Coccidial Infections in Patients Evaluated for Diarrhea
Coccidial Infections in Patients Evaluated for Diarrhea
From March to September 2001, 315 specimens from "nonrepeat" patients that were submitted for ova and parasite examination were stained using the Kinyoun modified acid-fast stain to detect the intestinal coccidians. Four patients (1.3%) were infected with coccidians, 2 with Cryptosporidium parvum and 2 with Cyclospora cayetanensis. No infections with Isospora belli were detected. In comparison, 15 patients (4.8%) had infections with one or more intestinal parasites detected by routine trichrome staining: 5 had Giardia lamblia; 2, Dientamoeba fragilis; 3, Strongyloides stercoralis; 1, Iodamoeba bütschlii; 3, Endolimax nana; 6, Blastocystis hominis; and 1, Entamoeba coli. Four patients were multiply infected. Coccidians made up 29% of the clinically significant parasitic infections. The coccidians were missed in all 4 cases because no special staining was ordered. Clinicians need to be reminded that additional tests should be ordered to fully evaluate patients with chronic diarrhea in which no diagnosis is found by routine testing.
The intestinal coccidians, Cryptosporidium parvum, Cyclospora cayetanensis, and Isospora belli, are associated with gastrointestinal disease in humans. Although the first outbreak of well water-acquired cryptosporidiosis in the United States was seen in Texas in 1983, the most widely recognized outbreak occurred a decade later in 1993 in association with contamination of a municipal water source with Cryptosporidium oocysts originating from cattle. An estimated 403,000 immunocompromised and immunocompetent people were infected with this organism. Since that time, outbreaks have been linked to contaminated drinking and recreational water. Disease transmission also has been described via consumption of unpasteurized apple cider and through person-to-person contact. C parvum produces a diarrheal syndrome with profuse, watery diarrhea and disease manifestations that tend to be most severe and protracted and more common in immunocompromised patients, in whom it can produce extreme weight loss and wasting.
C cayetanensis was first described as causing prolonged, watery diarrhea in humans in 1977. Although the disease occurrence is predominantly tropical and subtropical, it is seen worldwide, usually associated with importation of con-taminated food products or contaminated water sources. Outbreaks of diarrheal disease in humans have been linked to the consumption of Guatemalan raspberries, basil, a variety of green leafy vegetables, and Asian freshwater clams. Although most cases reported in the literature represent healthy hosts, illness with the organism also is seen in immunocompromised populations.
I belli is an uncommon human pathogen, linked most commonly to the handling of contaminated cat feces. This organism can cause disease in immunocompetent and immunocompromised hosts, often producing prolonged, profuse, watery diarrhea; anorexia; weight loss; and fever. It has emerged as a significant cause of protracted diarrhea in patients with AIDS in Haiti and, to a lesser extent, in the United States.
Every year, thousands of patients examined at the University of Kentucky, Lexington, are evaluated for diarrheal syndromes. Bacterial cultures remain the first line of diagnosis for acute illnesses, while parasitic infections generally are considered in patients with chronic symptoms and those with appropriate travel histories or other risk factors. Most intestinal parasites can be detected with the combination of a formalin-ethyl acetate concentrate and standard trichrome stain. Wet preparations and trichrome stains do not adequately detect the coccidian organisms, C cayetanensis, C parvum, and I belli. Identification of these organisms requires special staining techniques. The modified acid-fast stain may be used to detect the oocysts of all of these coccidian organisms. The size distribution of the modified acid fast-staining oocysts, together with their overall morphologic features, permits differentiation of these organisms. We used the Kinyoun modified acid-fast stain to perform a point prevalence assessment of these coccidian diseases in patients being evaluated for diarrhea with examination for ova and parasites (O&P) during a 7-month period in central Kentucky.
From March to September 2001, 315 specimens from "nonrepeat" patients that were submitted for ova and parasite examination were stained using the Kinyoun modified acid-fast stain to detect the intestinal coccidians. Four patients (1.3%) were infected with coccidians, 2 with Cryptosporidium parvum and 2 with Cyclospora cayetanensis. No infections with Isospora belli were detected. In comparison, 15 patients (4.8%) had infections with one or more intestinal parasites detected by routine trichrome staining: 5 had Giardia lamblia; 2, Dientamoeba fragilis; 3, Strongyloides stercoralis; 1, Iodamoeba bütschlii; 3, Endolimax nana; 6, Blastocystis hominis; and 1, Entamoeba coli. Four patients were multiply infected. Coccidians made up 29% of the clinically significant parasitic infections. The coccidians were missed in all 4 cases because no special staining was ordered. Clinicians need to be reminded that additional tests should be ordered to fully evaluate patients with chronic diarrhea in which no diagnosis is found by routine testing.
The intestinal coccidians, Cryptosporidium parvum, Cyclospora cayetanensis, and Isospora belli, are associated with gastrointestinal disease in humans. Although the first outbreak of well water-acquired cryptosporidiosis in the United States was seen in Texas in 1983, the most widely recognized outbreak occurred a decade later in 1993 in association with contamination of a municipal water source with Cryptosporidium oocysts originating from cattle. An estimated 403,000 immunocompromised and immunocompetent people were infected with this organism. Since that time, outbreaks have been linked to contaminated drinking and recreational water. Disease transmission also has been described via consumption of unpasteurized apple cider and through person-to-person contact. C parvum produces a diarrheal syndrome with profuse, watery diarrhea and disease manifestations that tend to be most severe and protracted and more common in immunocompromised patients, in whom it can produce extreme weight loss and wasting.
C cayetanensis was first described as causing prolonged, watery diarrhea in humans in 1977. Although the disease occurrence is predominantly tropical and subtropical, it is seen worldwide, usually associated with importation of con-taminated food products or contaminated water sources. Outbreaks of diarrheal disease in humans have been linked to the consumption of Guatemalan raspberries, basil, a variety of green leafy vegetables, and Asian freshwater clams. Although most cases reported in the literature represent healthy hosts, illness with the organism also is seen in immunocompromised populations.
I belli is an uncommon human pathogen, linked most commonly to the handling of contaminated cat feces. This organism can cause disease in immunocompetent and immunocompromised hosts, often producing prolonged, profuse, watery diarrhea; anorexia; weight loss; and fever. It has emerged as a significant cause of protracted diarrhea in patients with AIDS in Haiti and, to a lesser extent, in the United States.
Every year, thousands of patients examined at the University of Kentucky, Lexington, are evaluated for diarrheal syndromes. Bacterial cultures remain the first line of diagnosis for acute illnesses, while parasitic infections generally are considered in patients with chronic symptoms and those with appropriate travel histories or other risk factors. Most intestinal parasites can be detected with the combination of a formalin-ethyl acetate concentrate and standard trichrome stain. Wet preparations and trichrome stains do not adequately detect the coccidian organisms, C cayetanensis, C parvum, and I belli. Identification of these organisms requires special staining techniques. The modified acid-fast stain may be used to detect the oocysts of all of these coccidian organisms. The size distribution of the modified acid fast-staining oocysts, together with their overall morphologic features, permits differentiation of these organisms. We used the Kinyoun modified acid-fast stain to perform a point prevalence assessment of these coccidian diseases in patients being evaluated for diarrhea with examination for ova and parasites (O&P) during a 7-month period in central Kentucky.
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