Epidemiological trend of human leptospirosis in Italy between 1994 and 1996

In the three-year period 1994–1996, 222 reports on human cases of leptospirosis were received by the Italian Ministry of Health. The average annual number of reports was 29.2% lower than in the preceding eight years. In all cases but two the infections were thought to have been acquired in Italy. As in previous years, the majority of cases was observed in the northern regions of the country (83.8%), mostly in males (88.9%). Cases occurred in all age groups, but were more common in the working-age population (15–64 years). There was no common-source outbreaks. The typical leptospiral seasonal course, with a peak in August, was observed. During 1994, leptospirosis was the reported cause of death in 19 patients. Mortality was higher among males than females. The overall fatality rate was 22.6%. During the study period, a total of 126 cases of leptospirosis were confirmed by the National Centre for Leptospirosis or one of the 12 Regional Leptospira Laboratories. Of the 103 patients for whom information on place of residence, contact with animals, occupational and recreational activities was available, 98 (95.1%) were people who live in rural areas or devote themselves to occupational or recreational activities at risk. The likely source of infection and the mode of exposure were known for 55 patients. Forty-five patients (81.8%) were likely infected by contaminating water (43 cases) or soil (2 cases), ten (18.2%) by direct contact with animals or animal urine. Both running (51.2%) and stagnant water (27.9%) have been reported as a source of infection. Rodents were implicated in 50.0% of the 10 cases involving animals. In comparison with the preceding eight-year period, the risk of contracting leptospirosis was found to have increased for recreational activities (from 34.7 to 38.2%) and decreased for occupational activities (from 45.8 to 32.7%). A large number of infections, however, was ascribed to accidental events (25.5%). As in the previous period, besides fever, the involvement of the liver was the most frequent clinical manifestation (70.8%). Influenza-like symptoms were the only signs of illness in 15.1% of cases. Infections by 9 different serogroups were detected. The most frequent antibodies were those against serovars icterohaemorrhagiae, poi, copenhageni and bratislava. The presence of co-agglutinins against serovars belonging to different serogroups prevented the identification of the presumptive infecting serogroup in 19.8% of subjects.     

Weil's disease, milker's fever and other leptospiroses, 1981-1987

In The Netherlands, human leptospirosis is mainly caused by the serovars icterohaemorrhagiae and copenhageni, both of which belong to the Icterohaemorrhagiae group and originate from rats, serovars hardjo from cattle and grippotyphosa from voles. In 1981-1987, 175 cases of leptospirosis were registered. In 17 of these cases the infection was acquired outside The Netherlands. Infections caused by serovars from the Icterohaemorrhagiae group were mainly observed in the province of Zuid-Holland, hardjo infections in the province of Friesland. The number of hardjo infections increased. Hardjo also causes problems in cattle. Infections caused by serovars icterohaemorrhagiae and copenhageni were mainly associated with exposure to inland surface waters in relation with recreational or professional activities or accidents. Hardjo infections were characteristically associated with dairy farming. The incidences of all types of leptospirosis were highest in late summer and early autumn.     

The changing epidemiology of leptospirosis in Israel.

We reviewed all serologically confirmed cases of leptospirosis from 1985 to 1999 in Israel, where the disease is endemic. There were 59 cases, with an average annual incidence of 0.05/100,000. The dominant serogroup, Leptospira icterohemorrhagica, occurred in 29% of patients; in an earlier study (1970-1979), it accounted for only 2%. Serogroups that occurred mainly in rural areas accounted previously for 79% but had declined to 32%.     

Survey on the prevalence of leptospira infections in the Italian population

This investigation is the first nationwide survey on the circulation of leptospira infections in human beings in Italy. In nine out of twenty Italian regions, representative samples of the population were investigated for the presence of leptospira infections. Unexpectedly, leptospira infections were found to be widespread, the number of cases being much higher than the diagnosed clinical cases. There were found to be high, medium, and low risk areas. On the whole, the risk for the rural population was no higher than the risk for urban dwellers; leisure activities, contact with animals and residence on the plain versus residence in the hills were important risk factors. There was an unidentified risk factor in urbanites which was absent in the rural population. A changing pattern in infecting serovars was observed, with infections from serogroups Sejroe, Javanica and Australis prevailing over infections from the Icterohaemorrhagiae and Bataviae serogroups, which were the main agents of human leptospirosis during the 1950s. The mechanisms of these changes, the need for epidemiological surveys and improved diagnostic methods of screening are discussed.     

