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Managed populations of honey bees (Apis mellifera Linnaeus; Hymenoptera: Apidae) are regularly exposed to infectious diseases. Good hive management including the occasional application of antibiotics can help mitigate infectious outbreaks, but new beekeeping tools and techniques that bolster immunity and help control disease transmission are welcome. In this review, we focus on the applications of beneficial microbes for disease management as well as to support hive health and sustainability within the apicultural industry. We draw attention to the latest advances in probiotic approaches as well as the integration of fermented foods (such as water kefir) with disease-fighting properties that might ultimately be delivered to hives as an alternative or partial antidote to antibiotics. There is substantial evidence from in vitro laboratory studies that suggest beneficial microbes could be an effective method for improving disease resistance in honey bees. However, colony level evidence is lacking and there is urgent need for further validation via controlled field trials experimentally designed to test defined microbial compositions against specific diseases of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America.)

Beekeeping is a widespread activity in Argentina, mainly producing honey that has gained both national and international recognition. There are more than 3,000,000 hives in the country, mainly concentrated in Buenos Aires Province (approximately 1,000,000 hives). In recent decades, worrying rates of hive loss have been observed in many countries around the world. In Latin America, the estimated loss of hives is between 13% (Peru and Ecuador) and 53% (Chile). Argentina had annual losses of 34% for the period of October 1, 2016 to October 1, 2017. The causes of these losses are not clear but probably involve multiple stressors that can act simultaneously. One of the main causes of loss of bee colonies worldwide is infestation by the ectoparasitic mite Varroa destructor in combination with viral infections. To date, 10 viruses have been detected that affect honey bees (Apis mellifera) in Argentina. Of these, deformed wing virus, sacbrood virus, acute bee paralysis virus, chronic bee paralysis virus, and Israeli acute bee paralysis can be transmitted by mites. Deformed wing virus and the AIK complex are the viruses most often associated with loss of hives worldwide. Considering that bee viruses have been detected in Argentina in several hymenopteran and non-hymenopteran insects, these hosts could act as important natural reservoirs for viruses and play an important role in their dispersal in the environment. Further studies to investigate the different mechanisms by which viruses spread in the environment will enable us to develop various strategies for the control of infected colonies and the spread of viruses in the habitat where they are found.

Lotmaria passim (Kinetoplastea) is considered the most prevalent as well as the most virulent trypanosomatid associated to the European honey bee Apis mellifera. We used qPCR to screen for the presence of this parasite in 57 samples from ten Argentinian provinces, and were able to detect its presence throughout most of the country with 41% of the samples testing positive. In a retrospective analysis, we detected L. passim in 73% of honey bee samples from 2006 showing that this flagellate has been widely present in Argentina for at least ~15 years. Additionally, three primer sets for L. passim detection were compared, with the pair that produced smallest PCR product having the best detection capability. Finally, we also found L. passim DNA in 100% (n = 6) of samples of the mite Varroa destructor. The role of this ectoparasite in the lifecycle of Lotmaria, if any, remains unrevealed., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Vector control is the most effective method to prevent transmission of Chagas disease. Control is mostly made through chemical insecticides although they have negative impact on wild pollinators, such as bees. Reducing pesticide use through biological alternatives could minimize the damage to these beneficial insects. Triatoma virus (TrV) is a pathogen able to kill triatomines and thus a valid candidate to be used as biological control agent. In this study we evaluate the capacity of TrV to infect an important beneficial insect (Apis mellifera) as well as a plague insect (Aedes aegypti). Results indicate that TrV does not infect the bees or mosquitoes tested in this study. The possible specificity of TrV for kissing bugs reinforces the possible use of TrV as a biological control agent for triatomines., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Nowadays several invertebrate pollinators of crops and wild plants are in decline as result of multiple and, sometimes, unknown factors; among them, the modern agricultural practices, pests and diseases are postulated as the most important factors. Bees of the genus Xylocopa are considered effective pollinators of passion fruit crops in tropical regions, as well as important pollinators in wild plants, but these bees are attacked by several pathogens that affect different stages in their life cycle. The fungal species of the genus Ascosphaera are commonly associated with social and solitary bee larvae causing chalkbrood disease., Aims: The aim of the present study was to demonstrate the presence of Ascosphaera apis affecting larvae of Xylocopa augusti in South America., Methods: For this purpose, A. apis was isolated from affected larvae in YGPSA medium. Final identification was run out by three techniques: (1) Microscopic examination of the hyphae and sizes of the fruiting bodies; (2) Mating test, and specific sexual compatibility test, and (3) PCR detection, using specific primers., Results: This study demonstrates for the first time the presence of A. apis affecting larvae of X. augusti in South America., Conclusions: The evidence of A. apis affecting the larvae of X. augusti, and the fact that the sharing of pathogens between different bee species has been underestimated, suggests the need for further epidemiological studies in order to determine not only the prevalence of this pathogen among wild pollinators, but also its relationship to the sudden collapse of honey bee colonies in this region., (Copyright © 2014 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.)

