Plague in Disguise: The Discovery of Occult Buboes on Surgical Procedure or Autopsy.

Introduction: Bubonic plague classically manifests as a painful, swollen superficial lymph node (bubo) that is readily apparent on physical examination. However, patients occasionally present with buboes formed in deep lymph nodes, which are difficult to detect and can lead to delays in diagnosis and treatment. To better characterize this phenomenon, we conducted a review of the published literature to identify reports of occult buboes among patients with plague. Methods: Articles were identified from two sources: a systematic review on plague treatment, and a search of the PubMed Central database. Articles were eligible if they described a patient with plague who had (1) no evidence of lymphadenopathy on examination; and (2) at least one bubo discovered during surgery or autopsy. Results: Six patients with occult buboes were identified among 5120 articles screened. The majority were male (n = 4/6) and three were <15 years of age. Fever (n = 6/6), leukocytosis (n = 5/6), and abdominal pain or distention (n = 4/6) were the most common signs and symptoms. Initial diagnoses included other bacterial infections, appendicitis, or acute abdomen. Four patients received at least one antimicrobial effective against Yersinia pestis; however, some experienced delayed treatment due to late diagnosis of plague. Occult buboes were discovered in retroperitoneal (n = 2), inguinal/femoral (n = 2), mesenteric (n = 2), axillary (n = 1), and mediastinal (n = 1) regions. Four of the six patients died. Conclusions: Patients with occult buboes experienced delays in the diagnosis of plague and a high fatality rate. Clinicians in plague-endemic areas should consider the presence of occult buboes among patients with compatible symptoms and exposure history.

[Rapidly fatal septicemic plague secondary to undiagnosed primary bubonic plague: case report]. / Peste septicémica rápidamente fatal secundaria a peste bubónica primaria inicialmente no diagnosticada: reporte de caso.

Plague is a re-emerging disease caused by the bacteria Yersinia pestis. Humans usually get the disease through the bite of an infected flea. Plague is a fulminant systemic disease, with pneumonic plague being the most lethal form. Late diagnosis is one of the main causes of mortality and spread of the disease, as it limits the effectiveness of control measures. We present the case of a 42-year-old male, who had previously traveled to an endemic plague area and then presented hyperpyrexia, hypotension, and inflammatory inguinal adenopathy. Despite the very characteristic clinical picture, nobody (before admission to our hospital) suspected plague. An effective combination of antibiotics and intensive treatment was initiated only on the fifth day of illness. The patient went into septic shock, respiratory failure, and death. Plague was confirmed by polymerase chain reaction (PCR). This case emphasizes the importance of having a high suspicion rate for plague.

La peste es una enfermedad reemergente causada por Yersinia pestis. Los humanos generalmente adquieren la enfermedad por picaduras de pulgas. La peste es una enfermedad sistémica fulminante, siendo la peste neumónica la forma más letal. El diagnóstico tardío es una de las principales causas de mortalidad y diseminación de la enfermedad, dado que limita la efectividad de las medidas de control. Presentamos el caso de un varón de 42 años, que previamente había viajado a una zona endémica de peste, y luego presentó hiperpirexia, hipotensión, y adenopatía inguinal inflamatoria. A pesar del cuadro clínico muy característico, nadie (antes del ingreso a nuestro hospital) sospechó peste. Se inició una combinación antibiótica efectiva y tratamiento intensivo recién al quinto día de enfermedad. El paciente evolucionó con shock séptico, falla respiratoria, y muerte. Se confirmó peste por reacción en cadena de polimerasa (PCR). Este caso enfatiza la importancia de tener un alto índice de sospecha para peste.

Peste septicémica rápidamente fatal secundaria a peste bubónica primaria inicialmente no diagnosticada: reporte de caso / Rapidly fatal septicemic plague secondary to undiagnosed primary bubonic plague: case report

RESUMEN La peste es una enfermedad reemergente causada por Yersinia pestis. Los humanos generalmente adquieren la enfermedad por picaduras de pulgas. La peste es una enfermedad sistémica fulminante, siendo la peste neumónica la forma más letal. El diagnóstico tardío es una de las principales causas de mortalidad y diseminación de la enfermedad, dado que limita la efectividad de las medidas de control. Presentamos el caso de un varón de 42 años, que previamente había viajado a una zona endémica de peste, y luego presentó hiperpirexia, hipotensión, y adenopatía inguinal inflamatoria. A pesar del cuadro clínico muy característico, nadie (antes del ingreso a nuestro hospital) sospechó peste. Se inició una combinación antibiótica efectiva y tratamiento intensivo recién al quinto día de enfermedad. El paciente evolucionó con shock séptico, falla respiratoria, y muerte. Se confirmó peste por reacción en cadena de polimerasa (PCR). Este caso enfatiza la importancia de tener un alto índice de sospecha para peste.

