The type of blood used to feed Aedes aegypti females affects their cuticular and internal free fatty acid (FFA) profiles.

Aedes aegypti, the primary vector of various arthropod-borne viral (arboviral) diseases such as dengue and Zika, is a popular laboratory model in vector biology. However, its maintenance in laboratory conditions is difficult, mostly because the females require blood meals to complete oogenesis, which is often provided as sheep blood. The outermost layer of the mosquito cuticle is consists of lipids which protects against numerous entomopathogens, prevents desiccation and plays an essential role in signalling processes. The aim of this work was to determine how the replacement of human blood with sheep blood affects the cuticular and internal FFA profiles of mosquitoes reared in laboratory culture. The individual FFAs present in cuticular and internal extracts from mosquito were identified and quantified by GC-MS method. The normality of their distribution was checked using the Kolmogorov-Smirnov test and the Student's t-test was used to compare them. GC-MS analysis revealed similar numbers of internal and cuticular FFAs in the female mosquitoes fed sheep blood by membrane (MFSB) and naturally fed human blood (NFHB), however MFSB group demonstrated 3.1 times greater FFA concentrations in the cuticular fraction and 1.4 times the internal fraction than the NFHB group. In the MFSB group, FFA concentration was 1.6 times higher in the cuticular than the internal fraction, while for NFHB, FFA concentration was 1.3 times lower in the cuticular than the internal fraction. The concentration of C18:3 acid was 223 times higher in the internal fraction than the cuticle in the MHSB group but was absent in the NFHB group. MFSB mosquito demonstrate different FFA profiles to wild mosquitoes, which might influence their fertility and the results of vital processes studied under laboratory conditions. The membrane method of feeding mosquitoes is popular, but our research indicates significant differences in the FFA profiles of MFSB and NFHB. Such changes in FFA profile might influence female fertility, as well as other vital processes studied in laboratory conditions, such as the response to pesticides. Our work indicates that sheep blood has potential shortcomings as a substitute feed for human blood, as its use in laboratory studies may yield different results to those demonstrated by free-living mosquitoes.

The interaction between cuticle free fatty acids (FFAs) of the cockroaches Blattella germanica and Blatta orientalis and hydrolases produced by the entomopathogenic fungus Conidiobolus coronatus.

The interactions between entomopathogenic fungi and insects serve a classic example of a co-evolutionary arms race between pathogens and their target host. The cuticle, site of the first contact between insects and entomopathogenic fungus, is an important defensive barrier against pathogens. It is covered by a layer of lipids that appears to play a key role in these processes and cuticular free fatty acid (FFA) profiles are consider as a determinant of susceptibility, or resistance, to fungal infections. These profiles are species-specific. The cockroaches Blattella germanica (Blattodea: Blattidae) and Blatta orientalis (Blattodea: Ectobiidae) are unsusceptible to the soil fungus Conidiobolus coronatus (Entomophthorales: Ancylistaceae) infection, therefore we studied the profiles of FFAs in order to understand the defensive capabilities of the cockroaches. The fungus was cultivated for three weeks in minimal medium. Cell-free filtrate was obtained, assayed for elastase, N-acetylglucosaminidase, chitobiosidase and lipase activity, and then used for in vitro hydrolysis of the cuticle from wings and thoraces of adults and oothecae. The amounts of amino acids, N-glucosamine and FFAs released from the hydrolysed cuticle samples were measured after eight hours of incubation. The FFA profiles of the cuticle of adults, and the wings, thoraces and oothecae of both species were established using GC-MS and the results were correlated with the effectiveness of fungal proteases, chitinases and lipases in the hydrolyzation of cuticle samples. Positive correlations would suggest the existence of compounds used by the fungus as nutrients, whereas negative correlations may indicate that these compounds could be engaged in insect defence.

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.

New 1,5 and 2,5-disubstituted tetrazoles-dependent activity towards surface barrier of Candida albicans.

A series of novel tetrazole derivatives was synthetized using N-alkylation or Michael-type addition reactions, and screened for their fungistatic potential against Candida albicans (the lack of endpoint = 100%). Among them, the selected compounds 2d, 4b, and 6a differing in substituents at the tetrazole ring were non-toxic to Galleria mellonella larvae in vivo and exerted slight toxicity against Caco-2 in vitro (CC50 at 256 µg/mL). An antagonistic effect of tetrazole derivatives 2d, 4b, and 6a respectively in combination with Fluconazole was shown using the checker board and colorimetric methods (fractional inhibitory concentration indexes FICIs >1). The most active 2d and 6a displayed an inverse relation between MICs in the presence of exogenous ergosterol, the effect was opposite to Itraconazole and Amphotericin B. The differences between 6a's and 2d's action mode were noted. Combining both flow cytometry and fluorescence image analyses respectively showed the complexity of planktonic and biofilm cell demise mode under the tetrazole derivatives tested. The following evidences for 6a's interaction with fungal membrane were noted: necrosis-like programmed cell death (97.03 ±â€¯0.88), DNA denaturation (no laddering), mitochondrial damage (XTT assay), reduced adhesion to human epithelium (>50% at 0.0313 µg/mL, p ≤ .05), irregular deposit of chitin, and attenuated morphogenesis in mature biofilm. The treatment with 6a reduced pathogenicity of C. albicans during infection in G. mellonella. Contrariwise, 2d enhancing fungal adhesion displayed mechanism targeted to the cell wall (due to the presence of 3-chloropropyl clubbed with aryltetrazole) in the presence of osmotic protector. Under 2d, the accidental cell death (88.60% ±â€¯4.81) was observed. In conclusion, all tetrazole derivatives were obtained in satisfactory yields (60-95%) using efficient, simple and not expensive methods. Fungistatic and slightly anticancer tetrazole derivatives with the novel action mode can circumvent an appearance of antifungal-resistant strains. These results indicate that they are worthy of further studies.

