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Human pediculosis is a parasitic disease caused by Pediculus humanus. The infection occurs mainly among children aged 5 to 13 years old. Due to the high prevalence of Pediculus humanus in the environment and the parasite's ability to transmit pathogenic bacteria, the disease needs monitoring. Each year, nearly 12 million patients suffer from head lice infestation. Current recommended treatment includes topical antiparasitic agents, oral therapy, and combing. The infestation causes potential social side effects such as embarrassment, discomfort, and necessary absenteeism from school or kindergartens. Various types of restrictions were used in Poland during the COVID-19 pandemic since 2020, including restrictions on interpersonal contacts, social isolation and functional restrictions on educational facilities. The aim of this study was to evaluate the relationship between COVID-19 pandemic and the prevalence of head lice among children attending schools and kindergartens in Poland. The study group consisted of children aged 3 to 14 years old attending elementary school and kindergartens. A total of 5008 children were examined in educational institutions by registered nurses in period of 35 months. The results indicated that the restrictions applied during the COVID-19 pandemic reduced significantly the number of infected school children comparing to the pre-pandemic state. At the same time, restrictions and functional limitations of educational facilities did not significantly affect the incidence of head lice among preschool children. It can be concluded that restrictions on direct human contacts also significantly reduced the incidence of human head lice infestation among the study population.

Background Free-living amoebae of the genus Acanthamoeba are cosmopolitan, widely distributed protozoans that cause a severe, vision-threatening corneal infection known as Acanthamoeba keratitis (AK). The majority of the increasing number of AK cases are associated with contact lens use. Appropriate eye hygiene and effective contact lens disinfection are crucial in the prevention of AK because of the lack of effective therapies against it. Currently available multipurpose contact lens disinfection systems are not fully effective against Acanthamoeba trophozoites and cysts. There is an urgent need to increase the disinfecting activity of these systems to prevent AK infections. Synthesized nanoparticles (NPs) have been recently studied and proposed as a new generation of anti-microbial agents. It is also known that some plant metabolites, including tannins, have anti-parasitic activity. The aim of this study was to evaluate the anti-amoebic activity and cytotoxicity of tannic acid-modified silver NPs (AgTANPs) conjugated with selected multipurpose contact lens solutions. Methods The anti-amoebic activities of pure contact lens care solutions, and NPs conjugated with contact lens care solutions, were examined in vitro by a colorimetric assay based on the oxido-reduction of alamarBlue. The cytotoxicity assays were performed using a fibroblast HS-5 (ATCC CRL-11882) cell line. The results were statistically analysed by ANOVA and Student-Newman-Keuls test using P < 0.05 as the level of statistical significance. Results We show that the NPs enhance the anti-Acanthamoeba activities of the tested contact lens solutions without increasing their cytotoxicity profiles. The activities are enhanced within the minimal disinfection time recommended by the manufacturers. Conclusions The conjugation of the selected contact lens solutions with AgTANPs might be a novel and promising approach for the prevention of AK infections among contact lens users. Graphical Abstract

Background: Free living amoebae of the genus Acanthamoeba are cosmopolitan, widely distributed protozoans causing a severe, vision-threatening corneal infection known as Acanthamoeba keratitis (AK). The majority of the increasing number of AK cases are associated with contact lenses use. Appropriate eye hygiene and effective contact lenses disinfection are crucial in prevention of this infection because of the lack of effective therapies against AK. Currently available multipurpose contact lens disinfection systems are not fully effective against Acanthamoeba trophozoites and cysts. There is an urgent need to increase the disinfecting activity of these systems to prevent Acanthamoeba keratitis infections. Synthesized nanoparticles have been recently studied and proposed as a new generation of anti-microbial agents. It is also known that plant metabolites, including tannins, present anti-parasitic activity. The aim of this study was to evaluate the anti-amoebic activity and cytotoxicity of the tannic acid-modified silver nanoparticles (AgTANPs) conjugated with the selected multipurpose contact lens solutions.Methods: The anti-amoebic activity of pure contact lens care solutions and nanoparticles conjugated with contact lens care solutions were examined in vitro by a colorimetric assay, based on the oxido-reduction of AlamarBlue. The cytotoxicity assays were performed using a fibroblast HS-5 (ATCC CRL-11882) cell line. The results were statistically analyzed by ANOVA and Student-Newman-Keuls tests using the P < 0.05 level of a statistical significance.Results: We show that nanoparticles enhanced anti-Acanthamoeba activity of the tested contact lens solutions without increasing their cytotoxicity profile. The activity is enhanced within the minimal disinfection time recommended by the manufacturer.Conclusions: The conjugation of the selected contact lens solutions with AgTANPs might be a novel and promising approach as a part of preventive actions of Acanthamoeba keratitis infections among contact lens users.