Honey bee mortality is a serious problem that beekeepers in Argentina have had to face during the last 3 years. It is known that the consequence of the complex interactions between environmental and beekeeping parameters added to the effect of different disease agents such as viruses, bacteria, fungi and parasitic mites may result in a sudden collapse of the colony. In addition, multiple viral infections are detected frequently concomitantly in bee colonies. The aim of this study was to establish a multiplex polymerase chain reaction method for rapid and simultaneous detection of the most prevalent bee viruses. This multiplex PCR assay will provide specific, rapid and reliable results and allow for the cost effective detection of a particular virus as well as multiple virus infections in a single reaction tube. This method could be a helpful tool in the surveillance of the most frequently found bee viruses and to study the dynamics and the interactions of the virus populations within colonies., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Honey bee mortality has recently been associated with Israeli acute paralysis virus (IAPV), a proposed etiological agent for a new syndrome known as Colony Collapse Disorder. Bees infected with this virus show shivering wings, progress into paralysis, and finally die outside the hive. During the last years, honey bee mortality became a serious problem for Argentinean beekeepers. We herein report the preliminary results of a survey carried out to detect IAPV in samples taken from several Argentine provinces, by using a reverse transcription Polymerase Chain Reaction assay. Our data indicate the existence of high frequency of IAPV in asymptomatic hives of Argentina.

American Foulbrood (AFB) of honeybees (Apis mellifera L.), caused by the Gram-positive bacterium Paenibacillus larvae is one of the most serious diseases affecting the larval and pupal stages of honeybees (A. mellifera L.). The aim of the present work was to asses the response of 23 strains of P. larvae from diverse geographical origins to tilmicosin, a macrolide antibiotic developed for exclusive use in veterinary medicine, by means of the minimal inhibitory concentration (MIC) and the agar diffusion test (ADT). All the strains tested were highly susceptible to tilmicosin with MIC values ranging between 0.0625 and 0.5 microg ml(-1), and with MIC(50) and MIC(90) values of 0.250 microg ml(-1). The ADT tests results for 23 P. larvae strains tested showed that all were susceptible to tilmicosin with inhibition zones around 15 microg tilmicosin disks ranging between 21 and 50mm in diameter. Oral acute toxicity of tilmicosin was evaluated and the LD(50) values obtained demonstrated that it was virtually non-toxic for adult bees and also resulted non-toxic for larvae when compared with the normal brood mortality. Dosage of 1000 mg a.i. of tilmicosin applied in a 55 g candy resulted in a total suppression of AFB clinical signs in honeybee colonies 60 days after initial treatment. To our knowledge, this is the first report of the effectiveness of tilmicosin against P. larvae both in vitro and in vivo.

Paenibacillus larvae is the causal agent of American Foulbrood (AFB) disease, the most virulent bacterial disease of honeybee (Apis mellifera L.) brood. Oxytetracycline is the main antibiotic used for prevention and control of AFB. Using the polymerase chain reaction, isolates were screened for the presence of the tetracycline resistance tet(K) and tet(L) determinants. Four isolates (5%), which correlated with the Tc-resistant phenotypes, were found to carry the tet(K) determinant, whereas none carried the tet(L) determinant. P. larvae cells were also screened for the presence of extrachromosomal DNA and evidence obtained that tetracycline resistance is plasmid-encoded. A few P. larvae isolates were found to be able to transfer the tet(K) determinant to Bacillus subtilis, suggesting that a conjugation mechanism may be involved in the transfer of the tetracycline-resistant phenotype. Minimum inhibitory concentrations to tetracycline were determined for 75 isolates of P. larvae from different geographical origins and found to range between 0.062 and 128 microg tetracyclineml(-1), with MIC(50) and MIC(90) values of 1 and 4, respectively. According to results from P. larvae populations, isolates could be considered as susceptible when their MICs were <4, intermediate for MICs values 4-8 and resistant for MICs > or = 16. To our knowledge, this is the first report of Tc(r)Paenibacillus species carrying a tet(K) gene, and also the first record of P. larvae strains carrying tet(K) determinants and its correlation with the presence of extrachromosomal DNA.

