Duck ring virus (DUCV)

Duck ring virus (DuCV) overview

Duck ring virus (DuCV) belong to the ring, ring virus genera, no capsule is a kind of film, single strand circular DNA virus, has a symmetrical structure of the icosahedron, about 15 to 16 nm in diameter. Due to separate training at present, the DuCV research mainly concentrated in the PCR detection and whole genome sequencing analysis of two aspects.

Clinical symptoms and pathological changes

DuCV infected duck can show the growth and development problems, weight loss, the symptom such as feathers messy, especially back spine feathers malnutrition is more apparent, many feathers scape bleeding. Histopathologic examination mainly for vesicles and around the organization of the vesicles licking inflammatory exudation, internal organs general pathology of duck infectious serositis synergy symptoms of infection, the French's capsule histopathological examination showed that the lymph cell damage, necrosis, tissue cells increased.

Diagnostic methods

Because there is no feasible in vitro multiplication culture DuCV method, it is not completed in the laboratory virus separation identification. Commonly used diagnostic methods including PCR detection and nucleic acid probe hybridization detection. Ordinary PCR and fluorescence quantitative PCR two methods have been used in the diagnosis of DuCV infection, the fluorescent quantitative PCR sensitivity is higher than ordinary PCR.

The prevention and control measures

Due to the spread of DuCV and popular mechanism is not clear, may be horizontal and vertical transmission, therefore suggested that the comprehensive prevention and control measures. Including strengthen management, control and reasonable breeding density and ventilated take a breath, feed add a variety of vitamins, improve the disease resistance and immune function of the duck. At the same time, should strengthen the biological security measures, avoid imported from the epidemic area, for, duck eggs, duck and duck to infection of duck eggs for processing, in order to prevent the spread of the virus.

The latest research

The latest study found, DuCV in multiple sites across the country have a high infection rates, often neglected by clinical symptom is not obvious, thus increases the chances of ducks and other pathogens has multiple infection, aggravating illness and loss. Therefore, the prevention and control of the duck wreath virus, had better comprehensive prevention and control measures, including strengthening the disinfection, regularly on the surrounding environment, site, duck, utensils disinfection, to kill pathogens.

Duck wreath virus pathogens of morphological characteristics

Duck wreath virus (DuCV) is a kind of belong to ring, ring virus is a new virus. This virus has the following characteristics:

• Shape: Duck circovirus has a circular or icosahedral symmetry.
• No posterior capsule: the virus no capsule membrane package.
• Size: the diameter of the virus is about 15 to 16 nm, is one of the smallest duck virus known.
• Structure: the virus ring with single strands of DNA structure.

These characteristics make duck rings on the morphology and other types of viruses, especially its tiny size and simple structure, which may be related to its mode of transmission and infection mechanism.

Clinical symptoms of duck circovirus infection

Ducks infected with duck circovirus may experience some common clinical symptoms as follows:

• Poor growth and development: infected ducks may appear to reduce appetite, weight growth, disorder, plucking feathers (especially the back) and other symptoms.
• Nervous system symptoms: including neurological symptoms seizure, stroke and other abnormal behavior.
• Internal organs lesions: heart bleeding, liver damage may arise such as pathological changes of the internal organs.
• Respiratory symptoms: breathing difficulties may arise, this may be related to lead to decreased immunity after virus infection.
• The change of the skin and feathers: back hair removal is a typical symptoms, in addition, there may be bleeding, feather feather shaft skin histopathological examination may display vesicles and around the organization of the vesicles licking inflammatory exudation.
• These symptoms may lead to duck only a sharp deterioration in health, and even death. Therefore, once found suspected duck circle the symptoms of an infection, should take timely isolation and treatment measures, and enlist the help of a professional veterinarians. At the same time, strengthen management, improve the health level of ducks, and is an important method of prevent duck wreath virus infection.

PCR detection in the diagnosis of duck circle the steps of the virus

PCR (polymerase chain reaction) is a kind of commonly used molecular biology techniques, used to detect and amplify specific DNA sequences. For diagnosis of duck wreath virus, the PCR technology can be used to detect the virus's genetic material, thus confirmed infection. Here are diagnosed by PCR detection duck wreath virus, the general steps:

1. Sample preparation: first of all need ducks infected duck circle from suspected virus samples, the samples usually include liver, pancreas, heart, kidney, spleen, lung, and blood, bursa of fabricius, thymus, hartz gland, droppings and feathers.
2. DNA extraction, processing, the samples will be collected to extract DNA. This step usually involves cell crushing, protein and DNA purification process.
3. PCR amplification: the use of specific primers was carried out on the extracted DNA PCR amplification. These primers was designed according to the known sequence of wreath virus duck, able to combine to the virus DNA specificity. PCR reaction usually include degeneration, annealing and extension three steps, repeated cycle in order to realize the exponential growth of DNA.
4. Product analysis: after the completion of the PCR amplification, through such means as gel electrophoresis analysis of PCR products. If successfully amplified the expected size of DNA fragments, you can think in samples containing duck wreath virus DNA.
5. Results confirmed: in order to ensure the accuracy of the results, usually also need to PCR products for further analysis of the sequence. By comparing the amplification of DNA sequences and the known sequences of duck wreath virus, do exist in the duck wreath virus can confirm sample.

In practice, may also need to optimize the PCR conditions, in order to improve the sensitivity and specificity of detection. In addition, because the duck wreath virus may have different genotypes, sometimes also need to use multiple polymerase chain reaction (PCR) to distinguish between different types of the virus.

Please note that the above steps are common PCR detection process, the specific operation may vary according to the laboratory equipment and reagents. Before the test, Suggestions of consulting a professional veterinary or lab technicians, in order to get detailed guidance and help.