You're the Flight Surgeon

Warneke J, Pavelites J. You're the flight surgeon: tularemia. Aerosp Med Hum Perform. 2020; 91(5):379-381.

Paediatric oropharyngeal tularaemia requiring surgical intervention

Tularaemia is a rare infectious disease endemic in most European countries caused by the bacterium Francisella tularensis 1 Patients often show acute non-specific symptoms, which causes a delay in diagnosis and proper treatment, potentially resulting in significant morbidities such as deep neck abscess, meningitis, endocarditis and septic shock. The authors present a case of a 5-year old boy with a 4-day history of fever, sore throat and painful cervical lymphadenopathy, whose clinical progression worsened despite being treated with recommended antibiotics as per WHO guidelines once the diagnosis of Tularaemia was confirmed by serologic tests. He developed a parapharyngeal abscess and a persistent left necrotic cervical lymph node, which both were surgically drained and excised, respectively, and an extended course of antibiotic was given. Subsequently, the patient fully recovered from the illness and the follow-up was negative for relapse.

Human Dose-Response Data for Francisella tularensis and a Dose- and Time-Dependent Mathematical Model of Early-Phase Fever Associated with Tularemia After Inhalation Exposure

Military health risk assessors, medical planners, operational planners, and defense system developers require knowledge of human responses to doses of biothreat agents to support force health protection and chemical, biological, radiological, nuclear (CBRN) defense missions. This article reviews extensive data from 118 human volunteers administered aerosols of the bacterial agent Francisella tularensis, strain Schu S4, which causes tularemia. The data set includes incidence of early-phase febrile illness following administration of well-characterized inhaled doses of F. tularensis. Supplemental data on human body temperature profiles over time available from de-identified case reports is also presented. A unified, logically consistent model of early-phase febrile illness is described as a lognormal dose-response function for febrile illness linked with a stochastic time profile of fever. Three parameters are estimated from the human data to describe the time profile: incubation period or onset time for fever; rise time of fever; and near-maximum body temperature. Inhaled dose-dependence and variability are characterized for each of the three parameters. These parameters enable a stochastic model for the response of an exposed population through incorporation of individual-by-individual variability by drawing random samples from the statistical distributions of these three parameters for each individual. This model provides risk assessors and medical decisionmakers reliable representations of the predicted health impacts of early-phase febrile illness for as long as one week after aerosol exposures of human populations to F. tularensis.

Epidemiological and clinical characteristics and management of oropharyngeal tularemia outbreak

BACKGROUND/AIM

The purpose of this study was to determine the epidemiological and clinical characteristics of patients diagnosed with tularemia and the effectiveness of the administered treatments.

MATERIALS AND METHODS

Patients treated in our hospital between January 2009 and March 2011 and diagnosed with tularemia were evaluated retrospectively. Patients' epidemiological and clinical characteristics, administered treatments, and posttreatment findings were recorded on patient monitoring forms.

RESULTS

At anamnesis, 29% of patients used water from wells and 71% used water from the network supply; moreover, 48.4% had a history of contact with animals and 87.1% a history of lethargy. At physical examination, 96.8% had a mass in the neck and 90.3% had fever. Gentamycin + doxycycline therapy was administered to 45.2% of patients, while levofloxacin, gentamycin, and streptomycin were used for the other patients. After treatment, neck masses persisted in 48.4% of patients and complaints of lethargy and fever in 6.5%. Treatment of these patients was initiated once tularemia had been diagnosed, as test results were announced about 3 weeks later. Lymphadenopathy excision was performed on 19.4% of patients in whom neck mass persisted.

CONCLUSION

Appropriate empiric antibiotherapy should be commenced in patients presenting with neck mass, fever, and lethargy in regions with tularemia epidemics.

[Epizootic and epidemic manifestation of natural foci of tularemia in Moscow region (1965-2013)]

AIM

Detection of contemporary features of tularemia focimanifestations, determination of territories of high epidemic risk in various landscape zones and creation of a map of foci territories of Moscow Region for isolation of tularemia infectious agent cultures and registered human morbidity for justified planning of prophylaxis measures.

MATERIALS AND METHODS

Report materials of epizootologic examinations of natural foci for 1965-2013, 156 maps of epidemiologic examination of cases of human infection with tularemia, results of studies of casting of predatory birds and dung of predatory mammals were used. Registered morbidity and isolation of tularemia infectious agent cultures from 1965 to date were applied to an electronic map of Moscow Region by sign method using modern. GIS-technologies (MapInfo 10.5 program). Electronic maps Ingit at 1:200,000 scale, as well as Google Earth program were used to search for base points.

