Parasitic infections in a New York City hospital: trends from 1971 to 1984

Prevalence of gastrointestinal parasites in children from Verón, a rural city of the Dominican Republic

Gastrointestinal infections impose a great and often silent burden of morbidity and mortality on poor populations in developing countries. The Dominican Republic (DR) is a nation on the island of Hispaniola in the Caribbean Sea. Verón is located in La Alta Grácia province in the southeastern corner of the DR. Dominican and Haitian migrant workers come to Verón to work in Punta Cana, a tourist resort area. Few definitive or comprehensive studies of the prevalence of gastrointestinal parasitic infections have been published in the DR. Historically, most of the definitive studies of water-borne or soil-transmitted parasites in the DR were published more than 30 years ago. Presently, there is a high prevalence of gastrointestinal parasitic infections throughout the poorest areas of the DR and Haiti. In this study we report the prevalence of gastrointestinal protozoan and helminth parasites from children recruited from the Clínica Rural de Verón during 2008 through 2011. Each participant was asked to provide a fecal sample which was promptly examined microscopically for protozoan and helminth parasites using the Centers for Disease Control and Prevention (CDC) fecal flotation technique to concentrate and isolate helminth ova and protozoan cysts. Of the 128 fecal samples examined, 127 were positive for one or more parasites. The age of the infected children ranged from 2–15 years; 61 were males and 66 were females. The only uninfected child was a 9 year old female. Percent infection rates were 43.8% for Ascaris lumbricoides, 8.5% for Enterobius vermicularis, 21.1% for Entamoeba histolytica, and 22.7% for Giardia duodenalis. Of the children examined, 7.8% had double infections. Any plan of action to reduce gastrointestinal parasites in children will require a determined effort between international, national, and local health authorities combined with improved education of schools, child care providers, food handlers, and agricultural workers. A special effort must be made to reach out to both documented and undocumented immigrants working or living in the area and to pre-school aged children or those who are not part of the public education system. Lastly, it is important to address the microbial water quality and food preparation, especially during the weaning transition to solid foods and throughout childhood.

Evaluation of the Triage Micro Parasite Panel for detection of Giardia lamblia, Entamoeba histolytica/Entamoeba dispar, and Cryptosporidium parvum in patient stool specimens

A study comparing the Triage Micro Parasite Panel (Biosite Diagnostics, Inc., San Diego, Calif.) to conventional O&P examination (O&P) was performed using patient fecal specimens. Five hundred twenty-three stool samples were compared. Nineteen specimens were found to be positive by Triage, and 29 were found to be positive by O&P. Seven specimens were positive for Giardia lamblia, four were positive for Entamoeba histolytica/E. dispar, and three were positive for Cryptosporidium parvum as determined by both methods. There was one false positive by Triage (C. parvum) and four false negatives by O&P (two G. lamblia, one E. histolytica/E. dispar, and one C. parvum). The Triage test accurately detected all 18 specimens that contained one of the three organisms that it was designed to detect. The Triage test is a rapid, easy-to-use enzyme immunoassay for the detection of G. lamblia, E. histolytica/E. dispar, and C. parvum in fresh or fresh-frozen fecal specimens. These data suggest that the Triage test can be used as a screen for the immediate testing of stool specimens for these three pathogenic parasites. If Triage test results are negative, O&P can be performed if parasitic infections other than G. lamblia, E. histolytica/E. dispar, or C. parvum are suspected.

