ArticlePDF AvailableLiterature Review

Brucella as a biological weapon

  • Institute of Continuing Medical Education of Ioannina


Brucella has traditionally been considered a biological weapon. It was the subject of extensive offensive research in the past, and still belongs to category B pathogens on most lists. Its propensity for airborne transmission and induction of chronic debilitating disease requiring combined antibiotic regimens for treatment, its abundance around the world and its vague clinical characteristics defying rapid clinical diagnosis are some of the characteristics that apply to the pathogen's weapons potential. Yet minimal mortality, availability of treatment options, protracted inoculation period and the emergence of new, more virulent potential weapons means that its inclusion among agents of bioterrorism is nowadays mainly of historical significance. Nevertheless, in the interest of literacy and of avoiding panic, physicians and the public both should be aware of the most common zoonosis worldwide.
Abstract. Brucella has traditionally been considered a
biological weapon. It was the subject of extensive offen-
sive research in the past, and still belongs to category B
pathogens on most lists. Its propensity for airborne trans-
mission and induction of chronic debilitating disease re-
quiring combined antibiotic regimens for treatment, its
abundance around the world and its vague clinical char-
acteristics defying rapid clinical diagnosis are some of
the characteristics that apply to the pathogen’s weapons
potential. Yet minimal mortality, availability of treatment
options, protracted inoculation period and the emergence
of new, more virulent potential weapons means that its in-
clusion among agents of bioterrorism is nowadays mainly
of historical significance. Nevertheless, in the interest of
literacy and of avoiding panic, physicians and the pub-
lic both should be aware of the most common zoonosis
Keywords. Brucella, brucellosis, bioterrorism.
Brucellosis is an ancient disease. It remains the most
common anthropozoonosis worldwide, inducing an of-
ten chronic, often incapacitating disease with low mor-
tality. Its significance as a potential agent of bioterror-
ism was acknowledged early, and the pathogen remains
on the category B biodefense research list of both the
Centers for Disease Control and Prevention (CDC) [1]
and the National Institute of Allergy and Infectious
Diseases (NIAID) [2]. It is also invariably included on
the non-stratified lists of potential biological weapons
of other organizations, such as the World Health Orga-
nization (WHO), the North Atlantic Treaty Organiza-
tion (NATO), and the Biological and Toxin Weapons
Convention (BTWC). Certain epidemiological, mi-
crobiological and clinical parameters of the pathogen
render it an attractive agent for malicious use. We will
analyze these parameters, along with other aspects that
emerge following a hypothetical deliberate release of
the agent.
The pathogen
Brucella belongs to the genus of a-proteobacteria and
consists of seven species: B. melitensis, B. abortus, B. suis
and B. canis are known to induce human disease, while
B. neotomae and B. ovis are not virulent to humans. B.
pinnipediae and B. cetaceae are marine species pathogens
discovered recently and provisionally named [3] that may
also be human pathogens [4]. The genome of B. melitensis
[5], B. abortus [6] and B. suis [7] has been fully decoded,
and extended active research on the significance of vari-
ous proteins expressed by the bacterium will probably al-
low for better understanding of the unique pathogenetic
processes involved in human brucellosis [8]. Brucellosis
is principally a zoonosis, a common cause of abortions
in sheep and goats (B. melitensis), cows (B. abortus) and
pigs (B. suis). B. canis is a canine pathogen, B. ovis is
also a sheep pathogen, and B. neotomae is found in ro-
dents. Furthermore, though other species, including wild-
life, can serve as the reservoir of Brucella, although the
prevailing subtypes in wildlife may be of minimal hu-
man importance [9], as in France. That is not the case in
United States though, where B. abortus-infected bisons
were recently slaughtered in certain Midwestern states,
Brucella as a biological weapon
G. Pappas
*, P. Panagopoulou
, L. Christou
and N. Akritidis
Institute for Continuing Medical Education of Ioannina (Greece)
Internal Medicine Department, University Hospital of Ioannina, Velissariou 15-19, 45221, Ioannina (Greece),
Fax: +30 26510 49045, e-mail:
Internal Medicine Department, General Hospital ‘G. Hatzikosta’ of Ioannina (Greece)
Online first ❚❚❚
* Corresponding author.
Cell. Mol. Life Sci.
DOI 10.1007/s00018-006-6311-4
© Birkhäuser Verlag, Basel, 2006
Cellular and Molecular Life Sciences
2 G. Pappas et al. Brucellosis and bioterrorism
raising concerns about the cost effectiveness and political
correctness of the whole procedure [10]. Brucella does
not form spores, but it is still significantly environmen-
tally resistant.
Brucellosis is an ancient disease. It induced disease in a
significant number of inhabitants of Pompei [11], and is
possibly the cause, in a bizarre form of ‘divine bioterror-
ism’, of the fifth plague of Egypt, which decimated Egyp-
tian cattle. Yet the disease is also described as incapaci-
tating equine species, and others have suggested that the
fifth plague was in fact anthrax (the sixth plague, which
is a more accurately describes human and animal anthrax
disease, is suggested by some to be smallpox). At the end
of the 19
century, brucellosis was prevalent among Brit-
ish troops stationed in Malta. And although it is tempting
to assume that locals deliberately infected troops by offer-
ing raw goat milk, we know that raw milk was considered
an excellent tool for strengthening patients supposedly
suffering from typhoid. Sir David Bruce, a British Army
officer, was the first to isolate the organism and along
with his coworkers subsequently managed to trace the
epidemiology back to goat milk. He developed the first
serum agglutination test for to diagnose brucellosis [12].
By the beginning of World War II, the medical and veteri-
nary aspects of the disease had been extensively outlined,
and brucellosis emerged as an attractive candidate in the
still premature biowarfare industry. The attractiveness of
Brucella was based on certain combat parameters of the
era: an agent that could caused a protracted incapacitat-
ing disease with minimal mortality would mean that most
of the enemy’s troops would be sidelined by illness, and
a significant percentage of non-infected army members
would be needed to care for them (this percentage would
be higher and implicated for a longer period than the one
needed for dealing with dead bodies, had a more lethal
pathogen been used). Practically every major national
program for offensive biological weapon development
dealt with Brucella. Brucella was one of the agents with
which Japan experimented in the infamous 731 Manchu-
ria Unit before and during World War II. In the United
States, B. suis was the first agent weaponized in 1952,
and extended field testing with B. suis-filled bombs
took place thereafter [13]. Soon though, other, more po-
tent weapons were targeted. In the former Soviet Union,
Brucella was one of the agents developed for offensive
purposes by Biopreparat, the extensive Soviet biological
weapons program. Ken Alibek, a former deputy director
who relocated in United States in 1992 stated that un-
treatable, antibiotic-resistant forms had been developed,
the agent was weaponized both in dry and liquid forms,
production capability ranged at the level of 100 tons of
bacteria and the means to deliver the pathogen had been
extremely sophisticated. As with other agents developed
by the Soviet Union, extended field testing was per-
formed on the island of Vozroshdeniye, in the midst of
the Aral Sea [14]. Despite its historical significance and
attractiveness in the era of traditional combat situations,
by the end of the 20
century interest in Brucella gradu-
ally waned: it is characteristic that Alibek states that Bru-
cella was dropped from the Soviet program in favour of
Burkholderia pseudomallei, which was considered more
potent. Still, as with other aspects of the Biopreparat pro-
gram, questions about the subsequent whereabouts of the
resistant strains developed remain.
