Uninvited guests: traditional insect repellents in Estonia used against the clothes moth Tineola bisselliella, human flea Pulex irritons and bedbug Cimex lectularius

Extensive folklore records from pre-modern Estonia give us an excellent opportunity to study a variety of local plant knowledge and plant use among the peasantry in various parts of the country. One important biocultural domain where plant knowledge has been crucial was in the various methods of combating different ectoparasites that cohabited and coexisted with humans and their domestic animals. Some of these methods were widely known (world-wide, Eurasia, Europe, Baltic Rim), while others were more local. Here we discuss ways of reducing clothes moths Tineola bisselliella (Hummel) (Lepidoptera: Tineidae), human fleas Pulex irritons L. (Siphonaptera: Pulicidae) and bedbugs Cimex lectularius L. (Hemiptera: Cimicidae) with the help of plants. Various taxa used as traditional repellents have been identified. The use of plants as repellents and their toxic principles are also discussed from a comparative perspective.

[A possibility of using some pyrethroids to prevent plague in the Siberian natural foci of the souslik type]

Experiments have established that the pyrethroids deltamethrin and cypermethrin (decis and cimbush) may be used in the Siberian natural plague foci for not only emergency, but also early prevention of plague. This substantially expands and simplifies the possibility of organizing disinfection actions and reduces the cost of treatments. The findings are determined by the specific features of the biology and ecology of fleas inhabiting in the natural plague foci of the souslik type in a continental climate area. The specific features include the coincidence of preimago stages and the larger proportion of an adults to rodent nests; the low migration of imagoes from the inhabiting nests to the ground surface, only one insect generation that can develop within a comparatively short (4-5-month) warm period of a year.

Prevalence of flea infestation in dogs and cats in Hungary combined with a survey of owner awareness

A survey was conducted in order to gain current information on flea species (Siphonaptera: Pulicidae) infesting dogs and cats living in urban and rural areas of Hungary, along with data on the factors that affect the presence, distribution and seasonality of infestation. In addition, owner awareness of flea infestation was evaluated. Practitioners in 13 veterinary clinics were asked to examine all dogs and cats attending the clinic and to collect fleas, when present, on 2 days in each month from December 2005 to November 2006. They also completed a questionnaire for each animal examined. A total of 319 dogs (14.1%) were found to be infested; the highest prevalence (27.1%) of infestation on dogs occurred in August and the lowest (5.4%) in May. Prevalence of fleas on cats was higher (22.9%); the highest (35.0%) and lowest (8.1%) prevalences occurred in July and April, respectively. Fleas were more prevalent in rural (387/1924 animals, 20.2%) than in urban (161/1343 animals, 12.0%) areas. Three species, Ctenocephalides felis (Bouché), Ctenocephalides canis (Curtis) and Pulex irritans L., were found. On dogs, the prevalence of C. canis alone was 53.0%, whereas that of C. felis alone was 36.0%. Only 19 specimens of P. irritans were found on 14 dogs from rural habitats only. Prevalence of C. felis only on cats was 94.3%; the remaining cats were infested with either C. canis or with mixed infestations of C. felis and C. canis. More than half (51.4%) of the owners of infested dogs and cats had not used flea control products in the past year or more, and five times as many owners in rural than urban areas had not used flea control products in the same period. Very few owners reported having attempted to kill fleas in their animals' environment; instead, they believed that fleas were acquired from other cats or dogs.

