New Species found that causes Leptospirosis

Leptospirosis is an acute infectious disease caused by bacterial spirochetes of the genus Leptospira. An article published in the open-access journal PLoS Neglected Tropical Diseases reports that a new species of Leptospira has been identified in the highly biodiverse Peruvian Amazon region. Researcher Michael A. Matthias (Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine) and colleagues found that the domestic rat is the animal source of this species, and they demonstrated how the disease was identified in patients in Iquitos, Peru by modifying the diagnostic routines to include the new species.

Leptospirosis is especially common in low-income areas with poor sanitation and contaminated water. The Amazon region of Iquitos, with its diverse animal population, tropical weather, and lack of sufficient sanitation, is a model ecological setting for maintaining and transmitting leptospirosis. Although the infectious disease has become globally important (not isolated to the Amazon), the difficulties involved in its diagnosis interfere with the ability to gage the precise public health impact.

The researchers provisionally named the new species Leptospira licerasiae after isolating and identifying it. They then included the new isolate when testing the blood of patients with acute febrile illness (fever fits) in Iquitos, Peru. Finding a much higher incidence of leptospirosis than expected, the authors demonstrate the importance of diagnosing with region-specific Leptospira.

The authors conclude: "Based on serological data that take advantage of its antigenic uniqueness, 'Leptospira licerasiae' serovar Varillal appears to be an important cause of leptospirosis in the Peruvian Amazon region, but is uncommon elsewhere in Peru. The peridomestic rat is likely the major reservoir of this new species. Elucidation of virulence differences between pathogenic and intermediate leptospires will provide insight into leptospiral evolution and disease mechanisms, and may contribute to the control and amelioration of leptospirosis in the developing world."

See Full Article