Anthrax, tularemia, plague, ebola or smallpox as agents of bioterrorism: recognition in the emergency room

Bioterrorism has become a potential diagnostic consideration in infectious diseases. This article reviews the clinical presentation and differential diagnosis of potential bioterrorist agents when first presenting to the hospital in the emergency room setting. The characteristic clinical features of inhalation anthrax, tularemic pneumonia, plague pneumonia, including laboratory and radiographic finding, are discussed. Ebola vieus and smallpox are also discussed as potential bioterrorist-transmitted infections from the clinical and epidemiologic standpoint. In addition to the clinical features of the infectious diseases mentioned, the article discusses the infectious disease control and epidemiologic implications of these agents when employed as bioterrorist agents. The review concludes with suggestions for postexposure prophylaxis and therapy.

[New molecular biology detection methods for tick-borne infectious agents]

Tick-borne zoonotic pathogens are well known in many areas all over the world. Among the tick-borne transmitted diseases in Switzerland, Lyme disease caused by Borrelia burgdorferi, ehrlichiosis caused by various species of Ehrlichia and tick-borne encephalitis caused by the tick-borne encephalitis virus (TBEV) are the most important zoonotic diseases. Early diagnosis and treatment is necessary to prevent fatal infections and chronic damage to various tissues. Due to the variety of uncharacteristic clinical signs, tick-borne diseases are not easily recognized. Diagnosis is based on clinical findings, a record of tick exposure, and direct or indirect detection of the pathogen. Here we discuss briefly the most important tick-borne infections and their diagnosis with emphasis on a new molecular diagnostic tool--the real-time TaqMan PCR--and its importance for the diagnosis of tick-borne pathogens.

A procedure for differentiating between the intentional release of biological warfare agents and natural outbreaks of disease: its use in analyzing the tularemia outbreak in Kosovo in 1999 and 2000

The events of 11 September and the subsequent anthrax outbreaks in the USA have opened the world's eyes to the threat posed by terrorist groups, criminal organizations and lone operators who will stop at nothing to achieve their goals. The open or covert use of pathogens and toxins as biological warfare agents can no longer be ruled out. Against this background, the appearance of an unusual disease must be studied in order to clarify whether it is a natural or artificially caused occurrence. This issue was recently raised in discussions with local representatives and relief organizations during a tularemia epidemic in Kosovo from October 1999 to May 2000. This paper will present a procedure which attempts to use certain criteria to identify or rule out the use of biological warfare agents in the event of an unusual outbreak of disease. Data and findings gathered by routine epidemiologic and microbiological studies often provide only an indirect answer to this problem. For this reason, various criteria were formulated and points allocated to represent their importance, allowing us to deduce in a semiquantitative manner the degree of possibility of an artificial genesis of outbreaks. The significance and characterization of each criterion are discussed. An analysis of the tularemia epidemic in Kosovo based on the procedure described here indicates that a deliberate release of the causative agent of tularemia, Francisella tularensis, as a biological warfare agent is doubtful. In this paper, an approach is described to discriminate between the intentional use of biological warfare agents and natural outbreaks of infectious diseases. The developed model is flexible and considers the political, military and social analysis of the crisis-afflicted region, the specific features of the pathogen, and the epidemiologic and clinical characteristics of the epidemic.

Tularemia. A pathogen in nature and a biological weapon

Tularemia as a potential biological weapon is of great concern because F. tularensis is a hardy organism that can be spread with a small inoculum. In addition, tularemia can be contracted through nature, predominately in rural areas. This disease can be spread by a wide variety of animals and can range from skin lesions to multi-organ involvement. The severity varies with amount of inocula, the virulence of the bacterium, and the port of entry. Exposure to aerosolized forms of F. tularensis, the major concern with bioterroism, can rapidly lead to respiratory failure and death. Untreated, other forms of tularemia can spread through the blood stream to other organs, leading to sepsis and death. Early recognition and treatment is tantamount to treatment and prevention of morbidity and mortality. Occupational health nurses are on the front line and must be assertive in identifying risk factors associated with exposure. Furthermore, education of the general population about exposure through nature can potentially decrease the incidence of tularemia. Occupational health nurses, as one of the largest health specialties in the workplace, may be the first contact for the exposed individual. Tularemia is treatable with knowledge of prevention, astute assessment, prompt identification, and treatment. Combined, they are powerful nursing tools in achieving optimal outcomes.