Brucellosis, particularly caused by B. melitensis, remains
the commonest zoonotic disease worldwide, and more-
over seems to be relocating and re-emerging in recent
years [15]. Middle Eastern countries as Syria, Iran and
Iraq Figure prominently on a list of endemic countries,
but new foci that have emerged include all the former
communist Asian republics, such as Kazakhstan, Kyr-
gizstan and especially Mongolia. The situation is slowly
improving in the European Union, although the disease
is still endemic in Greece, Spain, Portugal and southern
Italy. International travel and the importation of exotic
food from endemic areas account for a limited number
of cases reported annually from brucellosis-free industri-
alized countries. The same stands for the United States,
where most cases appear in states neighboring Mexico, in
patients with Hispanic origin and related to importation
of infected dairy products from the still endemic Mexico
[16]. North Africa remains an endemic area, while the
situation in sub-Saharan Africa cannot be adequately
evaluated; furthermore, other infectious disease-related
priorities exist in these countries. Three important bio-
terrorism-related aspects emerge from the current global
disease status. First, Brucella can be easily obtained
practically anywhere in the world, in contrast with agents
such as smallpox, and thus its use as a biological weapon
could be kick-started rather easily. In that vein one has
to question the rationale behind widely circulated reports
about Iraq obtaining Brucella strains from a US firm at
the end of the 1980s: brucellosis was already endemic in
Iraq during that period, so strains could easily be isolated
from naturally occurring human cases. Second, one has
to note that certain endemic areas coincide with areas
where active foreign army operations have been evolv-
ing; thus, a naturally occurring case in a US soldier in
Iraq could, at least initially, raise concerns about pos-
sible deliberate release. In this context, brucellosis was
related to the development of Gulf War Syndrome (see
following sections). Containment of naturally occurring
Cell. Mol. Life Sci. Multi-author Review Article 3
disease in these areas does not seem feasible at present,
since the disease is related to overall socioeconomic sta-
tus and political factors. The emergence of brucellosis
in Kosovo and Bosnia-Herzegovina in recent years after
lengthy political unrest and extended military operations
and the mechanisms of disease trafficking in the Balkans
is a typical example [14]. The third important aspect is
that of awareness: brucellosis being a rare disease in the
developed world, many physicians and infectious disease
specialists are not familiar with its characteristics, lead-
ing to delayed diagnoses or false alarms [17]. More on
this follows in upcoming sections.
As already stated, Brucella was initially attractive as bio-
warfare partly due to its ability to induce chronic disease.
The pathogenesis of brucellosis is unique, and animal
models often cannot accurately reproduce events evolv-
ing during human infection. Brucella is a Gram-negative
pathogen, yet its surface lipopolysaccharide induces far
smaller immune response comparing with other Gram-
negative bacteria. Brucellae have a propensity for invad-
ing the reticuloendothelial system, practically hiding
inside macrophages and non-professional phagocytes.
In there, they reside in specialized compartments with
acidic environments, and multiply using parts of the cy-
toskeleton, without interrupting cell cycle and function
[18]; on the contrary they are apoptosis inhibitors, thus
creating a frame for eternal survival and replication. Im-
mune response is partly muted by certain Brucella fac-
tors, inhibition of tumor necrosis factor-alpha (TNF-
being a prominent event. Cellular immune responses
predominate [19], although antibody production serves
as a diagnostic tool. It has been long postulated that the
outcome of the disease reflects the equilibrium developed
between the bacterium and the human immune response,
and that relapses and chronic disease should also be
viewed in this context.
Transmission to humans
One important bioterrorism-related characteristic of
Brucella is the small inoculum needed to induce human
disease, traditionally described in the levels of 10–100
microorganisms. The commonest means of Brucella
transmission to humans is by consuming unpasteurized
dairy products as milk and soft cheese. Direct contact
through skin abrasions with infected animal tissues (as in
slaughterhouse workers) is also implicated, but the most
important means of transmission in the context of bio-
terrorism importance is airborne transmission. Brucella
can be easily aerosolized, and when in air, can be easily
transmitted through the airways and induce disease, while
staying for a protracted period in this virulent form. Char-
acteristically, brucellosis is considered the commonest
laboratory-acquired infection worldwide [20], and thus
certain isolation and experimental procedures should be
performed in Biosafety Level 3 (BSL3), and laboratory
workers should be informed ahead of time about the di-
agnostic possibility of brucellosis in order to implement
appropriate diagnostic precautions. Its propensity for
aerosolization and easy spread is another of the impor-
tant bioterrorism-related characteristics of the bacterium.
Using Brucella as a biological weapon through the food
chain could be feasible, but would result in localized clus-
ters of cases: one would have to intervene at a post-in-
dustrial level, since pasteurization kills the pathogen. The
potential for such an approach in order to induce massive
disease is obviously low, but should also be entertained
by policy makers of the area, and is beyond the scope of
this review.
The inoculation period is relatively protracted, especially
when compared with other pathogens considered as po-
tential biological weapons, ranging 9–60 days. This alone
could be a drawback in the context of biowarfare, since
a deliberate release would not lead to a sharp outbreak
curve, but would rather induce a smooth curve of gradual
increase, and subsequent decrease over a period of 1–2
months. Thus, more time would be allowed for authori-
ties to diagnose and intervene, and less public unrest and
health authorities’ burden would be created [21]. Since
deliberate release of a pathogen theoretically aims, at
least partly, at social disruption, Brucella is by far an un-
suitable agent. Still, certain approaches to bioterrorism
risk argue that penetration of infectious sequelae deep
in time might be more important for social disruption in
long term [22], and brucellosis should be re-evaluated in
this context. The possible existence of an inverse relation-
ship between microbial inoculum and inoculation period
should also be further studied.
Inapparent-to-apparent infection ratios cannot be ad-
equately calculated, owing to discrepancies in different
series. A genetic predisposition seems to exist [G. Pappas
et al., unpublished data].
Clinical characteristics
Brucellosis can cause practically any clinical syndrome
[23], and in endemic areas the tagline ‘everything is Bru-
cella until proven different’ might actually be useful. The
commonest syndrome presented is one of a flu-like ill-
ness, with fever that may be protracted (often present-
ing as fever of unknown origin [24]), arthralgia, myalgia,
fatigue and malodorous perspiration. The propensity for
reticuloendothelial system invasion leads often to hepato-
megaly, splenomegaly and lymphadenopathy. Uncompli-
4 G. Pappas et al. Brucellosis and bioterrorism
cated disease is readily responsive to antibiotic treatment.
Complications reported are abundant, the commonest be-
ing arthritis (either peripheral or, often, sacroiliitis) and
spondylitis [25], which can be debilitating and difficult to
treat [26]. The propensity of the pathogen for granuloma
formation can lead to abscess formation in various sites.
Epididymo-orchitis [27], mild hepatitis, rashes and asci-
tes [28] are often reported. The most serious complica-
tions of the disease are neurobrucellosis, which can pres-
ent in various forms [29], and endocarditis, which is the
main cause of mortality (altogether very low) and often
requires surgical intervention [30]. Respiratory complica-
tions in brucellosis are more usual than generally thought;
yet there is no connection between airborne transmission,
the probable route of transmission after deliberate release
and emergence of respiratory complications, as outlined
in a large series of cases [31]. Laboratory characteristics
include cytopenia of varying range and severity [32],
mild increases in serum aminotransferase levels and rela-
tive lymphocytosis.