No association found between Strongyloides infestation and asthma

It has been postulated that infestation with Strongyloides stercoralis is associated with asthma. We conducted a case-control study to determine whether the presence of parasites is associated with asthma. We undertook a retrospective analysis of 15,856 stool specimens received by our Parasitology Laboratory from January 1989 to December 1992. The diagnosis of asthma was secured by a chart review or a review of the computer diagnosis coding system. An association between asthma and Strongyloides was tested by calculating an odds ratio, as well as a Fisher's Exact Test to estimate the strength of the relationship. We also prospectively collected stool specimens for Strongyloides in asthmatics hospitalized for acute exacerbations of asthma from January 1992 to January 1993. Of 60 subjects with evidence of Strongyloides in a stool specimen, 6 were asthmatic. Of 203 stool-negative controls matched for age, sex, and ethnicity, 13 were asthmatic (odds ratio, 1:62; 95% confidence interval, 0.6-4.4; Fisher's Exact two-tailed, p = 0.39). Of 443 subjects admitted for acute exacerbations of asthma, stool specimens were analyzed for the presence of Strongyloides from 161, of which two were parasitized. These data suggest no statistically significant difference in prevalence of asthma among patients with Strongyloides infestation compared to those without parasitic infection. These results do not support the hypothesis that there is an association, either causal or protective, between Strongyloides infestation and asthma.

Disseminated strongyloidiasis with cutaneous manifestations in an immunocompromised host

Recognition of the characteristic cutaneous eruption of disseminated strongyloidiasis can be crucial for early diagnosis and treatment of this potentially fatal infestation. We describe a corticosteroid-dependent elderly man who had a purpuric eruption. Filariform larvae of Strongyloides stercoralis were found in dermal granulomas and also in the sputum.

Malaria in an urban emergency department: epidemiology and diagnostic features of 25 cases

This article presents a retrospective study of 25 patients diagnosed with malaria in an urban emergency department (ED) between June 1986 and June 1989. The mean annual case rate of malaria in this study group was more than three times the national rate. This may be ascribed to the notable ethnic diversity of the population. A history of travel to an area endemic for malaria was eventually elicited from all patients. The most common chief complaint was fever (56%) followed by abdominal pain (12%). Temperatures were elevated in 70% of the patients, with a mean temperature of 102.9 degrees F (39 degrees C). Gender was found to play a role in delaying diagnosis, with women accounting for 83% of a group of patients requiring multiple ED visits before diagnosis. The authors conclude that malaria must be considered when diagnosing patients in ethnically diverse populations. Gender may be associated with a delay in diagnosis. A careful travel history and a peripheral smear are aids in rapid diagnosis.

Prevalence of cryptosporidiosis in patients undergoing endoscopy: evidence for an asymptomatic carrier state

PURPOSE

We sought to determine the presence of the parasite cryptosporidium in the duodenal aspirates of patients undergoing routine upper gastrointestinal endoscopy.

PATIENTS AND METHODS

The study consisted of 169 patients undergoing upper endoscopy or endoscopic retrograde cholangiopancreatography. Immunocompromised patients were not included in the study population. Samples were aspirated from the second portion of the duodenum. Biopsy specimens were also obtained. Three randomly passed stool samples were obtained from 75% of the patients who were found to have cryptosporidium in the duodenum.

RESULTS

Overall, cryptosporidium oocysts were identified in 12.7% of patients. There was no significant difference in the prevalence of the parasite in any subgroup of procedure or symptom complex. Half of those (46.7%) with positive aspirates had demonstrable cryptosporidium in stool samples, although none of the patients had diarrhea. No patient had detectable cryptosporidium in biopsy samples of the duodenum.

CONCLUSION

The findings suggest a surprisingly high asymptomatic carrier rate for cryptosporidium.

Opportunistic Strongyloides stercoralis infection in lymphoma patients. Report of a case and review of the literature

Strongyloides stercoralis is an intestinal parasite that may cause fatal opportunistic infections in immunocompromised patients. Herein is reported a patient who developed fatal disseminated strongyloidiasis 6 weeks after the initiation of chemotherapy for a large cell lymphoma of the small intestine. After reviewing the clinical and epidemiologic features of 16 other cases of disseminated strongyloidiasis in patients with malignant lymphomas, the currently available laboratory methods for the diagnosis of this parasite are outlined. Because uncomplicated infections are treatable, candidates for chemotherapy or immunosuppression with a relevant geographic history should be screened for S. stercoralis prior to the initiation of the treatment.

