Archive for May 2015
By: Lynn Mirigian, PhD
One in every three bites of food we take can be attributed to the work of a honeybee, or less often, to another pollinator. Apples, almonds, avocados, and strawberries are just a few crops that require pollinators, but pollinator populations are seriously declining. The 70 billion dollar global (USA-15 billion) crop industry that is fueled by pollinators is being threatened by dwindling pollinator populations.1, 2 In addition, loss of pollinators may pose public health risks. In developing nations, for example, it is hypothesized that a decrease in pollinators could lead to an increase in Vitamin A deficiency which could double the risk of mortality from malaria, measles, and diarrhea.3 Because of the serious economic and public health consequences of pollinator population collapse, an inter-agency task force directed by President Obama has announced the National Strategy to Promote the Health of Honey Bees and Other Pollinators.
Honey bee colonies were first introduced to the US in the early 1600’s and are now commercialized. There are between 2,000-3,000 professional US beekeepers employed for both pollination services and to support honey production.1 In addition to honey bees, 4,000 wild bee species, as well as butterflies, bats, birds, and other animals function as pollinators in the US.4 Numerous species of bees live alone in isolation, but many key pollinators exist as a superorganism in a colony. The colony is supported by a queen, who mates with ~20 reproductive drones early in life to provide a lifetime supply of sperm, and the queen lays all of the eggs the colony needs for up to 4 years. The vast majority of bees produced in the colony are worker bees, following a career trajectory of hive and brood maintenance then foraging duties. Foraging bees collect pollen and nectar as a protein and carbohydrate source, respectively. Attracted to brightly colored flowers, bees travel from flower to flower, collecting food but also transferring pollen to facilitate plant reproduction (i.e. fruit formation). Colony success and survival is predicated on all members collectively working together. Over the past 3 decades, honey bee populations have dwindled for reasons only partially understood.
One challenge to healthy bee populations is habitat loss and reduced availability of diverse foraging and nesting resources. These problems likely arise from increased pesticide usage. Insecticides and herbicides are commonly used in commercial agriculture and are highly toxic to pollinators, such as honey bees. Herbicides can be harmful for bees’ survival, by killing valuable “weeds” that are both potential nesting sites and valuable food sources that improve pollen diversity necessary for bee health and proper nutrition. Besides herbicide usage, habitat transformation can also cause malnutrition, which affects gene expression in worker bees,5 and increases lethality to pesticides.6 Since specifics behind the ideal honey bee habitat and nutrition remain unknown, implementing large scale changes and policy is not yet realistic. Experiments are ongoing to determine whether buffer zones between commercial agriculture fields and bee colonies or planting tailored seed mixes to improve habitat will positively affect bee colony success.
Most relevant to honey bees, neonicotinoids are a class of insecticides used on rapeseed, which is used to make canola oil. Although neonicotinoids are coated onto seeds in an attempt to eliminate direct contact with pollinators, they can still affect bees in two ways. The insecticide dust created during planting kills the bee immediately upon exposure, and small amounts of the toxin remain in the nectar and pollen of the mature rapeseed plant. The toxicity of these trace amounts of neonicotinoids on bees has been hotly contested, demonstrating the need for further research. Research suggests that even small amounts of neonicotinoids can impact a bee’s brain function and prevent them from foraging well or being able to return home,7 however scientists still do not understand how much insecticide bees actually ingest and how often they are exposed to these chemicals in their native environments. In the absence of a more complete picture of bees’ experiences in their natural habitats, it is difficult to propose bee-safe farming insecticide practices.
Besides pesticide use and habitat transformation, arthropod pests, pathogens, and colony collapse disorder (CCD) represent additional factors underlie recent reductions in bee numbers. The Varroa destructor mite feeds on honeybee blood (hemolymph), grows its young on developing bees, and can increase bees’ susceptibility to viruses. As a potential protective mechanism, some bees possess a behavioral trait (varroa sensitive hygiene) that drives them search out and cannibalize developing bees that have been infected with the young mites. Breeding for this trait is an avenue of research currently being pursued. A large problem in preventing the spread of pests and pathogens is that most bee colonies travel throughout different parts of the US. For example, 60-70% of all commercial bee colonies are relocated to almond orchards every spring, a large majority of which are in California.8 So many bee colonies in one place can lead to disease spread, compounded by the fact that wild bees can also become infected.9 Finally, CCD, a syndrome in which there is a rapid loss of adult worker bees not attributed to parasite or disease, has claimed numerous bee colonies in the past few years. While CCD is still not well understood, the proportion of losses due to the disorder has been reducing each year.
