Seroreactivity against Leptospira spp. differs between community cats and privately-owned cats in Hong Kong.

Leptospirosis is a bacterial zoonotic disease of major One Health significance and public health impact globally, with a wide host range including mammals, cetaceans and herpetofauna. This study aimed to determine Leptospira seroprevalence, risk factors for seroreactivity and prevalence of urinary Leptospira shedding among domestic cats in Hong Kong. Microagglutination testing of 22 Leptospira serovars from 20 serogroups was performed on 738 sera from outdoor free-roaming "community" cats (n = 391) and privately-owned (n = 347) cats. Urine from 268 community cats was tested for pathogenic Leptospira DNA by qPCR targeting lipL32. Potential risk factors associated with exposure were assessed using logistic regression. Overall Leptospira seroprevalence was 9.35%. Of 14 serogroups detected, Javanica (4.3%), Djasiman (2.3%) and Australis (1.5%) were most common. Seroreactivity was significantly higher among community (13.3%) than privately-owned cats (4.9%; OR 2.98 [95% CI 1.68-5.25], P < 0.001), especially to Javanica (7.65% of community cats versus 0.58% of privately-owned cats (P < 0.001). Antibody titres to all serogroups ranged from 1:100 to 1:6400 (median 1:200) and were highest for Javanica (median 1:800). Leptospira DNA was detected in urine from 12/268 community cats (4.48%; median load 6.42 × 102 copies/mL urine; range 1.40 × 101-9.63 × 104). One in three seroreactive community cats with paired urine and blood samples had leptospiruria. After adjusting for source, none of breed, sex, neuter status, age, district rodent infestation rate, serum alanine transaminase or creatinine values were associated with seroreactivity. Cats in Hong Kong are exposed to a diversity of Leptospira serogroups and can shed Leptospira silently in urine. The higher seroprevalence among outdoor free-roaming community cats highlights the importance of environmental drivers in leptospirosis transmission and risks of exposure for sympatric human populations. Gloves should be worn when handling feline urine to minimise the risk of zoonotic transmission from subclinically infected cats.

Infection and re-infection of Leptospira spp. in stray dogs and cats from Bogota, Colombia.

Background and Aim: Leptospirosis is a re-emerging zoonosis that is under-reported in tropical countries, and canines can be a potential reservoir of the disease. The objective of this study was to diagnose Leptospira spp. that is actively infected and re-infected in stray dogs and cats from Bogota, D.C., Colombia. Materials and Methods: A sample of 200 animals, including dogs and cats from the animal protection programs of Bogota, Colombia, were used in this study. Blood was collected from these animals for serum and DNA analysis. Conventional polymerase chain reaction (PCR) was performed using the 16s rRNA primer set, and higher-quality amplification products were sequenced by Sanger. For serodiagnosis, a group of PCR-positive samples was tested using the microagglutination test (MAT). Results: The overall PCR positivity of stray dogs and cats was 56%, 52.9%, and 65.3% in dogs and cats, respectively. The MAT seropositivity was 77.3%, and only dogs showed titers higher than 1:400. Canicola, Icterohaemorrhagiae, Pomona, Hardjo Prajitno, and Canicola and Hardjo prajitno were the serogroups associated with dogs and cats, respectively. Phylogenetic analysis revealed that the strains belonging to Leptospira interrogans serovars related to isolated samples of American, European, and Asian bats (Myotis myotis), dogs, and bovines of American origin. Conclusion: These results showed that stray dogs and cats were previously exposed to different serovars of Leptospira spp. and re-infected with other serovars that actively participated in the transmission cycle. These findings highlight the importance of actively diagnosing infectious animals to design effective intervention strategies.

Why do Doctors Miss the Diagnosis of Leptospiral Uveitis? Emergence of New Serovars and Challenges in Diagnosis.