Methods of testing repellent efficiency against ticks

The use of repellents is the most important in the tick-bite protection. The tests of repellents efficiency shall give strict answer whether ticks are repelled effectively or not by a given agent. Methods of testing repellent efficiency can be divided in in three groups: experiments without tick host and host stimuli; studies simulating host stimuli, methods of testing repellents on animals or human volunteers. Studies on protected human volunteers are the nearest practical conditions of repellent use. However, there is sometimes a need of testing products with unknown toxicity to man; in such circumstances their efficiency should be evaluated in experiments in simulated human body conditions but without a person.

Methods of mosquito plague control in Swinoujscie area based on the analysis of species distribution.

OBJECTIVE: Studies conducted in 2013 in Swinoujscie area aimed at determining mosquito species distribution and analyzing sites, productivity and dynamics of larva and adult breeding as well as developing guidelines for effective mosquito control in this area. MATERIALAND METHODS: Entomological studies were conducted from March to September 2013. Distribution of mosquito larvae and adults was investigated. Mosquito larvae were observed mainly in April in transient snow-melt pools. RESULTS: Ochlerotatus cantans, Oc. communis, Oc. annulipes, Oc. punctor were the most predominant mosquito species. Since July, larvae of the following genera: Culex spp., Culiseta spp., Anopheles spp. were collected in standing water bodies. A total of 17 species adult mosquito were identified. Of them, Oc. communis, Aedes vexans, Culex pipiens/torrentium, Oc. Cantans, Oc. caspius predominated over other species. CONCLUSIONS: Mosquito plague in Swinoujscie area can be controlled if constant actions would be undertaken from April (use of microbial biocides for snow-melt mosquito larva control) to August (use of microbial biocides for polygeneration larva species control and use of chemical biocides for adult mosquito control). Furthermore, there is a need for actions that would make environment less friendly to mosquitoes and would help to identify breeding sites of aggressive mosquito species - Aedes vexans. There is also a necessity to educate the inhabitants of Swinoujscie area on the danger resulting from uncontrolled use of insecticides in protected areas and those which are unique from a faunistic perspective.

[Evaluation of effectiveness of several repellents against mosquito bites available at the Polish market]. / Ocena skutecznosci wybranych preparatów dosteipnych na polskim rynku sluzacych do ochrony przed komarami.

UNLABELLED: BACKGROUND. Mosquitoes are blood-sucking insects, nuisance to humans and animals. Their bites cause itching and allergic reactions. These insects are also vectors of several viruses, bacteria and parasites. Protection against mosquitoes is therefore justified and desirable. This can give repellents and products for protection small outdoor areas such as terraces, home gardens. OBJECTIVE. The aim of this study was to evaluate the effectiveness of eight selected products with different formulations used against mosquitoes including: 5 preparations for use on the body or clothing (repellents A, B, C, D, E and 3 products for use in small outdoor spaces (I, J, K). MATERIAL AND METHODS: [corrected] Repellents were tested in laboratory trials, when volunteers were exposed to Aedes aegypti females breeding in the laboratory. Products I, J, K were tested in field trials; volunteers were exposed to female mosquitoes at various ages from the environment (Aedes sp, Culex sp). RESULTS: The results showed that all tested repellents were efficient during 4 hrs. After this time their effectiveness decreased--fast in the case of repellent B (10% DEET), not very fast, but significant--in the case of repellent C (15% DEET). Three products for small area protection gave (each of them) 3-hour protection against mosquito bites. Product K (21,97% allethrin) was 100% effective (no bites at all). CONCLUSIONS: Both kinds of product can give effective protection against mosquito bites. Their use is most effective, cheaper and more safe for the environment method of protection against mosquitoes than chemical spraying of large areas.

[Mosquito control on selected area in Poland after the flood in 2010]. / Zwalczanie komarów na wybranym terenie popowodziowym w Polsce w 2010 roku.

