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OCR for page 223
RiSk Of Transmissible Spongiform
Encepha/opathies to the U.S. Military
U.S. forces are continually deploying around the globe. More than
250,000 military personnel) were deployed to more than 130 for
eign countries on March 31, 2003 (DOD, 2003), including several
countries where bovine spongiform encephalopathy (BSE) had been re-
ported and where variant Creutzfel~t-Takob disease (vCTD) subsequently
occurred. In addition, U.S. forces are frequently accompanied by their fami-
lies when they are deployed on noncombat missions over an extended pe-
riod. As a result, U.S. military personnel and their families deployed to
countries having reported the occurrence of BSE were at increased risk of
exposure to BSE-contaminated food products for several years starting in
the early 1980s. Likewise, deployed U.S. military personnel may receive
blood transfusions if they are injured in combat or under other circum-
stances. These two factors exposure to BSE-contaminated food and expo-
sure to BSE-contaminated blood products constitute the focus of this chap-
ter. Specifically, we examine how much risk is faced by U.S. forces of
acquiring a foodborne BSE infection and under what circumstances that
risk would occur. Additionally, we evaluate the risk of acquiring a TSE
from a blood transfusion administered to a deployed member of the U.S.
forces being treated for trauma or other emergency condition.
iThis figure excludes the number of military personnel participating in Operation Iraqi
Freedom.
223
OCR for page 224
224
ADVANCING PRION SCIENCE
RISK OF EXPOSURE TO BEEF PRODUCTS
CONTAINING BSE INFECTIVITY
Department of Defense Military Food Supply System
In assessing the military's risk of exposure to beef products containing
BSE infectivity, a brief description of how food is supplied to military per-
sonne! is appropriate. All beef products supplied to U.S. forces come from
approved suppliers. The forces receive a majority of their food, including
beef and beef products, from U.S. producers. Food is prepared and pre-
packaged in a variety of ration sets served during training or combat opera-
tions. Some meals are served fresh, and regulations dictate that vendors
selling food destined for troops be closely inspected and regulated.2
Commanders of U.S. military units have the authority to purchase local
food products, including beef. A commander might exercise this authority
if his or her troops had been eating prepackaged rations for an extended
period of time to offer variety and to maintain high morale. If local beef
were purchased in a country where BSE had been reported,3 the troops who
consumed it would be at risk of exposure to BSE, although the practice of
procuring local beef is the exception rather than the rule. Current policy
prohibits the purchase of beef from a country reporting cases of BSE, but it
does not prohibit the purchase of beef from other countries, as long as the
source is approved by the Department of Defense (DOD) Veterinary Ser-
vices. Some beef was purchased from the United Kingdom, Italy, Germany,
and Japan before it was recognized as potentially being infected with the
BSE agent.
DOD Commissary Food System
Military personnel, as well as their families, have access to beef prod-
ucts through several other outlets as well. The first is the commissary sys-
tem. Commissaries are military supermarkets stocked primarily with food
products from the United States. U.S. producers generally supply all the
beef sold in the commissaries. In some European countries reporting BSE,
however, some beef sold in commissaries was procured locally for certain
periods of time. From 1980 to 1989, the monthly foreign beef procurement
from non-U.S. suppliers averaged 2.5 million pounds. Of this amount, 35
2U.S. Army Regulation AR40-657 (1997); U.S. Navy Regulation NAVSUPINST4355.4F
(1997); U.S. Marines Regulation MCOP10110.316 (1997).
3EDITORS' NOTE: After this report was completed, the first U.S. case of BSE was identi-
fied in Washington State and was announced to the public on December 23, 2003.
OCR for page 225
RISK OF TSEs TO THE U.S. MILITARY
225
percent was from the United Kingdom and 65 percent was from other Eu-
ropean countries. Of the product from the United Kingdom, approximately
300,000 pounds was delivered each month to commissary stores north of
the Alps (Germany, Belgium, Netherlands, and the United Kingdom) and
approximately 575,000 pounds was delivered each month to commissary
stores south of the Alps (Italy, Spain, Greece, and Turkey). Supply contracts
for 112 stores located on 21 delivery routes were written on a monthly
basis. Thus, the source of supplies for a specific store could and did change
monthly. Records of specific delivery dates and locations no longer exist.
