Propolis Consumption Reduces Nosema ceranae Infection of European Honey Bees (Apis mellifera).

Nosema ceranae is a widespread obligate intracellular parasite of the ventriculus of many species of honey bee (Apis), including the Western honey bee Apis mellifera, in which it may lead to colony death. It can be controlled in A. mellifera by feeding the antibiotic fumagillin to a colony, though this product is toxic to humans and its use has now been banned in many countries, so in beekeeping, there exists a need for alternative and safe products effective against N. ceranae. Honeybees produce propolis from resinous substances collected from plants and use it to protect their nest from parasites and pathogens; propolis is thought to decrease the microbial load of the hive. We hypothesized that propolis might also reduce N. ceranae infection of individual bees and that they might consume propolis as a form of self-medication. To test these hypotheses, we evaluated the effects of an ethanolic extract of propolis administered orally on the longevity and spore load of experimentally N. ceranae-infected worker bees and also tested whether infected bees were more attracted to, and consumed a greater proportion of, a diet containing propolis in comparison to uninfected bees. Propolis extracts and ethanol (solvent control) increased the lifespan of N. ceranae-infected bees, but only propolis extract significantly reduced spore load. Our propolis extract primarily contained derivatives of caffeic acid, ferulic acid, ellagic acid and quercetin. Choice, scan sampling and food consumption tests did not reveal any preference of N. ceranae-infected bees for commercial candy containing propolis. Our research supports the hypothesis that propolis represents an effective and safe product to control N. ceranae but worker bees seem not to use it to self-medicate when infected with this pathogen.

Seroprevalence and risk factors of Coxiella burnetii infection in cattle in northeast Algeria.

A cross-sectional study was conducted to determine the seroprevalence and the risk factors associated with C. burnetii infection in cattle in the state of Setif in northeastern Algeria from March 2016 to April 2018. A total of 678 cows animals aged at least 24 months and belonging to 90 herds were randomly selected. A serum sample from each cow was tested for antibodies against C. burnetii using an indirect enzyme-linked immunosorbent assay (ELISA). A structured questionnaire focusing on risk factors for C. burnetii infection was administered to farm owners involved in the study. The individual animal prevalence was 11.36% (77/678) (95%CI 8.97-13.75%), the herd prevalence was 45.56% (41/90) (95%CI 35.27-55.84%), and the within-herd prevalence ranged from 9.09 to 57.14% (mean 23.71%; Q1 11.11%, Q2 or median 20%, Q3 30%). Multivariable logistic regression analysis revealed that contact with other herds (odds ratio (OR) 1.95, 95 CI 1.12-3.42) and purchased animals (OR 2.05, 95 CI 1.14-3.68) was identified as risk factors for seropositivity to C. burnetii, while the use of disinfectants (OR 0.32, 95 CI 0.14-0.72) was identified as protective factor. The results from the present study indicate that C. burnetii is circulating into cattle herds in the region of Setif in Northeastern of Algeria. It is recommended to implement good hygienic practices and measures of biosecurity to reduce the spread of infection between cattle herds and possible exposure of humans.

Validation of a one-step PCR assay for the molecular identification of Echinococcus granulosus sensu stricto G1-G3 genotype.

The Italian National Reference Center for Echinococcosis (CeNRE, Sassari, Italy) set up a diagnostic protocol of "one-step-PCR" useful for the detection of E. granulosus sensu stricto (E.g.s.s.) and the identification of its genotype (G1-G3). The purpose of this work was to perform the validation of the "PCR E.g.s.s." method. The procedures were performed employing the criteria of the World Organization for Animal Health as well as of the Italian Accreditation Body (ACCREDIA) based on the Regulation UNI CEI EN ISO/IEC 17025. Positive DNA samples belonging to E. granulosus, E. ortleppi, E. multilocularis, E. canadensis species were used for the experiments. Analytical specificity evidenced primer pairs Cal (Calreticulin l gene of 1001 bp) with an specificity higher respect to Ef1 (Elongation-Factor 1 Alpha gene of 706 bp) and NAD (Dehydrogenase-subunit 1 gene of 219 bp). The analytical sensitivity presented the capability to detect a very low amount of parasite DNA corresponding to a concentration of 12.5 pg/µl; accuracy and precision related to the operator performance, along with repeatability and reproducibility, evidenced high concordance among results and demonstrated an excellent κ values of Cohen. According to the good performance related to the evaluated parameters, the method "PCR E.g.s.s." was suitable for the validation procedure, and consequently, to be undergone to the accreditation process. In conclusion, the results demonstrated an elevated robustness and reliable features of the "PCR E.g.s.s." able to perform a rapid diagnosis of E. granulosus in only "one step", hence, it is likely to avoid the sequencing step.

