Histoid leprosy presenting as a large tumor

Abstract Histoid leprosy is a rare form of multibacillary leprosy, characterized by the presence of papules, plaques, or nodules whose appearance is keloid-like, skin colored, or erythematous. Fusiform cells are the main histopathological feature. Due to the fact that it can simulate other dermatological lesions, for example, dermatofibroma and neurofibroma, it constitutes a diagnostic challenge for clinicians and pathologists. It is a bacilliferous form of leprosy, and it plays an important role in disease transmission. A case of a patient with histoid leprosy living in the Northeast Region of Brazil is reported.

Histoid leprosy presenting as a large tumor.

Histoid leprosy is a rare form of multibacillary leprosy, characterized by the presence of papules, plaques, or nodules whose appearance is keloid-like, skin colored, or erythematous. Fusiform cells are the main histopathological feature. Due to the fact that it can simulate other dermatological lesions, for example, dermatofibroma and neurofibroma, it constitutes a diagnostic challenge for clinicians and pathologists. It is a bacilliferous form of leprosy, and it plays an important role in disease transmission. A case of a patient with histoid leprosy living in the Northeast Region of Brazil is reported.

Histoid leprosy - A rare clinical presentation.

Histoid leprosy is considered a rare form of lepromatous leprosy. Its peculiar clinical picture makes its diagnosis a challenging one, which can delay starting treatment and perpetuate the disease as endemic. In addition to representing a reservoir of bacilli, and being an important means of contamination, these patients have greater resistance to standard treatment. This is a report of a typical case of this rare presentation, aiming to share the knowledge and favor earlier diagnosis of the disease.

Case for diagnosis. Infiltrated areas on the trunk

Abstract Leprosy is an infectious disease with chronic evolution, caused by Mycobacterium leprae, an acid-fast bacillus that mainly affects the skin and peripheral nervous tissue. Many of the clinical manifestations of leprosy can mimic connective tissue diseases. The authors present the case of a 49-year-old woman who had been treated for four years for systemic lupus erythematosus in a rheumatological service. Skin biopsy of a plaque on the inguinal region was compatible with borderline lepromatous leprosy associated with a type 1 lepra reaction. The patient is undergoing treatment with multibacillary multidrug therapy, showing clinical improvement.

Case for diagnosis. Infiltrated areas on the trunk.

Leprosy is an infectious disease with chronic evolution, caused by Mycobacterium leprae, an acid-fast bacillus that mainly affects the skin and peripheral nervous tissue. Many of the clinical manifestations of leprosy can mimic connective tissue diseases. The authors present the case of a 49-year-old woman who had been treated for four years for systemic lupus erythematosus in a rheumatological service. Skin biopsy of a plaque on the inguinal region was compatible with borderline lepromatous leprosy associated with a type 1 lepra reaction. The patient is undergoing treatment with multibacillary multidrug therapy, showing clinical improvement.

Lepra en la isla colombiana de Providencia / Leprosy in the Colombian island of Providencia

San Andrés y Providencia son islas colombianas en el mar de las Antillas. San Andrés tiene 68.283 habitantes y allí se han registrado casos de lepra en inmigrantes provenientes del interior colombiano. Providencia tiene 5.037 habitantes e, históricamente, los programas de salud no tenían registros de la enfermedad; no obstante, en el 2009 se confirmaron dos casos de lepra multibacilar histioide y, posteriormente, otros dos, lo cual representa una prevalencia de 8 casos por 10.000 habitantes y la convierte en un sitio hiperendémico para lepra. Inicialmente, se diagnosticó lepra histioide en una niña de 14 años y, durante su estudio, se encontró la misma forma clínica de la enfermedad en su padre. Recientemente, se detectó lepra multibacilar en otro miembro de la misma familia y, lepra indeterminada, en una niña de otro núcleo familiar. El objetivo de este trabajo fue presentar estos casos clínicos ante la comunidad científica y los entes de salud pública, y llamar la atención de las autoridades de salud sobre la necesidad de establecer programas de vigilancia epidemiológica continua en la isla, incorporando las nuevas herramientas disponibles en el Programa de Control de la Lepra.