Background: Free living amoebae of Acanthamoeba genus are cosmopolitan, widely distributed protozoans causing severe, vision-threatening corneal infection known as Acanthamoeba keratitis (AK). Majority of the increasing number of AK cases are associated with contact lenses use. Due to lack of effective therapies against AK, proper eye hygiene and effective contact lenses disinfection are crucial in prevention of this infection. Currently available multipurpose contact lens disinfection systems are not fully effective against Acanthamoeba trophozoites and cysts. There is an urgent need to increase the disinfecting activity of these systems to prevent Acanthamoeba keratitis infections. Synthesized nanoparticles have been recently studied and proposed as a new generation of anti-microbial agents. It is also known that plant metabolites, including tannins, present anti-parasitic activity. The aim of this study was to evaluate the anti-amoebic activity and cytotoxicity of the tannic acid-modified silver nanoparticles (AgTANPs) conjugated with selected multipurpose contact lens solutions. Methods: The anti-amoebic activity of pure contact lens care solutions and nanoparticles conjugated with contact lens care solutions were examined in vitro by colorimetric assay, based on the oxido-reduction of AlamarBlue. The cytotoxicity assays were performed using a fibroblast HS-5 (ATCC CRL-11882) cell line. Results were statistically analyzed by ANOVA and Student-Newman-Keuls tests using the p

Introduction Various Acanthamoeba species are free-living organisms widely distributed in the human environment. Amphizoic amoebae as facultative parasites may cause vision-threatening eye disease – Acanthamoeba keratitis, mostly among contact lens wearers. As the number of cases is increasing, and applied therapy often unsuccessful, proper hygienic measures and effective contact lenses disinfection are crucial for the prevention of this disease. Available contact lens solutions are not fully effective against amphizoic amoebae; there is a need to enhance their disinfecting activity to prevent amoebic infections. The use of developing nanotechnology methods already applied with success in the prevention, diagnostic and therapy of other infectious diseases might be helpful regarding amoebic keratitis. This study assesses the in vitro effect of selected contact lens solutions conjugated with nanoparticles against Acanthamoeba trophozoites. Material and methods Three selected contact lens solutions conjugated with silver and gold nanoparticles in concentration of 0.25–2.5 ppm were used in vitro against the axenically cultured ATCC 30010 type Acanthamoeba castellanii strain. The anti-amoebic efficacy was examined based on the oxido-reduction of AlamarBlue. The cytotoxicity tests based on the measurement of lactate dehydrogenase (LDH) activity were performed using a fibroblast HS-5 cell line. Results Enhancement of the anti-amoebic activity of contact lens solutions conjugated with selected nanoparticles expressed in the dose dependent amoebic growth inhibition with a low cytotoxicity profile was observed. Conclusions Results of the study showed that conjugation of selected contact lens solutions with silver nanoparticles might be a promising approach to prevent Acanthamoeba keratitis among contact lens users.

