Leptospira Infection Research Articles

Occupational Risk Factors for Seropositive Leptospirosis among Town Service Workers in Northeastern Malaysia

Leptospirosis is speculated to be one of the most prevalent re-emerging zoonotic diseases to date, and town service workers are continuously exposed to occupational hazards that may increase their risk of infection. This study aimed to determine the occupational risk factors for leptospirosis among town service workers in northeastern Malaysia. A cross-sectional study was conducted among town service workers from four municipal councils. All sera samples were tested for the presence of anti-leptospiral antibodies using an enzyme-linked immunosorbent assay (ELISA) followed by a microscopic agglutination test (MAT). We found that 82 serum samples from 321 respondents were positive in the MAT (seroprevalence rate of 25.5%). Multiple logistic regression analysis identified overtime work (adj. OR 2.13; 95% CI 1.19, 3.84), contact with animals while working (adj. OR 2.09; 95% CI 1.06, 4.11), sighting of rats at the worksite (adj. OR 2.17; 95% CI 1.11, 4.25) and living less than 200 m from a river (adj. OR 1.84; 95% CI 1.03, 3.28) as risk factors for leptospiral infection. Whereas age (adj. OR 0.95; 95% CI 0.93, 0.98), wearing boots while working (adj. OR 0.44; 95% CI 0.25, 0.80) and washing hands with soap after work (adj. OR 0.20; 95% CI 0.10, 0.42) were recognised as protective factors. In conclusion, an association was observed between leptospirosis seropositivity among town service workers and the occupational factors. Prevention and control strategies for leptospirosis will require more focus on curbing the possible sources of leptospirosis transmission and maintaining safe work practices in high-risk working environments.

Infectious Uveitis in Horses and New Insights in Its Leptospiral Biofilm-Related Pathogenesis.

Uveitis is a sight-threatening eye disease in equids known worldwide that leads to considerable pain and suffering. By far the most common type of uveitis in Germany and neighboring countries is classical equine recurrent uveitis (ERU), which is caused by chronic intraocular leptospiral infection and is the main cause of infectious uveitis in horses. Other infectious causes are extremely rare and are usually clinically distinguishable from ERU. ERU can be treated very effectively by vitreous cavity lavage (vitrectomy). For proper indications of this demanding surgery, it is necessary to differentiate ERU from other types of uveitis in which vitrectomy is not helpful. This can be conducted on the basis of anamnesis in combination with ophthalmologic findings and by aqueous humor examination. During vitrectomy, vitreous material is obtained. These vitreous samples have historically been used for numerous etiologic studies. In this way, a chronic intraocular leptospiral infection has been shown to be the cause of typical ERU and, among other findings, ERU has also been recognized as a biofilm infection, providing new insights into the pathogenesis of ERU and explaining some thus far unexplainable phenomena of ERU. ERU may not only have transmissible aspects to some types of uveitis in humans but may also serve as a model for a spontaneously occurring biofilm infection. Vitreous material obtained during therapeutically indicated vitrectomy can be used for further studies on in vivo biofilm formation, biofilm composition and possible therapeutic approaches.

The association between natural drinking water sources and the emergence of zoonotic leptospirosis among grazing beef cattle herds during a human outbreak

Leptospirosis is a zoonotic bacterial disease associated with water abundance in tropical and temperate climate zones. Bacterial spread may also occur in dry and warm weather conditions when humans and animals are forced to share depleted water sources. In such settings, farm animals such as beef cattle, which may be present in large numbers in natural water sources, can play a major role in disease spread. However, the risk factors for their infection and the potential control measures to prevent the disease spread have not been adequately studied.In the face of an emerging human leptospirosis outbreak in the dry and warm Israeli 2018 summer, we tested seropositivity to Leptospira serovar Pomona in grazing beef cattle and wild boars located in proximity to the contaminated streams. Additionally, we used the natural setting of the outbreak to identify risk factors for seropositivity in beef cattle.We found high seropositivity to serovar Pomona in grazing beef cattle (233/845), and in wild boars (7/13). Seropositivity was significantly associated with beef cattle drinking from natural water sources compared to beef cattle drinking from water troughs with fresh water supply (Multivariable logistic regression; odds ratio = 18.6, 95% confidence interval = 3–116, p-value<0.01).One Health approach is necessary for mitigating zoonotic Leptospira infections, in which interactions between humans, animals, and the environment play a major role. As the global warming crisis results in severe climate changes, dry and warm weather conditions may become more common worldwide. Under such conditions, reducing inter-species interactions in contaminated natural water sources is essential for protecting public health. Our study demonstrates the role of natural water as a source for beef cattle infection and disease spread. Furthermore, we suggest using water troughs with freshwater supply for preventing future outbreaks in animals and humans in such settings.