RESULTS

Analysis of morbidity has revealed structure change in human tularemia morbidity--an increase of the fraction of urban population and a decrease of the fraction of patients among rural inhabitants, unimmunized against this infection are mostly ill. The presence of DNA of tularemia causative agent in biological objects in the complex with serologic and bacteriological studies was shown to allow to detect flaccid epizootics even at low numbers of rodents.

CONCLUSION

Cartographic reflection of registered morbidity and isolation of tularemia infectious agent cultures allowed to show territories with various degrees of epizootic activity and epidemic manifestation. Positive results of serologic and molecular-genetic studies of environmental objects gives evident on epizootic activity and constant risk of aggravation of epidemic situation for this infection.

Prospective investigation of the hypothalamo-pituitary-adrenal axis in patients with tularemia

BACKGROUND/AIM

To investigate prospectively the hypothalamo-pituitary-adrenal (HPA) axis by adrenocorticotropic hormone (ACTH) stimulation test.

MATERIALS AND METHODS

Tularemia was diagnosed according to guidelines. An ACTH stimulation test (1 µg) and a dexamethasone suppression test (DST; 1 mg) were performed in patients in the acute phase of tularemia before antibiotic treatment and in the chronic phase.

RESULTS

Nineteen patients (mean age: 41.0 ± 13.2 years; 57.9% female) with tularemia were enrolled in the study in 2011 and 2012. Cortisol response to ACTH stimulation test was sufficient in all patients during the acute phase. After the DST, the cortisol was not suppressed during the acute phase in only one patient. The median control time of 11 patients after acute tularemia was 13 months. During the chronic phase, cortisol response to ACTH stimulation was normal in all patients, and after DST cortisol was suppressed in all patients. The peak cortisol level after the ACTH stimulation test in the acute phase was higher than that in the chronic phase, but the difference was not statistically significant.

CONCLUSION

The HPA axis of patients with tularemia was not significantly affected in the acute and chronic phases.

Mouse models of aerosol-acquired tularemia caused by Francisella tularensis types A and B

After preliminary assessment of virulence in AKR/J, DBA/1, BALB/c, and C57BL/6 mice, we investigated histopathologic changes in BALB/c and C57BL/6 mice infected with type A (strain SCHU S4) or type B (strain 425) Francisella tularensis by aerosol exposure. In mice exposed to type A infection, changes in histologic presentation were not apparent until day 3 after infection, when pyogranulomatous inflammation was detected in spleens and livers of BALB/c mice, and in lungs and spleens of C57BL/6 mice. Histopathologic changes were most severe and widespread in both mouse strains on day 5 after infection and seemed to completely resolve within 22 d of challenge. BALB/c mice were more resistant than C57BL/6 mice in lethal-dose calculations, but C57BL/6 mice cleared the infection more rapidly. Mice similarly challenged with type B F. tularensis also developed histopathologic signs of infection beginning on day 3. The most severe changes were noted on day 8 and were characterized by granulomatous or pyogranulomatous infiltrations of the lungs. Unlike type A infection, lesions due to type B did not resolve over time and remained 3 wk after infection. In type B, but not type A, infection we noted extensive inflammation of the heart muscle. Although no microorganisms were found in tissues of type A survivors beyond 9 d after infection, mice surviving strain 425 infection had a low level of residual infection at 3 wk after challenge. The histopathologic presentation of tularemia caused by F. tularensis types A and B in BALB/c and C57BL/6 mice bears distinct similarities to tularemia in humans.

A method for functional trans-complementation of intracellular Francisella tularensis

