Etiological structure of icterohemorrhagic leptospirosis in gray rats (Rattus norvegicus)

In 93 Leptospira strains isolated from Norwegian rats serovar determination was made. As a result, leptospires circulating among Norwegian rats were found to belong mainly to serovar copenhageni, group Icterohaemorrhagiae, while leptospires of serovar icterohaemorrhagiae, even if occurring, were found only in the animals inhabiting pigsties. Leptospirosis epizooty among rats, caused by L. icterohaemorrhagiae, took its course independently of leptospirosis epizooty among mice, caused by L. hebdomadis, and simultaneously with it.     

Leptospirotic etiology in pulmonary and upper respiratory tract pathology

A number of 3,200 febrile patients who presented upon admission to hospital primary pulmonary or upper respiratory tract impairment either as single forms of manifestation or associated to other syndromes were tested. The cases were screened by the rapid slide agglutination reaction with heat inactivated Patoc antigen and leptospirotic etiology was confirmed by the ultramicroscopic agglutination reaction with 18 live circulating pathogenic antigens. 64 leptospirosis cases with pulmonary impairment were confirmed and in 52 cases the upper respiratory tract was involved. Particular aspects of leptospirosis with pulmonary impairment: 71.8% of cases had a clinical diagnosis of interstitial pneumonia; 89% of cases presented important chest x-ray modifications; in an approximately equal number of cases the pulmonary involvement was the single manifestation or was associated with other syndromes; icterohaemorrhagiae, wolffi and pomona were the frequently encountered infecting serotypes. Particular aspects for leptospirosis involving the upper respiratory tract: 84.6% of cases had a clinical diagnosis of acute rhino-pharyngotracheitis; in 86.5% of cases the upper respiratory tract impairment was the single feature; the infecting serotypes were in decreasing order of frequency as follows: icterohaemorrhagiae, pomona, wolffi, canicola, grippotyphosa.     

ELISA for the detection of specific IgM and IgG in human leptospirosis

ELISA was used to detect specific IgM and IgG in sera from humans with current or past leptospirosis. A serological pattern of a high IgM titre (greater than or equal to 1280), or moderately increased IgM (160-640) in conjunction with a low IgG titre (less than or equal to 20), with serovar copenhageni antigen was characteristic for approximately two-thirds of the sera from serovar icterohaemorrhagiae patients obtained in the first two months of the disease. The antigen was the supernatant of a heated and centrifuged culture of leptospires. Antigens were prepared from serovars copenhageni, grippotyphosa, hardjo and patoc. Sera from patients with icterohaemorrhagiae, grippotyphosa and hardjo infections showed cross-reactivity when different antigens were used. In past infections the IgG titres were clearly higher with the homologous antigen. ELISA for IgM and IgG allows the rapid diagnosis of acute leptospirosis.     

Immunologic monitoring of leptospirosis in the Maritime Territory

The epidemiological and epizootic situation in Leptospira infections at the Maritime [correction of Primorski] Territory is evaluated on the basis of complex studies carried out in 1984-1989. As revealed in these studies, cases of leptospirosis among humans have a sporadic character and are mainly registered among professional high risk groups of the population. In the immunological structure of persons covered by the survey L. hebdomadis, L. pomona and L. javanica prevail. The anthropourgic foci of leptospirosis caused by L. pomona are of the leading epidemiological importance. Swine serves as the main source of infection in these foci. The study revealed the epidemic danger of the natural foci of leptospirosis caused by L. grippotyphosa and L. javanica in rice fields where the decisive factors of leptospirosis proved to be reed voles and striped field mice serving as reservoirs of this infection, as well as the synanthropic foci of leptospirosis caused by L. hebdomadis with house mice serving as the main carriers.     

The use of methanol extract of Leptospira interrogans in complement fixation tests for leptospirosis

Methanol extracts were obtained from L. interrogans serovars icterohaemorrhagiae and canicola and L. biflexa serovar patoc. Human sera from 167 normal individuals and 40 patients with different infectious diseases tested by complement fixation tests showed negative reactions. Sera from 100 patients with a suspicion of leptospirosis were tested by complement fixation tests and microscopic agglutination reactions. Agreement of 84% was found for those two reactions. Positive microscopic agglutination tests at a dilution 1:20-1:400 with negative complement fixation tests were observed in 5% of patients and negative microscopic agglutination with complement fixation tests in the range of 1:20-1:1280 were observed in 11% of the cases.     

