Three related cases of cutaneous anthrax in France: clinical and laboratory aspects

An Outbreak of Human Systemic Anthrax, including One Case of Anthrax Meningitis, Occurred in Calabria Region (Italy): A Description of a Successful One Health Approach

In this report, three cases of human cutaneous anthrax are described, one complicated by meningitis, and all were linked to a single infected bullock. A 41-year-old male truck driver, along with two male slaughterhouse workers, 45 and 42, were hospitalized for necrotic lesions of the arm associated with edema of the limb and high fever. All three patients were involved in transporting a bullock to the slaughterhouse. Microbiological examination on the prescapular lymph node and a piece of muscle from the bullock carcass showed the presence of Bacillus anthracis. The three patients underwent a biopsy of the affected tissues, and all samples tested positive for B. anthracis DNA using PCR. Furthermore, the truck driver also complained of an intense headache, and a CSF sampling was performed, showing him positive for B. anthracis by PCR, confirming the presumptive diagnosis of meningitis. Fast diagnosis and appropriate treatment are crucial for the management of human anthrax. Cooperation between human and veterinary medicine proved successful in diagnosing and resolving three human anthrax cases, confirming the reliability of the One Health approach for the surveillance of zoonoses.

Review: The risk of contracting anthrax from spore-contaminated soil - A military medical perspective

Anthrax is an infectious disease of relevance for military forces. Although spores of Bacillus anthracis obiquitously occur in soil, reports on soil-borne transmission to humans are scarce. In this narrative review, the potential of soil-borne transmission of anthrax to humans is discussed based on pathogen-specific characteristics and reports on anthrax in the course of several centuries of warfare. In theory, anthrax foci can pose a potential risk of infection to animals and humans if sufficient amounts of virulent spores are present in the soil even after an extended period of time. In praxis, however, transmissions are usually due to contacts with animal products and reported events of soil-based transmissions are scarce. In the history of warfare, even in the trenches of World War I, reported anthrax cases due to soil-contaminated wounds are virtually absent. Both the perspectives and the experience of the Western hemisphere and of former Soviet Republics are presented. Based on the accessible data as provided in the review, the transmission risk of anthrax by infections of wounds due to spore-contaminated soil is considered as very low under the most circumstance. Active historic anthrax foci may, however, still pose a risk to the health of deployed soldiers.

An ELISA using a recombinant chimera of protective antigen and lethal factor for serodiagnosis of cutaneous anthrax in India

In this study, an ELISA was developed for simultaneous detection of antibodies against both the important toxins of B. anthracis i.e. protective antigen (PA) and lethal factor (LF). A chimera of PA and LF was made by fusion and cloned and expressed in E. coli. The purified recombinant protein was used in plate ELISA for serodiagnosis of anthrax. The chimera could detect antibodies against both the toxins of Bacillus anthracis. The human serum samples (n = 98) collected from anthrax endemic and non-endemic areas were tested employing ELISA. The ELISA gave sensitivity of 100% (95% Confidence Interval [CI], 92.13 to 100) and specificity of 97.78% (95% Confidence Interval [CI], 88.23 to 99.94) with a J index of 0.97. The efficiency of ELISA was found to be 98.9% with the positive predictive value (PPV) and negative predictive value (NPV) of 97.8% and 100%, respectively. The chimera of PA and LF could be a better diagnostic antigen for serodiagnosis as the assay detects antibodies against both the toxins in early as well delayed infection cases of anthrax. Therefore, it can be a very useful tool for the surveillance as well as for confirmation of cutaneous anthrax cases.

Source and risk factors of a cutaneous anthrax outbreak, Jiangsu, Eastern China, 2012

Anthrax is still a severe public health problem and threat to human health. A cutaneous anthrax outbreak occurred in Jiangsu Province, a non-endemic anthrax region of eastern China, from July to August 2012. Epidemiological and laboratory investigation were initiated to trace the source of infection and identify the risk factors of the outbreak. On 25 July 2012, 17 persons were exposed to a sick cow, which had been imported from northeast China a few days previously. Of the 17 exposed, eight developed symptoms between 1 and 8 days and were diagnosed as cutaneous anthrax cases. Three main genes of Bacillus anthracis were detected from both human and cow meat samples, indicating that the outbreak was associated with this infected cow. A retrospective cohort study showed that contact with blood and presence of skin damage contributed to the case infection with B. anthracis. The outbreak highlights the need to enhance quarantine for imported livestock, which should have been vaccinated prior to importation, the significance of education for high-risk individuals, and training for primary healthcare workers even in anthrax-free areas.