San Andrés and Providencia are Colombian islands in the Caribbean Sea. San Andrés has 68,283 inhabitants and has registered cases of leprosy in immigrants from continental Colombia. Providencia has 5,037 inhabitants and historically health programs did not have records of the disease, but in 2009 two cases of multibacillary histoid leprosy were confirmed and, subsequently, another two, which represents a prevalence of 8 cases per 10,000 inhabitants and places the island as a hyperendemic site for leprosy. Initially, a 14-year-old girl with histoid leprosy was diagnosed and, exploring this case, her father was diagnosed with the same clinical form of leprosy. Recently, a new intrafamilial patient with multibacillary leprosy and an extrafamilial case of a girl with undetermined leprosy were detected. The objective of this study was to present to the scientific community and the public health officers these clinical cases and to draw the attention of the sanitary authorities on the necessity of establishing continuous programs of leprosy epidemiological surveillance on the island using the new tools available in the Programa de Control de la Lepra (Leprosy Control Program).

Células gigantes en lepra lepromatosa: dermatitis difusa con células gigantes exuberantes de tipo cuerpo extraño en lepra lepromatosa tratada / Giant cells lepromatous leprosy: Diffuse dermatitis with exuberant foreign body giant cells in treated lepromatous leprosy

Resumen Los pacientes con lepra lepromatosa que han recibido tratamiento durante años, usualmente requieren seguimiento con biopsias de piel para detectar lesiones persistentes o si la baciloscopia es positiva, incluso si los valores son menores que los iniciales. Se presenta el caso de una mujer de 48 años de edad con lepra lepromatosa de 15 años de evolución, índice bacilar de 4 en el extendido directo y en la biopsia, que recibió tratamiento con múltiples medicamentos durante 32 meses, aunque lo recomendado por la Organización Mundial de la Salud (OMS) es una duración de 12 meses. Se tomó una biopsia de piel para determinar si la enfermedad estaba activa. Se observó inflamación dérmica difusa con numerosas células gigantes de tipo cuerpo extraño y macrófagos vacuolados (células de Virchow). Estas células, CD68 positivas, contenían material granular ácido-alcohol resistente positivo con inmunohistoquímica para BCG. Se encontraron bacilos fragmentados y el índice bacilar fue de 2. Se interpretó como una forma residual de lepra lepromatosa y se concluyó que la paciente no requería prolongar el tratamiento con múltiples medicamentos. Este perfil histológico se ha observado en casos similares, pero sin datos clínicos estas biopsias representan un reto diagnóstico. La acumulación de lípidos en estas células gigantes se debe a la destrucción bacilar y a la fusión de macrófagos vacuolados. Se revisó el papel de los lípidos del bacilo y del huésped en la patogenia de la lepra lepromatosa. En estos casos, no es necesario extender los 12 meses de tratamiento con múltiples medicamentos recomendados por la OMS. En el seguimiento de los pacientes, se recomienda contar con los hallazgos clínicos, la baciloscopia, la biopsia anual de piel y los títulos IgM antiglucolípido fenólico.

Abstract Patients with lepromatous leprosy that have received treatment for many years usually get follow up biopsies for persistent skin lesions or positive bacilloscopy even if the values are lower than in the initial bacilloscopy. We report the case of a 48-year old woman with long-standing lepromatous leprosy of 15 years of evolution, with a bacterial index of 4 in the direct smear and the initial skin biopsy. The patient was treated with multidrug therapy for 32 months although the treatment recommended by the World Health Organization (WHO) is only for 12 months. A skin biopsy was taken to determine if there was an active disease. We observed a diffuse dermal inflammation with numerous foreign body giant cells and vacuolated macrophages (Virchow´s cells). These cells contained granular acid-fast material that was also positive with immunohistochemistry for BCG. There were fragmented bacilli and the BI was 2. These cells were also strongly positive for CD68. The biopsy was interpreted as a residual form of lepromatous leprosy that did not require further multidrug therapy. We have observed similar histological profiles in several cases. The lack of clinical data makes it a histological challenge. The accumulation of lipids in these giant cells is due to bacillary destruction and fusion of vacuolated macrophages. We discuss here the role of bacillary and host lipids in the pathogenesis of lepromatous leprosy. We concluded that there was no need to extend the 12-month multidrug therapy recommended by WHO. Clinical findings, bacilloscopy, annual skin biopsy, and anti-phenolic glycolipid-I IgM titers are recommended procedures for the follow-up of these patients.

