Don’t Panic about Hantavirus. Learn To Manage Rodents.

Since 1993, people in the Four Corners area of the U.S. Southwest have faced periodic outbreaks of hantavirus. Although the virus is found elsewhere, the ecology of the rural Southwest—including geography, climate, housing patterns, and close human contact with deer mice—produces ideal conditions for the disease to flourish. Understanding this ecology can help prevent hantavirus outbreaks in humans, as well as other rodent-borne diseases.

>> Tell your local officials to use good sanitation and management to prevent rodent problems.

Much of the rural American Southwest offers ideal habitat for deer mice (Peromyscus maniculatus), who do well in semi-arid environments, grasslands, woodpiles, sheds, cabins, and outbuildings, and carry the virus without becoming sick themselves. Weather patterns of abundant moisture following drought lead to increased rodent activity. Climate change may also affect risk. The American Southwest has experienced sharper shifts between drought and heavy rainfall. These conditions may periodically boost rodent populations. Wildfires and habitat disturbance may also affect how rodents interact with human communities.

The Andes strain of hantavirus, which infected people on the cruise ship MV Hondius, is also carried by rural mice in Argentina and Chile. People typically become infected by inhaling viral particles from these rodents' urine, feces, or saliva. [For this piece, the term rodent is used to refer to mice and rats.] This may occur, for instance, while cleaning a remote cabin infested with wild rodents. This pattern leads to ways to avoid infection. Vacuuming or sweeping up areas that may have been contaminated by live or dead rodents is discouraged because the activity releases viral particles into the air.

Instead, while cleaning:

Wear gloves.
Spray the contaminated area with the disinfectant or bleach solution until very wet, and let it soak for at least 5 minutes.
Use paper towels, a sponge, or a mop to clean up the contaminated area.
Wear an N95 mask to provide another level of protection.

While deer mice may be mostly a rural problem, other rodents—including rats and house mice—affect urban dwellers. Rats and mice contribute to approximately 55 different diseases, including a diverse range of pathogens from viruses to parasitic worms. Unfortunately, facility managers often choose to deal with rodent infestations by primarily setting out poison (rodenticide) baits. Rodenticides are hazardous and pose a very dangerous threat to children and animals, making them either very sick or causing death if ingested. A significant number of peer-reviewed studies document the toxic nature of rodenticides. Second-generation anticoagulant rodenticides (SGARs) have been found in the tissue of various aquatic and terrestrial organisms, leading researchers and conservationists to increasingly scrutinize the role of toxic pesticide drift from bait stations to streams, forests, and other habitats.

An ecological approach to urban rat management, begins by considering the reasons that rats are in an area in the first place. Such an approach would focus on improving the quality of life in low-income areas of degraded housing and other public amenities. Thus, an ecological approach to urban rodent management involves solving social problems as well as scientific problems. It also requires accepting that mice and rat problems can be a symptom of another problem.  Rodents in structures are symptoms of other problems because they are always a factor of “upstream determinants” like weak building codes, disrepair resulting in entry points, or inadequate landscaping practices. Municipal rodent problems are also always unique, with different outbreak sources, conditions, and goals, making clear best practices for rat management a function of conditions on the site.

A review outlines a new paradigm in rodent management. It begins with mapping out the rat problem in the region, “to highlight, for example, where rats are considered problematic, who is vulnerable, who is resilient, what policies are in place to address them and do they work better in some areas, and which municipal departments and sectors of the urban environment are affected.” This new approach emphasizes the improvement of overall community health, rather than focusing on rodents as symptoms of a problem that occurs in a vacuum. In doing so, a community may be able to successfully use different intervening actions—such as proper waste disposal, keeping livestock out of water bodies, and alterations to butchering practices.

>> Tell your local officials to use good sanitation and management to prevent rodent problems. In the event that your local mayor is not in the system, we invite you to email this message to them personally.

The targets for this Action are U.S. Mayors and executive leadership, county and municipal.

Thank you for your active participation! The Action is a multi-step process, so please click submit below to proceed to step two, where you will be able to personalize comments before final submission. The comment maximum limit is 4,000 characters, so it may be necessary to delete some of our prepared message text if editing.

Letter to U.S. Mayors:

Recent news concerning the hantavirus highlights the importance of addressing rodent problems with a socio-ecological approach.

Since 1993, people in the Four Corners area of the U.S. Southwest have faced periodic outbreaks of hantavirus. Although the virus is found elsewhere, the ecology of the rural Southwest—including geography, climate, housing patterns, and close human contact with deer mice—produces ideal conditions for the disease to flourish. Understanding this ecology can help prevent hantavirus in humans, as well as other rodent-borne diseases. The problem raises issues of rodent management in our community and ensuring that we adopt practices that offer control, but do not harm human health and the environment.

Hantavirus is mostly carried by wild rodents—unlike the Andes strain infecting people on the cruise ship MV Hondius. People typically become infected by inhaling viral particles from these rodents’ urine, feces, or saliva—for instance, while cleaning a remote cabin infested with wild rodents. Vacuuming or sweeping up areas that may have been contaminated by live or dead rodents is discouraged because the activity releases viral particles into the air.

Instead, community education is needed to ensure that basic protective practices are followed, such as:

*Wear gloves.

*Spray the contaminated area with the disinfectant or bleach solution until very wet, and let it soak for at least 5 minutes.

*Use paper towels, a sponge, or a mop to clean up the contaminated area.

*Wear an N95 mask to provide another level of protection.

While deer mice may be mostly a rural problem, other rodents—including rats and house mice—affect urban dwellers. Rats and mice contribute to approximately 55 different diseases, including a diverse range of pathogens from viruses to parasitic worms. Unfortunately, facility managers often set out poison (rodenticide) baits. Rodenticides are hazardous and pose a dangerous threat to children and animals, possibly resulting in illness or death. A significant number of peer-reviewed studies document the toxic nature of rodenticides. Second-generation anticoagulant rodenticides (SGARs) have been found in various aquatic and terrestrial organisms, leading researchers and conservationists to increasingly scrutinize the role of toxic pesticide drift from bait stations to streams, forests, and other habitats

An ecological approach to urban rat management begins by considering the reasons that rodents are in an area in the first place. Such an approach would focus on improving the quality of life in low-income areas of degraded housing and other public amenities—thus addressing social problems as well as scientific problems and accepting that rat problems can be a symptom of another problem, such as weak building codes or inadequate landscaping practices. This approach begins by mapping out the rat problem in the region, to highlight where rats are considered problematic, who is vulnerable, who is resilient, what policies are in place to address them, and with what success. Affected municipal departments and sectors of the urban environment need to be identified. This approach emphasizes the improvement of overall community health, rather than focusing on rodents as a problem that occurs in a vacuum. In doing so, a community may be able to successfully use different intervening actions—such as improved building codes, making needed repairs that seal entry points, and proper waste disposal and sanitation practices—to prevent rodent problems

I urge you to adopt an ecological approach to preventing rodent problems.

Thank you.