A Three-Dimensional Lung Cell Model to Leptospira Virulence Investigations.

Leptospirosis is a worldwide zoonosis and a serious public health threat in tropical and subtropical areas. The etiologic agents of leptospirosis are pathogenic spirochetes from the genus Leptospira. In severe cases, patients develop a pulmonary hemorrhage that is associated with high fatality rates. Several animal models were established for leptospirosis studies, such as rodents, dogs, and monkeys. Although useful to study the relationship among Leptospira and its hosts, the animal models still exhibit economic and ethical limitation reasons and do not fully represent the human infection. As an attempt to bridge the gap between animal studies and clinical information from patients, we established a three-dimensional (3-D) human lung cell culture for Leptospira infection. We show that Leptospira is able to efficiently infect the cell lung spheroids and also to infiltrate in deeper areas of the cell aggregates. The ability to infect the 3-D lung cell aggregates was time-dependent. The 3-D spheroids infection occurred up to 120h in studies with two serovars, Canicola and Copenhageni. We standardized the number of bacteria in the initial inoculum for infection of the spheroids and we also propose two alternative culture media conditions. This new approach was validated by assessing the expression of three genes of Leptospira related to virulence and motility. The transcripts of these genes increased in both culture conditions, however, in higher rates and earlier times in the 3-D culture. We also assessed the production of chemokines by the 3-D spheroids before and after Leptospira infection, confirming induction of two of them, mainly in the 3-D spheroids. Chemokine CCL2 was expressed only in the 3-D cell culture. Increasing of this chemokine was observed previously in infected animal models. This new approach provides an opportunity to study the interaction of Leptospira with the human lung epithelium in vitro.

A retrospective study of acute kidney injury in dogs with renal resistive index as a prognostic indicator

Doppler ultrasonography is relatively a new method for evaluation of the renal diseases in dogs. This study was conducted to evaluate the efficacy of renal resistive index (RRI) in diagnosis and prognosis of acute kidney injury (AKI) in dogs and to ascertain its correlationwith other renal parameters. Twenty-seven dogs with AKI along with ten clinically healthy dogs were evaluated. The aetiology of AKI was multifactorial which included viper snake envenomation, pyometra, Babesiagibsoni infection, canine parvo viral infection, Ehrlichiacanis infection, leptospiral infection, bone meal poisoning and tetracycline-induced nephrotoxicity. Dogs with AKI were characterized into five gradesas per the guidelines provided by International Renal Interest Society. Parameters such asblood urea nitrogen (BUN), creatinine, urine output, urine protein-creatinine (UPC) ratio and blood pressure were estimated. Both BUN and creatinine was significantly higher in affected dogs. Majority of the dogs with AKI were oliguric and had the presence of proteinuria, occult blood and leucocytes on urine dipstick examination. Urine Protein-Creatinine ratio was increased whereas no significant variation was noticed in blood pressure of dogs with AKI.B-mode ultrasonography of kidneys revealedrenomegaly, hyperechoic cortex, decreased cortico-medullary differentiation and loss of architecture in majority of the dogs with AKI. Renal resistive index was significantly increased inAKI and a positive correlation was established between RRI and serumcreatinine but not with UPC ratio, blood pressure and size of kidneys. Re-evaluation of RRIseven days post treatment showed considerablereduction. It wasconcludedthat an increase in RRIwas associated with severity of renal parenchymal injuryin AKI and reduction of RRI post-treatment indicated favorable prognosis.

Evidence of Orthohantavirus and Leptospira Infections in Small Mammals in an Endemic Area of Sri Lanka

Evidence of Orthohantavirus and Leptospira Infections in Small Mammals in an Endemic Area of Sri Lanka

A Systematic Review of the geographic distribution of pathogenic Leptospira serovars in the Americas, 1930-2017

