Leptospira: A genus of aerobic, helical spirochetes, some species of which are pathogenic, others free-living or saprophytic.Leptospira interrogans: A genus of question mark-shaped bacteria spirochetes which is found in fresh water that is contaminated by animal urine. It causes LEPTOSPIROSIS.Leptospirosis: Infections with bacteria of the genus LEPTOSPIRA.Leptospira interrogans serovar icterohaemorrhagiae: A serovar of the bacterial species LEPTOSPIRA INTERROGANS, whose primary host is RATS.Leptospira interrogans serovar canicola: A serovar of the bacterial species LEPTOSPIRA INTERROGANS, whose natural host is DOGS where disease is characterized by GASTROENTERITIS, and INTERSTITIAL NEPHRITIS.Weil Disease: A severe form of LEPTOSPIROSIS, usually caused by LEPTOSPIRA INTERROGANS SEROVAR ICTEROHAEMORRHAGIAE and occasionally other serovars. It is transmitted to humans by the rat and is characterized by hemorrhagic and renal symptoms with accompanying JAUNDICE.Agglutination Tests: Tests that are dependent on the clumping of cells, microorganisms, or particles when mixed with specific antiserum. (From Stedman, 26th ed)Leptospira interrogans serovar australis: A serovar of the bacterial species LEPTOSPIRA INTERROGANS, characteristically associated with a severe zoonotic disease in humans.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Mesocricetus: A genus of the family Muridae having three species. The present domesticated strains were developed from individuals brought from Syria. They are widely used in biomedical research.Serotyping: Process of determining and distinguishing species of bacteria or viruses based on antigens they share.Horse Diseases: Diseases of domestic and wild horses of the species Equus caballus.Leptospira interrogans serovar autumnalis: A serovar of the bacterial species LEPTOSPIRA INTERROGANS, whose primary host is the MOUSE.Comoros: A group of Indian Ocean Islands, the islands of Great Comoro, Anjouan, Mayotte, and Moheli, lying between northeast Mozambique and northwest Madagascar. The capital is Moroni. In 1914 they became a colony attached to Madagascar administratively and were made a French overseas territory in 1947. Except for Mayotte which remained French, Comoros became an independent republic in 1975. Comoros represents the Arabic qamar, moon, said by some scholars to be linked with the mystical Mountains of the Moon said to be somewhere in equatorial Africa. (From Webster's New Geographical Dictionary, 1988, p283 & Room, Brewer's Dictionary of Names, 1992, p122)Murinae: A subfamily in the family MURIDAE, comprising the Old World MICE and RATS.Floods: Sudden onset water phenomena with different speed of occurrence. These include flash floods, seasonal river floods, and coastal floods, associated with CYCLONIC STORMS; TIDALWAVES; and storm surges.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.Abortion, Veterinary: Premature expulsion of the FETUS in animals.Disease Reservoirs: Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (DISEASE VECTORS) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks.Bacterial Outer Membrane Proteins: Proteins isolated from the outer membrane of Gram-negative bacteria.Rodent Diseases: Diseases of rodents of the order RODENTIA. This term includes diseases of Sciuridae (squirrels), Geomyidae (gophers), Heteromyidae (pouched mice), Castoridae (beavers), Cricetidae (rats and mice), Muridae (Old World rats and mice), Erethizontidae (porcupines), and Caviidae (guinea pigs).Spirochaeta: A genus of flexible, spiral rods found in hydrogen sulfide-containing mud, sewage, and polluted water. None of the species properly referred to in this genus are pathogenic.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Cattle Diseases: Diseases of domestic cattle of the genus Bos. It includes diseases of cows, yaks, and zebus.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Leptospira interrogans serovar hebdomadis: A serovar of the bacterial species LEPTOSPIRA INTERROGANS, whose frequent host is CATTLE.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Spirochaetales: An order of slender, flexuous, helically coiled bacteria, with one or more complete turns in the helix.Horses: Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.Bacterial Vaccines: Suspensions of attenuated or killed bacteria administered for the prevention or treatment of infectious bacterial disease.