Effect of Selected Entomopathogenic Fungal Species on Embryonic Development of Ascaris suum (Nematoda).

The aim of the study was to evaluate the potential of using five selected species of entomopathogenic fungi (Beauveria bassiana, B. brongniartii, Conidiobolus coronatus, Isaria fumosorosea, and Metarhizium robertsii) in the bioregulation of the dispersive stages of the parasitic nematode-Ascaris suum. Experimental cultures of each of the selected entomopathogenic fungi, as well as a control culture without fungi, were incubated with A. suum eggs at 26 °C for 28 days. Development of the A. suum eggs was observed using a light microscope on the 7th, 14th, 21st, and 28th days of incubation. The API-ZYM® test was used to determine, semiquantitatively, the activity of 19 hydrolytic enzymes from the entomopathogenic fungi. The cytotoxicity of the fungi was determined using tetrazole salt MTT. It was found that none of the five tested strains of entomopathogenic fungi showed an ovicidal effect, and none of them colonized the A. suum egg shells. However, ovistatic activity was observed mainly until the 14th day of incubation by I. fumosorosea, M. robertsii, and B. bassiana. In the MTT test, M. robertsii showed moderate cytotoxicity, while the other species showed low cytotoxicity. Among the strains tested, I. fumosorosea showed the highest spectrum of hydrolase production (13 out of 19 enzymes gave a positive reaction from 3 to 5; 20-40 nM or more). The absence of morphological changes in the A. suum egg shells suggests that the antagonistic effect of the studied entomopathogenic fungi may be due to their cytotoxicity, associated with the production of secondary metabolites-toxins (M. robertsii) and enzymatic activity (I. fumosorosea).

Colorectal cancer and Blastocystis sp. infection.

BACKGROUND: Blastocystis sp. is a common intestinal protozoan found worldwide. Based on gene analysis, 17 subtypes (STs, ST1-ST17) have been identified, 9 of which have been isolated from humans. Differences in clinical consequences may depend on differences among the STs. Here, we evaluated the prevalence of Blastocystis sp. in patients with colorectal cancer (CRC) compared to a control group and assessed the relationships between Blastocystis sp. infection and sex; age; and CRC grade, stage, and location. METHODS: The study included 107 CRC patients (41 women and 66 men, median age 65 years); 124 subjects without colorectal cancer or a history of oncological disease comprised the control group (55 women and 69 men, median age 63). Stool samples were collected from patients before oncological treatment and examined using light microscopy (iodine-stained smear). Additionally, PCR-based identification of Blastocystis sp. was performed in 95 stool samples from CRC patients and 76 stool samples from the control group. RESULTS: Light microscopy showed that the prevalence of Blastocystis sp. was significantly higher in CRC patients than in the control group (12.15% and 2.42%, respectively; p = 0.0041). Multivariate analysis showed that the odds of Blastocystis sp. infection were fivefold higher in the CRC group than in the control group. PCR-based molecular examinations demonstrated that the proportion of patients infected with Blastocystis sp. was significantly higher in the CRC group than in the control group (12.63% and 2.63%, respectively; p = 0.023). The predominant ST in the CRC group was ST3, detected in nine patients (75%), followed by ST1 (2 patients, 16.7%) and ST2 (1 patient, 8.3%). No association was found between Blastocystis sp. infection and age, sex, or CRC stage, grade, or location. CONCLUSIONS: The results showed that CRC was associated with an increased risk of opportunistic Blastocystis sp. infection, even before oncological treatment. To the best of our knowledge, this is the first report estimating the prevalence of Blastocystis sp. infection in CRC patients before oncological treatment in Europe.

First case of human anisakiasis in Poland.

