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PCR Test for the Detection of Schmallenberg Virus


Código: ADI491-100. Categorías: , , .

1. Purpose of the test
ADIAVET™ SCHMALLENBERG REAL TIME kit is intended to detect Schmallenberg Virus (SBV) using
real-time Polymerase Chain Reaction (PCR) technology from tissue, brain, whole blood and serum
specimens of bovine, ovine and caprine.
2. Pathogen
The Schmallenberg virus was isolated for the first time in Germany in 2011 by the FLI from blood of
infected cows. The name is based on the geographic origin of the virus (village of the North Rhine-
Westphalia). First phylogenic analyses show that the viral genome presents the most similar sequences
with Shamonda viruses within the Simbu serogroup. These suggest that the novel virus is a Shamondalike
virus within the genus Orthobynyavirus.
Clinical signs of Schmallenberg virus infection in adult ruminants are mainly mild or non-existent but
transient fever, loss of appetite, a reduction in milk yield and diarrhoea have been observed. The main
clinical signs of Schmallenberg virus are congenital malformations (severe arthrogryposis, torticollis,
brachygnathia, hydrocephalus and other severe brain malformations) in newborn animals similar to
those observed in infections by the Akabane virus, the main known virus of the genus.
If infection occurs prior to pregnancy a normal pregnancy is expected to occur. Malformations in
foetuses would be observed when the infection occurs during a vulnerable stage of the pregnancy. In
analogy to Akabane virus, the vulnerable stage of pregnancy may be between days 28 and 36 in sheep
and between days 75 and 110 in cattle.
The viruses of Simbu serogroup are transmitted by insects (Culicoides midges and mosquitoes). It is
likely that Schmallenberg virus is also transmitted by these insects but this has not been confirmed yet.
This way of transmission is reinforced by the clinical signs of Schmallenberg virus infection in adults that
were observed from August onwards, coinciding with the density peak of the putative vectors.
Considering a gestation period of 5 and 9 months for respectively sheep/goats and cows it could be
expected that the majority of the deformed lambs/kids would be born from December to February and
the majority of deformed calves between March and May.
Today, neither vaccine nor treatment exists against the viral infection and no serological test is
available. Viral culture and PCR amplification are the only ways to detect the virus.
Current knowledge suggests that it is unlikely that Schmallenberg virus can cause disease in humans.
3. Description and purpose of the test
This test is based first on the reverse transcription (RT) of RNA into complementary DNA. Then, cDNA is
amplified (PCR) by a DNA polymerase using specific primers. Both enzymatic reactions occur in the
same tube (One-step RT-PCR).
Amplified products are detected in real-time thanks to a specific labelled hydrolysis probe (5’-
exonulease technology).
The ADIAVET™ SCHMALLENBERG REAL TIME kit enables the simultaneous detection of:
– Schmallenberg virus (probe labelled in FAM),
– GAPDH, an internal control of extraction and amplification steps specific from an
endogenous RNA (probe labelled with a fluorochrome read in the same spectra as VIC
and HEX).
ADIAGENE has validated the test using RNA purification kits (Qiagen, Macherey-Nagel). Other
purification kits can be used if they have been validated by the user.

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