Goose Parvovirus (GPV) - Molecular diagnosis (PCR)
Goose parvovirus (GPV), also known as Derzsys disease, is a contagious disease of goslings and ducklings of the muscovy species. The disease is present in the main geese producing countries of Europe as well as in the former Soviet Union, Israel, China, Vietnam and Japan.
This disease is due to a virus of the Parvovirus genus, Parvoviridae family. Parvoviruses have a genome of approximately 5,000 nucleotides with single-stranded DNA (ssDNA), so they are included in Group II of the Baltimore Classification. These viruses are constituted by a capsid of icosahedral symmetry and lacking a viral envelope. The parvoviruses have a size of 18 to 26 nm in diameter.
The transmission of GPV occurs mainly through the fecal-oral route through the ingestion of water or food contaminated by faeces from infected animals. The virus can also be found on surfaces and objects that have been in contact with infected feces. Infected birds excrete large amounts of virus in the feces, which results in a rapid spread of the infection through direct and indirect contact. In addition, in carrier breeders the infection can be transmitted vertically, giving rise to eggs that can contain the virus initiating the pathological process in days after hatching. Once in the organism of the infected bird, the virus multiplies in the intestinal wall and, after a viremic phase, the virus reaches several organs, particularly the liver and the heart. Replication in these organs leads to serious changes that frequently lead to death in 2 to 5 days.
The group of birds that presents a higher rate of infection, are birds with an age between 8 and 12 days. However, clinical cases appear only until 30 days of age. The infection by GPV generally presents an incubation period of 8 to 12 days, although this period can be shortened to 4 or 5 days. Clinical manifestations reach maximum intensity around 15 days post infection. The infection of the older geese can occur subclinically and establish a latent infection. This group can act as a carrier of the virus, transmitting it through the eggs, which gives rise to problems of infertility and hatchability, as well as the birth of congenitally infected birds. In some cases, the infection can cause oropharyngeal and lingual diphtheria and pseudomembrane formation. These birds can regurgitate water and food. Other signs include shaking of the head, anorexia and weakness, oculo-nasal secretion, locomotor ataxia, ruffled feathers and growth retardation. In addition, in some cases, birds may have respiratory distress, diarrhea and spots in the cloaca.
The course of the disease depends to a large extent on the age of the infected bird. In goslings less than seven days old, the mortality rate per GPV can be up to 100%. The severity of the disease in neonatal birds depends on the presence of maternal antibodies that can protect them against the disease, but they become asymptomatic carriers and excretors of the virus.
Recommended tests for diagnosis:
The molecular diagnosis by means of PCR (Polymerase Chain Reaction), is the most recommended method at the moment.
Tests carried out in IVAMI:
- Molecular diagnosis (PCR: Polymerase Chain Reaction), to detect DNA from Parvovirus.
Conservation and shipment of the sample:
- Refrigerated (preferred) for less than 2 days.
- Frozen: more than 2 days.
Delivery of results:
- Molecular diagnosis (PCR): 24 to 48 hours.
Cost of the test:
- Molecular diagnosis (PCR): Consult firstname.lastname@example.org.
- Diagnosis and molecular identification (PCR and sequencing): Consult email@example.com.