Risk analysis document: One Health considerations associated with importation of bat guano as fertilizer in Canada

Assessment completed: January 9, 2026 (with data as of September 29, 2025)

On this page

• Purpose
• Scope
• Background
• Risk assessment summary
• Future risk in Canada
• Conclusions
• Risk management and communication considerations
• Proposed risk management recommendations and communications
• Acknowledgements
• Endnotes
• References

Purpose

This Risk Analysis Document (RAD) combines risk assessment results with risk management and risk communication considerations and/or recommendations, in order to integrate the three components of risk analysis illustrated in the figure below^{Footnote 1}.

Figure 1: Text description

The figure represents three separate boxes connected by arrows pointing in both directions. The text in the three boxes respectively indicate "risk assessment", "risk management" and "risk communication".

The purpose is to inform long-term policy decisions of the Canadian Food Inspection Agency (CFIA) related to the importation of bat guano, which is currently banned for import into Canada. This topic initially came to the Public Health Agency of Canada (PHAC) in 2020 from the CFIA. The PHAC responses at that time recommended that a risk assessment be conducted. It was determined that this topic would be a good candidate for piloting the new One Health approach to risk assessment (OHARA) Framework.

Scope

The scope of the request is focused on public and animal (primarily wildlife) health considerations associated with the importation of bat guano^{Footnote a}. In particular, the risk framing exercise conducted by the multi-sectoral Steering Committee identified white nose syndrome in bats, zoonotic diseases in humans, and antimicrobial resistance in humans and animals as potential hazards of concern. While livestock animals are also susceptible to some of the hazards, federally reportable/notifiable animal pathogens were excluded from the current document because they have already been the subject of scientific evaluation by the CFIA.

Background

In 2020, a foreign facility requested export of bat guano to Canada, challenging the ban that was established in 2014. The CFIA requested an opinion from PHAC on the public health risks associated with import of bat guano. The PHAC responded to the CFIA, recommending that the ban stay in place and that a full risk assessment be completed. With the development of the OHARA Framework, between 2022 and 2024, it was determined that this topic would be a good candidate for piloting the new approach.

In November 2023, the Risk Assessment Hub (formerly the Centre for Integrated Risk Assessment [CIRA]) convened a multi-sectoral Steering Committee to discuss the issue, frame the risk, and determine if a risk assessment was required. Representatives were present from PHAC, CFIA, Environment and Climate Change Canada (ECCC), and Canada Border Services Agency (CBSA). Previous scientific analyses were shared, including an identification of hazards associated with bat guano (CFIA) and an analysis of import manifests since the implementation of the ban (ECCC)^{Footnote 2Footnote 3}. The conclusion of the Committee was that a risk assessment, focused on specific risk questions, would be beneficial to inform long-term policy decisions.

Since public health was a significant component of the risk questions and PHAC had a One Health risk assessment team, it was agreed by the Committee that PHAC would take the lead on drafting the assessment, with input from a multi-sectoral Technical Team. Due to the presence of the ban, the Committee did not attribute any urgency to the assessment. Therefore, the risk assessment was completed in the context of competing priorities.

Risk assessment summary

During risk framing with the multi-sectoral Steering Committee, three risk questions were chosen for assessment, along with consideration of future risks with high uncertainty.

Question 1: What would be the annual likelihood of at least one bat in Canada being infected by Pseudogymnoascus destructans as a result of imported bat guano if the ban was not in place, and what would be the resulting impacts on bat populations and the ecosystem?

Pseudogymnoascus destructans (Pd) is a fungal pathogen and the causative agent of white-nose syndrome (WNS) in hibernating bats in North America, Europe and Asia. The disease is spreading rapidly across North America, affecting several bat species. In response to the sudden and dramatic declines caused by WNS, three of Canada’s most widespread bat species were emergency listed as Endangered under the Species at Risk Act (SARA) in 2014. WNS activities are delivered under ECCC’s SAR recovery program.

