Bovine Viral Diarrhea Virus (BVDV) -UPSC Current Affairs

Description

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Context

US scientists have produced a first ever gene-edited calf that is resistant to a bovine viral diarrhoea virus (BVDV).
It may help reduce reliance on antimicrobials against cattle disease.

What is Bovine Viral Diarrhoea?

Bovine Viral Diarrhea (BVD) is a disease of cattle caused by the Bovine Viral Diarrhea Virus (BVDV). The virus is widespread and most herds are at risk for infection.

Transmission

BVD is transmitted in a number of ways. Either through a congenital infection of the fetus or after birth.
Congenital infections may cause resorption, abortion, stillbirth, or live-birth.
Congenitally infected fetuses that survive in utero infection (i.e., the live-births) may be born as BVDV-infected calves.
The BVDV infection in these calves will persist during the entire life of the calf, and they will shed BVDV continuously in the farm environment.

Symptoms

In adults, clinical signs are highly variable. Signs of acute infection include fever, lethargy, loss of appetite, ocular dishcharge, nasal dischargem oral lesions, diarrhea and decreasing milk production. Chronic infection may lead to signs of mucosal disease.
In calves, the most commonly recognised birth defect is cerebellar hypoplasia. The signs of this are:
- Ataxia/ lack of voluntary coordination of musle movements;
- Tremors
- Wide stance
- Stumbling
- Failure to nurse
- In severe cases the calf may die.
Transient infections include diarrhea, calf pneumonia, decreased milk production, reproductive disorders, increased occurrence of other diseases, and death
The losses from fetal infection include abortions; congenital defects; weak and abnormally small calves; unthrifty, persistently infected (PI) animals; and death among PI animals.