Molecular diagnosis

Conventional PCR

A

A: Agarose gel (2%) analysis of a PCR diagnostic test for detection of Cryptosporidium parvum DNA.  PCR was performed using primers CPBDIAGF and CPBDIAGR.¹

• Lane S: Molecular base pair standard (100-bp ladder).  Black arrows show the size of standard bands.
• Lane 1: C. parvum positive fecal specimen.  The red arrow shows the diagnostic band of 435 bp for zoonotic Cryptosporidium parvum.

Real-Time PCR

A TaqMan-based real-time PCR assay for detection and speciation of Cryptosporidium parvum (bovine genotype) and Cryptosporidium hominis (human genotype) has been developed and validated at CDC.²  The assay combines the detection of two genomic targets: the 18S rRNA gene to achieve a sensitive detection of Cryptosporidium spp. and a gene with unknown function to provide species differentiation.  Each DNA sample is run in two parallel reactions.  The first consists of the highly sensitive detection of the Cryptosporidium 18S rRNA gene and the species-specific detection of C. parvum in a duplex format.  The other reaction detects C. hominis on the species level.

Click here to learn more about TaqMan real-time PCR.

References

1. Johnson DW, Pieniazek NJ, Griffin DW, Misener L, Rose JB. Development of a PCR protocol for sensitive detection of Cryptosporidium oocysts in water samples. Appl Environ Microbiol 1995;61:3849-55.