Introduction The protozoan Trichomonas tenax is considered to be a human specific flagellate of the oral cavity, found in humans with poor oral hygiene and advanced periodontal disease. Morphological variability and great similarity between species occurring in humans and animals, complicate the specific identification of trichomonads, using microscopic examination and other standard parasitological techniques. Objective The aim of the study was to search for and identify T. tenax in domesticated animals using molecular methods. The obtained data were assessed in terms of potential effects of a spread of the species deriving from the animals in the human environment. Material and methods 301 animals: 142 dogs, 57 cats and 102 horses, were examined in terms of their mouth status and occurrence of trichomonads. ITS1–5.8S rRNA-ITS2 region was amplified and sequenced. Results Finally, 7 dogs, 3 cats and 1 horse were diagnosed positive for T. tenax by PCR. In the oral cavity of 9 /11 animals, gingivitis and dental plaque accumulation were diagnosed. 9 /11 sequences of trichomonad isolates showed 100% identity with T. tenax sequence derived from the GenBank. The sequences of 2 isolates differed by substitutions. Conclusions It was proved that T. tenax , considered so far as a human specific parasite, can also inhabit the oral cavity of dog, cat and horse. To summarize, T. tenax was detected in the mouths of different domesticated animals, indicating that in Poland it can colonize a wider range of hosts than previously known. The owners of 3 dogs showed oral tissue inflammation of different intensity and were also positive for T. tenax ; therefore, oral trichomonosis spread from humans to domestic animals and conversely should be taken into consideration.

Acanthamoeba keratitis, the vision-threatening corneal disease reported with increasing frequency in Poland is difficult to treat due to extremely high resistance of the amoeba cysts to chemicals. The agents of possible anti-amoebic activity are still tested. Pathogenic Acanthamoeba samples/isolates acquired from severe cases of keratitis examined by molecular techniques to determine genotypes, compared to one another as well as to the environmental Acanthamoeba castellanii Neff strain were included in the studies. These strains were in vitro examined in terms of their sensitivity/resistance to selected chemicals and tolerance to temperature changes. Samples of the strains cultivated in vitro under bacteria-free conditions were monitored during different growth phases. Higher amoebic population dynamics was observed in both pathogenic Acanthamoeba strains during transfer to 37°C. Agents tested influenced population dynamics in different degree; they showed amoebostatic or amoebicidal effects, however a tendency toward induction of encystment also appeared. Because activation of the dormant cysts can lead to repeated development of amoebae, very important is cysticidal efficacy of chemicals. Further in vitro investigations on various Acanthamoeba strains with different chemicals are still necessary.

Introduction and objective This study presents the results of comparative investigations aimed to determine microbiota that can occur in the oral environment in different human populations. The objective of the research was to identify pathogenic oral microbiota, the potential cause of health complications in patients of different population groups. Materials and method The study included 95 patients requiring dental or surgical treatment; their oral cavity environment microbiota as risk factors of local and general infections were assessed. Results In clinical assessment, differences occurred in oral cavity conditions between patients with malformations of the masticatory system, kidney allograft recipients and individuals without indications for surgical procedures. The presence of various pathogenic and opportunistic bacterial strains in oral cavities were revealed by direct microscopic and in vitro culture techniques. Conclusions Colonization of oral cavities of patients requiring surgical treatment by the potentially pathogenic bacteria constitutes the threat of their spread, and development of general infections. Assessment of oral cavity infectious microbiota should be performed as a preventive measure against peri-surgical complications.

In this study five cases of suspected alveolar echinococcosis from Poland in which surgical treatment was needed, previously diagnosed by means of imaging and serological techniques, were analyzed in terms to identify the causative agent. Samples of the parasite tissues taken perioperatively from the liver lesions were used for the histopathological and molecular examinations. The sequences of all isolates were identical to Echinococcus multilocularis; all nad1 sequences have been deposited in GenBank The histopathological examination revealed Passpositive fragments of laminated layers typical for E. multilocularis metacestode. Obtained results confirm that the use of imaging techniques only may be insufficient to diagnose alveococcosis thus the recognition of the zoonosis should base on several procedures; especially valuable are highly sensitive and specific molecular methods.

