Culicoides (Diptera: Ceratopogonidae) midges, the vectors of African horse sickness virus – a host/vector contact study in the Niayes area of Senegal

Abstract

BackgroundAfrican horse sickness (AHS) is an equine disease endemic to Senegal. The African horse sickness virus (AHSV) is transmitted to the mammalian hosts by midges of the Culicoides Latreille genus. During the last epizootic outbreak of AHS in Senegal in 2007, 1,169 horses died from this disease entailing an estimated cost of 1.4 million euros. In spite of the serious animal health and economic implications of AHS, very little is known about determinants involved in transmission such as contact between horses and the Culicoides species suspected of being its vectors.MethodsThe monthly variation in host/vector contact was determined in the Niayes area, Senegal, an area which was severely affected by the 2007 outbreak of AHS. A horse-baited trap and two suction light traps (OVI type) were set up at each of five sites for three consecutive nights every month for one year.ResultsOf 254,338 Culicoides midges collected 209,543 (82.4%) were female and 44,795 (17.6%) male. Nineteen of the 41 species collected were new distribution records for Senegal. This increased the number of described Culicoides species found in Senegal to 53. Only 19 species, of the 41 species found in light trap, were collected in the horse-baited trap (23,669 specimens) largely dominated by Culicoides oxystoma (22,300 specimens, i.e. 94.2%) followed by Culicoides imicola (482 specimens, i.e. 2.0%) and Culicoides kingi (446 specimens, i.e. 1.9%).ConclusionsCulicoides oxystoma should be considered as a potential vector of AHSV in the Niayes area of Senegal due to its abundance on horses and its role in the transmission of other Culicoides-borne viruses.

Host preferences and circadian rhythm of Culicoides (Diptera: Ceratopogonidae), vectors of African horse sickness and bluetongue viruses in Senegal

“…This species is abundant in light-traps in the Niayes area (Diarra et al, 2014), a region particularly affected by the previous epizootic outbreak of AHS in 2007; it is also aggressive towards horses (Fall et al, 2015). Furthermore, these studies collected up to 41…”

“…It may be that C. oxystoma and C. kingi also contribute to the transmission of the AHSV in Senegal, and more broadly in West Africa (Fall et al, 2015). Culicoides oxystoma has been reported as a putative vector for BTV in northern India (Prasad et al, 1999), as involved in the transmission of bovine arboviruses such as Akabane virus in Japan (Kurogi et al, 1987;Yanase et al, 2005) and is suspected of transmitting the epizootic haemorrhagic disease virus (EHDV) in Israel (Morag et al, 2012).…”

Immunoinformatics Prediction of Peptide-Based Vaccine Against African Horse Sickness Virus

“…(VP2) is the major protective antigen of (AHSV) that is responsible for the serotype formation. The majority of neutralizing epitopes are located on (VP2) which can be considered as the main target of immune response to the virus [11][12][13]17,18].…”

“…Polyvalent live attenuated vaccine (LAV) that is used to control the disease in Africa was proposed to be unsafe due to the probability of re-assortment between AHSV serotypes. In addition, serotypes 5 and 9 are normally excluded from the (LAV) formulations as serotype 5 is difficult to attenuate and partially crossreacts with serotype 8 and serotype 9 partially cross-reacts with serotype 6 [1,9,11,12,[19][20][21]. A recent Approach applied is the recombinant technology that was used in the development of recombinant modified vaccinia ankara (MVA-VP2) vaccine which is highly protective against (AHSV), but the scale of it is limited to only two serotypes; (AHSV-4) and (AHSV-9) [5,9,10,13,17,18,22].…”

“…Peptides elicit more desirable manipulation of immune response through the use of the B-cell epitopes which mainly induce antibody production and the T-cell epitopes that induce cellular response and cytokine secretion as cytotoxic T-cells. This approaches regarding the molecular basis of antigen recognition and HLA binding motifs to host class I and class II MHC proteins is highly supported by the immunoinformatics which aids in designing epitopes based vaccine motifs that serve as therapeutic candidates for many infectious diseases [5,7,11,12,[23][24][25][26].…”