Hemoplasmas Are Endemic and Cause Asymptomatic Infection in the Endangered Darwin's Fox (Lycalopex fulvipes)

Abstract

Mycoplasma haemocanis is prevalent in the endangered Darwin's fox (Lycalopex fulvipes) in its main stronghold, Chiloé Island (Chile). The origin of the infection, its dynamics, its presence in other fox populations and the potential consequences for fox health remain unexplored. For 8 years, hemoplasmal DNA was screened and characterized in blood from 82 foxes in Chiloé and two other fox populations and in 250 free-ranging dogs from Chiloé. The prevalence of M. haemocanis in foxes was constant during the study years, and coinfection with "Candidatus Mycoplasma haematoparvum" was confirmed in 30% of the foxes. Both hemoplasma species were detected in the two mainland fox populations and in Chiloé dogs. M. haemocanis was significantly more prevalent and more genetically diverse in foxes than in dogs. Two of the seven M. haemocanis haplotypes identified were shared between these species. Network analyses did not show genetic structure by species (foxes versus dogs), geographic (island versus mainland populations), or temporal (years of study) factors. The probability of infection with M. haemocanis increased with fox age but was not associated with sex, season, or degree of anthropization of individual fox habitats. Some foxes recaptured years apart were infected with the same haplotype in both events, and no hematological alterations were associated with hemoplasma infection, suggesting tolerance to the infection. Altogether, our results indicate that M. haemocanis is enzootic in the Darwin's fox and that intraspecific transmission is predominant. Nevertheless, such a prevalent pathogen in a threatened species represents a concern that must be considered in conservation actions.IMPORTANCEMycoplasma haemocanis is enzootic in Darwin's foxes. There is a higher M. haemocanis genetic diversity and prevalence in foxes than in sympatric dogs, although haplotypes are shared between the two carnivore species. There is an apparent tolerance of Darwin's foxes to Mycoplasma haemocanis.

Keywords: Canidae; Lycalopex; Mollicutes; South America; risk factors.

FIG 1

Map of the study areas, showing hemoplasma infection status in the surveyed Darwin’s foxes and rural dogs. Dogs from Inio, a small fishing village in the south of Chiloé, are shown pooled in a pie chart.

FIG 2

Maximum-likelihood tree of the 16S rRNA gene (893 bp) of Mycoplasma haemocanis for Darwin’s foxes and domestic dogs. A Mycoplasma pneumoniae sequence was used as an outgroup. Bootstrap values of ≥70 are given at the nodes of the tree. Diamonds mark the nucleotide sequence types (ntST) from our study.

FIG 3

Median joining network of the 16S gene (893 bp) of Mycoplasma haemocanis in rural dogs and Darwin’s foxes. Each circle in the network corresponds to a different nucleotide sequence type (ntST), the sizes of the circles correspond to ntST frequencies, the colors of the circles correspond to the two host species (Darwin’s foxes and rural dogs) (A), two geographic sampling sites (Chiloé Island and Nahuelbuta) (B), and years of sampling (C). The networks in panels B and C were performed with fox samples only.

FIG 4

Prevalence of Mycoplasma haemocanis depending on different intrinsic and extrinsic variables in Darwin’s foxes. (A) Age groups; (B) sex groups; (C) seasons; (D) study years.