Pfizer Animal Health has written to British vets in order to alert them of a “strong association” between the use of its PregSure bovine viral diarrhoea (BVD) vaccine and cases of bovine neonatal pancytopenia (BNP).
Pfizer Animal Health has written to British vets in order to alert them of a “strong association” between the use of its PregSure bovine viral diarrhoea (BVD) vaccine and cases of bovine neonatal pancytopenia (BNP), commonly known as bleeding calf syndrome.
The company voluntarily suspended sales of PregSure BVD in the UK and other EU states last June after clusters of BNP cases within the EU were linked to the vaccine.
The condition was diagnosed in the UK for the first time in 2009.
Symptoms of BNP include fever and bleeding from the nose, gums, ear-tag holes, rectum and injection sites. However, animals have also been found dead from internal bleeding with no external symptoms. The symptoms are brought about by the destruction of bone marrow, leading to a breakdown of the immune system and blood clotting mechanisms.
In the letter sent to British vets, Pfizer ruminant business unit director Paul FitzPatrick said: “While scientific investigations are still ongoing, Pfizer recently became aware of independently conducted epidemiological surveys which describe a strong association with the use of PregSure BVD and the later development of BNP.”
He also said: “While investigations have looked at a wide range of different causes, research suggests that the consumption of colostrum by the calf may be a key triggering event for the occurrence of BNP. At the moment, the most prevalent hypothesis under discussion is an immunopathological reaction due to alloreactive antibodies, which are transferred to the calves via colostrum.”
“Research has reported that these antibodies may be being stimulated by cell components present in the vaccine as a normal consequence of vaccine production,” he added.
The letter also states that Pfizer has received reports of 445 calves in the UK suspected to be affected by BNP. The company has said that 14 million doses of PregSure VBD have been sold within the EU.