Erythroderma as a manifestation of leprosy

Abstract: Erythroderma consists of erythema and scaling involving most or all of the body surface. This generalized eruption may be idiopathic, drug-induced or secondary to cutaneous or systemic disease. A 71-year-old man is reported presenting generalized erythema and desquamation with deck-chair sign, nail dystrophy, and plantar ulcers associated with loss of local tactile sensitivity. Biopsies from three different sites demonstrated diffuse lymphocytic infiltrate with incipient granulomas. Fite-Faraco staining showed numerous isolated bacilli and globi. The skin smear was positive. Clinical and pathological diagnosis of borderline lepromatous leprosy was confirmed. This report demonstrates that chronic multibacillary leprosy can manifest as erythroderma and thus should be included in the differential diagnosis.

Epidemiological profile of leprosy reactions in a referral center in Campinas (SP), Brazil, 2010-2015

Abstract: Leprosy patients can present reactions during the course of the disease. There are no official data on these reactions in Brazil. We aimed to describe the epidemiological characteristics of patients with such reactions, analyzing information from patient records at a referral center in Campinas (SP), from 2010 to 2015.

Leg ulcer in lepromatous leprosy - Case report

Abstract: In Brazil, leprosy is a widespread infectious and contagious disease. Clinicians and specialists view leprosy broadly as a systemic infection, since, in its manifestations, it mimics many conditions, such as rheumatic, vascular, ENT, neurological and dermatological diseases. There are few studies that characterize the factors associated with ulcers in leprosy. These injuries should be prevented and treated promptly to avoid serious problems like secondary infections, sepsis, carcinomatous degeneration and amputations. We describe a patient with ulcers on his legs, involving late diagnosis of lepromatous leprosy.

Type 2 leprosy reaction with Sweet's syndrome-like presentation

Abstract Leprosy is a chronic disease characterized by manifestations in the peripheral nerves and skin. The course of the disease may be interrupted by acute phenomena called reactions. This article reports a peculiar case of type 2 leprosy reaction with Sweet's syndrome-like features as the first clinical manifestation of leprosy, resulting in a delay in the diagnosis due to unusual clinical presentation. The patient had clinical and histopathological features reminiscent of Sweet's syndrome associated with clusters of vacuolated histiocytes containing acid-fast bacilli isolated or forming globi. Herein, it is discussed how to recognize type 2 leprosy reaction with Sweet's syndrome features, the differential diagnosis with type 1 leprosy reaction and the treatment options. When this kind of reaction is the first clinical presentation of leprosy, the correct diagnosis might be not suspected clinically, and established only with histopathologic evaluation.

Leprosy in a University Hospital in Southern Brazil

AbstractBACKGROUND:Leprosy is an infectious disease that may lead to irreversible nerve damage, compromising patient's quality of life and leading to loss of working years.OBJECTIVES:To evaluate the epidemiological profile of patients followed at a University Hospital.MATERIALS AND METHODS: This is a retrospective observational study, based on a review of medical records. We studied the clinical and epidemiological features of patients with leprosy monitored at the Hospital de Clínicas of the Federal University of Paraná between January 2005 and January 2010.RESULTS:The mean age was 47.51, while 35.94% of patients were aged 41-60. The male:female rate was 1.8:1. The most prevalent occupations were: retired, students or rural workers. Patients came mainly from Curitiba or nearby areas, but there were also patients from the countryside. The mean diagnostic delay was 24.57 months. Multibacillary forms prevailed, with the lepromatous variety being the most common, closely followed by the borderline type. Neural enlargement was found in more than 50% of the patients and 48.44% of them developed reactional states. Hemolysis was the most commonly detected drug side effect. Initial functional evaluation was possible in 70% of patients, 55% of whom had disabilities upon diagnosis. The most prevalent associated disease was hypertension.CONCLUSIONS:This study showed an important diagnostic delay and a high rate of sequelae in this specific population. Brazil is one of the few remaining countries that has not yet eradicated leprosy and it is important to improve health policies in order to prevent sequelae and achieve eradication.