The multiple causes of honey bee decline are addressed in the National Strategy to Promote the Health of Honey Bees and Other Pollinators. This strategy recommends a 34 million dollar budget increase in 2016 from 2015. Pertaining to the honey bee, the plan’s goals are to “Reduce honey bee colony losses during winter to no more than 15% within 10 years” and “Restore or enhance 7 million acres of land for pollinators over the next 5 years through Federal actions and public-private partnerships.” To achieve those goals the task force proposes the following:
- The Pollinator Research Action Plan
- The Pollinator Best Practice Management Guidelines for Federal Building and Designed and Natural Landscapes
- The National Seed Strategy for Rehabilitation and Restoration
- A public outreach and education strategy
Previous strategies to address honeybee decline have been ongoing since 2007 and have seen little success, as made evident by the continued decline of the honeybee population. This National Strategy hopes to achieve what other programs have failed to do by expanding past plans, collaborating between multiple federal agencies and the private sector, and by supporting numerous research initiatives to determine the precise reasons for declining bee numbers by making evidence-based recommendations for how to restore pollinator populations.
By: Sylvina Raver, Ph.D.
Alcohol use disorder, or AUD, is a medical diagnosis given to people who seriously struggle to control their drinking. Approximately 7.2% of American adults suffer from AUD, the consequences of which are hard to overstate. The Centers for Disease Control and Prevention (CDC) estimate that excessive alcohol use contributes to approximately 88,000 deaths per year, and costs the US economy billions of dollars annually in health care costs, criminal justice, automobile accidents, and lost workplace productivity. For those who seek treatment for excessive drinking – either voluntarily or through court-mandated recovery programs – the traditional treatment method has been a faith-based 12-step program, such as Alcoholics Anonymous (AA). For many people, AA is a life-saving experience. But for many others, AUD persists despite determinedly “working the 12 steps” of the program.
A recent article published by The Atlantic calls into question Americans’ reliance on 12-step programs as the primary method to treat AUD. The article’s author claims that compelling data in support of AA’s efficacy are seriously lacking, and that accumulating scientific evidence argues against many tenants of the program. In contrast to AA, which is notoriously difficult to study, many other treatments have been rigorously tested, and now have large bodies of research that support their efficacy. Since its passage in 2010, the Affordable Care Act (ACA) has mandated that health insurance plans and state-run Medicaid programs must cover substance abuse services, which include treatments for AUD, as an “essential health benefit.” However, the law does not specify which treatment programs are the most effective and thus should be covered. As private insurers and government health care programs expand coverage for AUD treatments under the ACA, it’s crucial to consider those methods that have sound experimental support and that are in accordance with what modern neuroscience tells us about disorders of alcohol use and abuse.
The precise mechanisms that underlie AUD, as well as the genetic underpinnings responsible for people’s differential susceptibility to the disease, are the focus of ongoing research, and accumulating evidence indicates an intersection between the brain’s arousal, reward, and stress systems. Early use of alcohol is pleasurable and positively reinforcing, but the drug can take on negative reinforcing qualities during the transition to dependence, as users drink to prevent negative consequences, including withdrawal symptoms. Chronic alcohol abuse leads to adaptations in brain networks and neurotransmitters that control motivation, reward, stress, and arousal. If AUD’s progression is not halted through interventions and appropriate treatments, these alcohol-induced neuroadaptations can worsen over time and contribute to the deadly nature of severe AUD.