The overall likelihood of at least one bat in Canada being infected by Pd as a result of imported bat guano is moderate to high, with high uncertainty. If Pd spores are present in bat guano products imported into Canada, and they become present in the environment through the use of guano as a fertilizer, this, coupled with the foraging behavior of bats between caves and croplands would facilitate exposure of bats to spores present on the fields. The likelihood depends on type of product, amount of product imported with the ban not in place, the origin (time and space) of the imports, where in Canada the import occurs, the extent of immunity (and other biological and habitat parameters that confer protection) in the exposed bat populations, and the quantity of Pd in the exposure. The uncertainty is high due to knowledge gaps related to processing, lack of information on how much guano is used and how it is used, and limited information on immunity and infectious dose.

The magnitude of effect on affected bats, bat populations, and ecosystems in Canada is estimated to be major to severe, with low uncertainty. While it may be difficult to accurately predict the outcome of WNS in some bat species, evidence shows that WNS has drastically changed the composition of bat communities in Canada. The impact on populations already affected by Pd is more uncertain and could range from even more dramatic mortality (and possible extinction) to an accelerated acquisition of immunity in surviving bats. Once imported, the most likely scenario is that the disease would spread from the original zone in which the guano was used and extend across Canada over the long term. While the pathogen poses no direct risk to human health, the decimation of bat populations will undoubtedly lead to a surge in pest populations, resulting in increased crop damage and higher pesticide use, affecting overall ecosystem resilience, biodiversity and agriculture.

Question 2: What would be the annual likelihood of at least one human in Canada being infected by a zoonotic pathogen as a result of imported bat guano if the ban was not in place, and what would be the resulting impacts on public health?

Eight (8) zoonotic pathogens have been identified as potential hazards for public health associated with imported bat guano.

Two (2) are tick-borne pathogens that have been found in bat guano (Anaplasma phagocytophilum and Rickettsia spp. [mainly R. monacensis]). Both are present in ticks that can be found on bats, and may be found in bat guano if they are carried by bats or a tick feeding on the bat has fallen into the guano. The diseases associated with these pathogens are not widespread in Canada yet, and in most regions human cases are still rare.

The overall likelihood of at least one individual in Canada being infected by these two tick-borne pathogens as a result of imported bat guano is estimated as negligible, with high uncertainty. The expected prevalence of the pathogens in the bat guano is very low and they have a limited ability to survive free in the guano or inside ticks that have fallen into the guano. The high uncertainty is due to limited or no information on the processing and treatment procedures for bat guano in the source countries that would affect ticks and pathogen survival.

Two (2) zoonotic bacteria were assessed as potential hazards: Brucella spp. and Mycobacterium tuberculosis. While humans are the primary host of M. tuberculosis, bats have recently emerged as possible carriers of the pathogen. Tuberculosis occurs in every part of the world, and in Canada is mostly reported in foreign-born individuals and Indigenous Peoples. The overall likelihood of at least one individual in Canada being infected by M. tuberculosis as a result of imported bat guano is estimated as negligible because of the very low expected prevalence of the pathogen in bat guano. The uncertainty is high due to limited or no information on the origin of the bat guano and the pre-border processing. For the tick-borne pathogens and M. tuberculosis assessed above, impact assessment was not performed as likelihood is negligible.

Brucellosis in humans is predominantly caused by four different species, including B. melitensis, which DNA has been found in bats. There is also a new pathogenic species named B. nosferati, which has been reported in bats and possesses all the required virulence characteristics of other zoonotic Brucella species. Human brucellosis is quite rare in Canada. The overall likelihood of at least one agricultural worker or gardener^{Footnote b} in Canada being infected by B. nosferati or B. melitensis as a result of imported bat guano is estimated as very low because of the very low expected prevalence of both B. nosferati and B. melitensis in bat guano. There is a negligible likelihood for anyone other than an agricultural worker or a gardener due to the routes of exposure for Brucella species. The uncertainty is high due to the limited information about the actual presence of a living form of B. melitensis in bat guano (as opposed to B. nosferati), the general bat guano processing in source countries and Canada, the geographic distribution of imported bat guano, and the precise effect of different environmental factors on the survival of the bacteria in bat guano.