PURPOSE: Leptospirosis is an endemic disease in India and uveitis is its late complication. Several Indian reports showed diversity of serovars, changing patterns and existence of new serovars. Failure to add new serovars in testing panel result in increased false-negativity in serology. AIM: To analyse seroprevalence, changing patterns and to discuss the resulting challenges in diagnosis. METHODS: In this retrospective study covering the period from 1994 to 2020, we analysed data from laboratory records of patients diagnosed with leptospiral uveitis in South India. Microscopic agglutination Test (MAT) and/or Enzyme-Linked Immunosorbent Assay (ELISA) were performed on clinically diagnosed leptospiral uveitis cases from our hospital, as well as on systemic leptospirosis patients from government and private hospitals. RESULTS: Out of a total of 87 216 new uveitis cases with varying causes over 27 years, 3,658 (4.1%) were clinically diagnosed as leptospiral uveitis. Among them, 1,268 (34.7%) patients were seropositive. In 1994, 92% of clinically diagnosed leptospirosis patients were seropositive in the MAT performed at the Centers for Disease Control and Prevention in Atlanta. However, the positivity rate gradually declined to 35% over the years. The predominant serovars identified were L. autumnalis, L. icterohaemorrhagiae, and L. australis. There were notable variations in the distribution of serovars over the years. CONCLUSIONS: The data suggest a declining sensitivity of MAT and ELISA, possibly due to the emergence of new serovars. Customizing the panel based on local isolates could enhance the performance of MAT. Critical need is the addition of advanced molecular techniques to improve the diagnosis.

Leptospiral uveitis- "Transition 'from epidemic to endemic form" difficulties in laboratory confirmations.

Purpose: Leptospirosis is a waterborne zoonotic disease that primarily causes systemic illness, followed by uveitis. After heavy flooding in Madurai district, an epidemic outbreak of systemic and ocular leptospirosis occurred in 1994. Our data shows a transition to endemicity after each epidemic. Aim: The aim of this study is to report the clinical signs, epidemic outbreaks, and persistent endemicity of leptospiral uveitis, as well as the diagnostic dilemmas associated with it. Methods: A retrospective analysis of clinical signs was conducted using medical records of leptospiral uveitis patients over a period of 27 years (1994-2020) in a tertiary care eye hospital. The clinical workup of uveitis included a detailed clinical history, systemic, and ophthalmic examination. Microagglutination tests (MATs) was done at the Centers for Disease Control and Prevention (CDC) in Atlanta and later in our regional laboratory. Serum samples were collected from human systemic leptospirosis cases and a small group of animals in and around Madurai. Results: The first epidemic outbreak resulted in 200 seropositive patients. Subsequent epidemic outbreaks occurred in 1997, 1998, 2001, 2005, and 2012, with Madurai experiencing multiple outbreaks. However, the disease remained endemic, with 25-50 patients being observed per year in between the peaks. Ocular examination revealed acute non-granulomatous uveitis (94.9%), pan uveitis (59.8%), vitreous inflammatory reaction (55.4%), retinal vasculitis (29.5%), disc hyperemia (20.9%), and hypopyon. (16.2%). New serovars emerged every year, resulting in decreased sensitivity of the MAT. Over time, the MAT started to miss diagnoses. Conclusion: The persistent endemicity of leptospiral uveitis emphasizes the need for accessible diagnostic tests. The low performance of the MAT can be attributable to the use of an older panel. The incorporation of new isolates in the MAT by a national laboratory will improve the accuracy of diagnosis.

Leptospira seroprevalence and associated risk factors in healthy Swedish dogs.

BACKGROUND: Leptospirosis is an emerging zoonotic infection worldwide and a cause of life-threatening disease in dogs. Seroprevalence in Swedish dogs is unknown. The aims of the present study were to estimate seroprevalence of pathogenic Leptospira in healthy dogs in Sweden using the microagglutination test (MAT) and a rapid point-of-care enzyme-linked immunosorbent assay (ELISA), and to evaluate risk factors of Leptospira exposure in Swedish dogs. RESULTS: Positive MAT titres (≥ 1:50) were detected in 27/369 (7.3%) of included dogs. Five different serovars were represented of which the Saxkoebing serovar was the most common (64.3%), followed by Copenhagi (14.3%), Bratislava (10.7%), Icterohaemorrhagiae (7.1%), and Canicola (3.6%). The ELISA test (SNAP® Lepto) was positive in 3/316 (0.9%) dogs. Living in urban areas and contact with stagnant water were found to be risk factors for Leptospira seropositivity (p < 0.05) in a multivariable logistic regression model. CONCLUSION: In this first seroprevalence study of Leptospira in Swedish dogs, it was shown that healthy dogs without recent (24 months) travel history and antileptospira vaccination had been exposed to pathogenic Leptospira interrogans serovars. Contact with stagnant water and living in urban areas were independent risk factors for seropositivity.