Consumption of raw or inadequately processed marine fish may result in anisakidosis - a zoonotic disease caused by larvae of the parasitic nematodes of the family Anisakidae (anisakiasis when caused by members of the genus Anisakis (Nematoda: Anisakidae)), commonly found in a variety of marine fish species all over the world. Most cases of anisakidosis have been detected in the residents of Japan and South Korea, which results from the tradition of eating raw and semi-raw fish dishes. However, the disease is now increasingly often diagnosed in other parts of the world, including Europe (mainly in Spain and Italy). In Poland, no cases of human infection with anisakid nematodes have been detected so far. In this study, we report the first case of gastric anisakiasis in Poland, in a 59-year-old female patient, after eating raw Atlantic salmon (Salmo salar). The parasite was identified as the third-stage larva of Anisakis simplex sensu stricto on the basis of morphology and molecular analysis. The larva was still alive and causing pain until it was removed, which occurred more than 5 weeks after infection. The described case prove that anisakiasis should be considered as a potential cause of gastrointestinal tract ailments following the consumption of seafood in countries where no cases of this zoonosis have been reported to date.

Colorectal cancer and Cryptosporidium spp. infection.

Transient or constant impaired immunity is often associated with neoplastic disease or oncological treatment. Among the most common pathogens found in patients with HIV or patients undergoing chemotherapy are protozoans of the Cryptosporidium genus, which cause diarrhea in humans and animals. The present study determined the frequency of Cryptosporidium spp. infections in patients with colorectal cancer (N = 108; 42 women; 66 men; median age, 65 years), before beginning oncological treatment, compared to a control group (N = 125; 56 women, 69 men; median age, 63 years) without colorectal cancer or a history of oncological disease. We also assessed whether Cryptosporidium spp. infections were associated with age, gender, cancer stage (based on Astler-Coller or TNM classification), histological grade, or cancer location. Patients were treated at the Pomeranian Medical University, in 2009-2014. The presence of Cryptosporidium spp. antigen was determined in stool samples, analyzed with a commercial immunoenzymatic test. Cryptosporidium spp. infections occurred significantly more often (p = 0.015) in patients (13%) compared to controls (4%). The patient group showed no significant relationship between Cryptosporidium spp. infection and sex, age, tumor location, cancer grade, or stage. A multivariate logistic regression analysis adjusted for age and sex that included all subjects (patient + control groups, n = 233) showed that the odds of a Cryptosporidium spp. infection were more than three-fold higher in patients than in controls, and more than six-fold higher among men than among women. CONCLUSIONS: 1) Cryptosporidium spp. infections occurred significantly more frequently in patients with colorectal cancer (before oncological treatment) compared to controls, independent of age and sex. 2) Cryptosporidium spp. infections were not associated with the colorectal cancer stage, grade, or location or with patient age. 3) Male gender was significantly related to the frequency of Cryptosporidium spp. infections, independent of age and the presence of colorectal cancer.

The Effect of an Eextremely Low Frequency Magnetic Field on Larvae Production in the Parasite-Host System: Fasciola hepatica-Galba truncatula: a Preliminary Study.

The aim of this study was to determine the effect of an extremely low-frequency magnetic field (ELFMF) on the production of liver fluke larvae in a parasite-host system: Fasciola hepatica--Galba truncatula. Both F. hepatica eggs and F. hepatica-infected snails were exposed to an ELFMF (50 Hz, 2.0 mT) for 14 days and 36 days, respectively. F. hepatica-infected snails were divided into 4 groups, 10 specimens each. The snails of groups I and II were infected with F. hepatica larvae--miracidia obtained from control cultures, while the snails of groups III and IV were infected with miracidia reared from eggs that had been incubated in an ELFMF. After infection, the snails of groups II and IV were placed in an ELFMF, while those of groups I (control) and III were housed outside the ELFMF. At 36 days post-infection (dpi) there were no statistically significant differences between the number of F. hepatica larvae--cercariae and metacercariae, obtained from G. truncatula snails in the control group (group I) and the snail groups exposed to ELFMF (groups II, III and IV). However, a statistically significant difference between the average number of F. hepatica larvae in snail groups III and IV may indicate that the duration of exposure to ELFMF, i.e. embryogenesis period vs. the entire larval development, played a role in the production of F. hepatica larvae, and resulted in a reduction of their number.

