Norovirus infections in the Czech Republic in 2008-2020.

INTRODUCTION: Noroviruses, together with rotaviruses, are the most common cause of viral gastroenteritis in the Czech Republic (CR). The aim of this study was to analyse data on the incidence of norovirus gastroenteritis in the CR and thus to add to the body of knowledge about its significance. MATERIAL AND METHODS: A descriptive analysis was performed of the basic characteristics of norovirus gastroenteritis reported under ICD-10 code A08.1 to the Epidat or ISIN electronic infectious diseases information system between 2008 and 2020. On the basis of reports from five microbiological laboratories, weekly data on confirmed cases of norovirus infection from 2010-2020 were analysed. Databases of microbiology laboratories from across the Czech Republic were searched to determine the number of the laboratories where norovirus infections were diagnosed and the methods used for this purpose in 2008-2020. RESULTS: From 2008 to 2020, 33,575 cases of norovirus gastroenteritis were reported to the infectious diseases information systems, which equates to an annual incidence of 24.5/100,000 population, varying between years from 8.2 to 77.1/100,000. Men accounted for 40.2% of cases with an incidence of 20.1/100,000 compared to 28.8/100,000 recorded in women. Of the total of reported cases, 14,282 patients (42.5%) required hospital admission. Over the whole study period, 7,431 cases of norovirus gastroenteritis were recorded in children under 5 years of age. This age category accounted for 13.7-38.9% of the annual totals of reported cases. The incidences were 101.8/100,000 in children under 5 years of age, 40.1/100,000 in 5-14-year-olds, 12.7/100,000 in 15-64-year-olds, and 38.2/100,000 in the age group 65 years and over. Twenty-four deaths (case fatality rate of 0.07%) were reported as associated with norovirus gastroenteritis at the ages 42-94. In the age categories 15-64 years and 65 years and over, the case fatality rates were 0.02% and 0.24%, respectively. Over the study period, 274 epidemics occurred, during which 16,893 (50.3%) of the total of 33,575 cases were reported. In the epidemic outbreaks, 1,694 (10.0%) patients required hospital admission. The largest outbreak with 5,248 reported cases in 2015 was associated with contamination of the Prague water supply system. Norovirus infections were laboratory diagnosed year-round, peaking in the autumn and winter months. They are currently diagnosed by 81 laboratories in the Czech Republic, 90.1% of which use immunochromatographic tests. CONCLUSION: The study confirmed the highest incidence of norovirus gastroenteritis among children under 5 years of age and the highest case fatality rate in the age group 65 years and over. Over half of the reported cases were outbreak associated. Most laboratories use immunochromatographic tests. The use of more sensitive laboratory methods would improve diagnosis.

Room temperature Fe2+:Cd1-xMnxTe laser generating at 5.4-6 µm.

Six-µm laser generation at room temperature was achieved from Fe2+-doped Cd1-xMnxTe solid-solution active media for the first time, to the best of our knowledge. Laser properties of Fe2+:Cd1-xMnxTe crystals with various concentrations of manganese Mn (x=0.1, 0.52, 0.56, 0.68, and 0.76) were investigated. The increase of Mn content in these crystals was shown to result in an almost similar long-wavelength shift of absorption, fluorescence, and laser output spectra of about ∼60 nm per each 10% of Mn. Laser generation was achieved in all crystals with maximum output energies up to 30 µJ (for x=0.52). The laser central oscillation wavelength is significantly influenced by Mn concentration and varies in the range from 5400 nm up to 6000 nm.

Spectroscopic and laser properties of bulk iron doped zinc magnesium selenide Fe:ZnMgSe generating at 4.5 - 5.1 µm.

The Fe:Zn(1-x)Mg(x)Se (x = 0.19, 0.27, and 0.38) solid solutions spectroscopic properties were investigated and laser oscillations were achieved for the first time. The increase of the magnesium concentration in the Fe:ZnMgSe crystal was shown to result in an almost similar long wavelength shift of both absorption and fluorescence spectra of about 60 nm per each 10% of magnesium. With the Fe:ZnMgSe crystal temperature decrease, the fluorescence spectrum maximum shifts towards shorter wavelength resulting mainly from strong narrowing of the longest wavelength fluorescence line. Laser radiation wavelength dependence on the magnesium concentration as well as on temperature was observed. The Fe:ZnMgSe x = 0.38 laser oscillation wavelength increased from 4780 nm at 80 K to 4920 nm at 240 K using the optical resonator without any intracavity spectrally-selective element. In comparison with the Fe:ZnSe laser operating in similar conditions, these wavelengths at both temperatures were shifted by about 500 nm towards mid-IR region.

2-µm wavelength, high-energy Ho:YLF chirped-pulse amplifier for mid-infrared OPCPA.