Seroprevalence and Molecular Characterization of Leptospira spp. in Rats Captured near Pig Farms in Colombia.

Gram-negative spirochete Leptospira spp. causes leptospirosis. Leptospirosis is still a neglected disease, even though it can cause potentially fatal infections in a variety of species including humans. The purpose of this study was to determine the seroprevalence of leptospirosis in pig farm captured rodents and characterize the isolated samples. Rats were captured, sampled, and euthanized in the vicinity of pig farms to obtain serum for microagglutination tests (MAT) and kidney tissues for PCR amplification of the 16S rRNA and LipL32 genes. A fraction of the 16S rRNA PCR product was sequenced and phylogenetically analyzed. The results showed a Leptospira seroprevalence of 13.8% (77/555) among the 555 captured rats. PCR positivity for Leptospira spp. reached 31.2% (156/500), and the positivity for pathogenic Leptospira spp. was 4% (22/500). Phylogenetic analysis matched eight samples with L. interrogans serovar icterohaemorrhagiae and two with L. interrogans serovar pyrogenes. Two sequences were located within the pathogenic Leptospira clade but did not match with any specific strain. The seroprevalence found in the rats around swine farms indicates a potential risk of transmission to the pigs. The identification of pathogenic Leptospira outlines the importance of more research as well as updating the current strategies for the diagnosis, control, and prevention of porcine leptospirosis in Colombia.

Circulating serogroups of Leptospira in swine from a 7-year study in France (2011-2017).

BACKGROUND: Leptospirosis is a widespread zoonotic disease caused by pathogenic Leptospira and is responsible for significant economic porcine livestock losses. Knowledge of Leptospira serogroups and their distributions is important for evaluation of the relevance of leptospirosis management measures, including use of the prophylactic vaccine that was recently made available in France. A retrospective study was conducted to determine the relationships between different circulating Leptospira serogroups. Pigs from across France presenting clinical signs suggestive of leptospirosis were tested with the microagglutination test (MAT) between 2011 and 2017. We used weighted averages to determine serogroup distributions according to MAT results and considering cross-reactions. RESULTS: A total of 19,395 pig sera, mostly from Brittany, were tested, and 22.7% were found to be positive for at least one Leptospira serogroup. Analysis of the 4,346 seropositive results for which the putative infective serogroup could be defined, revealed that two out of ten serogroups were much more frequent than the others: Australis (48.5%) and Icterohaemorrhagiae (38.2%). Other serogroups, including Autumnalis, Panama, Ballum, Tarassovi, Sejroe, Grippotyphosa, Bataviae, and Pomona, were less common. CONCLUSIONS: Although diagnostic laboratory data cannot be extrapolated to infer the distribution of Leptospira serogroups at the nationwide scale in France, the analysis of such data can provide an overview of the relationship between circulating Leptospira serogroups in space and time. During the last decade, protection against the serogroups Australis and Icterohaemorrhagiae would have prevented most of the clinical porcine leptospirosis cases in the large number of farms that we studied. In the future, epidemiological information related to circulating Leptospira serogroups should be extracted from data with a standardized approach for use in nationwide or international surveillance and prophylactic strategy support.

Are Small Animal Practitioners Occupationally Exposed to Leptospirosis? Results of a Serological Survey.

Leptospirosis is a worldwide zoonosis frequently responsible for clinical disease in dogs and rarely reported in human people. The risk of human exposure to Leptospira has been investigated in a sample population working in the northeast of Italy, a geographical area with high endemicity of canine leptospirosis. Two-hundred twenty-one human serum samples were analyzed for Leptospira microagglutination test (MAT): 112 clinical freelance small animal practitioners (exposed subjects) and 109 people not occupationally exposed to Leptospira-infected animals (unexposed subjects) were voluntarily enrolled. Despite the previously reported serological detection of antibodies vs. Leptospira in people in different Italian regions, this study did not detect any reactivity in the investigated population. This study shows that veterinarians do not appear to be at a greater risk of leptospirosis than the reference population. This may be due to both veterinarian awareness of the Leptospira zoonotic risk and the efficiency of the preventive measures and management of patients. Moreover, it could be the result of the relatively low excretion of Leptospira in symptomatic dogs, which can be considered as an environmental sentinel for Leptospira presence rather than a vehicle of transmission.

