RESUMO
Canine distemper virus (CDV) has recently emerged as an extinction threat for the endangered Amur tiger (Panthera tigris altaica). CDV is vaccine-preventable, and control strategies could require vaccination of domestic dogs and/or wildlife populations. However, vaccination of endangered wildlife remains controversial, which has led to a focus on interventions in domestic dogs, often assumed to be the source of infection. Effective decision making requires an understanding of the true reservoir dynamics, which poses substantial challenges in remote areas with diverse host communities. We carried out serological, demographic, and phylogenetic studies of dog and wildlife populations in the Russian Far East to show that a number of wildlife species are more important than dogs, both in maintaining CDV and as sources of infection for tigers. Critically, therefore, because CDV circulates among multiple wildlife sources, dog vaccination alone would not be effective at protecting tigers. We show, however, that low-coverage vaccination of tigers themselves is feasible and would produce substantive reductions in extinction risks. Vaccination of endangered wildlife provides a valuable component of conservation strategies for endangered species.
Assuntos
Cinomose/prevenção & controle , Espécies em Perigo de Extinção/economia , Tigres/virologia , Vacinação/economia , Vacinas Virais/administração & dosagem , Animais , Animais Selvagens/virologia , Tomada de Decisões Gerenciais , Reservatórios de Doenças/veterinária , Reservatórios de Doenças/virologia , Cinomose/epidemiologia , Cinomose/transmissão , Cinomose/virologia , Vírus da Cinomose Canina/genética , Vírus da Cinomose Canina/imunologia , Cães/sangue , Cães/virologia , Estudos de Viabilidade , Feminino , Masculino , Modelos Econômicos , Filogenia , Estudos Soroepidemiológicos , Sibéria , Tigres/sangue , Vacinação/métodos , Cobertura Vacinal/economia , Cobertura Vacinal/métodos , Cobertura Vacinal/organização & administração , Vacinas Virais/economiaRESUMO
The genomic characteristics of human cytomegalovirus (HCMV) strains sequenced directly from clinical pathology samples were investigated, focusing on variation, multiple-strain infection, recombination, and gene loss. A total of 207 datasets generated in this and previous studies using target enrichment and high-throughput sequencing were analyzed, in the process enabling the determination of genome sequences for 91 strains. Key findings were that (i) it is important to monitor the quality of sequencing libraries in investigating variation; (ii) many recombinant strains have been transmitted during HCMV evolution, and some have apparently survived for thousands of years without further recombination; (iii) mutants with nonfunctional genes (pseudogenes) have been circulating and recombining for long periods and can cause congenital infection and resulting clinical sequelae; and (iv) intrahost variation in single-strain infections is much less than that in multiple-strain infections. Future population-based studies are likely to continue illuminating the evolution, epidemiology, and pathogenesis of HCMV.