Short-term group fission processes in macaques: a social networking approach

Living in groups necessarily involves a certain amount of within-group competition for food. Group members may have different motivations, implying the reaching of a consensus to stay cohesive. In some cases individuals fail to reach a common decision and the group splits; this can be temporary, as seen in fission-fusion dynamics, or even irreversible. Most studies on fission-fusion dynamics published to date have focused on the influence of environmental constraints on sub-grouping patterns, but little is known about how social relationships affect individual choices for sub-groups. In this study, we used an agent-based model to understand the mechanisms underlying group fission in two semi-free-ranging groups of macaques: one group of Tonkean macaques (Macaca tonkeana) and one of rhesus macaques (M. mulatta). The results showed that sub-grouping patterns were mainly influenced by affiliative relationships. Moreover, the species-specific social style appeared to affect the probability of choosing a particular sub-group. In the tolerant Tonkean macaques, mechanisms underlying sub-grouping patterns resembled anonymous mimetism, while in the nepotistic rhesus macaques, kinship influenced the mechanisms underlying group fissions. As previous studies have shown, fission-fusion society may be a way to avoid social conflicts induced either by food or by social competition.

The impact of moving to a novel environment on social networks, activity and wellbeing in two new world primates

Among the stressors that can affect animal welfare in zoos, the immediate effect of relocation to a novel environment is one that has received little attention in the literature. Here, we compare the social network, daily activity and the expression of stress-related behavior in capuchins (Cebus apella) and squirrel monkeys (Saimiri sciureus) before and just after they were relocated to a new enriched enclosure. Results showed similar immediate responses to the move in the two species. Both showed a substantial increase in the time spent resting and spent more time in the highest and "safest" part of their enclosure after relocation. Both capuchins and squirrel monkeys spent significantly more time in close proximity to other group members after relocation, compared to before. In squirrel monkeys, the structure of the social network, which was initially correlated to affiliation, was no longer so after the move. In capuchins, the network analysis showed that individuals regrouped by age, with the youngsters who were potentially more affected by stress being in the center of the network. Social network analysis helped to achieve a more complete picture of how individuals were affected by relocation. We suggest that this type of analysis should be used alongside traditional methods of observation and analysis to encompass the most complex aspects of animal behavior in times of stress and to improve welfare.

Evaluation of the long-term efficacy and safety of an imidacloprid 10%/flumethrin 4.5% polymer matrix collar (Seresto®) in dogs and cats naturally infested with fleas and/or ticks in multicentre clinical field studies in Europe

Background

The objective of these two GCP multicentre European clinical field studies was to evaluate the long-term efficacy and safety of a new imidacloprid/flumethrin collar (Seresto^®, Bayer AnimalHealth, Investigational Veterinary Product(IVP)) in dogs and cats naturally infested with fleas and/or ticks in comparison to a dimpylat collar ("Ungezieferband fuer Hunde/fuer Katzen", Beaphar, Control Product (CP)).

Methods

232 (IVP) and 81 (CP) cats and 271(IVP) and 129 (CP) dogs were treated with either product according to label claims and formed the safety population. Flea and tick counts were conducted in monthly intervals for up to 8 months in the efficacy subpopulation consisting of 118 (IVP) + 47 (CP) cats and 197 (IVP) + 94 (CP) dogs. Efficacy was calculated as reduction of infestation rate within the same treatment group and statistically compared between the two treatment groups.

Results

Preventive efficacy against fleas in cats/dogs varied in the IVP group between 97.4%/94.1% and 100%/100% (overall mean: 98.3%/96.7%) throughout the 8 month period and in the CP group between 57.1%/28.2% and 96.1%/67.8% (overall mean: 79.3%/57.9%). Preventive efficacy against ticks in cats/dogs varied in the IVP group between 94.0%/91.2% and 100%/100% (overall mean: 98.4%/94.7%) throughout the 8 month period and in the CP group between 90.7%/79.9% and 100%/88.0% (overall mean: 96.9%/85.6%). The IVP group was statistically non-inferior to the CP group, and on various assessment days, statistical superiority was proven for flea and tick count reduction in dogs and cats. Both treatments proved to be safe in dogs and cats with mainly minor local observations at the application site. There was moreover, no incidence of any mechanical problem with the collar in dogs and cats during the entire study period.

Conclusions

The imidacloprid/flumethrin collar proved to reduce tick counts by at least 90% and flea counts by at least 95% for a period of at least 7-8 months in cats and dogs under field conditions. Therefore, it can be used as sustainable long-term preventative, covering the whole flea and tick season.

