Diversity of avipoxviruses in captive-bred Houbara bustard

Abstract

Implementation of conservation breeding programs is a key step to ensuring the sustainability of many endangered species. Infectious diseases can be serious threats for the success of such initiatives especially since knowledge on pathogens affecting those species is usually scarce. Houbara bustard species (Chlamydotis undulata and Chlamydotis macqueenii), whose populations have declined over the last decades, have been captive-bred for conservation purposes for more than 15 years. Avipoxviruses are of the highest concern for these species in captivity. Pox lesions were collected from breeding projects in North Africa, the Middle East and Central Asia for 6 years in order to study the diversity of avipoxviruses responsible for clinical infections in Houbara bustard. Molecular and phylogenetic analyses of 113 and 75 DNA sequences for P4b and fpv140 loci respectively, revealed an unexpected wide diversity of viruses affecting Houbara bustard even at a project scale: 17 genotypes equally distributed between fowlpox virus-like and canarypox virus-like have been identified in the present study. This suggests multiple and repeated introductions of virus and questions host specificity and control strategy of avipoxviruses. We also show that the observed high virus burden and co-evolution of diverse avipoxvirus strains at endemic levels may be responsible for the emergence of novel recombinant strains.

Prevalence and Genetic Diversity of Avipoxvirus in House Sparrows in Spain

“…We confirmed viral infection by molecular analysis in 63% of all lesions tested (from approximately 50% of birds with visual lesions examined). This result fits within the values previously found in studies using tissue samples (52.1% to 82.2%) [10,34,41]. Negative results by molecular testing may be due to superficial sampling techniques; the necessity of using minimally invasive sampling of live birds may have led to some false negative results.…”

“…CNPV-PD1 was the predominant sequence in southern Spain in 2013 (100% in natural and 83% in agricultural areas), but it was less common in 2014 (50% in natural and urban areas), though this variation was not statistically significant. This strain shows 100% identity to an APV from an american flamingo ( Phoenicopterus ruber ruber ) at Lisbon Zoo, Portugal (HQ875129) [a houbara bustard ( Chlamydotis undulata ) in Morocco (LK021660), a great bustard ( Otis tarda ) in Hungary (KC018066) [7,10,31] and shares 70% similarity to FWPV and CNPV. This sequence shows two amino acid insertions and one deletion at the N-terminal sequenced region compared to all other APV strains.…”

“…Three strains have been found that infect house sparrows in Spain, CNPV-PD1 to CNPV-PD3, although CNPV-PD3, highly similar to CNPV-PD2, has been identified only from a museum skin collected from central Spain in 1911 [23]. The genotype CNPV-PD1 has been detected infecting other species in the Iberian Peninsula and North Africa (Lisbon and Morocco) [10,23,31]. Although the subclade B2 consists of isolates from Sturnidae (starlings and mynahs), to date no APV has been detected in Sturnidae in Spain.…”

“…For instance, Canarypox virus (CNPV) was thought to preferentially infect passerines, while Fowlpox virus (FWPV) affected chickens and turkeys. Taxonomy of genus Avipoxvirus was based on this concept until recent studies showed that Accipitriformes , Columbiformes , Otidiformes and Passeriformes , can be infected by a high diversity of strains [7–10]. More in depth knowledge about the genetic diversity of APV strains is necessary because combined mutations and recombination among well characterized APV strains have been proposed as the source of the variability which may provide new strains with different pathogenicity [5].…”

“…More in depth knowledge about the genetic diversity of APV strains is necessary because combined mutations and recombination among well characterized APV strains have been proposed as the source of the variability which may provide new strains with different pathogenicity [5]. Strain diversity in a single host may be very high, for instance, at least 17 genotypes have been described from houbara bustards, including both CNPV and FWPV genotypes [10]. Because of some APV strains may be found in several bird species the introduction of domestic birds may be a threat for wild birds, especially in isolated populations.…”