The bacterium Paenibacillus larvae, the causative agent of American foulbrood disease of honeybee larvae, occurs throughout the world and is found in many beekeeping areas of Argentina. The potential as biocontrol agents of antagonic aerobic spore-forming bacteria isolated from honey samples and other apiarian sources were evaluated. Each isolate was screened against one strain of Paenibacillus larvae (ATCC 9545) by using a perpendicular streak technique. Ten randomly selected bacterial strains from the group that showed the best antagonistic effect to P. larvae ATCC 9545 were selected for further study. These were identified as Bacillus subtilis (m351), B. pumilus (m350), B. licheniformis (m347), B. cereus (mv33), B. cereus (m387), B. cereus (m6c), B. megaterium (m404), Brevibacillus laterosporus (BLAT169), B. laterosporus (BLAT170), and B. laterosporus (BLAT171). The antagonistic strains were tested against 17 P. larvae strains from different geographical origins by means of a spot test in wells. The analysis of variance and posterior comparison of means by Tukey method (P < 0.01) showed that the best antagonists were B. megaterium (m404), B. licheniformis (m347), B. cereus (m6c), B. cereus (mv33), and B. cereus (m387).

The minimal inhibitory concentrations (MICs) of tylosin were determined to 67 strains of Paenibacillus larvae subsp. larvae, the causal agent of American Foulbrood (AFB) disease, from different geographical origins. MIC values obtained ranged from 0.0078 to 0.5 microg/ml. These very low values imply that no resistance to tylosin was found in any isolate of the Foulbrood pathogen. The measurement of diseased larvae with AFB-clinical symptoms in three different field studies demonstrated that tylosin treatment could be effective in vivo. No negative effects in colonies were noted at any dosage rates or forms of application. These studies demonstrate that tylosin, as tartrate, can be used to treat AFB in honeybee colonies.

In the La Plata Horticultural Belt (CHP, in Spanish), bee viruses were searched for the first time in green bug Nezara viridula (Hemiptera: Pentatomidae). The presence of the Israeli acute paralysis virus (IAPV) was detected using PCR technique. These results would allow to infer that knowledge of viral infections in insects could be of great importance since they could act as viral reservoirs, resulting in the spilling of pathogens to honey bees and other pollinators. This study made it possible to detect IAPV for the first time in N. viridula. Future studies are needed to understand the ecology of these viruses in arthropod communities of CHP and to determine the role that green bugs play as possible reservoirs of these viruses in the environment. [ABSTRACT FROM AUTHOR]

Invasive parasites are major threats to biodiversity. The honey bee ectoparasite, Varroa destructor , has shifted host and spread almost globally several decades ago. This pest is generally considered to be the main global threat to Western honey bees, Apis mellifera , although the damages it causes are not equivalent in all its new host's populations. Due to the high virulence of this parasite and the viruses it vectors, beekeepers generally rely on acaricide treatments to keep their colonies alive. However, some populations of A. mellifera can survive without anthropogenic mite control, through the expression of diverse resistance and tolerance traits. Such surviving colonies are currently found throughout the globe, with the biggest populations being found in Sub-Saharan Africa and Latin America. Recently, genetic differences between mite populations infesting surviving and treated A. mellifera colonies in Europe were found, suggesting that adaptations of honey bees drive mite evolution. Yet, the prevalence of such co-evolutionary adaptations in other invasive populations of V. destructor remain unknown. Using the previous data from Europe and novel genetic data from V. destructor populations in South America and Africa, we here investigated whether mites display signs of adaptations to different host populations of diverse origins and undergoing differing management. Our results show that, contrary to the differences previously documented in Europe, mites infesting treated and untreated honey bee populations in Africa and South America are genetically similar. However, strong levels of genetic differentiation were found when comparing mites across continents, suggesting ongoing allopatric speciation despite a recent spread from genetically homogenous lineages. This study provides novel insights into the co-evolution of V. destructor and A. mellifera , and confirms that these species are ideal to investigate coevolution in newly established host-parasite systems. • Varroa destructor parasites show genetic differences across novel host populations. • Differences can be found in some sympatric populations with different management. • Comparing allopatric populations also revealed ongoing genetic differentiation. • Interactions with distinct host populations appear to drive V. destructor evolution. [ABSTRACT FROM AUTHOR]