Antimicrobial Treatment for Systemic Anthrax: Analysis of Cases from 1945 to 2014 Identified Through a Systematic Literature Review

Systemic anthrax is associated with high mortality. Current national guidelines, developed for the individualized treatment of systemic anthrax, outline the use of combination intravenous antimicrobials for a minimum of 2 weeks, bactericidal and protein synthesis inhibitor antimicrobials for all cases of systemic anthrax, and at least 3 antimicrobials with good blood-brain barrier penetration for anthrax meningitis. However, in an anthrax mass casualty incident, large numbers of anthrax cases may create challenges in meeting antimicrobial needs. To further inform our understanding of the role of antimicrobials in treating systemic anthrax, a systematic review of the English-language literature was conducted to identify cases of systemic anthrax treated with antimicrobials for which a clinical outcome was recorded. A total of 149 cases of systemic anthrax were identified. Among the identified 59 cases of cutaneous anthrax, 33 were complicated by meningitis (76% mortality), while 26 simply had evidence of the systemic inflammatory response syndrome (4% mortality); 21 of 26 (81%) of this latter group received monotherapy. Subsequent analysis regarding combination antimicrobial therapy was restricted to the remaining 123 cases of more severe anthrax (overall 67% mortality). Recipients of combination bactericidal and protein synthesis inhibitor therapy had a 45% survival versus 28% in the absence of combination therapy (p = 0.07). For meningitis cases (n = 77), survival was greater for those receiving 3 or more antimicrobials over the course of treatment (3 of 4; 75%), compared to receipt of 1 or 2 antimicrobials (12 of 73; 16%) (p = 0.02). Median parenteral antimicrobial duration was 14 days. Combination bactericidal and protein synthesis inhibitor therapy may be appropriate in severe anthrax disease, particularly anthrax meningitis, in a mass casualty incident.

An Aggregate of Four Anthrax Cases during the Dry Summer of 2011 in Epirus, Greece

BACKGROUND

Human anthrax is currently a sporadic disease in Europe, without significant regional clustering.

OBJECTIVE

To report an unexpected aggregate of anthrax cases and correlate local climatic factors with yearly anthrax admissions.

METHODS

Clinical description of a geographical-temporal anthrax aggregate, correlation of disease admissions with local weather data in the period 2001-2014 and literature reports of anthrax clusters from Europe in the last 20 years.

RESULTS

We identified 5 cases, all cutaneous: an unexpected aggregate of 4 cases in mid-summer 2011 (including a probable human-to-human transmission) and a sporadic case in August 2005, all in relatively dry periods (p < 0.05). Remarkably, 3/6 reports of human anthrax aggregates from Europe were observed in Balkan Peninsula countries in the year 2011.

CONCLUSION

In the light of the predicted climatic change, unexpected anthrax aggregates during dry periods in southern Europe underscore the risk of future anthrax re-emergence on this continent.

Anthrax: A disease of biowarfare and public health importance

Bioterrorism has received a lot of attention in the first decade of this century. Biological agents are considered attractive weapons for bioterrorism as these are easy to obtain, comparatively inexpensive to produce and exhibit widespread fear and panic than the actual potential of physical damage. Bacillus anthracis (B. anthracis), the etiologic agent of anthrax is a Gram positive, spore forming, non-motile bacterium. This is supposed to be one of the most potent BW agents because its spores are extremely resistant to natural conditions and can survive for several decades in the environment. B. anthracis spores enter the body through skin lesion (cutaneous anthrax), lungs (pulmonary anthrax), or gastrointestinal route (gastrointestinal anthrax) and germinate, giving rise to the vegetative form. Anthrax is a concern of public health also in many countries where agriculture is the main source of income including India. Anthrax has been associated with human history for a very long time and regained its popularity after Sept 2001 incidence in United States. The present review article describes the history, biology, life cycle, pathogenicity, virulence, epidemiology and potential of B. anthracis as biological weapon.

Genetic diversity of Bacillus anthracis in Europe: genotyping methods in forensic and epidemiologic investigations

Bacillus anthracis, the etiological agent of anthrax, a zoonosis relatively common throughout the world, can be used as an agent of bioterrorism. In naturally occurring outbreaks and in criminal release of this pathogen, a fast and accurate diagnosis is crucial to an effective response. Microbiological forensics and epidemiologic investigations increasingly rely on molecular markers, such as polymorphisms in DNA sequence, to obtain reliable information regarding the identification or source of a suspicious strain. Over the past decade, significant research efforts have been undertaken to develop genotyping methods with increased power to differentiate B. anthracis strains. A growing number of DNA signatures have been identified and used to survey B. anthracis diversity in nature, leading to rapid advances in our understanding of the global population of this pathogen. This article provides an overview of the different phylogenetic subgroups distributed across the world, with a particular focus on Europe. Updated information on the anthrax situation in Europe is reported. A brief description of some of the work in progress in the work package 5.1 of the AniBioThreat project is also presented, including (1) the development of a robust typing tool based on a suspension array technology and multiplexed single nucleotide polymorphisms scoring and (2) the typing of a collection of DNA from European isolates exchanged between the partners of the project. The know-how acquired will contribute to improving the EU's ability to react rapidly when the identity and real origin of a strain need to be established.

Humans and cattle: a review of bovine zoonoses

Infectious disease prevention and control has been among the top public health objectives during the last century. However, controlling disease due to pathogens that move between animals and humans has been challenging. Such zoonotic pathogens have been responsible for the majority of new human disease threats and a number of recent international epidemics. Currently, our surveillance systems often lack the ability to monitor the human-animal interface for emergent pathogens. Identifying and ultimately addressing emergent cross-species infections will require a "One Health" approach in which resources from public veterinary, environmental, and human health function as part of an integrative system. Here we review the epidemiology of bovine zoonoses from a public health perspective.