From the first intention movement to the last joiner: macaques combine mimetic rules to optimize their collective decisions

Mechanisms related to collective decision making have recently been found in almost all animal reigns from amoebae to worms, insects and vertebrates, including human beings. Decision-making mechanisms related to collective movements-including pre-departure and joining-have already been studied at different steps of the movement process, but these studies were always carried out separately. We therefore have no understanding of how these different processes are related when they underlie the same collective decision-making event. Here, we consider the whole departure process of two groups of Tonkean macaques (Macaca tonkeana), using a stochastic model. When several exclusive choices are proposed, macaques vote and choose the majority. Individuals then join the movement according to a mimetism based on affiliative relationships. The pre-departure quorum and the joining mimetic mechanism are probably linked, but we have not yet identified which transition mechanism is used. This study shows that decision-making related to macaque group movements is governed by a quorum rule combined with a selective mimetism at departure. This is the first time that transition mechanisms have been described in mammals, which consequently helps understand how a voting process leads to social amplification. Our study also provides the first complete proof that there is continuity in the decision-making processes underlying collective movements in mammals from the first intention movement right through to the last joiner.

Comparative evaluation of the prophylactic activity of a slow-release insecticide collar and a moxidectin spot-on formulation against Thelazia callipaeda infection in naturally exposed dogs in France

Background

The relative efficacy of a collar containing 10% imidacloprid and 4.5% flumethrin (Seresto®, Bayer HealthCare Animal Health) and a spot on formulation containing 10% imidacloprid and 2.5% moxidectin (Advocate®, Bayer HealthCare Animal Health) was evaluated as a control measure to prevent canine thelaziosis in dogs in an endemic area of France.

Findings

Ninety-six privately-owned dogs were enrolled in the multicentre, controlled study. Before summer (the period of transmission by fruit flies), dogs were allocated to one of three groups: Group A (n = 36)- treated once with a collar containing 10% imidacloprid and 4.5% flumethrin; Group B (n = 33)- treated every month for 8 months with a spot-on containing imidacloprid 10% and moxidectin 2.5%; and Group C (n = 27)- untreated control animals. Dogs were regularly subjected to ocular examination in order to assess Thelazia callipaeda infection. During the trial, T. callipaeda nematodes were detected in 12 (33%) collared dogs (group A) whereas no eyeworm could be found in dogs who received a monthly spot on application of moxidectin (group B). In the control group, 8 (30%) dogs became infected.

Conclusions

The monthly application of a spot on formulation containing 10% imidacloprid and 2.5% moxidectin was shown to be highly effective in preventing T. callipaeda infection in a population of dogs living in an endemic area in France. On the contrary, the slow-release collar tested in this study did not display any protection against canine thelaziosis.

Efficacy of a combination of imidacloprid 10%/moxidectin 2.5% spot-on (Advocate® for dogs) in the prevention of canine spirocercosis (Spirocerca lupi)

The nematode Spirocerca lupi is a major canine parasite in warm regions of the world, classically causing parasitic nodules in the esophagus, aortic aneurysms, and spondylitis. This study evaluated the preventive efficacy of monthly treatment with imidacloprid 10%/moxidectin 2.5% spot-on (Advocate® for dogs) administered over a period of 9 months in young dogs naturally exposed to S. lupi on Réunion island. One hundred and twelve puppies, aged from 2.0 to 4.0 months and with a negative spirocerca fecal examination at inclusion, completed the study. They were randomly allocated to two groups. Group A puppies (n = 58) received nine spot-on treatments with Advocate® at the minimum dose of 2.5 mg moxidectin/kg bw at monthly intervals. Control group B puppies (n = 54) received no treatment for S. lupi. During the study, regular clinical and fecal examinations were performed, as was final upper gastrointestinal endoscopy. Endoscopy showed that 19 dogs from group B had spirocerca nodules, corresponding to a prevalence of 35.2% in dogs aged 12 to 14 months. In contrast, only one dog from group A had a nodule, corresponding to a preventive efficacy of 94.7% (p < 0.0001). None of the 378 fecal examinations were positive for spirocerca. This study confirms a high prevalence of canine spirocercosis on Réunion and shows that infestation occurs in very young puppies. Furthermore, it demonstrates that monthly spot-on administration of a combination of imidacloprid 10%/moxidectin 2.5% (Advocate® for dogs) in puppies starting at the age of 2 to 4 months achieves effective and safe prevention of canine spirocercosis.

