A study by a team of researchers from the United Kingdom, Brazil, and France provides insight into genes that play a role in causing different forms of leishmaniasis and might aid in development of drugs and vaccines (Peacock CS et al. Nat Genet. doi:10.1038/ng2053 [published online ahead of print June 17, 2007]).
At least 20 Leishmania species infect humans, but the factors that underlie different clinical presentations—visceral, cutaneous, and mucocutaneous—are unknown. When the researchers compared the genomes of 3 different species, each of which causes a different form of the disease, they found these related species differed in only 200 of the more than 8000 genes in each genome. This suggests that perhaps only a few species-specific genes are important in determining which form of disease develops after infection, or that the parasite genome plays only a small part in clinical presentation.
Stephenson J. Leishmania. JAMA. 2007;298(3):277. doi:10.1001/jama.298.3.277-b