RESUMEN
Equine infectious anemia virus (EIAV) is a transboundary disease affecting a large number of equines worldwide. In this study, we assessed the transmission risk of EIAV in Rio Grande do Sul, Brazil. Serum samples from 1010 animals from 341 farms were initially analyzed using agar gel immunodiffusion to detect viral antibodies, and no antibody-positive animals were found. A risk assessment stochastic model was applied to generate the expected number of potential infections per month and to estimate the time to new infections. Our results estimated 6.5 months as the interval for new infections in the worst-case scenario. Among the variables evaluated, the number of transported animals and the test sensitivity influenced the model the most. These results were then used to revisit the impact of EIAV control regulations, which triggered a change in the diagnostic testing required for animal movement, in which the validity of a negative test for EIAV was extended from 60 to 180 days. Finally, revisiting the annual average of infected farms before and after the new regulation, the number of infected farms increased pre-implementation, and then, the number of culled animals increased, which should impact future EIAV incidence in this region. Our results demonstrated the importance of constant reviews of disease control programs and provided quantitative-based knowledge for decision-makers in official veterinary services.
Asunto(s)
Anemia Infecciosa Equina , Enfermedades de los Caballos , Virus de la Anemia Infecciosa Equina , Animales , Anticuerpos Antivirales , Brasil/epidemiología , Anemia Infecciosa Equina/epidemiología , Enfermedades de los Caballos/epidemiología , Enfermedades de los Caballos/virología , Caballos , Medición de Riesgo , TransportesRESUMEN
Leptospirosis is a bacterial disease that represents a major problem in animal and public health due to its high prevalence and widespread distribution. This zoonotic disease is most prevalent in tropical environments where conditions favour pathogen survival. The ecological preferences of Leptospira serovars are poorly understood, limiting our knowledge of where and when outbreaks can occur, which may result in misinformed prevention and control plans. While the disease can occur consistently in time and space in tropical regions, research on the ecology of leptospirosis remains limited in subtropical regions. This research gap regarding Leptospira ecology brings public and veterinary health problems, impacting local economies. To fill this gap of knowledge, we suggest to assess geographic and ecological features among Leptospira serovars in a subtropical area of Brazil where leptospirosis is endemic to (a) highlight environmental conditions that facilitate or limit Leptospira spread and survival and (b) reconstruct its geographic distribution. An ecological niche modelling framework was used to characterize and compare Leptospira serovars in both geographic and environmental space. Our results show that despite the geographic overlap exhibited by the different serovars assessed, we found ecological divergence among their occupied ecological niches. Ecological divergences were expressed as ranges of potential distributions and environmental conditions found suitably by serovar, Sejroe being the most asymmetric (<0.15). Most important predictors for the potential distribution of most serovars were soil pH (31.7%) and landscape temperature (24.2%). Identification of environmental preferences will allow epidemiologists to better infer the presence of a serovar based on the environmental characteristics of regions rather than inferences based solely on historical epidemiological records. Including geographic and ecological ranges of serovars also may help to forecast transmission potential of Leptospira in public health and the food animal practice.
Asunto(s)
Leptospira/aislamiento & purificación , Leptospirosis/epidemiología , Animales , Brasil/epidemiología , Ecosistema , Concentración de Iones de Hidrógeno , Estudios Seroepidemiológicos , Serogrupo , Suelo/química , Temperatura , Clima TropicalRESUMEN
Evolution is a multivariate process which, therefore, is expected to leave multiple recognizable signals after episodes of speciation. These signals express in the genome regardless of the mechanism driving speciation, and in a few or in multiple phenotypic traits when divergent selection has been implicated. In lineages that have undergone adaptive radiations (i.e. speciation accompanied by ecological diversification), the phenotypic signals of speciation can be substantially pronounced. In contrast, within non-adaptive radiations (i.e. lineage diversification with minimal ecological diversification linked to allopatric or parapatric species distributions), phenotypic signals of speciation can be minimal. The South American lizard genus Phymaturus is regarded as a candidate non-adaptive radiation given the tendency for non-overlapping distributions among its phenotypically and ecologically similar (i.e. niche conservatism) species. Thus, limited phenotypic divergence has evolved among closely related species. Within the patagonicus clade of the genus, sexual monochromatism is highly conserved, while sexual dichromatism is rare, and mostly negligible when observed. In this paper, we provide the description of a new sexually dimorphic and dichromatic species of this clade (Phymaturus camilae sp. nov.). This species is substantially isolated spatially and phylogenetically separated from P. ceii, P. delheyi and P. zapalensis, the most sexually dichromatic members of the clade. In addition, the new taxon was recently identified as a 'candidate new species' based on molecular (nuclear) phylogenetic evidence.