Prevalence of Bacterial Febrile Illnesses in Children in Kilosa District,Tanzania

Introduction

Bacterial etiologies of non-malaria febrile illnesses have significantly become important due to high mortality and morbidity, particularly in children. Despite their importance, there are few reports on the epidemiology of these diseases in Tanzania, and the true burden of such illnesses remains unknown. This study aimed to identify the prevalence of leptospirosis, brucellosis, typhoid fever and urinary tract infections and their rate of co-infections with malaria.

Methods

A cross-sectional study was conducted at Kilosa district hospital in Tanzania for 6 months. Febrile children aged from 2–13 years were recruited from the outpatient department. Patients were screened by serological tests such as IgM and IgG ELISA, and microscopic agglutination test.

Results

A total of 370 patients were enrolled; of these 85 (23.0%) had malaria parasites, 43 (11.6%) had presumptive acute leptospirosis and 26/200 (13%) had confirmed leptospirosis. Presumptive acute brucellosis due to B. abortus was identified among 26 (7.0%) of patients while B. melitensis was detected in 57 (15.4%) of the enrolled patients. Presumptive typhoid fever due to S. Typhi was identified in thirty eight (10.3%) of the participants and 69 (18.6%) had urinary tract infections. Patients presented with similar symptoms; therefore, the identification of these diseases could not be done based on clinical ground alone. Co-infections between malaria and bacterial febrile illnesses were observed in 146 patients (39.5%). Although antibacterials and/or anti-malarials were prescribed in most patients, some patients did not receive the appropriate treatment.

Conclusion

The study has underscored the importance of febrile bacterial diseases including zoonoses such as leptospirosis and brucellosis in febrile children, and thus such illnesses should be considered by clinicians in the differential diagnoses of febrile diseases. However, access to diagnostic tests for discrimination of febrile illnesses is needed. This would allow febrile patients to receive the correct diagnoses and facilitation of accurate and prompt treatment.     

Rodent leptospirosis in Colorado

A study was conducted to evaluate leptospirosis in brown rats (Rattus norvegicus), muskrats (Ondatra zibethicus) and mice (Mus musculus) in southeastern Larimer County, Colorado. Leptospira serotype icterohaemorrhagiae was isolated from fourteen of 143 feral brown rats, an infection rate of 9.8%. Serological evidence of infection with this stereotype was found in 66.4% of the rats. Serological evidence of L. serotype ballum infection was present in three of 17 muskrats. Leptospires were seen in histological sections of kidney tissue from two of 61 feral mice. No isolations were made from cultures and serology was not done on mice.     

Rodents as the vectors of infective agents in the natural foci of infections in the Moscow megapolis

This work deals with the results of 40-year observations on the circulation of infective agents in the natural foci of infections (tularemia, leptospirosis, hemorrhagic fever with renal syndrome) among rodents and other small mammals in the territory of the Moscow. The monitoring of their frequency and the infection rates remains the main effective measure for the prophylaxis of dangerous infections among the population of the megapolis.     

Leptospirosis: an emerging global public health problem

Leptospirosis has been recognized as an emerging global public health problem because of its increasing incidence in both developing and developed countries. A number of leptospirosis outbreaks have occurred in the past few years in various places such as Nicaragua, Brazil and India. Some of these resulted due to natural calamities such as cyclone and floods. It is a direct zoonotic disease caused by spirochetes belonging to different pathogenic species of the genus Leptospira. Large number of animals acts as carriers or vectors. Human infection results from accidental contact with carrier animals or environment contaminated with leptospires. The primary source of leptospires is the excretor animal, from whose renal tubules leptospires are excreted into the environment with the animal urine. Majority of leptospiral infections are either sub clinical or result in very mild illness and recover without any complications. However, a small proportion develops various complications due to involvement of multiple organ systems. In such patients, the clinical presentation depends upon the predominant organs involved and the case fatality ratio could be about 40% or more. Febrile illness with icterus, splenomegaly and nephritis (known as Weil’s disease), acute febrile illness with severe muscle pain, febrile illness with pulmonary haemorrhages in the form of haemoptysis, jaundice with pulmonary haemorrhages, jaundice with heamaturea, meningitis with haemorrhages including sub conjunctival haemorrhage or febrile illness with cardiac arrhythmias with or without haemorrhages are some of the syndromes. Because of the protean manifestations of leptospirosis it is often misdiagnosed and under-reported. Although the basic principles of prevention such as source reduction, environmental sanitation, more hygienic work-related and personal practices etc., are same everywhere, there is no universal control method applicable to all epidemiological settings. Comprehensive understanding of the eco- epidemiological and cultural characteristics of a community that faces the problem of leptospirosis is an essential prerequisite for evolving an effective and acceptable control measure.     

