Epidemiology of human leptospirosis in urban and rural areas of Brazil, 2000-2015.

BACKGROUND: Leptospirosis is one of the most widespread zoonosis in the world and Brazil has the highest number of cases in Latin America. Transmission occurs mainly through exposure to water and soil contaminated by the urine of infected animals. The goals of this study are to describe the geographic distribution, demographic characteristics and exposure factors of urban and rural cases of leptospirosis, and identify spatial clusters in urban and rural areas of Brazil. METHODS/RESULTS: A retrospective epidemiological study was carried out using 16 years (2000-2015) of surveillance data from the Brazilian Ministry of Health. Cases were described by age, sex and race, and exposure factors were characterized in urban and rural areas. A spatial autocorrelation analysis was conducted using local Moran's I to identify urban and rural clusters of disease. On average 3,810 leptospirosis cases were reported annually with higher numbers in urban areas. National urban and rural incidence rates were the same (1.9 cases/100,000 population), however, regional differences were observed. Urban incidence rates were higher in the North and Northeast regions, while rural incidence rates were higher in the Southeast and South. The main exposure factor reported in urban and rural areas was exposure to places with signs of rodents, followed by flood in urban areas and agriculture and animal farming in rural areas. Clusters of leptospirosis were identified in densely populated urban areas of the North, Southeast and South regions, while rural clusters were concentrated in of the Southern region with large agriculture and animal farming practices. CONCLUSIONS: This study highlights that leptospirosis is an important public health problem in both urban and rural areas of Brazil. The results provide decision-makers with detailed information about where disease incidence is high and can be used in the development of prevention and control strategies for priority areas and risk groups.

An historical view of the experimental leptospiral infection in ruminants.

The first experimental infections with Leptospira in ruminants were conducted in the 1950s, primarily assessed the pathogenesis caused by serovar Pomona in cows. Throughout the decades, experimental infections have also demonstrated the clinical aspects of the infection by other strains, mainly Hardjo. Despite the important outcomes observed in experimental infections in ruminants, there is still a large discrepancy regarding the ideal dose, route, strain, model species or animal age that should be used to reproduce the acute and chronic leptospirosis in ruminants. In this context, the present study aimed to review the historical processes involved on the experimental leptospiral infection in ruminants. The inclusion criteria were papers that clearly described inoculation route, strain, dose, clinical signs and animal age. Overall, 37 experiments were noted. The most frequently reported clinical signs were fever, prostration, hematuria and death, with the majority of them occurring in young animals infected by incidental strains. Regarding reproductive problems, they occurred in the majority of the experiments and were also more related to incidental strains. In this context, abortions, retained placenta and weak fetuses were the most frequent symptoms. Noteworthy that although the mechanisms of the clinical acute disease either systemic or reproductive, is reasonably well understood, the physiopathology involved on reproductive problems due to the silent chronic infection is less discussed and remains to be elucidated. In this context, it is evident the need for studies focused on the genital infection and reproductive aspects of leptospiral infection in ruminants.

Leptospirosis in French Historical Medical Literature: Weil's Disease or Kelsch's Disease?

Early names for leptospirosis often indicate occupational or environmental exposure. Leptospirosis is hard to identify in the tropical setting because of co-circulating diseases. This is not the case in the temperate setting, such as Europe, where the few historical differential diagnoses were malaria, typhoid, and viral hepatitis. Leptospirosis presumably caused community epidemics in Europe before 1900 and military epidemiologists carefully documented outbreaks in "constrained settings." Achille Kelsch (1841-1911) synthesized available military data and epidemiological perspectives to define "epidemic jaundice" as a nosological continuum, caused by an infectious agent found in muds and water. He viewed Weil's disease as being only one form of that now well-identified disease continuum. The causative pathogen and epidemiological determinants were identified years later. The role of soils and muds as intermediate reservoirs, as suggested by Kelsch, deserves further investigation.

Mixed Leptospira Infections in a Diverse Reservoir Host Community, Madagascar, 2013-2015.

We identified mixed infections of pathogenic Leptospira in small mammals across a landscape-scale study area in Madagascar by using primers targeting different Leptospira spp. Using targeted primers increased prevalence estimates and evidence for transmission between endemic and invasive hosts. Future studies should assess rodentborne transmission of Leptospira to humans.