The impact on an individual (agricultural worker or gardener) is estimated to be moderate for both Brucella species, with low uncertainty for B. melitensis and high uncertainty for B. nosferati. Since the most likely spread scenario would be no or very limited spread beyond the initial human case, the impact of B. nosferati or B. melitensis to the overall population in Canada is estimated to be minor with low uncertainty. The uncertainty is low because there is a sufficient quantity of information on the spread of brucellosis in humans.

Finally, 4 virus families were assessed: coronaviruses (SAR-CoV-1, MERS-CoV and SARS-CoV-2)^{Footnote c}, filoviruses (Ebola and Marburg viruses), henipaviruses (Nipah and Hendra viruses) and lyssaviruses (Rabies virus). All can be found in bat guano. Human cases of coronaviruses and lyssaviruses can be found in Canada, but there are no cases of henipaviruses or filoviruses.

The overall likelihood of at least one individual in Canada being infected by a coronavirus as a result of imported bat guano is estimated as negligible, mainly due to the survival capacity of these viruses in the environment. The uncertainty is low because there is enough knowledge on coronavirus survival capacity in the environment in relation to the duration of bat guano transportation to Canada.

The overall likelihoods of at least one agricultural worker or gardener in Canada being infected by filoviruses, henipaviruses (Nipah only) and lyssaviruses as a result of imported bat guano are estimated as low to very-low, mainly because of the expected low prevalence and limited survival capacity of the viruses in bat guano. There is a negligible likelihood for anyone other than an agricultural worker or a gardener due to the routes of exposure for these viruses. The uncertainty is high mainly due to missing information on processing before and after arrival in Canada and geographic distribution of bat guano.

Unlike Nipah virus, the overall likelihood of at least one individual in Canada being infected by Hendra virus as a result of imported bat guano is estimated as negligible. This is because Hendra virus is stated to clearly not be transmitted person-to-person or directly from bats to humans (i.e., it necessitates an intermediate host), whereas this is less clear for Nipah virus.

The impact of henipaviruses (Nipah), Filoviruses and Lyssaviruses on an individual (agricultural worker or gardener) in Canada is estimated to be severe because of the high case fatality rates and the limited treatment options, with low uncertainty. The most likely spread scenario would be no or very limited spread beyond the initial human case due to mobilization of containment efforts. The impact on the overall population is moderate for henipaviruses (Nipah) and filoviruses, with low uncertainty, because it is expected that any domestically-acquired case would cause fear and significant resource mobilization. The impact on the overall population is minor for lyssaviruses, with low uncertainty, because rapid detection and treatment will greatly limit the spread of the virus and the impact on the community.

Question 3: What would be the annual likelihood of at least one human or animal in Canada being infected by antimicrobial resistant organisms as a result of imported bat guano if the ban was not in place, and what would be the resulting impacts on public and animal health?

Antimicrobial resistance (AMR) is a serious threat for human health, as well as animal health and welfare. Bats may serve as reservoirs for antibiotic resistance genes and antibiotic-resistant bacteria (including multi-drug resistant bacteria). AMR is considered a potential hazard in the commodity because it has been reported in bats and bat guano, and, although AMR already exists in Canada, it is a major public health concern.

The overall likelihood of at least one individual in Canada being infected by antibioticresistant bacteria as a result of imported bat guano is estimated to be moderate to high for agricultural workers or gardeners and very low for by-standers^{Footnote d}. This difference in overall likelihood is mainly driven by the exposure likelihood, which is higher for agricultural workers or gardeners because of proximity to the bat guano. The uncertainty is high, mainly due to the lack of information about bat guano processing before and after arrival in Canada, the types of bacteria that are carrying AMR genes, the type of AMR, and geographic distribution of imported bat guano.

