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Doctors cite climate change for rise in animal bites, U.S. health care costs

Researchers also note that poorer families are at higher risk of animal bites.
Image: An American dog wearing a muzzle
Cultura/Adrianko / Getty Images file

Stanford researchers warn that the number of animal bites is likely to rise amid climate change and developmental pressures.

Rising temperatures are already exposing people in temperate climates to more mosquitoes and ticks, and developmental sprawl is reducing the amount of land available exclusively to animals.

"As available habitat for these animals increasingly overlaps with human development and recreational activities," the researchers wrote in a BMJ news release, "it is expected encounters with animals may increase and could result in increased animal-related injuries."

Dr. Joseph Forrester, the lead researcher of a study published Tuesday in the online BMJ journal Trauma Surgery and Acute Care Open, added, "We've already seen that with tick populations and mosquito populations. We would anticipate over time more people in traditionally temperate climates will be exposed."

If this prediction holds, it will add to the enormous health care costs that already exist. Currently, U.S. health care costs for animal-related injuries exceed $1 billion every year, according to the study.

This estimate excludes doctors' fees, outpatient clinic charges, lost productivity and the costs of rehabilitation, so the actual costs may be higher.

The study also found that the patients most likely to be injured by bites from venomous snakes, spiders and insects were in the lowest 25 percent of household income for their ZIP code.

This poses a major public health problem in children and adults.

Animal bites are most common among people living in rural, resource-poor settings, who subsist on low-cost, non-mechanical farming and other field occupations. Adult victims are often the wage earners or care providers of the family unit, and child victims can suffer lifelong disabilities, intensifying demands on families and communities.

The health impacts of animal bites depend on the type and health of the animal species, the size and health of the bitten person, and accessibility to appropriate health care.

Numerous animal species have the potential to bite humans; however, the most important are those arising from snakes, dogs, cats and monkeys.

“Dog and cat bites are some of the more frequent injuries we see," said Dr. John Torres, emergency medicine doctor and NBC News health correspondent. "Dog bites tend to be on the hands, arms and face, while cat bites are mostly seen on the hands and lower arm areas. Of the two, cat bites are more worrisome because cats have very sharp teeth that can penetrate deep into the tissue. This pushes the bacteria they have in their mouth deep into the wound and can infect the tendons, which cause it to spread more rapidly."

Most animal bites, except any bite on the face, can be treated outside the hospital. In fact, the report found that of all emergency room visits reviewed, only 3 percent of patients were admitted to the hospital, with bites from insects and spiders accounting for a quarter of these admissions.

“Most dog bites, if small, can be treated at home with careful attention paid to any signs of infection, like redness around the wound or pus," said Torres. "With both cat and dog bites if the wound is large enough to need sutures and we believe there's a chance of a bacterial infection developing, we’ll wait between 48 to 72 hours to suture the wound shut, meaning a second visit to the ER or urgent care, although facial wounds and disfiguring wounds are usually sutured immediately."

Closing a potentially infected wound too early can seal in the bacteria, causing an abscess to form.

Signs of an infected bite wound include:

  • Swelling
  • Redness
  • Warmth
  • Continued pain beyond 24 hours
  • Drainage from the wound

If these develop, seeking treatment at an urgent care clinic or emergency room is highly recommended. Patients should provide a detailed description of the animal's appearance, behavior, and general health, and any known rabies or tetanus vaccine status, to receive proper treatment.