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Leptospirosis is a zoonotic disease with symptoms in humans and animals, ranging from subclinical to serious and fatal. The disease occurs worldwide, but there is limited recognition of the public and animal health risks it poses in the southern United States. A systematic review of the frequency of animal leptospirosis in 17 states and jurisdictions covering the southern continental United States was performed to advance our understanding of the pathogen's distribution and identify transmission patterns that could be targeted for prevention efforts. Fifty-two articles, spanning >100 years, met the analysis criteria. A wide range of techniques were used to measure seroprevalence and isolate the bacteria. The assessment identified exposure to Leptospira spp and Leptospira spp infection among a diverse range of species, spanning 22 animal families within 14 states, suggesting that the pathogen is distributed throughout the southern region. Disease frequency trends were assessed among animals in various habitats (all habitats, nonwild habitats, and wild habitats). The frequency of Leptospira spp detection in animals in wild habitats increased slightly over time (<0.2%/year). We identified reports of 11 human leptospirosis illness clusters and outbreaks in the southern United States. Exposure to potentially contaminated surface waters were documented for at least seven of the events, and interactions with infected or likely infected animals were documented for at least six of the events. This analysis highlights the need for stronger partnerships across the public and animal health fields to enhance diagnostics, surveillance, and reporting. The early identification of leptospirosis in animals may serve as an indicator of environmental contamination and trigger prevention measures, such as vaccinating companion animals and livestock, use of potable water, and the wearing of waterproof protective clothing near water that may be contaminated. [ABSTRACT FROM AUTHOR]

Since publication of the last consensus statement on leptospirosis in dogs, there has been revision of leptospiral taxonomy and advancements in typing methods, widespread use of new diagnostic tests and vaccines, and improved understanding of the epidemiology and pathophysiology of the disease. Leptospirosis continues to be prevalent in dogs, including in small breed dogs from urban areas, puppies as young as 11 weeks of age, geriatric dogs, dogs in rural areas, and dogs that have been inadequately vaccinated for leptospirosis (including dogs vaccinated with 2-serovar Leptospira vaccines in some regions). In 2021, the American College of Veterinary Internal Medicine (ACVIM) Board of Regents voted to approve the topic for a revised Consensus Statement. After identification of core panelists, a multidisciplinary group of 6 experts from the fields of veterinary medicine, human medicine, and public health was assembled to vote on the recommendations using the Delphi method. A draft was presented at the 2023 ACVIM Forum, and a written draft posted on the ACVIM website for comment by the membership before submission to the editors of the Journal of Veterinary Internal Medicine. This revised document provides guidance for veterinary practitioners on disease in dogs as well as cats. The level of agreement among the 12 voting members (including core panelists) is provided in association with each recommendation. A denominator lower than 12 reflects abstention of ≥1 panelists either because they considered the recommendation to be outside their scope of expertise or because there was a perceived conflict of interest., (© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Leptospirosis is a global zoonotic disease affecting humans and livestock species. Bacterin vaccines lack cross protection between serogroups, and include multiple serovars propagated at 29 °C. Recent work demonstrated substantial variation in the transcriptome of identical species and serovars of Leptospira. Here, substantial differences in protein abundance profiles were identified in Leptospira borgpetersenii serovar Hardjo; strain HB203, which was isolated in the 1980s, compared to newer strains TC129 and TC273 isolated in 2016, and whether they were propagated at the routine temperature of 29 °C, compared to 37 °C which more closely emulates host infection. While 388 and 385 significantly differentially expressed (DE) proteins (FDR of 0.01) were identified in HB203 versus TC129, and HB203 versus TC273 when propagated at 29 °C respectively, only 66 and 4 DE proteins were identified in HB203 versus TC129, and HB203 versus TC273 when propagated at 37 °C respectively. Within each strain comparing temperatures, HB203 had 524 significantly DE proteins, TC129 had 347 DE proteins, and TC273 had 569 DE proteins. Data are available via ProteomeXchange with identifier PXD032831. Results highlight significant differential protein expression among identical serovars of L. borgpetersenii suggesting that bacterin vaccine design can benefit from consideration of strains employed and effects of temperature on growth. Leptospirosis is a zoonotic disease caused by spirochete bacteria of the genus Leptospira. While leptospirosis affects over one million people per year, symptoms range vastly in severity from completely asymptomatic, to flu-like, to multi-organ failure and death in severe cases. Incidental hosts become infected after encountering pathogens directly from contact with another host, including domestic or wildlife animals, or indirectly from contaminated environments. Though animal vaccines exist, they lack cross protection across serogroups, and instead rely on inclusion of multiple carefully selected serovars from laboratory strains prepared at ~29 °C. Recent interest in gene expression at the Leptospira strain level, along with a newly achieved culture temperature of 37 °C (which more closely resembles host body temperature), led us to investigate the proteomic profiles of an older, established challenge strain HB203 in comparison to TC129 and TC273, two strains isolated in 2016 from abattoir cattle in the central United States. Herein, we identify substantial proteomic differences not only between strains of the same species and serovar, but notably between growth temperatures, collectively suggesting that bacterin vaccine composition may benefit from investigating strain selection and the temperature employed for growth of the bacteria used in bacterin preparation. Transmission electron microscopy of a hamster kidney infected with Leptospira borgpetersenii serovar Hardjo strain HB203, representing leptospires in a host environment close to 37 °C. Arrows indicate cross sections of individual leptospires. This study compares the proteomic profile of strains of L. borgpetersenii serovar Hardjo cultured at 37 °C compared to the conventional in vitro growth temperature of 29 °C. [Display omitted] • Differential protein expression by strains of Leptospira borgpetersenii serovar Hardjo • LC/MS/MS of bacterins propagated at 37 °C compared to 29 °C. • Differential expression of bacterial virulence factors at 37 °C and 29 °C [ABSTRACT FROM AUTHOR]

