Abstract:
Restriction fragment length polymorphism analysis of PCR products (PCR-RFLP) and sequencing
of the variable region of the p104 and PIM genes was performed on samples obtained from South
African T. parva parasites originating from cattle on farms with suspected theileriosis and from
buffalo. p104 and PIM PCR-RFLP profiles similar to those of the T. parva Muguga stock, an isolate
that causes ECF in Kenya, were obtained from three of seven cattle samples collected on a farm
near Ladysmith in KwaZulu-Natal Province. Amino acid sequences of the p104 and PIM genes
from two of these samples were almost identical to the T. parva Muguga p104 and PIM sequences.
This result supports findings from a recent p67 study in which p67 alleles similar to those of the T.
parva Muguga stock were identified from the same samples. While these results suggest the
presence of a cattle-derived T. parva parasite, reports of cattle-to-cattle transmission could not be
substantiated and ECF was not diagnosed on this farm. Although extensive diversity of p104 and
PIM gene sequences from South African T. parva isolates was demonstrated, no sequences identical
to known cattle-type p104 and PIM alleles were identified from any of the buffalo T. parva samples
analyzed. ‘Mixed’ PIM alleles containing both cattle- and buffalo-type amino acid motifs were
identified for the first time, and there appeared to be selection of cattle-type and ‘mixed’-type PIM
sequences in the cattle samples examined.
