The hantavirus: will it come to camp?

Only a few people have questioned whether the hantavirus will come to camp. Most haven't considered it a threat. Yet the virus is not confined to the cases which made summer headlines and originated in the Southwest. A case was identified in North Dakota this past September.

A healthy concern seems appropriate. Hantavirus questions may appear next summer as frequently as those surrounding Lyme disease and killer bees. What is the camp doing to protect people?

According to epidemiologists in both Minnesota and North Dakota, there is no evidence that the virus will be a major threat, simply because most rodent populations, which are the primary reservoir hosts of recognized hantaviruses, are not infected (personal communication). Recommended action is that camp nurses contact the state health department for the state in which their camp is located and inquire about the incidence and prevalence of hantavirus infection. It is predicted that no cases will he known. In this scenario, there is minimal risk to the camp.

Understand that the hantavirus infects humans when an individual comes in contact with the saliva, urine or feces of a contaminated rodent. This contact is commonly through an airborne transmission. According to the Centers for Disease Control (1993), the virus remains viable in dried excreta and is transmitted when a person disturbs the excreta by sweeping or wiping ("cleaning up"). Transmission may also occur when contaminated excreta contacts broken skin, is introduced onto the conjunctivae, or, possibly, ingested in contaminated food or water. People bitten by infected rodents have also been infected.

The CDC recommends that actions be taken which minimize or eliminate rodents from an area. This preventative approach seeks to keep distance between humans and mice, a carrier commonly in contact with people. In general, the goal is to reduce the availability of rodent food sources and nesting sites. Recommended actions include keeping woodpiles 100 feet or more from living areas, cutting brush and grass within the same distance, ensuring continuous use of spring-loaded rodent traps, and keeping food and water (including pet food and garbage containers) tightly closed. Some of these actions are already used by camps to not only control rodent population but also manage exposure to illnesses such as Lyme disease.

The camp staff often cleans camp as part of orientation. Since most camp facilities are used seasonally, sweeping out the winter's accumulation of mice nests and chipmunk food caches is common -- and so is a considerable amount of dust. If hantavirus infection is present, it is probably this group which is most at risk.

Consider that hantavirus may not be the only contaminant. It is good practice to contact the state' s epiderniologist, determine what illnesses are transmitted in the geographic area via exposure to rodents, bats and whatever else lives nearby, and then adapt cleaning procedures to minimize or eliminate the risk. In most cases it will he as simple as wearing a mask during early season cleaning, wetmopping with a simple bleach solution instead of sweeping (three tablespoons per gallon of water is recommended by the CDC), and showering/changing clothes after completing the task.

Should your state epidemiologist report hantavirus infection, take the information seriously. The CDC has published precautions for workers in affected areas who are exposed to rodents. The precautions include use of high-efficiency respirators, boots, and goggles when cleaning habitats with known hantavirus infection. If infection is reported in your camp's area, it may be possible for the state's health department to test rodent excreta from a cabin in early spring. This may be a viable option but only when infection has been reported. Remember: not all rodents are carriers.

Also consider your camp's hiking and tripping program. The CDC states: "There is no evidence to suggests that travel into the affected areas should be restricted...however, persons engaged in outdoor activities such as camping or hiking should take precautions to reduce the likelihood of their exposure to potentially infectious materials." Recommended guidelines include using camping or other enclosed shelters that are rodent infested only after they have been cleaned and disinfected, pitching tents or placing sleeping bags away from areas in proximity to rodent feces and/or burrows, and using tents with floors or raising the sleeping bag at least twelve inches above the ground.

Camps will continue to program using the natural environment. As a result, camp health management must sensitively monitor concerns of that environment and develop an ability to keep concern appropriate to the situation. Establish a relationship with the state epidemiologist; contact this person in early spring and act on the given recommendations. Assume a position of prevention. Work now to prevent what may occur if one does not intervene.

Centers for Disease Control, U.S. Department of Health and Hman SeNices. (1993). Hantavirus infection -- Southwestern United States: Interim recommendations for risk reduction. MMWR: Morbidity and Mortality Weekly Report, 42(No. RR-11), 1-12,

Reducing the Risk of Hnatavirus Infection

* Avoid coming into contact with rodentsand rodent burrowsot disturbing dens (such as pack rat nests).

* Do not use cabins or other enclosed shelters that are rodent infested until they have been appropriately cleaned and disinfected.

* Do not pitch tents or place sleeping bags in areas in proximity to rodent feces or burrows or near possible rodent shelters (e.g. garbage dumps or woodpiles).

* If possible, do not sleep on the bare ground. Use a cot with the sleeping surface at least 12 inches abouve the ground. Use tents with floors.

* Keep food in rodent-proof containers.

* Promptly bury (or-preferably-burn followed by burying, when in accordance with local requirements) all garbage and trash, or discard in covered trash containers.

* Use only bottled water or water that has been disinfected by filtration, boiling, chlorination, or iodination for drinking, cooking, washing dishes, and brushes teeth.

--Centers for Disease Control, U.S. Department

of Health and Human Services, (1993).