A twelve-year study of leptospirosis on Barbados

Between November 1979 and December 1991, 398 cases of severe leptospirosis were confirmed on Barbados (range for 1980–1991 23–56; mean 32.7; incidence 13.3/100,000/year). For the six-year periods 1980–1985 and 1986–1991 there was no significant change in incidence with time. Incidence is unlikely to change significantly in the next decade. Monthly average case numbers ranged from 1.4 (July) to 4.3 (November). The average (2.8) for June to December (the 7 wetter months) was not significantly higher than that (2.5) for January to May (the 5 drier months). The age range was 7–86. There were three times as many male cases (302) as female (96), and nearly 10 times as many in those <35. Although the highest number of cases (69) was in males aged 15–24, the highest incidence was in the older age groups, particularly the male 65–74 year-olds, and the female 55–64 year-olds. Leptospirosis was the proven cause of death in 55 (13.8%) hospital patients (annual range 0–13, mean 4.5). Some of a further 39 fatalities might have been cases. Death from leptospirosis was nearly twice as common among the women as among the men. Only one patient under 20 years of age died.Leptospira were isolated and identified from 117 (29.4%) of the 398 sick patients. The infecting organisms werebim (serogroup Autumnalis — 75),copenhageni (Icterohaemorrhagiae — 26),arborea (Ballum — 14) andbajan (Australis — 2). These infecting serovars could not be distinguished clinically, but infection was milder in children than in adults. Despite its predominance in surveyed children, serogroup Panama was virtually absent in this study. Rainfall is the major factor affecting the distribution of cases; not surprisingly, sanitation workers and agricultural workers appear to be the groups at highest risk. The general lack of clear-cut risk factors reflects the ubiquity of leptospires in the environment and the fact that the disease is not entirely occupational.     

A survey of leptospirosis in febrile patients mainly from hospitals and clinics in Trinidad

Acute and convalescent sera were obtained from 202 febrile patients, most of whom were admitted to or attended hospitals or clinics in northern Trinidad during the 12 months from mid-February 1977 to mid-February 1978. Laboratory tests confirmed that 10 of the patients were suffering from current leptospirosis while another 54 had serological evidence of previous leptospiral infections.Antibodies to strains of the Icterohaemorrhagiae serogroup were most commonly found, followed by those to the Hebdomadis and Autumnalis serogroups.Isolates were obtained from the blood of two and the urine of three of the 10 current cases. Four of these strains were identified as belonging to copenhageni serovar of the Icterohaemorrhagiae serogroup and one to serovar brasiliensis of the Bataviae serogroup.Seven of the patients suffering from leptospirosis were males, all rural dwellers, and all except one under 20 years of age. Two of the three female patients were over 60 years old and were urban dwellers. It was not possible to identify the sources of infection with certainty, although dogs may have been responsible for three of the Icterohaemorrhagiae and one of the Canicola infections.Of the 192 patients who were not currently infected, serological evidence of previous infection was obtained in 31 (40%) males and 23 (21%) females and was most common among farmers and rural workers.     

Leptospirosis in Kolenchery, Kerala, India: Epidemiology, prevalent local serogroups and servoars and a new serovar

Leptospirosis is the most widespread zoonosis in the world. It is mostly an occupational disease especially in rural areas. Kolenchery is in the midlands of Kerala. The landscape consists of marshy land and dry land interspersed by rivulets and ponds. Irrigation of dry lands for cultivation during the summer months started in mid 1980s after the irrigation projects were commissioned. Cases of leptospirosis were rarely diagnosed in Kolenchery before 1987. Since then a yearly increase in incidence is observed. No major study on either epidemiology or clinical picture has been done on human leptospirosis in Kerala so far. The aim of this study was to define the major clinical presentations, epidemiology of the infection and demonstrate the predominant serogroups and serovars causing the illness in this limited geographical area. The study involves 976 cases of leptospirosis confirmed by culture and/or serological tests. Serogroups Autumnalis, Australis and Icterohaemorrhagiae were the commonest. Mortality rate was 5.32%. The increase in incidence is probably due to the geographical characteristics, continuous moisture of the soil due to irrigation in summer and year-round cultivation making food and cover available to host rodents. Close interaction of humans, animals, soil and water in this region make the spread of leptospirosis to humans easy. Confirmation of cases has been done by enzyme linked immunosorbent assay (ELISA) and/or microscopic agglutination test (MAT) and/or by culture. Serovar identification has been done in 21 cultures isolated from patients. One new serovar belonging to serogroup Australis has been identified from a patient and named serovar Australis bharathy.     

