Widespread Availability of Artemisinin Monotherapy in the United States

To the Editor: Artemisinin-based combination therapies are recommended as first line treatments for Plasmodium falciparum malaria in most areas of the world. The article by Shahinas et al. (1) describes a patient who had P. falciparum malaria after returning from Nigeria. Her isolate had an elevated 50% inhibitory concentration to artemisinin derivatives. She had obtained artesunate in Nigeria and took it weekly for malaria prophylaxis, which might have contributed to the relative resistance found.

horses and 1 from Cx. tarsalis mosquitoes. Notably, our sequence is distantly related to GQ287646, which was isolated from Culex spp. mosquitoes in Chaco, Argentina. The nucleotide sequence of the positive control VEEV-Tc83 is correctly placed in the VEEV clade.
Clinical and laboratory fi ndings showed that the illness described here was compatible with viral encephalitis. Using a generic RT-PCR assay on an early CSF sample, we amplifi ed a partial sequence (NSP4 gene) of an alphavirus. Phylogenetic analyses showed that the patient's sequence grouped with sequences from WEEV, with high statistical support. A second RT-PCR assay on the NSP1 gene enabled us to obtain an amplifi cation of 208 bp, which is consistent with the expected size for WEEV. Therefore, we concluded that the fatal disease was likely caused by WEEV. Since the 1970s, to our knowledge, the presence of WEEV (or other alphaviruses) in Uruguay has not been documented. Moreover, no recent reports have been made of genome detection of WEEV in encephalitis cases in the region.
Although the case described here may be rare, the etiology of many viral encephalitides in Uruguay remains unknown. Serologic studies in horses and studies to detect arboviruses in mosquito populations are being conducted to investigate the status of arbovirus infections in Uruguay.

Availability of Artemisinin Monotherapy in the United States
To the Editor: Artemisininbased combination therapies are recommended as fi rst line treatments for Plasmodium falciparum malaria in most areas of the world. The article by Shahinas et al. (1) describes a patient who had P. falciparum malaria after returning from Nigeria. Her isolate had an elevated 50% inhibitory concentration to artemisinin derivatives. She had obtained artesunate in Nigeria and took it weekly for malaria prophylaxis, which might have contributed to the relative resistance found.
In 2009, one artemisinin-based combination therapy (artemether/ lumefantrine) became available for use in the United States. However, it is not widely appreciated that artemisinin is actually available in the United States as an herbal supplement for over-thecounter purchase (2). It is marketed for general health maintenance and for treatment of parasitic infections and cancers (Figure), although as with other supplements it is not intended to diagnose, treat, cure, or prevent any disease. As in the patient described by Shahinas et al., widespread use of artemisinin or its derivatives as monotherapies could potentially lead to progressively increasing resistance in P. falciparum malaria (3). Studies in western Cambodia, where artemisinin monotherapy has been available for many years, have revealed in vivo artesunate resistance, with markedly decreased parasite clearance times (3). Progressive spread of artemisinin resistance could have disastrous consequences for the global control of malaria. Thus, minimally regulated use of potent compounds in dietary supplements has the potential for major public health implications.  (1). This observation was unexpected because previous data from multispacer sequence typing and glp D gene sequencing yielded only the Orientalis biotype in cases of ancient plague (2).

Robert M. Rakita and Uma Malhotra
Using suicide PCR (3), we therefore further investigated pPCP1 in 10 negative control dental pulp specimens and 60 specimens collected from 1 Justinian Orientalis plague site (2), 2 Black Death Orientalis sites, and 2 additional medieval plague sites. All negative controls remained negative; 14 (23%) of 60 plague specimens yielded a PCR product, and 7 interpretable sequences yielded a 3-T homopolymeric tract in all cases.
We further tested a Y. pestis isolate collection comprising 2 Antiqua, 6 Medievalis, and 4 Orientalis strains. No amplifi cation was obtained in DNA-free PCR mix and 5 Y. enterocolitica-negative control isolates, whereas sequencing yielded a 3-T homopolymeric tract in all 12 Y. pestis isolates.
BLAST analysis (http://blast. ncbi.nlm.nih.gov/blast.cgi) indicated that the 5-T homopolymeric tract has been found only once in the Y. pestis CO92 strain (4) and in none of 22 modern and 11 ancient sequences (Table). This 5-T homopolymeric tract is therefore CO92 strain specifi c and not a marker for the Orientalis biotype. This pPCP1 plasmid sequence, located into a noncoding region of the 3′ extremity of the plasmid, is characterized by several homopolymeric tracts of poly (A) and poly (T), including the 1 herein investigated. Instability of the T-stretches has been reported in bacterial genomes (5) as being hot spots for mutations (5).
Therefore, in our assessment, the data reported for the late medieval Bavaria burial (1) do not support that deaths of persons buried in this site resulted from a non-Orientalis plague. Typing modern or ancient Y. pestis strains should not rely on poly (A) and poly (T) homopolymeric tracts sequencing.