[Pediatric head lice: taxonomy, incidence, resistance, delousing]. / Ves detská: systematika, výskyt, rezistence, odvsivování.

Based on the current knowledge, head louse (Pediculus capitis) and body louse (Pediculus humanus) are two different species that infest specific parts of the human body and do not interbreed in vivo. In 1991-2002, 6 257 cases of pediculosis were reported in the Czech Republic while 3 138 000 pediculicide packagings, i.e. about 500 times as many as the number of cases, were marketed. Between October 2004 and February 2005, a total of 531 children aged between 6 and 15 years from 16 selected schools in the Zlín and Olomouc regions were screened by dry hair combing. Living lice were detected in 14.1% of the enrolled children and dead nits alone were observed in other 9.8% of the subjects. In vitro tests revealed that the collected head lice were highly resistant to malathion, the active ingredient of Diffusil H 92 M. The number of reported cases of pediculosis roughly doubled in 2005.

Pulpal anaesthesia for mandibular central incisor teeth: a comparison of infiltration and intraligamentary injections.

AIM: This study compared the anaesthetic efficacy of infiltration and intraligamentary injections in the permanent mandibular central incisor. METHODOLOGY: Twelve healthy volunteers received each of the following methods of anaesthesia for one of their mandibular central incisors over four visits. 1 Labial infiltration of 1.0 mL. 2 Lingual infiltration of 1.0 mL. 3 Labial infiltration of 0.5 mL plus lingual infiltration of 0.5 mL. 4 Intraligamentary injection of (118 mL. Two percent lidocaine with 1: 80 000 adrenaline and 30 gauge needles were used throughout. Electrical pulp testing was performed before injection and every 2 min up to 30 min after the injection. Injection discomfort was recorded on a 100-mm visual analogue scale. Data were compared with ANOVA, Student's t-test and chi2 tests. RESULTS: Anaesthesia varied between techniques(F = 9.3, P < 0.001). The incidence of anaesthesia at any time was as follows: 50% success for labial infiltration; 50% success for lingual infiltration: 92% success for combined labial and lingual infiltration; 0% success for intraligamentary injections (chi2 = 20; P < 0.001). The mean (+/-SD) VAS score for intraligamentary injection discomfort was 28 +/- 12 mm, for buccal infiltrations 17 +/- 8 mm and for lingual infiltrations 16 +16 mm. Intraligamentary injections were more uncomfortable than buccal (t = 3.7: P < 0.01) and lingual infiltrations (t = 2.67: P < 0.05). CONCLUSIONS: The most reliable method of the techniques investigated for obtaining pulpal anaesthesia in mandibular permanent central incisors was a combination of labial and lingual infiltration. Intraligamentary injections were unreliable and were more uncomfortable than infiltrations in the mandibular central incisor region.

The effect of moisture and blood contamination on bond strength of a new orthodontic bonding material.

The practice of orthodontics often requires the bonding of brackets under difficult conditions of moisture and/or blood contamination. Transbond MIP (3M Unitek, Monrovia, Calif) is a hydrophilic primer designed to bond in moist conditions. This study evaluated the bond strength of Transbond MIP under dry, moist, and blood-contaminated conditions. Ninety human premolars were bonded in 3 equal groups with Transbond MIP after acid etching; the enamel surfaces were either dry, moist, or contaminated with human blood. The shear bond strength was recorded. Dry bonding resulted in a significantly higher bond strength (15.69 MPa) than moist (12.89 MPa) or blood-contaminated (11.16 MPa) bonds. However, all bond strengths were in excess of previous reports of required clinical bond strength, and it was concluded that Transbond MIP is a suitable adhesive for bonding in conditions of poor moisture control or blood contamination.

A resistance of head lice (Pediculus capitis) to permethrin in Czech Republic.

An outbreak of pediculosis at primary schools was recorded in the Czech Republic in 1992. Almost 20% of children in some schools were infested. This outbreak can be attributed to the resistance of head lice to permethrin, which has not been mentioned in literature yet. The resistance factors established in three towns range between 2 and 385 and between 5 and 557 for LC50 and LC90 values, respectively. This resistance has developed after exclusive use of pyrethroids lotion and shampoo in the Czech Republic since 1978, and it was accompanied by a cross-resistance to d-phenothrin and bioalethrin. But the susceptibility of head lice to malathion and pirimiphos-methyl in 1992 was very similar to that found in 1981. The lotion containing 0.3% of malathion (Diffusil H92 M) has been fully effective against the resistant lice. When introduced into the practice, it quickly reduced the infestation of children in primary schools. The other lotion and shampoo containing 0.3% and 0.7% of pirimiphos-methyl respectively were found to be effective as well.

Susceptibility to DDT and some other insecticides of head lice (Pediculus capitis De Geer) in Czechoslovakia.

For testing the susceptibility of the head louse to insecticides impregnated bunches of polyamide fibres, whose diameter resembled that of human hair (0.1 mm) were used. In this manner a low mortality of control lice collected from infected persons was obtained (2.9% after 16 hours of exposure). Even after 25 years of DDT use no apparent resistance could be demonstrated in 25 tested louse populations and cross resistance to permethrin in 7 tested populations. The diagnostic concentration for resistance to pp'-DDT was established at 1%. Of the tested insecticides the highest toxicity was shown by malathion (LC50 = 0.000 018%), pirimiphos-methyl had on average a twice lower toxicity, trichlorphon 104 times lower, tetramethrin 1220 times lower, permethrin 2.5 times lower and pp'-DDT 630 times lower toxicity.

Effectiveness of fenitrothion for area control of ticks Ixodes ricinus (L.).

Susceptibility to fenitrothion in all stages of unfed ticks Ixodes ricinus increases with their age and this fact is reflected in the effectiveness of various dosages of insecticides applied for area control. The following minimum, but fully effective dosages of the dust Metation P-5 and the spray Metation E-50 (both preparations contain fenitrothion) for application in separate seasons have been ascertained: In September and October 1 kg of fenitrothion per ha of treated area ensures complete control of unfed ticks until the winter of current year. In Aril 3 kg of fenitrothion per ha is necessary, if tick control is to be ensured until the appearance of the new generation, i.e. until the end of August. In May the control of unfed ticks is ensured by 1 kg of fenitrothion per ha, in June to August by 0.3 kg per ha is fully efficacious.