Spread of adenovirus to geographically dispersed military installations, May-October 2007.

In mid-May 2007, a respiratory disease outbreak as-
sociated with adenovirus, serotype B14 (Ad14), was rec-
ognized at a large military basic training facility in Texas.
The affected population was highly mobile; after the 6-week
basic training course, trainees immediately dispersed to ad-
vanced training sites worldwide. Accordingly, enhanced sur-
veillance and control efforts were instituted at sites receiving
the most trainees. Specimens from patients with pneumo-
nia or febrile respiratory illness were tested for respiratory
pathogens by using cultures and reverse transcription–PCR.
During May through October 2007, a total of 959 specimens
were collected from 21 sites; 43.1% were adenovirus posi-
tive; the Ad14 serotype accounted for 95.3% of adenovirus
isolates. Ad14 was identifi ed at 8 sites in California, Florida,
Mississippi, Texas, and South Korea. Ad14 spread readily to
secondary sites after the initial outbreak. Military and civilian
planners must consider how best to control the spread of
infectious respiratory diseases in highly mobile populations
traveling between diverse geographic locations.
Adenovirus (Ad)–associated acute respiratory dis-ease (AdARD) epidemics have been widely reported
among recruits at US Department of Defense (DoD) train-
ing centers (1–5). Vaccines targeting Ad4 and Ad7, the
most common serotypes associated with these illnesses,
were used among United States military trainees from 1971
through early 1999, when the supply was exhausted follow-
ing cessation of vaccine production in 1996 (1). Because
of the historically high negative effects of respiratory dis-
ease and the discontinuation of vaccine, the DoD initiated
a population-based, active surveillance program in 1996
to track ARD activity among recruits at 8 military train-
ing centers, including the Air Force’s only recruit training
center at Lackland Air Force Base (AFB) in San Antonio,
Texas (1,6,7).
Lackland AFB admits 400–800 new basic military
trainees (BMTs) per week; ≈35,000 BMTs graduate annu-
ally. BMTs are assigned to fl ights of 45–65 persons during
the 6.5-week training program. All fl ight members train,
eat, and sleep as a unit and are housed in 1 large open-bay
facility. According to DoD surveillance data, during Janu-
ary 2005–January 2007 Lackland AFB experienced rela-
tively mild ARD activity among BMTs; rates ranged from
0.1–0.7 cases per 100 recruit-weeks (US Naval Health Re-
search Center, unpub. data). No adenovirus-positive speci-
mens from Lackland AFB were serotyped during 2005, and
only 4 were serotyped during 2006; serotypes included 1
Ad21, 1 AdC, and 1 Ad3. One specimen showed an Ad14/
Ad21 co-infection (8). Adenovirus serotype B14 (Ad14)
was detected at Lackland AFB for the fi rst time in 2006;
in that same year, Ad14 was also detected at 3 other DoD
training centers (8).
Beginning in February 2007, an outbreak of respira-
tory illness associated with Ad14 occurred among Lack-
land AFB BMTs. During the height of the outbreak in June
2007, ARD rates exceeded 2.0 cases per 100 recruit-weeks
Spread of Adenovirus to
Geographically Dispersed Military
Installations, May–October 2007
Jill S. Trei,1 Natalie M. Johns, Jason L. Garner, Lawrence B. Noel, Brian V. Ortman, Kari L. Ensz,
Matthew C. Johns, Michel L. Bunning, and Joel C. Gaydos
Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 16, No. 5, May 2010 769
1Current affi liation: Allina Hospitals & Clinics, Minneapolis, MN,
USA.
Author affi liations: United States Air Force School of Aerospace
Medicine, San Antonio, Texas, USA (J.S. Trei, N.M. Johns, J.L.