SEROLOGIC SURVEY OF LEPTOSPIRA SPP. IN CAPTIVE ANIMALS FROM VERACRUZ, MEXICO.

Leptospirosis is the most common zoonotic disease worldwide and is considered endemic in countries with tropical climates. It is caused by 10 species of the Leptospira genus and by more than 275 serovars which can affect a wide range of vertebrates. In the Americas, 122 species of four classes of vertebrates have been reported to be infected or exposed to many Leptospira species. Many of these reports are from zoos and rehabilitation centers. Mexico has one single study that reported antibody titers against Leptospira in zoo animals. The purpose of this research was to identify the degree of exposure of some captive mammals and reptiles in Veracruz, a Mexican state with endemic leptospirosis, through microagglutination using 14 live strains of five Leptospira species. Sera samples were collected from 55 animals of 11 species from two classes (Mammalia and Reptilia), four orders (Primates, Artiodactyla, Carnivora, Crocodilia), and nine genera. The more prevalent serovars were Icterohaemorrhagiae and Tarassovi and the highest titers were reactive to the serovar Icterohaemorrhagiae with a value of 1: 51,200.

Application of PCR for Specific Diagnosis of Leptospirosis in Humans in Ukraine.

Leptospirosis remains one of the most widespread zoonotic diseases in the world and Ukraine, in particular. Ukrainian clinicians have been faced with early detection of the disease due to the availability of only a serological method for routine diagnostics in Ukraine, namely the microscopic agglutination test (MAT). This paper demonstrates the first results of the complex application of MAT and polymerase chain reaction (PCR) for routine verification of leptospirosis, which were first applied simultaneously in Lviv Oblast of Ukraine in 2016. We examined the sera of 150 patients clinically suspected of leptospirosis, 31 of whom were treated at the Lviv Oblast Clinical Hospital for Infectious Diseases (LOCHID). The application of PCR during the first seven days of the disease allowed increasing the share of confirmed leptospirosis cases by 16,1% in patients that were treated in LOCHID during 2016-2017.

Seroprevalence and risk factors associated with equineleptospirosis in the metropolitan region of Salvador and Recôncavo Baiano region, Bahia state (NE Brazil).

Equine leptospirosis, although usually asymptomatic, has been associated with recurrent uveitis, abortion, and other systemic signs, constituting a major economic loss in the equine agribusiness sector. The occurrence of anti-Leptospira spp. agglutinins were investigated in 1200 serum samples of horses from 27 municipalities of the Recôncavo Baiano region, Bahia state (NE Brazil), besides the risk factors related to animals and their cattle farms. The microscopic agglutination test (MAT) was performed using 13 serogroups of Leptospira spp. as antigens. From 1200 analyzed equines, 97 (8%) were considered as positive, which obtained titer equal to or higher than 200. In 22 (78.6%) from the 28 properties, at least one animal was detected as seropositive. The most prevalent serogroup in animals, raised in stables, was the Australis (serovar Bratislava) 67%; in mounted police animals was the Sejroe (serovar Wolffi and Hardjobovis) 50%; and equestrian animals was the Australis (serovar Bratislava) 25% and Icterohaemorrhagiae (serovar Copenhageni) 25%. Equine leptospirosis is present in most cattle farms of the region studied. The risk factors of major importance regarded the semi-extensive livestock farming, the land topography of the cattle farm, the contact with animals in neighboring properties, and cohabitation with goats.

