By Annette M. Boyle
ABERDEEN PROVING GROUND, MD – While adopting a stray dog or a wild monkey might seem to be a relatively harmless way to boost a military unit’s morale, in countries such as Afghanistan, a nip or exposure to saliva from such an animal can be deadly.
Following the death in 2011 of Spc. Kevin Shumaker from a rabid dog’s bite incurred while deployed in Afghanistan, the Army launched a widespread public-awareness campaign, cracked down on pets or mascots kept on base in Afghanistan and emphasized the risk of rabies in pre-deployment briefings and post-deployment evaluations.
“It is important to note that rabies screening has been in place in some form for every deployment over the past several decades,” Lt. Col. Laura Pacha, MD, disease epidemiology program manager at the U.S. Army Public Health Command told U.S. Medicine. “However, after the 2011 rabies death the Army experienced, DoD modified the questions to make them more explicit.”
In addition, the Army specifically sought out all deployed personnel who had possible animal exposure that occurred after March 1, 2010, and who “had no medical evaluation or incomplete/undocumented evaluation or post-exposure prophylaxis (PEP) following the exposure incident,” according to the public health command’s Rabies Prevention Outreach Program Information for Providers.
As a result of these changes, exposure reports skyrocketed. From 2001-2010, U.S. servicemembers reported 643 animal bites, according to the national Centers for Disease Control and Prevention (CDC). However, “8,577 individuals either had theater medical evaluation for a potential rabies-risk encounter or indicated concern about an animal bite on a post-deployment health assessment” that occurred between March 2010 and September 2011, Pacha said. “Over 300 other individuals were contacted as a result of hotline calls, unit recalls, and soldier redeployment medical processing referrals.”
Following evaluation of their risk and prior treatment, 262 individuals received PEP for these encounters with potentially rabid animals.
Rare in United States
Encounters with potentially rabid animals may have been underreported in the decade before the public-awareness campaign because rabies is extremely rare in the United States. In fact, Shumaker’s death in New York eight months after he returned from Afghanistan was the only reported death from rabies in the nation in 2011. It also was the first documented death from rabies in the DoD in more than 40 years.
“While rare in the developed world with near-universal vaccination of domesticated companion animals such as dogs and cats, over 50,000 human deaths from rabies occur worldwide each year, more than 90% due to bites from rabid dogs,” Pacha cautioned.
But dogs are not the only risk. Other medium to large mammals also can spread rabies to humans, including cats, bats, foxes, skunks, raccoons, mongooses and jackals. Rabbits, hares and small rodents such as mice, rats and squirrels rarely have rabies and are not known to transmit the infection to humans.
Notably, infected animals might not be frothing at the mouth or particularly aggressive. Rabid animals can appear and behave perfectly normal, even cute.
In Afghanistan, dogs were responsible for 50% of the reported bites from 2001-2010, according to the CDC, but the second most common source of bites was one not often seen stateside — monkeys.
In a study published recently in Emerging Infectious Diseases, Capt. Luke Mease, MD, MPH, and Katheryn Baker, BSN, MPH, reviewed records of 126 documented bites or exposures to the saliva of potentially rabid animals from September through December 2011 in eastern Afghanistan. As in the previous decade, half the bites were attributed to dogs, but 8% were caused by rhesus macaque (M. mulatta), which frequently are kept as pets in the region.1
Monkeys can transmit more than rabies, Pacha noted. They also may expose servicemembers to Simian herpes B virus, which can be fatal in humans. The CDC adds trauma, bacterial infection and tetanus to the risks from monkey bites.
Mease and Baker found that most monkey bites were treated appropriately, with proper cleansing of the wound, administration of antiviral medications for the herpes B virus and antimicrobials for oral bacteria. In addition, tetanus status was verified or the tetanus vaccine administered and rabies PEP completed.
In those instances when appropriate care initially was not provided, Mease and Baker suggested that “inadequate treatment could reflect insufficient training and lack of familiarity among U.S.-trained health care providers” for treating such bites.
The researchers noted that U.S. military policy accepts both the World Health Organization PEP guidelines of human rabies immunoglobulin plus five doses of rabies vaccine and the Advisory Committee on Immunization Practices guidelines of human rabies immunoglobulin plus four doses of vaccine for unvaccinated individuals.
For personnel who are vaccinated prophylactically, however, the recommendations are a little different.
“Individuals at high risk of rabies exposure, such as veterinarians, laboratory personnel who may handle specimens from rabies cases, animal handlers and Special Forces personnel, receive rabies vaccination prior to potential exposure,” Pacha said. “A three-shot series induces protective antibodies in most immunocompetent recipients.”
“Other persons with elevated risk of exposure to rabies or who may travel to areas where timely treatment may not be accessible are also considered for pre-exposure prophylaxis,” Pacha added. For previously vaccinated individuals, only the vaccine series is recommended following exposure.
Receiving prompt and appropriate treatment is critical. U.S. Army Public Health Command (USAPHC) notes that “PEP is universally effective in preventing human rabies when administered promptly and appropriately.”
Rabies typically has an incubation period of one to three months, and 90% of cases develop within six months of exposure, according to the CDC. USAPHC cautions that symptoms can appear within days or may be dormant up to a year.
While few cases develop after 12 months, in one notable case in Emerging Infectious Diseases, researchers pegged the incubation time at 4.5 to six years.2
1 Mease LE, Baker KA. Monkey bites among US military members, Afghanistan, 2011. Emerg Infect Dis [Internet]. 2012 Oct.
2 Johnson N, Fooks A, McColl K. Reexamination of human rabies case with long incubation, Australia [letter]. Emerg Infect Dis [serial on the Internet]. 2008 Dec.