Prevalence of coinfection with Francisella tularensis in reservoir animals of Borrelia burgdorferi sensu lato

INTRODUCTION AND PURPOSE

Studies on Lyme borreliosis and other tick-borne zoonoses in the Austrian and Slovakian borderland, a region endemic for tularemia, revealed a relatively high prevalence of infection with Borrelia burgdorferi s.l. and Francisella tularensis in small terrestrial mammals, as well as in the ticks, during a one-year survey. The occurrence of coinfection with the agents of Lyme borreliosis and tularemia was assessed in different species of rodents.

METHODS

Organs of small mammals, live-trapped mostly in six-week intervals from May 1994 to April 1995, were cultured on appropriate media in order to grow borreliae and F. tularensis.

RESULTS

Infection with B. burgdorferi s.l. and also with F. tularensis was found in all the most abundant rodent species. A significant difference was observed in the time period of isolation of these agents. Borrelia was cultured from May to January (PCR detected borrelia up to April), while F. tularensis was isolated from August to December. Coinfection was seen in two species of voles, Clethrionomys glareolus trapped in August and Microtus arvalis in October. The Borrelia strains isolated from these animals were identified as B. garinii. Isolates of F. tularensis belonged to the subspecies holarctica, biovar II.

CONCLUSIONS

Results obtained indicate that in endemic regions for tularemia the prevalence of infection with borreliae could be modified in different animal species mainly during epizootic outbreaks of tularemia.

The ascendancy of Amblyomma americanum as a vector of pathogens affecting humans in the United States

Until the 1990s, Amblyomma americanum was regarded primarily as a nuisance species, but a tick of minor importance as a vector of zoonotic pathogens affecting humans. With the recent discoveries of Ehrlichia chaffeensis, Ehrlichia ewingii, and "Borrelia lonestari," the public health relevance of lone star ticks is no longer in question. During the next 25 years, the number of cases of human disease caused by A. americanum-associated pathogens will probably increase. Based on current trajectories and historic precedents, the increase will be primarily driven by biological and environmental factors that alter the geographic distribution and intensity of transmission of zoonotic pathogens. Sociologic and demographic changes that influence the likelihood of highly susceptible humans coming into contact with infected lone star ticks, in addition to advances in diagnostic capabilities and national surveillance efforts, will also contribute to the anticipated increase in the number of recognized cases of disease.

Bacterial pathogens as biological weapons and agents of bioterrorism

Bacterial pathogens have been identified as agents that have been, or could be, used as weapons of biological warfare and/or biological terrorism. These agents are relatively easily obtained, prepared, and dispersed, either as weapons of mass destruction or for more limited terrorist attacks. Although phylogenetically diverse, these agents all have the potential for aerosol dissemination. Physicians in the United States and most of the developed world have never encountered most of these agents and the diseases they produce. Public health programs must be prepared, and individual primary care providers must be able to recognize, diagnose, treat, and prevent infection with these agents.

[Tularemia as a biological weapon]

Tularemia is a zoonosis, caused by the Gram-negative bacterium, Francisella tularensis. The organism penetrates the human body through interrupted skin or mucous membranes, via animal contact or bites from ticks, deer-flies and mosquitoes. Contaminated aerosol and water are alternative modes of transmitting the germ through the respiratory and alimentary tracks. In light of its high infectivity in aerosol and its offensive occupation in the past, tularemia may appear in a biological warfare context. After an incubation period of 3-5 days, the disease begins with systemic symptoms, which abate, leaving a clinical picture, dominated by one of the listed patterns: ulceroglandular, typhoidal, glandular, occuloglandular, pharyngeal or pneumonic. Diagnosis and identification of the bacterium is difficult and even hazardous. Most diagnoses are established by serology which is positive in 50-70% of the patients after 2 weeks of illness, and in most of them by 4-8 weeks. The treatment of choice is streptomycin intra-muscular, or gentamicin intra-venous for 10-14 days. Prophylaxis may be achieved by tetracycline treatment, beginning up to 24 hours from exposure, for 2 weeks, or by a live attenuated, investigational vaccine. Nevertheless, post-exposure, or even better so, pre-exposure intervention is the most effective way of preventing the devastating results of the attack.

[A water-borne epidemic of tularemia in Chlumcany]

During an epidemic of tularaemia in Chlumcany in December 2000 48 people, 36 adults, 12 children fell ill. In the patients the oroglandular form predominated which was diagnosed 46 times. None of the patients died. The vehicle of the infection was inadequately treated water which was used by the patients for the preparation of soda water and for washing. Using the polymerase chain reaction francisellae were detected in two water samples.

