Issue
Number 585
March 3, 2006
CONTENTS OF THIS ISSUE
- Unprotected People #84: Mississippi boy dies from
rabies; exposure to bats around home is likely source
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March 3, 2006
UNPROTECTED PEOPLE #84: MISSISSIPPI BOY DIES FROM RABIES; EXPOSURE TO BATS
AROUND HOME IS LIKELY SOURCE
The Immunization Action Coalition (IAC) publishes articles about people who
have suffered or died from vaccine-preventable diseases and periodically
devotes an IAC Express issue to such an article. This is the 84th in our
series.
On September 27, 2005, a previously healthy 10-year-old Mississippi boy died
from encephalitis later attributed to rabies. Following his death, this case
was referred to CDC's Unexplained Deaths Project. Serum and cerebrospinal
fluid collected from the boy when he was living led to a diagnosis of
rabies. This was the only case of human rabies diagnosed in the United
States in 2005.
The presence of bats in and around the boy's home was the likely source of
the boy's exposure to rabies; in addition, it was reported that the boy had
handled a live bat in spring 2005. Timely prophylaxis after bite, scratch,
or mucous-membrane exposure to wildlife can prevent rabies. Once clinical
signs of rabies develop, postexposure prophylaxis is no longer effective.
This report underscores the need for increasing public awareness of the risk
of rabies after contact with bats and other wildlife.
"Human Rabies—Mississippi, 2005" appeared in MMWR on March 3, 2006. It is
reprinted below in its entirety, with the exception of footnotes. It was
reported by A Palmer, MD, Univ of Mississippi Medical Center, E McVey III,
MD, Baptist Medical Center, Jackson; KM McNeill, MD, PhD, S Hand, Office of
the State Epidemiologist, Mississippi Dept of Health. CE Rupprecht, VMD,
PhD, CA Hanlon, VMD, PhD, M Watts, Div of Viral and Rickettsial Diseases; S
Reagan, MPH, Div of Bacterial and Mycotic Diseases; AS Chapman, DVM, EL Yee,
MD, DK Gross, DVM, PhD, EIS officers, CDC.
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On September 27, 2005, a previously healthy boy aged 10 years in Mississippi
died from encephalitis later attributed to rabies. This report summarizes
the patient's clinical course and the subsequent epidemiologic
investigation, which implicated exposure to bats at the boy's home as the
likely source of rabies. The findings underscore the importance of
recognizing the risk for rabies from direct contact with bats and seeking
prompt medical attention when exposure occurs.
CASE REPORT
On September 11, 2005, the boy had fever and headache. He was evaluated by a
pediatrician on September 13 for a temperature of 102.4 [degrees]F (39.1 [degrees]C)
and was noted to have sensations that the patient described as an "itchy"
scalp. Viral illness was diagnosed, and the patient was advised to return if
symptoms worsened. The patient was taken to a local emergency department
(ED) in the early morning hours of September 15 with ongoing febrile
illness. All laboratory tests and chest radiography ordered were within
normal limits, and the patient was discharged home.
The patient's clinical signs worsened throughout the day, and he returned to
the ED that evening with symptoms of fever, insomnia, urinary urgency,
paresthesia of the right side of the scalp and right arm, dysphagia,
disorientation, and ataxia. He was admitted to the hospital for suspected
encephalitis. A clinical history revealed no known tick bites or contact
with animals other than the family pets.
Upon admission, the patient had a temperature of 100.0 [degrees]F (37.8 [degrees]C)
and a white blood cell (WBC) count of 12,200/microliter (normal:
4,800–13,500/microliter). Analysis of cerebrospinal fluid (CSF) indicated a
WBC count of 226/microliter (normal: 0–5/microliter), protein level of 79
mg/dL (normal: 12–60 mg/dL), and glucose level of 69 mg/dL (normal: 45–75
mg/dL). Serum and CSF samples were obtained for IgG and IgM antibody testing
for West Nile, St. Louis, Lacrosse, and Eastern equine encephalitis (EEE)
viruses.
Shortly after admission, the patient's neurologic status deteriorated
rapidly. His speech became slurred, and he began to hallucinate. He became
increasingly agitated and combative and required sedation. In his agitated
state, the patient bit a family member. The next morning the patient was
transferred to a tertiary care facility. Within hours after transfer, he
became lethargic and was intubated. Serologic tests for West Nile, St.
Louis, Lacrosse, and EEE viruses, Rocky Mountain spotted fever, and
Bartonella spp. were negative. Herpes simplex virus and enterovirus were not
detected in CSF by polymerase chain reaction (PCR), and arbovirus-specific
antibodies were not detected in CSF. Computed tomography scans of the head
with and without contrast were within normal limits. During the next 10
days, the patient continued to worsen and experienced wide fluctuations in
blood pressure and temperature. On September 26, he had onset of cerebral
edema and subsequent brain herniation. Life support was withdrawn, and the
patient died on September 27.