Acanthamoeba species are ubiquitous in natural and man-made environments worldwide; some strains are able to colonize human eyes as facultative parasites. It has been shown that environmental and clinical isolates/species of Acanthamoeba vary in their pathogenicity. In this study we examine and compare the in vitro effects of the changing temperature on the population dynamics of subsequent amoebic strains. Identification of Acanthamoeba strain by morphological and molecular methods and temperature assays were performed. Monitoring of the corneal and environmental strains showed changes in population densities and a termo-tolerance correlating with pathogenicity of amoebae. Comparative assessment of results indicated differences in viability of amoebic populations in exponential growth phase in vitro cultivation. The increased awareness of the threat is needed for better understanding of impact of factors examined on pathogenesis in human infected with Acanthamoeba strains.

Small amoebae belonging to the Acanthamoeba genus complete their life cycles in different environmental niches as free-living protists however some of them are facultative parasites that can cause severe disease in humans. The sight-threatening Acanthamoeba keratitis develops in immune-competent persons, mainly in contact lens wearers; it is detected with increasing frequency along with the spread of contact lens use. The high abundance of the amoebae in the environment is important for dispersion and transmission of the infections among humans. Emerging threats for the public health generated by these amoebae is the serious medical problem worldwide. Nonspecific symptoms, similar to those occurring in the other eye diseases, diagnostic mistakes, the delay of an appropriate treatment, an exceptional high resistance of the amoebae to chemicals and drugs result in a prolonged course of the disease and often unsuccessful therapeutic management. Thus, different chemicals are still examined for their potential activity in vitro against various species, strains/isolates of Acanthamoeba. As the prolonged therapy often induces encystation subsequently leading to excystment and recurrences of amoebic keratitis, apart from anti-amoebic activity, cysticidal effect of examined agents is desirable. In the present study, results of our comparative investigations showed that cationic antiseptic chlorhexidine digluconate indicated in vitro anti-amoebic effect on environmental Acanthamoeba castellanii Neff strain and pathogenic corneal Acanthamoeba polyphaga T4 genotype. Amoebostatic effect of the disinfectant was expressed in reduced number of surviving amoebae in comparison to the respective control cultures; simultaneously, despite prolonged incubation with the agent no stimulation of encystation was noted. The corneal strain was more resistant to the tested compound than the Neff strain. The cysticidal efficacy of chemicals is very expected, thus further in vitro studies on pathogenic Acanthamoeba strains with different application chemicals pattern are needed.

Free-living amoebae belonging to Acanthamoeba genus are widely distributed protozoans which are able to cause infection in humans and other animals such as keratitis and encephalitis. Acanthamoeba keratitis is a vision-threatening corneal infection with currently no available fully effective treatment. Moreover, the available therapeutic options are insufficient and are very toxic to the eye. Therefore, there is an urgent need for the development of more effective anti-amoebic agents. Nanotechnology approaches have been recently reported to be useful for the elucidation antimicrobial, antiviral, antifungal and antiprotozoal activities and thus, they could be a good approach for the development of anti-Acanthamoeba agents. Therefore, this study was aimed to explore the activity and cytotoxicity of tannic acid-modified silver nanoparticles, pure silver nanoparticles and pure gold nanoparticles against clinical strains of Acanthamoeba spp. The obtained results showed a significant anti-amoebic effect of the tannic acid-modified silver nanoparticles which also presented low cytotoxicity. Moreover, tannic acid-modified silver nanoparticles were well absorbed by the trophozoites and did not induce encystation. On the other hand, pure silver nanoparticles were only slightly active against the trophozoite stage and pure gold nanoparticles did not show any activity. In conclusion and based on the observed results, silver nanoparticle conjugation with tannic acid may be considered as potential agent against Acanthamoeba spp.