ABSTRACT Plague is a re-emerging disease caused by the bacteria Yersinia pestis. Humans usually get the disease through the bite of an infected flea. Plague is a fulminant systemic disease, with pneumonic plague being the most lethal form. Late diagnosis is one of the main causes of mortality and spread of the disease, as it limits the effectiveness of control measures. We present the case of a 42-year-old male, who had previously traveled to an endemic plague area and then presented hyperpyrexia, hypotension, and inflammatory inguinal adenopathy. Despite the very characteristic clinical picture, nobody (before admission to our hospital) suspected plague. An effective combination of antibiotics and intensive treatment was initiated only on the fifth day of illness. The patient went into septic shock, respiratory failure, and death. Plague was confirmed by polymerase chain reaction (PCR). This case emphasizes the importance of having a high suspicion rate for plague.

Pestis Minor: The History of a Contested Plague Pathology.

Pestis minor is a pathological category that at the height of the third plague pandemic (1894-1959) fueled extensive debate and research among medical scientists. Referring to an attenuated or benign form of plague, evidence of pestis minor or pestis ambulans was produced in medical reports across the world so as to raise the question of whether the disease could survive measures against it by means of temporary transformation. Afflicting its victims only by the slightest lymphatic swellings, this theory went, the disease could thus lurk in the human body until conditions allowed it to break out again in its true, malignant form. This article draws for the first time a history of this contested pathology, the diagnostic and epidemiological questions raised by it, and the way in which it came to play a significant role in debates about the nature of plague at the turn of the nineteenth century.

Seroprevalence and spatial distribution dynamics of Yersinia pestis antibodies in dogs and cats from plague foci in the State of Ceará, Northeastern Brazil

Abstract INTRODUCTION: In Brazil, the plague is established in several foci located mainly in the northeastern part of the country, where it alternates between active and quiescent periods. These foci in the State of Ceará have high epidemiological importance. In addition to other plague detection activities, plague areas can be monitored through serological surveys of dogs and cats (domestic carnivores), which, following feeding on plague-infected rodents, can develop mild to severe forms of the disease and produce long-lasting antibodies. This study aimed to characterize the circulation dynamics and spatial distribution of Yersinia pestis antibodies in dogs and cats in plague foci areas of Ceará. METHODS: An ecological study was conducted to analyze the temporal series and spatial distribution of secondary data obtained from domestic carnivore serum surveillance in Ceará's plague areas from 1990 to 2014. RESULTS: Joinpoint analysis revealed that the overall trend was a reduction in antibody-positive animals. The mean proportion of antibody-positivity during the whole study period was 1.5% (3,023/203,311) for dogs, and 0.7% (426/61,135) for cats, with more than 4% antibody-positivity in dogs in 1997 and 2002. Antibody titers ranging from 1/16 to 1/64 were frequent. Despite fluctuations and a significant reduction, in recent years, there were antibody-positive animals annually throughout the study period, and the localities containing antibody-positive animals increased in number. CONCLUSION: Yersinia pestis is actively circulating in the study areas, posing a danger to the human population.

[Development and testing of an enzyme immunoassay-based monoclonal test system for the detection of the Yersinia pestis V antigen].

An enzyme immunoassay-based test system for Y. pestis V antigen detection was developed. The specificity and sensitivity of this system met the requirements for medical immunobiological preparations for the identification of causative agents of highly fatal diseases. The sensitivity of the test system was assessed, and its high specificity was also demonstrated: the test system did not detect bacterial cells of closely related (four Y. pseudotuberculosis strains) and heterologous microorganism strains. The test system developed was able to detect the V antigen at concentrations as low as 2.0 ng/mL in cells of nine experimental Y. pestis cultures. The obtained preparation can be recommended for use in laboratory diagnostics of plaque.