Human leptospirosis caused by a new, antigenically unique Leptospira associated with a Rattus species reservoir in the Peruvian Amazon

As part of a prospective study of leptospirosis and biodiversity of Leptospira in the Peruvian Amazon, a new Leptospira species was isolated from humans with acute febrile illness. Field trapping identified this leptospire in peridomestic rats (Rattus norvegicus, six isolates; R. rattus, two isolates) obtained in urban, peri-urban, and rural areas of the Iquitos region. Novelty of this species was proven by serological typing, 16S ribosomal RNA gene sequencing, pulsed-field gel electrophoresis, and DNA-DNA hybridization analysis. We have named this species "Leptospira licerasiae" serovar Varillal, and have determined that it is phylogenetically related to, but genetically distinct from, other intermediate Leptospira such as L. fainei and L. inadai. The type strain is serovar Varillal strain VAR 010(T), which has been deposited into internationally accessible culture collections. By microscopic agglutination test, "Leptospira licerasiae" serovar Varillal was antigenically distinct from all known serogroups of Leptospira except for low level cross-reaction with rabbit anti-L. fainei serovar Hurstbridge at a titer of 1:100. LipL32, although not detectable by PCR, was detectable in "Leptospira licerasiae" serovar Varillal by both Southern blot hybridization and Western immunoblot, although on immunoblot, the predicted protein was significantly smaller (27 kDa) than that of L. interrogans and L. kirschneri (32 kDa). Isolation was rare from humans (2/45 Leptospira isolates from 881 febrile patients sampled), but high titers of MAT antibodies against "Leptospira licerasiae" serovar Varillal were common (30%) among patients fulfilling serological criteria for acute leptospirosis in the Iquitos region, and uncommon (7%) elsewhere in Peru. This new leptospiral species reflects Amazonian biodiversity and has evolved to become an important cause of leptospirosis in the Peruvian Amazon.     

Recombinant ligA for leptospirosis diagnosis and ligA among the Leptospira spp. clinical isolates

Rapid diagnosis for differentiation of leptospirosis from other pyrogenic infections prevailing in the same locality is imperative for proper treatment. During infection, the pathogenic Leptospira spp. express virulence factors which induce antibody responses in the infected host. In this study, 50 referenced Leptospira spp. belonging to six genomospecies and 10 L. interrogans clinical isolates were studied for the presence of a gene encoding an in vivo expressed, surface exposed, immunoglobulin-like protein, LigA, by using PCR and southern hybridization specific to the 5' terminus sequence of the DNA. LigA was also detected in the Leptospira spp. whole cell homogenates by a direct ELISA using a mouse antiserum to the C-terminal portion of recombinant LigA (cLigA) as a detection reagent. All pathogenic Leptospira spp. except one of the two strains of L. santorasai were positive for the gene and its phenotype while all of the L. borgpetersenii and L. biflexa strains were negative. Recombinant cLigA was used as an antigen in ELISAs for detecting IgM and IgG in the sera of leptospirosis patients and in the sera of patients with other febrile illnesses and healthy subjects. When acute phase sera were tested by the cLigA IgM- and IgG-ELISAs, 92% and 100% of the MAT-positive sera were positive, respectively. The diagnostic sensitivity was 100% when both IgM- and IgG-ELISAs were performed on the same acute phase sera and the results were combined. Acute and convalescence sera of patients who were Leptospira culture positive but MAT/IgM-dipstick negative gave 88% and 100% positives by combined cLigA IgM/IgG ELISAs. The diagnostic specificities for the cLigA IgM- and IgG-ELISAs were 98% and 100%, respectively. Our cLigA based-serology has a high potential for early diagnosis of leptospirosis especially when the culture and MAT results are not yet available.     

Towards the Burden of Human Leptospirosis: Duration of Acute Illness and Occurrence of Post-Leptospirosis Symptoms of Patients in The Netherlands

Background

Leptospirosis is a global zoonotic disease. Although important for the assessment of the burden of leptospirosis, data on the duration of the illness and the occurrence of post-leptospirosis complaints are not well documented. Hence the main objective of this study was to estimate the occurrence of persistent complaints and duration of hospital stay in laboratory confirmed leptospirosis patients in the Netherlands during 1985 to 2010. Additionally, several risk factors potentially impacting on the occurrence of post-leptospirosis complaints were investigated.

