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Based on morphological variation found in specimens ascribed to Pseudo‐nitzschia pseudodelicatissima and uncertainty regarding the delineation of P. pseudodelicatissima and P. cuspidata, cultures and field material of diatoms in the P. pseudodelicatissima/cuspidata complex were studied in morphological detail. Four different species were identified. The descriptions of the species P. pseudodelicatissima and P. cuspidata were emended on the basis of studies of type material. In addition, P. calliantha sp. nov. and P. caciantha sp. nov. were described as new species based on morphological and molecular data. The morphological differences among the species were found in characters such as width and shape of the valve, density of fibulae and striae, structural pattern of the poroid hymen, and structure of the girdle bands. The morphological studies were supported by phylogenetic analyses of the nuclear‐encoded internal transcribed spacer 1, 5.8S, and internal transcribed spacer 2 rDNA of 24 strains representing 16 different Pseudo‐nitzschia species. The description of the four species helps to explain the variation observed in mating experiments on cultures originally designated as P. pseudodelicatissima. At least two previous reports of toxin production in species identified as P. pseudodelicatissima have been identified as being caused by P. calliantha, and one additional report of toxin production has been identified as either P. pseudodelicatissima or P. cuspidata.

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To estimate the incidence of, identify risk factors for, and describe the clinical presentation of travel-associated African tick bite fever (ATBF), a rapidly emerging disease in travel medicine, we prospectively studied a cohort of 940 travelers to rural sub-Equatorial Africa. Diagnosis was based on suicide polymerase chain reaction and the detection of specific antibodies to Rickettia africae in serum samples by multiple-antigen microimmunofluorescence assay, Western blotting, and cross-adsorption assays. Thirty-eight travelers, 4.0% of the cohort and 26.6% of those reporting flulike symptoms, had ATBF diagnosed. More than 80% of the patients had fever, headache, and/or myalgia, whereas specific clinical features such as inoculation eschars, lymphadenitis, cutaneous rash, and aphthous stomatitis were seen in < or = 50% of patients. Game hunting, travel to southern Africa, and travel during November through April were found to be independent risk factors. Our study suggests that ATBF is not uncommon in travelers to rural sub-Saharan Africa and that many cases have a nonspecific presentation.