Aplicação da técnica Loop-mediated isothermal amplification (LAMP) no desenvolvimento de um teste para o diagnóstico da peste / Application of the technique Loop-mediated isothermal amplification (LAMP) in developing a test for the plague diagnosis

A peste, infecção causada pela bactéria Yersinia pestis, é uma zoonose primária de roedores, geralmente transmitida por pulgas, que infecta humanos e outros mamíferos. O diagnóstico bacteriológico tradicional da peste pode ser comprometido pela qualidade das amostras coletadas em áreas remotas, transportadas inadequadamente e recebidas no laboratório semanas após a coleta. Técnicas de diagnóstico molecular dispensam o cultivo e são exequíveis quando as bactérias estão inviáveis ou em amostras multicontaminadas. Métodos moleculares convencionais (PCR, qPCR, Nested-PCR) requerem equipamentos sofisticados para amplificação e visualização dos resultados, impedindo seu uso em laboratórios menos equipados. A amplificação isotérmica mediada por loop (Loop-mediated isothermal amplification - LAMP), uma variação da PCR convencional, utiliza enzima que permite amplificação isotérmica, apresenta alta especificidade, sensibilidade, rapidez e custo reduzido, sendo utilizada na detecção de diversos patógenos. Esta técnica emprega de quatro a seis primers e a enzima Bst DNA polimerase, que além da atividade de síntese, atua abrindo a fita dupla de DNA. O resultado da amplificação é visualizado no próprio tubo, a olho nu. O objetivo deste projeto foi aplicar a técnica LAMP no desenvolvimento de um teste para o diagnóstico da peste. Foram construídos cinco primers específicos para amplificação do gene caf1, exclusivo de Y. pestis, utilizados em ensaios com o DNA da cepa Y. pestis A1122, para determinar as concentrações ótimas dos reagentes, temperatura de incubação (60°C, 63°C e 65°C) e tempo de duração da reação (15, 30, 45, 60 e 90 minutos). As reações foram incubadas em banho maria. A amplificação foi visualizada diretamente nos tubos contendo SYBR® Safe ou SYBR® Green I. Foi observado que a partir de 45 minutos de reação ocorre amplificação do gene caf1, nas três temperaturas testadas. Além disso, a técnica mostrou-se específica e sensível, detectando até 10 pg de DNA de Y. pestis.

Submicron polymer particles containing fluorescent semiconductor nanocrystals CdSe/ZnS for bioassays.

AIM: This study aimed to design a panel of uniform particulate biochemical reagents and to test them in specific bioassays. These reagents are polymer particles of different sizes doped with semiconductor nanocrystals and conjugated with either full-size antibodies or recombinant mini-antibodies (4D5 scFv fragment) designed by genetic engineering approaches. MATERIALS & METHODS: A panel of highly fluorescent polymer particles (150-800 nm) were formed by embedding CdSe/ZnS nanocrystals (quantum dots) into preformed polyacrolein and poly(acrolein-co-styrene) particles. Morphology, content and fluorescence characteristics of the prepared materials were studied by laser correlation spectroscopy, spectrophotometry, optical and fluorescent microscopy and fluorimetry. RESULTS: The obtained fluorescent particles sensitized by anti-Yersinia pestis antibodies were used for rapid agglutination glass test suitable for screening analysis of Y. pestis antigen and for microtiter particle agglutination, which, owing to its speed and simplicity, is very beneficial for diagnostic detection of Y. pestis antigen. Recombinant 4D5 scFv antibodies designed and conjugated with polymer particles containing quantum dots provide multipoint highly specific binding with cancer marker HER2/neu on the surface of SKOV-3 cell.

Role of the Yersinia pestis yersiniabactin iron acquisition system in the incidence of flea-borne plague.

Plague is a flea-borne zoonosis caused by the bacterium Yersinia pestis. Y. pestis mutants lacking the yersiniabactin (Ybt) siderophore-based iron transport system are avirulent when inoculated intradermally but fully virulent when inoculated intravenously in mice. Presumably, Ybt is required to provide sufficient iron at the peripheral injection site, suggesting that Ybt would be an essential virulence factor for flea-borne plague. Here, using a flea-to-mouse transmission model, we show that a Y. pestis strain lacking the Ybt system causes fatal plague at low incidence when transmitted by fleas. Bacteriology and histology analyses revealed that a Ybt-negative strain caused only primary septicemic plague and atypical bubonic plague instead of the typical bubonic form of disease. The results provide new evidence that primary septicemic plague is a distinct clinical entity and suggest that unusual forms of plague may be caused by atypical Y. pestis strains.

Distinct clones of Yersinia pestis caused the black death.

