Leptospirosis and its Epidemiology

Leptospirosis has been known to affect both man and numerous mammalian species resulting in morbidity and mortality. Leptospira interrogans is a pathogenic species that cause leptospirosis while L. biflexa is nonpathogenic. Leptospirosis has worldwide distribution due to the large spectrum of mammalian hosts that harbor and excrete the agent from their renal tubules. The central point on the epidemiology of leptospirosis is the state of the renal carrier, the animal that has its renal tubules colonized by leptospirae, which in turn are excreted in the urine infecting the environment. Infection in domestic animals and wildlife can lead to economic loss and pose a potential spread to the communities. The disease can be directly transmitted through contact with secretions, blood or urine of infected animals, or indirectly through water contaminated mainly with urine of reservoir animals. Leptospirae penetrate intact mucous membrane of the mouth, nose or eyes or abraded, scratched or water softened skin and multiply rapidly after entering the vascular system, spread and further replicate in many tissues including kidney, liver, spleen, central nervous system, eye and genital tract. In Ethiopia leptospirosis is a relatively unknown disease although already reported to occur in domestic animals. The disease is characterized by a broad range of clinical signs which can be presented as acute, sub-acute or chronic. Leptospirosis can be treated by antibiotics such as tetracycline, penicillin, doxycycline, streptomycin and erythromycin, while prevention is characterized by sanitary control and decrease in the risk of infection occurring due to contact with contaminated environments, infected wild animals as well as with synanthropic animals and rodents. Elimination of the carrier state, control of rodents in kennels, maintenance of environmental condition to discourage bacterial survival and isolation of infected animal need to be under taken in order to prevent the disease. Leptospirosis has been recognized as a re-emerging global public health problem due to the increased incidence in both developing and developed countries.