Francisella tularensis is a highly infectious bacterial pathogen that invades and replicates within numerous host cell types. After uptake, F. tularensis bacteria escape the phagosome, replicate within the cytosol, and suppress cytokine responses. However, the mechanisms employed by F. tularensis to thrive within host cells are mostly unknown. Potential F. tularensis mutants involved in host-pathogen interactions are typically discovered by negative selection screens for intracellular replication or virulence. Mutants that fulfill these criteria fall into two categories: mutants with intrinsic intracellular growth defects and mutants that fail to modify detrimental host cell processes. It is often difficult and time consuming to discriminate between these two possibilities. We devised a method to functionally trans-complement and thus identify mutants that fail to modify the host response. In this assay, host cells are consistently and reproducibly infected with two different F. tularensis strains by physically tethering the bacteria to antibody-coated beads. To examine the efficacy of this protocol, we tested phagosomal escape, cytokine suppression, and intracellular replication for F. tularensis ΔripA and ΔpdpC. ΔripA has an intracellular growth defect that is likely due to an intrinsic defect and fails to suppress IL-1β secretion. In the co-infection model, ΔripA was unable to replicate in the host cell when wild-type bacteria infected the same cell, but cytokine suppression was rescued. Therefore, ΔripA intracellular growth is due to an intrinsic bacterial defect while cytokine secretion results from a failed host-pathogen interaction. Likewise, ΔpdpC is deficient for phagosomal escape, intracellular survival and suppression of IL-1β secretion. Wild-type bacteria that entered through the same phagosome as ΔpdpC rescued all of these phenotypes, indicating that ΔpdpC failed to properly manipulate the host. In summary, functional trans-complementation using bead-bound bacteria co-infections is a method to rapidly identify mutants that fail to modify a host response. Francisella tularensis is a facultative intracellular bacterial pathogen and is the causative agent of the disease tularemia. F. tularensis enters host cells through phagocytosis, escapes the phagosome, and replicates in the host cell cytosol while suppressing cytokine secretion [1]–[4]. Although substantial progress has been made in understanding the intracellular life cycle of F. tularensis, the F. tularensis proteins responsible for manipulating many host cell pathways are unknown. Identifying novel host-pathogen effector proteins is difficult because there is no rapid method to reliably distinguish between bacterial proteins that modify host processes and proteins that are involved in bacterial processes that are required for the bacteria to survive or replicate in the intracellular environment. The ability to identify mutants that are deficient for host-pathogen interactions is important because it can aid in prioritizing the investigation of genes of interest and in downstream experimental design. Moreover, certain mutant phenotypes, such as decreased phagosomal escape, hinder investigation of other potential phenotypes. A method to specifically complement these phenotypes would allow for further characterizations of certain F. tularensis mutants. Thus we sought to develop a method to easily identify and functionally complement mutants that are deficient for interactions with the host.

Galectin-3 functions as an alarmin: pathogenic role for sepsis development in murine respiratory tularemia

Sepsis is a complex immune disorder with a mortality rate of 20–50% and currently has no therapeutic interventions. It is thus critical to identify and characterize molecules/factors responsible for its development. We have recently shown that pulmonary infection with Francisella results in sepsis development. As extensive cell death is a prominent feature of sepsis, we hypothesized that host endogenous molecules called alarmins released from dead or dying host cells cause a hyperinflammatory response culminating in sepsis development. In the current study we investigated the role of galectin-3, a mammalian β-galactoside binding lectin, as an alarmin in sepsis development during F. novicida infection. We observed an upregulated expression and extracellular release of galectin-3 in the lungs of mice undergoing lethal pulmonary infection with virulent strain of F. novicida but not in those infected with a non-lethal, attenuated strain of the bacteria. In comparison with their wild-type C57Bl/6 counterparts, F. novicida infected galectin-3 deficient (galectin-3^−/−) mice demonstrated significantly reduced leukocyte infiltration, particularly neutrophils in their lungs. They also exhibited a marked decrease in inflammatory cytokines, vascular injury markers, and neutrophil-associated inflammatory mediators. Concomitantly, in-vitro pre-treatment of primary neutrophils and macrophages with recombinant galectin-3 augmented F. novicida-induced activation of these cells. Correlating with the reduced inflammatory response, F. novicida infected galectin-3^−/− mice exhibited improved lung architecture with reduced cell death and improved survival over wild-type mice, despite similar bacterial burden. Collectively, these findings suggest that galectin-3 functions as an alarmin by augmenting the inflammatory response in sepsis development during pulmonary F. novicida infection.

Use of temperature for standardizing the progression of Francisella tularensis in mice

The study of infectious agents, their pathogenesis, the host response and the evaluation of newly developed countermeasures often requires the use of a living system. Murine models are frequently used to undertake such investigations with the caveat that non-biased measurements to assess the progression of infection are underutilized. Instead, murine models predominantly rely on symptomology exhibited by the animal to evaluate the state of the animal's health and to determine when euthanasia should be performed. In this study, we used subcutaneous temperature as a non-subjective measurement to follow and compare infection in mice inoculated with Francisella tularensis, a Gram-negative pathogen that produces an acute and fatal illness in mice. A reproducible temperature pattern defined by three temperature phases (normal, febrile and hypothermic) was identified in all mice infected with F. tularensis, regardless of the infecting strain. More importantly and for the first time a non-subjective, ethical, and easily determined surrogate endpoint for death based on a temperature, termed drop point, was identified and validated with statistical models. In comparative survival curve analyses for F. tularensis strains with differing virulence, the drop point temperature yielded the same results as those obtained using observed time to death. Incorporation of temperature measurements to evaluate F. tularensis was standardized based on statistical models to provide a new level of robustness for comparative analyses in mice. These findings should be generally applicable to other pathogens that produce acute febrile disease in animal models and offers an important tool for understanding and following the infection process.