Thus it is impossible to determine which stores received beef from the United
Kingdom, but it must be assumed that all stores received some product
from that country. These contracts were for carcass beef, which was split
into forequarters and hindquarters at the packinghouse and further pro-
cessed into cuts for retail sale in the meat market of the commissary store.
In 1990 the Beef to Europe Program was initiated for commissary stores
north of the Alps. This program, which was congressionally mandated and
not related to BSE, entailed the shipment of boxed beef (vacuum-packaged
wholesale cuts) of U.S. origin to Europe. During a supply failure, beef was
purchased on an emergency basis within Europe. Of these emergency con-
tracts, 99 percent were given to German meat packers. All commissary
stores within the United Kingdom, with the exception of the commissary in
E3zell, Scotland, participated in the Beef to Europe Program.
Shipments to the E3zell Commissary and areas south of the Alps con-
tinued to be carcass beef from the United Kingdom. These contracts were
converted to boxed beef in 1994. After March 1996, all procurement of
beef from the United Kingdom ended, and in March 2000, all procurement
of European beef stopped.
Other Sources of Beef Products
Beef products are also sold to members of the U.S. military and their
families at post exchanges (PXs), which are located on U.S. military posts
and bases. The Army and Air Force Exchange Service (AAFES), which man-
ages the exchange system, is not able to provide estimates of the total num-
ber of pounds of beef procured in Europe during the same time frames
mentioned above. They did, however, use cuts of carcass meat and distribu-
tion procedures similar to those described above for the commissary sys-
tem. AAFES food service outlets used European beef, and approximately 20
percent of this beef was from the United Kingdom.
A third outlet for the purchase of beef by members of the U.S. military
and their families is hamburger franchises. Before the reduction of troop
strength in Europe, more than 50 hamburger franchises were operating as
concessions. These operations used preformed patties from the United King-
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226
ADVANCING PRION SCIENCE
dom through 1989. From 1990 to March 2000, either U.S. beef was used,
or beef was ground in an AAFES-operated facility in Germany; the latter
was a combination of U.S. beef and beef from European countries other
than the United Kingdom. Between March 1996 and March 2000, most of
the beef originated from European countries without cases of BSE, and
some came from the United States. Since March 2000, the beef has been of
U.S. or non-European origin.
Risk of Exposure to BSE Agent
Members of U.S. forces, including their family members, commonly
enjoy the local culture and consume locally prepared foods while they are
stationed overseas. They purchase food in local markets and dine in local
eating establishments. However, the majority of food they consume comes
from either the system used to feed troops or the commissary system.
The greatest period of risk for exposure to BSE-contaminated beef prod-
ucts occurred between 1980 and 1996 in the United Kingdom. For conti-
nental Europe, that period of risk was extended beyond 1996. In the early
1980s, the BSE outbreak was not apparent, yet cattle were infected with
BSE. Effective controls to prevent further contamination of the food supply
were put in place iteratively, first in the United Kingdom and then through-
out other European countries. During that period, 4,428,572 military per-
sonne! and their family members were potentially exposed to BSE-contami-
nated beef products (Table 9-11.
U.S. military members and their families living in the United Kingdom
and Europe between 1980 and 1996 were at increased risk of exposure to
the BSE agent as a result of their consumption of locally procured beef or
their consumption of beef in local eating establishments as compared with
the risk to their counterparts in the United States. The committee judged,
however, the risk of acquiring foodborne-associated vCJD to be relatively
small compared with that of the local population due to the lesser con-
sumption local beef and the shorter period of exposure. Notification and
TABLE 9-1 DOD Active Duty Personnel and Dependents in Europe
Period Number of Number of Total Number
Active-Duty Personnel Dependents of Individuals
1980-1996
1,932,179
2,496,393
4,428,572
January 1, 2001 215,778 317,231 533,009
SOURCE: Severin (2002).
OCR for page 227
RISK OF TSEs TO THE U.S. MILITARY
227
active prospective surveillance are not warranted for these military mem-
bers or their families. However, the committee encourages passive moni-
toring of the incidence of Creutzfel~t-Takob disease (CTD) among military
personnel.