Garner, M.C. Johns); Air Education and Training Command, San
Antonio (L.B. Noel, B.V. Ortman); Sheppard Air Force Base, Wich-
ita Falls, Texas, USA (K.L. Ensz); Lackland Air Force Base, San
Antonio (M.L. Bunning); and Armed Forces Health Surveillance
Center, Silver Spring, Maryland, USA (J.C. Gaydos)
DOI: 10.3201/eid1605.091633

RESEARCH
(Naval Health Research Center, unpub. data). Most cases
involved only mild, acute, febrile, respiratory illness. How-
ever, during April–October 2007, 27 patients were hospital-
ized with pneumonia and more severe sequelae; some pa-
tients required intensive care. All these patients were found
to be adenovirus positive, and 20 (74.1%) had positive tests
for the Ad14 subtype. The recognition of these more severe
cases prompted an investigation and enhanced surveillance
to describe the clinical and epidemiologic characteristics of
Ad14 in this population. Laboratory results from early in
the investigation indicated that 63% of ARD-related respi-
ratory specimens collected from BMTs were positive for
adenovirus and that 90% of adenovirus infections were the
Ad14 subtype (9). Most BMTs became ill with adenovirus
in training weeks 4 and 5 (US Naval Health Research Cen-
ter, unpub. data) and may have still been infectious after
graduation because virus shedding can occur in respiratory
secretions and feces for several weeks (10–12).
We modeled the transmission of Ad14 through 2 hy-
pothetical fl ights containing 50 BMTs each (Figure 1) by
using data based on actual laboratory results and epidemio-
logic fi ndings from Lackland AFB; our model indicated
that >50% of BMTs, during the height of the outbreak,
were infected with Ad14 over the course of the 6.5 week
training period (9; Naval Health Research Center, unpub.
data). At the end of basic training, with the conservative
assumption that recovering patients shed virus for up to 1
month, ≈28% of BMTs were still infectious at graduation
and in the following days or weeks. Given the likelihood
that some BMTs were still ill or shedding Ad14 after com-
pleting basic training, response and control efforts had to
account for the high mobility of this population.
Following graduation, students immediately dispersed
to >130 secondary DoD sites for advanced training (Figure
2); most went to a few large Air Force training centers in
the United States, while a few went to smaller sites world-
wide. Secondary training sites, including Sheppard AFB
(Wichita Falls, TX, USA), Goodfellow AFB (San Angelo,
TX, USA), and Keesler AFB (Biloxi, MS, USA), began
reporting increased ARD among their trainees in mid to
late May 2007. We report the spread of Ad14 to secondary
training installations and subsequent response efforts, fol-
lowing the Lackland AFB outbreak, from May 25 through
October 31, 2007.
Methods
Surveillance
In late May 2007, enhanced, active ARD surveillance
was initiated at 12 military installations that received basic
training graduates, including 5 Air Force secondary train-
ing sites that received the most graduates from Lackland
AFB: Sheppard AFB, (28.4% of BMT graduates); Keesler
AFB, (16.4%); Goodfellow AFB, (3.8%); Hurlburt Field,
Florida (1.8%); and Brooks City-Base, Texas (0.7%). In
total, the 12 sites participating in enhanced surveillance
efforts received 54.2% of BMT graduates moving to non–
Lackland AFB sites for their secondary training.
Staff from the US Air Force School of Aerospace
Medicine (USAFSAM) sent respiratory specimen collec-
tion kits and educational materials to the secondary sites
that had cases, created a website to disseminate informa-
tion, and encouraged participation through regular email
correspondence. Investigators at USAFSAM enhanced sur-
veillance efforts by directing efforts to sites with suspected
cases but decreasing or few specimen submissions.
Nasal wash, nasopharyngeal swab, and oropharyngeal
(OP) swab specimens were collected from patients meeting
the ARD case defi nition May 25–October 31, 2007, and
sent to USAFSAM in viral Universal Transport Medium
(Copan, Brescia, Italy). The ARD case defi nition included
fever of >100.5°F with a cough or sore throat or evidence
of pneumonia. Routine patient surveys that accompanied
laboratory specimens were reviewed to obtain patients’
demographic data, signs and symptoms, additional clinical
information, travel history, and lost training days.
Additionally, staff from USAFSAM and the Air Edu-
cation and Training Command headquarters coordinated
the public health response and provided guidance on pre-
vention, enhanced surveillance, and control efforts. Sites
not included in initial enhanced surveillance efforts were
also invited to send specimens collected from patients
whose conditions met the case defi nition. By using labo-
ratory surveillance data, weekly ARD and AdARD trends
were tracked at the 3 main sites reporting increased ARD,
Sheppard AFB, Keesler AFB, and Goodfellow AFB.
Laboratory Methods
Specimens were tested by traditional viral culture,
770 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 16, No. 5, May 2010
Figure 1. Evolving adenovirus
subtype B14 incidence rate
per 100 US Air Force basic
military trainees over 6.5 weeks
of basic training, based on
epidemiologic and laboratory
surveillance data. Red circles,
acutely ill; yellow circles,
recovering/possibly infectious;
blue circles, well.