Amphizoic amoebae belonging to the genus Acanthamoeba are known as etiological agents of sight-threatening Acanthamoeba keratitis. The leading risk factor for the development of this serious human disease is contact lens wearing which popularity increases worldwide, also in Poland. The disease with active epithelial inflammations, corneal ulcers, including loss of the visual acuity is a serious medical problem as an emerging threat for the public health related to improper contact lens hygiene. The treatment of the amoebic keratitis is difficult, often unsuccessful due to delayed proper diagnosis. The clinical picture of the disease, often with severe course is nonspecific, similar to that occurring in viral, fungal or bacterial keratitis, thus clinical symptoms alone are not sufficient to identify the causative agent of the amoebic infection. Early diagnosis is decisive for the suitable therapeutic management and the treatment efficacy. In our studies, several complicated, difficult to treat Acanthamoeba keratitis incidences pertaining Polish patients using contact lenses have been retrospectively analyzed in terms of the usefulness of non-invasive methods of in vivo confocal microscopy and in vitro culture techniques applied for diagnosis. Hyper-reflective double-walled spherical Acanthamoeba cysts, with a more reflective outer wall were detected in the epithelium and anterior layers of the corneal stroma. In vivo confocal microscopy, if available, may be a valuable, sensitive tool for diagnosis in late identified severe infections mainly with strong viability strains, however confoscan may offer limited value at lowintensity amoebic infections. The microscopic visualization of amoebae in slides prepared directly from corneal scraping and laboratory examinations of specimens from in vitro cultivated corneal isolates allow to confirm or verify results of in vivo examinations, furthermore to identify directly the pathogens and to clarify previous misdiagnoses.

Different Acanthamoeba species are amphizoic organisms distributed in wide range of habitats in natural and man-made environments; they are also detected on surfaces of equipment and accessories in health facilities. Some strains of the amoebae are causative agents of the vision-threatening human disease Acanthamoeba keratitis, mainly reported in contact lens wearers. An exceptional high resistance of Acanthamoeba trophozoites and particularly cysts to chemicals, disinfectants and drugs is believed as influencing difficulty resulting in unsuccessful therapeutic management. As Acanthamoeba keratitis is the serious medical problem worldwide, different chemicals with possible activity against environmental and clinical Acanthamoeba strains are tested. In our study, selected disinfectants used in health care settings and laboratories were tested and their efficacy against the corneal strains Acanthamoeba castellanii and A. polyphaga , and environmental A. castellanii Neff strain was assessed. Comparative assessment of results of the assays show that, apart from amoebistatic effects, the disinfectants indicated expected cysticidal efficacy.

Free-living, cosmopolitan amoebae of the Acanthamoeba genus may be the causative agents of Acanthamoeba keratitis (AK) – a progressive, vision-threatening infection of the human cornea described particularly among contact lens wearers. Use of contact lens care solutions, effective against these organisms, is important in preventing AK infections. 3 different strains of Acanthamoeba castellanii of the T4 genotype (Neff strain and two others, isolated from patients with AK) were exposed to 4 selected multipurpose contact lens care solutions available in Poland: Ciba Vision AoSept Plus, Bausch & Lomb ReNu MultiPlus, Alcon Opti-Free, Ciba Vision Solo Care Aqua. No amoebicidal effect was observed. The strongest amoebostatic effect was visible after 24 h of exposition to Opti-Free and ReNu solution and associated with percentage increase of rounded, motionless forms. This is significantly longer than minimum disinfection time recommended by manufacturers of all tested multipurpose solutions. Surprisingly, no clear induction of the encystation process was observed.

