Hantavirus Pulmonary Syndrome (HPS)
Hantavirus pulmonary syndrome (HPS) is a disease transmitted by infected rodents through urine, feces, or saliva. Humans can contract the disease when they breathe in aerosolized virus. HPS was first recognized in 1993 and has since been identified throughout most of the United States. Although rare, HPS is potentially deadly. Rodent control in and around structures remains the primary strategy for preventing hantavirus infection.
All hantaviruses known to cause HPS are carried by the New World rats and mice. These wild rodents are not generally associated with urban environments, but some (i.e., deer and white-footed mouse) will enter structures in rural and suburban areas.
Several hantaviruses that are pathogenic for humans have been found within United States. Generally, each virus has a single primary rodent host. The deer mouse (Peromyscus maniculatus) is the host for Sin Nombre virus (SNV), the primary causative agent of HPS in the United States. The deer mouse is common and widespread throughout most of the United States. On average approximately 10% of deer mice tested throughout the United States show evidence of infection with SNV.
Other host species include the white-footed mouse (Peromyscus leucopus), the cotton rat (Sigmodon hispidus), and the rice rat (Oryzomys palustris), of which only the white-footed mouse is found in South Dakota. Other sigmodontine rodent species are associated with additional hantaviruses (i.e., woodrats, harvest mouse), but have not yet been implicated in human disease.
It is recommended that you avoid contact with all wild and commensal mice and rats encountered throughout the United States, and also the saliva, urine, and feces from those rodents.
Hantaviruses are surrounded by a lipid or fat envelope, so they are fairly fragile. The envelope can be destroyed and the virus killed by fat solvents, such as ordinary disinfectants and household bleach. One of the most important ways to prevent transmitting the disease is to carefully wet down dead rodents and areas where rodents have been with disinfectant and/or bleach. By doing this, the virus can be killed, thus reducing the chance that the virus will get into the air. The following are steps to be taken when cleaning areas of infestation:
- During cleaning, wear rubber, latex, vinyl, or nitrile gloves.
- Spray dead rodents, rodent urine and droppings with a chlorine solution or disinfectant until thoroughly soaked.
- Use a paper towel to absorb urine and pick up dead rodents, traps, or droppings and place them in a plastic bag.
- When cleanup is complete (or when bag is full), seal the bag, place it into a second plastic bag, and seal the second bag. Dispose of the material in a covered trash can that is regularly emptied.
- After the droppings and urine have been removed, disinfect items that might have been contaminated.
- Disinfect floors (including dirt), countertops, cabinets, drawers, and other durable surfaces with a disinfectant or chlorine solution.
- Steam-clean or shampoo rugs and upholstered furniture.
- Launder bedding and clothing in hot water and detergent. Dry laundry on high heat or hang to dry in the sun. Use protective gloves.
- Books, papers, and other items that cannot be cleaned or thrown away should be left in the sunlight for several hours, or in an area free of rodents for approximately 1 week before cleanup (time renders virus non-infectious).
Before removing gloves, wash gloved hands in a disinfectant or chlorine solution and then wash bare hands in soap and water.
Integrated Pest Management, 2006
During fiscal year 2006, Wind Cave National Park’s Integrated Pest Management (IPM) activities resulted in treatment of 319 acres of exotic plant species. In addition, the Northern Great Plains Exotic Plant Management Team treated 17 acres at the park. Control methods implemented included manual, mechanical, biological and chemical control methods.
The majority of IPM control actions were directed at leafy spurge, Canada thistle, musk thistle, scotch thistle, bull thistle, spotted knapweed, common mullein, common burdock, houndstongue, pennycress, dalmation toadflax, yellow toadflax (butter and eggs), curly dock, St. Johnswort, horehound and western salsify. Survey and mapping activities focused on horehound infestations.
Manual and mechanical control activities in previous years resulted in Canada thistle and St. Johnswort infestations which were noticeably smaller in 2006. Several spotted knapweed locations appear to have been eradicated.
Unfortunately, the number of dalmation toadflax locations increased, possibly due to the many infestations of this species located within 10-15 miles of the park boundary.
Horehound, a drought and disturbance tolerant species, increased dramatically in recent years. The park hopes to control it through prescribed burns, as both the plants and seeds of this species are sensitive to fire.
IPM of exotic plant species continues to be a challenge nationwide. An integrated approach to management can control infestations of non-native plants, while at the same time ensure conservation and protection of native plant and native vegetation community diversity. - Marie Curtin
Comments and feedback about Resource Ramblings are encouraged. Send and should be directed to Dan Foster, in person, or via email.