Tularaemia in Berlin - two independent cases in travellers returning from central Anatolia, Turkey, February 2011

Tularaemia, though rare, has recently been increasingly reported in Germany. Most cases are indigenous infections. This report describes two epidemiologically independent infections with Francisella tularensis subspecies holarctica detected in Berlin in February 2011 that were acquired in central Anatolia, Turkey. In Turkey, there have been repeated tularaemia outbreaks since 2000 and the disease should therefore be considered as a differential diagnosis in travellers returning from that country.

Tularaemia in an emergent area in Sweden: an analysis of 234 cases in five years

A retrospective study of clinical tularaemia in an emergent area in Sweden is presented. 234 patients seen during the y 2000-2004 were studied, using case files and a questionnaire. There was a predominance of ulceroglandular tularaemia (89%), occurring in late summer and early autumn, reflecting the dominance of mosquito-borne transmission. The incubation period varied from a few hours to 11 d, with a median of 3 d. Cutaneous manifestations of tularaemia, apart from primary lesions, were noted in 43% of the cases. Coughing was common, even in patients with ulceroglandular tularaemia, supporting the view that haematogenous spread to the respiratory system occurs. Regular laboratory tests, such as WBC, ESR and C-reactive protein, were in general only moderately elevated. In the earlier y studied, the Doctor's Delay was substantial as was the misdiagnosis and prescription of inadequate antibiotics. In the later y, however, the delay and misdiagnosis were significantly lower, reflecting the increased recognition of the disease by the physicians in the area. A few relapses occurred, all in patients treated with doxycycline. No lethality was seen, reflecting the benign course of tularaemia type B infection.

New approaches to diagnosis and therapy of tularemia

Francisella tularensis is a potent pathogen and a cause of severe human disease. The outcome of tularemia will depend on rapid insertion of appropriate antibiotics. Until recently, effective clinical handling was hampered by shortcomings in laboratory diagnostics. No suitable direct methods were available and, because of risks and isolate recovery difficulties associated with laboratory work, culture has been rarely practiced. Due to achievements from work on modern technology, however, tularemia can now be rapidly and specifically diagnosed. Conventional PCR has been successfully applied on wound specimens of patients acquiring tularemia, and prospects for application on other human specimens are promising. Besides allowing diagnostics at high sensitivity and specificity, the PCR technology will also facilitate the identification of cases of tularemia presenting with aberrant signs and symptoms. Antibiotics for efficacious treatment of tularemia have been available for several decades. Although highly valuable, these drugs are afflicted with adverse effects and/or are available only for parenteral therapy. Recently, quinolones have been shown to afford a new valuable option for treatment of tularemia caused by F. tularensis subsp. holarctica (type B). Experience in treating more severe disease caused by F. tularensis subsp. tularensis (type A) is currently limited. In essence, the clinical handling of tularemia is currently facilitated by new achievements in molecular diagnostics and, at least with regard to type B tularemia, by the introduction of quinolones for therapy.

Pneumonic tularemia on Martha's Vineyard: clinical, epidemiologic, and ecological characteristics

Martha's Vineyard, Massachusetts, is the site of the only two recognized outbreaks of primary pneumonic tularemia in the United States. Beginning in 2000 and continuing through 2006, 59 presumed or confirmed tularemia cases have been reported from Martha's Vineyard, with more than 60% of these presumed to be due to inhalation of the agent. A joint CDC/Massachusetts Department of Public Health case-control study identified landscaping activities such as lawnmowing or brush cutting to be important risk factors. The fomites that serve as the basis for risk for landscapers, however, remain unidentified. Clinically, cases generally have a pneumonic component, but the development of pulmonary signs can be greatly delayed. The spectrum of illness ranges from relatively mild disease, in which cases may be treated on an outpatient basis, to severe illness requiring hospitalization. In each scenario, gentamicin therapy tends to rapidly induce defervescence, although exceptions have been noted. Even with heightened awareness during the current outbreak, physicians may easily miss a diagnosis of tularemia, usually by attributing illness to the more common Febrile illnesses. Dog ticks appear to maintain the agent on this island, with as many as 5% infected by the agent of tularemia. The main hosts for dog ticks, skunks and raccoons, are very frequently seroreactive, suggesting the possibility for their involvement in environmental contamination due to their peridomestic habits. Why tularemia is prevalent on Martha's Vineyard and why it commonly presents as a pneumonic disease there remain undescribed.

