Interleukin-8, tumor necrosis factor-alpha,and lactoferrin in immunocompetent hosts with experimental and Brazilian children with acquired cryptosporidiosis

To examine the importance of intestinal inflammation in the diagnosis and pathogenesis of human cryptosporidiosis, stools of healthy adult volunteers before and after experimental infection were tested for fecal lactoferrin, interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-alpha). Stool samples of Brazilian children with well-defined Cryptosporidium infection, with or without diarrhea, were also tested for IL-8 and TNF-alpha. Only one of the 14 volunteers challenged with Cryptosporidium had increased fecal lactoferrin. However, of 17 stool specimens from children with only Cryptosporidium infection from a previous study, 12 had mild to moderately elevated lactoferrin despite negative work-up for inflammatory enteritides. One of 10 adult volunteers who developed diarrhea with experimental cryptosporidiosis and three of 11 children with cryptosporidiosis and diarrhea had detectable fecal IL-8. The level of TNF-alpha was increased only in one of 14 volunteers and in none of the children. Although considered relatively non-inflammatory. cryptosporidiosis is often associated with mild inflammation, especially in children in an endemic area.     

Cryptosporidiosis stimulates an inflammatory intestinal response in malnourished Haitian children

The mechanisms by which Cryptosporidium parvum cause persistent diarrhea and increased morbidity and mortality are poorly understood. Three groups of Haitian children <18 months old were studied: case patients, children with diarrhea not due to Cryptosporidium, and healthy control subjects. Compared with both control groups, children with acute cryptosporidiosis were more malnourished (including measures of stunting [P=.03] and general malnutrition [P=.01]), vitamin A deficient (P=.04), and less often breast-fed (P=.04). Markers of a proinflammatory immune response, interleukin (IL)-8 and tumor necrosis factor-alpha receptor I, were significantly elevated in the case population (P=.02 and P<.01, respectively), as was fecal lactoferrin (P=.01) and the T helper (Th)-2 cytokine IL-13 (P=.03). The counterregulatory cytokine IL-10 was exclusively elevated in the case population (P<.01). A Th1 cytokine response to infection was not detected. This triple cohort study demonstrates that malnourished children with acute cryptosporidiosis mount inflammatory, Th-2, and counterregulatory intestinal immune responses.     

Cryptosporidium, enterocytozoon, and cyclospora infections in pediatric and adult patients with diarrhea in Tanzania.

Cryptosporidiosis, microsporidiosis, and cyclosporiasis were studied in four groups of Tanzanian inpatients: adults with AIDS-associated diarrhea, children with chronic diarrhea (of whom 23 of 59 were positive [+] for human immunodeficiency virus [HIV]), children with acute diarrhea (of whom 15 of 55 were HIV+), and HIV control children without diarrhea. Cryptosporidium was identified in specimens from 6/86 adults, 5/59 children with chronic diarrhea (3/5, HIV+), 7/55 children with acute diarrhea (0/7, HIV+), and 0/20 control children. Among children with acute diarrhea, 7/7 with cryptosporidiosis were malnourished, compared with 10/48 without cryptosporidiosis (P < .01). Enterocytozoon was identified in specimens from 3/86 adults, 2/59 children with chronic diarrhea (1 HIV+), 0/55 children with acute diarrhea, and 4/20 control children. All four controls were underweight (P < .01). Cyclospora was identified in specimens from one adult and one child with acute diarrhea (HIV-). Thus, Cryptosporidium was the most frequent and Cyclospora the least frequent pathogen identified. Cryptosporidium and Enterocytozoon were associated with malnutrition. Asymptomatic fecal shedding of Enterocytozoon in otherwise healthy, HIV children has not been described previously.     

Markers of enteric inflammation in enteroaggregative Escherichia coli diarrhea in travelers

As part of a traveler's diarrhea study carried out in Guadalajara, Mexico, and Goa, India, we conducted a case control study to evaluate fecal markers of enteric inflammation in three groups. Forty-five cases of enteroaggregative Escherichia coli (EAEC) diarrhea were compared to 56 controls with enterotoxigenic E. coli (ETEC) diarrhea, and 126 controls with diarrhea without identifiable pathogens. For EAEC cases we found fecal leukocytes, occult blood, and lactoferrin in 13 (28.9%), 14 (31.1%), and 27 (60.0%) patients, respectively; for ETEC controls they were 15 (26.8%), 16 (28.6%), and 15 (26.8%) respectively; and for patients without identifiable pathogens 19 (15.1%), 34 (27.0%) and 27 (21.4%) were seen for the presence of a positive fecal lactoferrin test in EAEC cases was statistically significant compared to both control groups. The study provides evidence that EAEC infection is associated with an intestinal inflammatory response.     