Tularemia outbreak investigation in Kosovo: case control and environmental studies

A large outbreak of tularemia occurred in Kosovo in the early postwar period, 1999-2000. Epidemiologic and environmental investigations were conducted to identify sources of infection, modes of transmission, and household risk factors. Case and control status was verified by enzyme-linked immunosorbent assay, Western blot, and microagglutination assay. A total of 327 serologically confirmed cases of tularemia pharyngitis and cervical lymphadenitis were identified in 21 of 29 Kosovo municipalities. Matched analysis of 46 case households and 76 control households suggested that infection was transmitted through contaminated food or water and that the source of infection was rodents. Environmental circumstances in war-torn Kosovo led to epizootic rodent tularemia and its spread to resettled rural populations living under circumstances of substandard housing, hygiene, and sanitation.

[Outbreak of tularemia in the Republic of Dagestan]

In Daghestan in the focus of the flood-plain swamp type 64 persons fell ill with tularemia in 1999. During the epizootological survey 8 Francisella tularensis strains were isolated from vectors and carriers and in 7 samples taken from open water reservoirs, as well as in 1 sample obtained from Ixodes ticks, tularemia antigen was detected. Humans were infected mainly by the transmissive route, as found in 71.8% of patients. 28% of patients were infected through contacts. The disease took mainly a mild course, registered in 95.6% of patients. The disease affected those persons who had not been immunized against tularemia.

[Epizootic significance of white-toothed shrews in the natural focus of steppe type tularemia in the Stavropol' region]

The observations indicate that anthropogenic activities cause structural changes with time among tularemia pathogen carriers in the microfocus. The epizootic and epidemic values of animal species, such as dwarf hamsters and house mice, decrease while those of insect-eating animals, namely white-toothed shrews that refer to Group II increase, in terms of tularemia infection susceptibility. In white-toothed shrews, tularemia infection rates are 4-6-times greater than those in other small mammals that refer to Group I.

[Tularemia--an old and a new problem in the South Moravia Region]

BACKGROUND

The first epidemic of ulceroglandular forms of tularemia acquired in coincidence with the manipulation with tularaemic hares took place in 1936 in the surroundings of Breclav and Valtice. The largest epidemic took place in the 1960's when hundreds of agricultural workers in the initial phases of the production of sugar within sugar refineries were afflicted by pulmonary forms of this disease. In the subsequent period which was interrupted only by smaller local epidemics, the number of new cases were gradually decreasing to the minimum at the beginning of 1990's. However, since 1994, the number of cases has began to increase again, namely those afflicted by ulceroglandular and oroglandular forms. OBJECTIVES [corrected]: In consequence of the long absence of this disease in clinical practice, the diagnostic awareness has decreased, and therefore the author has decided to indicate and review the current basic data on epidemiology and clinical manifestations of tularaemia.

GROUP OF PATIENTS AND METHODS

The author has analysed the documentation of 577 of adults afflicted by tularemia and medically treated at the clinic of the Faculty Hospital in Brno in the period form 1959 to 1999. The study reviews the onset of the disease and the pathway of transmission of infection and its clinical manifestation.

MAIN RESULTS

Following the long-termed sporadic occurrence of tularaemia after major epidemics of pulmonary forms of this disease in 1960's, interrupted only by smaller local epidemics, the incidence has began to increase again in 1994. The number of pulmonary forms has decreased whereas the occurrence of ulcerulceroglandular and oroglandular forms has increased. Hares have become the source of infection again.

CONCLUSIONS

The fact that tularemia has repeatedly become a threat in Southern Moravia should be taken into account in the assessment of diagnosis in cases with unclear lymphadenitis and febrile states which defy the penicillin treatment especially in winter. (Tab. 3, Fig. 3, Ref. 23.)

Tularemia: a case transmitted from a sheep

Tularemia is an arthropod-borne infectious disease caused by Francisella tularensis, a gram-negative microorganism that normally resides in a wide range of wild and domestic animals. The disease is characterized by a sudden onset with high fever, headache, malaise, chills, myalgia, and arthralgia. A short time after exposure, an inflamed and ulcerated lesion rapidly appears at the site of entry. A regional lymphadenopathy follows the cutaneous presentation. Cultures from the lesions or blood generally give negative results. Histopathologic examination reveals either a nonspecific inflammatory infiltrate or an infectious granuloma. The most useful laboratory procedure in the diagnosis of tularemia is serologic tests. Streptomycin, gentamicin, and tetracycline are the drugs of choice in the treatment. Quinolones are also effective. Tularemia is fairly rare in Turkey. We present a typical case of ulceroglandular tularemia transmitted from a sheep to a young man.