A 2-µm wavelength laser delivering up to 39-mJ energy, ∼10 ps duration pulses at 100-Hz repetition rate is reported. The system relies on chirped pulse amplification (CPA): a modelocked Er:Tm:Ho fiber-seeder is followed by a Ho:YLF-based regenerative amplifier and a cryogenically cooled Ho:YLF single pass amplifier. Stretching and compressing are performed with large aperture chirped volume Bragg gratings (CVBG). At a peak power of 3.3 GW, the stability was <1% rms over 1 h, confirming high suitability for OPCPA and extreme nonlinear optics applications.

Smell impairment after tick-borne encephalitis vaccination: case report.

We present a case of hyposmia following administration of a tick-borne encephalitis (TBE) vaccine. The olfactory impairment did not recover during 1-year follow up. In the literature, there is no report of smell deterioration after vaccination against TBE. Physicians should be aware of this rare neurological complication.

First experience with diagnosing astroviral infections in children hospitalized in Pilsen (Czechia).

Between the years 2000-2002 astroviral infection was confirmed in 0.8 % of 2606 children admitted for a diarrheal disease to the University Hospital in Pilsen (Czechia). Astrovirus infections most frequently occurred in the age group between 49-60 months, and 77.3 % of the infections occurred in winter. When the incidence was calculated for these most susceptible age groups, the positive rates were 2.4 % (between 49-60 months) and 1.2 % (between 7-12 months) respectively. On average the hospitalization lasted for 5 d, the diarrhea 3.7 d, vomiting 1.1 d, and 40.9 % of infected children had a raised temperature. In 7 out of 872 stool samples (0.8 %), astrovirus antigen has appeared in the course of the monitored period, i.e. nosocomial astrovirus infection was recorded. In view of the rarity of detecting astroviral infections it is probably not effective to include the diagnosis of these infections in the routine panel when examining the children admitted for gastrointestinal infections. The diagnosis of these infections should, however, be performed within the framework of epidemic incidence and in nosocomial infections.

[Diagnosis of rotavirus infections--comparison of various methods]. / Diagnostika rotavirových infekcí--porovnání ruzných metod.

In 179 samples of faeces from patients hospitalized with diarrhoeal diseases rotavirus infections were examined concurrently by three different sets--the latex agglutination test Diarlex Rota-Adeno (Orion Diagnostica) and two immunoenzyme tests (EIA)--EIA Rotavirus (Test-Line, CR) and IDEIA Rotavirus (Dako Ltd.) By the latex agglutination reaction the rotavirus infection was proved 31 times (17.3%), by the Test-Line test 87 times (48.6%), by the Dako test 96 times (53.6%). During the interval of 0-3 days after the onset of the disease the positivity assessed by different tests was 22.8%, 48.6% and 54.3%, on the 4th-7th day 12.8%, 51.1% and 57.4%, on the 8th and subsequent days 3.7%, 44.4% and 44.4%. Comparison of sets Orion Diagnostica and Dako revealed the sensitivity of the latex agglutination test only as 30.2% and specificity 97.6%. After the 9th day from the onset of the disease the infection was no longer confirmed by the latex agglutination test, while both EIA tests proved the rotavirus antigen up to the 16th day from the onset of the disease.

Er:YAG and alexandrite laser radiation propagation in root canal and its effect on bacteria.

OBJECTIVE: The objective of this study was to compare the bactericidal effect of the Er:YAG (wavelength 2.94 microm) and the Alexandrite (wavelength 0.75 microm) laser radiation. The spreading laser energy in the surrounding hard dental tissues round the root canal was evaluated and the bactericidal effect of both these different laser wavelengths was analyzed. SUMMARY BACKGROUND DATA: The use of a laser to clean and shape the root canal space is the latest method used for cleaning of root canals. The interest in laser endodontics was concentrated on the possibility to extirpate the contents of the root canal, to sterilize and to "melt" the walls of the root canals. The previous reports were performed with CO2, excimer, argon, Nd:YAG, Ho:YAG, and Er:YAG lasers. METHODS: Er:YAG laser system (2.94 microm, energy 100 mJ or 300 mJ, repetition rate 1 Hz, 30 pulses) and alexandrite laser system (0.75 microm, energy 250 mJ, repetition rate 1 Hz, 30 pulses) were prepared and three experimental arrangements were used during the measurements. First the energy transport through the tooth tissue was observed (frontal and side experimental setups) and then, the bactericidal effect was evaluated. RESULTS: It was demonstrated that due to the absorption in the hydroxyapatite and water content in the dentin, the Er:YAG laser radiation is fully absorbed in the root canal wall. This direct influence of the radiation could be expected only close to the sapphire tip. It was found that the tissue, which was not directly affected by the laser radiation, cannot be disinfected by the subablative effect of Er:YAG laser radiation. In the second part of the experiment the real bactericidal effect of Er:YAG ablative energy (300 mJ) could be observed. It was also shown that the alexandrite laser radiation with a wavelength of 0.75 microm spreads through the canal system space and leaks into the surrounding tooth tissues. Both lasers have bactericidal effect. CONCLUSIONS: The pulsed Er:YAG and alexandrite lasers can be efficiently used for killing dental bacteria but the spreading of their radiation in the tooth tissues are different.