Leptospirosis is an important public health problem caused by Leptospira. The objective is to characterize the geographic distribution of pathogenic leptospira serovars in the Americas through a systematic review of the literature between 1930-2017. Searches were conducted in six scientific databases (PubMed, Web of Science, Embase, Lilacs, Scopus and Cochrane). We included studies conducted unambiguously in the Americas, that investigated infection of Leptospira in humans and animals in their natural environments with serovar identification. 283 articles were included, of which 69 were studies in humans, 86 in wild animals, and 182 in domestic animals. Most of them conducted in Brazil (104, 36.7%) and in rural environments (158, 55.8%). Bovines, equines and dogs where the most frequently studied domestic species. However, a large diversity including 80 species of wild animals were studied. Icterohaemorrhgiae, Canicola, Pomona and Grippotyphosa were the most common serovars, described in 46 (16.2%), 38 (13.3%), 32 (11.3%) and 26 (9%) of the articles, respectively. The Results indicate a large concentration of studies in Latin America, with emphasis on Brazil, in wild mammals and three main domestic animal groups. Our results emphasize the need for studies that delve into the relationships of the epidemiological cycle, environment, and health.

Development and Evaluation of Polyclonal Antibody-Based Antigen Detection Elisa and Dot Blot Assays as a Less Costly Diagnostic Alternative for Pathogenic Leptospira Infection

Development and Evaluation of Polyclonal Antibody-Based Antigen Detection Elisa and Dot Blot Assays as a Less Costly Diagnostic Alternative for Pathogenic Leptospira Infection

Sero-prevalence of anti-Leptospira antibodies and associated risk factors in rural Rwanda: A cross-sectional study.

BackgroundLeptospirosis is a zoonotic disease transmitted through the urine of wild and domestic animals, and is responsible for over 50,000 deaths each year. In East Africa, prevalence varies greatly, from as low as 7% in Kenya to 37% in Somalia. Transmission epidemiology also varies around the world, with research in Nicaragua showing that rodents are the most clinically important, while studies in Egypt and Chile suggest that dogs may play a more important role. There are no published studies of leptospirosis in Rwanda.Methods & findingsWe performed a cross-sectional survey of asymptomatic adults recruited from five occupational categories. Serum samples were tested using ELISA and Microscopic Agglutination Test (MAT). We found that 40.1% (151/377) of asymptomatic adults had been exposed to Leptospira spp. Almost 36.3% of positive subjects reported contact with rats (137/377) which represent 90.7% among positive leptospira serology compared with 48.2% of negative subjects (182/377) which represent 80.5% among negative leptospira serology (OR 2.37, CI 1.25–4.49) and 1.7 fold on prevalence ratio and 2.37 of odd ratio. Furthermore, being a crop farmer was significantly associated with leptospirosis (OR 2.06, CI 1.29–3.28). We identified 6 asymptomatic subjects (1.6%) who met criteria for acute infection.ConclusionsThis study demonstrates a high prevalence of leptospiral antibodies infection among asymptomatic adults in rural Rwanda, particularly relative to neighboring countries. Although positive subjects were more likely to report rat contact, we found no independent association between rats and leptospirosis infection. Nonetheless, exposure was high among crop farmers, which is supportive of the hypothesis that rats together with domestic livestock might contribute to the transmission.Further studies are needed to understand infecting Leptospira servers and elucidate the transmission epidemiology in Rwanda and identify means of host transmitters.

Crosstalk between E-Cadherin/β-Catenin and NF-κB Signaling Pathways: The Regulation of Host-Pathogen Interaction during Leptospirosis.

Approximately 1 million cases of leptospirosis, an emerging infectious zoonotic disease, are reported each year. Pathogenic Leptospira species express leucine-rich repeat (LRR) proteins that are rarely expressed in non-pathogenic Leptospira species. The LRR domain-containing protein family is vital for the virulence of pathogenic Leptospira species. In this study, the biological mechanisms of an essential LRR domain protein from pathogenic Leptospira were examined. The effects of Leptospira and recombinant LRR20 (rLRR20) on the expression levels of factors involved in signal transduction were examined using microarray, quantitative real-time polymerase chain reaction, and western blotting. The secreted biomarkers were measured using an enzyme-linked immunosorbent assay. rLRR20 colocalized with E-cadherin on the cell surface and activated the downstream transcription factor β-catenin, which subsequently promoted the expression of MMP7, a kidney injury biomarker. Additionally, MMP7 inhibitors were used to demonstrate that the secreted MMP7 degrades surface E-cadherin. This feedback inhibition mechanism downregulated surface E-cadherin expression and inhibited the colonization of Leptospira. The degradation of surface E-cadherin activated the NF-κB signal transduction pathway. Leptospirosis-associated acute kidney injury is associated with the secretion of NGAL, a downstream upregulated biomarker of the NF-κB signal transduction pathway. A working model was proposed to illustrate the crosstalk between E-cadherin/β-catenin and NF-κB signal transduction pathways during Leptospira infection. Thus, rLRR20 of Leptospira induces kidney injury in host cells and inhibits the adhesion and invasion of Leptospira through the upregulation of MMP7 and NGAL.