Human leptospirosis in Italy, 1986–1993

In the eight-year period 1986–1993, the Italian National Center for Leptospirosis and the Regional Leptospira Laboratories confirmed 312 cases of clinical leptospirosis by using the microscopic agglutination (MA) assay. The majority of cases was observed in Northern regions of the Country. Cases were reported in all age groups, but were most common in the working-age population. Of 312 cases, 291 (93.3%) occurred among males. The largest number of infections was ascribed to occupational activities (45.8%). The typical leptospiral seasonal course, with a peak during the summer, was observed. Involvement of the liver was the most frequent manifestation. Influenza-like symptoms were the only signs of illness in 11.1% of cases. Anti-leptospira antibodies, cross-reacting with two or more serovars, were found in 28.2% of sera. The most frequent serovar-specific antibodies were those againstpoi, icterohaemorrhagiae, bratislava, copenhageni andsejroe.     

Incidence of leptospirosis in a select population in Nepal

The geographic distribution of leptospirosis is widespread but no national surveillance program exists in Nepal to establish the incidence of leptospirosis or the disease burden. This study reports the incidence of symptomatic leptospirosis in military personnel participating in an efficacy study of a hepatitis E virus vaccine in Nepal. Among the 1566 study volunteers who completed follow-up, we evaluated 271 illnesses over 2.2 years for the presence of leptospira IgM antibodies by ELISA. Positive ELISA results were confirmed by the microscopic agglutination test. The annual incidence of disease was between 3.5 and 6.1 cases/1000. The prevalence of confirmed leptospirosis was 9% among hepatitis cases and 8% among febrile cases. The most reactive serovars were Bratislava, Autumnalis, Icterohaemorrhagiae, and Sejroe. Leptospirosis should be considered in the differential diagnosis of febrile illnesses and icteric syndromes in Nepal. Additional studies are needed to establish the broader distribution and the spectrum of disease in Nepal.     

安徽省皖南山区钩端螺旋体病流行菌群(型)更迭分析

目的 对安徽省皖南山区钩端螺旋体病(简称钩体病)流行菌群(型)更迭情况进行研究，掌握菌群动态，为甲体病防制提供科学依据。方法 分别采用细菌分离培养和显微凝集试验(MAT)对自然人群、病人、疑似病人及宿主动物进行病原学调查和血清学分析。结果：该地区自然人群及病人血清抗钩端螺旋体标体现以赛罗群棉兰型为主，其阳性率分别为34.13%和25.82%。结论：皖南山区流行菌群（型）与20世纪90年代相比出现更迭现象，从黑线姬鼠肾组织标本中新分离出赛罗群棉兰型钩体菌株，啮齿动物仍是该地区钩体病的主要宿主，水牛是棉兰型钩体病宿主之一。     

云南边疆钩端螺旋体的血清型分布及动态

本文对1958~1980年从云南边疆热带雨林地区分离的病人株钩端螺旋体400株进行了鉴定,从中发现了15个血清群、41个血清型,其中包括1个新群、17个新型。流感伤寒、色若、秋季和黄疸出血四群为主要群,七日热、明尼、巴达维亚、犬、爪哇、塔拉索夫——歇尔曼六群为次要群,其它群为少见群。另对钩体菌型地区分布特点、动态和多价菌苗的应用作了分析探讨。     

Prevalence of leptospirosis in man. Pilot survey

A survey on the prevalence of leptospirosis was performed on the population living in an area of central Italy. The size of the sample was calculated in order to provide significant results in the case of a prevalence of infection in not less than 1 % of the population.Results demonstrated an unexpectedly wide circulation of leptospirosis in the surveyed area, showing a prevalence rate of infection of 11.34% for people living in rural areas and 3:08% for people living in the main town. The highest prevalence of infection (17.44%) was found in people between 30 and 44 years of age, living in rural areas.Such a wide circulation of undiagnosed past leptospiral infections was attributed both to the prevalence of mild clinical cases of leptospirosis in humans and the lack of microbiological tests performed to differentiate current leptospirosis from other infectious illnesses. An unexpected persistence in sera of co-agglutinins towards non-pathogenic serovars of L. biflexa was also noticed in healthy people.Criteria were established for the extension of the survey on the prevalence of leptospirosis to cover larger areas by limiting sampling to the more exposed age groups and to areas representative of a larger land belt.Corresponding author.     