In pregnancy brucellosis is related to an increased risk of
spontaneous abortion [33], while in childhood the disease
is generally thought to be more benign [34]. The relatively
few data on brucellosis in immunocompromised patients
[35] suggest that clinical severity is not enhanced in this
Chronic brucellosis is an entity much talked about, but
inadequately understood. By the traditionally accepted
definition, the disease is chronic when exhibiting a
course of more than 6 months. Yet chronicity can present
as frequent relapses, residual disease after treatment and
sometimes as persistent behavioral changes accompanied
by ill-defined neurological syndromes, weight loss and
fatigue, in the absence of any laboratory evidence of bru-
cellosis relapse. This syndrome is familiar to brucellosis
specialists; some argue that its nature is autoimmune. It
is a syndrome strikingly familiar to chronic fatigue syn-
drome (CFS), an equally vaguely described syndrome
developed by Gulf War veterans after the first Gulf War.
Brucellosis was endemic in the battlefield area, and fear
of deliberate exposure to Brucella aerosols from the Iraqi
army was also prominent. Thus, brucellosis was one of
the first diagnoses entertained in the approach of CFS.
No significant evidence has emerged, yet one should
remember the long-standing hypotheses on the relation-
ship between Brucella and demyelinating syndromes
[36]. Advances in diagnostic options might help to more
clearly define and understand the exact nature of chronic
brucellosis, and decisively outline the presence or not of
any etiological relationship with CFS.
The clinical presentation of brucellosis being protean,
in the event of a deliberate release a clinical diagnosis
might not be easily achieved. Most patients would ex-
perience a constellation of symptoms also pointing to-
wards other pathogens, such as Francisella tularensis,
Coxiella burnetii and several viruses. Yet establishing of
a clinical diagnosis would be largely related to clinicians’
awareness of the disease, which in turn is influenced
by the effectiveness of educational programs on bioter-
rorism and the endemicity of the agent in the targeted
area. A recent educational US program including a mul-
tiple-choice questionnaire outlined this fact: 15% of par-
ticipating physicians wrongly diagnosed brucellosis in a
patient presenting with severe pneumonia. A co-resident
of the patient had died 4 days earlier with hemoptysis
and dyspnea [37], and the physicians thus attributed to
brucellosis a predominantly respiratory distress course
and the capacity for person-to-person transmission (more
worrying, though, was the fact that only 15% accurately
diagnosed pneumonic plague, which was the correct di-
agnosis). Although most imported cases in the developed,
brucellosis-free world can be accurately traced to travel
in, or importation of food from, endemic areas [38], this
relationship is not always evident. Even in endemic areas,
a minority of patients (14%) could not readily identify the
source of the infection [39]. A diagnosis of brucellosis in
a patient from a non-endemic area in the absence of spe-
cific risk factors for acquisition of the disease should lead
at least to enhanced awareness for the following days, in
order to readily identify an evolving trend and respond
adequately and rapidly.
Isolating the organism remains the gold diagnostic stan-
dard, although blood culture positivity is reported to vary
widely [40], and bone marrow aspiration and culture,
considered by some as extremely sensitive [41], remains
an invasive, painful procedure. Moreover, in the context
of an outbreak, the traditionally protracted period needed
for species culture and identification (ranging from 3
days to 6 weeks), means that other diagnostic procedures
should be sought.
Serology, in the form of various agglutination tests target-
ing surface antigens, and enzyme-linked immunosorbent
assay (ELISA), targeting other bacterial antigens [42],
is extremely useful; sensitivity and specificity are well
above 85% for both approaches. Drawbacks of serum ag-
glutination tests include false-negative results of varying
etiology (delayed seroconversion, blocking antibodies,
prozone phenomenon) and cross-reaction-induced false
positive results, and the inability to serologically follow
patients up due to protracted persistence of increased an-
tibody titers. ELISA is more sensitive, and a diagnostic
procedure of choice for cerebrospinal fluid specimens in
neurobrucellosis, but evolution of antibody titers in fol-
low-up and detection of relapses are still troublesome.
Various polymerase chain reaction (PCR) assays have
been developed but clinical studies are limited [43].
Cell. Mol. Life Sci. Multi-author Review Article 5
Moreover- real-time PCR (rtPCR) is now emerging as an
important diagnostic tool [44, 45]. Specific PCR assays
for field detection of significant bioterror pathogens have
also been developed by the military [46].
rtPCR may offer a rapid (less than an hour), exquisitely
sensitive and specific diagnosis in a deliberate release
outbreak, although traditional serology might be more
suitable as a diagnostic tool in such a situation: the trend
would be rapidly recognized. (Even when taking into ac-
count false negatives, the majority of patients will sero-
convert, and even in an endemic area, high titers could
not be attributed to previous contact with the pathogen.
On the other hand, false positives would be extremely un-
likely, and should be entertained only as a possible prob-
lem in a deliberate release of F. tularensis, where a false
positive diagnosis of brucellosis might steer response in
a wrong direction). Microorganism isolation for further
characterization and recognition of any genetic modifi-
cations would of course remain paramount in the overall
Various principles apply to brucellosis treatment: the or-
ganism hides inside macrophages which requires antibi-
otics with adequately intracellular penetration. Moreover,
these antibiotics need to be active in the acidic environ-
ment where the bacteria reside. The optimal treatment
is a combination regimen, since monotherapy has been
traditionally associated with an increased percentage of
treatment failure and relapse [46, 47]. Duration of treat-
ment also matters [48], and 6-week regimens are asso-
ciated with an acceptable percentage of relapses. The
World Health Organization (WHO) endorses regimens
that combine doxycycline, 100 mg b.i.d., and rifampicin,
600–1200 mg daily, for 6 weeks, or doxycycline for 6
weeks and streptomycin, 15 mg/kg daily, for 2–3 weeks.
The latter combination is considered superior [49], but
demands parenteral administration. Gentamicin can
adequately replace streptomycin, at a dose of 5 mg/kg
for 5–7 days. Alternatives include trimethoprim-sulfa-
methoxazole in various combinations, and combinations
including ofloxacin or ciprofloxacin. Quinolone-contain-
ing regimens are generally adequate, but cost-effective-
ness and the possibility of community resistance are is-
sues to be considered [50]. Triple or quadruple protracted
regimens should be used in serious complications, in con-
junction with invasive procedures, as indicated. Rifam-
picin and trimethoprim-sulfamethoxazole are the main-
stays of treatment in pregnancy and pediatric populations,
respectively. Future options may incorporate adjuvants
aiming at altering the acidic intracellular environment or
new antibiotics [51].
The development of a vaccine for brucellosis suitable for
humans would be an ideal solution to the problems of in-
adequate veterinary control of animal disease, inadequate
epidemiological study of human disease and inadequate
antibiotic treatment. The absence of such a vaccine un-
derlines the absence of interest in a common, albeit usu-
ally non-fatal, zoonosis, at least in areas with adequate
scientific and financial tools for such development and
the still incomplete knowledge about important steps of
the molecular pathogenesis of brucellosis.
Numerous vaccines have been tested in the past; none
of them have gained wide acceptance [52]. An intrader-
mally administered vaccine derived from B. abortus 19
strain has been used extensively in the Asian Republics
of the former Soviet Union, causing a 5–11 fold reduc-
tion in the annually reported cases of human brucellosis.
Still, the vaccine offers limited protection of short dura-
tion and requires booster doses. Moreover, an increased
number of hypersensitivity reactions were reported, with
76% local reactions and 3–7% generalized adverse ef-
fects [53].