From AD 1347 to AD 1353, the Black Death killed tens of millions of people in Europe, leaving misery and devastation in its wake, with successive epidemics ravaging the continent until the 18(th) century. The etiology of this disease has remained highly controversial, ranging from claims based on genetics and the historical descriptions of symptoms that it was caused by Yersinia pestis to conclusions that it must have been caused by other pathogens. It has also been disputed whether plague had the same etiology in northern and southern Europe. Here we identified DNA and protein signatures specific for Y. pestis in human skeletons from mass graves in northern, central and southern Europe that were associated archaeologically with the Black Death and subsequent resurgences. We confirm that Y. pestis caused the Black Death and later epidemics on the entire European continent over the course of four centuries. Furthermore, on the basis of 17 single nucleotide polymorphisms plus the absence of a deletion in glpD gene, our aDNA results identified two previously unknown but related clades of Y. pestis associated with distinct medieval mass graves. These findings suggest that plague was imported to Europe on two or more occasions, each following a distinct route. These two clades are ancestral to modern isolates of Y. pestis biovars Orientalis and Medievalis. Our results clarify the etiology of the Black Death and provide a paradigm for a detailed historical reconstruction of the infection routes followed by this disease.

Contribuição para o diagnóstico de peste / Contribution towards plague diagnosis

Apesar de sua fundamentação clínico-epidemiológica, numerosos casos suspeitos de peste nos focos brasileiros têm sido descartados por serem negativos pelo teste de hemaglutinação para detecção de anticorpos contra o antígeno F1 da Yersinia pestis. A transcendência da peste justifica estudar se tais resultados decorrem da falta de resposta ao F1, e se outras proteínas da Yersinia pestis poderiam ser reconhecidas nos soros suspeitos, sendo desta forma candidatas como alvo diagnóstico alternativo ao F1. Assim sendo, cepas de Yersinia pestis e de Yersinia pseudotuberculosis, uma proteína YopH recombinante e a F1 foram utilizadas para analisar soros de pacientes e soros imunes de coelhos. A F1 e a YopH não foram reconhecidas pelos soros humanos HA- e nenhuma proteína majoritária, comum a todos os soros humanos e coelhos, foi identificada, o que permite concluir que os casos suspeitos devem ser submetidos a uma avaliação clínico-laboratorial mais rigorosa, aprofundando a investigação epidemiológica em busca de outras etiologias.

Despite the clinical-epidemiological features of plague, numerous suspected cases in Brazilian outbreaks have been discarded because of negative results from the hemagglutination test for antibodies against the Yersinia pestis F1 antigen. The transcendence of plague justifies studying whether such results are due to unresponsiveness to F1, and whether other Y. pestis proteins might be recognized in suspect serum. These would therefore be candidates to be alternative diagnostic targets to the F1 antigen. Thus, strains of Y. pestis and Y. pseudotuberculosis, a recombinant YopH protein and the F1 antigen were used to analyze serum from patients and immune serum from rabbits. F1 and YopH were not recognized by HA-negative human serum and no major protein common to all the human and rabbit serum samples was identified. This allows the conclusion that suspected cases must be subjected to more rigorous clinical-laboratory evaluation, with strengthening of epidemiological investigations in the search of other etiologies.

[Study on an epidemic of human lung plaque in Nangqian county, Qinghai province].

OBJECTIVE: To study an epidemic of human lung plague fulminant from September to October, 2004 in Nangqian county, Qinghai province. METHODS: Cases were diagnosed through data from epidemiological, clinical, bacteriological, serological and autopsy studies. RESULTS: 14 patients were identified, ending up with 6 deaths and 8 cured. The first case was diagnosed as primary pesticemia late progressed to lung plague. 4 cases were transformed from pesticemia out of 13, leaving the 9 cases as primary lung plague. Situation was under complete control through routinely handling the plague focus. CONCLUSION: The first case was bitten by the infected fleas which parasitized the marmota preyed on a dog but later these fleas were brought into the tent by the dog. The others cases were infected through droplets or dust. Programs on monitoring and controling the amount of marmotas and fleas should to be strengthened to prevent the epidemics of plague in the area.