Leptospirosis among the self-supporting convicts of Andaman Island during the 1920s--the first report on pulmonary haemorrhage in leptospirosis?

Several researchers had carried out investigations on the possibility of existence of Weil's disease in Andaman Islands during early 20 th century. The first report of a series of confirmed cases of leptospirosis that occurred during 1929 was published in 1931.There were several reports during 1995 to 2009 that described detailed account of leptospirosis including various clinical syndromes. The possibility of pulmonary involvement in leptospirosis being a manifestation historically overlooked rather than newly emerged during the past two decades is examined in this review in the context of Andaman Islands. Two case series of leptospirosis, one occurred in 1929 and the other in 1996-1997 were reviewed with special emphasis on pulmonary involvement and haemorrhagic manifestations. The similarities and differences in the clinical profile of patients of the two case series were analysed. The review shows that respiratory system involvement and pulmonary haemorrhage as evidenced by presence of haemoptysis as a complication of leptospirosis was occurring during 1920s in Andaman Islands. The incidence of pulmonary involvement, however, rose from 9.4 per cent during 1929 to 52 per cent in 1996-1997. The case fatality ratio in patients with pulmonary involvement, which was 50 per cent during 1929 and 42.9 per cent during 1996-1997, was higher than that in cases without pulmonary involvement.Fever, conjunctival congestion, jaundice, vomiting, diarrhoea, hepatomagaly, haemoptysis, haematemesis and subconjunctival haemorrhage were common in both series. The case series in Andaman Islands in 1929 was probably the first report of pulmonary haemorrhage as a manifestation of leptospirosis. The increase in the incidence of pulmonary involvement in leptospirosis in the recent past is probably due to the increase in the density and diversity of its animal vectors,the broadening of the range of circulating serovars and the interactions between the vector and the agent. An increased virulence of Leptospira through gene acquisition and loss on an evolutionary time scale and the resulting change in the gene content, gene order and gene expression cannot be ruled out.

Leptospirose e seu aspecto ocupacional - Revisão de literatura / Leptospirosis and its occupational aspect - Literature review / Leptospirosis y su aspecto laboral - Revisión de literatura

A leptospirose é uma das zoonoses mais difundidas do mundo, no Brasil a doença é endêmica em todas as unidades da federação e epidêmica, principalmente, em períodos chuvosos. Sua ocorrência está relacionada às precárias condições de infraestrutura sanitária e alta infestação de roedores infectados. As inundações propiciam a disseminação do agente causal no ambiente, facilitando a eclosão de surtos. Nesta revisão de literatura objetivou-se mostrar o âmbito profissional/ocupacional que é de grande relevância para a saúde pública, atingindo diferentes categorias profissionais como agricultores, pecuaristas, biólogos, trabalhadores de arrozais, trabalhadores de saneamento ambiental, médicos veterinários, técnicos de laboratório, manipuladores de produtos de origem animal entre outras. Neste contexto, a leptospirose firma-se como uma doença de grande importância social e econômica, por apresentar elevada ocorrência, em determinadas áreas, alto custo hospitalar para o tratamento e ausência ao trabalho, como também por sua mortalidade Desta forma, faz necessária a intervenção dos gestores de saúde para redução dos índices desta enfermidade.

Leptospirosis is one of the most widespread zoonoses in the world. In Brazil, the disease is endemic in all Brazilian states and epidemic especially in the rainy periods, whose proliferation becomes favorable as a consequence of some environmental factors. Its occurrence is related to the poor sanitary infrastructure conditions and high infestation of infected rodents. Floods favor the spread of the causal agent in the environment, facilitating the emergence of outbreaks. This literature review aimed at showing the professional/occupational area that is of greatest importance to public health, affecting different professional categories such as farmers, ranchers, biologists, rice picking workers, environmental sanitation workers, veterinarians, laboratory technicians, handlers of animal products, among others. In this context, leptospirosis is considered a disease of great social and economic importance, due to its high incidence in certain areas, high hospital costs and loss of working days, as well as its lethality. Thus, the intervention of health managers is necessary to reduce the rates of this disease.