Hanseníase multibacilar em paciente transplantado renal: relato de caso / Multibacillary leprosy in a renal recipient patient: a case report

O Brasil é um país onde a hanseníase ainda é um problema de saúde pública, apresentando mais de 30.000 novos casos por ano nos últimos anos. Apesar do crescente número de transplante de órgãos sólidos realizados no país, sobretudo o transplante renal, não são frequentes os relatos dessa micobacteriose em pacientes imunossuprimidos pelas medicações póstransplante. Os autores relatam um caso de hanseníase multibacilar manifestada 12 anos depois do transplante renal, acompanhado desde o diagnóstico, durante a poliquimioterapia, tratamento e seguimento do eritema nodoso hansênico.

Leprosy is still a public health concern in Brazil, where more than 30,000 new cases are detected every year. There are few reports of this mycobacteriosis in imunossupressed pacients, despite the increasing number of solid organ transplantation and the use of post-transplant drugs in this country. The autors describe a case of multibacillary leprosy in a renal transplant recipient, detected 12 years after the procedure, and discuss the therapy, adverse effects and management of leprosy reactions in pacients imunosupressed by drugs.

Atypical lesions in relapsed leprosy

Relapsed cases of leprosy are not common in patients treated regularly with the recommended polychemotherapeutical schemes. Relapses must be readily identified and distinguished from reactions. This article reports a clinical case of relapse in leprosy, with atypical and exuberant skin changes in patient treated for eleven years with a paucibacillary scheme.

Hanseníase: pauci e multibacilares estão sendo diferentes? / Leprosy: are pauci and multibacillary being diferent?

Modelo do estudo: Estudo observacional descritivo transversal. Introdução: A estratégia atual de controle da hanseníase preconizada pela Organização Mundial da Saúde é baseada no respectivo tratamento segundo classificação operacional, se multibacilar ou paucibacilar. Objetivo: Comparar perfis de hansenianos de ambas as formas atendidos em Unidade Hospitalar. Metodologia: Coleta de dados em Fichas de Investigação de Hanseníase do Sistema de Informação de Agravos de Notificação, no Hospital e Maternidade Celso Pierro, PUC Campinas, anos 2007 a 2011. Registro em planilha codificada, armazenamento em banco de dados específico, e processamento estatístico por meio do SPSS. Associações de variáveis investigadas pela prova de Goodman para contraste entre e intra populações multinomiais e pelo teste não-paramétrico de Mann-Whitney, ao nível de 5% de significância. Resultados: Averiguaram-se 57 casos novos, obtendo-se 14 paucibacilares e 43 multibacilares com indicadores compatíveis com o esperado. No entanto, constataram-se, entre as inconsistências apuradas: i) cinco registros de recidiva, os quais não se confirmaram nosograficamente; ii) caso multibacilar tratado como paucibacilar; iii) quanto a modo de detecção, frequências assemelhadas de encaminhamento e demanda espontânea entre os multibacilares; iv) predomínio de grau zero de incapacidade entre paucibacilares, majoritariamente tuberculóides. Conclusões: Estes resultados indicam a necessidadede vigilância epidemiológica permanente visando à interlocução entre a rede básica e os centros de referência quanto aos procedimentos de controle, com vistas à adequação da gestão técnica dos respectivos Serviços de Saúde.

Study design: Cross sectional descriptive observational study. Introduction: Present strategy for leprosy control according to World Health Organization is based on respective treatment for pauci or multibacillary patients. Objectives: To compare leper’s profiles cared by an university hospital. Materials and Method: Data collected from Leprosy Notification Protocols, Information System for Notifiable Diseases, Celso Pierro Hospital and Maternity, PUC Campinas, years 2007 to 2011. Registers on codified sheets, storagein specific data base and statistical processing by SPSS program. Associations by Goodman’s test for contrasts among multinomial populations and by non-parametric Mann-Whitney’s, at 5% significance level. Results: 57 new cases have been ascertained, 14 paucibacillary and 43 multibacillary, showing clinical epidemiologic behaviors as expected. Nevertheless, inconsistencies have been observed, as: i) five cases of relapse registered, but not clinically confirmed; ii) a multibacillary case treated as paucibacillary; iii) in relation to forms of detection, similar frequencies of recommendation and spontaneous demand in the multibacillary group; iv) predominance of grade zero disabilities in the paucibacillary group. Conclusions: Results point to the necessity of permanent epidemiological surveillance on leprosy control in order to keep enough dialogue between basic units and reference centers.

