The present research work was carried out to isolate and identify Newcastle disease virus (NDV) by using haemagglutination inhibition (HI) test and HA-HI virus isolation, embryonated eggs (EE) and chicken embryo fibro...The present research work was carried out to isolate and identify Newcastle disease virus (NDV) by using haemagglutination inhibition (HI) test and HA-HI virus isolation, embryonated eggs (EE) and chicken embryo fibroblasts (CEF). A total of 95 clinical (blood, tracheal and cloacal swabs) and post-mortem (brain, lung, colon and spleen) samples were collected from chickens of field outbreaks of suspected Newcastle disease virus (NDV). The HI and HA-HI were employed to detect NDV in tissue homogenates of all the clinical and post-mortem samples as well as laboratory samples (AF and ICF). Among the four different types of post-mortem samples, virus isolation rate was found to be low in body organs. In CEF cell culture system, the rate of virus isolation from all the aforesaid samples was found to be at 100% with the exception of serum samples;while in tracheal and cloacal swabs, it was at 90%;while in serum, it was at 10%, in all clinical cases. The isolation rate of NDV was higher in CEF culture system (66.7%) compared to that of avian embryos (33.3%). Samples were inoculated and the allantoic fluid (AF) of the dead embryos and the infected culture fluid (ICF) of the CEF were harvested at 24 to 96 hours of the post-infection, respectively, which revealed that the virulent strain of NDV is highly prevalent in the region. The prevalence of NDV was established at 1.1%, 2.1% and 4.2% using HA-HI, EE, and CEF methods. Rapid detection and identification of the virus are crucial for the effective control of the disease as conventional diagnostic methods such as virus isolation on embryonated eggs followed by serological identification in haemagglutination-inhibition test are laborious and time-consuming. The speed of the diagnosis can be considerably increased by using methods based on molecular biology, e.g. reverse transcription—polymerase chain reaction. However, the genetic variability of APMV-1 isolates should be considered carefully as the potential cause for false negative results of genetic-based laboratory tests.展开更多
Mycobacterium avium subsp. paratuberculosis causes chronic inflammation of the intestine known as Johne’s disease (JD) in domestic and wild ruminants including primates. MAP has also been associated with inflammatory...Mycobacterium avium subsp. paratuberculosis causes chronic inflammation of the intestine known as Johne’s disease (JD) in domestic and wild ruminants including primates. MAP has also been associated with inflammatory bowel disease (IBD) so called Crohn’s disease (CD) of human beings, which is incurable even after surgery. By virtue of the pasteurization resistant power, high endemicity of the infection in animals continues to be the permanent source of infection to human population. High bio-burden of MAP in wide range of biotic (animal hosts including human beings) and abiotic environment in each and every country where it has been investigated, serves a reminder about the survival abilities of the MAP in diverse range of environmental conditions. Ability of the MAP to evade immune system of the host and the temporal events during infection of the macro-phages, is an area of major concern and research activities as the pattern of distribution are quiet different from those of other pathogenic intracellular organisms. Moreover, the organism can survive over a wide range of environmental conditions such as high and low environmental temperatures, pasteurization, low pH, and high salt concentration etc. This superior survival efficiency from environmental degradation and dormancy within host allows the pathogen to be available for causing disease and pathogenicity in animals and human beings, when conditions are favorable. Perusal of literature reveal that, despite the availability of whole genome sequence of MAP, a very little is known about the replication, persistence and survival mechanisms of this pathogen. Therefore, this review tries to address the survival mechanisms of Mycobacterium avium subspecies paratuberculosis in the different host species and adverse environmental conditions in order to allow designing of more rational diagnostic and control procedures.展开更多
文摘The present research work was carried out to isolate and identify Newcastle disease virus (NDV) by using haemagglutination inhibition (HI) test and HA-HI virus isolation, embryonated eggs (EE) and chicken embryo fibroblasts (CEF). A total of 95 clinical (blood, tracheal and cloacal swabs) and post-mortem (brain, lung, colon and spleen) samples were collected from chickens of field outbreaks of suspected Newcastle disease virus (NDV). The HI and HA-HI were employed to detect NDV in tissue homogenates of all the clinical and post-mortem samples as well as laboratory samples (AF and ICF). Among the four different types of post-mortem samples, virus isolation rate was found to be low in body organs. In CEF cell culture system, the rate of virus isolation from all the aforesaid samples was found to be at 100% with the exception of serum samples;while in tracheal and cloacal swabs, it was at 90%;while in serum, it was at 10%, in all clinical cases. The isolation rate of NDV was higher in CEF culture system (66.7%) compared to that of avian embryos (33.3%). Samples were inoculated and the allantoic fluid (AF) of the dead embryos and the infected culture fluid (ICF) of the CEF were harvested at 24 to 96 hours of the post-infection, respectively, which revealed that the virulent strain of NDV is highly prevalent in the region. The prevalence of NDV was established at 1.1%, 2.1% and 4.2% using HA-HI, EE, and CEF methods. Rapid detection and identification of the virus are crucial for the effective control of the disease as conventional diagnostic methods such as virus isolation on embryonated eggs followed by serological identification in haemagglutination-inhibition test are laborious and time-consuming. The speed of the diagnosis can be considerably increased by using methods based on molecular biology, e.g. reverse transcription—polymerase chain reaction. However, the genetic variability of APMV-1 isolates should be considered carefully as the potential cause for false negative results of genetic-based laboratory tests.
文摘Mycobacterium avium subsp. paratuberculosis causes chronic inflammation of the intestine known as Johne’s disease (JD) in domestic and wild ruminants including primates. MAP has also been associated with inflammatory bowel disease (IBD) so called Crohn’s disease (CD) of human beings, which is incurable even after surgery. By virtue of the pasteurization resistant power, high endemicity of the infection in animals continues to be the permanent source of infection to human population. High bio-burden of MAP in wide range of biotic (animal hosts including human beings) and abiotic environment in each and every country where it has been investigated, serves a reminder about the survival abilities of the MAP in diverse range of environmental conditions. Ability of the MAP to evade immune system of the host and the temporal events during infection of the macro-phages, is an area of major concern and research activities as the pattern of distribution are quiet different from those of other pathogenic intracellular organisms. Moreover, the organism can survive over a wide range of environmental conditions such as high and low environmental temperatures, pasteurization, low pH, and high salt concentration etc. This superior survival efficiency from environmental degradation and dormancy within host allows the pathogen to be available for causing disease and pathogenicity in animals and human beings, when conditions are favorable. Perusal of literature reveal that, despite the availability of whole genome sequence of MAP, a very little is known about the replication, persistence and survival mechanisms of this pathogen. Therefore, this review tries to address the survival mechanisms of Mycobacterium avium subspecies paratuberculosis in the different host species and adverse environmental conditions in order to allow designing of more rational diagnostic and control procedures.