Efficacy and safety of the combination imidacloprid 10 % / moxidectin 1.0 % spot-on (Advocate(®) spot-on for small cats and ferrets) in the treatment of ear mite infection (Otodectes cynotis) in ferrets

In this study, the efficacy and safety of a treatment with the combination imidacloprid 10 %/ moxidectin 1.0 % spot-on (Advocate(®) spot-on for small cats and ferrets) was tested in 39 ferrets naturally infested with ear mites (Otodectes cynotis). The study was performed as a multicentre, non-randomised, non-controlled (all study animals were treated) and non-blinded clinical field study in two French veterinary practices. Four visits (day (D) 0 = inclusion and first treatment, D14 = second treatment, D28 = possible third treatment, D56 = termination) were planned. The dosage was one pipet per ferret (designed for cats weighing up to 4 kg, corresponding to a dose of moxidectin ranging from 2.2 to 5 mg/kg body weight) two or three times at 14-days intervals (at D0, D14 and possibly D28 depending on the parasitological examination of the ears at D28). The main efficacy criterion was the absence of the parasite (all stages incl. eggs, larvae, nymphs and adults) from ear scrapings by microscopic examination. At D28 after two treatments (D0 and D14), 76.9 % (30/39) of animals were cured. Only 23 % (9/39) needed a third treatment. At day 56, 100 % were cured. Local symptoms (inflammation and pruritus) were consistently improved (50.6 % improvement at D14, 81.0 % at D28 and 97.9 % at D56) as well as the abnormal cerumen production (14.7 % improvement at D14, 77.7 % at D28 and 100.0 % at D56). No general symptoms were noticed during the study (general health and skin aspect). Advocate(®) spot-on for small cats and ferrets is an effective and safe treatment for ear mite infection in ferrets. Two or three treatments administered in 14-days intervals to ferrets infested with ear mites provided 100 % parasitological cure on D56.

Evaluation of the anti-feeding and insecticidal effects of a topically administered combination of imidacloprid and permethrin (Advantix®) against Phlebotomus (Larroussius) perniciosus (Newstead, 1911) in dogs following monthly administration

BACKGROUND

Two laboratory experiments (Studies 1 and 2) were conducted to confirm the efficacy of an imidacloprid and permethrin combination (Advantix® Spot-on, Bayer) to repel and kill Phlebotomus (Larroussius) perniciosus sand flies when applied once a month topically to dogs.

METHODS

Both studies compared dogs treated with a combination containing 100 mg/ml imidacloprid + 500 mg/ml permethrin (Advantix® Spot-on, Bayer) to placebo treated dogs. The treatments were applied topically on Day -28 (Study 2) and Day 0 (Studies 1 and 2). Sand fly exposures with 80 unfed females were performed before the first treatment for allocation purposes and post-treatment on study days (SDs) 1, 7, 14, 21 and 28 (following first or second monthly treatment for Studies 1 and 2, respectively). After 60 min, sand flies were assessed for mortality and engorgement status.

RESULTS

Repellent evaluation (anti-feeding effect) on all days post-infestation showed efficacies that ranged between 88.1-99.3% during the first month and 92.2-98.9% during the second. Analyses of the comparison of fed sand fly counts for each treatment group resulted in a highly significant reduction (P < 0.0001) at all post-infestation time points for those dogs treated with Advantix®. A significant (P < 0.0001 for all time points) insecticidal effect was equally demonstrated. No treatment related adverse events were observed during the study.

CONCLUSIONS

In the present studies Advantix® Spot-on demonstrated to be safe and to provide excellent four-week sand fly (P. perniciosus) repellency of ≥88.1% and ≥92.2% after a first and second monthly treatment, respectively. A significant insecticidal effect was also observed.

[Ecstasy and its "counterparts"]

RISK AWARENESS: Use of psychostimulants is spreading in France, particularly at "techno" dances. The generic term "ecstasy" covers a wide variety of molecules with variable formulations. The situation is a true public health problem, generally concerning very young subjects who must be informed of the risks involved. Knowledge of the chemical makeup of the products currently used is needed to provide valid information and reduce risks.

CHEMICAL ANALYSIS

Two types of chemical analysis are used for rapid controls. A coloration test is used by the Rave mission implemented by "Médecins du Monde". More elaborate analysis methods are used to identify the active substances and quantify the compounds in the different "tablets".

FINDINGS

Rapid controls give a means of quickly identifying samples containing methylenedioxyamphetamines and distinguishing them from other samples which may contain any number of substances with unknown toxicity. A precise analysis of 73 samples has shown highly variable compositions with 22% actually containing methylenedioxyamphetamines.

PREVENTION

Precise analytical knowledge of the drugs circulating in "techno" dances has revealed the extreme danger of a large number of the substances used. A continuous control of ongoing consumption is required to correctly warn the users and reduce risk.