Another vaccine used in the same area, similar to the
previous but administered intramuscularly, appeared
to evoke minimal reactions and similar protection. Its
reported efficacy after 75,000 doses performed in Ka-
zhakstan reached 79%. Strains of B. abortus 84-C and
104-M have been utilized for intradermal injection or
inhalation in the former Soviet Union and in China,
respectively [54]. The vaccines were considered effec-
tive but of high risk for serious adverse reactions. The
French experience with a vaccine utilizing a phenol-
insoluble peptidoglycan fraction of B. melitensis strain
M-15 raised questions in the past about its efficacy. The
vaccine was administered in two subcutaneous doses
and supposedly offered protection for a 2-year period
[55]. Efficacy of other vaccines that could be consid-
ered for humans has been proven in animals: the vari-
ous preparations include a lipopolysaccharide-protein
conjugate, a purified protein antigen L7/L12, Cu-Zn
SOD, and glyceraldehyde-dehydrogenase. Theoretical
vaccine targets for the future include the RB51 strain
(although it induces minimal human disease, which is
rifampicin resistant) [56], purE mutants (that still have
significant residual virulence), rfbK mutants of B. meli-
tensis, Omp 19, Omp 28, and the cytoplasmic protein
BP-26 [57].
Yet even if developed, the efficacy of a human vaccine in
the setting of a deliberate release outbreak would be mini-
mal. Sufficient prophylaxis in such a case would demand
pre-emptive vaccine administration, since following ex-
posure, and despite the prolonged incubation period of the
disease, antibody production would not be brisk enough.
Antibiotics would be the only option in such a case. The
use of antibiotic prophylaxis for asymptomatic persons
exposed to Brucella is an inadequately studied issue [58];
6 G. Pappas et al. Brucellosis and bioterrorism
most data derive from accidental laboratory exposure. In
general, the most prudent approach would be to follow
up for seroconversion, and subsequently treat, even when
no symptoms appear. With this strategy, prophylaxis ad-
ministration would be minimized, and persons at risk of
developing brucellosis (the ones seroconverting) would
be adequately treated. Another option would be to with-
hold antibiotics in the absence of any symptoms, even
for persons exhibiting seroconversion. But the insidious
course of the disease would leave these patients at risk
of developing brucellosis for practically the rest of their
Environmental implications
A deliberate release outbreak of brucellosis would obvi-
ously have profound environmental effects, their range
depending on characteristics of the targeted area. Areas
whose economy is largely based on animal productivity
would suffer the most, due to massive loss of livestock
and diminished trade in dairy products in the future.
Even though the overall financial burden of health ser-
vices would be lower than most other potential biological
weapons [59], the long-term effect on the targeted region’s
economy would be profound, more so when taking into
account environmental pollution, which has the potential
for secondary airborne community outbreaks.
Attack scenarios
The art of developing attack scenarios, and in that manner
outlining problems that might emerge in a real-life situa-
tion, has been inadequately explored. This is particularly
important since the same attack would have different out-
comes in different targeted areas, depending on numer-
ous characteristics. Even the public response would be
different, depending on awareness, and endemicity. A tra-
ditional attack scenario [60] projected minimal fatalities
in a Brucella attack under ‘optimal’ circumstances. Yet
when a similar scenario was transcribed in an endemic
area, the projected outcome was far less morbid [61].
In this latter scenario, an attack in an endemic city of
100,000 inhabitants would result in only two deaths, and
the level of social disruption would be minimal, due to
public awareness of the pathogen.
The importance of Brucella as a biological weapon may
only be historical nowadays, due to its minimal mortal-
ity and protracted inoculation period. Yet our times have
taught us that everything is possible. Educating physi-
cians and public alike, walking the fine line between in-
adequate awareness and fear of a ‘nasty bug’, might help
in limiting unnecessary interventions, in determining ar-
eas of research that need to be addressed, and in creating a
web of response that is adequate yet not overly restrictive
for scientists.
1 Centers for Disease Control and Prevention. Emergency
Preparedness and Response. Bioterrorism agents/diseases.
Accessed. June. 29, 2006, at
2 National Institute of Allergy and Infectious Diseases Biode-
fense Research. NIAID Biodefense Agenda for CDC Category
B and C Priority Pathogens. Accessed June 29, 2006, at http://
3 Pappas, G., Akritidis, N., Bosilkovski, M. and Tsianos, E.
(2005) Brucellosis. N. Engl. J. Med. 352, 2325–2336.
4 Sohn, A. H., Probert, W. S., Glaser, C. A., Gupta, N., Bollen,
A. W., Wong, J. D., Grace, E. M. and McDonald, W. C. (2003)
Human neurobrucellosis with intracerebral granuloma caused
by a marine mammal Brucella spp. Emerg. Infect. Dis. 9, 485–
5 DelVecchio, V. G., Kapatral, V., Redkar, R. J., Patra, G., Mujer,
C., Los, T., Ivanova, N., Anderson, I., Bhattacharyya, A., Lyki-
dis, A. et al. (2002) The genome sequence of the facultative
intracellular pathogen Brucella melitensis. Proc. Natl. Acad.
Sci. USA 99, 443–448.
6 Sanchez, D. O., Zandomeni, R. O., Cravero, S., Verdun,
R. E.,Pierrou, E., Faccio, P., Diaz, G., Lanzavecchia, S., Aguero,
F., Frasch, A. C. et al. (2001) Gene discovery through genomic
sequencing of Brucella abortus. Infect. Immun. 69, 865–868.
7 Paulsen, I. T., Seshadri, R., Nelson, K. E., Eisen, J. A., Heidel-
berg, J. F., Read, T. D., Dodson, R. J., Umayam, L., Brinkac,
L. M., Beanan, M. J. et al. (2002) The Brucella suis genome
reveals fundamental similarities between animal and plant
pathogens and symbionts. Proc. Natl. Acad. Sci. USA 99,
8 Michaux-Charachon, S., Jumas-Bilak, E., Allardet-Servent, A.,
Bourg, G., Boschiroli, M. L., Ramuz, M. and O’Callaghan, D.
(2002) The Brucella genome at the beginning of the post-ge-
nomic era. Vet. Microbiol. 90, 581–585.
9 Godfroid, J. and Kasbohrer, A. (2002) Brucellosis in the Euro-
pean Union and Norway at the turn of the twenty-first century.
Vet. Microbiol. 90, 135–145.
10 Pope, C. Feel safer now? Huffington Post. Accessed June 29,
2006, at
11 Capasso, L. (2002) Bacteria in two-millennia-old cheese, and
related epizoonoses in Roman populations. J. Infect. 45, 122–
12 Vassallo, D. J. (1992) The corps disease: brucellosis and its his-
torical association with the Royal Army Medical Corps. J. R.
Army Med. Corps 138, 140–150.
13 Christopher, G. W., Agan, M. B., Cieslak, T. J. and Olson, P. E.
(2005) History of U. S. military contributions to the study of
bacterial zoonoses. Mil. Med. 170, Suppl. 39–48.
14 Alibeck, K. (1999) Biohazard. Hutchinson, London.
15 Pappas, G., Papadimitriou, P., Akritidis, N., Christou, L. and
Tsianos, E. V. (2006) The new global map of human brucel-
losis. Lancet Infect. Dis. 6, 91–99.
16 Doyle, T. J. and Bryan, R. T. (2000) Infectious disease morbid-
ity in the US region bordering Mexico, 1990–1998. J. Infect.