The impact of bat guano-related AMR to an individual and to the overall population in Canada is estimated to be moderate. The most likely spread scenario would be spread beyond the farm, with spread more widely in Canada in the medium term. The uncertainty around the impact estimate is high at the individual level because it depends largely on the vulnerability status of the individual, and at the population level because of the lack of information on the potential type of bat guano-related AMR of concern, the landscape of the particular AMR hazard in Canada at the time of importation, and its spread characteristics.

Future risk in Canada

In addition to risks associated with bat guano imported into Canada, as assessed by the three risk questions in this report, the collection of bat guano in source countries has the potential to contribute to environmental and pandemic risks globally that may affect Canada in the future. However, these risks are not simple: they are the result of multiple drivers and series of conditions that lead eventually to disastrous results. There is a high level of uncertainty associated with such complex, multi-step future risks resulting in a large range of plausible outcomes.

The drivers of emergence and amplification of pandemics were recently analysed in the Global Preparedness Monitoring Board (GPMB) report The Changing Face of Pandemic Risk. One driver contributing to the spread of animal diseases, potentially leading to pandemic emergence, is trade in animals and animal products, which has significantly increased and changed shape in recent years. Another driver is land-use change: places where the human-animal-environment interface is particularly intricate could stimulate emergence of novel viruses with pandemic potential^{Footnote 4}. The bat cave environment could be an example of such a place, if bat guano is regularly collected. Entering bat caves carries the potential risk of direct contact with infected bats and contamination of shoes and clothing with potentially contaminated bat guano. If infected, people may travel before clinical symptoms develop. There have been reported cases of Marburg virus (filovirus) importation into the Netherlands from ecotourists visiting the Python cave in Uganda^{Footnote 5}.

On the other hand, the GPMB report describes many other drivers of pandemics that would have effects over and above those associated with bat guano trade, such as climate change, intensive agriculture, global movement of humans, urbanization, and misinformation. In context with all of these other potential pandemic drivers, bat guano collection and importation is considered to be a relatively smaller contributor. However, this is associated with high uncertainty.

In addition to pandemic risk, the collection of bat guano for export could be a driver of environmental risks such as reduction in bat populations and resulting loss of insect control, seed dispersal and pollination^{Footnote 6}. Bat populations are very sensitive to disturbance, and cave ecosystems depend on guano as a source of nutrients. Guano collection can involve cave modification, loud noise, bright lights, and changes in air temperature and humidity that disturb the resident bats^{Footnote 7}. There is high uncertainty regarding the role played by bat guano collection in these environmental risks, especially if guidelines to minimize disturbance are followed, and the impact that these environmental risks could have on Canada.

Conclusions

The overall picture of risks is heterogeneous, is often dependent on the activity of the exposed individual (agricultural worker and gardener or not), and translates into three main patterns:

• High likelihood and high impact. This is the case for Pd (for bat populations) and for AMR (for agricultural workers, gardeners and animal health). These hazards are frequently found in bat guano, resistant in the environment, and have serious consequences for individuals and populations;
• Moderate to high impact, but with a low likelihood of occurrence. This is the case for some zoonotic pathogens that cause moderate to severe symptoms for an individual (agricultural worker and gardener) and possible important consequences in the population, but are relatively rare in bat guano and/or have low resistance in the environment (filoviruses, henipaviruses (Nipah only), lyssaviruses, Brucella spp.). There is a negligible likelihood for anyone other than an agricultural worker or gardener due to the routes of exposure for these pathogens. This is also the case for AMR if we consider general population (not agricultural farmer nor gardener);
• Negligible likelihood of occurrence, and no impact. This is the case for A. phagocytophilum, coronaviruses, henipaviruses (Hendra only), M. tuberculosis and Rickettsia spp. that are associated with a very rare prevalence in bat guano, in addition to a poor resistance in the environment.