The prevalence of Blastocystis hominis and other protozoan parasites in soldiers returning from peacekeeping missions.

Blastocystis hominis is a common intestinal parasite found in humans living in poor sanitary conditions, living in tropical and subtropical climates, exposed to infected animals, or consuming contaminated food or water. The aim of this study was to determine the prevalence of B. hominis in Polish military personnel returning from peacekeeping missions in Iraq and Afghanistan. In total, 1,826 stool samples were examined. Gastrointestinal parasites were detected in 17% of the soldiers. The examined stool samples most frequently contained vacuolar forms of B. hominis (15.3%) and cysts of Entamoeba coli (1.0%) or Giardia lamblia (0.7%). In 97.1% of stool samples from infected soldiers, we observed less than five developmental forms of B. hominis in the field of view (40×). The parasite infections in soldiers were diagnosed in the autumn and the spring. There was no statistical correlation between age and B. hominis infection. Our results show that peacekeeping missions in countries with tropical or subtropical climates could be associated with risk for parasitic diseases, including blastocystosis.

Comparison of the effect of the chosen species of saprotrophic fungi on the development of Toxocara canis and Ascaris suum eggs.

The study aim was to compare the antagonistic interaction between saprotrophic soil fungi and embryonic development of geohelminths Toxocara canis and Ascaris suum. The experimental cultures were fertilized eggs of T.canis and A. suum incubated together with mycelium of strains: Fusarium culmorum, Metarhizium anisopliae,Paecilomyces fumosoroseus, Trichoderma viride and Trichothecium roseum. In the control cultures the eggs of both nematode species were incubated without fungi. The experiment was conducted at temp. 26°C for 60 days. Compared with the control, all of the tested species of fungi significantly extended the embryonic development of both T. canis and A. suum. Most inhibitory effect on the rate of embryonic development of T. canis and A. suum had three fungal species: P. fumosoreus, M. anisopliae and T. viride. Compared with the control, on the 60th day of incubation in the presence of each of the tested fungal species, a larger percentage (p<0.05) of morphological abnormalities was stated in developing embryos of T. canis (49­69%) than in A. suum (15.1­67.7%). Among the examined fungal species, only incubation with P. fumosoroseus resulted in significantly greater (p<0.05) incidence of embryonic malformations(embryopathies) in T. canis, as compared with A. suum. Also the percentage of dead larvae of T. canis in the control and in cultures with fungi (12% and 100%, respectively) was significantly higher in comparison with A. suum (0.5% and 10.3­36%, respectively). The highest percentage of non-viable larvae of A. suum was found in the presence of P.fumosoroseus, and the lowest in the presence of M. anisopliae. Findings may indicate that T. canis eggs are more sensitive to antagonistic interaction of the examined fungal strains than A. suum eggs.

The effect of saprotrophic fungi on the development and hatching of Fasciola hepatica eggs.

The aim of this study was to determine the effect of 6 common soil fungi species: Alternaria alternata (Fr.) Keissl., Aspergillus candidus Link, Penicillium chrysogenum Thom, P. commune Thom, Trichothecium roseum (Pers.) Link and Ulocladium sp., on the hatching of miracidia, i.e., free living larvae of liver fluke (Fasciola hepatica). To this end, the eggs of F. hepatica were incubated in water in the presence of one of the aforementioned fungi species and in tap water (control) at a temperature of 26 degrees C. At the 15th day of incubation we determined the number of nonembryonated, embryonated and hatched eggs. We observed different degrees of antagonistic influences by the tested fungal strains on the development of F. hepatica eggs. Among the examined fungi, the strongest ovistatic effects were exhibited by Trichothecium roseum, Penicillium chrysogenum (R-3) and P. commune. The study showed no morphological damage to the shells of the F. hepatica eggs which may suggest a biochemical basis of antagonistic interactions by the fungi associated with the activity of fungal enzymes, mycotoxins and antibiotics. Low or no activity of peptide hydrolases in Penicillium chrysogenum and P. commune in the API ZYM test suggests their insignificant role in the degradation of shell proteins ofF. hepatica eggs.

