Repellents as a major element in the context of prevention of tick-borne diseases

In Poland, out of the 21 species of ticks described, two species have the greatest epidemiological significance: Ixodes ricinus and Dermacentor reticulatus. Their participation in the transmission of etiologic agents of vector diseases such as Lyme disease, tick-borne encephalitis, human granulocytic anaplasmosis, babesiosis, rickettsiosis and many others is widely known. Due to the often severe and sometimes fatal course of diseases transmitted by ticks, a great deal of emphasis is placed on prophylactic activities, minimizing the possibility of biting and transfering pathogens along with the arachnid saliva. In addition to means of personal protection, including appropriate clothing, protective vaccinations, avoiding tick habitats or body checking after returning from this type of places, one of the most important elements of anti-tick prevention is the use of effective repellents. The key role of using the repellent is to discourage the arthropod from attacking and to prevent it from taking food, as a result of which there is no phenomenon of transmission of pathogens from the hematophage to the host organism. The most commonly used substances with arthropod repellent properties are: N-N-diethylm-toluamide (DEET), 3-(N-acetyl-N-butyl) aminopropionic acid ethyl ester (IR3535), icaridine, permethrin and essential oils. However, it should be remembered that no repellent ever protects 100% all the time after application - its use should be considered as one of many elements of personal protection in the prevention of tick bites.

Susceptibility of Dermacentor reticulatus tick to repellents containing different active ingrediens

INTRODUCTION: Ticks are vectors of human and animal diseases. MATERIALS AND METHODS: The aim of this study was to investigate the efficacy of four different formulations containing DEET, Icaridin, IR3535 and mix of three compounds: DEET, IR3535 and geraniol, against Dermacentor reticulatus ticks. RESULTS: The repellent effectiveness of these products to adult ticks was different. At 90 minutes after application the repellent A (DEET 30%), repellent D (DEET 30%, IR3535 20%, geraniol 0.1%) and repellent G (IR3535 12%) exhibited a 100% effectiveness in protection against ticks, but the efficacy of repellent C (Icaridin 20%) dropped to 95%. DISCUSSION: DEET is considered by many authors to be the 'gold' standard of insect repellents, and we have also confirmed this in our studies with Dermacentor reticulatus. DEET expressed the higher repellency after 7 hours of application (90%) comparing to other formulation - repellent D containing DEET 30%, IR3535 20% and geraniol 0.1%, whose effectiveness dropped to 60%. Repellents C (Icaridin 20%) and G (IR3535 12%) were effective only up to four hours after application (the efficacy was 85% and 40%, respectively). CONCLUSIONS: DEET has proven to be the most effective repellent against Dermacentor reticulatus ticks.

Galleria mellonella L. as model organism used in biomedical and other studies

Comparative of studies of genomes of invertebrates and humans shows that in invertebrates including insects there are numerous homologues of human's genes coding proteins involved in recognition pathogens or transduction of the expression signal. Thanks this features, insects such as Drosophila melanogaster M., Blattella germanica L., Culex quinquefasciatus S., Bombyx mori L. and Galleria mellonella L. are used in studies on virulence, host resistance or in assessing the in vivo efficacy of antibiotics, fungicides and other biologically active substances. G. mellonella (greater wax moth) are rapid growth, high fertility, size and short life cycle insects- these are features that should be met by good model organisms; therefore the number of researches with larvae of wax moth as the model organism for pathogens assays grows from year to year. This is showing by number of scientific publications about infection's model of G. mellonella. An obstacle in the wide use of G. mellonella caterpillars as a model in biomedical research is the lack of standardized breeding of these insects, which would guarantee the reproducibility of the obtained results and lack of procedures and standards according to which biomedical research will be carried out. Despite this, the G. mellonella model can be used in the initial analysis before conventional in vivo tests and to reduce the number of tests performed on mammals.

Bayesian probability estimates are not necessary to make choices satisfying Bayes' rule in elementary situations.

This paper has two aims. First, we investigate how often people make choices conforming to Bayes' rule when natural sampling is applied. Second, we show that using Bayes' rule is not necessary to make choices satisfying Bayes' rule. Simpler methods, even fallacious heuristics, might prescribe correct choices reasonably often under specific circumstances. We considered elementary situations with binary sets of hypotheses and data. We adopted an ecological approach and prepared two-stage computer tasks resembling natural sampling. Probabilistic relations were inferred from a set of pictures, followed by a choice which was made to maximize the chance of a preferred outcome. Use of Bayes' rule was deduced indirectly from choices. Study 1 used a stratified sample of N = 60 participants equally distributed with regard to gender and type of education (humanities vs. pure sciences). Choices satisfying Bayes' rule were dominant. To investigate ways of making choices more directly, we replicated Study 1, adding a task with a verbal report. In Study 2 (N = 76) choices conforming to Bayes' rule dominated again. However, the verbal reports revealed use of a new, non-inverse rule, which always renders correct choices, but is easier than Bayes' rule to apply. It does not require inversion of conditions [transforming P(H) and P(D|H) into P(H|D)] when computing chances. Study 3 examined the efficiency of three fallacious heuristics (pre-Bayesian, representativeness, and evidence-only) in producing choices concordant with Bayes' rule. Computer-simulated scenarios revealed that the heuristics produced correct choices reasonably often under specific base rates and likelihood ratios. Summing up we conclude that natural sampling results in most choices conforming to Bayes' rule. However, people tend to replace Bayes' rule with simpler methods, and even use of fallacious heuristics may be satisfactorily efficient.