Cryptosporidium Spp., a frequent cause of diarrhea among children at the Korle-Bu Teaching Hospital, Accra, Ghana

This report presents the results of a study conducted at the Child Health Department, Korle-Bu Teaching Hospital, Accra, Ghana, between the months of October 2001 and June 2002. Stool samples from 227 children with diarrhea and 77 children without diarrhea, aged less than 5 years, were tested for Cryptosporidium spp. Prevalence rates were 27.8 and 15.6% in children with and without diarrhea, respectively. Cryptosporidium infection was found to be high in children between the ages of 6 and 24 months. Cryptosporidium spp. was more common in malnourished children, but was not isolated in children under 6 months of age who were exclusively breastfed. Neither the presence of domestic animals, abdominal pain, blood in stool, nausea, vomiting, nor the consumption of untreated water was associated with Cryptosporidium spp. infection. Shigella, Salmonella, and yeast-like organisms were the most frequently identified enteropathogenic bacteria. In summary, this study demonstrates the prevalence of Cryptosporidium spp. among Ghanaian children.     

Markers of inflammation in bacterial diarrhea among travelers, with a focus on enteroaggregative Escherichia coli pathogenicity

The intestinal inflammatory response of traveler's diarrhea acquired in Goa, India, and Guadalajara, Mexico, was studied. Fecal lactoferrin was found in stool samples in which enteroaggregative Escherichia coli (EAEC), enterotoxigenic E. coli, or Salmonella or Shigella species were isolated, with Shigella-positive cases showing the highest level. Samples from cases of Shigella-associated diarrhea had the highest concentrations of fecal cytokines. Travelers to India who had EAEC-associated diarrhea showed elevated levels of interleukin (IL)-8 (median, 341.15 pg/mL) and IL-1beta (median, 749.90 pg/mL). Although 15 travelers to Mexico who had EAEC-associated diarrhea had a median concentration of 0 pg/mL for both IL-8 and IL-1beta, 2 had high levels of IL-8 (1853 and 11,786 pg/mL), and 5 showed elevated levels of IL-1beta (1-1240 pg/mL). Samples from patients in India who had pathogen-negative diarrhea or from patients in Mexico who had asymptomatic EAEC infection were negative for cytokines. Bacterial pathogens causing traveler's diarrhea commonly produce intestinal inflammation, although a subset of patients with EAEC-associated diarrhea fail to develop an inflammatory response.     

Cryptosporidium infection in young children with diarrhea in Rawalpindi, Pakistan.

Fecal excretion of Cryptosporidium parvum oocysts was determined in 625 children less than five years old who presented at the pediatric clinic of a teaching hospital in Rawalpindi, Pakistan. Single stool specimens were collected from 475 children with acute diarrhea and from 150 children without diarrhea. The Cryptosporidium infection rate was significantly higher in children with diarrhea than in children without diarrhea (10.3% versus 3.3%). The C. parvum infection rate was highest in children 19-24 months of age (21.8%). There was no significant difference in the Cryptosporidium infection rate among male and female children of any age group studied. Sociodemographic information, drinking water supply, and contact with domestic animals had no significant role in the acquisition of C. parvum infection in our study population. The data suggest that C. parvum is relatively endemic in young children in the Rawalpindi area and that C. parvum may be an important pathogen associated with diarrhea.     

Genetic susceptibility to enteroaggregative Escherichia coli diarrhea: polymorphism in the interleukin-8 promotor region

Enteroaggregative Escherichia coli (EAEC) infection can be identified in 26% of travelers with diarrhea and is associated with fecal interleukin (IL)-8 production. We hypothesized that single-nucleotide polymorphisms (SNPs) in the IL-8 gene are associated with EAEC-related symptoms. Fecal IL-8 production and IL-8 SNPs at 5 loci were identified in 69 US students who remained in Mexico for 5 weeks; 23 subjects had EAEC-associated diarrhea, 7 were asymptomatic EAEC carriers, 22 had nonspecific diarrhea, and 17 were asymptomatic without an enteropathogen. The chances of having EAEC-associated diarrhea were significantly increased among those with the AA genotype at the -251 position (odds ratio [OR], 208.51; 95% confidence interval [CI], 28.5-1525.36) and among those with AT genotype (OR, 14.3; 95% CI, 1.98-105.74), compared with those with the TT genotype at the -251 position. Among subjects with EAEC-associated diarrhea, the AA genotype at the -251 position produced greater concentrations of fecal IL-8 than those with the AT or TT genotype (P=.0053). In the present study, the AA genotype at the -251 position was associated with the occurrence of EAEC-associated diarrhea and increased levels of fecal IL-8.     