Spread of Adenovirus to Military Installations
shell vial culture (R-Mix; Diagnostic Hybrids, Athens, OH,
USA), and, beginning July 25, 2007, reverse transcription–
PCR (RT-PCR) for subtype B14. Most adenovirus culture–
positive specimens submitted between May 26 and July 25,
2007 were tested for Ad14 after the test capability became
available. Viral and shell vial culture identifi ed adenovirus,
infl uenza, parainfl uenza viruses 1–3, respiratory syncytial
virus, and rhinovirus, as well as herpes simplex virus 1 and
enterovirus after additional evaluation. Tube cultures were
examined for 10 days for cytopathologic effects, and cells
from the shell vial cultures were stained with pooled fl uo-
rescent antibodies and virus-specifi c monoclonal antibodies.
The procedure and hexon-specifi c oligonucleotides for the
adenovirus B14-specifi c monoplex RT-PCR were adapted
from a US Naval Health Research Center protocol (8,13). On
nasal wash and OP swab specimens and adenovirus isolates,
DNA was extracted from the transport media and amplifi ed
by RT-PCR. The resulting RT-PCR products were then puri-
fi ed by using Millipore (Billerica, MA, USA) microcolumns
and subsequently analyzed by agarose gel electrophoresis,
DNA sequencing, or both. The analyte-specifi c reagent
(ASR) primers and laboratory-developed diagnostic assay
were used in accordance with requirements specifi ed by the
College of American Pathologists for use as part of molecu-
lar diagnostics testing performed at USAFSAM.
Prevention and Control
In addition to adopting prevention and control mea-
sures to mitigate transmission within its own training popu-
lation (9), Lackland AFB offi cials initiated actions to re-
duce spread to secondary training sites. Personnel screened
outgoing BMTs from Lackland AFB for fever by placing
chemical temperature dots on the forehead. Students with
a temperature >100.5°F were held back from travel and
housed in a medical-hold dormitory until their measured
temperatures dropped below 100.5°F for 24 hours. Second-
ary training sites also adopted prevention and control mea-
sures to help incoming students and other assigned active
duty members remain as healthy as possible.
Because it typically receives the most BMT graduates,
Sheppard AFB instituted more aggressive case-fi nding pro-
cedures and prevention measures than any other secondary
training site and fully implemented these actions by June
8, 2007, 12 days after enhanced surveillance efforts began.
Their prevention efforts are described here; several other
secondary sites instituted similar practices. All students ar-
riving from Lackland AFB were screened for a measured
fever >100.5°F and administered a questionnaire during in-
processing. Students suspected of having ARD were fur-
ther screened by a healthcare provider and sent to the clinic
for treatment and testing as appropriate. Students with
ARD were issued masks, grouped with other ARD stu-
Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 16, No. 5, May 2010 771
Figure 2. Locations of military sites that received US Air Force
basic military training graduates for secondary training in North
America (A), the Pacifi c region (B), and Europe and the Middle
East (C). Red indicates locations that submitted specimens as part
of adenovirus surveillance. Star in panel A indicates Lackland Air
Force Base, Texas, USA. Maps generated by using TerraMetrics
(www.terrametrics.com).

RESEARCH
dents, placed on quarters (confi ned to their living area and
restricted from participating in all work and leisure activi-
ties), and removed from all training activities. Students on
quarters were not allowed to enter dining halls, and meals
were instead brought to their rooms. Students were reevalu-
ated by a healthcare provider after 24 hours on quarters and
returned to duty if afebrile.
Sheppard AFB mandated that a virucidal cleaning
agent be used several times per day to sanitize high-touch
surfaces in facilities, including dining halls, classrooms,
dormitories, buses, taxis, the post offi ce, and other student-
frequented establishments. In addition, hand washing and
use of hand sanitizer were highly encouraged and closely
monitored.
Upon completion of the training program, outgoing
students were also screened for ARD by using the same
questionnaire and a documented temperature. All students
suspected of having ARD were placed on medical hold and
evaluated by a physician to determine whether treatment
was needed. After 24 hours they were reevaluated and re-
leased to travel if afebrile.