Effect of Strongyloides ratti on small bowel function in normal and immunosuppressed host rats

Although Strongyloides stercoralis is a common parasite, little is known about its effect on intestinal function. Published clinical studies are difficult to evaluate and compare because of the inability to differentiate the effects of the parasite load from that of various other coexisting features such as bacterial overgrowth, multiparasitism, malnutrition, or tropical sprue. Using a rat model where these problems do not occur, we found that Strongyloides ratti did not inhibit intestinal function in the healthy rat. In fact, in normal rats S. ratti appeared to increase ileal sucrase activity. In contrast, in the methylprednisolone-treated rat, S. ratti produced a decrease in lactase and sucrase activity and an increase in alkaline phosphatase activity. S. ratti had no effect on 3-O-methylglucose uptake or D-xylose absorption in either group. These results suggest that S. ratti has little effect on small bowel function in a healthy rat but can cause minor alterations in intestinal function in an immunosuppressed, methylprednisolone-treated, malnourished host. These results are also consistent with clinical observations seen with S. stercoralis in humans and with another nematode, Ascaris suus, in the pig model.

Human cryptosporidiosis

Cryptosporidium is an enteric coccidial protozoan recognized in humans in 1976. Since its manifestation as an acquired immunodeficiency syndrome (AIDS)-related infection, new diagnostic techniques have improved recognition of Cryptosporidium oocysts, making apparent its true prevalence in human populations. Cryptosporidium represents 5 to 15% of all enteric pathogens in children in warm climate countries. It is responsible for both endemic and epidemic disease. Day-care center spread is well known, and evidence is strong for person-to-person transmission. The spectrum of illness caused by Cryptosporidium is broad, and while self-limited in immunocompetent individuals, gastrointestinal symptoms can be severe. Asymptomatic infection has been described in population surveys and outbreak investigations. Severe dehydration with malabsorption and failure-to-thrive in children from developing countries has been attributed to this organism. Intractable, incurable diarrhea can be fetal in immunosuppressed adults. Cryptosporidiosis in human immunodeficiency virus-infected individuals is declining in frequency in New York City, possibly reflecting changing sexual behaviors and comparatively low infectivity. No effective treatment for Cryptosporidium has been documented, but clinical trials are in progress.

Demonstration and partial characterization of parasite-specific immunoglobulin A responses in human strongyloidiasis

By using an enzyme-linked immunosorbent assay, serum immunoglobulin A (IgA) responses directed against Strongyloides stercoralis larvae antigens were measured in 104 presumably immunocompetent individuals with chronic uncomplicated strongyloidiasis and in 15 immunocompromised patients with S. stercoralis infection. Fifty healthy North American adults and 18 patients with other helminthic parasites served as controls. All 50 healthy controls were negative for antibody responses (mean absorbance +/- standard deviation = 0.0724 +/- 0.040). The mean absorbance of the 18 parasitized controls was 0.230 +/- 0.087; two individuals parasitized by Ascaris lumbricoides showed positive antibody responses. The mean absorbance of the immunocompetent patients with strongyloidiasis was 0.680 +/- 0.364, with 91 subjects (87.5%) having a positive value (greater than 0.300). Of the immunocompromised patients (mean absorbance +/- standard deviation = 0.735 +/- 0.538), 11 (73%) had a positive antibody response test. When the IgA responses of these two groups were compared, they were not significantly different. There was no correlation between the levels of total serum IgA and the concentration of specific IgA in the infected patients. Both IgA and IgG immunoreactive bands were detected on immunoblots of sodium dodecyl sulfate-polyacrylamide gel electrophoresis-separated larval antigen protein blots. Nineteen bands were recognized by IgG, and 13 were recognized by IgA from sera of infected patients. Several bands displayed specific IgG or IgA reactivity. The present work shows that most patients with strongyloidiasis mount specific IgA responses against filariform larval antigens. These responses are, for the most part, directed against antigens that are different from those recognized by IgG. The lack of correlation between the magnitude of the specific serum IgA responses and the clinical aspects of the infection suggests that these antibodies may not play a central role in the regulation of this parasitosis.