Background Previous studies have reported a seasonal increased risk for leptospirosis, but there is no consistent seasonality reported across regions in the United States. Objectives To evaluate and compare seasonal patterns in seropositivity for leptospirosis in dogs for 4 US regions (northeast [ NE], midwest [ MW], south-central [ SC], and California-southern west coast [ CS]). Animals Forty four thousand nine hundred and sixteen canine serum samples submitted to a commercial laboratory for microscopic agglutination tests ( MAT) from 2000 through 2010. Methods In this retrospective study, positive cases were defined as MAT titers ≥1 : 3,200 for at least one of 7 tested serovars. Four geographic regions were defined, and MAT results were included in regional analyses based on hospital zipcode. A seasonal-trend decomposition method for times series was utilized for the analysis. Monthly variation in the seropositive rate was evaluated using a seasonal cycle subseries plot and logistic regression. Results Two thousand and twelve of 44,916 (4.48%) samples were seropositive. Compared to seropositive rates for February, significantly higher monthly rates occurred during the 2nd half of the year in the MW (OR 3.92-6.35) and NE (OR 2.03-4.80) regions, and only in January (OR 2.34) and December (OR 1.74) in the SC region. Monthly seropositive rates indicative of seasonality were observed earlier in the calendar year for both CS and SC regions. Conclusions and Clinical Importance Seasonal patterns for seropositivity to leptospires differed by geographic region. Although risk of infection in dogs can occur year round, knowledge of seasonal trends can assist veterinarians in formulating differential diagnoses and evaluation of exposure risk. [ABSTRACT FROM AUTHOR]

A waterborne outbreak of leptospirosis occurred among US military personnel during September 1987, on the island of Okinawa, Japan. Micro-agglutination titres for leptospiral antigen of greater than or equal to 200 were detected in hospitalized adult males averaging 22.5 years of age with symptoms compatible with leptospirosis. Epidemiological findings revealed two case clusters distinguished by time and place of exposure. The overall attack rates among recreational swimmers and combat skills training participants were 467/1000 (7/15) and 183/1000 (15/82), respectively. Swallowing of water differentiated individuals with laboratory-confirmed infection from those with no infection, while water immersion alone did not appear to result in leptospiral infection. Additionally, subnormal rainfall may have contributed to the risk of exposure associated with this outbreak.