Recommendation 9.1: Use existing passive surveillance systems to
monitor the incidence of Creutzfel~t-lakob disease and variant
Creutzfel~t-lakob disease among individuals receiving medical care
from the health systems of the U.S. Department of Defense and the
Department of Veterans Affairs. [Priority 314
RISK OF TSE INFECTION FROM BLOOD PRODUCTS
Blood transfusions could also place deployed forces at theoretical risk
of infection by the agent of BSE or other transmissible spongiform encepha-
lopathies (TSEs) (see also Chapters 5 and 71. In a situation in which a de-
ployed service member is wounded or otherwise injured and needs a blood
transfusion, where does that blood come from and what is the likelihood
that it contains the agent of vCTD or another TSE?
The DOD Blood Supply System
DOD's blood supply is under the management of the Armed Services
Blood Program (ASBP). The collection, processing, tracking, storage, and
distribution of blood are closely managed (DOD, 19961. The majority of
blood used by U.S. forces is collected at 24 blood collection sites: 18 sites in
the United States and 6 sites overseas (Sparks, 20021. More than 90 percent
of the blood collected at these sites comes from active-duty service members
(Sparks, 20021. Some of the military's blood is frozen for longer-term stor-
age and use. This stockpile was collected in the early 1990s, before the
current blood donation deferral policy was in place (personal communica-
tion, LTC R. D. Sylvester, Armed Services Blood Program, November 5,
2002) and would be used only in a major military contingency situation in
which fresh blood was unavailable.
The U.S. military deploys its own health care system in support of U.S.
forces overseas. That system includes medical providers, fixed and mobile
hospitals, and medical supplies, including blood. In general, any blood given
to a deployed service member would be collected and controlled by ASBP.
Thus, the committee concluded that the risk that a service member would
4The committee denotes each recommendation as priority level 1, 2, or 3 based on the
criteria and process described in the Introduction.
OCR for page 228
228
ADVANCING PRION SCIENCE
be transfused blood from a donor having preclinical vCTD would be quite
remote.
Under some circumstances, blood products are supplied to U.S. facili-
ties by the host nation. Examples of such blood products are platelets, which
have a very short shelf life, and products whose supplies are exhausted or
unavailable. Additionally, U.S. forces deployed overseas use local emergency
rooms or hospitals when medical care is not available from the DOD health
care system. Should a U.S. service member have an injury serious enough to
warrant a blood transfusion from a local hospital in a country reporting
BSE, there would be a theoretical risk of exposure to the vCTD agent in the
blood, but those situations are uncommon.
DOD Blood Donation Deferral Policies
Although the risk of a member of the deployed armed forces acquiring
a TSE infection from a blood transfusion is presumed to be very low, indi-
viduals who were deployed to Europe during the period of risk are not able
to donate blood, according to DOD policy (Sparks, 20021. The Food and
Drug Administration (FDA) and the American Red Cross have similar blood
donation deferral policies (see Table 9-21. This policy results in the deferral
of 18 percent of DOD donors and has placed a significant burden on DOD's
ability to maintain its blood supply. However, special recruiters at blood
donor sites have increased collections by 9 percent, helping to offset these
losses (Sparks, 20021. If an antemortem blood test were available and sensi-
tive enough to detect prions in blood, it might be possible to return to the
blood donor pool more than 4 million donors whose DOD service in Eu-
rope precludes them from donating blood, as well as half a million deferred
civilians (5 percent of the national blood donor pool) (Sparks, 20021.
SUMMARY OF OVERALL RISK
This chapter summarized the risk to deployed U.S. forces of acquiring a
TSE as the result of eating a food product or receiving a blood product
containing TSE infectivity. Both risks are deemed small. Nevertheless, the
level of risk is unknown, so the precaution of deferring individuals who
were potentially exposed to BSE-contaminated meat from donating blood
is justified. Research clarifying the infectious potential of blood products as
a vehicle for transmitting prions would help immensely in addressing this
issue.
OCR for page 229
RISK OF TSEs TO THE U.S. MILITARY
TABLE 9-2 Comparison of Deferral Policies
229
Assistant Secretary
of Defense for
Health Affairs (DOD)
U.S. Food and
Drug Administration
American Red Cross
United Kingdom (UK)
Cumulative time 2 3
months 1980-1996
Transfusion in UK
1980-present
Cumulative time
2 3 months 1980-1996
Transfusion in UK
1980-present
Europe and otI7er countries associated witI7 BSE by USDA
Cumulative time 2 3 months
1980-presenta
Transfusion in UK
1980-present
Europe 1980-present Europe 1980-present All of Europe, regardless of
cumulative time cumulative time 2 5 years USDA rating, cumulative time
2 5 years (applies to (applies to DOD after 1997) 2 6 months 1980-present
DOD after 1997)
DOD stationed in DOD stationed in Europe
Europe 1980-1996 from 1980-1990 (north of
cumulative time the Alps) cumulative
2 6 months. time 2 6 months.