Diagnosis of canine leptospirosis: evaluation of two PCR assays in comparison with the microagglutination test / Diagnóstico de leptospirose canina: avaliação de dois ensaios de PCR em comparação com o teste de microaglutinação

Canine leptospirosis is definitely diagnosed by demonstrating seroconversion in paired serum samples from the acute and convalescent period by the microagglutination test (MAT). However, the application of a polymerase chain reaction (PCR) assay can provide earlier confirmation of suspected cases. The objective of this study was to evaluate two PCR assays used in diagnosis of human leptospirosis (lipL32 real-time PCR and rrs conventional PCR) in cultured microorganisms and experimentally contaminated samples (whole blood, serum, urine), and investigate their applicability in clinical samples from dogs with presumptive diagnosis of leptospirosis by using the MAT as a reference. The analytical sensitivity of the lipL32 real-time PCR was 1 genome equivalent per reaction, whereas that for the rrs conventional PCR was 10 genome equivalents per reaction. Both assays amplified the pathogenic strains but were negative when evaluating the DNA of other microorganisms that may be present in clinical samples. The lipL32 real-time PCR detected 100 bacteria/mL in whole blood samples, 1000 bacteria/mL in serum samples and 10 bacteria/mL in urine samples, whereas the rrs conventional PCR detected 1000 bacteria/mL in whole blood and serum samples and 100 bacteria/mL in urine samples. Seven out of the 51 samples from dogs with presumptive diagnosis of leptospirosis were considered as confirmed cases. ThelipL32 real-time PCR detected positive results in six of the seven confirmed cases, whereas the rrs conventional PCR detected four. The PCR assays evaluated proved to be useful diagnostic tools in the confirmation of canine leptospirosis when used together with the MAT.(AU)

O diagnóstico definitivo da leptospirose canina é geralmente realizado demonstrando a seroconversão em amostras do paciente no período agudo e de convalescença por serologia. No entanto, a aplicação de técnicas de PCR pode contribuir para a confirmação de casos suspeitos num período de tempo mais curto. O objetivo deste estudo foi avaliar dois ensaios de PCR publicados em humanos (PCR-lipL32 em tempo real e PCR-rrs convencional) em culturas puras e em amostras de sangue com anticoagulante, soro e urina experimentalmente contaminados. Posteriormente, investigamos a utilidade de ambos os ensaios de PCR em amostras clínicas de cães com suspeita de leptospirose tomando a técnica de microaglutinação (MAT) como referência. A sensibilidade analítica foi de 1 e 10 genoma equivalente por reação para PCR-lipL32 em tempo real e para PCR-rrs convencional, respectivamente. Ambos os ensaios amplificaram corretamente as 14 estirpes patogênicas, mas foram negativos para avaliar o ADN de outros microrganismos que poderiam estar presentes em amostras clinicas. Em nas amostras experimentalmente contaminadas PCR-LipL32 em tempo real detectou 100 bactérias/mL em sangue total, 1000 bactérias/mL em soro e 10 bactérias/mL em urina. Enquanto o PCR-rrs convencional detectou 1000 bactérias/mL em sangue total e soro e 100 bactérias/mL na urina. Dos 51 cães suspeitos, sete foram considerados casos confirmados pela MAT. O PCR-lipL 32 em tempo real detectou seis dos sete casos confirmados, enquanto o PCR-rrs convencional foi positivo em quatro deles. As técnicas de PCR avaliadas provaram ser uma ferramenta de diagnóstico útil na confirmação de casos clínicos caninos quando utilizados em conjunto com a técnica MAT.(AU)

Leptospirosis in Ukraine (Lviv Oblast): Clinical and Epidemiological Features.

The article describes the results of a retrospective analysis of medical records of 395 patients with a clinical diagnosis of leptospirosis treated at the Lviv Oblast Infectious Disease Clinical Hospital (Ukraine) between 2002 and 2016. The main risk factors for leptospirosis were contact with rodents or their excrements (26.84%) and bathing in ponds, small lakes, and reservoirs (10.63%). Among 276 patients in whom the anti-leptospira antibodies were detected by the microscopic agglutination test (MAT), the most common serotypes were Leptospira icterohaemorrhagiae (33.33%) and Leptospira grippotyphosa (25.0%). The mortality rate was significantly higher in patients where leptospirosis diagnosis was established based on clinical symptoms without confirmation by MAT (15.13% vs. 5.43%, p < 0.01).

