Laboratory Diagnosis

Although new, improved diagnostic methods are badly needed and are being developed, the diagnosis of cyclosporiasis is best made using direct acid-fast stain (or microwave-heated safranin staining) of fecal specimens (Long et al., 1990, 1991; Visvesvara et al., 1997). A major limitation is the difficulty detecting infectious oocysts in contaminated food or water in the concentration that are actually infectious for humans. Indeed, the most sensitive test at present may well be consumption by humans who, if not apparently immune, are susceptible to disease from subdetectable numbers of parasites. With the development of immunologic and gene probe reagents, we can expect the diagnosis of Cyclo-spora infections and contamination to improve considerably. PCR, with RFLP of amplification products, is able to identify as few as 10-25 oocysts of Eimeria tenella and Cyclospora caye-tanensis directly from raspberries (Jinneman et al., 1998).

Table 7.2 Trimethoprim-sulfamethoxazole (TXS) for


43 HIV + ve patients in Haiti; 11% of 450 with diarrhea (vs. 30% with Cryptosporidium; 12% with Isospora belli;

3% Giardia lamblia; 1% Entamoeba histolytica) TXS q.i.d. x 10 days 100% responded (diarrhea and stool positivity) by 2.5 days 43% relapsed in 1 month (all responded again) suppressed with TXS 3/week in 11/12 (x7 months) (Pape et al., 1994)

21 Kathmandu expatriates with TXS b.i.d. x7 days eradicated Cyclospora in 29% at 3 days, 94% at 7 days v.s. 19 double-blind placebo controls (0 at 3 days; 12% at 7 days)

p<0.02 and 0.0001; no relapses 7 days after (Hoge et al., 1995)

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