LABORATORY AND PUBLIC HEALTH INVESTIGATION
The case was referred to CDC's Unexplained Deaths Project (UNEX) for
additional diagnostic testing. Clinicians who had treated the patient
suspected EEE and possibly rabies on the basis of the patient's rapidly
progressive encephalopathy. On October 5, CDC diagnosed rabies on the basis
of an increase in rabies-virus–specific IgG antibody titer from 128 to 8,192
in paired sera samples collected on September 16 and 21. Subsequent testing
of CSF demonstrated the presence of rabies-virus–specific antibodies.
Rabies-virus nucleic acid was not detected in CSF by reverse transcription
PCR. No other clinical specimens were available to allow virus
characterization and identification of a likely animal source of infection.
Family members and friends of the patient did not report a definitive animal
bite when queried during the patient's illness. However, after the child's
death, several persons reported that bats were commonly seen outside the
home. On two occasions, dead bats also were discovered inside the home and
attached garage, and a live bat was caught in an apartment above the garage
during the summer of 2005. The child had removed a live bat from his bedroom
and released it outdoors in the spring of 2005.
The child had attended a summer camp in Alabama for several weeks in July.
The camp program included an overnight stay in a nearby cavern used for
tours and special events. Interviews with the camp director and parents of
children who attended the overnight camp-out with the patient revealed no
indication of direct contact with bats at the camp or in the cavern,
although one bat was reportedly observed clinging to the rocky wall inside
the cavern.
Postexposure prophylaxis (PEP) was administered to 23 family members and
friends who possibly had contact with the patient's saliva from August 28
(14 days preceding the first clinical signs of rabies) to the patient's
death on September 27. Interviews with family and friends suggested that the
patient commonly shared food and drink with others, particularly children.
Among 79 healthcare workers evaluated for potential exposure to infectious
body fluids, 32 received PEP, including 19 nurses, four physicians, five
respiratory therapists, two radiology technicians, and two laboratory staff.
Editorial Note
This report describes the only case of human rabies diagnosed in the United
States in 2005 and the first case in Mississippi since 1956. On the basis of
multiple reports regarding the presence of bats in and around the family
home in Mississippi and the observation that the patient had handled a live
bat at his home in the spring of 2005, contact with a bat at the patient's
home was determined to be the likely source of rabies infection in this
case. Bats are the only known reservoir of rabies in Mississippi.
Since 1995, a total of 379 deaths possibly attributed to infectious disease
have been reported to CDC's UNEX. Of these, 131 (35%) have had a probable
etiology identified. The case described in this report represents the first
diagnosis of rabies made for a death reported to UNEX.
Thirty-two healthcare workers received PEP as a result of this case.
Providing health care to a patient with rabies is not an indication for PEP
unless mucous membranes or an open wound are contaminated with infectious
material, such as saliva, tears, CSF, or neurologic tissue. Standard
precautions and adherence to infection-control measures will minimize the
risk for exposure.
During 1980–2004, a total of 56 cases of human rabies were reported in the
United States. Among the 55 cases for which rabies-virus variants were
obtained, 35 (64%) were associated with insectivorous bats, most commonly
the silver-haired and eastern pipistrelle bats. More than half (57%) of
these human cases occurred during August–November, coincident with a
seasonal increase in prevalence of rabid bats detected in the United States.
Despite the substantial number of cases of human rabies attributable to bat
exposure, the importance of these exposures is often overlooked or
under-estimated.
Human rabies is preventable with proper wound care and timely and
appropriate administration of PEP after exposure. PEP is recommended for all
persons with a bite, scratch, or mucous-membrane exposure to a bat unless
the bat tests negative for rabies. When a bat is found in close proximity to
humans, it should be submitted to a public health laboratory for diagnostic
testing, if it can be captured safely. If the animal is not available for
testing, PEP should be administered when a strong probability exists that
exposure occurred. However, if a bat bite is unrecognized or the importance
of the exposure is underestimated, medical intervention might not be sought
and appropriate treatment might not be administered. Once clinical signs of
rabies develop, PEP is no longer effective and a rapid, progressive, and
usually fatal encephalitis ensues.
This report underscores the need for increasing public awareness of the risk
for rabies after contact with bats and other wildlife. Persons bitten by a
potentially rabid animal should immediately (1) wash the wound thoroughly
with soap and water; (2) capture the animal, if this can be done safely
(avoiding direct contact with the animal) and submit it for testing; (3)
report the incident to local or state public health officials; and (4) see a
physician for treatment and evaluation regarding the need for PEP. Persons
should not handle or keep bats as pets and should exclude bats from living
quarters, public places, and structures adjacent to the home. Recognizing
the risk for rabies from any direct exposure to bats and other wildlife is
critical, and persons must seek prompt medical evaluation if exposed.
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To access a web-text (HTML) version of the complete article, go to:
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5508a4.htm
To access a ready-to-print (PDF) version of this issue of MMWR, go to:
http://www.cdc.gov/mmwr/PDF/wk/mm5508.pdf
To read more IAC Unprotected People Reports, go to:
http://www.immunize.org/stories
DISCLAIMER: The Immunization Action Coalition (IAC) publishes Unprotected
People Reports for the purpose of making them available for our readers'
review. We have not verified this report's content, for which the authors
are solely responsible.
DO YOU KNOW OF PUBLISHED ARTICLES ABOUT UNPROTECTED PEOPLE? Please let us
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