The uncertainty for the vast majority of the likelihood estimates is high whereas the uncertainty for impact is low. In other words, while the chances of the hazards occurring are highly variable and depend on information that is unavailable, the impact these hazards would have is clearly defined.

In addition to the risks estimated in relation to bat guano importation into Canada, the collection of bat guano in source countries may contribute to broader risks that could ultimately affect Canada. While the scale of this contribution is difficult to quantify, the consequences of such potential risks are significant.

Risk management and communication considerations

In addition to the conclusions of risk assessments, a number of other considerations are incorporated into decisions regarding risk management and communication, including:

• The risks identified above would primarily affect wildlife and public health (i.e., white nose syndrome, antimicrobial resistance, and to some extent, zoonotic pathogens and potential for environmental and/or pandemic hazards). These risks are not focused on domestic animal health and generally are not federally reportable/notifiable animal pathogens; yet the responsibility for regulating the importation of bat guano lies with the CFIA.
• It is challenging to strictly enforce a ban. Products associated with bat guano were previously found to have entered Canada after the implementation of the ban. It is possible that this may occur again.
• It is challenging to monitor imports of wildlife and wildlife products, such as guano. A study of the importation of dogs by PHAC and CBSA illustrates the problems and the need for improved tracking capabilities^{Footnote 8}. The consequences of continuing with current systems and processes include a lack of ability to intercept illegal imports of bat guano or monitor the trade in guano and other fertilizer products for risk assessment and risk management purposes. Risk cannot be managed without accurate and complete trade data on the commodities imported into and exported from Canada.
• While some counter-measures may exist to prevent exposure of humans to zoonotic pathogens (e.g., personal protective equipment), few protection measures exist for prevention of exposure of wildlife.
• Consider whether continued entry of bat guano, despite a ban, reflects a low perception of risk, limited awareness or misunderstanding and if so, what communications activities could be taken to address these gaps.

Proposed risk management recommendations and communications

Recommendations are provided to address the specific findings of the risk assessment, considering the other risk management and communication considerations highlighted above, while identifying those that would support a strategic approach to issues concerning bat guano importation. These are for consideration by implicated government and non-government parties according to their mandate, authorities, roles and responsibilities, policies, resources and priorities.

Regulation

• Maintain the ban on the importation of bat guano.

Considerations include:

• risks to human and animal health identified above;
• high uncertainty even where some likelihoods were assessed to be low;
• high potential magnitude of impacts; and,
• difficulties associated with preventing and controlling disease in wildlife.

Coordination and collaboration

• Continue to maintain cross-sectoral One Health collaborations (including wildlife, agricultural, and public health departments/agencies at federal, provincial, territorial and Indigenous organizations, and others [e.g., academia, industry]) as required.

Risk communication

• Develop targeted, evidence-based and transparent risk communications to address the continued importation of bat guano despite the ban and the importance of maintaining the ban for both human and animal health.
  • Messaging should clearly explain the risk to human and animal health (including what is known and uncertain) and reinforce compliance expectations.
  • Communications should be tailored to target audiences, including importers, distributors/retailers and end users clearly outlining the actions required of each group.
  • Messaging should be aligned across federal, provincial/territorial and enforcement bodies to avoid confusion.
• Encourage producers to follow international guidance^{Footnote e} and best practice in bat guano extraction.

Addressing knowledge gaps and uncertainties

Consider supporting research activities to address the knowledge gaps identified in the risk assessment. This will provide additional evidence to inform decision making related to human and/or animal health.

Acknowledgements

Completed by: Public Health Agency of Canada, in collaboration with partners from Environment and Climate Change Canada (ECCC), Canadian Food Inspection Agency (CFIA), Canada Border Services Agency (CBSA) and McMaster University.