A team of researchers from the Universitat Autònoma de Barcelona has demonstrated the efficacy and safety of a synthetic antimicrobial peptide for treating canine leishmaniasis. It is the first time that this type of antibiotic has been demonstrated to be useful against parasitic diseases in real clinical situations. The research is published in the February edition of Antimicrobial Agents and Chemotherapy.

The findings have implications for the prevention and treatment of leishmaniasis in humans. Twelve million people around the world are affected by leishmaniasis; 400 million more are at risk of suffering the disease and every year between 60,000 and 100,000 people die from it. Nearly 2 million new cases are reported every year. The different forms of leishmaniasis are caused by unicellular parasites of the Leishmania genus, which are mainly spread by biting insects, similar to mosquitoes, called phlebotoms. Clinical manifestations range from slight cutaneous lesions to visceral complications that may lead to the individual's death.

Dogs are the main reservoir of the parasite in Spain and in the rest of the Mediterranean basin, the Middle East and South America. Epidemiological studies show that around 70 per cent of dogs in the Mediterranean area are infected. Consequently, eradication of the disease in dogs is considered to be one of the main objectives for improving human health.

The research team at the Universitat Autònoma de Barcelona, headed by Professor Jordi Alberola of the Department of Pharmacology, Therapeutics and Toxicology, worked in collaboration with researchers at the Pompeu Fabra University and the CSIC (Spanish Council for Scientific Research). They demonstrated the safety and efficacy of the acylated synthetic antimicrobial peptide Oct-CA(1-7)M(2-9) against canine leishmaniasis. These latter researchers had already demonstrated the efficacy in laboratory cell cultures, but the efficacy in real clinical situations against parasitic diseases had never been demonstrated.

The researchers have obtained very promising results in a preliminary study on 8 dogs affected by the disease: no adverse affects were detected and the parasitic load decreased. The antibiotic seems to have long term effects, which could be very useful for therapies applied to people or animals that live in areas where medicines cannot easily be shipped to (as is the case in the principal areas affected by leishmaniasis).

One of the most direct applications of the antibiotic would be its use as a drug for treating co-infection of leishmaniasis and HIV. This type of infection affects approximately 10 per cent of people who have AIDS, but in the case of the risk group made up of intravenous drug users it may be as high as 70 per cent.