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Leptospirosis is a global neglected zoonosis, responsible for at least 1 million cases per year and almost 60 thousand deaths. The disease is caused by pathogenic and virulent bacteria of the genus Leptospira, either by direct contact with the bacteria or indirectly by exposure to contaminated water or soil. Domestic and wild animals act as reservoir hosts of infection, shedding leptospires from colonized renal tubules of the kidney, via urine, into the environment. The generation of mutant strains of Leptospira is critical to evaluate and understand pathogenic mechanisms of infection. CRISPR interference (CRISPRi) has proven to be a straightforward, affordable, and specific tool for gene silencing in pathogenic Leptospira. Therefore, the methodological details of obtaining the plasmid constructs containing both dCas9 and guide RNA, delivery of plasmids to Leptospira by conjugation with the E. coli strain β2163, and transconjugant recovery and evaluation, will be described. In addition, the recently described Hornsby-Alt-Nally (HAN) media allows for the relatively rapid isolation and selection of mutant colonies on agar plates.

Leptospirosis is a neglected zoonosis of global importance with a complex epidemiology that affects humans, domestic and wild mammals. However, due to the diversity of clinical signs and difficulties of establishing a confirmatory laboratory diagnosis, the disease remains poorly investigated, particularly in the developing world. In Morocco, a descriptive study of the seroprevalence of Leptospira infection in animals has never been undertaken. To fill this gap, the current study was conducted on a subset of animals in north-west Morocco as a preliminary step towards understanding the epidemiological patterns of animal leptospirosis in the country. The study was conducted on 289 serum samples collected between January and April 2012 from dogs, cattle, sheep, goats and donkeys in the areas of Rabat-Temara, Sidi Kacem and Oulmes. All serum samples were tested by the MAT with 14 reference strains of the most prevalent pathogenic serovars of Leptospira and two serovars of non-pathogenic Leptospira. The overall seroprevalence of Leptospira in cattle, sheep, goats, dogs and donkeys was 15%, 18%, 20%, 21% and 20%, respectively. The most prevalent serogroups found in each species were Ballum, Sejroe, and Australis in cattle, Ballum, Australis and Sejroe in sheep, Australis and Ballum in goats, Javanica and Australis in donkey and Australis, Ballum and Canicola in dogs. Of all the serogroups tested in this study, Icterohaemorrhagiae, the only serogroup which has been previously reported in humans in Morocco, was rarely reactive. The majority of reactive sera were collected from low land areas. A large number of sera samples classified as seronegative when tested against pathogenic leptospires were positive when tested against non-pathogenic leptospires; this is suggestive of possible novel, as yet unclassified, Leptospira serovars in Morocco. Eleven of thirteen sheep urine samples were positive by real-time PCR confirming their role as Leptospira carriers in Morocco., (© 2014 Blackwell Verlag GmbH.)

A total of 474 serum samples from client owned Irish dogs were tested for the presence of antibodies to serovars Canicola, Icterohaemorrhagiae, Bratislava, Autumnalis, Pomona, Altodouro, Grippotyphosa, Mozdok, Hardjobovis and Ballum. Six per cent of dogs presented to veterinary practitioners for problems unrelated to leptospirosis showed evidence of prior exposure to leptospiral serovars belonging to the serogropus Ballum, Australis, Pomona and Sejroe. One unvaccinated dog suspected to have leptospirosis showed seroconversion to serogroup Icterohaemorrhagiae. Based on these results the authors conclude that canine exposure to serogroup Ballum should be monitored because dogs may serve as sentinels for this serovar in the environment. Vaccination with multivalent vaccines containing serovar Bratislava in addition to serogroups Icterohaemorrhagiae and Canicola is advisable., (British Veterinary Association.)

Leptospirosis is a zoonotic disease with a worldwide distribution affecting most mammalian species. Clinical leptospirosis is common in dogs but appears to be rare in cats. Both dogs and cats, however, can shed leptospires in the urine. This is problematic as it can lead to exposure of humans. The control of leptospirosis, therefore, is important not only from an animal but also from a public health perspective. The aim of this consensus statement is to raise awareness of leptospirosis and to outline the current knowledge on the epidemiology, clinical features, diagnostic tools, prevention and treatment measures relevant to canine and feline leptospirosis in Europe., (© 2015 British Small Animal Veterinary Association.)

Leptospirosis is a global zoonotic disease. Pathogenic Leptospira species, the causative agent of leptospirosis, colonize the renal tubules of chronically infected maintenance hosts such as dogs, rats and cattle. Maintenance hosts typically remain clinically asymptomatic and shed leptospires into the environment via urine. In contrast, accidental hosts such as humans can suffer severe acute forms of the disease. Infection results from direct contact with infected urine or indirectly, through contaminated water sources. In this study, a quantitative real-time PCR specific for lipL32 was designed to detect the urinary shedding of leptospires from dogs. The sensitivity and specificity of the assay was evaluated using both a panel of pathogenic Leptospira species and clinical microbial isolates, and samples of urine collected from experimentally infected rats and non-infected controls. The lower limit of detection was approximately 3 genome equivalents per reaction. The assay was applied to canine urine samples collected from local dog sanctuaries and the University Veterinary Hospital (UVH) at University College Dublin. Of 525 canine urine samples assayed, 37 were positive, indicating a prevalence of urinary shedding of leptospires of 7.05%. These results highlight the need to provide effective canine vaccination strategies and raise public health awareness.

Summary Rats, dogs, cattle, bats and sea lions, exemplify the diversity of mammalian species that can facilitate transmission of the zoonotic disease leptospirosis. The causative agent, pathogenic species of Leptospira, is shed in urine of chronically infected hosts. Direct contact with infected urine, or indirectly with water sources contaminated with infected urine, poses a risk of infection for humans exposed during water-related recreational and occupational activities. New serovars of Leptospira and maintenance hosts continue to be identified. In the western world, incidences of recreational exposure are increasing, while incidences of occupational exposure are decreasing. Adventure travellers returning from tropical regions, are presenting at clinics with symptoms of leptospirosis following participation in high risk activities including white water rafting, triathlons, endurance races and caving. Risks of infection can be reduced with increased awareness of how the disease is contracted, by avoiding contact with high risk water sources and the use of prophylaxis during high risk activities. Molecular techniques can be used to provide risk assessments prior to competition, to supplement epidemiology, and to assess shedding of Leptospira in urine samples.

Pathogenic species of Leptospira cause leptospirosis, a global zoonotic disease. Leptospira colonize renal tubules of chronically infected maintenance hosts, from where they are shed in urine to the environment and survive in suitable moist conditions. Transmission of disease to new hosts is facilitated by contact with contaminated urine or water sources, because Leptospira can penetrate broken skin or mucosal surfaces of new hosts. Infection of new hosts may be asymptomatic, as with chronically infected maintenance hosts, or may result in an acute disease process in which clinical signs can include fever, jaundice, renal failure, and pulmonary hemorrhage. Those factors that determine if an animal will suffer an acute or a chronic infection are not fully understood but include host animal species, infecting serovar, and infecting dose. During chronic infection, renal colonization and leptospiruria persist despite cellular and humoral responses by the host. Tubulointerstitial nephritis is the most common lesion associated with chronic infection, and this may progress to fibrosis and subsequent renal failure. This review aims to address how Leptospira cause tubulointerstitial nephritis during chronic leptospirosis and to summarize the mechanisms by which Leptospira might evade host immune responses during chronic colonization of the renal tubule.