Cryptosporidiosis and microsporidiosis in ugandan children with persistent diarrhea with and without concurrent infection with the human immunodeficiency virus

Cryptosporidium spp. and Enterocytozoon bieneusi are enteric pathogens that have emerged as significant causes of persistent diarrhea (PD) in immunologically compromised individuals particularly in association with HIV/AIDS. We conducted a cross-sectional study on the clinical epidemiology of E. bieneusi and Cryptosporidium in children with PD, with and without HIV/AIDS, attending Uganda's Mulago National Referral Hospital. Two hundred forty-three children aged < 60 months, admitted between November 2002 and May 2003 with PD (> 14 days), were analyzed for HIV status and CD4 lymphocyte counts, and stools were screened for the presence of E. bieneusi and Cryptosporidium by microscopy and positive samples genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Eighty (32.9%) of the children were excreting E. bieneusi, and 76 (31.3%) were excreting Cryptosporidium. Ninety-one of the 243 children had HIV, of who 70 (76.9%) had E. bieneusi, versus 10 (6.6%) of the 152 without (odds ratio = 47.33; 95% CI = 19.88 to 115.97), while 67 (73.6%) had Cryptosporidium, versus 9 (5.9%) without (odds ratio = 44.36; 95% CI = 18.39 to 110.40). Children with counts < 25% CD4 cells were more likely to have either E. bieneusi (odds ratio = 7.42; 95% CI = 3.77 to 14.69) or Cryptosporidium (odds ratio = 6.45; 95% CI = 3.28 to 12.76) than those with higher CD4 percentages. However, only HIV status was independently associated with either Cryptosporidium or E. bieneusi. Among the 243 children with PD, 67 (27.8%) were infected with both enteric pathogens, with HIV being the only independent predictor of coinfection. Finally, some 81% of HIV-infected children with PD excreted one or both organisms, compared with only 10% of children with PD testing negative for HIV. Seventy-four percent of isolates were C. hominis, the anthroponotic species, 17% were C. parvum, the zoonotic species, and 8% were a mixture of the two or others.     

Natural history of enteroaggregative and enterotoxigenic Escherichia coli infection among US travelers to Guadalajara,Mexico

The natural history of enteroaggregative Escherichia coli (EAEC) and enterotoxigenic E. coli (ETEC) infection was studied among 40 US travelers who provided weekly stool samples for 4 weeks after arrival in Mexico. At enrollment, 5 subjects were colonized by EAEC and 3 by ETEC. During the first 2 weeks after enrollment, 12 developed EAEC diarrhea, 7 developed ETEC diarrhea (5 with mixed EAEC/ETEC diarrhea), 13 had EAEC colonization, and 7 had ETEC colonization. During the third and fourth weeks, 4 experienced EAEC diarrhea, 2 experienced ETEC diarrhea (1 with mixed EAEC/ETEC diarrhea), 31 had EAEC colonization, and none had ETEC colonization. Plasmid DNA analysis showed a high degree of heterogeneity among EAEC isolates. Symptomatic EAEC infection occurred early after arrival in Guadalajara, Mexico, and was as common as ETEC infection. Asymptomatic EAEC infection was recurrent.     

Cryptosporidium parvum in children with diarrhea in Mulago Hospital,Kampala, Uganda