Methods/Principal Findings

The duration of the acute phase of leptospirosis was 16 days (IQR 12–23); 10 days (IQR 7–16) were spent hospitalized. Eighteen fatal cases were excluded from this analysis. Complaints of leptospirosis patients by passive case investigations (CPC) derived from files on ambulant consultations occurring one month after hospital discharge, revealed persistent complaints in 108 of 236 (45.8%) laboratory confirmed cases. Data on persistent complaints after acute leptospirosis (PCAC), assessed in 225 laboratory confirmed leptospirosis cases collected through questionnaires during 1985-1993, indicated 68 (30.2%) PCAC cases. Frequently reported complaints included (extreme) fatigue, myalgia, malaise, headache, and a weak physical condition. These complaints prolonged in 21.1% of the cases beyond 24 months after onset of disease. There was no association between post-leptospirosis complaints and hospitalization. However, individuals admitted at the intensive care unit (ICU) were twice as likely to have continuing complaints after discharge adjusting for age and dialysis (OR 2.0 95% CI 0.8-4.8). No significant association could be found between prolongation of complaints and infecting serogroup, although subgroup analysis suggest that infection with serogroups Sejroe (OR 4.8, 95%CI 0.9-27.0) and icterohaemorrhagiae (OR 2.0, 95%CI 0.9-4.3 CI) are more likely to result in CPC than infections with serogroup Grippotyphosa.

Conclusion/Significance

In addition to the acute disease, persistent complaints have an impact on the burden of leptospirosis.     

Epidemiological characterization of Ixodes tick-borne borreliosis in the Krasnoyarsk territory

The analysis of morbidity in tick-borne infections for many years indicates that in the 1960s-1990s in the total structure of the clinical forms of tick-borne encephalitis the erythematic form amounted to 1.4-20.9, which 1.9- to 3.1-fold exceeded the morbidity characteristics for the whole of Russia. The epidemiological analysis of morbidity at the territory for the period of 1992-2001 is indicative of the presence of the combined foci of tick-borne encephalitis and Ixodes tick-born borrelioses (TBB) in 42 regions of the territory. The cyclic character of morbidity and the irregularity of its spread in different regions of the territory can be observed. Among the TBB patients, town dwellers constitute, on the average, 75.8%. These tick-born infections exhibit regional differences connected with landscape variations and the patients age. However official statistics does not reflect the real epidemic situation at the territory: hypodiagnostics is primarily due to the absence of reliable laboratory confirmation in remote regions of the Krasnoyarsk territory.     

Epidemiologic situation in the quarantine of natural focal infections in the Southern Federal District

Materials on the situation in quarantine natural focal infections (anthrax, plague, tularemia, brucellosis, leptospirosis, etc.) in the Southern Federal District are presented. Experience in the provision of the epidemic safety in the above-mentioned diseases, based on the systematic surveillance on the activity of epizootological factors on the territory of the natural foci of infections, are described. The causes of the possible aggravation of the epidemiological situation in a number of nosological forms in connection with changes in natural and socio-economic factors are given. The results of the realization of regional programs, making it possible to improve the system interaction between the administrative territories, services and departments aimed at ensuring the epidemiological safety of the region, are shown.     

Unsuspected Leptospirosis Is a Cause of Acute Febrile Illness in Nicaragua

Background

Epidemic severe leptospirosis was recognized in Nicaragua in 1995, but unrecognized epidemic and endemic disease remains unstudied.

Methodology/Principal Findings

To determine the burden of and risk factors associated with symptomatic leptospirosis in Nicaragua, we prospectively studied patients presenting with fever at a large teaching hospital. Epidemiologic and clinical features were systematically recorded, and paired sera tested by IgM-ELISA to identify patients with probable and possible acute leptospirosis. Microscopic Agglutination Test and PCR were used to confirm acute leptospirosis. Among 704 patients with paired sera tested by MAT, 44 had acute leptospirosis. Patients with acute leptospirosis were more likely to present during rainy months and to report rural residence and fresh water exposure. The sensitivity of clinical impression and acute-phase IgM detected by ELISA were poor.

Conclusions/Significance

Leptospirosis is a common (6.3%) but unrecognized cause of acute febrile illness in Nicaragua. Rapid point-of-care tests to support early diagnosis and treatment as well as tests to support population-based studies to delineate the epidemiology, incidence, and clinical spectrum of leptospirosis, both ideally pathogen-based, are needed.     