Tularemia: History, Epidemiology, Pathogen Physiology, and Clinical Manifestations

Francisella tularensis has been recognized as a human pathogen for almost 100 years and is the etiological agent of the zoonotic disease tularemia. Soon after its discovery, it became recognized as an important pathogen in several parts of the world, for example, in the United States and Soviet Union. The number of tularemia cases in the two countries peaked in the 1940s and has thereafter steadily declined. Despite this decline, there was still much interest in the pathogen in the 1950s and 1960s since it is highly infectious and transmissible by aerosol, rendering it a potent biothreat agent. In fact, it was one of the agents that was given the highest priority in the offensive programs of the United States and Soviet Union. After termination of the offensive programs in the 1960s, the interest in F. tularensis diminished significantly and little research was carried out for several decades. Outbreaks of tularemia during the last decade in Europe, for example, in Kosovo, Spain, and Scandinavia, led to a renewed public interest in the disease. This, together with a massive increase in the research funding, in particular in the United States since 2001, has resulted in a significant increase in the number of active Francisella researchers. This article summarizes, predominantly with a historical perspective, the epidemiology and clinical manifestations of tularemia and the physiology of F. tularensis.

Mucosal Immunopathogenesis of Francisella tularensis

Respiratory infection with Francisella tularensis is the deadliest form of disease and represents the most likely route to be used by bioterrorists. Although mucosal surfaces represent the first line of defense against respiratory tularemia, and in fact, against the great majority of human pathogens, little is known about protective immunity at these sites. The objective of this chapter is to review recent data examining the importance of various pulmonary immune mechanisms in defense against F. tularensis infection and to evaluate potential strategies for induction of protective lung immunity. Aerosol and intranasal mouse infection models have yielded essentially equivalent results and have implicated an important role for Th1-type immune responses in protection, including IFN-gamma, TNF-alpha, and IL-12. The cells responsible for protection in the lung are not well-characterized but NK cells are an early target for activation after infection although it appears that CD8 T cells might be most critical for host resistance. In addition, it is becoming increasingly clear that antibodies can provide prophylactic and therapeutic protection against pulmonary infection but only in the presence of active cell-mediated immunity. In fact, in vitro exposure of resting macrophages to antibody-coated bacteria in the absence of IFN-gamma can actually enhance infection. Although various immune mechanisms can be shown to be important for protection against attenuated strains such as LVS, the real challenge for the future is to design efficacious approaches to prevent disease by highly virulent strains such as SchuS4.

Tick-borne infections in children: epidemiology, clinical manifestations, and optimal management strategies

Ticks can transmit bacterial, protozoal, and viral infections to humans. Specific therapy is available for several of these infections. Doxycycline is the antimicrobial treatment of choice for all patients, regardless of age, with Rocky Mountain spotted fever, human monocytic ehrlichiosis, or human granulocytic ehrlichiosis. Chloramphenicol has been used to treat these infections in children but is demonstrably inferior to doxycycline. In patients with Mediterranean spotted fever, doxycycline, chloramphenicol, and newer macrolides all appear to be effective therapies. Therapy of Lyme disease depends on the age of the child and stage of the disease. For early localized disease, amoxicillin (for those aged <8 years) or doxycycline (for those aged >/=8 years) is effective. Doxycycline, penicillin V (phenoxymethylpenicillin) or penicillin G (benzylpenicillin) preparations, and erythromycin are all effective treatments for tick-borne relapsing fever. Hospitalized patients with tularemia should receive gentamicin or streptomycin. Doxycycline and ciprofloxacin have each been investigated for the treatment of tularemia in outpatients; however, these agents do not yet have established roles in the treatment of this disease in children. Combination therapy with clindamycin and quinine is preferred for children with babesiosis; the combination of azithromycin and atovaquone also appears promising. Ribavirin has been recently shown to markedly improve survival in patients with Crimean-Congo hemorrhagic fever. The role of antiviral therapy in the treatment of other tick-borne viral infections, including other hemorrhagic fevers and tick-borne encephalitis, is not yet defined.

Laboratory analysis of tularemia in wild-trapped, commercially traded prairie dogs, Texas, 2002

Oropharyngeal tularemia was identified as the cause of a die-off in captured wild prairie dogs at a commercial exotic animal facility in Texas. From this point source, Francisella tularensis-infected prairie dogs were traced to animals distributed to the Czech Republic and to a Texas pet shop. F. tularensis culture isolates were recovered tissue specimens from 63 prairie dogs, including one each from the secondary distribution sites. Molecular and biochemical subtyping indicated that all isolates were F. tularensis subsp. holarctica (Type B). Microagglutination assays detected antibodies against F. tularensis, with titers as great as 1:4,096 in some live animals. All seropositive animals remained culture positive, suggesting that prairie dogs may act as chronic carriers of F. tularensis. These findings demonstrate the need for additional studies of tularemia in prairie dogs, given the seriousness of the resulting disease, the fact that prairie dogs are sold commercially as pets, and the risk for pet-to-human transmission.

