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Biomedical subjects

R Fayer

Publications and source records attributed to R Fayer.

204 records · Page 12Linked to original sources
PubMedDate not supplied

Mechanical transport and transmission of Cryptosporidium parvum oocysts by wild filth flies.

Over the course of six months wild filth flies were collected from traps left for 7-10 days in a barn with or without a calf shedding Cryptosporidium parvum Genotype 2 oocysts in diarrheic feces. The oocysts of C. parvum transported on the flies' exoskeletons and eluted from their droplets left on visited surfaces were infectious for mice. The mean number of oocysts carried by a fly varied from 4 to 131, and the total oocyst number per collection varied from 56 to approximately 4.56 x 10(3). Fly abundance and intensity of mechanical transmission of infectious C. parvum oocysts were positively correlated, and both increased significantly when an infected calf was in the barn. Molecular data showed that the oocysts shed by infected calves were carried by flies for at least 3 weeks. Filth flies can acquire infectious C. parvum oocysts from unsanitary sites, deposit them on visited surfaces, and therefore may be involved in human or animal cryptosporidiosis.

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PubMedDate not supplied

Effect of hyperimmune bovine colostrum raised against Cryptosporidium parvum on infection of guinea pigs by Cryptosporidium wrairi.

Oocysts shedding was markedly reduced in guinea pigs inoculated intraintestinally with Cryptosporidium wrairi sporozoites that had been incubated with hyperimmune bovine colostrum raised to C. parvum when compared with shedding in guinea pigs inoculated with sporozoites incubated in either non-immune bovine colostrum or buffered saline. However oocyst shedding was apparently not reduced in guinea pigs inoculated by gavage with oocysts of C. wrairi and subsequently treated twice daily per os with hyperimmune bovine colostrum. Similarly, oocyst shedding was apparently not reduced by oral treatment with hyperimmune bovine colostrum when treatment was begun simultaneously with inoculation of C. wrairi oocysts.

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PubMedDate not supplied

Production and preparation of hyperimmune bovine colostrum for passive immunotherapy of cryptosporidiosis.

Pregnant cows were immunized to produce hyperimmune bovine colostrum (HBC) by intramuscular injection or intramammary infusion (TI) followed by 3 successive TI boosters with Cryptosporidium parvum (Cp) oocyst antigen mixed with Freund's (F) or Ribi (R) adjuvant. Control cows received no Cp. Colostrum from all cows was skimmed of butterfat and tested for specific anti-Cp immunoglobulin isotypes by ELISA. The HBC from Cp-F and Cp-R immunized cows had IgG1 titers exceeding 1:400,000 and 1:800,000, respectively. Some HBC from Cp-F immunized cows was freeze-dried to facilitate storage and some were irradiated at 42.5 kGy to kill potentially contaminating pathogens. Freeze-drying, but not irradiation, reduced IgG1 titers by only one dilution. Neither treatment affected Western blot banding patterns.

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