Comparative in vivo adulticidal activity of a topical dinotefuran versus an imidacloprid-based formulation against cat fleas (Ctenocephalides felis) on cats

Fleas cause significant discomfort to pet cats and distress to their owners and are also vectors of disease severe infestations can cause anemia or flea allergy dermatitis and can lead to infections with Dipylidium caninum and Bartonella henselae. Rapid flea kill is an important feature of flea preventives. The efficacy of dinotefuran (Vectra for Cats and Kittens, Summit VetPharm) was compared with that of imidacloprid (Advantage, Bayer Animal Health) against Ctenocephalides felis when applied topically once on day 0. Cats were infested with 100 (+-3) C. felis on study days -1, 8, 15, 22, and 29. Live fleas were counted on study days 0 (2, 6, and 12 hours after treatment), 9, 16, 23, 29 (2, 6, and 12 hours after infestation), and 30. Cats treated with dinotefuran had significantly (P less than .05) fewer fleas than the control cats at all posttreatment examinations except day 29 at 2 hours after infestation and significantly (P less than .05) fewel fleas than cats treated with imidacloprid on days 0 (2 hours after treatment), 9, 16, 23, 29 (6 and 12 hours after infestation), and 30.

Efficacy of a combination of a fipronil-(S)-methoprene spot-on formulation and a deltamethrin-impregnated collar in controlling fleas and sandflies on dogs

This study investigated the use of two commercial products, a deltamethrin-impregnated collar and a fipronil-(S)-methoprene spot-on formulation, in combination to protect dogs against sandflies and fleas when they live in or travel to leishmaniasis-enzootic areas. Interactions, tolerance, and efficacy were evaluated. The combination was well tolerated by the six treated dogs. The antifeeding effect on Phlebotomus perniciosus ranged from 89.6% (day 1) to 99.51% (day 21) and exceeded 95% from day 7 through the end of the study; the mortality effect against P. perniciosus ranged from 87.52% (day 22) to 96.82% (day 15). The combination was 100% effective in controlling Ctenocephalides felis felis infestations for 36 days after treatment. These results suggest that it is feasible and advantageous to combine these two commercial products to protect dogs against sandflies and fleas in leishmaniasis-enzootic areas.

Use of a chitin synthesis inhibitor to control fleas on wild rodents important in the maintenance of plague, Yersinia pestis, in California

A study was designed to test the insect development inhibitors fluazuron and lufenuron for the control of fleas on sylvatic rodents as an adjunct to the control of plague. Historical data of flea burden from 15 prior years of study at Chuchupate Campground, Ventura County, CA, were compared to six years of treatment period data to determine if fluazuron and lufenuron were effective in controlling flea densities. The insect development inhibitors, delivered systemically via a feed cube, reduced flea loads effectively on California ground squirrels (Spermophilus beecheyi), long-eared woodrats (Neotoma macrotis), and mice (Peromyscus spp.) but not on Merriam's chipmunks (Tamias merriami).

[Activity of neem extract on the embryonary development of Ctenocephalides felis felis (Bouché, 1835) (Siphonaptera: Pulicidae)]

The present study had as objective to evaluate the activity of limonoid azadiractin, extracted of the seeds of the plant Azadirachta indica, neem, on the embryonary development of Ctenocephalides felis felis. A dog was sprayed with the formulation 10%, another dog was kept as control, without treatment. Both had been infested weekly with 600 fleas, in the ratio of 1:1 between males and females. The deriving positions of the infestations had been incubate per seven days in assay pipes, and evaluated it percentage of emerging of flea eggs, comparing themselves the averages of the groups treat and have controlled. The extract of nim presented activity on the embryonary development of C. f. felis, keeping superior levels of effectiveness 80% until day +14, beyond diminishing the position and inhibiting the development between urging larval of the percentage of larvae that had come out.

Impact of planting dates and insecticide strategies for managing crucifer flea beetles (Coleoptera: Chrysomelidae) in spring-planted canola