Results
From May 25 through October 31, 2007, USAFSAM
received 959 respiratory specimens from the 12 secondary
training sites that initially participated in enhanced sur-
veillance and from 9 additional sites (Table 1). Adenovi-
rus accounted for 413 (89.8%) of the 460 specimens with
known etiologic agents; the other viruses identifi ed includ-
ed parainfl uenza (31 [6.7%]), infl uenza type A (5 [1.1%]),
respiratory syncytial virus (2 [0.4%]), and enterovirus (1
[0.2%]). Among the specimens that were culture posi-
tive for adenovirus, 358 (86.7%) were tested for Ad14, of
which 341 (95.3%) were positive. Ad14 was identifi ed at 8
secondary sites located in California, Florida, Mississippi,
Texas, and South Korea; collection dates of the fi rst Ad14-
positive specimen at each site ranged from May 30 through
October 30. Most patients (331 [97.1%]) with confi rmed
Ad14 infection were advanced training students, while 9
(2.6%) infections occurred in active duty members outside
the training population, and 1 (0.03%) occurred in a depen-
dent child.
Patient survey data were available for 538 of the 959
(56.1%) patients from whom specimens were collected;
of these, 220 (40.9%) were Ad14 positive. The follow-
ing results are only for those 220 patients with confi rmed
Ad14 infection and available patient survey data (Table
2). Patient ages spanned 17–29 years, though most (183
[84.7%]) patients were 18–22 years of age; the median age
was 19 years. In addition, most (197 [89.5%]) patients were
male. Regarding patient symptoms, the median tempera-
ture recorded was 101.0°F. The most common signs and
symptoms reported by patients were sore throat (90.9%),
chills (83.2%), fatigue (78.6%), cough (78.2%), head-
ache (75.9%), body aches (70.0%), and nasal congestion
(61.4%). One patient was hospitalized with pneumonia
772 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 16, No. 5, May 2010
Table 1. Summary of results from respiratory specimens received from USAF secondary training bases, May 25–October 31, 2007*
Site†
No.
specimens
Adenovirus not otherwise
specified, no. (%) Ad14, no. (%)
Date first Ad14-positive
specimen collected
Altus AFB, OK 2 0 0 –
Andrews AFB, MD 12 1 (8) 0 –
Bolling AFB, DC 1 0 0 –
Brooks City-Base, TX 10 1 (10) 1 (100) Jun 30
Goodfellow AFB, TX 71 37 (52) 19 (51) Jun 1
Hurlburt Field, FL 3 2 (67) 2 (100) Oct 22
Keesler AFB, MS 85 46 (54) 38 (83) May 31
Laughlin AFB, TX 11 2 (18) 0 –
Luke AFB, AZ 3 1 (33) 0 –
Maxwell AFB, AL 23 1 (4) 0 –
Nellis AFB, NV 3 0 0 –
Osan AB, South Korea 6 1 (17) 1 (100) Jun 19
Patrick AFB, FL 2 0 0 –
Randolph AFB, TX 9 1 (11) 1 (100) Oct 30
Scott AFB, IL 9 2 (22) 0 –
Sheppard AFB, TX 683 309 (45) 273 (88) May 30
Tinker AFB, OK 6 2 (33) 0 –
USAF Academy, CO 6 0 0 –
Vance AFB, OK 0 0 0 –
Vandenberg AFB, CA 10 7 (70) 6 (86) Jun 14
Wright-Patterson AFB, OH 4 0 0 –
Total 959 413 (43) 341 (83)
*USAF, United States Air Force; Ad14, adenovirus B14; AFB, Air Force Base; OK, Oklahoma; MD, Maryland; DC, District of Columbia; TX, Texas; FL,
Florida; MS, Mississippi; AZ, Arizona; AL, Alabama; NV, Nevada; AB, Air Base; IL, Illinois; CO, Colorado; CA, California; OH, Ohio.
†All sites located in the United States except Osan AB (South Korea).

Spread of Adenovirus to Military Installations
and recovered fully without complications. A total of 191
(86.8%) patients were placed on quarters. Of the 125 pa-
tients for whom length of quarters information was avail-
able, most (108 [86.4%]) were placed on quarters for 24
hours. In addition, 147 (66.8%) patients had recently trav-
eled; of these, most (143 [97.3%]) had recently traveled
from Lackland AFB.