Molecular diagnostic techniques for use in response to bioterrorism

The use of micro-organisms as agents of biological warfare is considered inevitable for several reasons, including ease of production and dispersion, delayed onset of symptoms, ability to cause high rates of morbidity and mortality and difficulty in diagnosis. Therefore, the clinical presentation and pathogenesis of the organisms posing the highest threat (variola major, Bacillus anthracis, Yersinia pestis, Clostridium botulinum toxin, Francisella tularensis, filoviruses, arenaviruses and Brucella species), as well as the available diagnostic techniques and treatments for such infections, will be reviewed in this article. Due to the necessity of rapid identification and diagnosis, molecular techniques have been the ongoing focus of current research. Consequently, the molecular diagnostic techniques that have recently been developed for the diseases associated with these agents will be emphasized.

Bioterrorism. Clinical recognition and primary management

The recent anthrax attacks in the United States have demonstrated the reality of bioterrorist threats as well as the need for preparedness and planning to mount a successful response to such events. Medical practitioners have a key role in responding to bioterrorist activity because they can contribute to the timely recognition of an event and to the mitigation of morbidity resulting from a bioterrorist attack. The medical community needs to become familiar with how to recognize and manage diseases produced by the biologic agents that might be used by terrorists. This review summarizes the microbiological and clinical aspects of the agents of anthrax, smallpox, plague, and tularemia, which are all considered likely bioterrorist weapons.

Bioterrorism and catastrophe response: a quick-reference guide to resources

BACKGROUND

Dentists' responses to catastrophe have been redefined by bioterrorism. Informed response requires accurate information about agents and diseases that have the potential to be used as weapons.

METHODS

The authors reviewed information about the most probable bioterrorist weapons (those from the Center for Disease Control and Prevention's Category A) from the World Wide Web and print journals and distilled it into a resource list that is current, relevant to dentistry and noncommercial. The Web sites cited include those sponsored by federal agencies, academic institutions and professional organizations. The articles cited include those published in English within the last six years in refereed journals that are available in most higher education institutions.

RESULTS

The authors present the information in a table that provides a quick-reference guide to resources describing agents and diseases with the greatest potential for use as weapons: anthrax, botulism, plague, smallpox, tularemia and viral hemorrhagic fevers. This article presents Web site and journal citations for background and patient-oriented information (fact sheets), signs and symptoms, and prophylactic measures and treatment for each of the agents and diseases. The table facilitates quick access to this information, especially in an emergency. This article also points out guidelines for response should a suspected attack occur.

CONCLUSIONS

Armed with information about biological weapons, dentists can provide faster diagnosis, inform their patients about risks, prophylaxis or treatment and rethink their own role in terrorism response.

CLINICAL IMPLICATIONS

Fast, accurate diagnosis limits the spread of exceptionally contagious diseases. Providing accurate information to patients minimizes misinformation and the associated public fear and panic that, unchecked, could overwhelm health care systems.

Francisella novicida LPS has greater immunobiological activity in mice than F. tularensis LPS, and contributes to F. novicida murine pathogenesis

To further understand the role of LPS in the pathogenesis of Francisella infection, we characterized murine infection with F. novicida, and compared immunobiological activities of F. novicida LPS and the LPS from F. tularensis live vaccine strain (LVS). F. novicida had a lower intradermal LD(50) in BALB/cByJ mice than F. tularensis LVS, and mice given a lethal F. novicida dose intraperitoneally died faster than those given the same lethal F. tularensis LVS dose. However, the pattern of in vivo dissemination was similar, and in vitro growth of both bacteria in bone marrow-derived macrophages was comparable. F. novicida LPS stimulated very modest in vitro proliferation of mouse splenocytes at high doses, but F. tularensis LVS LPS did not. Murine bone marrow macrophages treated in vitro with F. novicida LPS produced IL12 and TNF-alpha, but did not produce detectable interferon-gamma, IL10, or nitric oxide; in contrast, murine macrophages treated with F. tularensis LVS LPS produced none of these mediators. In contrast to clear differences in stimulation of proliferation and especially cytokines, both types of purified LPS stimulated early protection against lethal challenge of mice with F. tularensis LVS, but not against lethal challenge with F. novicida. Thus, although LPS recognition may not be a major factor in engendering protection, the ability of F. novicida LPS to stimulate the production of proinflammatory cytokines including TNF-alpha likely contributes to the increased virulence for mice of F. novicida compared to F. tularensis LVS.