[Diagnostic procedure after abortions in sows after simultaneous infection with leptospira and chlamydia]. / Diagnostische Abklärung von Aborten bei Zuchtsauen nach Leptospiren- und Chlamydieninfektion.

INTRODUCTION: In a farrowing farm 2 first parity sows aborted on day 95 and day 110 of gestation due to an infection with leptospira and chlamydia. The double infection was diagnosed by PCR examination of abortion material. Serum samples of both sows and additional 8 sows taken three weeks after abortions were sent to two different labs for serological examination for antibodies against leptospira and chlamydia using a microagglutination test and a complement fixation test, respectively. In both labs the tests for antibodies against chlamydia were negative. Titers against diverse leptospira serovars varied between both labs and were low, so that they were not indicative for the involvement of the two pathogens regarding abortion. This case report indicates the diagnostic difficulties of direct and indirect detection methods for leptospira and chlamydia to assess the impact of these pathogens on observed reproductive failure.

Seroprevalencia de leptospirosis en pacientes con síndrome febril no palúdico / Seroprevalence of leptospirosis in patients with non-malarial febrile syndrome

Introducción: la leptospirosis es una enfermedad zoonótica transmitida por varias especies de animales domésticos y silvestres que actúan como reservorios del agente causal y que afecta humanos que habitan áreas urbanas y rurales en el mundo. Objetivo: determinar la seroprevalencia de anticuerpos contra Leptospira sp. y los serogrupos dominantes, en pacientes con síndrome febril no palúdico del departamento del Meta, Colombia. Métodos: se realizó un estudio prospectivo de corte trasversal. La población la conformó todo paciente febril que asistiera a un hospital en la ciudad de Villavicencio, entre mayo de 2013 y junio de 2014. Los sueros pareados fueron procesados utilizando la prueba de microaglutinación con los serogrupos: Australis, Ballum, Bataviae, Canicola, Cynopteri, Panama, Pyrogenes, Sejroe, Semaranga. Se practicaron pruebas para diagnóstico de dengue (detección de anticuerpos IgM e IgG por ELISA), rickettsiosis (detección de anticuerpos IgG por inmunofluoresencia indirecta), hantavirosis (detección de anticuerpos IgG por ELISA). Resultados: de los 100 sueros estudiados, 29 resultaron positivos para leptospirosis. Los serogrupos más prevalentes fueron Canicola y Ballum. Conclusiones: los resultados de la prevalencia de leptospirosis muestran que esta enfermedad es subregistrada en la zona, por lo que sería recomendable que estuviera dentro del diagnóstico diferencial de los síndromes febriles(AU)

Introduction: leptospirosis is a zoonotic disease transmitted by several species of wild and domestic animals, which serve as reservoirs of the causative agent. The disease affects humans from urban and rural areas of the world. Objective: determine Leptospira sp. antibody seroprevalence and dominant serogroups in patients with non-malarial febrile syndrome from Meta Department in Colombia. Methods: across-sectional prospective study was conducted. The study population was all the febrile patients attending a hospital in the city of Villavicencio from May 2013 to June 2014. The paired sera were processed using the microagglutination test with the following serogroups: Australis, Ballum, Bataviae, Canicola, Cynopteri, Panama, Pyrogenes, Sejroe and Semaranga. Diagnostic tests were performed for dengue (IgM and IgG antibody detection by ELISA), rickettsiosis (IgG antibody detection by indirect immunofluorescence), and hantaviral disease (IgG antibody detection by ELISA). Results: of the 100 sera studied, 29 were positive for leptospirosis. The most prevalent serogroups were Canicola and Ballum. Conclusions: prevalence results for leptospirosis show that the disease has been under-recorded in the area. It is thus advisable to include it in the differential diagnosis of febrile syndromes(AU)

Cepario autóctono de leptospiras en la prueba de micro - aglutinación / Micro - agglutination test of Autogenous leptospirosis

