fbpx
Sign up now!
Don't show this again
Download the report!Continue to Site >
or wait 7 secs

Thank you for confirming your subscription!

(And remember, if ever you want to change your email preferences or unsubscribe, just click on the links at the bottom of any email.)

We’re glad you’re enjoying Pig Health Today.
Access is free but you’ll need to register to view more content.
Already registered? Sign In
Tap to download the app
X
Share
X

REPORTS

Collect articles and features into your own report to read later, print or share with others

Create a New Report

Favorites

Read Later

Create a new report

Report title (required) Brief description (optional)
CREATE
X
NEXT
PORK POULTRY
follow us


You must be logged in to edit your profile.

Favorites Read Later My Reports PHT Special Reports
Pig Health Today is equipped with some amazing (and free) tools for organizing and sharing content, as well as creating your own magazines and special reports. To access them, please register today.
Sponsored by Zoetis

Pig Health Today | Sponsored by Zoetis

.

Don’t get complacent with PCV2 protection

Vaccines for porcine circovirus type 2 (PCV2) currently do an adequate job of cross protecting against new genotypes of the virus, but swine veterinarians and producers shouldn’t let their guard down, according to Darin Madson, DVM, PhD, Iowa State University.

PCV2, which is found all over the world and may be present in more than 95% of herds, is the fastest mutating virus that infects swine, Madson said. Its circular genome and its ability to survive under many conditions, including varying temperatures, makes it incredibly resilient.

“There are very few herds that we know of that would be negative for infection,” he told Pig Health Today.

Since 2005 and 2006, when there was a spike in diseases associated with PCV2, the virus has evolved considerably. In the US, PCV2d is now the most common genotype and has been since 2012, followed by 2a, 2b and 2e.

Continuously mutates

Madson said the PCV2 virus was “much different” than most other swine viruses and mutates “on a continuous basis.” The degree of mutation hinges on the PCV2 genotypes circulating in the herd and the vaccines being used.

The other unique thing about PCV2 is that more than one viral genotype may infect the same pig. “It has the ability to recombinate with itself and make new viruses…Different genotypes can infect the same pig and then, all of a sudden, we may have a new, slightly different virus that’s circulating in that particular pig.”

The good news is that despite PCV2’s many mutations in the last dozen years, traditional PCV2 vaccines containing either the 2a genotype have provided adequate cross protection against the PCV2 genotypes circulating in US herds. The development of a new vaccine containing both the 2a and 2b antigens could provide even broader coverage as the virus evolves.

“If you can broaden antigenic diversity, this may increase protection and decrease infection in those animals,” he said.

Targeting vaccines

Madson noted that research data also suggests that the more closely related the virus is the better or stronger the protection.

For example, a vaccine containing either the 2a will be more effective against 2a while still providing some cross protection against 2b, 2d and 2e.  Likewise, a vaccine containing 2b will be better protect against 2b and possibly 2d, which was once known as mutant 2b. The more PCV2 genotypes pigs are exposed to, the higher the level of cross protection.

He expects the PCV2 virus to continue to change.  In addition, researchers have identified what appears to be another species of the virus, PCV3. Unlike the PCV2, which is often transmitted by direct contact, the mode of transmission for PCV3 remains unknown.

The veterinarian noted that PCV3 is similar in structure to PCV2 but “about 200 base pairs larger.”  it’s slightly larger,” Madson said. “But when you look at the genetic makeup…they are only about 30 percent similar,” adding that he doesn’t think PCV2 vaccines would adequately cross protect against PCV3.

“There’s a lot more diagnostic tools that need to be incorporated or developed so that we can really answer those questions,” Madson said.  “Is PCV3 an actual disease or is it just a kind of a virus that’s circulating in the pig population?”

 

 

 

 

 

 

 




Posted on June 28, 2018

tags: ,
RELATED NEWS
  • Johnson: Five steps for porcine circovirus control

    Some breed-to-wean farms that have been vaccinated for porcine circovirus (PCV) have experienced breakdowns in their control of the virus. Clayton Johnson, DVM, outlines his top five steps for managing PCV outbreaks.

  • High prevalence of PCV2 recombinants highlights importance of broad vaccine coverage

    DISCOVERIES, Issue 21: A recent analysis of porcine circovirus type 2 (PCV2) genetic sequences shows that up to 25% of field strains are recombinants of diverse genotypes, highlighting the importance of broad protection when selecting a PCV2 vaccine.

  • Processing fluids provide an option to monitor PCV2 and PCVAD

    Effective PCV2 control relies on vaccination of healthy pigs before they become infected. This goal cannot be accomplished in unstable herds whose sows give birth to viremic pigs.

  • Comparing PCV2 gilt vaccination protocols and progeny status

    Porcine circovirus type 2 is the principal etiological agent of porcine circovirus associated disease (PCVAD), which can cost producers an estimated $3 to $4 per pig.




You must be logged in to edit your profile.

Share It
Influenza A virus in swine (IAV-S) is one of the primary respiratory pathogens challenging swine production systems in the US and around the world. What makes it so transmissible? Watch the interview with Phil Gauger, DVM, PhD, Iowa State University.

Click an icon to share this information with your industry contacts.
Google Translate is provided on this website as a reference tool. However, Poultry Health Today and its sponsor and affiliates do not guarantee in any way the accuracy of the translated content and are not responsible for any event resulting from the use of the translation provided by Google. By choosing a language other than English from the Google Translate menu, the user agrees to withhold all liability and/or damage that may occur to the user by depending on or using the translation by Google.