Analysis of p67 allelic sequences reveals a subtype of allele type 1 unique to buffalo-derived Theileria parva parasites from southern Africa.

Lubembe D Mukolwe,David O Odongo,Charles Byaruhanga,Louwtjie P Snyman,Kgomotso P Sibeko-Matjila,Gordon Langsley

doi:10.1371/journal.pone.0231434

Lubembe D Mukolwe, David O Odongo + Show 4 more

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https://doi.org/10.1371/journal.pone.0231434

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Abstract

East Coast fever (ECF) and Corridor disease (CD) caused by cattle- and buffalo-derived T. parva respectively are the most economically important tick-borne diseases of cattle in the affected African countries. The p67 gene has been evaluated as a recombinant subunit vaccine against ECF, and for discrimination of T. parva parasites causing ECF and Corridor disease. The p67 allele type 1 was first identified in cattle-derived T. parva parasites from East Africa, where parasites possessing this allele type have been associated with ECF. Subsequent characterization of buffalo-derived T. parva parasites from South Africa where ECF was eradicated, revealed the presence of a similar allele type, raising concerns as to whether or not allele type 1 from parasites from the two regions is identical. A 900 bp central fragment of the gene encoding p67 was PCR amplified from T. parva DNA extracted from blood collected from cattle and buffalo in South Africa, Mozambique, Kenya, Tanzania and Uganda, followed by DNA sequence analysis. Four p67 allele types previously described were identified. A subtype of p67 allele type 1 was identified in parasites from clinical cases of CD and buffalo from southern Africa. Notably, p67 allele type 1 sequences from parasites associated with ECF in East Africa and CD in Kenya were identical. Analysis of two p67 B-cell epitopes (TpM12 and AR22.7) revealed amino acid substitutions in allele type 1 from buffalo-derived T. parva parasites from southern Africa. However, both epitopes were conserved in allele type 1 from cattle- and buffalo-derived T. parva parasites from East Africa. These findings reveal detection of a subtype of p67 allele type 1 associated with T. parva parasites transmissible from buffalo to cattle in southern Africa.

Highlights

Theileriosis is a widespread tick-transmitted protozoal disease of wildlife and domestic animals caused by an apicomplexan parasite of the genus Theileria [reviewed in 1]
Theileria parva positive DNA samples from cattle in East Africa (Kenya, Uganda and Tanzania) and the non-clinical case from South Africa generated single amplicon profiles consisting of the 900 bp and 1000 bp fragments respectively (Table 2 and S1 Fig)
We report identification of a subtype of p67 allele type 1, unique to buffalo-derived T. parva parasites from southern Africa, which can be explored as a marker to differentiate T. parva parasites of p67 allele type 1 responsible for East Coast fever (ECF) and Corridor disease

Summary

Introduction

Theileriosis is a widespread tick-transmitted protozoal disease of wildlife and domestic animals caused by an apicomplexan parasite of the genus Theileria [reviewed in 1]. Theileria parva causes fatal classical East Coast fever (ECF) [3, 4], Corridor disease [5, 6] and January disease [7] occurring in different African countries This parasite is mainly transmitted by a three-host brown ear tick Rhipicephalus appendiculatus, Rhipicephalus zambeziensis and Rhipicephalus duttoni are possible vectors [3, 8, 9]. Corridor disease caused by the buffalo-derived T. parva and only transmissible from buffalo to cattle, is common in South Africa and parts of East Africa [reviewed in 10] It is as fatal as ECF, with an acute onset, and very low schizont and piroplasm parasitosis [10]

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