After the flood in 2010 in many regions of Poland mosquitoes occurred in huge number and chemical control of them was performed. In Legionowo district the aerial application of deltamethrin-containing product was done. In the study the efficacy of the treatments was described. Mosquitoes were caught in CDC traps in five places located in the treated area before treatments, after the 1st and after the 2nd treatments chemical. The chemical control resulted in mean reduction of 53.8% in mosquito numbers after the 2nd treatment (48.1%-57.2%). Efficiency results were much lower than those obtained in control programs realized with the use of microbial control agent. Results obtained indicate, that the integrated mosquito control program should be elaborated for this area, enabling the use of biological and chemical control methods to obtain better efficiency and protection of the environment.

[Occurrence of head pediculosis and its control in children's homes in selected provinces of Poland in the years 2007-2009]. / Wystepowanie wszawicy glowowej i jej zwalczanie w domach dziecka w wybranych województwach polski w latach 2007-2009.

Despite civilisation development and the easy access to pediculicides, head pediculosis remains still the social, hygienic and medical problem. In the years 2007 - 2009 in children's homes in selected provinces of Poland the questionnaire survey on the occurrence of head pediculosis and its control have been conducted. From 127 orphanages 61 (48.03%) sent back fulfilled questionnaire. The infestation level ranged from 4.63% (Swietokrzyskie Province, 2009) until 17.63% (Mazowieckie Province 2007) in the surveyed children's homes. The most head pediculosis cases were observed among girls 6 - 12 years old in children's homes from all regions investigated. The profile of pediculicides used had been changed during our study: in the first year the most often pediculicides with the insecticide permethrin were used. In the next years their use decreased, but the use of herbal and silicone pediculicides increased. The efficacy of anti-louse product was the most important factor for the respondents when they choose an pediculicide.

[Synantropic cockroaches (Blattella germanica L.) in hospital environment--microbiological hazard for patients and hospital infections risk assessment]. / Synantropijne karaczany (Blattella germanica l.) w srodowisku szpitalnym - narazenie mikrobiologiczne pacjentów i oszacowanie ryzyka zakazen szpitalnych.

OBJECTIVE: The aim of our study was to determine what a hazard for patients creates the presence of cockroaches in hospital environment. MATERIAL AND METHODS: The probable hospital infections cases in 9 hospitals in Warsaw were found in database of the Country Hospital Morbidity Register for the year 2004 and correlation between such factors as: drug resistance of bacteria isolated from external part of cockroach's bodies, their ability to biofilm building, adherence, resistance to disinfectants, resistance of cockroaches to insecticides, infestation level vs. infections of several body systems was examined. RESULTS: The microbiological hazard of cockroaches in hospital environment has been proven by our findings that some of bacterial strains carried on the body of cockroaches belonged to well known species responsible for hospital infections everywhere The strains resistant to several antibiotics used in hospital and the strains able to form virulence factors were found. Some correlation was found between resistance of cockroaches for biocides and higher infestation of the hospital environment. CONCLUSIONS: Cockroaches infected in hospital environment might be the active carrier of bacterial strains as well as indicator of the bacterial presence on the surfaces in the hospital building not enough treated with disinfectants. On the base of our findings we may suppose that in hospital infections the role of infected cockroaches are less important than the other factors but should be not completely neglected. Surveillance and control of hospital infections should be more completed, connected not only with continuous monitoring of resistance of bacterial strains to antibiotics but also to disinfectants used in hospital as well as evaluation of infestation of the hospital environment and resistance of cockroaches to biocides.

[Bioactive effectiveness of selected disinfective agents on Gram-negative bacilli isolated from hospital environment]. / Biobójcza skutecznosc wybranych preparatów dezynfekcyjnych wobec Gram-ujemnych paleczek wyizolowanych ze srodowiska szpitalnego.

In our study the susceptibility (MIC) of chosen 21 strains of Gram-negative bacilli isolated in hospitals to disinfectant agents (glucoprotamine, sodium dichloroisocyanurate, potassium persulfate), the effectiveness of these disinfectants against selected bacteria and their effectiveness to biofilm forming bacteria was determined. It was found that glucoprotamine showed the highest activity to Gram-negative bacteria. Obtained MIC values for glucoprotamine (except 1 strain of S. marcescens) were 16-64 times lower that MICs for sodium dichloroisocyanurate and 4-32 times lower that MICs for potassium persulfate. The effectiveness of disinfectants containing potassium persulfate or sodium dichloroisocyanurate was 100% tested by carrier method. Glucoprotamine was ineffective against 2 out of 9 strains (18%): E. cloacae and S. marcescens. It was found that disinfectants were more effective against Gram-negative bacteria in carrier methods than for biofilm forming bacteria. 86% of bacteria growing 5 days on a catheter were resistant to working solution of disinfectant containing glucoprotamine (5200 mg/L) or potassium persulfate (4300 mg/L); 66.6% of tested bacteria were resistant to working solution of sodium dichloroisocyanurate (1795.2 mg/L). In our study the highest effectiveness to biofilm forming bacteria showed disinfectant with sodium dichloroisocyanurate, the lowest--with glucoprotamine.