Dis. 182, 1503–1510.
17 Center for Disease Control and Prevention (2000) Suspected
brucellosis case prompts investigation of possible bioterrorism-
related activity – New Hampshire and Massachusetts, 1999.
MMWR 49, 509–512.
Cell. Mol. Life Sci. Multi-author Review Article 7
18 Gorvel, J. P. and Moreno, E. (2002) Brucella intracellular life:
from invasion to intracellular replication. Vet. Microbiol. 90,
19 Yingst, S. and Hoover, D. L. (2003) T cell immunity to brucel-
losis. Crit. Rev. Microbiol. 29, 313–331.
20 Yagupsky, P. and Baron, E. J. (2005) Laboratory exposures to
brucellae and implications for bioterrorism. Emerg. Infect. Dis.
11, 1180–1185.
21 Pappas, G., Akritidis, N. and Tsianos, E. V. (2005) Attack sce-
narios with Rickettsial species. Implications for response and
management. Ann. N.Y. Acad. Sci 163, 451–458.
22 Casadevall, A. and Pirofski, L. A. (2004) The weapon potential
of a microbe. Trends Microbiol. 12, 259–263.
23 Colmenero, J. D., Reguera, J. M., Martos, F., Sanchez-De-
Mora, D., Delgado, M., Causse, M., Martin-Farfan, A. and
Juarez, C. (1996) Complications associated with Brucella meli-
tensis infection: a study of 530 cases. Medicine (Baltimore) 75,
195–211. Erratum in: (1997) Medicine (Baltimore) 76, 139.
24 Saltoglu, N., Tasova, Y., Midikli, D., Akhsu, H. S., Sanli, A. and
Dundar, I. H. (2004) Fever of unknown origin in Turkey: evalu-
ation of 87 cases during a nine-year-period of study. J. Infect.
48, 81–85.
25 Solera, J., Lozano, E., Martinez-Alfaro, E., Espinosa, A., Cas-
tillejos, M. L. and Abad, L. (1999) Brucellar spondylitis: re-
view of 35 cases and literature survey. Clin. Infect. Dis. 29,
26 Pappas, G., Seitaridis, S., Akritidis, N. and Tsianos, E. (2004)
Treatment of Brucella spondylitis: lessons from an impossible
meta-analysis and initial report of efficacy of a fluoroquino-
lone-containing regimen. Int. J. Antimicrob. Agents 24, 502–
27 Akritidis, N., Mastora, M. and Pappas, G. (2002) Genitourinary
complications of Brucellosis. Infect. Med. 19, 384–386.
28 Akritidis, N. and Pappas, G. (2001) Ascites caused by brucel-
losis: a report of two cases. Scand. J. Gastroenterol. 36, 110–
29 Shakir, R. A., Al-Din, A. S., Araj, G. F., Lulu, A. R., Mousa,
A. R. and Saadah, M. A. (1987) Clinical categories of neuro-
brucellosis. A report on 19 cases. Brain 110, 213–223.
30 Hadjinikolaou, L., Triposkiadis, F., Zairis, M., Chlapoutakis,
E. and Spyrou, P. (2001) Successful management of Brucella
mellitensis endocarditis with combined medical and surgical
approach. Eur. J. Cardiothorac. Surg. 19, 806–810.
31 Pappas, G., Bosilkovski, M., Akritidis, N., Mastora, M., Krteva,
L. and Tsianos, E. (2003) Brucellosis and the respiratory sys-
tem. Clin Infect. Dis 37, e95–e99.
32 Sevinc, A., Buyukberber, N., Camci, C., Buyukberber, S. and
Karsigil, T. (2005) Thrombocytopenia in brucellosis: case re-
port and literature review. J. Natl. Med. Assoc. 97, 290–293.
33 Khan, M. Y., Mah, M. W. and Memish, Z. A. (2001) Brucellosis
in pregnant women. Clin. Infect. Dis. 32, 1172–1177.
34 Lubani, M. M., Dudin, K. I., Sharda, D. C., Ndhar, D. S., Araj,
G. F., Hafez, H. A., al-Saleh, O. A., Helin, I. and Salhi, M. M.
(1989) A multicenter therapeutic study of 1100 children with
brucellosis. Pediatr. Infect. Dis. J. 8, 75–78.
35 Moreno, S., Ariza, J., Espinosa, F. J., Podzamczer, D., Miro,
J. M., Rivero, A., Rodriguez-Zapata, M., Arizzabalaga, J., Ma-
teos, R. and Herrero, F. (1998) Brucellosis in patients infected
with the human immunodeficiency virus. Eur. J. Clin. Micro-
biol. Infect. Dis. 17, 319–326.
36 Murrell, T. G. and Matthews, B. J.(1990) Multiple sclerosis
one manifestation of neurobrucellosis? Med. Hypotheses 33,
37 Cosgrove, S. E., Perl, T. M., Song, X. and Sisson, S. D. (2005)
Ability of physicians to diagnose and manage illness due to
category A bioterrorism agents. Arch. Intern. Med. 165, 2002–
38 Al Dahouk, S., Nockler, K., Hensel, A., Tomaso, H., Scholz,
H. C., Hagen, R. M. and Neubauer, H. (2005) Human brucel-
losis in a nonendemic country: a report from Germany, 2002
and 2003. Eur. J. Clin. Microbiol. Infect. Dis. 24, 450–456.
39 Pappas, G., Siozopoulou, V., Saplaoura, K., Vasiliou, A., Chris-
tou L, Akritidis, N. and Tsianos, E. V. (2006) Health literacy in
the field of infectious diseases: the paradigm of brucellosis. J.
Infect. Mar. 10 [Epub ahead of print].
40 Al Dahouk, S., Tomaso, H., Nockler, K., Neubauer, H. and
Frangoulidis, D. (2003) Laboratory-based diagnosis of brucel-
losis – a review of the literature. Part I: Techniques for direct
detection and identification of Brucella spp. Clin. Lab. 49,
41 Gotuzzo, E., Carrillo, C., Guerra, J. and Llosa, L. (1986) An
evaluation of diagnostic methods for brucellosis – the value of
bone marrow culture. J. Infect. Dis. 153, 122–125.
42 Al Dahouk, S., Tomaso, H., Nockler, K., Neubauer, H. and
Frangoulidis, D. (2003) Laboratory-based diagnosis of brucel-
losis – a review of the literature. Part II: serological tests for
brucellosis. Clin. Lab. 49, 577–589.
43 Navarro, E., Casao, M. A. and Solera, J. (2004) Diagnosis of
human brucellosis using PCR. Expert Rev. Mol. Diagn. 4, 115–
44 Queipo-Ortuno, M. I., Colmenero, J. D., Baeza, G. and Morata,
P. (2005) Comparison between LightCycler Real-Time Poly-
merase Chain Reaction (PCR) assay with serum and PCR-en-
zyme-linked immunosorbent assay with whole blood samples
for the diagnosis of human brucellosis. Clin. Infect. Dis. 40,
45 Vrioni, G., Priavali, E., Pappas, G., Gartzonika, C., Kostoula,
A., Boboyanni, H., Pappa, C., Stafanou D. and Levidiotou, S.
(2005) Real-time PCR assay for detection of Brucella DNA
in clinical samples from patients with suspected brucellosis. J.
Chemother. 17, Suppl. 26.
46 Pappas, G., Akritidis, N. and Tsianos, E. (2005) Effective treat-
ments in the management of brucellosis. Expert Opin. Pharma-
cother. 6, 201–209.