First Isolation and Molecular Typing of Pathogenic and Intermediate Leptospira Species from Urine of Symptomatic Dogs

Aim of this study was to evaluate, the presence and diversity of Leptospira spp. in blood and urine samples collected from 175 owned-dogs from Sardinia, Italy. After determination of leptospiral infection by microscopic agglutination test (MAT), urine from MAT-positive dogs were examined by real-time polymerase chain reaction (lipL32 rt-PCR) and then isolated by culture. In order to characterize obtained serovars, positive cultures were then subjected to 16S rRNA and secY sequencing, phylogenetic analysis and Multilocus Sequence Typing (MLST). Results showed that seven dogs (4%; 95% CI: 0–55) had Leptospira DNAs in their urine and five strains were isolated from urine cultures. The three different sequence types (ST17, ST198 and ST24) belonging to Leptospira interrogans genomospecies identified by MLST analyses in this study, confirmed that the leptospiral infection was widespread in Sardinian dogs. We also reported the first characterization of a new Leptospira spp. isolated from urine of one dog living in the study area. Whole genome sequencing and phylogenetic analysis, confirmed that this genospecies was closely related to Leptospira hovindhougenii, an intermediate Leptospira spp. with unknown pathogenicity previously isolated from a rat in Denmark. Further studies are required to clarify whether healthy dogs that shed leptospires in their urine could represent a zoonotic risk for humans in this region.

Immunoinformatics-Based Designing of a Multi-Epitope Chimeric Vaccine From Multi-Domain Outer Surface Antigens of Leptospira.

Accurate information on antigenic epitopes within a multi-domain antigen would provide insights into vaccine design and immunotherapy. The multi-domain outer surface Leptospira immunoglobulin-like (Lig) proteins LigA and LigB, consisting of 12–13 homologous bacterial Ig (Big)-like domains, are potential antigens of Leptospira interrogans. Currently, no effective vaccine is available against pathogenic Leptospira. Both the humoral immunity and cell-mediated immunity of the host play critical roles in defending against Leptospira infection. Here, we used immunoinformatics approaches to evaluate antigenic B-cell lymphocyte (BCL) and cytotoxic T-lymphocyte (CTL) epitopes from Lig proteins. Based on certain crucial parameters, potential epitopes that can stimulate both types of adaptive immune responses were selected to design a chimeric vaccine construct. Additionally, an adjuvant, the mycobacterial heparin-binding hemagglutinin adhesin (HBHA), was incorporated into the final multi-epitope vaccine construct with a suitable linker. The final construct was further scored for its antigenicity, allergenicity, and physicochemical parameters. A three-dimensional (3D) modeled construct of the vaccine was implied to interact with Toll-like receptor 4 (TLR4) using molecular docking. The stability of the vaccine construct with TLR4 was predicted with molecular dynamics simulation. Our results demonstrate the application of immunoinformatics and structure biology strategies to develop an epitope-specific chimeric vaccine from multi-domain proteins. The current findings will be useful for future experimental validation to ratify the immunogenicity of the chimera.

Risk and Predictive Factors of Leptospirosis in Dogs Diagnosed with Kidney and/or Liver Disease in Selangor, Malaysia.

Simple SummaryCanine leptospirosis is commonly associated with kidney and/or liver disease. The current study identified the potential risk and predictive factors of dogs diagnosed with kidney and/or liver disease due to leptospirosis. A total of 124 client-owned dogs were recruited and the samples collected were directly tested using polymerase chain reaction (PCR) and subsequently inoculated for bacterial isolation. Statistical analyses were descriptively analyzed, and risk analyses were performed using Pearson chi-square tests and logistic regression. The different breeds of dog with history of exposure to rats and those managed outdoors had a greater risk of leptospirosis (p < 0.05). The significant predictors for the dogs’ positivity were presence of rats and acute clinical illness (p < 0.05). Administration of antibiotics and detection of clinical illness at an early stage of the disease improved the survivability of the dogs (p < 0.05).Canine leptospirosis is commonly associated with kidney and/or liver disease. It has been widely reported and causes public health concerns due to its zoonotic potential and its re-emergence, resulting from close contact between humans and dogs. The current study identified potential risk and predictive factors for dogs diagnosed with kidney and/or liver disease due to leptospirosis. A total of 124 client-owned dogs were recruited, and information such as signalment, medical history, management, and clinical findings were documented. Samples collected from the recruited dogs were directly tested using polymerase chain reaction (PCR) and subsequently inoculated for bacterial isolation. Statistical analyses were descriptively analyzed, and risk analyses were performed using Pearson chi-square tests and logistic regression. A total of 53 dogs (42.7%) were positive for leptospiral infection based on PCR, and 10 leptospiral isolates were successfully recovered from eight dogs. The mortality rate of infected dogs was 34.0% (18/53). Medium and large dog breeds, with a history of exposure to rats, and managed outdoors had a greater risk for leptospirosis (p < 0.05). The significant predictors for the dogs’ positivity were the presence of rats and acute clinical illness (p < 0.05). Administration of antibiotics and the detection of clinical illness at an early stage of the disease improved the survivability of the dogs (p < 0.05). Identifying the profile of dogs that are at risk to leptospirosis could be useful in the design of diagnostic and treatment strategies, as well as to increase awareness for prevention of the disease.