Integration of cultural practices, such as planting date with insecticide-based strategies, was investigated to determine best management strategy for flea beetles (Phyllotreta spp.) (Coleoptera: Chrysomelidae) in canola (Brassica napus L.). We studied the effect of two spring planting dates of B. napus and different insecticide-based management strategies on the feeding injury caused by fleabeetles in North Dakota during 2002-2003. Adult beetle peak emergence usually coincided with the emergence of the early planted canola, and this resulted in greater feeding injury in the early planted canola than later planted canola. Use of late-planted canola may have limited potential for cultural control of flea beetle, because late-planted canola is at risk for yield loss due to heat stress during flowering. Flea beetle injury ratings declined when 1) the high rate of insecticide seed treatment plus a foliar insecticide applied 21 d after planting was used, 2) the high rate of insecticide seed treatment only was used, or 3) two foliar insecticide sprays were applied. These insecticide strategies provided better protection than the low rates of insecticide seed treatments or a single foliar spray, especially in areas with moderate-to-high flea beetle populations. The foliar spray on top of the seed treatment controlled later-emerging flea beetles as the seed treatment residual was diminishing and the crop became vulnerable to feeding injury. The best insecticide strategy for management of flea beetle was the high rate of insecticide seed treatment plus a foliar insecticide applied at 21 d after planting, regardless of planting date.

Comparative efficacy of imidacloprid, selamectin, fipronil-(S)-methoprene, and metaflumizone against cats experimentally infested with Ctenocephalides felis

Four active ingredients--imidacloprid selamectin, fipronil-(S)-methoprene, and metaflumizone--were tested to assess the speed of flea kill against existing flea infestations and subsequent reinfestations. Thirty flea-infested cats were allocated to four treatment groups and one untreated control group. Flea counts were performed 6, 18, and 48 hours after treatment (day 0) and 2, 4, and 24 hours after weekly flea reinfestations. Cats were also reinfested with fleas after the 6- and 18-hour counts on day 0 and after the 2- and 4-hour counts on subsequent count days. Imidacloprid provided significantly greater flea kill at diverse time points. At the 24-hour counts, all compounds showed expected and similar high efficacies. On study day 34, imidacloprid showed the highest efficacy at 24 hours after reinfestation, with 90.8% flea reduction compared with 55.7% to 67.4% in the other treatment groups. A single topical application of imidacloprid provided a high efficacy in the early elimination of adult fleas, limiting the risk of pathogen transmission and flea allergy dermatitis.

Biocidal activity of three wood essential oils against Ixodes scapularis (Acari: Ixodidae), Xenopsylla cheopis (Siphonaptera: Pulicidae), and Aedes aegypti (Diptera: Culicidae)

The biocidal activity of three steam distilled wood essential oils-incense cedar, Calocedrus decurrens (Torr.) Florin; Port-Orford-cedar, Chamaecyparis lawsoniana (A. Murr.) Parl.; and western juniper, Juniperus occidentalis (Hook)--were evaluated against adult Aedes aegypti (L.) (Diptera: Culicidae) and Xenopsylla cheopis (Rothchild) (Siphonaptera: Pulicidae) and nymphal Ixodes scapularis Say (Acari: Ixodidae). In vitro laboratory bioassays were conducted to establish baseline dose-mortality data through 24 h. Incense cedar heartwood was the most toxic to all three vector species followed in order of activity by western juniper and Port-Orford-cedar based on LC50 and LC90 values. Ae. aegypti were substantially more susceptible to the oils than either I. scapularis or X. cheopis.

Efficacy of fipronil-(S)-methoprene on fleas, flea egg collection, and flea egg development following transplantation of gravid fleas onto treated cats

The goal of this study was to assess the insect growth regulator activity of the combination product fipronil-(S)-methoprene under a severe challenge model. Gravid fleas were allowed to feed on untreated donor cats for 48 hours before being transplanted onto untreated control cats and treated cats (treated once on day 0); 24 hours later, adult fleas were collected from all cats and counted to assess the 24-hour kill efficacy against the transplanted fleas, and flea eggs were collected and incubated to assess viability. The process was repeated weekly for 11 weeks. The 24-hour efficacy against transplanted adult fleas in the treated group was about 100% for the first 3 weeks and gradually declined to 93.4% by week 6. Egg production numbers were reduced on the treated cats compared with controls, with geometric mean egg counts on treated cats reduced from 76.9% to 96.3% during the initial 6 weeks of the study. The combination product was 100% ovicidal through day 56 and was still about 98% effective against eggs at the end of the study (day 76).

