Researchers develop tool to detect NDV in poultry
Researchers from the College of Veterinary Science and Medicine (CVSM) of the Central Luzon State University (CLSU) have developed a technology that can provide an alternative method for detecting the Newcastle Disease Virus (NDV).
The method is more affordable, simple yet sensitive and more robust for surveillance and control of NDV.
The technology was generated through the project, “Phylogenetic Characterization and Detection Using Dry Format RT-LAMP of Emergent Newcastle Disease Virus (NDV) in the Philippines,” funded by the Bureau of Agricultural Research in a form of a research grant which CLSU won during the 27th National Research Symposium (NRS) under the applied research category.
According to project leader Clarissa Yvonne Domingo, NDV is a serious, contagious and fatal viral disease that affects species of birds. Currently, it’s a major concern in poultry production, killing thousands of chicken.
The symptoms in chicken generally include gastro- intestinal, respiratory and neurological signs and may vary from subclinical to sudden death with 100 percent mortality.
Mortality is very high in unvaccinated poultry flocks. However, it can still infect and cause death even in vaccinated poultry. Most of infected chickens die from NDV but can also spread the virus since the transmission is both directed contact with infectious body excretions and airborne.
“The key to control and successfully eradicate the NDV disease is to detect it as early as possible and prevent it to spread,” said Domingo.
Due to the confirmed NDV outbreak last year, Domingo and her team formulated a dry format RT-LAMP or the reverse transcription-loopmediated isothermal amplification which is an alternative nucleic acid amplification based (NAB) assay for detecting NDV.
This test assay is rapid, simple, sensitive and very convenient to use by any adapting veterinary poultry practitioner or an animal diagnostician working in a laboratory with simple resources. It can be used for early NDV detection thus, is a powerful and promising tool for monitoring, surveillance and control of the disease.
The genetic sequence of the field virus isolate during the outbreak is the basis for the LAMP primer design thus the assay is very specific.
From the phylogenetic characterization of the field virus, the project found that it was distantly related from the La Sota vaccine virus used in the commercial vaccines. Hence, the genetic sequence of the field virus can be used for developing new vaccine for emergent virulent NDV strain in the Philippines.
RT-LAMP tool is composed of premixes or readymixed substance that are dried and stabilized in a single tube using a cryprotectant to prolong the shelf life at ambient temperature.
The assay has a one-step ribonucleic acid (RNA) extraction process, therefore, the test method is devoid of the usual traditional commercial kit for RNA extrac- tion.
The ground-breaking feature of the modified RTLAMP is the simplicity of its protocol and the low cost of application. It follows a simple procedure by just adding the 11.5 microliter of nuclease-free water into the dry LAMP premix followed by one microliter of the RNA crude extract to reconstitute the dry mix.
Domingo explained that the dry format of the RTLAMP removes the need for storing the tubes at freezing temperature thus, they can now be kept at room temperature. This feature also removes the fear of reagent degradation and assures that the diagnosis of newcastle disease in local poultry farms in endemic areas would be faster thus, making it more convenient.
However, because of its very high sensitivity, the assay must be handled care- fully free from contamination in order to get full efficiency of the dry RT-LAMP amplification.
The technology is intended to benefit more veterinary practitioners, poultry raisers, and poultry health scientists.
Through modifications already made by CLSU, dry format RT-LAMP is considered a novel platform for detecting NDV in the Philippines.