Recently, incidents of Acanthamoeba keratitis, the vision-threatening eye disease, are reported with increasing frequency worldwide, particularly in contact lens wearers. In our study, the retrospective assessment of in vitro dynamics of subsequent pathogenic Acanthamoeba isolates cultured at 24°C, detected in Polish contact lens wearers with keratitis is presented and results compared with those of environmental A. castellanii Neff strain. There were delayed the proper diagnosis that influenced prolonged and severe course of this eye disease and treatment difficulties. The corneal material was examined directly to visualize developmental amoeba stages for diagnose verification, microbiologically tested for the specific identification of bacteriae and fungi, and in vitro grown in culture medium in temperature 24°C. Among twenty-six keratitis incidents analyzed, eleven were cases of Acanthamoeba keratitis; in the six of them, Acanthamoeba strains and concomitant bacterial and/or fungal infectious agents were detected. In vitro assays showed variability in population density of several clinical strains in the exponential growth phase expressed in various range of overall amoeba number and different proportion between trophozoites and cysts. The clear influence of temperature on the in vitro cultivation of the amoebae was observed: statistically significant lower population dynamics was revealed by most of pathogenic clinical isolates in comparison with those showed by environmental strain. The in vitro monitoring of dynamics of Acanthamoeba strains isolated from infected eyes may be helpful for diagnostics verification, especially in mixed infectious keratitis.

The oral cavity environment may be colonized by polymicrobial communities with complex, poorly known interrelations. The aim of this study was to determine oral microbiota diversity in order to prevent the spread of infectious microorganisms that are risk factors for human health complications in patients requiring treatment due to various disabilities. The study examined Polish adults aged between 40 and 70 years; parasitological, microbiological, and mycological data collected before treatment were analyzed. The diversity of oral microbiota, including relatively high prevalences of some opportunistic, potentially pathogenic strains of bacteria, protozoans, and fungi detected in the patients analyzed, may result in increasing risk of disseminated infections from the oral cavity to neighboring structures and other organs. Increasing ageing of human populations is noted in recent decades in many countries, including Poland. The growing number of older adults with different oral health disabilities, who are more prone to development of oral and systemic pathology, is an increasing medical problem. Results of this retrospective study showed the urgent need to pay more attention to the pretreatment examination of components of the oral microbiome, especially to the strains, which are etiological agents of human opportunistic infections and are particularly dangerous for older adults.

In this research, a comparative analysis of results of investigations involving different human populations, in terms of a relation between the oral cavity health and the species composition of mouth microbiota is reported. The purpose of this analysis was to identify and assess microorganisms that could cause health complications in patients with neoplasm requiring dental problem-related surgical management. The patients with the oral cancer surgically treated and those without neoplasm were assessed for their oral health: status of teeth, gingiva, periodontium, and occurrence of inflammatory processes. From each patient, microorganisms isolated of periodontium, dental plaque, and dental pocket swabs were identified in wet and stained microscopic preparations; standard microbiology in vitro techniques were also applied to determine the fungal and bacterial strains. The comparative analysis of results of direct microscopic examinations and in vitro cultures assessment indicated significant differences in prevalences of fungi, parasitic oral protozoans and bacteriae in particular patient’s groups. Yeast-like fungi belonging to Candida genus, mostly of C. albicans group, were identified in 93.75% patients with the oral cancer, while in 25% of individuals assessed without neoplasm. E. gingivalis amoebae were only found in 12.5% patients with the serious disease; no trichomonads were detected in all patients analyzed. Among bacteria species, potentially pathogenic Enterobacteriaceae were found in the patients with oral cancer. The pronounced shift in the microbiota species composition in the patients who needed prolonged treatment due to oral cavity cancer, compared to other generally healthy persons has been showed in this analysis.

Amphizoic amoebae generate a serious human health threat due to their pathogenic potential as facultative parasites, causative agents of vision-threateningAcanthamoebakeratitis (AK). Recently, AK incidences have been reported with increasing frequency worldwide, particularly in contact lens wearers. In our study, severe cases of AK in Poland and respective pathogenic isolates were assessed at clinical, morphological, and molecular levels. Misdiagnoses and the unsuccessful treatment in other ophthalmic units delayed suitable therapy, and resistance to applied chemicals resulted in severe courses and treatment difficulties. Molecular assessment indicated that all sequenced pathogenic corneal isolates deriving from Polish patients with AK examined by us showed 98–100% homology withAcanthamoebagenotype T4, the most prevalent genotype in this human ocular infection worldwide.In vitroassays revealed that the pathogenic strains are able to grow at elevated temperature and have a wide adaptive capability. This study is our subsequentin vitroinvestigation on pathogenicAcanthamoebastrains of AK originating from Polish patients. Further investigations designed to foster a better understanding of the factors leading to an increase of AK observed in the past years in Poland may help to prevent or at least better cope with future cases.