Efficacy of selamectin and fipronil-(S)-methoprene spot-on formulations applied to cats against adult cat fleas (Ctenocephalides felis), flea eggs, and adult flea emergence

A study was conducted to evaluate the efficacy of selamectin and fipronil-(S)-methoprene against adult cat fleas (Ctenocephalides felis), flea egg production, and the viability of flea eggs collected from treated cats. Cats were infested with approximately 50 adult fleas 2 days before treatment and weekly thereafter; flea eggs were collected and counted on days 0, 1, 2, and 3 and 48 and 72 hours after each weekly flea infestation. Live fleas were collected approximately 72 hours after treatment or infestation. Compared with fipronil-(S)-methoprene, selamectin provided significantly greater control of adult fleas from days 24 to 31 and significantly greater reduction in egg production from days 16 to 45. For the most part, both products significantly impacted larval and adult emergence for the entire 6-week study, with fipronil-(S)-methoprene providing significantly greater reduction in larval and adult emergence at week 6.

Comparison of the activity of selamectin, imidacloprid and fipronil for the treatment of cats infested experimentally with Ctenocephalides felis felis and Ctenocephalides felis strongylus

Twenty adult, domestic short hair cats were randomly allocated into four groups of five cats and housed in separated cages. Each cat was infested with 25 fleas Ctenocephalides felis felis and 25 Ctenocephalides felis strongylus and 2 days later (day 0) the cats in group 1, 2 and 3 received a spot on application of selamectin, imidacloprid or fipronil, respectively, while the cats in group four were not treated. The cats were combed 48 h later, the fleas were removed, counted and their subspecies were determined. All the cats were reinfested with the same number of the two subspecies of fleas on days 7, 14, 21, 29 and 35. The efficacy of each treatment was calculated 48 h after each infestation. The mean number of fleas on the control cats was 16.4 C. f. felis and 13.4 C. f. strongylus. The three treatments were effective for the first 31 days for C. f. felis and for the full 37 days for C. f. strongylus. Over the first 31 days, the efficacy of selamectin ranged from 89 to 100% and 85 to 100% against C. f. felis and C. f. strongylus, respectively, the efficacy of imidacloprid ranged from 76 to 100% and 92 to 100% and the efficacy of fipronil ranged from 98 to 100% and 97 to 100% against C. f. felis and C. f. strongylus. There were no significant differences between the control of C. f. felis and C. f. strongylus by the three products.

[Questionnaire on the incidence and control of fleas in dogs and cats presented to German small animal practices]

2590 small animal practitioners in Germany have been asked by a questionnaire from which 1694 (65.4%) replied. 1186 of these veterinarians (70%) often see ectoparasite infestation. Fleas are predominant and occur on cats (1016/60%), followed by dogs (424/25%), small mammals and birds (254/15%). Flea infestations on dogs and cats are observed throughout the year, but the prevalences are generally higher during the summer season. The results reveal that topically administered spot-on formulations is the most popular method used for flea control. The most common applied antiparasitic substances both in dogs and in cats were fipronil (535/31.6%; 690/40.7%), imidacloprid (290/17.1%; 417/24.6%) and selamectin (267/15.8%; 319/18.8%). Due to 771 (45.5%) of the answering veterinarians the animal owner himself, and according 694 (41%) respectively 229 (13.5%) of the replies the veterinarian or the veterinary technician applies the antiparasiticide onto the skin. 1457 veterinarians (86%) administer compounds against adult fleas and their developmental stages also in the animal's environment.

Indole Diterpenoid Synthetic Studies. The Total Synthesis of (+)-Nodulisporic Acid F

[structure: see text] A stereocontrolled total synthesis of (+)-nodulisporic acid F, the simplest member of a family of novel ectoparasiticidal agents, has been achieved. Highlights of the effective modular synthetic strategy include anionic union of a tricyclic lactone with o-toluidine via our 2-substituted indole synthetic protocol, an optimized C-ring construction protocol, and a late-stage installation of the alpha,beta-unsaturated carboxylic acid side chain via the B-alkyl Suzuki-Miyaura cross-coupling tactic.

