RESUMEN
BACKGROUND: Wild Amur tigers are a sparsely populated species, and the conservation of this species is of great concern worldwide, but as an important health risk factor, parasite infection in them is not fully understanding. RESULTS: In this study, sixty-two faecal samples were collected to investigate the frequency and infection intensity of Toxocara cati and Toxascaris leonina in wild Amur tigers. The T. cati and T. leonina eggs were preliminary identified by microscopy, and confirmed by molecular techniques. Infection intensity was determined by the modified McMaster technique. Phylogenetic trees demonstrated that T. cati of wild Amur tiger had a closer relationship with which of other wild felines than that of domestic cats. T. leonina of Amur tiger and other felines clustered into one clade, showing a closer relationship than canines. The average frequency of T. cati was 77.42% (48/62), and the frequency in 2016 (100%) were higher than those in 2013 (P = 0.051, < 0.1; 66.6%) and 2014 (P = 0.079, < 0.1; 72.2%). The infection intensity of T. cati ranged from 316.6 n/g to 1084.1 n/g. For T. leonina, only three samples presented eggs when the saturated sodium chloride floating method was performed, indicating that the frequency is 4.83% (3/62). Unfortunately, the egg number in faecal smears is lower than the detective limitation, so the infection intensity of T. leonina is missed. CONCLUSIONS: This study demonstrated that ascarids are broadly prevalent, and T. cati is a dominant parasite species in the wild Amur tiger population.
Asunto(s)
Tigres/parasitología , Toxascariasis/veterinaria , Toxocariasis/epidemiología , Animales , China/epidemiología , Recuento de Huevos de Parásitos/veterinaria , Filogenia , Toxascariasis/epidemiología , Toxascaris/clasificación , Toxascaris/aislamiento & purificación , Toxocara/clasificación , Toxocara/aislamiento & purificaciónRESUMEN
BACKGROUND: As the natural hosts of avian influenza viruses (AIVs), aquatic and migratory birds provide a gene pool for genetic transfer among species and across species, forming transient "genome constellations." This work describes the phylogenetic dynamics of H1NX based on the complete molecular characterization of eight genes of viruses that were collected from 2014 to 2015 in Anhui Province, China. METHODS: Hemagglutination and hemagglutination inhibition tests were used to determine the hemagglutination (HA) activity of the HA subtypes. The entire genomes of the viruses were sequenced on an ABI PRISM 3500xl DNA Analyzer. The sequences were genetically analysed to study their genetic evolution using DNASTAR and MEGA 6. The pathogenic effects of the viruses were evaluated using mouse infection models. RESULTS: Seven strains of the H1 subtype avian influenza virus were isolated. Phylogenetic analysis indicated natural recombination of the H1 influenza viruses between the Eurasian lineage and the North American lineage. Some genes had high sequence identity with A/bean goose/Korea/220/2011(H9N2), which is a typical case involving viral reassortment between the Eurasian lineage and the North American lineage. The results of infection experiments in mice showed that the viruses could acquire the ability to multiply in mouse respiratory organs without adaptation. CONCLUSIONS: These findings suggest that continued surveillance of wild birds, particularly migratory birds, is important to provide early warning of possible H1 influenza epidemics and to understand the ecology of the virus.
Asunto(s)
Aves , Epidemias/veterinaria , Virus de la Influenza A/clasificación , Virus de la Influenza A/fisiología , Gripe Aviar/epidemiología , Animales , China/epidemiología , Virus de la Influenza A/genética , Gripe Aviar/virología , Filogenia , Análisis de Secuencia de ARN/veterinariaRESUMEN
Although widespread vaccination against canine distemper virus (CDV) has been conducted for many decades, several canine distemper outbreaks in vaccinated animals have been reported frequently. In order to detect and differentiate the wild-type and vaccine strains of the CDV from the vaccinated animals, a novel reverse transcription loop-mediated isothermal amplification (RT-LAMP) method was developed. A set of four primers-two internal and two external-were designed to target the H gene for the specific detection of wild-type CDV variants. The CDV-H RT-LAMP assay rapidly amplified the target gene, within 60 min, using a water bath held at a constant temperature of 65°C. The assay was 100-fold more sensitive than conventional RT-PCR, with a detection limit of 10(-1)TCID50ml(-1). The system showed a preference for wild-type CDV, and exhibited less sensitivity to canine parvovirus, canine adenovirus type 1 and type 2, canine coronavirus, and canine parainfluenza virus. The assay was validated using 102 clinical samples obtained from vaccinated dog farms, and the results were comparable to a multiplex nested RT-PCR assay. The specific CDV-H RT-LAMP assay provides a simple, rapid, and sensitive tool for the detection of canines infected with wild-type CDV from canines vaccinated with attenuated vaccine.
Asunto(s)
Virus del Moquillo Canino/genética , Moquillo/virología , Técnicas de Amplificación de Ácido Nucleico/veterinaria , Vacunas Virales/genética , Animales , Moquillo/diagnóstico , Moquillo/prevención & control , Virus del Moquillo Canino/inmunología , Perros/virología , Reacción en Cadena de la Polimerasa Multiplex/veterinaria , Técnicas de Amplificación de Ácido Nucleico/métodos , Parvovirus Canino/genética , Sensibilidad y Especificidad , Vacunas Virales/uso terapéuticoRESUMEN
Two hundred thirty specimens of wild birds were collected from some areas in Heilongjiang Province during the period of 2003-2004, including two batches of specimens collected randomly from a same flock of mallards in Zhalong Natural Reserve in August and December, 2004, respectively. Primary virus isolation and identification for avian influenza virus (AIV) and Newcastle disease virus (NDV) were performed. The results showed that only two specimens of young mallards collected from Zhalong Natural Reserve in August, 2004 were positive to AIV (isolation rate 0.9%), and one strain (D57) of these two virus isolates was identified to be H9 subtype by hemagglutination inhibition test. Meanwhile, the two batches of blood serum samples of mallards from Zhalong were also examined for antibodies against AIV and NDV. Among 38 blood serum samples collected in August, antibodies against the hemagglutinin of H1, H3, H5, H6 and H9 subtypes of AIV were found in 1, 0, 2, 0 and 8 samples, respectively; and 11 samples were found with antibody against NDV. Whereas the NDV isolation in both two batches of specimens of mallard was negative, all of the 32 blood serum samples collected in December were negative for antibodies against AIV and NDV.