La leptospirosis es una de las zoonosis más extendidas en el mundo, en Brasil la enfermedad es endémica en todos los estados brasileños y epidémica, especialmente en períodos de lluvia. Su aparición está relacionada a las precarias condiciones de infraestructura de salud y de alta infestación de roedores infectados. Las inundaciones favorecen la propagación del agente causal en el entorno, facilitando la aparición de brotes. En esta revisión de literatura destinada a mostrar el área profesional / ocupacional que es de gran importancia para la salud pública, alcanzando diversas categorías profesionales como agricultores, ganaderos, biólogos, trabajadores de arrozales, trabajadores de saneamiento ambiental, veterinarios, técnicos de laboratorio, manipuladores de productos de origen animal, entre otros. En este contexto, la leptospirosis se hace una enfermedad de gran importancia social y económica, debido a su alta incidencia en determinadas zonas, los altos costos hospitalarios y pérdida de días de trabajo, así como por su mortalidad. Por lo tanto, se hace necesario la intervención de los administradores de salud para reducción de las tasas de esta enfermedad.

History of leptospirosis and leptospira.

Leptospira was isolated and identified as the causative agent of the severe human syndrome Weil's disease about 100 years ago almost simultaneously, but independently, by workers in Japan and Europe. Since that time leptospires have been isolated from almost all mammalian species on every continent except Antarctica, with leptospirosis now recognized as the most widespread zoonosis worldwide and also a major cause of disease in many domestic animal species. Recent advances in molecular taxonomy have facilitated the development of a rational classification system, while the availability of genome sequences and the development of mutagenesis systems have begun to shed light on mechanisms of pathogenesis that appear to be unique to Leptospira.

Leptospirosis-associated hospitalizations, United States, 1998-2009.

A small percentage of persons with leptospirosis, a reemerging zoonosis, experience severe complications that require hospitalization. The number of leptospirosis cases in the United States is unknown. Thus, to estimate the hospitalization rate for this disease, we analyzed US hospital discharge records for 1998-2009 for the total US population by using the Nationwide Inpatient Sample. During that time, the average annual rate of leptospirosis-associated hospitalizations was 0.6 hospitalizations/1,000,000 population. Leptospirosis-associated hospitalization rates were higher for persons >20 years of age and for male patients. For leptospirosis-associated hospitalizations, the average age of patients at admission was lower, the average length of stay for patients was longer, and hospital charges were higher than those for nonleptospirosis infectious disease-associated hospitalizations. Educating clinicians on the signs and symptoms of leptospirosis may result in earlier diagnosis and treatment and, thereby, reduced disease severity and hospitalization costs.

USDA regulatory guidelines and practices for veterinary Leptospira vaccine potency testing.

Batch-release potency testing of leptospiral vaccines licensed by the United States Department of Agriculture (USDA) historically was conducted through animal vaccination-challenge models. The hamster vaccination-challenge assay was Codified in 1974 for bacterins containing Leptospira pomona, Leptospira icterohaemorrhagiae, and Leptospira canicola, and in 1975 for bacterins containing Leptospira grippotyphosa. In brief, 10 hamsters are vaccinated with a specified dilution of bacterin. After a holding period, the vaccinated hamsters, as well as nonvaccinated controls, are challenged with virulent Leptospira and observed for mortality. Eighty percent of vaccinated hamsters must survive in the face of a valid challenge. The high cost of the Codified tests, in terms of monetary expense and animal welfare, prompted the Center for Veterinary Biologics (CVB) to develop ELISA alternatives for them. Potency tests for other serogroups, such as Leptospira hardjo-bovis, that do not have Codified requirements for potency testing continue to be examined on a case-by-case basis.

Human leptospirosis trends, the Netherlands, 1925-2008.

To increase knowledge of leptospirosis in the Netherlands and identify changing trends of this disease over time, we analyzed historical passive surveillance reports for an 84-year period (1925-2008). We found that 2,553 mainly severe leptospirosis cases were diagnosed (average annual incidence rate 0.25 cases/100,000 population). The overall case-fatality rate for patients with reported leptospirosis was 6.5% but decreased over the period, probably because of improved treatment. Ninety percent of reported leptospirosis cases were in male patients. Most autochthonous leptospirosis infections were associated with recreational exposures, but 15.5% of the cases were attributed to accidents that resulted in injury and to concomitant water contact. Since the end of the 1950s, the proportion of imported infections gradually increased, reaching 53.1% of the total during 2005-2008. Most (80.1%) imported infections were associated with sporting and adventurous vacation activities.

