Eschar-associated spotted fever rickettsiosis, Bahia, Brazil

Abstract

In Brazil, Brazilian spotted fever was once considered the only tick-borne rickettsial disease. We report eschar-associated rickettsial disease that occurred after a tick bite. The etiologic agent is most related to Rickettsia parkeri, R. africae, and R. sibirica and probably widely distributed from Sao Paulo to Bahia in the Atlantic Forest.

Figure 1

Lesions on day 6 of illness of patient with eschar-associated rickettsial disease, Bahia, Brazil, 2007. A) Eschar on right wrist; B) papular skin rash on left elbow; C) ulcerated lesion on lower lip; D) erosions on tongue mucosa; E) vesicular papular lesions on trunk.

Figure 2

Genetic relationships of the spotted fever group rickettsiae (SFGR) detected in tissue of patient with eschar-associated rickettsial disease, Bahia, Brazil, 2007. Sequence comparison was conducted with MEGA version 4 (www.megasoftware.net). The phylogenetic optimal tree was inferred by using the neighbor-joining method, and distances were evaluated by implementing the Kimura 2-parameter model of substitution (sum of branch length = 0.58588522). In total, 323 nt sites of gltA and 401 nt sites of ompA were concatenated and evaluated; primer sequences and sites containing gaps and deletions were excluded from the analysis. Statistical reliability of the tree is based on 1,000 bootstrap replicates; only bootstrap values >50 are shown above the branches. The corresponding sequences of reference species and isolates were obtained from the National Center for Biotechnology Information GenBank database. A) Genetic association of Rickettsia sp. Bahia and other previously characterized SFGR; B) expanded tree of relationships among new SFGR to R. africae, R. parkeri, R. sibirica, Rickettsia sp. S and Atlantic Forest. Scale bars indicate nucleotide substitutions per site.