Galleria mellonella infection model to evaluate pathogenic and nonpathogenic Leptospira strains

The Galleria mellonella larvae infection model is emerging as a valuable tool for studying various characteristics of infectious agents and host-pathogen interaction. This system has been widely recognized as a high throughput, ethical, and cost-effective invertebrate infection model to study the virulence and pathogenesis of various bacterial pathogens. In this study, we compared the effect of Leptospira infection in G. mellonella larvae infected with Leptospira interrogans serovar Copenhageni (pathogenic) or Leptospira biflexa serovar Patoc (saprophytic) strains. We observed significant pathologic changes such as decreased activity, complete melanization, and lower survival rate in the G. mellonella larvae infected with a pathogenic strain L. interrogans serovar Copenhageni compared to those infected with a nonpathogenic strain L. biflexa serovar Patoc. Our study demonstrates the feasibility and the potential of using G. mellonella larvae as an alternative model to study virulence mechanisms and pathogenesis of Leptospira strains. Once optimized, the G. mellonella infection model can be a potential substitute for hamsters to explore various host and pathogen-related mechanistic events in Leptospira infection.

C87. Serial Cases of Cardiovascular Manifestation on Leptospirosis: A Tales of Unfortunate Events

Abstract Background Leptospirosis is a zoonosis disease caused by Leptospira species. It's endemic and has become a major public health issue, especially in tropical regions. Clinical manifestation varies from mild or asymptomatic to severe multiple organ failure. We report cases of severe leptospirosis which complicates supraventricular tachycardia and myoperdicarditis from Universitas Sebelas Maret Academic Hospital. Case Summary The first case was a 44-year-old man referred from Internal Medicine Department with Leptospira infection with Weil’s disease. On 5th daycare, the patient was reporting had an episode of tachyarrhythmia, the ECG show SVT-AVNRT, there was no history of arrhythmic events before admitted to the hospital, the echocardiography was normal. The second case was a 67-year-old man who was referred from emergency department with shortness of breath, the ECG reveals diffuse ST-segment elevation in all limb and precordial leads with reciprocal ST-depression at aVR and V1, there was also downsloping of the PR and TP segment on precordial leads (Spodick’s sign), with normal ejection fraction on echocardiographic examination with pericardial thickening. Both patients have hsTroponin levels rose above the normal limit and serological testing found positive leptospira IgM. Discussion Severe leptospirosis can cause multi-organ dysfunction including cardiac involvement. The patients, in this case, suffered from leptospirosis with SVT-AVNRT and myopericarditis. The exact pathophysiology is still unclear, but there are several hypotheses, such as cytokine storms and direct damage from leptospira endotoxins. Arrhythmias and cardiac disturbance in leptospirosis patients are associated with poor outcomes and higher mortality rates.

C87. Serial Cases of Cardiovascular Manifestation on Leptospirosis: A Tales of Unfortunate Events