Leptospirosis in the Andaman Islands, India

Leptospirosis is an emerging zoonosis. In the Andaman Islands during the early twentieth century, it occurred in the penal settlements of the British India Administration, mostly as Weil's disease, an acute febrile illness with hepato-renal complications. It was caused by leptospires belonging to groups Akiamy A and Andamans A. After the 1930s nothing further is known regarding the disease until the late 1980s, when Andaman haemorrhagic fever (AHF), a mysterious illness with the majority of cases presenting pulmonary involvement, appeared. AHF was later identified as leptospirosis and severe pulmonary haemorrhage was shown for the first time as a complication of leptospirosis from India. Leptospirosis continues to occur in the Islands annually. It generally presents as two separate clinical syndromes: the hepato-renal form, and the pulmonary form, which is associated with high case fatality rates ranging from 10 to 15%. Infections are due to a variety of serovars, Valbuzzi being the commonest. Leptospira interrogans sensu stricto has been the predominant infecting species. Doxycycline has been shown to confer a beneficial effect in reducing the clinical illness and mortality during outbreaks. The history of leptospirosis in the Islands, its epidemiology, clinical spectrum, characteristics of the isolates and control are reviewed and discussed in this article.     

Leptospirosis in Franche-Comté (FRANCE): Clinical,biological, and therapeutic data

Objectives and method

We report the patient data in 77 cases of leptospirosis confirmed by PCR and/or serology (micro-agglutination), observed between 1994 and 2008 at the Besançon teaching hospital. Our aim was to compare the epidemiological, clinical, biological, and therapeutic characteristics of leptospirosis in the Franche-Comté region, to those reported in other regions.

Results

The median age was 42 years and 95% were male patients. Leptospirosis acquisition was likely related to aquatic leisure activities (50.6%), professional exposure (28.6%), building maintenance works (11.7%), or unknown (9.1%). Forty-eight cases were uncomplicated and 29 were severe presentations of leptospirosis. Among severe cases, eight patients had to be managed in an intensive care unit, and one patient died. L. grippotyphosa and L. icterohaemorrhagiae were the main serogroups involved. Age above 50 years and serogroup L. icterohaemorrhagiae were positively associated with clinical severity. The outcome was favorable for 15 patients treated with ceftriaxone for less than 7 days.

Conclusions

We recommended conducting clinical trials aiming at validating short courses of ceftriaxone to treat leptospirosis.     

Evaluation of an immunoenzimatic test (ELISA) for the diagnosis of leptospirosis in Italy

An enzyme-linked immunosorbent assay (ELISA) was assessed to detect in humans IgM and IgG against the main serogroups/serovars of Leptospira present in Italy. Sonicated antigens from strain Wijnberg, serogroups Icterohaemorrhagiae and Riccio 2, serogroup Australis, were used in ELISA and the results were compared to microagglutination test (MAT). IgM were confirmed to be the predominant class of antibodies; the total sensitivity obtained by Wijnberg/ELISA with the sera of patients infected by different serogroups was 81.5% in relation to MAT, better sensitivity was achieved by the use of Riccio 2/ELISA; no reaction occurred with the control sera. Cross-reactivity was noted with some sera of patients with Lyme disease (IgM) and with few sera of patients with autoimmune disease (IgM and IgG).To improve the sensitivity of the ELISA both antigens Wijnberg and Riccio 2 must be employed in the immunoenzimatic assay, since serogroup Australis must be considered as a new emerging serogroup causing human leptospirosis in our country.Corresponding author.     

安徽省肺出血型钩端螺旋体病北移现象调查与分析

目的　针对由黄疸出血群和犬群引起的肺出血型钩体病在我省的北移现象进行调查分析。方法　通过现场流行病学、血清学和病原学方法进行调查分析。结果　肺出血型钩体病主要发生在我省Ⅲ型地区的皖南 ,而 80年代以来 ,原本在Ⅲ型地区流行的主要流行菌群—黄疸出血群 ,开始在Ⅰ型地区和Ⅱ型地区出现 ,并于 90年代后造成局部地区肺出血型钩体病的爆发流行 ,病死率高。结论　肺出血型钩体病在我省出现了北移现象 ,江淮之间及沿淮流域发生了钩体菌群更迭     

