Size of Cryptosporidium oocysts excreted by symptomatic children of Santiago, Chile

Mercado, Rubén; Santander, Federico

doi:10.1590/s0036-46651995000500016

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…1985). Oocysts of a C. parvum human source were 3.8-6.0 by 3.0-5.3 pLm with a mean size of 5.0 by 4.5 pm (Mercado and Santander, 1995). Furthermore, the morphometric feature, the mean shape index, also overlapped between species (1.04 for AF09489, AF093490, AF112575, AF112576, AF115377, AF221528, AF221529, AF221533, AF221535, AF221538, AF247535, and AF247536.) ..........................T .. ......................................................................................... Human HumanP............................................................................................................. ................................T .......... ......................................................T. ......................…”

Section: Remarksmentioning

confidence: 95%

Cryptosporidium canis n. sp. from Domestic Dogs

Fayer¹,

Trout²,

Xiao³

et al. 2001

The Journal of Parasitology

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Oocysts of Cryptosporidium, from the feces of a naturally infected dog and from an HIV-infected human, were identified as the previously reported canine genotype of Cryptosporidium parvum, hereafter referred to as Cryptosporidium canis n. sp. Also among the oocysts from the dog, a trace amount of C. parvum bovine genotype was detected. Cryptosporidium canis oocysts from both the dog and human were infectious for calves. Oocysts excreted by calf 1 (dog source) were approximately 90% C. canis and 10% C. parvum, whereas those excreted by calf 3 (human source) were 100% C. canis. Oocysts from calf 1 infected calf 2 resulting in excretion by calf 2 of oocysts -90% C. parvum and 10% C. canis. Oocysts of C. canis were not infectious for BALB/c neonatal mice or immunosuppressed C57 juvenile mice, although all control mice became infected with the C. parvum Beltsville isolate. Oocysts of C. canis from calf 1 and the human were structurally indistinguishable from oocysts of the C. parvum Beltsville isolate (bovine). However, C. canis oocysts differed markedly at the molecular level from all known species of Cryptosporidium based on sequence data for the 18S rDNA and the HSP 70 gene. The differences in genetics and host specificity clearly differentiate C. canis as a new species. The present study was undertaken to examine oocysts from a dog and an HIV-infected human that matched a previously described genotype of C. parvum associated with dogs and to determine if these oocysts differed enough from known species of Cryptosporidium to be considered a new species. Differences to be examined would include oocyst morphology, host specificity, and gene sequencing. MATERIALS AND METHODS Source of oocystsThe oocysts obtained from the feces of a 25-kg, 16-mo-old, female, mixed-breed dog purchased from a licensed animal dealer were used to determine molecular characteristics as well as potential for transmission to mammalian hosts. Initially, feces from this dog were found negative for Cryptosporidium. One day after receiving the last of 3 intramuscular injections of methyl prednisolone (200, 400, and 200 mg over 3 wk), the dog excreted Cryptosporidium oocysts for only 2 days. Oocysts from a calf (calf 1) experimentally infected with the oocysts from this dog were examined for morphometric, molecular, and transmission characteristics. Additional oocysts from the feces of an adult male citizen of Peru with HIV infection were shipped to the CDC, where a portion were examined for molecular characteristics and the remainder were shipped to the U.S. Department of Agriculture (USDA), where they were measured and tested for animal infectivity. Oocyst preparationOocysts, initially from the dog and the human, and those later obtained from mice and calves, as well as the bovine C. parvum Beltsville isolate, were cleaned of large fecal debris by washing through a graded series of sieves down to a pore size of 45 p~m. Smaller debris was removed by density gradient centrifugation over cesium chloride as previously described (Kilani an...

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Section: Remarksmentioning

confidence: 95%

Cryptosporidium canis n. sp. from Domestic Dogs

Fayer¹,

Trout²,

Xiao³

et al. 2001

The Journal of Parasitology

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“…Three Cryptosporidium oocysts (arrows) with typical sizes ≈5 μm in diameter are visible. Measurements were performed in a calibrated microscope as described by Mercado and Santander ( 11 ). …”

Section: The Studymentioning

confidence: 99%

Cryptosporidium hominisInfection of the Human Respiratory Tract

Mercado

Buck

Manque

et al. 2007

Emerg. Infect. Dis.

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“…Cryptosporidium is a 5-to 10-m round protozoal parasite that affects the digestive epithelium of a variety of animal species. More than 20 species of Cryptosporidium have been identified with questionable host specificity (8,17). Recently, questions regarding identification of the organism to species level have been brought to the forefront for five reasons, as follows.…”

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confidence: 99%

Molecular Analysis of the 18S rRNA Gene of Cryptosporidium serpentis in a Wild-Caught Corn Snake ( Elaphe guttata guttata ) and a Five-Species Restriction Fragment Length Polymorphism- Based Assay That Can Additionally Discern C. parvum from C. wrairi

Kimbell

Miller

Chavez

et al. 1999

Appl Environ Microbiol

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An adult wild-caught corn snake (Elaphe guttata guttata) was presented for humane euthanasia and necropsy because of severe cryptosporidiosis. The animal was lethargic and >5% dehydrated but in good flesh. Gastric lavage was performed prior to euthanasia. Histopathologic findings included gastric mucosal hypertrophy and a hemorrhagic erosive gastritis. Numerous 5- to 7-μm-diameter round extracellular organisms were associated with the mucosal hypertrophy. A PCR, acid-fast stains, Giemsa stains, and an enzyme immunoassay were all positive for Cryptosporidiumspp. PCR and restriction fragment length polymorphism (RFLP) analysis on gastric lavage and gastric mucosal specimens, and subsequent sequencing of the 18S rRNA gene, enabled a distinct molecular characterization of the infecting organism as Cryptosporidium serpentis. Until recently, studies on snakeCryptosporidium have relied on host specificity and gross and histopathologic observations to identify the infecting species. A multiple alignment of our sequence against recently published sequences of the 18S rRNA gene of C. serpentis (GenBank accession no.AF093499 , AF093500 , and AF093501 [L. Xiao et al., unpublished data, 1998]) revealed 100% homology with the C. serpentis(Snake) sequence (AF093499 ) previously described by Xiao et al. An RFLP method to differentiate the five presently sequenced strains of Cryptosporidium at this locus was developed. This assay, which uses SpeI andSspI, complements a previously reported assay by additionally distinguishing the bovine strain ofCryptosporidium from Cryptosporidium wrairi.

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Size of Cryptosporidium oocysts excreted by symptomatic children of Santiago, Chile

Cited by 4 publications

References 6 publications

Cryptosporidium canis n. sp. from Domestic Dogs

Cryptosporidium canis n. sp. from Domestic Dogs

Cryptosporidium hominisInfection of the Human Respiratory Tract

Molecular Analysis of the 18S rRNA Gene of Cryptosporidium serpentis in a Wild-Caught Corn Snake ( Elaphe guttata guttata ) and a Five-Species Restriction Fragment Length Polymorphism- Based Assay That Can Additionally Discern C. parvum from C. wrairi

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