A cross-sectional case-control study (ratio = 3:1) was conducted over a 15-month period to determine the prevalence and consequences of cryptosporidiosis in hospitalized diarrheic children (0-5 years old) at Mulago Hospital in Kampala, Uganda. Cryptosporidium parvum was detected and genotyped among 2,446 children of whom 1,779 (72.7%) had diarrhea, and 667 (27.3%) were age- and sex-matched controls. Of the 1,779 children with diarrhea, 532 (29.9%) had persistent (> 14 days) diarrhea and 1,247 (70.1%) had acute diarrhea. Overall, 444 (25.0%) of the 1,779 children with diarrhea had C. parvum, compared with only 57 (8.5%) of the 667 children without diarrhea (chi2 = 80.2, P < or = 0.0001). Within this group of infected children, 72.8% were infected with genotype 1, 18.4% with genotype 2, and 4.1% with a mixture of both genotypes, and 4.1% isolates were either unclassified or C. meleagridis. The prevalence was highest during the rainy months of April to June. Of the 532 children with persistent diarrhea, 166 (31.2%) had C. parvum compared with 278 (22.3%) of the 1,247 children with acute diarrhea (chi2 = 15.8, P < or = 0.0001). There was a significant association between C. parvum and malnutrition including stunting, being underweight, and wasting. Unfavorable outcome (death or failure to resolve within 14 days) occurred in 139 (72.8%) of the 191 children with C. parvum, and in only 65.1% of the 545 without (odds ratio = 1.117, 95% confidence interval = 1.005-1.243, P = 0.05), Of the 191 children with C. parvum, 24 (12.6%) died, compared with 34 (6.2%) of the 545 without C. parvum (P = 0.005). Mortality rates were higher among children with severe dehydration and persistent diarrhea, and in stunted or underweight children infected with C. parvum. Among Ugandan children, cryptosporidiosis, which remains untreatable, is frequently associated with diarrhea and other serious and unfavorable consequences.     

Enteroaggregative Escherichia coli as a cause of traveler's diarrhea: clinical response to ciprofloxacin.

The purpose of this study was to determine the role of enteroaggregative Escherichia coli (EAEC) in the development of traveler's diarrhea and the clinical response of patients with EAEC diarrhea following treatment with ciprofloxacin. Sixty-four travelers with diarrhea and no other recognized enteropathogen were enrolled in treatment studies in Jamaica and Mexico from July 1997 to July 1998. EAEC was isolated from 29 travelers (45.3%). There was a significant reduction in the duration of posttreatment diarrhea in the 16 patients treated with ciprofloxacin, as compared with that in the 13 patients who received placebo (mean of 35.3 versus 55.5 hours; P = .049). There was a nonsignificant reduction in the mean number of unformed stools passed during the 72 hours after enrollment in the ciprofloxacin-treated group (5.6), as compared with that in the placebo group (7.5) (P = .128). This study provides additional evidence that EAEC should be considered as a cause of antibiotic-responsive traveler's diarrhea.     

Cryptosporidiosis: prevalence, genotype analysis, and symptoms associated with infections in children in Kenya

Cryptosporidium parasites are leading causes of enteric disease, especially in children. A prospective survey on the prevalence of cryptosporidiosis in children less than five years of age was undertaken at six microbiology laboratories in Kenya on fecal samples submitted for routine parasite and ova investigations. Analysis of 4,899 samples over a two-year study period showed an overall prevalence of cryptosporidiosis of 4% that was highest between November to February. Investigations on the nature of enteric diseases prompting ova and cyst examination requests showed 66.4% had acute diarrhea, 9% had persistent diarrhea, and 21% had recurrent diarrhea. The main symptoms were abdominal pain (51.1%), vomiting (51.6%), and abdominal swelling (11%). The prevalence of cryptosporidiosis was highest among children 13-24 months of age (5.2%) and least among those 48-60 months of age (2%). No significant differences were observed by sex but vomiting was slightly higher in males than in females (65% males and 52% females; P = 0.07). Cryptosporidiosis was significantly associated with persistent diarrhea (P = 0.0001, odds ratio [OR] = 2.193, 95% confidence interval [CI] = 1.463-3.29), vomiting (P = 0.0273, OR = 1.401, 95% CI = 1.04-1.893), and abdominal swelling (P = 0.0311, OR = 1.56, 95% CI = 1.04-2.34). Genotype analysis based on polymerase chain reaction-restriction fragment length polymorphism of the 18S rRNA gene fragment showed that 87% (153 of 175) of the Cryptosporidium isolates were C. hominis, 9% (15 of 175) were C. parvum, and remaining 4% were C. canis, C. felis, C. meleagridis, and C. muris. The most common protozoa in coinfected patients were Entamoeba histolytica/E. dispar, E. coli, and Giardia intestinalis (6%, 5%, and 2%, respectively). Our results show that Cryptosporidium is among the most common protozoan parasites in children with enteric diseases and that anthroponotic species are the leading cause of human cryptosporidiosis in Kenya, which suggests that human-to-human transmission is the main mode of spread.     