At the 3 secondary sites receiving the most BMT grad-
uates, Sheppard AFB, Goodfellow AFB, and Keesler AFB,
AdARD incidence rates among active duty personnel were
tracked and compared with concurrent rates calculated at
Lackland AFB (Figure 3). AdARD rates at Lackland AFB
ranged from 0.1–2.0 cases per 100 personnel, with 2 peaks
in June and September 2007. AdARD activity at Sheppard
AFB waxed and waned throughout the surveillance period,
ranging from 0.2–0.8 ARD cases per 100 personnel. The
largest peak of activity occurred on September 22, 2007, 2
weeks following the onset of Lackland AFB’s second wave
of activity. However, this AdARD activity was short lived,
decreasing over a course of 4 weeks to 0.2 cases per 100
personnel. Activity at Goodfellow AFB and Keesler AFB
was highest following the initial peak at Lackland AFB, and
then tapered off. All 3 sites placed ill students on quarters,
which resulted in the short-term removal of >600 students
from training activities. Only 1 person required hospital-
ization for adenovirus-associated pneumonia, at Sheppard
AFB, during this time (0.01/100 trainees for this 23-week
time period). As of October 31, 2007, prevention and con-
trol efforts were terminated at Goodfellow AFB and Kee-
sler AFB but continued at Sheppard AFB.
Discussion
Ad14 spread readily to secondary training sites because
of the rapid mobility of BMTs following their graduation
from basic training. For the most part, the onset of Ad14-
related illness occurred fi rst at sites that received the most
BMT graduates. Although Lackland AFB made a concert-
ed effort to identify and segregate outgoing febrile BMTs,
more than one quarter of the trainees were likely shedding
virus or recovering from illness. In addition, many were
possibly preclinical and incubating adenovirus as they de-
parted Lackland AFB, with illness developing shortly after
arrival at secondary sites.
Although Ad14 was exported continuously to the sec-
ondary sites, neither the ARD rates nor the severity of ill-
ness at those sites reached the levels seen at Lackland AFB.
Control efforts by Lackland AFB that placed febrile BMTs
on medical hold and prevented them from leaving the base
seemed to affect severity of illness at Lackland AFB and
likely reduced the number of ill persons arriving at second-
ary sites. The lower rates of illness at secondary sites may
also have been due to a decreased number of susceptible
persons in the secondary training population, berthing dif-
ferences that resulted in less contact between trainees at
secondary sites, and decreased stress levels among trainees.
Additionally, decreased illness severity at the secondary
training sites may have resulted from the early identifi ca-
tion of patients with suspected cases and their placement
on quarters, allowing for rest and recovery. Illness trends
at Sheppard AFB tracked Lackland AFB ARD activity
most closely, possibly because Sheppard AFB received the
largest proportion of BMT graduates compared with other
secondary training sites and because healthcare personnel
Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 16, No. 5, May 2010 773
Table 2. Demographic data, symptoms, and other information
collected from 220 patients with positive test results for
adenovirus serotype B14, May 25–October 31, 2007*
Parameter Value
Median age, y (range), n = 216 19 (17–29)
Gender
F 23 (10.5)
M 197 (89.5)
Base where stationed
Goodfellow AFB, TX 8 (3.6)
Hurlburt Field, FL 2 (0.9)
Keesler AFB, MS 16 (7.3)
Sheppard AFB, TX 188 (85.5)
Vandenberg AFB, CA 6 (2.7)
Signs and symptoms
Body aches 154 (70.0)
Chest pain 38 (17.3)
Chills 183 (83.2)
Conjunctivitis 24 (10.9)
Cough 172 (78.2)
Diarrhea 42 (19.1)
Dyspnea 36 (16.4)
Earache 60 (27.3)
Fatigue 173 (78.6)
Headache 167 (75.9)
Runny nose 93 (42.3)
Sinus congestion 135 (61.4)
Sore throat 200 (90.9)
Stiffness 89 (40.5)
Vomiting 39 (17.7)
Median clinical temperature 101°F
Placed on quarters 191 (86.8)
Time on quarters, n = 125
24 h 108 (86.4)
48 h 13 (10.4)
72 h 4 (3.2)
Hospitalized 1 (0.5)
Received influenza vaccine 68 (30.9)
Recent travel 147 (66.8)
Recent travel locations, n = 147
Lackland AFB, TX 143 (97.3)
Keesler AFB, MS 2 (1.3)
Albuquerque, NM 1 (0.7)
Panama City, FL 1 (0.7)
*Values are no. (%) except as specified. Complete information not
available for all patients; n values given when below 220. All locations in
United States. AFB, Air Force Base; TX, Texas; FL, Florida; MS,
Mississippi; CA, California; NM, New Mexico.