Ectoparasites and age-dependent survival in a desert rodent

Host age is one of the key factors in host-parasite relationships as it possibly affects infestation levels, parasite-induced mortality of a host, and parasite distribution among host individuals. We tested two alternative hypotheses about infestation pattern and survival under parasitism in relation to host age. The first hypothesis assumes that parasites are recruited faster than they die and, thus, suggests that adult hosts will show higher infestation levels than juveniles because the former have more time to accumulate parasites. The second hypothesis assumes that parasites die faster than they are recruited and, thus, suggests that adults will show lower infestation levels because of acquired immune response and/or the mortality of heavily infested juveniles and, thus, selection for less infested adults. As the negative effects of parasites on host are often intensity-dependent, we expected that the age-related differences in infestation may be translated to lower or higher survival under parasitism of adults, in the cases of the first and the second hypotheses, respectively. We manipulated ectoparasite numbers using insecticide and assessed the infestation pattern in adult and juvenile gerbils (Gerbillus andersoni) in the Negev Desert. We found only a partial support for age-dependent parasitism. No age-related differences in infestation and distribution among host individuals were found after adjusting the ectoparasite numbers to the host's surface area. However, age-related differences in survival under parasitism were revealed. The survival probability of parasitized juveniles decreased in about 48% compared to unparasitized hosts while the survival probability of adults was not affected by ectoparasites. Our results suggest that the effect of host age on host-parasite dynamics may not explicitly be determined by age-dependent differences in ectoparasite recruitment or mortality processes but may also be affected by other host-related and parasite-related traits.

New methods and strategies for monitoring susceptibility of fleas to current flea control products

A flea larval bioassay was developed by an international team of scientists to monitor the susceptibility of fleas (Ctenocephalides felis) to imidacloprid (Advantage, Bayer HealthCare). The assay was validated using laboratory and field isolates of C. felis. Flea eggs representing different field isolates of C. felis were collected by veterinarians in the United States, United Kingdom, and Germany. Of the 972 flea isolates obtained during the 5-year study, 768 contained sufficient numbers of eggs to conduct the larval bioassay. Greater than 5% survival occurred for only six of the field isolates evaluated. Further evaluation and analysis of these isolates demonstrated that they did not differ significantly in their susceptibility to imidacloprid from the reference strains used to develop the assay. Collections of field flea isolates will continue in an attempt to detect and document any change in the susceptibility of field flea populations to imidacloprid.

Evaluation of the efficacy of dill apiol and pyriproxyfen in the treatment and control of Xenopsylla cheopis flea Roths (Siphonaptera: Pulicidae)

The effect of LC50 of the isolated dill apiol compound and pyriproxyfen caused significant prolongation in the first gonotrophic cycle and great reduction in the percentage of female (Xenopsylla cheopis) reproductive potential as well as egg hatchability. The results indicated that, the larval treatments inhibited the ovarian development and evolved drastic changes in the ovarian histology and histochemistry. The two tested compounds reduced the vitellogenesis and synthesis of carbohydrates, protein, DNA & RNA materials and lipids in oocytes. The two compounds are similar in their mode and site of action.

Field trial of the efficacy of a combination of imidacloprid and permethrin against Tunga penetrans (sand flea, jigger flea) in dogs in Brazil

In a field trial in Brazil 17 dogs penetrated by females of the jigger flea, Tunga penetrans, were topically treated with a combination of 10% imidacloprid and 50% permethrin (Advantix), while 17 dogs remained untreated. The follow-up controls on days 7, 14, 21 and 28 post-treatment clearly showed that, beginning from day 7, the flea load in treated dogs decreased, so that most of the dogs became free of tungiasis lesions, while in the untreated group the flea load remained high. Since the dogs distribute the flea eggs throughout the village, leading to a high incidence of tungiasis in humans, treatment of dogs probably also decreases the number of cases of tungiasis in the latter.