DOD stationed in Europe
from 1980-1996 (south
of the Alps) cumulative
time 2 6 months.
aThe American Red Cross recently changed its policy to defer donations of blood from
individuals who spent 3 months or more living in the United Kingdom between 1980 and 1996
(personal communication, R. Dodd, The American Red Cross Holland Laboratory, June 27,
2003).
NOTE: USDA = U.S. Department of Agriculture.
SOURCE: Sparks (2002).
REFERENCES
DOD (U.S. Department of Defense). 1996. Department of Defense Instruction 6480.4. Wash-
ington, DC: Armed Services Blood Program, DOD.
DOD.2003. Active duty military personnel strengths by regional area and by country (309A).
Washington, DC: Statistical Information Analysis Division Personnel, Directorate for
Information Operations and Reports, Washington Headquarters Services, Department of
Defense. [Online]. Available: http://www.dior.whs.mil/mmid/M05/hstO303.pdf.html [ac-
cessed November 21, 2003].
Severin SR. 2002. Protecting tile DoD Food Supply from TSEs. Presentation to the IOM
Committee on Transmissible Spongiform Encephalopathies: Assessment of Relevant Sci-
ence, Meeting I. Washington, DC.
Sparks RA. 2002. Armed Services Blood Program vCJD Update. Presentation to the IOM
Committee on Transmissible Spongiform Encephalopathies: Assessment of Relevant Sci-
ence, Meeting I. Washington, DC.
OCR for page 230
RISK OF TSEs TO THE U.S. MILITARY
TABLE 9-2 Comparison of Deferral Policies
229
Assistant Secretary
of Defense for
Health Affairs (DOD)
U.S. Food and
Drug Administration
American Red Cross
United Kingdom (UK)
Cumulative time 2 3
months 1980-1996
Transfusion in UK
1980-present
Cumulative time
2 3 months 1980-1996
Transfusion in UK
1980-present
Europe and otI7er countries associated witI7 BSE by USDA
Cumulative time 2 3 months
1980-presenta
Transfusion in UK
1980-present
Europe 1980-present Europe 1980-present All of Europe, regardless of
cumulative time cumulative time 2 5 years USDA rating, cumulative time
2 5 years (applies to (applies to DOD after 1997) 2 6 months 1980-present
DOD after 1997)
DOD stationed in DOD stationed in Europe
Europe 1980-1996 from 1980-1990 (north of
cumulative time the Alps) cumulative
2 6 months. time 2 6 months.
DOD stationed in Europe
from 1980-1996 (south
of the Alps) cumulative
time 2 6 months.
aThe American Red Cross recently changed its policy to defer donations of blood from
individuals who spent 3 months or more living in the United Kingdom between 1980 and 1996
(personal communication, R. Dodd, The American Red Cross Holland Laboratory, June 27,
2003).
NOTE: USDA = U.S. Department of Agriculture.
SOURCE: Sparks (2002).
REFERENCES
DOD (U.S. Department of Defense). 1996. Department of Defense Instruction 6480.4. Wash-
ington, DC: Armed Services Blood Program, DOD.
DOD.2003. Active duty military personnel strengths by regional area and by country (309A).
Washington, DC: Statistical Information Analysis Division Personnel, Directorate for
Information Operations and Reports, Washington Headquarters Services, Department of
Defense. [Online]. Available: http://www.dior.whs.mil/mmid/M05/hstO303.pdf.html [ac-
cessed November 21, 2003].
Severin SR. 2002. Protecting tile DoD Food Supply from TSEs. Presentation to the IOM
Committee on Transmissible Spongiform Encephalopathies: Assessment of Relevant Sci-
ence, Meeting I. Washington, DC.
Sparks RA. 2002. Armed Services Blood Program vCJD Update. Presentation to the IOM
Committee on Transmissible Spongiform Encephalopathies: Assessment of Relevant Sci-
ence, Meeting I. Washington, DC.
Representative terms from entire chapter:
cumulative time