Introducción: leptospirosis. Zoonosis más frecuente en Cuba, como enfermedad infecto-contagiosa. Objetivos: identificar las cepas de leptospiras aisladas localmente, para ser empleadas en la prueba de microaglutinación. Apreciar su comportamiento serológico frente a las cepas de referencia. Método: estudio experimental, de sueros de pacientes presuntivos de padecer Leptospirosis, con 60 muestras, en el Instituto Carlos J. Finlay, de La Habana. Identificación de 40 sueros reactores a la hemaglutinación pasiva. Identificación de 34 cepas, de un total de 250 aislamientos, a partir de hemocultivos, de pacientes con antisueros policlonales a serogrupos y anticuerpos monoclonales a serovar. Se conformaron cinco cepasrepresentativas de los serovares: Ballum Ballum, Canicola Canicola, Pomona Pomona, Hebdomadis Wolffi e Icterohaemorrhagiae Copenhageni, como las de mayor circulación en la región. Se realizó la prueba de microaglutinación con las cepas aisladas localmente, y las de referencia de forma paralela. Resultados: mayor reactividad con las cepas locales, y conformación de cinco cepas representantes de los serovares: Ballum Ballum, Canicola Canicola, Pomona Pomona, Hebdomadis Wolffi e Icterohaemorrhagiae Copenhageni, como las de mayor circulación en la región. Se encontró una concordancia de 86,36% en la reactividad. Conclusiones: los resultados mostraron mayor reactividad con las cepas locales que con las de referencia, elevada concordancia e incremento de los títulos de anticuerpos de los sueros reactores usando cepas locales, y disminución del promedio de las reacciones cruzadas cuando se utilizaron las cepas locales. Se demostró su utilidad en la evaluación de estudios inmunológicos.

Introduction: leptospirosis, a contagious infectious disease considered the most common zoonosis in Cuba. Objectives: to identify locally isolated leptospirosis strains for micro- agglutination test. To evaluate their serological behavior against the reference strains. Method: an experimental study of 60 presumptive Leptospirosis patients' serum samples. Forty sera reactive to passive hemagglutination. To isolate 250 blood cultures of patients. To show 34 strains identified at the Carlos J. Finlay Institute, with polyclonal antisera to serogroups and monoclonal antibodies to serovar. Five strains represented by the serovars: Ballum Ballum, Canicola Canicola, Pomona Pomona, Hebdomadis Wolffi and Icterohaemorrhagiae Copenhageni, were the most circulating strains in the region. The microagglutination test was performed in parallel form to locally isolated strains and reference strains Results: greater reactivity with the local strains. Five strains representing the serovars: Ballum Ballum, Canicola Canicola, Pomona Pomona, Hebdomadis Wolffi and Icterohaemorrhagiae copenhageni as the most circulating in the region. The reactivity showed 86.36% concordance. Conclusions: there was greater reactivity with the local strains than the reference strains. A higher concordance increased the titers of antibodies of the reactive sera, by the use of local strains. The average of cross reactions decreased when the local strains were used. The evaluation of immunological studies was demonstrated.

Determination of O:4 antigen-antibody affinity level in O:5 antigen positive and negative variants of Salmonella enterica serovar Typhimurium.

Salmonella enterica serovar Typhimurium (S. Typhimurium) has two serological variants: one that expresses the O:5 antigen (1,4,5,12:i:1,2) and one that lacks O:5 antigen (1,4,12:i:1,2). For serotyping, S. Typhimurium is agglutinated by diagnostic O:4 antigen serum. This study was carried out to compare the antigen-antibody affinity of O:4 antigen in S. Typhimurium χ3306 O:5-positive and S. Typhimurium χ3306 O:5-negative strains. The affinity of O:4 antigen with O:4 antigen serum was found to be stronger in the O:5-negative strains compared to O:5-positive strains. Next, we investigated the antigen-antibody affinity of O:4 antigen with O:4 antigen serum in field strains of S. Typhimurium, which showed the same tendency in affinity as seen with S. Typhimurium χ3306 O:5-positive and negative strains. This study suggests that the presence or absence of O:5 antigen causes differences in O:4 agglutination reactions with different field strains of S. Typhimurium.

ECO-EPIZOOTIOLOGIC STUDY OF FRANCISELLA TULARENSIS, THE AGENT OF TULAREMIA, IN QUÉBEC WILDLIFE.