Francisella tularensis in Dermacentor reticulatus ticks from the Czech Republic and Austria

Host-seeking adult Dermacentor reticulatus ticks were examined for the prevalence of Francisella tularensis in an active natural focus of tularemia along the lower reaches of the Dyje (Thaya) river in South Moravia (Czech Republic) and adjacent Lower Austria, in four localities of the flood plain forest-meadow ecosystem during the spring of 1996. The ticks were pooled (10 male or female ticks per group) and inoculated subcutaneously in 4-week-old SPF mice. Dead mice were sectioned, the spleens were homogenized in PBS and passaged in mice, and impression smears from the spleens, liver and heart blood were stained by Giemsa. Twenty-five isolates of F. tularenis were recovered from 1098 pooled D. reticulatus: the minimum infection rate (MIR) is 2.3%. MIRs for 629 female and 469 male D. reticulatus were 2.4% and 2.1%, respectively. The prevalence varied according to locality, but did not significantly differ between the Moravian (2.2%) and Austrian (2.8%) sites. The monitoring of D. reticulatus for F. tularensis might be a valuable contribution to the surveillance of tularemia in Europe.

[Tularemia after tick bite in Vestfold]

Direct contact with rodents or their faeces is a well-known risk factor for contracting tularaemia in Norway. Both insects and ticks can act as vectors of tularaemia, but transmission by this route has not previously been described in this country. We report three cases of serologically confirmed ulceroglandular tularaemia on a small island in Southern Norway, an area in which tularaemia has not previously been known to occur. Tick bites preceded infection in two of the patients. The third patient may also have become infected through a tick or insect bite. Diagnosis was made late in all cases, causing a delay in appropriate treatment. Two of the patients were successfully treated with ciprofloxacin. Our experience and previous reports suggest that quinolones should be considered as the first choice of drugs in the treatment of tularaemia in Norway.

Mosquitoes (Diptera: Culicidae), in contrast to ticks (Acari: Ixodidae), do not carry Francisella tularensis in a natural focus of tularemia in the Czech Republic

In total, 9,167 mosquitoes (Aedes spp.) and 1,987 ixodid ticks--1,423 Dermacentor reticulatus (F.), 504 Ixodes ricinus (L.), and 60 Haemaphysalis concinna Koch--were examined in an active enzootic focus (floodplain forest-meadow ecosystem) of tularemia in South Moravia. Czech Republic. Although no F. tularensis was detected in mosquitoes or H. concinna, 30 isolates were recovered from D. reticulatus (infection rate, 2.1%) and 1 isolate from I. ricinus (infection rate, 0.2%). Ixodid ticks, especially D. reticulatus, but not mosquitoes serve as vectors (and perhaps reservoirs) of F. tularensis at this natural focus.

[Analysis of the incidence and routes of transmission of tularemia in Slovakia]

The morbidity from tularaemia in Slovakia has since the epidemic incidence in the sixties a declining trend. The mean annual morbidity rate declined from 5.5 per 10(5) population in 1960-1969 to 0.3 in 1980-1994 and is markedly influenced by the incidence of tularaemia in the well known epidemic area in western Slovakia where in 1985 also the first cases of transmission of tularaemia by ticks were recorded in Slovakia. During the last decade (1985-1994) in Slovakia 126 cases were notified, out of them 96.8% in the western Slovakian region, more than half of the cases were recorded in the districts of Nitra and Nové Zámky. The analysis of the incidence of the disease in western Slovakia as compared with the previous decade (1975-1984) drew attention to marked changes in the epidemiology of tularaemia and a rise of the cases transmitted from other sources of infection than hares and by ectoparasites. Their ratio is almost 66%, from that 20.5% formed by cases transmitted by ticks (15.6%) and by other arthropods (4.9%). In the majority of patients with ticks in the case-history the ulceroglandular form of the disease was recorded (79%), with the primary affection at the site of the tick-bite, in the majority with lymphadenitis in the inguinal area (63.2%). The majority of the cases was recorded in summer, most frequently in occupational groups: pupils and students, forestry workers and mainly other occupations. The results of an epidemiological survey and data on the prevalence of for ticks infected with Francisella tularensis in the endemic area of Slovakia indicate that the tick-borne of tularaemia in humans Central European ecological conditions is probably more frequent than hitherto assumed.