Understanding the type 1 reactional state for early diagnosis and treatment: a way to avoid disability in leprosy / Compreender melhor o estado reacional tipo 1 para o diagnostico e tratamento precoces: uma forma de se evitar as incapacidades na hanseniase

A type 1 reaction or reversal reaction is expressed clinically by inflammatory exacerbation of the skin lesions and nerve trunks, consequently leading to sensory and motor alterations. It occurs in non-polar forms of leprosy, although it can occur in a small percentage of sub-polar LL treated patients. Disabilities, deformities and morbidity, still present in leprosy, are mainly caused by these acute episodes. The recognition of reactional states is imperative for an early approach and efficient management, to avoid the emergence of disabilities that stigmatize the disease. This review aims to describe the clinical aspects, immunopathogenesis, epidemiology, histopathological features and therapeutics of type 1 reactions.

A reação do tipo 1 ou reação reversa expressa-se clinicamente por uma exacerbação inflamatória das lesões de pele e de troncos nervosos, levando a alterações sensitivas e motoras. Ocorre nas formas não-polares da hanseníase, embora possa ocorrer numa pequena percentagem de pacientes LL tratados. As incapacidades físicas, deformidades e morbidade, ainda presentes na hanseníase, são causadas principalmente por esses episódios agudos. O reconhecimento dos estados reacionais é imperativo para uma abordagem precoce e manejo adequado, evitando a instalação de incapacidades que tanto estigmatizam a doença. Esta revisão tem como objetivo descrever aspectos clínicos, imunopatogênese, epidemiologia, características histopatológicas e terapêutica do estado reacional do tipo 1.

Descrição de um caso exuberante de eritema nodoso hansênico e análise crítica dos sistemas de classificação para tratamento da hanseníase / Description of a lush case of erythema nodosum and critical analysis of classification systems for the treatment of leprosy

A hanseníase é doença endêmica e de notificação compulsória no Brasil. Há diversos sistemas de classificação para instituição da poliquimioterapia. Descreve-se caso de jovem com diagnóstico e tratamento de hanseníase paucibacilar que, após sete anos, retorna com recidiva das lesões e tratamento para multibacilar, evoluindo com eritema nodoso necrotizante.

Leprosy is an endemic and notifiable disease in Brazil. There are several classification systems for institution of multidrug therapy. We describe the case of a young man with diagnosis and treatment of paucibacillary leprosy who, after seven years, returns with lesion recurrence and treatment for multibacillary evolving necrotizing erythema nodosum.

La lepra y el testículo / Leprosy and the testis

Introducción. La afección testicular es frecuente en la lepra lepromatosa, daño que se incrementa cuando cursa con eritema nudoso leproso. Objetivo. Presentar un paciente con lepra lepromatosa y eritema nudoso leproso con grave compromiso testicular. Materiales y métodos. Se estudió un hombre de 28 años con lepra lepromatosa desde los 22, que durante la poliquimioterapia para la lepra presentó eritema nudoso leproso crónico que afectó ambos testículos y no respondió al manejo convencional. El dolor persistente obligó a practicar orquidectomía izquierda. Resultados. Este testículo presentaba atrofia tubular y fibrosis notorias, conglomerados de macrófagos espumosos, sin bacilos, hiperplasia focal de células de Leydig, endarteritis y arteritis linfocitaria y granulomatosa de vasos pequeños y medianos; estos cambios también estaban presentes en el epidídimo. Un estudio llevado a cabo dos años después de terminar su tratamiento y de la orquidectomía izquierda, demostró azoospermia, testosterona total normal, testosterona libre discretamente disminuida y hormonas lutropina (luteinizante) y folitropina (estimulante del folículo) elevadas. No había disminución de la libido ni de su actividad sexual. Se revisaron los conceptos generales sobre el eritema nudoso leproso y las alteraciones que la lepra produce en el testículo. Conclusión. La lepra lepromatosa puede conducir a hipogonadismo. Los programas de lepra deben contemplar esta complicación para corregir y evitar sus secuelas.