Endemic Cryptosporidium and Giardia lamblia infections in a Thai orphanage

We conducted a point prevalence survey for enteric protozoa in 205 institutionalized orphans 1-61 months of age in Bangkok, Thailand. Cryptosporidium was identified in 17 children (8%), Giardia lamblia in 42 (20%), and 3 children (1%) had both parasites. At the time of diagnosis, diarrheal symptoms were present in a minority of subjects: 36% of children with Cryptosporidium alone, 10% with G. lamblia alone, and in 20% of those with neither parasite. Although chronic nutritional status (height/age) was similar in all groups, acute nutritional status (weight/height) was lower only in children with Cryptosporidium (Z score = -1.39 +/- 0.13) compared with children with G. lamblia (mean Z score +/- SEM = -0.56 +/- 0.26) or neither parasite (Z score = -0.78 +/- 0.13; P = 0.05). Detectable levels of Cryptosporidium-specific IgG antibodies by ELISA were identified in 15 of 16 Thai children with Cryptosporidium and in 17 of 19 Thai children without Cryptosporidium (mean OD +/- SEM = 1.27 +/- 0.18 vs. 1.06 +/- 0.13, respectively), but in only 1 of 18 sera from toddlers in day-care centers in Denver, CO (OD = 0.128 +/- 0.03). Although neither infection with Cryptosporidium nor G. lamblia was consistently associated with acute diarrheal symptoms, Cryptosporidium was more often associated with depressed acute nutritional status than G. lamblia. The high prevalence of specific antibodies to Cryptosporidium in Thai orphans suggests an association between high rates of exposure with asymptomatic excretion of the parasites.     

Enteroaggregative Escherichia coli diarrhea in travelers: response to rifaximin therapy.

BACKGROUND AND AIMS: We have recently shown that enteroaggregative Escherichia coli (EAEC) strains commonly cause travelers' diarrhea. The study was designed to determine whether U.S. travelers with EAEC diarrhea responded to rifaximin therapy. METHODS: In a multicenter placebo-controlled clinical trial of travelers' diarrhea without non-EAEC pathogens we evaluated 2 doses of rifaximin. EAEC was sought in stool samples in enrolled subjects by HEp-2 cell assay. Response to rifaximin (both groups combined) and placebo were evaluated in EAEC-positive and EAEC-negative patient groups. RESULTS: Compared with placebo, rifaximin shortened the postenrollment illness in travelers with EAEC diarrhea (median, 22 vs. 72 hours; P = 0.03). In subjects with EAEC-negative diarrhea, the median duration of post-treatment diarrhea was shorter with rifaximin (33 hours) than with placebo (52 hours), but this difference was not significantly different (P = 0.14). CONCLUSIONS: Improvement of EAEC-mediated diarrhea with antibiotic treatment supports the pathogenicity of this organism in travelers to developing countries. The study provides information on the value of the poorly absorbed drug rifaximin in therapy of travelers' diarrhea.     

Enteroaggregative Escherichia coli virulence markers: positive association with distinct clinical characteristics and segregation into 3 enteropathogenic E. coli serogroups

BACKGROUND: Enteroaggregative Escherichia coli (EAEC) are a heterogeneous category of emerging pathogens associated with acute and persistent diarrhea. METHODS: We performed a case-control study to evaluate the association of EAEC strains and their virulence markers with infantile diarrhea in Brasilia, Brazil. RESULTS: Of the EAEC markers that were tested, only EAEC heat-stable toxin (EAST1), protein involved in colonization (Pic), and the CVD432 sequence showed positive correlation with diarrhea; however, these virulence traits presented associations with distinct clinical characteristics. Although CVD432-positive strains were associated with persistent diarrhea, EAST1-positive strains were statistically correlated with acute diarrhea only in children >6 months of age. Typical EAEC strains were found with equal frequency in case patients and control subjects. O antigens of enteropathogenic E. coli (EPEC) were also sought, and the data showed that the EAEC markers are frequently segregated into 3 EPEC serogroups: O126, O128, and O158. CONCLUSIONS: The presence of EPEC O antigens along with EAEC markers influenced the positive association of E. coli strains with diarrhea. Concerning the detection of the AA phenotype, the CVD432 sequence presented a low positive predictive value, regardless of its high specificity as a marker.     