Feeding strategies and intraspecific competition in German yellowjacket (Vespula germanica).

The German yellowjacket (Vespula germanica) is an opportunist predator and a scavenger, whose eclectic diet also includes honey, brood, dead and live honey-bees. There is no evidence in this species of coordinated attacks against bees involving other conspecifics, although intraspecific competition has been already reported between two or more individuals during feeding. Our aim was to gain further knowledge on the feeding behavior of V. germanica in order to evaluate its role in an apiary. Sight observations of predation and necrophagy behaviors were carried out at the ground level near hives. We also investigated how intraspecific competition can influence the feeding display in this species. Our results confirm the major role of the German yellowjacket as a scavenger, because its diet is based mostly on bee carrions. Intraspecific competition during feeding was sometimes observed. When these events occurred, the interference of another wasp led to the bee escaping only in three cases. Our study also revealed that intraspecific competition events increase when the resource is fresh (predation vs necrophagy), and that the number of competing wasps was significantly higher when the food consisted of pupae and drones, compared to adult bees. When competition involved two individuals (the most frequent case), the winner was frequently the first wasp to reach the resource in both predation and necrophagy events. This suggests that the energy invested in foraging or predating activity and in defence of prey is usually rewarded.

The effects of raw propolis on Varroa-infested honey bee (Apis mellifera) workers.

Self-medication plays a major role in the behavioral defense against pathogens and parasites that animals have developed during evolution. The conditions defining this adaptive behavior are: (1) contact with the substance in question must be deliberate; (2) the substance must be detrimental to one or more parasites; (3) the detrimental effect on parasites must lead to increased host fitness. Recent studies have shown that A. mellifera colonies are able to increase resin foraging rates when infested by V. destructor, whereas further investigations are needed for evidence of parasite and host fitness. In order to understand whether Varroa-infested colonies could benefit from increasing levels of resin, we carried out laboratory bioassays to investigate the effects of propolis on the fitness of infested workers. The longevity and energetic stress of adult bees kept in experimental cages and artificially infested with the mite were thus monitored over time. At the same time, in vitro experiments were performed to study the contact effects of crude propolis on Varroa mites. Our results clearly demonstrate the positive effects of raw propolis on the lifespan of Varroa-infested adult bees. A low narcoleptic effect (19-22%) of raw propolis on phoretic mites after 5 h was also observed. In terms of energetic stress, we found no differences between Varroa-free and Varroa-infested bees in terms of the daily sucrose solution demand. Our findings seem to confirm the hypothesis that resin collection and propolis use in the hive represent an example of self-medication behavior in social insects.

Influence of mating disruption on the reproductive biology of the vine mealybug, Planococcus ficus (Hemiptera: Pseudococcidae), under field conditions.

BACKGROUND: Although mating disruption is increasingly being used to control the worldwide grapevine pest vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), its mode of action remains unclear. A 3-year field experiment was carried out to investigate the effects of mating disruption on the development and reproduction of the vine mealybug. The influence of mating disruption applied over consecutive years on the pest population density was also evaluated. RESULTS: The percentage of ovipositing females was significantly reduced in disrupted plots by 18.8-66.2%, depending on the year. The absence of ovipositing females in disrupted plots in the autumn of the second and third years indicates the effectiveness of mating disruption throughout the whole growing season. Mating disruption consistently prolonged the pre-oviposition period in all years by up to 12.5 days. CONCLUSION: Our findings provide new insights into the mechanisms underlying the pheromone-based control of the vine mealybug and indicate that the reduction of the pest population density is attributable to both a decrease and a delay in female mating. In addition, the population density of vine mealybugs under mating disruption decreased over the years, indicating that consecutive applications of this control strategy would significantly increase the effectiveness of control of the vine mealybug by mating disruption. © 2018 Society of Chemical Industry.

Molecular detection of spotted fever group rickettsiae in ticks from Ethiopia and Chad.

DNA extracted from 363 ticks collected in Ethiopia and 9 ticks collected in Chad, Africa were screened by PCR to detect DNA from spotted fever group rickettsiae. Fifteen ticks (4.1%) collected in Ethiopia and one tick (11%) collected in Chad tested positive when PCR targeting the gltA and ompA rickettsial genes was performed. PCR-positive products of the gltA and ompA genes were used for DNA sequencing. Rickettsia africae was detected in 12/118 Amblyomma lepidum and in 1/2 A. variegatum. Also, 2/12 Hyalomma marginatum rufipes collected in Ethiopia and one H. marginatum rufipes collected in Chad were positive for R. aeschlimannii. Our results confirm the previously reported presence of R. africae in Ethiopia and also show the first evidence of R. aeschlimannii in ticks collected in Ethiopia and Chad.