Introduction. Damage of testicles is frequent in lepromatous leprosy and worsened by the presence of erythema nodosum leprosum. Objective. A patient is presented who developed lepromatous leprosy and erythema nodosum leprosum with major testicular compromise. Material and methods. The 28-year-old male patient had lepromatous leprosy since age 22. During a polychemotherapy treatment for the lepromatous leprosy, he presented chronic erythema nodosum leprosum that affected both testicles; he did not respond to the conventional treatment. A left orchidectomy was performed to treat the persistent pain. Results. The extracted testis evidenced the following: tubular atrophy, extensive fibrosis, cumulus of foamy macrophages without rods, focal Leydig cell hyperplasia, linfocitary and granulomatous arteritis and endarteritis of small and medium size vessels. These changes were also observed in the epididymis. Two years after the polychemoterapy and the orchidectomy, the patient exhibited azoospermy, normal total testosterone, slightly diminished free testosterone and elevated levels of luteinizing hormone and follicle-stimulating hormone. No loss of libido or sexual activity was reported. General concepts of erythema nodosum leprosum were reviewed, as well as the pathologic changes produced by leprosy in the testis. Conclusion. Lepromatous leprosy may lead to hypogonadism. This condition is recommended for inclusion in leprosy diagnostic programs in order to detect and treat the consequences of the possible hypogonadism.

Esquema alternativo para tratamento de hanseníase multibacilar em um caso de hepatotoxicidade durante a poliquimioterapia / Alternative treatment of multibacillary leprosy in a case of hepatotoxicity during multidrug therapy

A associação da dapsona, rifampicina e clofazimina tem se mostrado eficaz do tratamento da hanseníase multibacilar,entretanto a dapsona é responsável por inúmeros efeitos colaterais. Relata-se um caso de hepatoxocidade durante a poliquimioterapia, tratado com sucesso com a introdução de esquema alternativo com rifampicina,clofazimina e ofloxacino.

The combination of dapsone, rifampicin and clofazimine has proven quite effective in the treatment of multibacillary leprosy, however dapsone is responsible for numerous side effects. We report a case of hepatoxocidade during multidrug therapy, successfully treated with the introduction of alternative treatment with rifampicin,clofazimine and ofloxacin.

Lepra: enfermedad milenaria y actual / Leprosy: an ancient and present-day disease

El desconocimiento de la lepra es común en la población general al igual que entre los médicos y el personal de la salud. Se cree que esta enfermedad ya no existe; tal vez su imagen bíblica y milenaria refuerce la idea de su eliminación. Sin embargo, la lepra continúa siendo un problema de salud pública en varios países; entre los más afectados están India y Brasil. Después del inicio de la poliquimioterapia (PQT) en la novena década del siglo XX la prevalencia de la lepra disminuyó considerablemente pero no ocurrió lo mismo con la incidencia, lo que se atribuye al poco impacto de dicho tratamiento sobre el control de la transmisión y a la existencia de un reservorio aún no identificado con exactitud. Los convivientes de los leprosos tienen alto riesgo de sufrir la enfermedad en cualquier momento de la vida, pero hasta ahora no se ha podido determinar cuáles convivientes infectados desarrollarán la enfermedad. En Colombia se informan de 400 a 550 casos de lepra cada año, lo cual sugiere que la transmisión del Mycobacterium leprae continúa a pesar de que el país está considerado en la fase de poseliminación. Este artículo presenta una revisión histórica de la lepra desde los primeros informes disponibles hasta los avances moleculares más recientes. Incluye cómo ha evolucionado la comprensión de la enfermedad, su caracterización clínica, las medidas de control y saneamiento, el tratamiento y la epidemiología.

Ignorance about leprosy is common both in the general population and among physicians and health personnel. It is believed that this disease no longer exists. Perhaps its image as a biblic and ancient scourge reinforces the idea of its elimination. However, leprosy continues to be a public health problem in several countries; among the most affected are India and Brazil. After multidrug therapy (MDT) started during the ninth decade of the XX century prevalence of leprosy dramatically decreased. Incidence, however, did not follow the same trend, probably because of the low impact of MDT on transmission, and the existence of an as yet unidentified reservoir. Familial contacts of leprosy patients are at high risk of suffering the disease at any moment in their lives. So far it has not been possible to determine which ones of the infected contacts will develop the disease. Between 400 and 550 cases of leprosy are reported every year in Colombia. This fact suggests that transmission of Mycobacterium leprae still occurs despite the country being classified as in the postelimination phase. This article presents a historical review on leprosy from the earliest available reports to the more recent advances in the molecular understanding of the disease and its agent. It includes how the comprehension about it has evolved, its clinical characterization, public health control measures, therapy and epidemiology.