St. Mary's University
Date of Award
Leptospira interrogans is a pathogenic spirochete that causes the disease known in both the medical and veterinary worlds as Leptospirosis. Canines are commonly infected by leptospires, and in fact, there are vaccines against Leptospirosis for dogs. The canine vaccines against Leptospirosis contain serovars canicola, icterohaemorrhagiae, grippotyphosa, and pomona. Though there is a vaccine against Leptospirosis for humans, as well, it is not widely available. The first vaccines against Leptospirosis contained killed leptospires in a medium partly composed of serum, which often caused undesirable side effects. The vaccine in current use is cultured in a medium that does not contain proteins and therefore, does not cause such severe side effects. However, because the immune response to infection by leptospires is antibody-mediated, it is necessary that the same or an extremely similar serovar to the one that is infecting humans be used in the vaccine, which is difficult to ensure. Leptospirosis is a zoonotic disease in that it is spread to humans by animal carriers. Furthermore, it is currently the most pervasive zoonosis in the world. On the occasion that contact between the two parties is indirect, humans are infected via soil or water that has been contaminated with the urine of infected animal hosts5. Dogs are usually infected via the indirect route. Leptospires enter the body through the mucous membranes of the nose, mouth, and eyes, or through wounds in the skin5. Once they have entered successfully, the leptospires spread throughout the body via the blood vessels. As with most diseases, and especially because Leptospirosis is a disease of the blood, it comes in many forms. Even the symptoms of the mild form of infection are most undesirable. These may include but are not limited to severe headaches that may be related to inflammation of the meninges, stomachaches, muscle aches, chills, redness of the eyes, and skin rash. More serious forms of Leptospirosis can be debilitating, yet it is not financially feasible for all infected humans or dogs to receive necessary 3 treatments. If left untreated, Leptospirosis can lead to organ failure, which may result in a prolonged and painful death. In its more severe forms, Leptospirosis can cause myocarditis, which may lead to heart failure, kidney failure, liver failure, and pulmonary hemorrhage, among other serious possible complications. Leptospirosis has even been known to cause the spontaneous abortion of fetuses in affected pregnant women. Though the disease caused by L. interrogans is well understood, the spirochete’s exact mechanisms of disease relating to virulence factors and implicated proteins are still under continuous research.
Merta, Antonia Michelle, "Characterization of HmuY-Like Heme-Binding Protein of Leptospira interrogans" (2021). Honors Theses. 1.
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