Seasonal Fluctuations of Incubation, Healing Delays, and Clinical Presentation of Cutaneous Leishmaniasis in French Guiana

Abstract

An investigation was conducted to determine whether seasonal variations affected the development of cutaneous leishmaniasis. Data from 499 cases treated between July 1994 and December 1998 were analyzed. The interval between infection and consultation and between treatment and clinical cure varied significantly between cases with an incubation period during the dry season compared with the rainy season (P < 0.001). When the incubation period occurred during the dry season, the standard pentamidine isethionate treatment seemed to be less effective (i.e.. the odds ratio for failure was 1.9 [1.1-3.4], P = 0.01). The presence of lymphangitis was more frequent during the dry season (i.e., the odds ratio was 0.26 [0.15-0.45], P < 0.001). These results suggested that the observed seasonal variations were due to variations in the host/parasite balance. Converging indirect elements that suggest a role for variations in solar ultraviolet radiation are discussed.

Treatment of leishmaniasis in the Oyapock basin (French Guiana): A K.A.P. survey and analysis of the evolution of phytotherapy knowledge amongst Wayãpi Indians

“…For many respondents, the rainy season was cited as the most conducive period for contracting the disease (40.2%, 53/132), but for 29.6% (39/132), the season has no influence, and a fairly high proportion did not know (18.2%, 24/132). Epidemiological data show that in French Guiana, a peak of contamination occurs in the dry season, and leishmaniasis symptoms appear during the rainy season, from January to May (Nacher et al, 2001;Rotureau et al, 2007).…”

“…The incidence rate is high, particularly in southern French Guiana (the upper and middle Oyapock basin and the upper Maroni basin), ranging between 1 and 10% (Rotureau, 2006). Infection occurs primarily in forested areas at the end of the dry season (Nacher et al, 2001;Rotureau et al, 2006). In the forest, infection is due to sand flies belonging to the Lutzomyia genus, the most frequent being Lutzomyia umbratilis (Rotureau et al, 2007).…”