McArthur revisited: fluorescence microscopes for field diagnostics

Department of Experimental Orthopaedics and Biomechanics, Philipps University, Baldingerst, 35033 Marburg, Germany.
Trends in Parasitology (Impact Factor: 6.2). 10/2007; 23(10):468-9. DOI: 10.1016/
Source: PubMed


Few scientific instruments become eponymous with their inventors. Among those that have is the 'McArthur'. As a student in the 1930s, John Norris McArthur wanted a portable microscope to take on field trips. His rugged pocket field microscope [Mcarthur, J. (1958) A new concept in microscope design for tropical medicine. Am. J. Trop. Med. Hyg. 7, 382-385] remains a classic of compact design and performance, and has been used for malaria diagnosis over several decades. The 'McArthur' has dimensions of 102x63x51mm (McArthur folded the 160mm path length with a prism) and uses phase-contrast and specialised oil immersion objective lenses. Later, a plastic version was developed and further adapted for the Open University by Kirk & Sons, UK [McArthur J. (1971) The McArthur microscope--open university model. Trans. R. Soc. Trop. Med. Hyg. 65, 438].

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By 1999, 20-30% of patients treated in Omugo, NW Uganda were failing to respond to melarsoprol. PCR/RFLP analysis indicated that mutant alleles accounted for 58.5% of those in circulation. Melarsoprol was withdrawn in 2001 and by 2003 mutant TbAT1 alleles accounted for only 14% of those in circulation in NW Uganda. The current study aimed to determine the incidence of the PCR/Sfa NI TbAT1 mutant alleles in 2006, some five years after melarsoprol had been withdrawn as first-line treatment. Successful molecular analysis of 91 of 132 (68.9%) T. b. gambiense field isolates from Omugo and Moyo in NW Uganda indicated the presence of only TbAT1 wild type alleles. Mutant alleles thus appear to have disappeared. This may be the result of parasite fitness cost following the withdrawal of melarsoprol as a stage II first-line drug from Omugo health centre, Arua, since 2001. 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