Tag Archives: spread

July 5, 2023

Hop Latent Viroid (HLVd) & Pathogen Diagnostics: A Comprehensive Overview

By Tassa Saldi, Ph.D.

Hop latent viroid (HLVd) has gained attention as the molecular cause of “dudding disease” and is causing significant economic losses in the cannabis industry.^1,2 Estimates indicate that upwards of 4 billion dollars of market value are lost each year to this pathogen alone.³ The impact of HLVd on cannabis plants necessitates the development and implementation of effective pathogen diagnostics to mitigate its spread and minimize crop damage. With collaborative research efforts, we can gain valuable insights into the characteristics, spread, symptoms and preventive measures associated with HLVd in the cannabis industry.

Viroids: A Brief Overview

Viroids are unique infectious agents composed solely of genetic material, distinct from viruses. Unlike viruses, viroids lack a protective protein layer and solely rely on the host plant for replication and spread. Their stability and ability to persist in various environments make viroids a formidable threat to plant health.

Hop Latent Viroid: Origin and Global Spread

Hop latent viroid was initially identified in hop plants in 1988⁴ and was found to be largely asymptomatic in this crop. Consequently, HLVd has spread worldwide, mostly unchecked by the hops industry. This pathogen has been identified on most continents and in some fields more than 90% of hops plants are infected.⁵ Hop latent viroid very likely jumped from hops into cannabis, due to similar genetics. The timing and mechanism of cross-species transmission to cannabis remains unknown, but the prevalence of HLVd suggests this viroid has been circulating within cannabis for an extended period. Data collected at TUMI Genomics indicates that HLVd is present in all states in the United States where cannabis is legal as well internationally including; Canada, the United Kingdom, France, the Netherlands, Thailand, Austria and Switzerland.

Symptoms and Impacts on Cannabis Plants

HLVd exhibits a wide range of symptoms, which can vary from severe to subtle, affecting the growth, leaf development, flower quality and overall vitality of cannabis plants. Understanding these symptoms is crucial for timely diagnosis and appropriate disease management strategies. However, HLVd can also present asymptomatically, especially in vegetative plants. The only way to determine if your plants are infected is by routine molecular testing.

Modes of Transmission

Mechanical Transmission: HLVd primarily spreads mechanically through contact with infected sap during activities like trimming and handling. Additionally, transmission through contaminated water and the potential role of insects, fungal pathogens and seeds in spreading HLVd have also been observed.

Seed Transmission: Although no published studies exist in cannabis describing the frequency of seed transmission, HLVd does transmit through seeds in hop plants at a rate of around 8%.⁷ Preliminary studies performed by TUMI Genomics in collaboration with EZ-genetics suggest cannabis seed transmission does occur at variable rates depending on strain and level of infection of the parent plants.

Water Transmission: It has also been observed that viroids are in high concentration in the roots⁸ and can move from the root into runoff water.⁹ Plants sharing a common water source with infected plants, such as recirculating water systems or flood and drain procedures, are at risk for transmission of the viroid.

Insect and Other Vector Transmission: The jury is still out as to whether or not insects can transmit HLVd. However, multiple viroids are transmitted via insects, so it is likely that HLVd insect transmission occurs. Recent studies also indicate that fungal pathogens, like Fusarium, can transmit viroid infections.⁶ While pathogenic fungus is a major concern for cannabis growers in its own right, limiting the prevalence and spread of fungal pathogens in your facility could help limit hop latent viroid transmission as well.

Therefore, implementing proper sanitation practices and limiting pest access can help minimize transmission risks.

Preventive Measures

Prevention plays a vital role in safeguarding cannabis crops against HLVd. The STOP program, developed by TUMI Genomics, offers a comprehensive approach that includes maintaining a Sterile environment, Testing mother plants regularly, Organizing the facility to minimize pathogen spread, and Protecting the facility’s borders from introduction of infected plant material, insects and contaminated water. More details on these preventative measures can be found here.