In Canada, Francisella tularensis , the zoonotic bacterial agent of tularemia, affects mostly snowshoe hares ( Lepus americanus ), muskrats ( Ondatra zibethicus ), and beavers ( Castor canadensis ). Despite numerous studies, the ecologic cycle and natural reservoirs of F. tularensis are not clearly defined. We conducted a cross-sectional study to estimate the prevalence of F. tularensis in snowshoe hares, muskrats, and coyotes ( Canis latrans ) in four regions of Québec, Canada, and to describe the risk of infection in relation to host and environmental characteristics at three spatial scales. Between October 2012 and April 2013, trappers captured 345 snowshoe hares, 411 muskrats, and 385 coyotes. Blood samples were tested by microagglutination tests, and DNA extracts of liver, kidney, lung, and spleen of snowshoe hares and muskrats were tested by real-time PCR to detect past and active infection to F. tularensis , respectively. Individual host characteristics, including body condition, age, and sex, were evaluated as risk factors of infection, along with ecologic characteristics of the location of capture extracted from geographic databases. Prevalences of antibody to F. tularensis and 95% confidence intervals were 2.9% (1.4-5.1%) in coyotes, 0.6% (0.1-2.1%) in hares, and 0% (0.0-0.9%) in muskrats. Francisella tularensis DNA was not detected by real-time PCR in the pools of four organs from muskrats and hares, but F. tularensis type AI was detected during testing of the individual organs of two antibody-positive hares. Exact logistic regression analyses showed that age was a significant predictor of antibody detection in coyotes, as were the proportion of forest and the proportion of area considered as suitable habitat for hares in the environment around the location of capture of the coyotes. Our results suggest a terrestrial cycle of F. tularensis in the regions studied.

Escherichia coli O121:H19 infection identified on microagglutination assay and PCR.

Non-O157 Shiga toxin-producing Escherichia coli (STEC) strains are increasingly recognized as foodborne pathogens that trigger hemolytic uremic syndrome (HUS). The detection and isolation of these strains is important, but distinguishing their bacteriological profiles is difficult. A 2-year-old girl developed HUS with mild renal involvement 22 days after consuming barbecued meat. Clinical and laboratory findings gradually improved without specific treatment. Because neither enterohemorrhagic E. coli (EHEC) nor Shiga toxins were detected in stool cultures in a clinical laboratory and the patient tested negative for circulating antibodies to O157 lipopolysaccharide, the case was initially diagnosed as probable atypical HUS. Subsequent serodiagnostic microagglutination assay and polymerase chain reaction-based molecular testing, however, indicated the presence of the EHEC O121:H19 strain with stx2. Thus, to correctly diagnose and treat HUS, a system for detecting non-O157 STEC in a clinical setting is urgently needed.

Evaluation of the immunochromatographic (Leptocheck) test for detection of specific antibodies against leptospires.

BACKGROUND: Leptospirosis is a febrile worldwide zoonosis. Routine diagnosis of leptospiral infection is based on demonstration of specific antibodies with serological tests. Performance of the reference serological test, the microscopic agglutination test (MAT), requires significant expertise. The aim of our study was to find out if leptospiral infection can be proven with simple, rapid, commercially available immunochromatographic Leptocheck test in order to introduce it for the first level diagnosis in emergency cases with less specialized laboratory staff. METHODS: In all, 590 serum samples of patients with clinical manifestations suggestive of leptospirosis were collected and tested with MAT and Leptocheck test. For confirmation of the results some other diagnostic methods such as polymerase chain reaction (PCR) and Leptospira isolation were performed. RESULTS: Results of both serological tests were consistent in 576/590 (97.63%) cases but Leptocheck gave more positive results in comparison to MAT (36 and 12, respectively) at first patient's testing. Following up the patient, MAT became positive in majority of Leptocheck positive patients at first visit. Leptospiral DNA was detected in nine blood and six urine samples belonging to thirteen different patients while only two samples were culture positive. CONCLUSION: In comparison with serological tests, PCR and culture have low sensitivity. According to our findings we conclude that Leptocheck test can prove leptospiral infection and could be used for rapid diagnosis of leptospirosis, later the sample should be confirmed with MAT.