Peste des petits ruminants in Africa: a review of currently available molecular epidemiological data, 2020

Abstract

Small ruminants (e.g., sheep and goats) contribute considerably to the cash income and nutrition of small farmers in most countries in Africa and Asia. Their husbandry is threatened by the highly infectious transboundary viral disease peste des petits ruminants (PPR) caused by peste-des-petits-ruminants virus (PPRV). Given its social and economic impact, PPR is presently being targeted by international organizations for global eradication by 2030. Since its first description in Côte d'Ivoire in 1942, and particularly over the last 10 years, a large amount of molecular epidemiological data on the virus have been generated in Africa. This review aims to consolidate these data in order to have a clearer picture of the current PPR situation in Africa, which will, in turn, assist authorities in global eradication attempts.

Fig. 1

Distribution of PPRV lineages in Africa. Colours in the circles indicate the viral lineages reported in the country: lineage 1, light green; lineage II, blue, lineage III, dark green; lineage IV, yellow. Adapted with permission from www.d-maps.com

Fig. 2

Phylogenetic tree based on partial sequences of the N protein (217 bp) gene of representative PPRV isolates of lineage IV. The tree was constructed using the maximum-likelihood (ML) method available in MEGA6, employing the Kimura 2-parameter model of nucleotide substitution and 500 bootstrap replications. The model was selected by MEGA6 as the best for the sequences being analysed

Fig. 3

Phylogenetic tree based on partial sequences of the N protein (217 bp) gene of from representative PPRV isolates of lineage III. The tree was constructed using the maximum-likelihood (ML) method available in MEGA6, employing the Kimura 2-parameter model of nucleotide substitution and 500 bootstrap replications. The model was selected by MEGA6 as the best for the sequences being analysed

Fig. 4

Phylogenetic tree based on partial sequences of the N protein (217 bp) gene of representative PPRV isolates of lineage II. The tree was constructed using the maximum-likelihood (ML) method available in MEGA6, employing the Kimura 2-parameter model of nucleotide substitution and 500 bootstrap replications. The model was selected by MEGA6 as the best for the sequences being analysed

Fig. 5

Phylogenetic tree based on partial sequences of the N protein (217 bp) gene of representative PPRV isolates of lineage I. The tree was constructed using the maximum-likelihood (ML) method available in MEGA6, employing the Kimura 2-parameter model of nucleotide substitution and 500 bootstrap replications. The model was selected by MEGA6 as the best for the sequences being analysed

Fig. 6

Phylogenetic tree based on partial sequences of the N protein (217 bp) gene of representative PPRV isolates of lineage II, indicating sequences that are similar to the vaccine strain Nigeria 75/1, indicated by a filled black circle. The tree was constructed using the maximum-likelihood (ML) method available in MEGA6, employing the Kimura 2-parameter model of nucleotide substitution and 500 bootstrap replications. The model was selected by MEGA6 as the best for the sequences being analysed