Pathogen Diagnostics

Protecting your plants from hop latent viroid requires accurate identification and removal of infected plants before the infection spreads to other plants. To accomplish this, several critical factors should be considered:

Type of test: HLVd and all viroids can only be detected by a molecular test (a test that detects the presence of DNA/RNA). Among common molecular tests, PCR is generally the most sensitive and accurate method. PCR can provide both a diagnosis and an approximate viroid level, allowing informed management decisions. Other types of molecular tests, such as LAMP and RPA, can formally be as sensitive as PCR, but the classic versions of these assays often suffer from false positive/negative results, reducing accuracy.

Tissue type: An important consideration for HLVd detection is the plant tissue selected for testing, especially when identifying low-level or early infections when HLVd is not yet systemic. Studies completed by TUMI Genomics and others show root tissue contains the highest levels of HLVd and is the most reliable tissue for detection of viroid infection. While upper root tissue appears to contain the highest levels of viroid, roots from anywhere in the root ball are predictive of infection. Samples taken from the leaves/foliage tend to have lower levels of viroid and may produce false negative results.

Testing frequency: Routine pathogen testing is standard practice in general agriculture and is critical to maintain a healthy cannabis crop. Testing of mother plants every 4-6 weeks for economically critical pathogens (such as HLVd) will help ensure a successful run and a high-quality product.

Disinfection Methods

Studies have shown that viroids can remain infectious for longer than 24 hours on most common surfaces¹¹ and 7 weeks in water.¹⁰ Making effective disinfection methods essential to limit the spread of HLVd. While common disinfectants like alcohol and hydrogen peroxide are ineffective against viroids, a 10% bleach solution has shown efficacy in destroying HLVd. Proper tool sterilization practices, such as soaking tools in bleach for 60 seconds, are crucial to prevent transmission during plant handling.

Hop latent viroid poses a significant threat to the cannabis industry, leading to substantial economic losses. Timely and accurate pathogen diagnostics, along with stringent preventive measures, are essential for minimizing the impact of HLVd. Regular testing, proper disinfection protocols and adherence to pathogen prevention programs can help ensure the health and vitality of cannabis crops in the face of this global pandemic.

References

Bektas, A., et al. “Occurrence of Hop Latent Viroid in Cannabis Sativa with Symptoms of Cannabis Stunting Disease in California.” APS Journals, 21 Aug. 2019, doi.org/10.1094/PDIS-03-19-0459-PDN.
Warren, J.G., et al. “Occurrence of Hop Latent Viroid Causing Disease in Cannabis Sativa in California.” APS Journals, 21 Aug. 2019, doi.org/10.1094/PDIS-03-19-0530-PDN.
Cooper, Benjie. “Hop Latent Viroid Causes $4 Billion Cannabis Industry Loss – Candid Chronicle.” Candid Chronicle – Truthful, Straightforward, Blunt Cannabis News, 16 Aug. 2021, candidchronicle.com/hop-latent-viroid-causes-4-billion-cannabis-industry-loss/.
Puchta H, Ramm K, Sänger HL. The molecular structure of hop latent viroid (HLV), a new viroid occurring worldwide in hops. Nucleic Acids Res. 1988 May 25;16(10):4197-216. doi: 10.1093/nar/16.10.4197. PMID: 2454454; PMCID: PMC336624.
Faggioli, Franceso, et al. “Geographical Distribution of Viroids in Europe.” Viroids and Satellites, 31 July 2017, www.sciencedirect.com/science/article/abs/pii/B9780128014981000449#bib47.
Wei S, Bian R, Andika IB, Niu E, Liu Q, Kondo H, Yang L, Zhou H, Pang T, Lian Z, Liu X, Wu Y, Sun L. Symptomatic plant viroid infections in phytopathogenic fungi. Proc Natl Acad Sci U S A. 2019 Jun 25;116(26):13042-13050. doi: 10.1073/pnas.1900762116. Epub 2019 Jun 10. PMID: 31182602; PMCID: PMC6600922.
Singh RP. The discovery and eradication of potato spindle tuber viroid in Canada. Virus disease. 2014 Dec;25(4):415-24. doi: 10.1007/s13337-014-0225-9. Epub 2014 Dec 2. PMID: 25674616; PMCID: PMC4262315.
Jama, Aisha, et al. TUMI Genomics, Fort Collins, CO, 2022, Hop Latent Viroid Levels and Distribution in Cannabis Plant Tissue.
Mackie AE, Coutts BA, Barbetti MJ, Rodoni BC, McKirdy SJ, Jones RAC. Potato spindle tuber viroid: Stability on Common Surfaces and Inactivation With Disinfectants. Plant Dis. 2015 Jun;99(6):770-775. doi: 10.1094/PDIS-09-14-0929-RE. Epub 2015 May 15. PMID: 30699527.
Mackie AE, Coutts BA, Barbetti MJ, Rodoni BC, McKirdy SJ, Jones RAC. Potato spindle tuber viroid: Stability on Common Surfaces and Inactivation With Disinfectants. Plant Dis. 2015 Jun;99(6):770-775. doi: 10.1094/PDIS-09-14-0929-RE. Epub 2015 May 15. PMID: 30699527.
Mackie AE, Coutts BA, Barbetti MJ, Rodoni BC, McKirdy SJ, Jones RAC. Potato spindle tuber viroid: Stability on Common Surfaces and Inactivation With Disinfectants. Plant Dis. 2015 Jun;99(6):770-775. doi: 10.1094/PDIS-09-14-0929-RE. Epub 2015 May 15. PMID: 30699527.