Avaliação da técnica Nested-PCRTbU para aplicação no diagnóstico da peste / Evaluation of Nested-PCRTbU technique for application in the diagnose of pestis

O diagnóstico de certeza da peste baseia-se na identificação e isolamento da Y. pestis pelo cultivo de material de pacientes humanos, de roedores e suas pulgas. No Brasil, os casos humanos e as epizootias de peste ocorrem em locais distantes dos centros de diagnóstico. A competição com a flora cadavérica das carcaças de roedores e procedimentos inadequados de conservação e transporte das amostras aos laboratórios pode resultar na morte do bacilo e resultados falso-negativos. As técnicas moleculares apresentam-se como alternativas para estas situações, particularmente técnicas baseadas em PCR. No presente trabalho foi otimizada para o diagnóstico da peste a técnica N-PCRTbU que se baseia na separação física dos primers por imobilização dos primers internos na tampa do microtubo, dispensando a abertura do mesmo entre as duas etapas de amplificação, o que reduz a possibilidade de falsopositivos pela contaminação cruzada durante a manipulação dos amplicons no Nested-PCR convencional. Dois pares de primers, dirigidos ao gene estrutural (caf1) do antígeno F1 de Y. pestis (um par com homologia a uma região mais externa ao alvo e outro com homologia a uma região mais interna), foram inicialmente testados individualmente por PCR e depois por N-PCR tendo sido obtidos segmentos de tamanho esperado. Foram estabelecidas as concentrações de Taq DNA polimerase, dNTPs e MgCl2, bem como a proporção entre os primers externos e internos para o N-PCRTbU. Nos ensaios para estabelecimento do limiar de detecção a partir de DNA total e da cultura da cepa Y. pestis P. PB 881 a N-PCRTbU foi capaz de detectar respectivamente 10 pg de DNA e 20 bactérias viáveis. Baços de camundongos "Swiss Webster" infectados experimentalmente com a cepa Y. pestis P. PB 881 e amostras de baço, fígado, pulmão e coração conservadas no meio de Cary-Blair por 11 meses foram analisadas em paralelo por cultivo em gelose peptonada e pela técnica NPCRTbU. O fragmento de tamanho esperado (460pb) foi amplificado em todas as amostras mesmo nas que se revelaram multicontaminadas ou negativas pela cultura. Nos ensaios com DNA de outras espécies do gênero Yersinia: Y. pseudotuberculosis e Y. enterocolitica e com baços de camundongos não infectados com a Y. pestis não houve amplificação. Além da especificidade e sensibilidade, como os resultados podem ser obtidos rapidamente, em menos de 24 horas, a N-PCRTbU poderá ser mais uma opção em situações emergenciais [...]

Imported plague--New York City, 2002.

On November 1, 2002, a married couple traveled from Santa Fe County, New Mexico, to New York City (NYC), where they both became ill with fever and unilateral inguinal adenopathy; bubonic plague (Yersinia pestis) was diagnosed subsequently. This report summarizes the clinical and public health investigation of these cases and underscores the importance of rapid diagnosis and communication among health-care providers, public health agencies, and the public when patients seek medical attention for an illness that might be caused by an agent of terrorism.

Planning for biological disasters. Occupational health nurses as "first responders".

1. As a result of recent terrorist events, there is an immediate need for occupational nurses to review their disaster plans and to develop strategies to cope with bioterrorism in their workplaces. 2. The Centers for Disease Control and Prevention has identified three major categories of biological weapons. Category A, which is the highest priority category (and the focus of this article), includes smallpox, anthrax, botulism, plague, tularemia, filoviruses, and adenoviruses. Dealing with bioterrorism requires occupational health nurses to be familiar with these organisms, including their pathophysiology and methods of prevention, detection, and treatment. 3. Five principles can be used to guide responses to a biological attack. Incorporation of these principles into disaster planning will increase the effectiveness of responses to bioterrorism, if and when it occurs. Developing a plan of action before an event occurs will greatly enhance the likelihood that the repercussions of such an event are minimized.

The use of filter paper plasticized with polyvinyl alcohol-glutaraldehyde in ELISA

F1-antigen purified from Yersinia pestis was covalently linked to 5-mm diameter filter paper discs plasticized with polyvinyl alcohol-glutaraldehyde. These discs were used both for ELISA and dot-ELISA for the detection of anti-F1 IgG in rabbits. The best conditions were achieved using 1.25 µg of F1 antigen/disc, 3 percent w/v skim milk in PBS as blocking agent, anti-IgG peroxidase conjugate diluted 12,000 times, and serum from rabbits immunized or not against Y. pestis, diluted 6,400 times. The absorbance values obtained from the comparative study between this procedure and conventional ELISA were not significantly different but the low cost of the reagents employed in ELISA using the filter paper discs plasticized with polyvinyl alcohol-glutaraldehyde makes this method economically attractive.