Scientists have taken a new, wide-ranging look at leptospirosis, a zoonotic disease that can cause symptoms ranging from mild headaches to severe bleeding. They sequenced the genomes of different species of leptospira, hoping to figure out what causes some of them to be infectious to humans while others aren’t.
Here’s what lead researcher Dr. Joseph Vinetz of the University of California, San Diego, said about the findings, published in PLOS Neglected Tropical Diseases.
What’s the need for figuring out how the leptospira becomes a pathogen?
We can’t diagnose it in the places most affected by the disease, because there aren’t really any simple tests that are inexpensive enough. The gold standard tests take weeks or even a couple months to get results.
But it’s really treatable — you can treat it with penicillin — so you’d like to be able to make the diagnosis now or within a day or two. But that requires molecular diagnostics which aren’t widely available.
How does it help to sequence all the types of leptospira?
Within the genus, there are 20 species and they’re divided between infectious and non-infectious. We’ve done comparative genome analysis to look for what genes and gene families are present in the infectious leptospira that aren’t present in the non-infectious leptospira.
That shows how bacteria have evolved to adapt to hosts like humans. It also shows how difficult vaccine development can be, because of that diversity. If you’re in Brazil, different parts of Brazil have different types of leptospira, and we can take these differences into account now in terms of vaccine development research.
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