The effects of Fasciola hepatica infection on the total antioxidant status (TAS) and the activity of proteases and their inhibitors in rat serum.

Fasciola hepatica infection results in increased production of reactive oxygen species (ROS) and changes the activity/level of antioxidants in the host organism, which leads to oxidative stress formation and oxidative modifications of lipids and proteins. Taking this into account, the aim of this study was to assess the antioxidant potential and the activity of proteases and their inhibitors in the serum of rats infected with F. hepatica. Wistar rats were infected per os with 30 metacercariae of F. hepatica. The total antioxidant status (TAS) and the activity of cathepsin G and elastase and their inhibitors (alpha1-antitrypsin and alpha2-macroglobulin) were determined at 4, 7, and 10 weeks post infection (wpi). It was confirmed that F. hepatica infection leads to a decrease in the antioxidant capacity of serum, which was manifested as a reduction in total antioxidant status by about 24, 39, and 27%, respectively, at 4, 7, and 10 wpi. At the same time, the activity of proteases increased significantly: cathepsin G by about 25, 37, and 30%, and elastase by about 18, 16, and 9% during the course of F. hepatica infection, compared with the control group. However, the activity of alpha1-antitrypsin was significantly reduced, by 36, 55, and 25%, while alpha2-macroglobulin activity was reduced by about 14, 17, and 8% during the same period of fasciolosis. These results indicate that the shift in protease/antiprotease balance towards protease action observed during the course of fasciolosis may result in a decrease in host antioxidant capacity.

Prevalence of Cryptosporidium sp. in patients with colorectal cancer.

UNLABELLED: Parasitic protozoans of the Cryptosporidium genus are intracellular intestinal parasites of mammals, causing cryptosporidiosis. Clinically, cryptosporidiosis manifests as chronic diarrhoea. Individuals with immune disorders, including those with neoplasms, are at risk of symptomatic invasion. THE AIM OF THE STUDY: Was the evaluation of Cryptosporidium sp. prevalence in patients with diagnosed colorectal cancer. MATERIAL AND METHODS: The studied group encompassed 87 patients with diagnosed colorectal cancer, undergoing surgery at the Department of General and Oncological Surgery, Pomeranian Medical University, in the years 2009-2010. Immunoenzymatic tests for Cryptosporidium sp. on faeces samples were performed with the use of commercial test kit, ProSpecT(®)Cryptosporidium Microplate Assay (Remel Inc). RESULTS: The presence of Cryptosporidium sp. was found in 12.6% of studied patients with colorectal cancer. The performed statistical analysis did not reveal any correlation between Cryptosporidium sp. infection and gender, age, neoplasm advancement stage as per Astler-Coller scale, neoplasm differentiation grade, or neoplastic tumour localisation in relation to the splenic flexure. CONCLUSIONS: There was found high prevalence of Cryptosporidium sp. in patients with colorectal cancer. It was comparable to the prevalence reported for patients with immune deficiency.

Extremely low frequency magnetic field and the hatching rate of Fasciola hepatica eggs, the fecundity and survival of liver fluke-infected snail, Lymnaea truncatula.

Eggs of Fasciola hepatica were exposed for 10 days to extremely low frequency magnetic field (ELFMF) at the frequency of 50 Hz and density of 2 mT (rms). The results show an accelerated hatching of F. hepatica eggs in relation to control (non-exposed) group. The host snails, Lymnaea truncatula, were divided into three groups; those of groups I and II were infected with the miracidia of F. hepatica hatched from control egg culture, whereas those of group III were infected with miracidia hatched from eggs affected by ELFMF. Thereafter, snails of groups II and III were exposed to ELFMF for 53 days, whereas those of group I were not exposed. At day 14 post infection, a significant decrease was observed in the number of cocoons laid by snails of group III, compared with control. Also, significant mortality in group III snails was observed 42 days post infection. The increased mortality and a lower number of cocoons laid by group III snails have probably resulted from enhanced stimulation of metacercarial parthenogenetic reproduction in consequence of infecting the molluscs with miracidia reared under ELFMF.