Utility of the tourniquet test and the white blood cell count to differentiate dengue among acute febrile illnesses in the emergency room

Dengue often presents with non-specific clinical signs, and given the current paucity of accurate, rapid diagnostic laboratory tests, identifying easily obtainable bedside markers of dengue remains a priority. Previous studies in febrile Asian children have suggested that the combination of a positive tourniquet test (TT) and leucopenia can distinguish dengue from other febrile illnesses, but little data exists on the usefulness of these tests in adults or in the Americas. We evaluated the diagnostic accuracy of the TT and leucopenia (white blood cell count <5000/mm(3)) in identifying dengue as part of an acute febrile illness (AFI) surveillance study conducted in the Emergency Department of Saint Luke's Hospital in Ponce, Puerto Rico. From September to December 2009, 284 patients presenting to the ED with fever for 2-7 days and no identified source were enrolled. Participants were tested for influenza, dengue, leptospirosis and enteroviruses. Thirty-three (12%) patients were confirmed as having dengue; 2 had dengue co-infection with influenza and leptospirosis, respectively. An infectious etiology was determined for 141 others (136 influenza, 3 enterovirus, 2 urinary tract infections), and 110 patients had no infectious etiology identified. Fifty-two percent of laboratory-positive dengue cases had a positive TT versus 18% of patients without dengue (P<0.001), 87% of dengue cases compared to 28% of non-dengue cases had leucopenia (P<0.001). The presence of either a positive TT or leucopenia correctly identified 94% of dengue patients. The specificity and positive predictive values of these tests was significantly higher in the subset of patients without pandemic influenza A H1N1, suggesting improved discriminatory performance of these tests in the absence of concurrent dengue and influenza outbreaks. However, even during simultaneous AFI outbreaks, the absence of leucopenia combined with a negative tourniquet test may be useful to rule out dengue.     

Populations of pathogenic Leptospira of varying virulence in nature

The study of geographically remote populations of Norway rats (Rattus norvegicus) revealed that in one of these populations a highly virulent population of Leptospira copenhageni, serogroup icterohaemorrhagiae, and in another population of rats a faintly virulent population of these microorganisms circulated simultaneously. At the same time in vitro experiments with Leptospira cultures showed the absence of the constant probability of sharp changes in the level of their virulence in time.     

Etiological structure and clinical epidemiological characteristics of Leptospira infection in Rostov Province based on data from therapeutic institutions from 1960 to 1983

Changes in communal conditions, in economy, as well as in ecology and fauna, which took place in Rostov Province during the last decade (1973-1983) determined shifts in the etiological structure of Leptospira infection and in its course. The study revealed an increase in morbidity caused by L. icterohaemorrhagiae (up to 61%) and L. hebdomadis (up to 22%) with a simultaneous decrease in the isolation rate of L. grippotyphosa and L. pomona (up to 2-3%). In most cases (77%) the diseases caused by leptospires of different serogroups were found to take an icteric course accompanied by the development of hepatorenal insufficiency (46%). The similarity of clinical manifestations in different etiological forms of Leptospira infection was determined by common pathogenetic and pathophysiological features characteristic of the development of the leptospiral infectious process.     

Natural focus of leptospirosis in the rice paddies of Krasmodar Territory and the means for its eradication

OFFthe rice fields of the Krasnodar Territory the intensive epizootic of leptospirosis icterohemorrhagica can be observed in the population of Norway rats (995 animals have been examined and 102 cultures obtained) the whole year round. The highest intensity of the epizootic process is known to fall on the end of summer and the beginning of autumn (45-50% of Leptospira carriers). The natural focus of leptospirosis on the rice-growing complex is epidemiologically dangerous. The epizootic process can be suppressed by reducing the population of rats by means of poisoned baits. The alternate use of different poisons ( rotindan , brodifacum ) given in the form of paraffined briquettes has proved to be most expedient.     

Lipid metabolic changes in experimentally induced leptospiral infection with serovars australis, canicola and icterohaemorrhagiae

Changes in lipid fractions were evaluated in young guinea pigs when infected with 1 ml of 7 day old live cultures of leptospira interrogans serovars australis, canicola and icterohaemorrhagiae. Statistically significant elevation in triglycerides, very low density lipoprotein and phospholipid and a significant reduction in high density lipoprotein (HDL) in all the groups was observed. Cholesterol and low density lipoprotein showed ascending trend in icterohaemorrhagiae group, whereas they were normal in other groups. The results suggest that increase in triglycerides, phospholipid and decrease in HDL in a suspected case of leptospirosis may be considered as markers.