The serological and genetic diversity of the Leptospira interrogans Icterohaemorrhagiae serogroup circulating in the UK.

Introduction: Strains of Leptospira interrogans belonging to two very closely related serovars, Icterohaemorrhagiae and Copenhageni, have been associated with disease in mammalian species and are the most frequently reported agents of human leptospirosis. They are considered the most pathogenic serovars and represent more than half of the leptospires encountered in severe human infections. Material and Methods: Nineteen such isolates from the United Kingdom - human, domestic and wildlife species - were typed using three monoclonal antibodies (F12 C3, F70 C14 and F70 C24) in an attempt to elucidate their epidemiology. They were further examined by restriction endonuclease analysis (REA), multiple-locus variable-number tandem repeat analysis (MLVA) and lic12008 gene sequence analysis. Results: Monoclonal antibody F12 C3, which is highly specific for Icterohaemorrhagiae and Copenhageni, confirmed that all the strains belonged to these two serovars. Sixteen strains were identified as Copenhageni and three as Icterohaemorrhagiae serovar. Only one restriction pattern type was identified, thus confirming that REA is not able to discriminate between the Icterohaemorrhagiae and Copenhageni serovars. Variable-number tandem-repeat analysis found three loci with differences in the repeat number, indicating genetic diversity between British isolates. Sequences of the lic12008 gene showed that all isolates identified as the Icterohaemorrhagiae serotype have a single base insertion, in contrast to the same sequences of the Copenhageni serotype. Conclusion: Copenhageni is the predominant serovar in the Icterohaemorrhagiae serogroup isolated in British Isles. There is a genetic diversity of MLVA patterns of the isolates but no genetic tool used in the study was able to determine serovars.

Emerging Infectious Disease Implications of Invasive Mammalian Species: The Greater White-Toothed Shrew (Crocidura russula) Is Associated With a Novel Serovar of Pathogenic Leptospira in Ireland.

The greater white-toothed shrew (Crocidura russula) is an invasive mammalian species that was first recorded in Ireland in 2007. It currently occupies an area of approximately 7,600 km2 on the island. C. russula is normally distributed in Northern Africa and Western Europe, and was previously absent from the British Isles. Whilst invasive species can have dramatic and rapid impacts on faunal and floral communities, they may also be carriers of pathogens facilitating disease transmission in potentially naive populations. Pathogenic leptospires are endemic in Ireland and a significant cause of human and animal disease. From 18 trapped C. russula, 3 isolates of Leptospira were cultured. However, typing of these isolates by standard serological reference methods was negative, and suggested an, as yet, unidentified serovar. Sequence analysis of 16S ribosomal RNA and secY indicated that these novel isolates belong to Leptospira alstonii, a unique pathogenic species of which only 7 isolates have been described to date. Earlier isolations were limited geographically to China, Japan and Malaysia, and this leptospiral species had not previously been cultured from mammals. Restriction enzyme analysis (REA) further confirms the novelty of these strains since no similar patterns were observed with a reference database of leptospires. As with other pathogenic Leptospira species, these isolates contain lipL32 and do not grow in the presence of 8-azagunaine; however no evidence of disease was apparent after experimental infection of hamsters. These isolates are genetically related to L. alstonii but have a novel REA pattern; they represent a new serovar which we designate as serovar Room22. This study demonstrates that invasive mammalian species act as bridge vectors of novel zoonotic pathogens such as Leptospira.

Molecular studies on European equine isolates of Leptospira interrogans serovars Bratislava and Muenchen.

Strains of Leptospira interrogans belonging to two very closely related serovars ­ Bratislava and Muenchen ­ are known to cause widespread infection of the horse population in many parts of the world. Conventional serological typing of isolates has been unable to differentiate between wildlife, pig, dog and possibly horse maintained isolates and therefore has been unable to provide further insight into their diversity and the relationship between them. Twenty-one such European isolates of serovar Bratislava and Muenchen were examined by restriction endonuclease analysis and multiple-locus variable-number tandem repeat analysis in an attempt to elucidate their epidemiology. The restriction pattern types were identified and fell into one of four REA designed pattern types, B1, B2a, M1, M2a. Nine strains from Northern Ireland and two from Germany belonged to B2a, which is a ubiquitous strain being originally isolated from a large number of wild and domestic animal species in the UK. Five strains were identified as B1 and they came from Portugal, The Netherlands, Germany and Northern Ireland; three strains isolated in Germany belong to M1; two strains belonged to M2a. Genotypes B1 and M1 have, with the exception of one hedgehog isolate, been recovered only from horses and it may indicate their adaptation to this species.

Altodouro, a new Leptospira serovar of the Pomona serogroup isolated from rodents in northern Portugal.

A Leptospira strain (designated RIM 139) was isolated from the kidney of a house-mouse, Mus musculus, in Trás-os-Montes e Alto Douro region of northern Portugal. The isolate showed typical leptospiral motility and morphology under dark-field microscopy and was pathogenic for hamsters. Species determination was carried out on basis of PCR products generated by species-specific primers and by sequencing of the secY gene. Putative serogroup typing was performed using the microscopic agglutination test (MAT) with a panel of rabbit anti-Leptospira sera representative of the major pathogenic serogroups. Serovar identification was carried out by a combination of monoclonal antibodies and cross-agglutinin absorption test (CAAT). The novel nature of the strain was confirmed by restriction endonuclease analysis (REA). Results showed that RIM 139 represents a new serovar. The name Altodouro is proposed for this new serovar. Speciation findings - PCR analysis of the ompL1 gene and sequencing of the secY gene - indicated that it belonged to Leptospira kirschneri as did amplification with G1/G2 and B64-I/B64-II the primer sets.