September 15, 2020

California Employment Laws, COVID-19 & Cannabis: How New Regulations Impact Cannabis Businesses

By Conor Dale

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As employers in the cannabis industry adapt to making their businesses run and thrive in the age of COVID-19, federal, state and local jurisdictions have issued new laws and regulations providing rules and guidance on returning employees to work. Employers in the industry should be aware of, and prepare for, these rules moving forward.

Federal guidance regarding COVID testing and employees’ return to the workplace:

Since March, the Equal Employment Opportunity Commission (EEOC) has issued guidance and frequently asked questions (FAQ) concerning employment-related COVID-19 topics. In its September update, the EEOC answered practical questions relating to COVID testing, questions to employees regarding COVID, and employee medical information.

Employee testing

The EEOC has already stated that employers may administer COVID-19 tests before initially permitting employees to enter the workplace. In its September FAQs, the EEOC confirms that employers may conduct periodic tests to ensure that employees are COVID free and do not pose a threat to coworkers and customers. The EEOC also clarified that employers administering regular COVID-19 tests is consistent with current Centers for Disease Control and Prevention (CDC) guidance and that following recommendations by the CDC or other public health authorities such as the Food and Drug Administration (FDA) regarding employee testing and screening is appropriate. The EEOC acknowledges that the CDC and FDA may revise their recommendations based on new information, and reminds employers to keep apprised of these updates.

COVID questions for employees

The EEOC also confirmed that employers may ask employees returning to the workplace if they have been tested for COVID-19, which, presumably, permits employers to ask if the employee’s test was positive or negative. Please note that an employer’s right to ask employees about COVID testing is based on the potential threat that infected employees could pose to others if they physically return to work. As a result, the EEOC clarified that asking employees who exclusively work remotely and/or do not physically interact with other employees or customers about potential COVID-19 status would not be appropriate. The EEOC also stated that an employer may not directly ask whether an employee’s family members have COVID-19 or symptoms associated with COVID-19. This is because the Genetic Information Nondiscrimination Act (GINA) generally prohibits employers from asking employees medical questions about family members. However, the EEOC clarified employers may ask employees if they have had contact with anyone diagnosed with COVID-19 or who may have symptoms associated with the disease.

Sharing information about employees with COVID

The Americans with Disabilities Act (ADA) requires employers to confidentially maintain information regarding employees’ medical condition. The EEOC’s updated FAQS clarify that managers who learn that an employee has COVID may report this information to appropriate individuals within their organization in order to comply with public health guidance, such as relaying this information to government contact tracing programs. Employers should consider directing managers on how, and to whom, to make such reports, and specifically instruct employees who have a need to know about the COVID status of their coworkers to maintain the confidentiality of that information. The EEOC also clarified that workers may report to managers about the COVID status of a coworker in the same workplace.

California state guidance on employees returning to work

The state of California also recently released a “COVID-19 Employer Playbook” which provides guidance on employees to return to work. That playbook states that employees with COVID related symptoms may return to work 24 hours after their last fever, without the use of fever-reducing medications, if there had been an improvement in symptoms and at least 10 days had passed since symptoms first appeared. This was also indicated in the California Department of Public Health (CDPH) Order, issued in June, about responding to COVID-19 in the Workplace.