Fortunately, treatments for AUD can be extremely effective, although many of them are not well known outside of the medical and addiction communities. The 12 steps outlined by Alcoholics Anonymous have become synonymous with treatment for alcohol abuse in the US, and are deeply entrenched in rehabilitation culture. When it was introduced in the 1930’s, AA was modern in treating alcoholism as a disease, rather than simply as a failure of moral character. However, some of its central tenants are now at odds with our current knowledge of AUD. For example, AA members are instructed to admit that they are “powerless” over alcohol and to completely abstain from drinking. While this approach may be necessary for some individuals, total alcohol abstinence can actually be detrimental to many patients’ recovery process. Basic and clinical neuroscience research has shown that complete abstinence from alcohol can actually increase one’s urge to drink, leading animals and humans to binge once they have access to alcohol again. Furthermore, the type of black-or-white dichotomy inherent to AA – either completely abstinent or not, alcoholic or not – does a disservice to the vast majority of those with AUD who land along a spectrum of problematic alcohol use. The newest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) combines two previously distinct disorders, alcohol abuse and alcohol dependence, into the single, overarching Alcohol Use Disorder (AUD). AUD is further classified as mild, moderate or severe, depending on the number of criteria that a person meets, and treatment programs must be individually adopted for the severity of one’s disorder. Approximately 15% of adults with AUD fall on the severe end of the spectrum and require intensive treatment for their disease. However, the remaining 85% fall in to the mild or moderate categories, and seem to benefit most from brief interventions by medical professionals that help them change unhealthy drinking habits.
Twelve-step programs, such as AA, are not the only options available for AUD treatment, and many approaches are supported by decades of solid research. These treatment practices are collectively called “evidence-based treatments” and can be broadly classified as pharmacotherapies and behavioral therapies. Many experts in addiction medicine believe that pharmacotherapy, or medication-assisted treatment, represents a powerful yet underutilized tool to address moderate and severe AUD. A recent panel convened by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) and the Substance Abuse and Mental Health Services Administration (SAMHSA) issued a report that describes the use of FDA-approved medications in clinical practice for the treatment of AUD. These include:
- Naltrexone (in both oral and extended-release injectable forms), which blocks opioid receptors in the brain to interfere with the rewarding effects of drinking and reduces cravings for alcohol,
- Disulfiram, which interferes with alcohol degradation to produce an unpleasant reaction if a person drinks alcohol,
- Acamprosate, which acts on the GABA and glutamate neurotransmitter systems to help reduce the effects of alcohol withdrawal, including anxiety, insomnia, restlessness, and dysphoria.
The NIAAA/SAMHSA panel concludes, “Medication-assisted treatment shows a lot of promise in reducing alcohol use and promoting abstinence in patients diagnosed with alcohol use disorder.”
Behavioral therapies are also highly effective for addressing AUD, and can be combined with pharmacotherapies or pursued on their own. These approaches help people to modify their attitudes and behaviors about alcohol, become engaged in their treatment, and increase their arsenal of coping skills to better handle stressors and environmental cues that may trigger problem drinking. Evidence-based behavioral therapies for AUD include:
- Cognitive Behavioral Therapy, which recognizes that learning processes play a central role in alcohol addiction and helps patients to enhance their self-control through developing effective coping strategies,
- Contingency Management Interventions/Motivational Incentives, which involve giving patients tangible rewards (often financial) to reinforce positive behaviors, such as reducing their alcohol use, attending counseling sessions, and completing goal-related activities,
- Motivational Enhancement Therapy, which helps patients resolve any ambivalence about engaging in AUD treatment to stop or reduce their alcohol use, and aims to evoke rapid and internally motivated changes, rather than guide the individual stepwise through the recovery process,
- Community Reinforcement Approach Plus Vouchers, a 24-week outpatient therapy that uses a range of recreational, familial, social, and vocational reinforcers, combined with material incentives, to make a non-alcohol or responsible-alcohol-using lifestyle more rewarding than the alternative,
- 12-Step Facilitation Therapy (such as Alcoholics Anonymous), which is an active engagement strategy to promote abstinence with the support of 12-step self-help groups and adherence to the principals of: 1) acceptance of the chronic, progressive nature of the disease; 2) surrender to a higher power/fellowship of the support structure; and 3) active involvement in 12-step meetings and related activities.
Of the estimated 17 million Americans who suffer from AUD, only about 13% receive any type of treatment. The ACA may have the power to drastically improve this situation with its emphasis on primary prevention, so that patients struggling with mild symptoms of AUD can be more easily identified before the disorder progresses. Addiction experts and other health care providers have identified the crucial roles that general and mental healthcare settings – including primary, urgent, and emergency care – can play in early identification of problematic alcohol use, and in providing initial brief interventions for patients. These types of early screening and intervention efforts, combined with evidence-based treatments, can provide hope to the tens of millions of Americans struggling with AUD.