A field usable qualitative anti-protective antigen enzyme-linked immunosorbent assay for serodiagnosis of human anthrax

Although all mammals, including humans, are vulnerable when they come into direct contact with infected animals, anthrax is primarily a disease of herbivorous animals. In countries like India, cutaneous anthrax is a public health problem in several regions. Hence, a simple and efficacious serodiagnostic assay for large scale surveillance of endemic populations is required. In the present study, a field-usable, qualitative ELISA was developed for serodiagnosis of human anthrax. Results are assessed on a visual basis and no sophisticated instruments are required. Anti-protective antigen (PA) IgG was determined by visual examination of ELISA results of 225 human serum samples (160 from healthy humans, 5 from PA vaccinated individuals and 60 from confirmed anthrax cases). Comparison of the ELISA results with the results obtained from optical density values showed compatible sensitivity and specificity. Assay sensitivity, specificity, and positive and negative predictive values were found to be 100%. The developed assay could be a very useful tool for serological diagnosis of anthrax infection in humans.

Serodiagnosis of human cutaneous anthrax in India using an indirect anti-lethal factor IgG enzyme-linked immunosorbent assay

Anthrax, caused by Bacillus anthracis, is primarily a zoonotic disease. Being a public health problem also in several developing countries, its early diagnosis is very important in human cases. In this study, we describe the use of an indirect enzyme-linked immunosorbent assay (ELISA) for detection of anti-lethal factor (anti-LF) IgG in human serum samples. A panel of 203 human serum samples consisting of 50 samples from patients with confirmed cutaneous anthrax, 93 samples from healthy controls from areas of India where anthrax is nonendemic, 44 samples from controls from an area of India where anthrax is endemic, and 16 patients with a disease confirmed not to be anthrax were evaluated with an anti-LF ELISA. The combined mean anti-LF ELISA titer for the three control groups was 0.136 ELISA unit (EU), with a 95% confidence interval (CI) of 0.120 to 0.151 EU. The observed sensitivity and specificity of the ELISA were 100% (95% CI, 92.89 to 100%) and 97.39% (95% CI, 93.44 to 99.28%), respectively, at a cutoff value of 0.375 EU, as decided by receiver operating characteristic (ROC) curve analysis. The likelihood ratio was found to be 49.98. The positive predictive value (PPV), negative predictive value (NPV), efficiency, and Youden's index (J) for reliability of the assay were 92.5%, 100%, 98.02%, and 0.97, respectively. The false-positive predictive rate and false-negative predictive rate of the assay were 2.61% and 0%. The assay could be a very useful tool for early diagnosis of cutaneous anthrax cases, as antibodies against LF appear much earlier than those against other anthrax toxins in human serum samples.

Anti-protective antigen IgG enzyme-linked immunosorbent assay for diagnosis of cutaneous anthrax in India

Anthrax caused by Bacillus anthracis is a public health problem in several developing countries whose main source of income is farming. Anthrax is a disease of herbivorous animals, and humans can be infected by handling infected animals or contaminated animal products. Specific diagnostic tests are unavailable in India for the detection and confirmation of cutaneous anthrax in humans. Here, we describe the development of an enzyme-linked immunosorbent assay (ELISA) for detection of serum antibodies against Bacillus anthracis protective antigen in the Indian population. A total of 405 serum samples collected from different groups were tested by the developed ELISA. The assay provided a specificity of 99.41% (95% confidence interval [CI], 97.89 to 99.93) and a sensitivity of 100% (CI, 94.4 to 100) using a cutoff value of 0.29 ELISA unit (EU). The positive predictive value (PPV) and negative predictive value (NPV) of the assay were 97% and 100%, respectively. The efficiency and J index for the reliability of the assay were 99.5% and 0.994, respectively. The assay can be a very useful tool for surveillance as well as for diagnosis of cutaneous anthrax cases in India.

[Public health surveillance and assessment of emerging infectious threats: method and criteria for risk analysis]

One of the objectives of the surveillance systems implemented by the French National Institute for Public Health Surveillance is to detect communicable diseases and to reduce their impact. For emerging infections, the detection and risk analysis pose specific challenges due to lack of documented criteria for the event. The surveillance systems detect a variety of events, or "signals" which represent a potential risk, such as a novel germ, a pathogen which may disseminate in a non-endemic area, or an abnormal number of cases for a well-known disease. These signals are first verified and analyzed, then classified as: potential public health threat, event to follow-up, or absence of threat. Through various examples, we illustrate the method and criteria which are used to analyze and classify these events considered to be emerging. The examples highlight the importance of host characteristics and exposure in groups at particular risk, such as professionals in veterinarian services, health care workers, travelers, immunodepressed patients, etc. The described method should allow us to identify future needs in terms of surveillance and to improve timeliness, quality of expertise, and feedback information regarding the public health risk posed by events which are insufficiently documented.