Canine leishmaniosis is endemic in more than 70 countries in the world. It can be found in regions of southern Europe (), Africa, Asia, South and Central America and has recently emerged in the USA. Canine leishmaniosis is also an important concern in non-endemic countries where the imported disease may constitutes a veterinary and public health problem.
Seroprevalence rates found in studies carried out in the Mediterranean basin range between 10 and 37%, and 70% by using the PCR method for detecting Leishmanial DNA. Based on the seroprevalence data it has been estimated that 2.5 million dogs in France, Italy, Portugal and Spain are infected. The number of infected dogs in south America is also estimated in millions with high infection rates in some areas of Brazil and Venezuela.
Human visceral leishmaniosis (VL)
Although transmission of Leishmania infantum is the predominant cause of human VL in the Mediterranean basin, infection with L. donovani, is responsible for a large part of fatalities in humans. Worldwide, there are approximately 500,000 new cases of visceral leishmaniosis annually.
Human VL is concentrated in Eastern Africa (particularly Sudan and Kenya), and on the Indian subcontinent (Bangladesh, North-east India and Nepal). Infantile VL is found in the Mediterranean basin, extending east through South-west Asia to China, and west to Central and South America. Particularly in North-east Brazil more than 90% of all the cases in Latin America are found. The infantile type has been recognized to expand to infect immunocompromised adults either suffering from HIV infection or any other type of immunosuppression.
Human CL in the Old World is mainly found in arid or semi-arid areas. The anthroponotic type is usually found as epidemics in densely populated cities of central and west Asia. The zoonotic form is characteristic of semidesert areas in Asia and North Africa, associated with colonies of reservoir hosts.
Urbanization due to ecological, demographic and environmental changes appears to be one of the major worldwide risk factors for leishmaniosis and largely contributes to the persistence of the burden of the disease, especially in anthroponotic foci. It affects all four eco-epidemiological entities (cutaneous vs. visceral, anthroponotic vs. zoonotic).