洪雅县钩端螺旋体病流行特征分析

[目的]了解洪雅县钩端螺旋体病流行特征及防治效果。[方法]收集1964年至今洪雅县钩端螺旋体病的人群发病及死亡情况、血清学及病原学检测结果、免疫接种资料,将资料整理后导入SPSS11.5进行统计分析。[结果]洪雅县1964年至今各年均有钩体病发生,1964￣1993年期间年发病率波动在5.9￣290.1/10万之间(年均发病率56.3/10万)。1970￣1977年的流行高峰在每年的8￣10月,病人数占全年的88.6%,与水稻收割时间一致;人群分布以农民为主,占82.4%;年龄组以10￣39岁组为主,占88.5%。1979￣1980年,5种鼠(226只)肾组织培养钩体阳性率为5.3%,其中黑线姬鼠钩体阳性率为18.1%。1979￣1984年,132例患者血培养6例阳性(阳性率4.5%)。1979￣1985年,206例患者血清显凝试验,阳性率24.3%,收集86份阳性血清进行显凝试验:有黄疸出血群、秋季群、澳洲群等7个血清群。[结论]我县钩体病的流行趋势与全省流行趋势基本一致,主要流行菌群为黄疸出血群,钩体病疫苗接种对降低发病率有一定效果。     

Utility of phylogenetic studies in the identification of Leptospira strains

A phylogenetic tree, which distinguishes between the serovars and serogroups of leptospires common in Central Europe was constructed using an established RAPD procedure together with digital reading and evaluation (using different computer software programs) of the generated amplified DNA patterns. The application of this procedure has revealed a consistent correspondence between serogroup and genotype (position in constructed tree) in 69 cases, and serovar and genotype in 72 cases, of wild strains of leptospires. There was an agreement between serovar and genotype in cases of strains of Grippotyphosa, Pomona, Mozdok, Arborea and Sorexjalna as well as between serogroup and genotype in cases of Australis, Bataviae and Sejroe. With the procedure used in this study, it was not possible to distinguish between reference strains of serovars Jalna, Bratislava and Lora (all serogroup Australis) as well as between serovars Icterohaemorrhagiae and Copenhageni (both of serogroup Icterohaemorrhagiae). In contrast to this, wild strains belonging to serogroup Sejroe were distributed between Polonica, Istrica, Saxkoebing and Sejroe serovars. Endemic strains of leptospires tested, were also distinguishable.     

Seroepidemiological study of human leptospirosis at Reunion Island

In order to evaluate the prevalence of human leptospirosis in Reunion island and to identify possible risk factors, a study was realised on a representative population sample of 3.338 persons. The prevalence of leptospirosis, diagnosed by ELISA and confirmed by Micro Agglutination Test, was 1.1%. Male predominance and higher prevalence in rainy parts of the island, were confirmed. It has not been possible to display risk factors such as housing conditions or professional exercise. The serological repartition showed not only icterohaemorrhagiae serovar, but also canicola, panama and sejroe, especially in women. These results, compared with clinical studies (showing nearly exclusive male repartition, in agricultural workers, due to icterohaemorrhagiae serovar), confirm the double look of human leptospirosis in Reunion island: clinical leptospirosis, severe, concerning males, often countrymen, due to icterohaemorrhagiae serovar, and infraclinical leptospirosis, concerning principally females, which is a domestic illness, due to other serovars.     

Laboratory-acquired infections at the National Animal Disease Center 1960--1976

Experience with exposure to, or infection with pathogenic agents at the National Animal Disease Center is summarized. A total of 60 laboratory-associated exposures to infectious disease agents were reported. Forty-nine exposures resulted from known accidents, but the other 11 were identified only after the development of clinical or serological manifestations of infection. Eighteen cases of laboratory-acquired infections were reviewed. Brucellosis, the most frequently reported laboratory-acquired infection, accounted for one-half of the cases summarized. Three cases of leptospirosis, two cases of Newcastle disease, two cases of ringworm, and a single infection with Mycobacterium bovis and with Salmonella arizonae were also encountered. The most frequently reported causes of exposure were: auto-inoculation or spray exposure associated with the use of the hypodermic syringe, cuts or lacerations, direct contact with infected animals, and mouth pipetting. Although the infecting event could not be identified in 11 infections, presumptive evidence suggests aerogenic transmission as a probable route of exposure in a number of such cases.