47 Solera, J., Martinez-Alfaro, E. and Espinoza, A. (1997) Recogni-
tion and optimum treatment of brucellosis. Drugs 53, 245–256.
48 Solera, J., Geijo, P., Largo, J., Rodriguez-Zapata, M., Gijon,
J., Martinez-Alfaro, E., Navarro, E., Macia, M. A. and Grupo
de Estudio de Castilla-la Mancha de Enfermedades Infecciosas
(2004) A randomized, double-blind study to assess the optimal
duration of doxycycline treatment for human brucellosis. Clin.
Infect. Dis. 39, 1776–1182.
49 Solera, J., Martinez-Alfaro, E. and Saez, L. (1994) [Meta-
analysis of the efficacy of the combination of rifampicin and
doxycycline in the treatment of human brucellosis.] Med. Clin.
102, 731–738.
50 Falagas, M. E. and Bliziotis, I. A. (2006) Quinolones for treat-
ment of human brucellosis: critical review of the evidence from
microbiological and clinical studies. Antimicrob. Agents Che-
mother. 50, 22–33.
51 Pappas, G., Solera, J., Akritidis, N. and Tsianos, E. V. (2005)
New approaches to the antibiotic treatment of brucellosis. Int.
J. Antimicrob. Agents 26, 101–105.
52 Schurig, G. G., Sriranganathan, N. and Corbel, M. J. (2002)
Brucellosis vaccines: past, present and future. Vet. Microbiol.
90, 479–496.
53 Young, E. J and Corbel, M. J. (1989) Brucellosis: Clinical and
Laboratory Aspects, CRC Press.
54 Deqiu, S., Donglou, X. and Jiming, Y. (2002) Epidemiology
and control of brucellosis in China. Vet. Microbiol. 90, 165–
55 Hadjichristodoulou, C., Voulgaris, P., Toulieres, L., Babalis, T.,
Manetas, S., Goutziana, G., Kastritis, I. and Tselentis, I. (1994)
Tolerance of the human brucellosis vaccine and the intradermal
reaction test for brucellosis. Eur. J. Clin. Microbiol. Infect. Dis.
13, 129–134.
56 Ashford, D. A., di Pietra J,. Lingappa, J., Woods, C., Noll, H.,
Neville, B., Weyant, R., Bragg, S. L., Spiegel, R. A., Tappero, J.
8 G. Pappas et al. Brucellosis and bioterrorism
and Perkins, B. A. (2004) Adverse events in humans associated
with accidental exposure to the livestock brucellosis vaccine
RB51. Vaccine 22, 3435–3439.
57 Ko, J. and Splitter, G. A. (2003) Molecular host-pathogen in-
teraction in brucellosis: current understanding and future ap-
proaches to vaccine development for mice and humans. Clin.
Microbiol. Rev. 16, 65–78.
58 Bossi, P., Tegnell, A., Baka, A., Van Loock, F., Hendriks, J.,
Werner, A., Gouvras G., Task Force on Biological and Chemi-
cal Agent Threats, Public Health Directorate, European Com-
mission, Luxembourg (2004) Bichat guidelines for the clinical
management of brucellosis and bioterrorism-related brucello-
sis. Euro Surveill. 9, E15–E16.
59 Kaufmann, A. F., Meltzer, M. I. and Schmid, G. P. (1997) The
economic impact of a bioterrorist attack: are prevention and
postattack intervention programs justifiable? Emerg. Infect.
Dis. 3, 83–94.
60 World Health Organization (1970) Health Aspects of Chemical
and Biological Weapons: Report of a WHO Group of Consul-
tants. World Health Organization, Geneva, Switzerland.
61 Pappas, G. and Akritidis, N. (2001) A scenario of bioterrorism
in the Balkans. Pharmacother 21, Suppl. 1, 47.
... The outbreak involved factory personnel and spread to neighboring communities, affecting >10,000 residents [1]. The event represents a tragic and tangible reminder of the high transmissibility of members of the genus and the potential role of brucellae as bioterrorism agents [2]. Although the Lanzhou outbreak stands out because of its enormous size, it should be pointed out that brucellosis is one of the most common organisms transmitted in the laboratory setting, and smaller LAB clusters have repeatedly occurred worldwide [3,4]. ...
... A prompt and clear-cut diagnosis of human brucellosis is critical for the patient's management because successful antibiotic therapy requires prolonged administration of drug combinations that are not employed for other infections, and unless the organism is eradicated at the early stages of the disease, brucellosis may run a chronic and complicated clinical course [11]. Furthermore, the diagnosis of brucellosis in humans has serious public health significance because it implies contact with a zoonotic source that has to be traced, identified, and controlled, or could represent a bioweapon attack [2,20]. ...
... The members of the laboratory personnel potentially involved in the exposure should be identified, and the individual risk should be assessed as high or low following the Centers for Diseases Control and Prevention guidelines [60], as condensed in Table 2. Because of the high infectivity of Brucella organisms, the attack rate of clinical disease among exposed laboratory personnel is remarkably high, and 71 LAB cases were diagnosed among 167 exposed workers summarized by Traxler et al. [2]. Therefore, post-exposure prophylaxis consisting of doxycycline (100 mg) orally twice daily and rifampin (600 mg) once daily for a minimum of 21 days should be offered to those considered to be at high risk for LAB and immunosuppressed individuals disregarding the risk level. ...
Full-text available
Brucellosis is one of the most common etiologies of laboratory-acquired infections worldwide, and handling of living brucellae should be performed in a Class II biological safety cabinet. The low infecting dose, multiple portals of entry to the body, the wide variety of potentially contaminated specimens, and the unspecific clinical manifestations of human infections facilitate the unintentional transmission of brucellae to laboratory personnel. Work accidents such as spillage of culture media cause only a small minority of exposures, whereas >80% of events result from unfamiliarity with the phenotypic features of the genus, misidentification of isolates, and unsafe laboratory practices such as working on an open bench without protective goggles or gloves or the aerosolization of bacteria. The bacteriological diagnosis of brucellae by traditional methods is simple and straightforward but requires extensive manipulation of the isolates, and, nowadays, many laboratory technicians are not familiar with the genotypic features of the genus, resulting in inadvertent exposure and contagion. Detection of brucellar infections by culture-independent molecular methods is safe, but the identification of the organism using MALDI-TOF technology is not hazard-free, requiring an initial bacterial inactivation step to avoid transmission. Unfortunately, these novel and safer methods are costly and frequently unavailable in resource-limited endemic countries.
... The zoonotic illness brucellosis is caused by the Brucella species, which are highly dangerous animal infections that cause significant economic losses in the livestock sector and widespread human morbidity. 1 Numerous terrestrial and aquatic mammals, including cows, buffaloes, sheep, goats, pigs, dogs, dolphins, whales, seals, and desert wood rats, are susceptible to the Gram-negative bacterium known as Brucella species. There are six well-known species of Brucella, which are B. abortus, which infects cattle, B. melitensis, which infects sheep and goats, B. suis, which infects pigs, B. ovis, which infects sheep, B. canis, which infects dogs, and B. neotomae, which infects wood desert rats. ...
