LEPTOSPIROSIS

LEPTOSPIROSIS


Leptospirosis is considered one of the most common zoonotic diseases in the world. In humans, it is also known as Weil’s disease, swineherd’s disease, rice-field disease, swamp fever, and mud fever. In horses, it can cause a condition known as periodic ophthalmia, or moon blindness. In dogs it is known as canicola disease.



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ETIOLOGY: BACTERIAL


Leptospirosis is caused by bacteria that belong to the genus Leptospira. All Leptospira are spirochetes (slender, spiral, motile bacteria) that coil around a central axis. They are aerobic gram-negative organisms. They are motile because they are flexible and able to bend and wriggle. They prefer to live in an alkaline environment.


There are two species of Leptospira recognized today: L. interrogans and L. biflexa. L. interrogans is pathogenic to humans and animals. L. biflexa is nonpathogenic and is free-living in water. L. interrogans has over 200 different strains, or serovars (species variants), some of which are host-species specific and others that can infect a variety of host species. All of the serovars look identical. Each serovar has a particular host species it prefers, but some of the serovars will infect other species, too. For example, L. interrogans serovar canicola is found primarily in dogs but will also infect cattle.



HOSTS


Over 160 mammalian species, including humans, have been identified as susceptible to leptospirosis.



TRANSMISSION


Leptospira organisms are passed in the urine of an infected host and are transmitted to another host through mucous membranes and skin lesions. Transmission may occur through exposure to water, soil, or food that has been contaminated with infected urine. The most common mode of transmission is by drinking contaminated water. Catching and eating infected rodents and eating grass and food contaminated with urine are other common modes of transmission among animals. Animals and humans can become infected by touching placentas, aborted fetuses, and related tissues (Figure 23).


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FIGURE 23 Leptospirosis.


When the organism enters the host’s body, it enters the blood stream and is distributed throughout the body. Organisms are found in all tissues initially, but eventually primarily in the kidney, liver, spleen, respiratory tract, central nervous system, eyes, and genital tract, where they live and reproduce. Wherever the organism is found, it causes blood vessel damage, primarily in capillaries. Eventually, the organism will be removed from most organs by the host’s immune system, but some organisms may remain in the kidneys, eyes, central nervous system, and genital tract and continue reproducing. As in other organs, the capillaries in the kidney are damaged, so blood leaks into the urine and the host passes bloody urine. The liver is the second most commonly affected organ. Liver damage is characterized by jaundice (yellowing of skin and mucous membranes).

Related posts:

  1. ABOUT THE DISEASES
  2. CAMPYLOBACTERIOSIS (VIBRIOSIS)
  3. MYCOBACTERIUM INFECTIONS (TUBERCULOSIS)
  4. PSITTACOSIS

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Oct 1, 2016 | Posted by in EXOTIC, WILD, ZOO | Comments Off on LEPTOSPIROSIS

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