococcus granulosus antigen B fraction (AgB) was evaluated for its prognostic value in the serological follow-up of cystic echinococcosis (CE), compared to crude hydatid fluid (HF) as well as soluble somatic Echinococcus multilocularis antigen (Em). The sensitivity and specificity of enzyme-linked immunosorbent assays (ELISA) were compared examining 177 sera from patients with different clinical courses and outcome of CE and with other parasitic infections. AgB-ELISA in comparison to confirmed cystic echinococcosis has 96.4% sensitivity and 97.2% specificity, with 93.1% positive predictive value and 98.6% negative predictive value. The HF-ELISA was more sensitive than the AgB-ELISA, but its specificity was lower. Our results indicate that AgB-ELISA was more satisfactory for seroconfirmation of acute echinococcosis than HF-ELISA. Moreover, the AgB-ELISA has a potential key role in control measures implemented in patients undergoing surgery. In sera of patients more than 3 months after the treatment, no antibody response to antigen B was detected; however, with conventionally used HF-ELISA, they were still positive. The AgB is recommended for the confirmatory diagnosis. AgB-WB allocated low background with typical "triplet" bands at 8-12-16 kDa.

Detection of antibodies to Neospora caninum in moose (Alces alces): the first report in Europe.

Neospora caninum Dubey, Carpenter, Speer, Topper et Uggla, 1988 is a protozoan parasite originally reported as a major cause of bovine abortions worldwide. It is documented that the parasite is widely spread among non-carnivorous cervids. The purpose of this study was to investigate the seroprevalence of N. caninum in moose (Alces alces Linnaeus). Blood samples collected in 2010 and 2012 in the northeastern Poland were tested for antibodies to N. caninum by agglutination test (NAT), a commercial competitive screening enzyme-linked immunosorbent assay (cELISA) and enzyme-linked immunoassay (ELISA). Sera that gave a positive result were further investigated by western blot (WB) analysis to verify the presence of antibodies. Antibodies to N. caninum were detected in one of seven moose. The antibody titer was confirmed by NAT (1 : 1 280), cELISA (I = 91%) and ELISA (OD = 0.736). The main immunodominant antigens detected by WB were 120, 70, 55, 35 and 16 kDa proteins. This is the first evidence of N. caninum seropositivity in moose living in a natural environment in Europe.

Kinetics of anti-Neospora antibodies during the period of two consecutive pregnancies in chronically infected dairy cows.

The course of anti-Neospora antibody kinetics during two consecutive pregnancies has been evaluated in five chronically infected dairy cows. The blood samples of cows were collected monthly. Anti-Neospora antibodies in blood sera were detected by indirect ELISA (ID-VET, France). During whole period of the study cows remained seropositive; with S/P% values (iELISA) ranging from 94 to 214%. The antibody kinetics determined by iELISA showed a significant increase (P<0.0059) of specific IgG antibodies in the third trimester of both pregnancies. The monitored cows gave birth to 10 healthy calves (4 steers and 6 heifers). To confirm the occurrence of vertical transmission of Neospora from mothers to offspring in the herd, dam-daughter serology was performed. Anti-Neospora antibodies was found in 4 from 6 heifers (>6 months old). Study presents original data reporting on the very similar persistent pattern of anti-Neospora antibody levels during the third trimester of pregnancies in all five dairies. Based on the high seropositivity of female offspring, the reactivation of a latent infection of cows rather than a re-infection can be supposed.

Toxoplasma gondii, Neospora caninum and tick-transmitted bacterium Anaplasma phagocytophilum infections in one selected goat farm in Slovakia.

