A mass rabies exposure event in Utah in 2018 highlights the need for early recognition, public awareness and rapid public health response to the disease.
A fatal case of human rabies in Utah in 2018 has underscored the importance of public education about the risks of the disease and the need for prompt medical attention to mitigate the risks after a possible exposure.
The case, which involved a 55-year-old Utah man who died on November 4, 2018, was the subject of a recent US Centers for Disease Control and Prevention’s (CDC) Morbidity and Mortality Weekly Report. The patient was hospitalized for 15 days before rabies was suspected as the cause of his symptoms. It is the first documented rabies death in the state since 1944.
“The findings from this investigation highlight the importance of early recognition of rabies, improved public awareness of rabies in bats, and the use of innovative tools following mass rabies exposure events to ensure rapid and appropriate risk assessment and provision of post-exposure prophylaxis,” Dallin Peterson, MPH, vectorborne/zoonotic disease epidemiologist at the Utah Department of Health told Contagion®.
The patient had extensive contact with bats prior to his illness, and analysis of postmortem brain stem tissue and cerebellum specimens was consistent with a rabies virus variant associated with Mexican free-tailed bats. The case resulted in potential rabies exposures for 279 people and led to 74 health care workers and 30 family and community members receiving postexposure prophylaxis (PEP) to guard against the infection.
“Because rabies is nearly always fatal once symptoms develop, it is imperative that exposed persons are evaluated promptly for rabies prevention treatment or post-exposure prophylaxis,” Peterson told Contagion®.
The first signs of the disease appeared as neck and arm pain, which the patient attributed to a recent work-related accident and sought chiropractic care on October 17th. As symptoms progressed, the patient was evaluated at an emergency department for pain, muscle spasms, a burning sensation and numbness in the palm of his right hand and later transported by ambulance to a hospital with ongoing pain and muscle spasms along with shortness of breath, tachypnea, lightheadedness, and an inability to sleep or drink fluids.
He was intubated, developed a fever and became comatose on October 25th. Autoimmune encephalitis was suspected, and the patient received corticosteroid treatment. On November 3rd, an infectious disease physician noted the patient’s spasms when swallowing, suspected the possibility of rabies and notified the Utah Department of Health. The patient died on November 4th, serum, CSF, skin biopsy, and saliva were sent to CDC for testing, and rabies was confirmed.
The case highlighted a need to increase awareness about the potential risks of contact with bats, which are the main source of rabies in the United States and the only known rabies reservoir in Utah.
“NEVER handle a bat with bare hands. If you are bitten by a bat, immediately wash the wound and contact your health care provider, local or state health department,” Peterson told Contagion®.
Upon confirmation of rabies, the Utah Department of Health implemented an Incident Command System to determine the source of the infection, identify exposure risk to others using an online survey, coordinate post-exposure prophylaxis, and spread awareness about the risk.
While no bites were noted, family members reported that many bats had occupied the patient’s attic and were frequently found in his bedroom, where he often removed them with his bare hands.
“Public health continues to conduct surveillance for rabies infected animals, recommend proper rabies vaccination for domestic animals, collaborating with health care providers when recommending post-exposure prophylaxis to exposed persons, and educating the public to avoid touching wild animals posing as a rabies risk,” Peterson told Contagion®.
In 2018, the CDC announced efforts to develop a rapid diagnostic test for rabies, dubbed LN34 that can deliver results in 2 hours. The virus is most common in Africa and Asia, and about 60,000 people die each year as a result of rabies infection, which is most commonly spread through contact with infected animals. The CDC said fewer than 10 documented cases of human survival clinical rabies have been reported.
Current rabies vaccines are complex and costly and reserved for people at high risk of infection. Work is underway to develop a more effective rabies vaccine, adding a protein that targets the immune system’s B cells.
Rabies was listed among the top 8 zoonotic diseases of most concern in the United States, according to a report from the CDC and its US government partners.