Bovine immunodeficiency-like virus: inactivation in milk by pasteurisation

Area of Science:

• Veterinary Virology
• Food Safety
• Bovine Health

Background:

• Bovine immunodeficiency-like virus (BIV) is a lentivirus affecting cattle.
• The presence of BIV in milk raises concerns about its transmission and potential economic impact on the dairy industry.
• Understanding BIV inactivation methods is crucial for ensuring milk safety.

Purpose of the Study:

• To determine if pasteurization inactivates bovine immunodeficiency-like virus (BIV) in milk.
• To assess the risk of BIV transmission through raw or pasteurized milk.
• To evaluate the effectiveness of heat treatment in preventing BIV infection in calves.

Main Methods:

• Bioassay using three groups of calves inoculated with BIV, BIV-seeded milk, or pasteurized BIV-seeded milk.
• Monitoring seroconversion to BIV for 12 months using indirect immunofluorescence assay.
• Detecting BIV proviral DNA in peripheral blood via nested polymerase chain reaction (PCR).
• Post-mortem analysis of tissues (blood, lymph node, spleen) for virus isolation and PCR.

Main Results:

• Calves inoculated with BIV and BIV-seeded milk showed confirmed BIV transmission.
• No evidence of BIV transmission was detected in the group that received pasteurized BIV-seeded milk.
• Seroconversion and proviral DNA presence confirmed infection in non-pasteurized groups.

Conclusions:

• Pasteurization effectively inactivates bovine immunodeficiency-like virus (BIV) in milk.
• Heat treatment of milk is a viable method to prevent BIV transmission to calves.
• BIV in raw milk poses a transmission risk, which is mitigated by pasteurization.