[Antagonistic interactions between saprotrophic fungi and geohelminths. 1. Saprotrophic fungi in the biological control of phytopathogenic geohelminths]. / Antagonistyczne interakcje miedzy grzybami saprotroficz- nymi a geohelmintami. 1. Grzyby saprotroficzne w walce biologicznej z nicieniami fitopatogenicznymi.

The state of knowledge on the possible antagonism between soil saprotrophic fungi and phytopathogenic nematodes of the genera Meloidogyne, Heterodera, and Globodera is reviewed basing on the literature and our own research. Mycelial colonisation of various developmental stages of these geohelminths is the most common factor thought to reduce their populations in nature. The following parasitic fungi can be found on the cysts, eggs, as well as the larvae of the nematodes: Paecilomyces lilacinus, Verticillium chlamydosporium, Cylindrocarpon destructans, Pochonia chlamydosporia, Fusarium spp., and Penicillium spp. The fungi invade the nematodes, such as Heterodera, Globodera, or Meloidogyne, "passively" penetrating through the natural orifices of the cysts, eggs, and larvae of the host. Equally frequent, however, is a biochemical action of the fungi prior to colonisation, which is linked with production of mycotoxirls or hydrolytic enzymes. Such an active way of fungal penetration of various stages of the phytopathogenic nematodes has been observed in Pochonia chlamydosporia, Penicillium verrucosum var. cyclopium, P. frequentans, Sclerotinia rolfsii, Rhizoctonia solani, and Fusarium spp. Triacylglycerols (TAG), phenols, as well as trichothecene, T-2, have been found in the metabolites extracted from mycelia of these species. Predation by fungi is also a factor that may reduce a population of phytopathogenic nematodes. This form of antagonism is characteristic for nematicidal fungi of the genera Arthrobotrys and Dactylella. These fungi form shrinking rings and hooks in their mycelia by which the fungus entangles and paralyses a migrating form of nematode. Despite the fact that the antagonism between fungi and nematodes is a commonly occurring phenomenon observed in the soil, the nematicidal and nematotoxic properties of fungi have not a wide application in biological plant protection. Up till now, only the bionematicides based on Arthrobotrys robusta (Royal 300 and Royal 350) as well as Paecilomyces lilacinus (Biocon and PL Plus) have found its commercial application.

[Antagonistic interactions between saprotrophic fungi and geohelminths. 2. Saprotrophic fungi in biocontrol of parasitic geohelminths of humans and animals]. / Antagonistyczne interakcje miedzy grzybami saprotroficznymi a geohelmintami. 2. Grzyby saprotroficzne w bioregulacji pasozytniczych geohelmintów czlowieka i zwierzat.

The soils ecosystem plays an important role in the epidemiology of geohelminth diseases of humans and animals. Soil contamination with ova of the parasitic geohelminths represents a global public health-hazard issue. Biological agents have been thought to control the infective forms of parasites present in the soil. Biocontrol of geohelminths represents an alternative to pesticides (i.e., nematicides), which are not efficient in killing infective nematode forms and, additionally, result in the environment pollution and long-term disturbances in the soil ecosystem homeostasis. The degree of the inhibiting effect of soil saprotrophic fungi on geohelminth embryonic development varies and depends on the species. A number of fungi cause various morphological disorders in the embryos of developing parasitic nematodes, but also have an ovicidal effect. Although the nature of the antagonism between fungi and other living organisms has not been fully explained, it is certain that mycotoxins and fungal enzymes constitute its important components. Considering the studies carried out so far, the antagonistic effect of mold fungi against the infective stages of geohelminths can be fully recommended as a real control factor, especially as these saprotrophs represent a natural factor within the soil environment, that is of particular biochemical activity.

