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Drongen, Belgium

Ketzis J.K.,Ross University School of Medicine | Clements K.,Ross University School of Medicine | Honraet K.,Oystershell Laboratories
Parasitology Research | Year: 2014

Head lice (Pediculus humanus capitis) remain a nuisance, predominantly in school age children. Despite the availability of pediculicidal products, children, after treatment, easily become re-infested if the outbreak has not been controlled on a class or school level. Lice repellents and re-infestation deterrents have been developed to protect children post-treatment. In vitro assays, which are used to evaluate the performance of these products, have limited correlation to in vivo efficacy. In this study, a chicken model was developed as an alternative to in vitro models, more closely mimicking the in vivo situation of children at school. Chickens with natural infestations of Menopon spp. and Menacanthus spp. were divided into three groups and co-housed for 23 h: Group 1 was treated with a commercial product designed to kill lice and protect from re-infestation (Oystershell Laboratories); group 2 was used to assess lice re-population onto lice-free, untreated chickens; and group 3, the seeder group, consisted of lice-infested chickens. The chickens were examined for lice before and at regular intervals after treatment. The group 1 chickens had an average of 40 lice pre-treatment, 0 lice post-treatment and did not become re-infested during the 23-h period. Lice were slow to re-populate the group 2 chickens but were seen 3 h after co-housing with an average of 6 lice each at the end of the study. Group 3 chickens maintained their lice throughout the study (average of 32 at end of study). Based on this study, chickens can be used as a model to test the performance of lice repellents and re-infestation deterrents. © 2014 Springer-Verlag.

Boeve J.-L.,Royal Belgian Institute Of Natural Sciences | Eertmans F.,Oystershell Laboratories | Adriaens E.,Bellemdorpweg 95 | Rossel B.,Oystershell Laboratories
Insects | Year: 2016

Vespid wasps are ecologically beneficial predators of insects but their stings also pose a human health risk. Current control methods based on killing vespids are suboptimal. Here, the repellent effect against Vespula vulgaris of a 20% icaridin skin lotion was evaluated under field conditions. An experimental setup was designed in which six artificial skin pieces (10 × 10 cm) were video-recorded for 1 h, to count each min the numbers of flying and feeding vespids. Prior to monitoring, five pieces were successively smeared with 2 mg of cream per cm2, in 30 min intervals, from t = -120 min to 0. The sixth sheet remained untreated to serve as a control. One milliliter of an attractant, fruit jam, was deposited on each of the six surfaces at t = 0. The control surface was free of any flying or feeding vespid during an average period of 25 min, whereas the other five surfaces (treated at t = -120, -90, -60, -30, and 0 min) remained vespid-free for 39, 40, 45, 49, and 51 min, respectively. The skin lotion remained significantly active for at least 2 h. The experimental methodology is adjustable and allows the study of repellents against vespids in semi-natural conditions. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

Boeve J.-L.,Royal Belgian Institute Of Natural Sciences | Honraet K.,Oystershell Laboratories | Rossel B.,Oystershell Laboratories
Insects | Year: 2014

Vespid wasps are ecologically beneficial, but they can be a nuisance and dangerous to people due to their tendency to sting. Here, the aim was to screen samples of volatiles (i.e., essential oils and pure chemicals) for their repellency against wasps. The number of wasps (mainly Vespula vulgaris) present in a glass box with attractant and 5 μL sample was compared to the number of wasps in a similar box with attractant only. Both boxes were connected to a large glass container harboring 18-35 wasps. Among 66 tested samples, some essential oils from Lamiaceae and Asteraceae, as well as some pure natural compounds such as the monoterpenes (-)-terpinen-4-ol and isopulegol showed a significant repellency against vespids. Our results corroborate the potential of (mixtures of) volatiles in repelling these insects. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Yoon K.S.,Southern Illinois University at Edwardsville | Ketzis J.K.,Southern Illinois University at Edwardsville | Ketzis J.K.,Ross University School of Medicine | Andrewes S.,University of Massachusetts Amherst | And 5 more authors.
Journal of Medical Entomology | Year: 2015

The human head louse is a cosmopolitan ectoparasite and frequently infests many people, particularly school-age children. Due to widespread pyrethroid resistance and the lack of efficient resistance management, there has been a considerable interest in the protection of uninfested people and prevention of reinfestation by disrupting lice transfer. In this study, two nonclinical model systems (in vitro and in vivo) were used to determine the efficacy of the infestation deterrents, Elimax lotion and Elimax shampoo, against human head lice or poultry chewing lice, respectively. With in vitro assessments, female head lice exhibited significantly higher avoidance responses to hair tufts treated with either of the test formulations, which led to significantly higher ovipositional avoidance when compared with female lice on control hair tufts. Additionally, both formulations were determined to be competent infestation deterrents in a competitive avoidance test in the presence of a known attractant (head louse feces extract). In in vivo assessments using a previously validated poultry model, Elimax shampoo was determined to be an efficacious deterrent against poultry chewing lice within Menopon spp. and Menacanthus spp. © The Authors 2015.

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