Parasitic diseases of livestock together with poor welfare conditions can negatively affect the health status and production of small ruminants. Protozoan parasites and tick-borne infectious agents are common threat of livestock including small ruminants mostly during the pasture season. Therefore the priority of the study was to analyse the circulation and presence of two protozoan parasites Toxoplasma gondii and Neospora caninum as well as tick-transmitted bacterium Anaplasma phagocytophilum in one selected goat farm in Eastern Slovakia. Throughout a three-year study period we have repeatedly screened the sera and blood of goats and dogs from monitored farm. In total, 343 blood serum samples from 116 goats were examined by ELISA. The mean seropositivity for T. gondii was 56.9% (66/116, CI (95%) = 48-66.0) and 15.5% (18/116, CI (95%) = 9.3-22.7) for N. caninum. The permanent occurrence of anti-Toxoplasma and anti-Neospora antibodies was detected in repeatedly examined goats during the whole monitored period. The presence of both parasites in the flock was analysed by PCR. DNA of T. gondii was confirmed in 12 out of 25 Toxoplasma-seropositive goats and N. caninum in 14 samples out of 18 Neospora-seropositive animals; four goats were co-infected with both pathogens. The risk of endogenous transmission of both parasites was pursued by examination of 41 kid's sera, where seropositivity for toxoplasmosis was 31.7% and for neosporosis 14.6%. In dogs 61.1% seropositivity for T. gondii and 38.9% for N. caninum was found, however, their faeces were negative for coccidian oocysts. Eight out of 108 tested animals were infected with A. phagocytophilum, the causative agent of tick-borne fever. Seven of them were simultaneously infected with T. gondii and A. phagocytophilum, out of which four goats were concurrently infected with all three pathogens.

Occurrence and genetic characterization of Toxoplasma gondii in naturally infected pigs.

The protozoan Toxoplasma gondii is an obligate intracellular parasite that infects a wide range of warm-blooded vertebrates. The data about the occurrence of toxoplasmosis in slaughter pigs in the Slovak Republic are still missing. The aim of our study was to estimate the prevalence of toxoplasmosis in pigs from Slovakia during the period of 2006-2010 by ELISA and PCR methods. In sera of 970 slaughter pigs, 2.16% seropositivity to T. gondii was detected. In tissue samples of seropositive pigs the presence of T. gondii DNA was confirmed. In six monitored Slovak regions the seropositivity varied between 1.11 and 3.48%. The statistically significant differences were recorded between the Kosice and Presov region. The seroprevalence of toxoplasmosis in sows (4.26%) was two times higher than that in slaughter pigs (2.06%) (OR = 2.12; 95% CI = 0.48-9.36). Presence of Toxoplasma gondii in tissues of seropositive pig isolates was confirmed by TGR1E and B1 genes and analysis of DNA polymorphism at SAG2 and ROP1 genes revealed the presence of virulent strain of genotype I in 85.7% of infected pigs and an avirulent strain (genotype II) in 14.3% of pigs.

Seroprevalence of Toxoplasma gondii in wild boars (Sus scrofa) in the Slovak Republic.

Toxoplasma gondii is a protozoan parasite of great medical and veterinary importance. The aim of this study was to determine the seroprevalence of toxoplasmosis in wild boars hunted in the Slovak Republic in 2003. Examination of 320 wild boars revealed a seroprevalence of 8.1%. The majority of seropositive wild boars came from the north-western and southern regions of Slovakia. This study indicates that T. gondii infection is common in wild boars in the Slovak Republic, underlines its zoonotic potential and the importance of high standards of hygiene during the handling of game.

Climate and environmental factors influencing Echinococcus multilocularis occurrence in the Slovak Republic.

During the period of 2000-2004, 3,096 red foxes from the whole territory of the Slovak Republic were sampled and examined parasitologically for infections with Echinococcus multilocularis, causative agent of serious alveolar echinococcosis in humans. Relations between prevalence of the parasite in individual regions of Slovakia and some environmental factors were weighted. During the study period, great differences of prevalence and infection intensity were found on a regional level and significant between-year fluctuation of both parameters was observed. High-endemic foci with an estimated prevalence of more than 30 % were detected in the northern and central part of the country. Climatic conditions, including low mean annual air temperature, high mean annual rainfall and the high humidity of the soil, showed to be important for E. multilocularis distribution. Significant correlation was calculated between prevalence of the tapeworm, mean annual precipitation values, and population density of small mammals.