Oxidative Modifications of Rat Liver Cell Components During Fasciola hepatica Infection.

The aim of this paper was to assess the influence of Fasciola hepatica infection on oxidative modifications of rat liver cell components such as proteins and lipids. Wistar rats were infected per os with 30 metacercariae of F. hepatica. Activities and concentrations of liver damage markers were determined in the 4th, 7th, and 10th week postinfection (wpi). A decrease in antioxidant capacity of the host liver, manifested by a decrease in total antioxidant status (TAS), was observed. Diminution of antioxidant abilities resulted in enhanced oxidative modifications of lipids and proteins. F. hepatica infection enhanced lipid peroxidation, which was visible in the statistically significant increase in the level of different lipid peroxidation products such as conjugated dienes (CDs), lipid hydroperoxides (LOOHs), malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE). The level of protein modification markers in the rat liver was also significantly changed and the most intensified changes were observed at seventh week postinfection. Concentration of carbonyl groups and dityrosine was significantly increased, whereas the level of tryptophan and sulfhydryl and amino groups was decreased. Changes in the antioxidant abilities of the liver and in the lipid and protein structure of the cell components resulted in destruction of the function of the liver. F. hepatica infection was accompanied by raising serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) as markers of liver damage. A significant decrease in lysosomal as well as in the total activity of cathepsin B during fasciolosis was also observed.

Prematurity and protracted mechanical ventilation as risk factors for Pneumocystis jiroveci infection in HIV-negative neonates in an intensive care unit.

This work was undertaken to elucidate some aspects of the epidemiology of Pneumocystis pneumonia (PP). We studied 42 mechanically ventilated, human immunodeficiency virus (HIV)-negative, severely ill neonates treated at an intensive care unit. The study group included 40 premature neonates and two mature neonates with lethal congenital defects. Progressive respiratory dysfunction in PP necessitated mechanical ventilation. Infection was usually noticeable on the 22nd day of life or after 12 days of ventilation. The usual manifestations included apnea, pallor, copious frothy sputum, seizures, and feeding difficulties. The diagnosis was established by detecting Pneumocystis jiroveci cysts in bronchial lavage fluid specimens (88.1% sensitivity). PP was managed with cotrimoxazole and pentamidine combination therapy administered over 14 days. No clinical improvement was noted in four neonates and three of them died during therapy. Prematurity and protracted mechanical ventilation are two risk factors for P. jiroveci infection in severely ill neonates in an intensive care unit.

Fasciola hepatica: effects on the antioxidative properties and lipid peroxidation of rat serum.

Fasciola hepatica infection is accompanied by increased formation of reactive oxygen species. The aim of this study was to analyze antioxidative properties of rat serum in the course of fasciolosis. Wistar rats were infected per os with 30 metacercariae of F. hepatica. Activities of antioxidant enzymes and concentrations of non-enzymatic antioxidants in serum were determined at 4, 7, and 10 weeks post-infection (wpi). Activity of superoxide dismutase (Cu, Zn-SOD) significantly decreased (by 35% during the migratory phase, by 40 and 23% at 7 and 10 wpi, respectively), while glutathione reductase activity significantly increased (by 62, 65, and 41%, at 4, 7, and 10 wpi, respectively). No significant changes were found in the activity of glutathione peroxidase. Significant decreases in concentrations of reduced glutathione, vitamins C, E, and A were observed, particularly during the migratory phase of fasciolosis (at 4 wpi). These changes were accompanied by enhancement of lipid peroxidation processes as evidenced by increased levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE). Concentrations of MDA and 4-HNE at 4 wpi increased by 38% and by 59%. MDA increased by 51% at 7 wpi and by 79% at 10 wpi, while 4-HNE increased by 87 and 118%, respectively. The results indicate that fasciolosis is associated with enhanced oxidative reactions and reduced antioxidant defense capability of rat serum.

