Surveillance and control of rabies in La Reunion, Mayotte, and Madagascar

Abstract

Mayotte and La Reunion islands are currently free of animal rabies and surveillance is performed by the French Human and Veterinary Public Health Services. However, dog rabies is still enzootic in Madagascar with 4 to 10 confirmed human cases each year. The number of antirabies medical centres in Madagascar is still scarce to provide easy access to the local population for post-exposure rabies prophylaxis. Furthermore, stray dog populations are considerable and attempts to control rabies by mass campaigns of dog vaccination have not received sufficient attention from the national health authorities. To address these challenges, an expanded program to control rabies needs to be initiated by the Malagasy authorities.

Figure 1

PEP and rabies positive animal samples in Madagascar. (A) Geographical origin of patients receiving PEP at the antirabies medical centre (ARMC) of the Institut Pasteur de Madagascar (IPM) in Antananarivo (2006–2011). Green gradient colour represents the number of bite cases that consult at IPM from different districts. Red triangles represent the ARMC located in each administrative region of Madagascar. (B) Geographical distribution of samples received at the National Laboratory Reference for rabies diagnostic. Madagascar, 2006–2011.

Figure 2

Bat species showing serological evidence of the circulation of lyssaviruses in Madagascar: (A) Eidolon dupreanum and (B) Pteropus rufus.Eidolon dupreanum and Pteropus rufus (or Madagascar fruit bats) are species of megabats in the Pteropodidae family and are endemic to Madagascar.

Figure 3

Pattern of consultations at antirabies medical centre (ARMC) – Institut Pasteur de Madagascar (IPM), Antananarivo, 2006–2011. Mean of weekly visit counts at ARMC (IPM) for 5 years. Weekly visit time series plots (number) (blue-curve) and the moving average (red-curve) for weekly visit counts.

Figure 4

Maximum-likelihood phylogenetic tree of 66 partial N gene sequences (Positions 127–629 nucleotides of the rabies virus genome [[30]]) showing phylogenetic relationships of Malagasy isolates with other isolates originating from Africa. The phylogenetic trees was estimated using a maximum-likelihood (ML) method under the general time-reversible (GTR) model of nucleotide substitution, with the rate of each substitution type estimated from the data using PHYML 3.0 [31]. The ML base frequencies were also estimated from the data, as were the proportion of invariable sites (I) and a gamma distribution of rate variation among sites (Γ) with four rate categories. Tree topology was estimated using the best estimates among simultaneous Nearest Neighbour Interchanges and the approach relying on subtree pruning and regrafting. The support of the data for each internal branch of the phylogeny was estimated using non-parametric bootstrap. Bootstrap support of nodes discussed in the text is indicated. The tree is rooted between the Africa 2 and the Cosmopolitan lineages. The generated sequences have been deposited in GenBank under accession numbers KC787050 to KC787074, DQ420623 and U22854.