This review discusses Brucella-host interactions on molecular base and brucellosis immunobiological response. Also, the review handles pathogenesis-informed rationales to prevent or treat brucellosis. Brucella species is an animal pathogen that may cause incidental human brucellosis as a zoonotic disease. Brucellosis results in worldwide economic losses, human morbidity, and poverty. Despite Brucella species infect humans as an incidental host, 500,000 new human brucellosis occur annually, and no approved human vaccines or patient-friendly therapies are available. Brucella has strong tissue tropism for lymphoreticular and reproductive systems with an intracellular lifestyle that hinders its exposure to innate and adaptive immune responses, sequesters the pathogen from antibiotics effect and drives clinical disease manifestations and pathology. Stealthy brucellae exploit strategies to establish infection, including i) evasion of intracellular destruction by restricting fusion of type IV secretion system(T4SS) dependent Brucella-containing vacuoles with lysosomal compartments, ii) inhibition of apoptosis of infected mononuclear cells, and iii) prevention of DC maturation, antigen presentation, and activation of naive T cells, pathogenesis lessons that may be informative for other intracellular pathogens. Data sets of NGS of Brucella and host time-series global expression fused with proteomics and metabolomics data from in vitro and in vivo experiments now approved human vaccines inform interactive cellular pathways and gene regulatory networks enabling full-scale systems biology analysis. The newly identified effector proteins of Brucella may represent novel targets for safer and more effective brucellosis vaccines and treatment.
... More common, non-lethal symptoms, such as arthritis and neurological symptoms, also contribute to the morbidity of humans suffering from chronic brucellosis (3). Additionally, given their small size, low infectious dose, and easy aerosolization, some Brucella species are considered potential agents of biological weaponry (4). ...
Full-text available
Brucella spp. are Gram-negative bacteria that naturally infect a variety of domesticated and wild animals, often resulting in abortions and sterility. Humans exposed to these animals or animal products can also develop debilitating, flu-like disease. The brucellae are intracellular pathogens that reside predominantly within immune cells, typically macrophages, where they replicate in a specialized compartment. This capacity of Brucella to survive and replicate within macrophages is essential to their ability to cause disease. In recent years, several groups have identified and characterized small regulatory RNAs (sRNAs) as critical factors in the control of Brucella physiology within macrophages and overall disease virulence. sRNAs are generally < 300 nucleotides in length, and these independent sRNA transcripts are encoded either next to (i.e., cis -encoded) or at a distant location to (i.e., trans -encoded) the genes that they regulate. Trans -encoded sRNAs interact with the mRNA transcripts through short stretches of imperfect base pairing that often require the RNA chaperone Hfq to facilitate sRNA-mRNA interaction. In many instances, these sRNA-mRNA interactions inhibit gene expression, usually by occluding the ribosome-binding site (RBS) and/or by decreasing the stability of the mRNA, leading to degradation of the transcript. A number of sRNAs have been predicted and authenticated in Brucella strains, and a variety of approaches, techniques, and means of validation have been employed in these efforts. Nonetheless, some important issues and considerations regarding the study of sRNA regulation in Brucella need to be addressed. For example, the lack of uniform sRNA nomenclature in Brucella has led to difficulty in comparisons of sRNAs across the different Brucella species, and there exist multiple names in the literature for what are functionally the same sRNA. Moreover, even though bona fide sRNAs have been discovered in Brucella , scant functional information is known about the regulatory activities of these sRNAs, or the extent to which these sRNAs are required for the intracellular life and/or host colonization by the brucellae. Therefore, this review summarizes the historical context of Hfq and sRNAs in Brucella ; our current understanding of Brucella sRNAs; and some future perspectives and considerations for the field of sRNA biology in the brucellae.
... The Brucella genus contains Gram-negative and intracellular bacteria [1,2] that are listed as category B bioterrorism agents [3], rendering them a considerable concern to human and environmental welfare. Animal and human brucellosis show similar pathological phenomena at the cellular level [4]. ...
Full-text available
The expression of flagellar proteins in Brucella species likely evolved through genetic transference from other microorganisms, and contributed to virulence, adaptability, and biofilm formation. Despite significant progress in defining the molecular mechanisms behind flagellar gene expression, the genetic program controlling biofilm formation remains unclear. The flagellar transcriptional factor (FtcR) is a master regulator of the flagellar system’s expression, and is critical for B. melitensis 16M’s flagellar biogenesis and virulence. Here, we demonstrate that FtcR mediates biofilm formation under hyperosmotic stress. Chromatin immunoprecipitation with next-generation sequencing for FtcR and RNA sequencing of ftcR-mutant and wild-type strains revealed a core set of FtcR target genes. We identified a novel FtcR-binding site in the promoter region of the osmotic-stress-response regulator gene betI, which is important for the survival of B. melitensis 16M under hyperosmotic stress. Strikingly, this site autoregulates its expression to benefit biofilm bacteria’s survival under hyperosmotic stress. Moreover, biofilm reduction in ftcR mutants is independent of the flagellar target gene fliF. Collectively, our study provides new insights into the extent and functionality of flagellar-related transcriptional networks in biofilm formation, and presents phenotypic and evolutionary adaptations that alter the regulation of B. melitensis 16M to confer increased tolerance to hyperosmotic stress.
Full-text available
Brucellosis is a disease of livestock that is commonly asymptomatic until an abortion occurs. Disease in humans results from contact of infected livestock or consumption of contaminated milk or meat. Brucella zoonosis is primarily caused by one of three species that infect livestock, Bacillus abortus in cattle, B. melitensis in goats and sheep, and B. suis in pigs. To aid in disease prophylaxis, livestock vaccines are available, but are only 70% effective; hence, improved vaccines are needed to mitigate disease, particularly in countries where disease remains pervasive. The absence of knowing which proteins confer complete protection limits development of subunit vaccines. Instead, efforts are focused on developing new and improved live, attenuated Brucella vaccines, since these mimic attributes of wild-type Brucella, and stimulate host immune, particularly T helper 1-type responses, required for protection. In considering their development, the new mutants must address Brucella’s defense mechanisms normally active to circumvent host immune detection. Vaccination approaches should also consider mode and route of delivery since disease transmission among livestock and humans is believed to occur via the naso-oropharyngeal tissues. By arming the host’s mucosal immune defenses with resident memory T cells (TRMs) and by expanding the sources of IFN-γ, brucellae dissemination from the site of infection to systemic tissues can be prevented. In this review, points of discussion focus on understanding the various immune mechanisms involved in disease progression and which immune players are important in fighting disease.
Full-text available
Brucella species are considered a significant cause of reproductive pathology in male and female animals. Importantly, Brucella melitensis can induce reproductive disease in humans. Reproductive pathogenesis and evaluation of newly developed countermeasures against brucellosis studies have traditionally utilized female animal models. However, any potential, new intervention for use in humans would need to be evaluated in both sexes. Therefore, animal models for male reproductive brucellosis are desperately needed to understand disease progression. Accordingly, we evaluated guinea pigs and mice using B. melitensis 16 M in an intratracheal model of inoculation at different stages of infection (peracute, acute, and chronic) with an emphasis on determining the effect to the male reproductive organs. Aerosol inoculation resulted in colonization of the reproductive organs (testicle, epididymis, prostate) in both species. Infection peaked during the peracute (1-week post-infection [p.i.]) and acute (2-weeks p.i.) stages of infection in the mouse in spleen, epididymis, prostate, and testicle, but colonization was poorly associated with inflammation. In the guinea pig, peak infection was during the acute stage (4-weeks p.i.) and resulted in inflammation that disrupted spermatogenesis chronically. To determine if vaccine efficacy could be evaluated using these models, males were vaccinated using subcutaneous injection with vaccine candidate 16 M ΔvjbR at 10 ⁹ CFU/100 μl followed by intratracheal challenge with 16 M at 10 ⁷ . Interestingly, vaccination efficacy varied between species and reproductive organs demonstrating the value of evaluating vaccine candidates in multiple models and sexes. Vaccination resulted in a significant reduction in colonization in the mouse, but this could not be correlated with a decrease in inflammation. Due to the ability to evaluate for both colonization and inflammation, guinea pigs seemed the better model not only for assessing host-pathogen interactions but also for future vaccine development efforts.
