Cross-Reactivity of Some Cryptosporidium Species with Cryptosporidium parvum Coproantigen in a Commercial ELISA Kit

Abstract

To obtain information about the prevalence of Cryptosporidium parvum in cattle in Oyo State, Nigeria, a commercially available enzyme-linked immunosorbent assay (ELISA) kit made from Cryptosporidium-specific
antibodies raised against antigens of Cryptosporidium parvum was used to screen 406 randomly collected fecal samples from cattle in four White Fulani herds. The overall prevalence was 32.3% (131/406) with 44 % (37/84), 36.5% (35/96) and 26.1% (59/226) prevalence in ages <
6 months, 6 – 12 months and > 12 months respectively. Further analysis of some of the ELISA-positive samples using nested polymerase chain reaction-restriction fragment length polymorphism (PCR– RFLP) and DNA sequencing of the small subunit (18S) rRNA gene identified the isolates as
Cryptosporidium bovis and C. ryanae. The use of molecular tools showed that there is crossreactivity between C. bovis and C. ryanae with the
Cryptosporidium-specific antibodies raised against antigens of Cryptosporidium parvum, thereby eliminating the false alarm about the possible risk of zoonotic transmission in the study area. This work showed that unlike some other livestock diseases where commercially available ELISA kits are often relied on as diagnostic tools, ELISA kits obtained
from Cryptosporidium-specific antibodies are not reliable for assessing risk of zoonosis in epidemiological studies.