Extract of the seeds of the plant Vitex agnus castus proven to be highly efficacious as a repellent against ticks, fleas, mosquitoes and biting flies

About 70 plant extracts were tested for their ability to repel the attacks of blood-sucking arthropods. It was found that a CO2 extract of the seeds of the Mediterranean plant Vitex agnus castus (monk's pepper) can be used as a spray to keep away especially Ixodes ricinus and Rhipicephalus sanguineus ticks from animals and humans for at least 6 h. In addition mosquitoes, biting flies and fleas are also repelled for about 6 h.

Comparative speed of kill of selamectin, imidacloprid, and fipronil-(S)-methoprene spot-on formulations against fleas on cats

The speed of kill of selamectin, imidacloprid, and fipronil-(S)-methoprene against Ctenocephalides felis infestations on cats for one month following a single treatment was evaluated. Eighty cats were randomly allocated so that there were 20 cats in four different treatment groups. On Days -2, 7, 14, 21, and 28, each cat was infested with 100 adult C. felis from the Kansas 1 flea strain. Following initial application only imidacloprid had caused a significant reduction in adult fleas on treated cats within 6 hours, but by 24 hours all three formulations had killed 96.7% of the fleas. At 7 days post treatment, all three formulations reduced flea populations within 6 and 24 hours by 68.4% and 99.4%, respectively. At 21 and 28 days after treatment, none of the formulations killed significant numbers of fleas as compared to controls within 6 hours of infestation. At 28 days after treatment, selamectin, fipronil-(S)-methoprene, and imidacloprid had killed 99.0%, 86.4%, and 72.6% of the fleas within 48 hours of infestation, respectively. This study demonstrates that the speed of kill of residual flea products on cats decreases throughout the month following application. It also demonstrated that selamectin provided the highest level of residual activity on cats against the Kansas 1 flea strain.

Therapy of tungiasis: a double-blinded randomized controlled trial with oral ivermectin

Tungiasis is an ectoparasitosis causing considerable pathology in endemic areas. Standard therapy consists of removing the embedded parasite with a sterile needle. There is no effective chemotherapy at hand. To fill this gap, a double-blinded randomized controlled trial with oral ivermectin was conducted. A total of 54 individuals (27 in the placebo group, 27 in the ivermectin group) was followed up for seven days. They presented a total of 192 lesions. Patients received either ivermectin (300 microg/kg body weight at a single dose, repeated after 24 h) or placebo. Outcome measures included the clinical stage of lesion, presence of erythema, pain, itching, signs of viability of the parasite, and total lysis of flea. The ratio of fleas with total lysis per total number of fleas was slightly higher in the ivermectin group; however, this difference was not statistically significant. There was no significant difference in any of the other outcome measures between the treatment and the placebo group. The results show that oral ivermectin is without any clinically significant efficacy against embedded sand fleas at the dose given.

Nodulisporic acids D-F: structure, biological activities, and biogenetic relationships

Nodulisporic acids D, E, and F are the newest members of a family of nontremorogenic indole-diterpenoids that are potent, orally bioavailable, antiflea agents derived from a fungus belonging to the genus Nodulisporium. The four members of the D series are each devoid of an isoprene residue that is present at C-26 in the three nodulisporic acids described originally (the A series). Nodulisporic acid E (11a) has a simpler structure, which lacks not only the isoprene residue at C-26 but also two that form the A/B rings. Nodulisporic acid F is the simplest of all nodulisporic acids and is devoid of all three isoprene residues of the indole unit; as such, it represents the earliest biosynthetic intermediate in this series. A biogenetic grid based on mutation studies is proposed that encompasses all the known nodulisporic acids. Structure-activity relationships of the known natural nodulisporic acids have been elucidated. Within a series the most active compound possesses a dienoic acid chain, and overall, the end product of the biogenetic grid, i.e., nodulisporic acid A, exhibits the most potent antiflea activity. Additionally, the stereochemistries of C-3' ' and C-4' ' of nodulisporic acid D(2) and therefore of nodulisporic acids A(2), B(2), and C(2) have been assigned.