[Pneumocystis pneumonia in newborns: a challenge in contemporary intensive care]. / Pneumocystoza noworodków - aktualne wyzwanie w intensywnej terapii.

Pneumocystis jiroveci (P. jiroveci) is the etiological agent of pneumocystis pneumonia (PCP) in immunodeficient patients. The increased interest of clinicians in this particular pathogen during the past decade was prompted by rising numbers of patients with immunosuppression caused by AIDS, chemotherapy, or organ transplantation. Premature, seriously ill infants at intensive care units constitute a potential risk group for infection with P. jiroveci. Recent advances in medical sciences, owing mainly to developments in molecular biology, permitted the verification of the taxonomic position of pathogens and contributed to a better understanding of new aspects of pathophysiology and pathogenesis of PCP. It has been demonstrated that the genus Pneumocystis represents a heterogeneous group of opportunistic fungi exhibiting narrow host specificity. Pneumocystis jiroveci is the species which is specific for humans. The present paper outlines the clinical symptoms of PCP in infants, currently used diagnostic methods, and treatment procedures in PCP.

Effect of electric power network frequency magnetic field on embryonic development of Ascaris suum (Nematoda).

Fertilised Ascaris suum eggs were subjected to an alternating electromagnetic field of frequency 50 Hz and density 2 mT for 60 days. The developing embryos in both control and experimental cultures were examined daily under a microscope. The experiment resulted in an accelerated rate of embryogenesis in the eggs incubated in the electromagnetic field, higher rates of malformed embryos as well as much higher mortality rate of L2 larvae.

Ion transport in the colon of rats experimentally infected with liver fluke (Fasciola hepatica).

The effect of liver fluke infection (Fasciola hepatica) on ion transport in the rat proximal colon was evaluated with electrophysiological methods using an Ussing apparatus. Rats were orally infected with F. hepatica metacercariae. The experimental groups of rats at 4 weeks post-infection (wpi) were in the acute stage of fasciolosis, while those at 7, 10 and 13 wpi represented the chronic phase of liver fluke infection. The control group comprised uninfected rats. The experiment consisted of recording transepithelial electrical potential difference (PD) and transepithelial electrical resistance (R) in the colon of the rats. The results revealed reduced PD levels in the colon of rats, especially during the acute phase of fasciolosis. During its chronic phase, a gradual growth in the intestinal transepithelial potential difference was found. Rat fasciolosis did not cause changes in colon sensitivity to mechanical stimulation or in the value of electrical resistance. Only at 13 wpi was resistance found to have dropped. The results have demonstrated that experimental fasciolosis leads to activation of inflammatory mediators and thus to stimulation of nerve fibres, which modifies ion transport in the epithelium of the host large intestine.

[Prevalence of Borrelia burgdorferi sensu lato in Ixodes ricinus population in forests of north-western Poland]. / Ekstensywnosc zakazenia populacji Ixodes ricinus kretkami Borrelia burgdorferi sensu lato w lasach pólnocno-zachodniej Polski.

The ticks Ixodes ricinus were collected during three growing seasons in forested areas of north-western Poland. The ticks were collected by flagging at 30 sites. The specimens collected (nymphs and adults) were subjected, after an appropiate treatment, to indirect immunofluorescence analysis (IFA). In addition, effects of temperature and atmospheric precipitation on the tick infection with the spirochaete Borrelia burgdorferi were investigated based on data supplied by the Institute of Meteorology. A total of 8519 individuals of I. ricinus were collected at the sampling sites within May-October of three consecutive years. The pool of individuals obtained consisted of 7356 nymphs, 559 females, and 604 males. The B. burgdorferri prevalence varied rather widely, from 10 to 19%. Compared to nymphs, adult individuals showed a higher infection rate. A relationship between infection rate and I. ricinus activity in different years and months was studied in detail. The boreliosis risk was found to increase with increasing tick activity. On the other hand, no correlation was found between the meteorological parameters (temperature, precipitation), tick abundance, and the B. burgdorferi infection rate.