Abstract Background Leptospirosis is a zoonosis disease caused by Leptospira species. It's endemic and has become a major public health issue, especially in tropical regions. Clinical manifestation varies from mild or asymptomatic to severe multiple organ failure. We report cases of severe leptospirosis which complicates supraventricular tachycardia and myoperdicarditis from Universitas Sebelas Maret Academic Hospital. Case Summary The first case was a 44-year-old man referred from Internal Medicine Department with Leptospira infection with Weil’s disease. On 5th daycare, the patient was reporting had an episode of tachyarrhythmia, the ECG show SVT-AVNRT, there was no history of arrhythmic events before admitted to the hospital, the echocardiography was normal. The second case was a 67-year-old man who was referred from emergency department with shortness of breath, the ECG reveals diffuse ST-segment elevation in all limb and precordial leads with reciprocal ST-depression at aVR and V1, there was also downsloping of the PR and TP segment on precordial leads (Spodick’s sign), with normal ejection fraction on echocardiographic examination with pericardial thickening. Both patients have hsTroponin levels rose above the normal limit and serological testing found positive leptospira IgM. Discussion Severe leptospirosis can cause multi-organ dysfunction including cardiac involvement. The patients, in this case, suffered from leptospirosis with SVT-AVNRT and myopericarditis. The exact pathophysiology is still unclear, but there are several hypotheses, such as cytokine storms and direct damage from leptospira endotoxins. Arrhythmias and cardiac disturbance in leptospirosis patients are associated with poor outcomes and higher mortality rates.

Serologic titers to Leptospira in vaccinated pigs and interpretation for surveillance.

Diagnosis and surveillance of pathogenic Leptospira is difficult as organisms may be intermittently shed and in small numbers. Therefore, serologic testing by the microscopic agglutination test (MAT) is the primary screening method for leptospirosis. While a MAT titer ≥1:100 is considered to be a positive result, interpretation is complicated by the use of commercial vaccines in pigs. Most guidelines for interpretation of MAT titers in pigs were published in the 1970’s and 1980’s, prior to the development of the current multivalent vaccines. We evaluated MAT titers in routinely vaccinated healthy research pigs compared to their unvaccinated cohorts. Our study confirmed previous reports that the Pomona serovar elicits minimal antibody response even after a second booster 6 months after initial vaccination. However, MAT titers of ≥1:3,200 were detected as early as 4 weeks post initial vaccination for serovars Bratislava and Icterohaemorrhagiae and remained as high as ≥1:1,600 prior to booster at 24 weeks post vaccination. Our study determined that high levels of MAT titers can occur from vaccination alone and high titers are not necessarily indicative of infection. Therefore, the interpretation of MAT titers as indicators of Leptospira infection should be readdressed.

The viability of Leptospira is related to physicochemical properties of the surface water surrounding an agricultural area and HemO and LipL32 gene expression in response to iron in water

The pathogenic Leptospira can survive and contaminate surface water based on physicochemical factors. This study aimed to determine how the physicochemical properties of water sources influence the growth and effect of iron on the gene expression of Leptospira spp. P47. Surface water samples (n=55) were collected and used for Leptospira spp. P47 cultivation. Physicochemical factors, including iron, calcium, magnesium and pH, were analyzed. The association between Leptospira spp. P47 viability at days 5, 10 and 15 with the physicochemical factors were analyzed. In addition, this bacterium was cultured in six selected water samples. The effect of iron in water on HemO and LipL32 gene expression was determined by relative quantification real-time PCR. Leptospira viability at day 5 was not significantly correlated with physicochemical factors, while Leptospira viability at day 10 was associated with both pH and iron. The Leptospira viability rate at day 15 had a significantly positive association with pH and iron and a negative association with calcium. HemO expression was significantly increased, mostly in selected water samples and under iron-depleted conditions. Conversely, LipL32 expression was significantly decreased in all water samples. Physicochemical factors in natural surface waters are key factors for bacterial survival in the environment, which may increase the chance of Leptospira infection in humans.

Emergency vaccine immunization protects hamsters against acute leptospirosis

Leptospirosis, caused by pathogenic Leptospira, is a global critical zoonotic disease in terms of mortality and morbidity. Vaccines are often used to prevent leptospirosis. However, few studies have reported the therapeutic effect of a vaccine against Leptospira infection. This study demonstrates the efficacy of the emergency vaccine immunization against acute leptospirosis in hamsters. Treatment with a whole-cell vaccine (Leptospira interrogans serovar Lai) at 24 h post-infection improved the survival rate of hamsters with lower leptospiral burden and minor pathological damage to organs. The vaccine also protected against multiple Leptospira serotypes acute infection. However, the protective effect of the vaccines was lost when beginning treatment at 36 h or 48 h post-infection. These results indicated that vaccines could treat acute leptospirosis in hamsters, but only if immunization is within 24 h after infection.

Review on the Prevalence and Laboratory Diagnosis of Leptospira Infection in Nigeria

Review on the Prevalence and Laboratory Diagnosis of Leptospira Infection in Nigeria