More recently, on August 24^th, the CDPH released similar guidance which reiterates when employees who have tested positive for COVID could return to the workplace when: (1) at least 10 days have passed since symptoms first appeared; (2) at least 24 hours have passed with no fever (without the use of fever-reducing medications), and (3) their other symptoms have improved. Conversely, individuals who test positive for COVID and who never develop symptoms may return to work or school 10 days after the date of their first positive test.

Employers should also check local public health orders for their county when determining how and when to return an employee who has recovered from COVID-19. It is important to also confer with your employment counsel when implementing new policies and procedures related to COVID-19, particularly given that the guidance issued by government authorities continues to evolve at a rapid pace.

Return to work laws on the horizon

Finally, a number of local governments in California such as the City of San Francisco, Oakland and Los Angeles have enacted return-to-work ordinances generally requiring employers to offer available positions to former employees who have been separated from employment due to coronavirus related business slowdowns or government-issued shutdown orders. The California legislature is also in the process of enacting a potential law that would similarly require employers in the state to offer vacant job positions to former employees whose employment ended due to COVID.

While the San Francisco ordinance only addresses positions in San Francisco and the Oakland and Los Angeles ordinances primarily address large employers in the hospitality and restaurant industries, cannabis industry employers should strongly consider offering vacant job positions to former employees whose employment ended due to COVID in order to comply with these ordinances and other potentially applicable future laws and in an effort to avoid potential legal claims from former employees.

Employers are strongly advised to consult with counsel to make sure they are following the requirements of these new laws and regulations.

March 15, 2020

Coronavirus Guidelines for the Cannabis Industry

By Aaron Green

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The World Health Organization (WHO) recently recognized COVID-19, the disease caused by the coronavirus SARS-CoV-2, a pandemic. What can cannabis businesses do to help reduce transmission?

At the time of this writing, community transmission of COVID-19 has been observed in every continent except Antarctica. While China and South Korea are showing signs of containment, with negative disease growth rates, the rest of world is experiencing positive – and in some cases exponential – disease growth rates. Many companies in the cannabis industry are asking: what can we do to slow the spread of the virus and get ahead of the outbreak?

By adopting sensible policies, businesses play a key role in reducing disease transmission. On March 13, 2020, The International Chamber of Commerce (ICC), in collaboration with the WHO and New England Complex Systems Institute (NECSI), released Coronavirus Guidelines for Business, a summary of actions businesses can take to reduce immediate risks to employees and long-term risks to costs and profitability. The guidelines have since been delivered to more than 45 million businesses worldwide.

There are four sections to the guidelines:

General Recommendations
Meetings, Travel and Visitors
Workplaces
Retail and Hospitality

Specific recommendations relevant to the cannabis industry include working remotely where possible, avoiding unnecessary travel and keeping clear records of each day’s contacts. Where possible, a pick-up and drop-off service, home delivery or drive by services are recommended.

Businesses should be developing, readying and implementing business continuity plans based on the ICC guidelines. At this point, a conservative position would be to assume that if an outbreak has not been reported locally it is only a matter of time before local cases are reported. Specific actions businesses should take will depend on location, nature of the workplace and potential disruptiveness to operations.

The ICC and NECSI Coronavirus Guidelines for Business can be found here.

endCoronavirus.org is built and maintained by NECSI and its collaborators and specializes in networks, agent-based modeling, multi-scale analysis and complexity as it relates to COVID-19.

The International Chamber of Commerce (ICC) is the institutional representative of more than 45 million companies in over 100 countries. ICC’s core mission is to make business work for everyone, every day, everywhere. Through a unique mix of advocacy, solutions and standard setting, they promote international trade, responsible business conduct and a global outreach to regulation, in addition to providing market-leading dispute resolution services. Their members include many of the world’s leading companies, SMEs, business associations and local chambers of commerce.

The New England Complex Systems Institute (NECSI) is an independent academic research and educational institution with students, postdoctoral fellows and faculty. In addition to the in-house research team, NECSI has co-faculty, students and affiliates from MIT, Harvard, Brandeis and other universities nationally and internationally.