High-power Nd:YAG laser picosecond pulse delivery by a polymer-coated silver hollow-glass waveguide.

An oscillator-amplifier high-power Nd:YAG laser system was used for transmission of a single 50-ps-long pulse or a train of pulses through a cyclic olefin polymer-coated silver hollow-glass waveguide. The maximum energy that was transmitted was 150 mJ for the train of pulses and 40 mJ for the single pulse, from which followed a delivered power of 100 GW/cm(2) . The characteristics that were obtained make these waveguides promising for the delivery of high-power laser pulses in medical as well as other applications.

Noncontact Er:YAG laser ablation: clinical evaluation.

OBJECTIVE: The aim of this study is to evaluate the quality of laser ablation in comparison with the classical drilling preparation. METHODS: For the experiment, the Er:YAG laser drilling machine was used. The system had a laser head, water cooler, and power supply with automatic control. Spot size of 300-350 microns was used for the preparation. Repetition rate of 1-4 Hz, and pulse energies of 100-400 mJ with water spray were chosen. Cavity shape in comparison with classical drill, time of preparation, and influence of cavity shape on filling materials retention in accordance with the U.S. Public Health Service System were used. The evaluation criteria for noncontact Er:YAG ablation were done. RESULTS: The cavity shape is irregular, but spot surface has larger area and microretentive appearance. Caries of enamel and dentin were treated with a noncontact preparation. It was possible to remove the old insufficient fillings, except for amalgam or metal alloys. The average number of pulses was 111.22 (SE 67.57). Vibrations of microexplosions during preparation were felt by patients on 14 cavities; however, nobody felt unpleasant pain. The qualities of filling materials in laser cavities were very stable; however, cavo surface margin discoloration of 82-86% of Alfa rating could be a problem. Changes of the color and anatomic form of the tooth were observed in 4-8%. CONCLUSIONS: In comparison with the classical treatment, it could be said that the retention and quality of filling materials is the same or very similar.

Dentin and pulp response to Erbium:YAG laser ablation: a preliminary evaluation of human teeth.

OBJECTIVE: We determined the real effect of Erbium:YAG laser ablation on human teeth in vivo. SUMMARY BACKGROUND DATA: We advocated the idea that overheating of teeth, specially pulp damage can be avoided if correct laser parameters are used. METHODS: We evaluated human premolars scheduled for extraction during orthodontic treatment. Before tooth extraction, an oval cavity preparation was made with a pulsed Er:YAG laser. After extraction, the teeth were decalcified for 6 weeks. Routine staining with haematoxylin and eosin was performed on longitudinal section. One hundred seventy-two sections were prepared and examined in a light microscope. RESULTS: Under Er:YAG laser application, reduction of the dentin layer was observed. Dentinal tubules had a radial course up to the surface. No cracks or structural injury were observed. Inflammatory reaction in the pulp was not found. The vascularity of the pulp was normal. The odontoblasts were of the usual spindle-like or star-like cell shape. The cementum and epithelial attachment were healthy. No changes of structure or indications of inflammation were observed. CONCLUSIONS: The results of this in vivo experiment on human teeth confirm safety of Er:YAG laser ablation of enamel and dentin under the conditions described.

Evaluation of the surface changes in enamel and dentin due to possibility of thermal overheating induced by Erbium:YAG laser radiation.

This study investigates the thermal danger of Erbium (Er):YAG laser ablation. Classical preparation techniques have many disadvantages caused by unfavorable changes of temperature, pressure, and by mechanical vibrations. The effect of mechanical vibrations and pressure is eliminated by use of laser ablation technique. The purpose of this study was to analyze the side effects resulting from thermal changes of enamel and dentin in extracted human teeth subjected to pulsed Er:YAG laser radiation using both wet and dry ablation methods. The micrographs of the sections were checked and measured afterwards. The effect of the investigated laser irradiation on the origin of cracks was analyzed in the scanning electron microscope. The hard structures of the teeth were observed under transmitted and polarized light. The occurrence of cracks can be directly correlated to overheating during dry enamel ablation, because heat is generated by absorption of the laser beam by enamel and dentin. The addition of water mist during irradiation not only enables rapid ablation of enamel and dentin, but offers thermal protection to the pulp. The heat changes to the pulp caused by an energy level of 200 mJ from the tested laser system may be reduced by adding a fine water spray during the lasing procedure.