Free-living amoebae of Acanthamoeba genus are ubiquitous in various parts of the world. Some species of these amoebozoans present a serious risk to human health as the causative agents of vision-threatening diseases, Acanthamoeba keratitis. Correct diagnosis requires both a clinical examination of the cornea and amoebic form identification in affected eyes. Despite advances in pharmacotherapy, the infection is difficult to diagnose and to threat. Population dynamics of five different Acanthamoeba strains cultured in vitro under bacteria-free condition in BSC medium, was monitored in terms of diagnostic and therapeutic management. The range of protozoan number in the exponential growth phase, the morpho-physiological status of amoeba forms and their ability to multiply were evaluated. Results of the studies revealed that early and continued monitoring of the strains maintained in an axenic culture showed correlation between the dynamics of cultivated amoebae and the course of the disease, differences in response to pharmacotherapy and the surgical management efficacy. Concluding, the in vitro monitoring of dynamics of Acanthamoeba strains isolated from infected corneas may be important not only for proper diagnosis but also as a useful tool in keratitis management and therapeutic prognosis.

Trophozoites and cysts of free-living Acanthamoeba castellanii present a serious risk to human health as causative agents of human diseases such as fatal granulomatous amoebic encephalitis and Acanthamoeba keratitis that is reported from various part of the world, also in Poland, with increasing frequency, particularly in the contact lens wearers. The amphizoic amoebae are generally extremely resistant to different chemical agents, however, several strains/isolates within A. castellanii may differ in virulence. Among the features considered as associated with the amoeba pathogenicity, temperature tolerance and resistance to different environmental conditions are reported. In the present study, A. castellanii strain cultured in 26 °C after several year passages were tested for sensibility/tolerance to instant temperature changes as well as exposition to deuterium oxide, D2O. Significant decrease of number of viable amoebae during in vitro exposition to D2O occurred, but no changes in trophozoites/cysts ratio. The ability of the strain examined to develop in higher temperature may indicate a wide adaptation reserve and its pathogenic potential.

Pentatrichomonas hominis, a parasitic protozoan often detected in human diarrheic stools, is the cause of severe morbidity in newborns and children, particularly in tropical zones. The flagellate is resistant to many disinfectants and anti-protozoan drugs. Therefore in this study we have synthesized three novel 4,5,6,7-tetrabromobenzimidazole (TBBI) derivatives carrying a polyfluoroalkyl substituent in position 2 of the benzimidazole scaffold, namely 2-trifluoromethyl-TBBI (CF3-TBBI), 2-nonafluorobutyl-TBBI (C4F9-TBBI), and 2-nonadecafluorononyl-TBBI (C9F19-TBBI), that next we tested for their in vitro activity against P. hominis.Widely applied anti-protozoal drug, metronidazole as a reference was used. All the investigated agents were added to 24 h P. hominis cultures; each of them was administered at three different concentrations. Number of the moving trichomonads was determined and compared with the control cultures. Different anti-trichomonal activity occurred depending on a kind of compound and its concentration. C4F9-TBBI was the most effective TBBI derivative tested: the agent, at the highest concentration 24.2 μg/ml, after 72 h reduced the number of viable trichomonads to 44.3%; C9F19-TBBI, at the concentration 24 μg/ml reduced the number of the flagellates to 58.5%. Paradoxically, metronidazole after the same time given at the highest concentration increased trophozoite counts by 464.6% in comparison with the control cultures (100%).