Tularaemia

Tularaemia is a zoonotic bacterial disease of the Northern hemisphere. The causative agent, Francisella tularensis, is spread to humans by direct contact with infected rodents or lagomorphs, aerogenic exposure, ingestion of contaminated food or water, or by arthropod bites. The prevalence of tularaemia shows a wide geographic variation. In some endemic regions, outbreaks occur frequently, whereas nearby rural parts of a country may be completely free. F. tularensis is a facultative intracellular pathogen and its primary mammalian target cell is the mononuclear phagocyte. When tularaemia is acquired via the skin, a primary ulcer is often detected and in general, regional lymph nodes become prominently enlarged. When contracted by inhalation, the disease may present with pneumonia. Nearly as frequent, however, is the development of fever and general illness with no respiratory symptoms and no pulmonary radiological changes. When present, the changes vary widely and may sometimes include hilar enlargement indistinguishable from that of lymphoma. Within an outbreak, the first case of tularaemia is not always readily diagnosed. A decade may have lapsed since the disease was encountered and its existence may be more or less forgotten. The difficulty refers especially to the respiratory form, in which symptoms are less specific. In cases of atypical pneumonia or acute febrile disease with no local symptoms, a history of exposure to hares or rodents or merely living in an endemic region should be sufficient to include tularaemia among differential diagnoses. The microbiological diagnosis of tularaemia relies mainly on serology, and the treatment on broad-spectrum antibiotics. For decades, a live vaccine has been successfully used in risk groups but is presently not available due to difficulties in standardisation.

Gastrointestinal and hepatic manifestations of tickborne diseases in the United States

Signs and symptoms related to the gastrointestinal tract and liver may provide important clues for the diagnosis of various tickborne diseases prevalent in different geographic areas of the United States. We review clinical and laboratory features that may be helpful in detecting a tickborne infection. Physicians evaluating patients who live in or travel to areas where tickborne diseases are endemic and who present with an acute febrile illness and gastrointestinal manifestations should maintain a high index of suspicion for one of these disease entities, particularly if the patient has received a tick bite. If detected early, many of these potentially serious illnesses can be easily and effectively treated, thereby avoiding serious morbidity and even death.

Threats in bioterrorism. I: CDC category A agents

Although once considered unlikely, bioterrorism is now a reality in the United States since the anthrax cases began appearing in the fall of 2001. Intelligence sources indicate there are many countries and terrorist organizations that either possess biological weapons or are attempting to procure them. In the future it is likely that we will experience additional acts of bioterrorism. The CDC category A agents represent our greatest challenge because they have the potential to cause grave harm to the medical and public health systems of a given population. Thus, it is imperative that plans be developed now to deal with the consequences of an intentional release of any one or more of these pathogens.

Rapid laboratory diagnosis of ulceroglandular tularemia with polymerase chain reaction

Tularemia is a zoonotic disease which, in Scandinavia, is usually acquired through a mosquito bite. As the infecting organism, Francisella tularensis, is highly virulent the culturing of F. tularensis has generally been avoided. PCR offers a safe way to rapidly confirm diagnosis of tularemia. The case of a 9-y-old boy with ulceroglandular tularemia is presented. The diagnosis was made rapidly with DNA amplification from a pus specimen. The efficacy of ciprofloxacin treatment of tularemia in children is also discussed.

Tularemia epidemic in northwestern Spain: clinical description and therapeutic response

This study describes the clinical characteristics of tularemia in Spain's first epidemic outbreak and the therapeutic response and compares the efficacy of 3 antibiotics (streptomycin, ciprofloxacin, and doxycycline). For 142 cases of tularemia, the therapeutic failure rate was 22.5%; ciprofloxacin was the antibiotic with the lowest percentage of therapeutic failures and with the fewest side effects.

The threat of biological terrorism: a public health and infection control reality

Bioterrorism is an emerging public health and infection control threat. Potential biological agents include smallpox, anthrax, plague, tularemia, botulinum toxin, brucellosis, Q fever, viral encephalitis, hemorrhagic fever, and staphylococcal enterotoxin B. An understanding of the epidemiology, clinical manifestations, and management of the more likely candidate agents is critical to limiting morbidity and mortality from a biological event. Effective response requires an increased index of suspicion for unusual diseases or syndromes, with prompt reporting to health authorities to facilitate recognition of an outbreak and subsequent intervention. Hospital epidemiology programs will play a crucial role in this effort.

[Tularemia, "volume" two]

As a continuation of Libich's monograph (Tularemie. Prague, Avicenum 1981) the author presents findings assembled in experiments pertaining to postinfectious immunity on a model of intracellular infection with the microorganism Francisella tularensis.

