Fight the Bite!

Hantavirus. Plague. West Nile virus. Whether you live high in the mountains or down by the Rio Grande, it is everyone’s responsibility to be aware of how these diseases are transmitted, and how to avoid becoming infected by them. In addition to the information below, answers to your public health questions can be obtained by calling the Los Alamos Public Health Office at 662-4038 or the Los Alamos Resource Line at 699-5969. The NM Department of Health can be reached at 827-0006.


Hantavirus is spread through contact with rodent feces, urine, or saliva. The most common carrier in New Mexico is the deer mouse, which is found throughout Los Alamos County. The snow and rain of the past winter is likely to increase the food supply for deer mice and other rodents, resulting in an increase in numbers of rodents carrying hantavirus. While hantavirus can be fatal, if caught early it is treatable. Most importantly, before entering a building or vehicle that that has been closed up for a while, air it out for at least 30 minutes. Please see this NM Department of Health link to learn more about symptoms and prevention of hantavirus: NMDOH Hantavirus. Or visit the County Customer Care Center to obtain a brochure.


Plague is spread by infected fleas that have fed off wild animals such as squirrels, rabbits, prairie dogs, coyotes, or bobcats. Dogs and cats that come in contact with dead or infected wild animals can carry infected fleas into one's home and are at direct risk to contract plague. Plague has been found throughout NM, including Los Alamos County. Make sure you pets stay out of rodent holes and use flea powder or a flea collar on them. Plague is treatable if diagnosed early enough; otherwise it is fatal. See this NM Department of Health link for plague prevention information: Plague and How to Prevent It. Or visit the County Customer Care Center to obtain a plague prevention brochure.


West Nile Virus (WNV) has been documented throughout New Mexico. Spread by mosquitoes that bite virus-carrying birds (crows, ravens, and jays), this virus is also fatal to horses. Horse owners and outdoor recreation enthusiasts need to take precautions to avoid this disease. Horses should be vaccinated for equine WNV; the vaccine has proven highly effective. To see the latest maps and charts of WNV activity, and press releases, go to: West Nile Virus Data

Trapping Mosquitoes. Los Alamos County worked with the NM Department of Health (DOH) on a mosquito surveillance program in summer 2005. No mosquitoes sent from LAC tested positive for West Nile Virus. This is not the case for adjacent counties. Wherever they go outside, County residents should assume that WNV is present in some local mosquitoes and take appropriate precautions. Since no community-wide mosquito control program can completely eradicate all mosquitoes from an area, residents must take responsibility for protecting themselves by using insect repellent, wearing long sleeves and long pants, putting screens on windows, avoiding being outside at times when mosquitoes are actively biting, and of course eliminating breeding sites on their own properties.

Mosquitoes breed in pools of stagant and standing water (e.g., flower pots, pet dishes, birdbaths, non-circulated ponds). Less than one cup of water is enough for them to breed. Los Alamos County residents are asked to dump or drain any standing water on their property. For standing water that cannot be easily mitigated, Bti tablets (a mosquito larvacide) offer a safe way to prevent mosquito breeding. Bti can be used in animal water troughs with no danger to animals and in ponds with no danger to fish. Bti tablets can be purchased at hardware stores and some nurseries. The County Parks Division (662-8159) has Bti "care packages" for those who discover standing water pools that cannot be easily drained on their property or elsewhere in the County.

House Pets. The National Animal Poison Control Center states that under no circumstances should insect repellent designed for humans be used on pets. Cats are highly sensitive to these chemicals. Plus, both dogs and cats tend to lick themselves and can ingest toxins, which could harm them significantly more than the West Nile Virus. Use only repellant products marked specifically for use on dogs and cats. So far both species have been fairly resistant to the virus.