Pattern of Cryptosporidium parvum oocyst excretion by experimentally infected dogs

Lloyd, S.; Smith, Jacob W.

doi:10.1016/s0020-7519(97)00041-6

Cited by 12 publications

(8 citation statements)

References 14 publications

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“…In addition to the known positive litters, several other litters/individual dogs had apparently become infected with Cryptosporidium and/or Giardia between litter sampling at 2 months of age and individual sampling at 3 months, both among litters with unknown status and among previously negative litters. The higher Cryptosporidium prevalence among dogs from positive litters at 3 months old may suggest that it takes some time for the puppies to rid themselves of the infection, which is consistent with the findings of Lloyd and Smith (1997) [ 37 ], that some dogs may shed Cryptosporidium oocysts for more than 80 days. They also found that the oocysts shedding was intermittent with several peaks in all the 6 participating dogs, and 5 out 6 dogs shed oocysts for more than 60 days after becoming infected.…”

Section: Discussionsupporting

confidence: 88%

A longitudinal study on the occurrence of Cryptosporidium and Giardia in dogs during their first year of life

2007

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Section: Discussionsupporting

confidence: 88%

A longitudinal study on the occurrence of Cryptosporidium and Giardia in dogs during their first year of life

2007

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“…Without genetic analysis, it is impossible to accurately predict host specificity or infectious potential of a specific isolate of Cryptosporidium. In a study in which 6-wk-old Beagle dogs were fed oocysts of bovine origin, all dogs became infected and shed oocysts in feces (Lloyd and Smith, 1997). In other studies, healthy pups experimentally inoculated with C. parvum (genotype unknown) developed transient diarrhea and shed oocysts (Wilson and Holscher, 1983;Augustin-Bichl et al, 1984;Sisk et al, 1984).…”

Section: Bovine Gtgccagcagccgcggtaattccagctccaatagcgtatattaaagttgttgcmentioning

confidence: 99%

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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“…However, the majority of studies have not used molecular speciation, without which it is impossible to distinguish morphologically similar species from C. parvum . Dogs have been shown to excrete C. parvum size oocysts, typically at a low level over a prolonged period of time (Lloyd and Smith, 1997). Molecular analysis of isolates obtained from dogs has shown that C. canis is the most common species, followed by C. parvum (Santin and Trout, 2007).…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Role of Companion Animals in the Zoonotic Transmission of Cryptosporidiosis

Smith

Chalmers

Elwin

et al. 2009

Zoonoses and Public Health

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Companion animals owned by human patients with cryptosporidiosis (cases) and those animals owned by the wider human population (controls), were studied to determine whether Cryptosporidium was more likely to be excreted by case animals than controls. A total of 280 recently voided faecal samples (114 case animals and 166 control animals) were collected and tested by immunomagnetic separation and immunofluorescent microscopy. A multivariable model was also created to identify pet characteristics, contacts and management factors associated with Cryptosporidium infection in animals, using information collected by a standardized questionnaire. The model was designed to take into account the clustering of samples at the owner level and whether the sampled animal was a case or control.

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Pattern of Cryptosporidium parvum oocyst excretion by experimentally infected dogs

Cited by 12 publications

References 14 publications

A longitudinal study on the occurrence of Cryptosporidium and Giardia in dogs during their first year of life

A longitudinal study on the occurrence of Cryptosporidium and Giardia in dogs during their first year of life

Cryptosporidium canis n. sp. from Domestic Dogs

Investigation of the Role of Companion Animals in the Zoonotic Transmission of Cryptosporidiosis

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