Cytokine expression in the liver during the early phase of murine tularemia

Cytokine expression was determined in the livers of mice inoculated subcutaneously with Francisella tularensis LVS. During the first 48 h of infection, there was a logarithmic increase of bacteria in the liver, with a doubling time of 2.5 h. Within 48 h, tumor necrosis factor alpha (TNF-alpha), interleukin 10 (IL-10), IL-12, and gamma interferon (IFN-gamma) mRNAs were expressed, and production of TNF-alpha and IFN-gamma was demonstrated. There was no expression within 96 h of mRNA from IL-2, IL-3, or IL-4. After subcutaneous inoculation of heat-killed LVS, no expression of any of the cytokine mRNAs and no increase in the levels of TNF-alpha or IFN-gamma occurred. The expression of TNF-alpha, IL-12, and IFN-gamma is held to be important to evoke an early T-cell-independent host defense against F. tularensis as well as to drive the expansion of a protective Th1 cell response.

Persistence of cell-mediated immunity and decline of humoral immunity to the intracellular bacterium Francisella tularensis 25 years after natural infection

The humoral and cell-mediated immune responses to the facultative intracellular pathogen Francisella tularensis were studied in subjects who had tularemia 25 years earlier. Serum agglutinin titers were low. Of 53 subjects, only 2 had a titer > 40. The F. tularensis-induced T cell response, on the other hand, was vigorous and in fact similar in magnitude to the response to purified protein derivative (PPD) of Mycobacterium tuberculosis. T cells from 44 of 52 subjects showed a significant (P < .05) proliferative response in vitro to each of four membrane proteins of F. tularensis. Only 2 subjects did not respond to any of the proteins. In most cultures from 18 subjects tested, interferon-gamma was produced in response to the proteins. During the last 25 years, tularemia has been reported only rarely in the region where the subjects lived, suggesting that an antigen-specific T cell response may persist after tularemia independently of reexposure to F. tularensis.

Tularemia in children caused by Francisella tularensis biovar palaearctica

Existing data on tularemia infections in children caused by the biovar Francisella tularensis palaearctica (type B) are limited. The case histories of all patients younger than the age of 16 years in northern Finland who had tularemia, based on the antibody response, during the years 1967 to 1986 are reviewed. A total of 67 children, 28 girls and 39 boys, were identified as having had tularemia. The occurrence of the disease varied greatly among years. Most of the cases occurred in July, August and September. The epidemiology differed significantly from that reported for F. tularensis biovar tularensis (type A). This is most probably attributable to the different vector, which was the mosquito in our series, but the tick in areas where type A is common. There were also clear differences in the clinical picture. The ulceroglandular clinical type was the most common. The clinical symptoms and signs were usually quite benign, but the symptoms lasted for a median duration of 26 days. The patients were treated with different antibiotics and there were no differences in the outcome related to the treatment given. Prospective comparative investigations of antibiotic therapy given for tularemia are needed. It is also important to try to identify which strain is causing the disease in each case.

Modifying effects of exercise on clinical course and biochemical response of the myocardium in influenza and tularemia in mice

For a study of the interactions of strenuous physical exercise (daily swimming to exhaustion) and a viral as compared with a bacterial infection with regard to the clinical course and the biochemical response of the myocardium, influenza and tularemia of similar lethality were used in mice. In both infections, expected infection-induced catabolic alterations in the ventricular myocardium were evident 2 days before median lethality was achieved, with a more pronounced wasting in influenza than in tularemia. Exercise before inoculation (preconditioning) was beneficial in that the catabolic effects of both infections were limited and lethality in influenza was reduced. Thus, the myocardial protein-degrading effect of influenza did not occur with preconditioning, and oxidative tissue enzyme activities decreased less. In tularemia, cytochrome c oxidase activity was fully preserved with preconditioning, and activation of catalase was less pronounced. Exercise during ongoing infection counteracted the infection-induced decrease in the activities of glycolytic and oxidative enzymes in tularemia, but lethality and bacterial counts in the spleen were uninfluenced. Conversely, exhaustive exercise in influenza increased lethality and had no significant effect on cardiac enzymes. These exercise models caused no major alterations in activation of lysosomal enzymes (beta-glucuronidase and cathepsin D).

An extended study of the behavioral effects of respiratory Pasteurella tularensis in man

The mean percentage of baseline performance, a measure of average work efficiency, fell approximately 33% during the period of illness ( P. tularensis) of 8 experimental Ss. Four days after treatment, individual performance equaled that of controls (3 double-blind hospital control Ss and a separate control group of 10 Ss), but group-task performances appeared not to have recovered so completely. The findings extend and essentially support those of a previous study (Alluisi, et al., 1971) in which the illness-related decrement in individual performance averaged 25%, with only incomplete recovery 3 days after treatment.

Behavioral effects of infectious diseases: respiratory Pasteurella tularensis in man

Average efficiency in the work of 8 Ss, as measured with the mean percentage of baseline performance, fell about 25% during the period of their illness (P. tularensis). Recovery 3 days after treatment had begun was incomplete, with performance averaging 10 to 15% below that of controls (2 double-blind hospital control Ss and a separate control group of 10 Ss).