Full-text available
Brucellosis poses a significant burden to human and animal health worldwide. Robust and harmonized molecular epidemiological approaches and population studies that include routine disease screening are needed to efficiently track the origin and spread of Brucella strains.
Full-text available
Brucellosis is a world-wide re-emerging zoonosis and the most frequent laboratory-acquired bacterial infection, causing severe disease in humans with unspecific clinical signs affecting numerous organs. Contact with infected animals, ingestion of contaminated animal products and handling of Brucella isolates in laboratories are risk factors. Various other febrile illnesses, e.g. malaria, tuberculosis, typhoid fever and tularemia may present with the same symptoms. Therefore, clinical diagnosis is difficult to establish but effective therapy requires an early diagnosis. Vaccines for humans are still not commercially available. Blood culturing of Brucella is time-consuming and not reliable. Thus diagnosis is usually based on indirect serological tests, i.e. serum agglutination test, complement fixation or the Coombs test. However, these 'conventional' serological tests lack sensitivity and specificity. Hence, a combination of various tests is mandatory for a definite diagnosis. Enzyme-linked immunosorbent assays can be used for screening and confirmation of brucellosis in one step. Molecular techniques like the polymerase chain reaction and restriction fragment length polymorphism are needed to differentiate species and strains within the genus Brucella. This review will summarize advantages and disadvantages of the techniques used in clinical laboratories for direct detection and identification of Brucella spp.
Full-text available
Brucellosis (also known as Malta, Mediterranean or Undulant Fever) has aptly been nicknamed the Corps Disease because of the major role played by the Royal Army Medical Corps in elucidating its nature and discovering its mode of spread, thus leading to its prevention and eradication. This history of brucellosis, incorporating a complete bibliography of all references to the disease in the Journal of the Royal Army Medical Corps from 1903 to 1992, documents the fascinating story of this association.
Brucella is still highly endemic in developing countries. Genitourinary (GU) complications of brucellosis occur in a small number of patients and take the form of orchiepididymitis, dysuria, hematuria or, rarely, pyelonephritis. We investigated GU complications in 60 consecutive patients admitted to a hospital in Greece with a diagnosis of brucellosis based on a serum agglutinin titer opf 1:320 or higher. Sixteen patients presented with various forms of GU complications. All patients were successfully treated with tetracycline and streptomycin.
A collection of chapters on various aspects of brucellosis including history, epidemiology, diagnosis and treatment by international authorities.
Brucellosis is a zoonosis still endemic in developing areas of the world. Focal complications of Brucellosis are well known and often troubling in the differential diagnosis. Gastrointestinal complications of Brucellosis are randomly reported, ascites being particularly rare, and usually in the context of a predisposing condition such as cirrhosis. We describe two cases of ascites attributed to Brucellosis, one in a previously healthy patient with an accompanying clinical picture of acute Brucellosis, in whom ascites reflected the response of the peritoneal mononuclear phagocytic system, and one in a HBsAg-positive, but not cirrhotic, patient, in whom Brucellosis seemed to act as a trigger effect for the development of ascites. Both cases of ascites were of an effusion type, with a predominantly lymphocytic cell count, and exhibited an excellent response to treatment with tetracycline and rifampicin.
— Twelve cases of genito-urinary complications of brucellosis are presented. Ten patients had epididymo-orchitis, 1 presented with right hydronephrosis and 1 with haematuria and dysuria. The 10 cases of epididymo-orchitis were compared with 15 cases of acute non-specific epididymo-orchitis. The former were of longer duration and were not associated with lower urinary tract symptoms; almost all of these patients had ingested unpasteurised milk. Non-specific epididymo-orchitis had a more acute onset, shorter duration and was associated more frequently with pyuria, lower urinary tract symptoms, higher leucocyte counts and insignificant brucella titres.The distinction between these two types of epididymo-orchitis is essential, since the treatments are entirely different.
There is good geographic evidence that an environmental factor is implicated in the aetiology of multiple sclerosis (MS). Controversy surrounds the interpretation of many studies supporting notions on whether the disease has greater prevalence in urban or rural communities. Rather than focus on residence at birth, in teenage years or at the time of study, analyses of MS mortality by occupation and a case control study to define exposure to animal farm products is thought to shed light in this controversy. The conclusion reached from the results of these studies is that exposure to farm animals or raw products is a common denominator in the aetiology of MS. A literature search for references of zoonotic disease with neurological symptoms produced a range of papers on brucellosis. A study of the literature on neurobrucellosis supports the hypothesis on clinical grounds. Finally, blood serum studies of Brucella exposure in a series of MS subjects and controls is described. These epidemiological studies support the hypothesis, that central nervous system involvement from exposure to brucellosis, may present with the features of multiple sclerosis.
A 6-year multicenter therapeutic study was performed on 1100 children with brucellosis in order to compare several antibiotic combinations and duration of treatment. The patients were randomized to receive oral therapy with oxytetracycline, doxycycline, rifampin and trimethoprim-sulfamethoxazole (TMP/SMX) either alone or in combination with each other or combined with streptomycin or gentamicin injections. The patients were also randomized into three groups based on the duration of oral therapy: 500 patients were treated for 3 weeks; 350 for 5 weeks; and 250 for 8 weeks. When intramuscular aminoglycosides were used, streptomycin was given for 2 weeks and gentamicin for 5 days. In oral monotherapy oxytetracycline, doxycycline and rifampin showed comparable results with low relapse rates (less than or equal to 9%) and no statistically significant differences were found among 3-, 5- or 8-week durations of therapy. TMP/SMX alone showed an unacceptably high relapse rate (30%) with all durations of therapy. In combined oral therapy rifampin plus oxytetracycline, rifampin plus TMP/SMX and oxytetracycline plus TMP/SMX showed comparable results with low relapse rates ranging from 4 to 8% in patients receiving therapy for 3 or 5 weeks, no relapses occurred in patients treated for 8 weeks. When oral monotherapy was combined with either streptomycin or gentamicin, very few relapses were seen, irrespective of the duration of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Brucellosis rarely can present with involvement restricted to the nervous system. We describe a total of 19 cases of neurobrucellosis in whom the clinical presentation lay in three distinct categories. The first was an acute presentation with meningoencephalitis. The disease also presented in a chronic form where the brunt of the illness can either be in the peripheral or the central nervous system (CNS). The chronic peripheral form is that of a proximal polyradiculoneuropathy. The central form is that of diffuse CNS involvement, predominantly with myelitis or cerebellar involvement with or without cranial nerve palsies. Although the two chronic forms, 'peripheral' and 'central', are distinct, some overlap is possible. This was not observed for the acute form. The pathology of the three presentations may be different, being a direct effect of infection in the acute form, and an immune-related process, possibly demyelinating in nature, in the chronic forms. The response to treatment in the acute and chronic forms is also different, being much better in the acute form. Awareness of the condition and performance of the appropriate serological tests will differentiate neurobrucellosis from other chronic CNS infections, especially tuberculosis and neurosyphilis.