Enteroaggregative Escherichia coli in Venda, South Africa: distribution of virulence-related genes by multiplex polymerase chain reaction in stool samples of human immunodeficiency virus (HIV)-positive and HIV-negative individuals and primary school children

We used a multiplex polymerase chain reaction (PCR) and a quantitative real-time PCR to determine the distribution of three enteroaggregative Escherichia coli (EAEC) virulence-related genes in stool samples from hospital patients and school children in the Venda region of South Africa. At least one gene was found in 52 (16.5%) samples, 50 (19.6%) from hospitals and 2 (3%) from schools. The AA probe was found in 36 (69%), the aggR gene was found in 41 (79%), and the aap gene was found in 49 (94%) of all positive samples. EAEC was significantly associated with diarrhea and intestinal inflammation and was significantly higher (chi(2) = 5.360, P = 0.021) in human immunodeficiency virus (HIV)-positive persons (29.5%) than in HIV-negative persons (13.7%). The presence of EAEC genes was significantly associated with occult blood (chi(2) = 30.543, P < 0.0001) in the stool samples. This study suggests that the clinical presentation of EAEC infection may be directly related to the bacterial load as well as to the genetic characteristics of the strains involved.     

A newly recognized cause of travelers' diarrhea: enteroadherent Escherichia coli

Adherence to HEp-2 tissue culture cells has been proposed as a virulence characteristic of enteropathogenic Escherichia coli (EPEC). A preliminary study revealed that E. coli that adhered to HEp-2 cells, but did not produce conventional enterotoxins and did not belong to recognized EPEC serogroups, could be isolated from adults from the United States who acquired diarrhea in Mexico. The purpose of this study was to determine the prevalence of these enteroadherent E. coli (EAEC) in 188 travelers with diarrhea and in 92 well travelers. EAEC were found in 14.9% of patients with diarrhea and in 7.6% of well individuals. Compared with well travelers, patients with diarrhea in whom no recognized enteropathogen could be identified had a 30.4% prevalence of EAEC (P less than .0003). These results further support our finding that EAEC are associated with diarrhea in travelers to Mexico and may help to explain the effect of antibiotics in the prevention and therapy for travelers' diarrhea in patients with no recognized bacterial enteropathogens.     

Prevalence of different virulence factors and biofilm production in enteroaggregative Escherichia coli isolates causing diarrhea in children in Ifakara (Tanzania)

This study investigated the prevalence of 19 virulence factors and biofilm production in 86 EAEC isolates causing diarrhea in children less than 5 years of age from Ifakara, Tanzania. Virulence factors were detected by PCR, whereas biofilm production was determined using a microtiter plate assay. No virulence factor, with the exception of the aat gene used to identify EAEC, was detected in 11/86 isolates (12.8%). The most frequently detected virulence factor was the aggR gene in 53 (61.6%) EAEC, followed by antigen 43 in 33.7%, dispersin in 26.7%, yersiniabactin in 22.1%; autrotransporter Sat in 20.9%; Shigella enterotoxin-1 in 16.3%, and heat-stable toxin-1 in 15.1%. Biofilm was produced in 66/86 (76%) isolates. AggR was the most prevalent virulence factor in the biofilm-forming group (65% versus 38%, P = 0.032). These results again show the high heterogeneity of virulence factors among EAEC isolates causing diarrhea in children, and that biofilm may be an important virulence factor, strongly associated with the presence of AggR.     

Identification of 5 types of Cryptosporidium parasites in children in Lima, Peru

Cryptosporidium parvum is usually considered to be the pathogen responsible for human cryptosporidiosis. We genotyped Cryptosporidium in 132 stool specimens from 80 Peruvian children, representing 85 infection episodes, using techniques that differentiate Cryptosporidium species and C. parvum genotypes. Five types of Cryptosporidium were identified: C. parvum human (67), bovine (8), and dog (2) genotypes, C. meleagridis (7), and C. felis (1). Twenty-five (29%) of the 85 infection episodes were associated with diarrhea. There was no significant difference in age, antecedent stunting, percentage with diarrhea, or duration of diarrhea for episodes with human genotype, compared with those of zoonotic Cryptosporidium. Duration of oocyst shedding was longer for human genotype than for zoonotic Cryptosporidium (mean, 13.9 days and 6.4 days, respectively; P=.004). Serum samples from 8 children with C. meleagridis, C. felis, or C. parvum dog genotype were tested for anti-human immunodeficiency virus (HIV) type 1 antibodies; all were found to be negative. Contrary to common belief, novel Cryptosporidium species and C. parvum genotypes can infect HIV-negative children.