Ovine leptospirosis in Brazil

Leptospirosis is a zoonosis distributed worldwide, endemic mainly in humid subtropical and tropical countries, with epidemic potential. It affects a range of both wild and domestic animals, including sheep, which transport leptospires in their urine and, therefore, can infect other animals and humans who deal with them. Therefore, leptospirosis is characterized as an occupational zoonosis. In individual herds leptospirosis can cause severe economic loss due to miscarriages and outbreaks of mastitis with a significant reduction of milk production. The disease is caused by Leptospira interrogans, which was reclassified into 13 pathogenic species, and distributed into more than 260 serovars classified into 23 serogroups. The clinical signs of infection may vary depending on the serovar and host. In maintenance hosts, antibody production is generally low; there are relatively mild signs of the disease, and a prolonged carrier state with organisms in the kidneys. In incidental hosts, the disease may be more severe, with high titers of circulating antibodies and a very short or nonexistent renal carrier state. In general, young animals with renal and hepatic failure have more serious infections than adults. Several diseases may produce symptoms similar to those of leptospirosis, so that laboratory confirmation, through microscopic agglutination test, for example, is required. The effectiveness of treatment depends on early diagnosis and appropriate therapy, depending on clinical features, since leptospirosis can develop into chronic liver disease and nephropathy, progressing towards death. Improvements in habitation and sanitary conditions, rodent control, vaccination, isolation and treatment of affected animals are the main measures for the control of leptospirosis.

New hypothesis for cause of epidemic among native Americans, New England, 1616-1619.

In the years before English settlers established the Plymouth colony (1616-1619), most Native Americans living on the southeastern coast of present-day Massachusetts died from a mysterious disease. Classic explanations have included yellow fever, smallpox, and plague. Chickenpox and trichinosis are among more recent proposals. We suggest an additional candidate: leptospirosis complicated by Weil syndrome. Rodent reservoirs from European ships infected indigenous reservoirs and contaminated land and fresh water. Local ecology and high-risk quotidian practices of the native population favored exposure and were not shared by Europeans. Reduction of the population may have been incremental, episodic, and continuous; local customs continuously exposed this population to hyperendemic leptospiral infection over months or years, and only a fraction survived. Previous proposals do not adequately account for signature signs (epistaxis, jaundice) and do not consider customs that may have been instrumental to the near annihilation of Native Americans, which facilitated successful colonization of the Massachusetts Bay area.

Leptospirosis humana, una enfermedad olvidada / Human leptospirosis, a forget disease

En la historia de la humanidad se han descrito numerosas enfermedades que han influido negativamente sobre la supervivencia del hombre. Dentro de ellas, merece especial mención la leptospirosis, considerada históricamente la zoonosis de mayor repercusión internacional y que mayores daños ha provocado desde el punto de vista económico y social

Cerejeiras e cafezais: relações médico-científicas entre Brasil e Japão e a saga de Hideyo Noguchi / Cherry trees and coffee fields: medical and scientific relations between Brazil and Japan and the saga of Hideyo Noguchi

História dos sanitaristas da FSP/USP destaque nas páginas, 220-229, 297-299, 397, entre outras....

Leptospirosis in Germany, 1962-2003.

Epidemiologic trends of human leptospirosis in Germany were investigated by analyzing national surveillance data from 1962 to 2003 and by conducting a questionnaire-based survey from 1997 to 2000. After a steady decrease of leptospirosis incidence from 1962 to 1997, surveillance data indicate an increase in disease incidence to 0.06 per 100,000 (1998-2003). Of 102 laboratory-confirmed cases in humans from 1997 to 2000, 30% were related to occupational exposures. Recreational exposures were reported in 30% (including traveling abroad in 16%), whereas residential exposure accounted for 37% of the cases. Direct contact with animals, mostly rats and dogs, was observed in 31% of the cases. We conclude that recent changes in transmission patterns of leptospirosis, partially caused by an expanding rat population and the resurgence of canine leptospirosis, may facilitate the spread of the disease in temperate countries like Germany. Preventive measures should be adapted to the changing epidemiology of leptospirosis.