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The Pros and Cons of Using Autogenous Hog Vaccines

Article-The Pros and Cons of Using Autogenous Hog Vaccines

Autogenous vaccines are an important herd health tool. But, at times, they have been touted as a panacea without any basis in fact.Autogenous vaccines are an important herd health tool. They fill a void when new disease agents emerge for which there are no vaccines, or when antigenic variation occurs that is outside the spectrum of protection afforded by commercially available vaccines.They have shown

Autogenous vaccines are an important herd health tool. But, at times, they have been touted as a panacea without any basis in fact.

Autogenous vaccines are an important herd health tool. They fill a void when new disease agents emerge for which there are no vaccines, or when antigenic variation occurs that is outside the spectrum of protection afforded by commercially available vaccines.

They have shown tremendous value in filling these gaps. They have also helped where intensive diagnostic and molecular work-up of isolates have shown there is a need for a different antigen.

However, at other times, autogenous vaccines have been touted as a panacea or "miracle cure" without any basis in fact.

Historical Importance Historically, autogenous vaccines have been important for preventing several hog diseases.

The first widespread use of autogenous vaccines was for colibacillosis (Escherichia coli) in nursing pigs in the 1970s. This was a oral vaccine to prevent baby pig scours. Autogenous vaccines were developed from the gut contents of piglets with diarrhea. Those contents were cultured in milk and fed to pregnant sows a month before farrowing.

With the introduction in the 1980s of highly effective, commercial, killed E. coli bacterins, the use of the oral E. coli milk vaccine dramatically decreased.

Autogenous approaches have been used for common viruses. Prevention of transmissible gastroenteritis (TGE) virus is accomplished using the intestinal tract of TGE-infected piglets as the autogenous vaccine source. The vaccine is fed to pregnant sows at least two weeks before farrowing.

Commercial TGE vaccines had rather poor protection.

Immunity in gilts to parvovirus, an important reproductive disease, is achieved through exposure to fecal material from sows prior to breeding. Although commercial parvovirus vaccines were developed, this fecal, autogenous approach is important.

In all these cases, the animals are "infected" with the autogenous agent. They develop "mucosal" immunity in the gut to transfer to the reproductive tract for parvovirus, and to the mammary gland for E. coli and to the nursing piglet for TGE. Oral autogenous vaccines are highly effective for diseases that infect the intestinal tract.

The next wave of autogenous vaccines in the late `70s was for atrophic rhinitis (AR). These were killed bacterins made from Bordetella bronchiseptica cultured from the nasal passages of nursery pigs. Aluminum hydroxide served as an adjuvant.

In our practice, we had 50-60 different lots of autogenous AR vaccines, customized for each hog operation. These vaccines were injected intramuscularly or subcutaneously. They were not particularly effective.

However, when we added toxin-producing Pasteurella multocida, the effectiveness of many of these autogenous vaccines improved.

Commercial vaccines developed for Bordetella bronchiseptica, Pasteurella multocida and Pasteurella multicida toxoids were fairly effective and replaced many autogenous vaccines.

During the 1970s and early 1980s, these autogenous E. coli and AR vaccines were produced by the local swine practitioner. Soon several small companies began making autogenous hog vaccines using cultures from source farms. This became a thriving industry.

Although the number of companies making autogenous vaccines has decreased, the volume of autogenous vaccines produced has continued to grow.

Autogenous vaccines are now being manufactured for protection against every conceivable hog respiratory, enteric and reproductive virus and bacteria.

Vaccine Production Autogenous vaccines are produced using bacterial and/or viral cultures from the farm of origin. Some may be obtained from pigs or tissue directly submitted to the autogenous vaccine company, from cultures obtained by the herd veterinarian directly or from cultures isolated by a diagnostic laboratory. Almost all autogenous vaccines produced are "killed" products.

Because these vaccines are killed or inactivated, a primary vaccination followed by a booster vaccination in two to three weeks are required to obtain an immune response. These autogenous vaccines are almost all given by injection using adjuvants.

Adjuvants are critical for the development of an immune response that will last over time (duration). Many autogenous vaccines use aluminum hydroxide as an adjuvant. This is a marginal adjuvant and requires frequent revaccination (at least every four to six months) to sustain an immune response.

Recent Autogenous Vaccines Developed More recently, autogenous vaccines have been important to control porcine reproductive and respiratory syndrome (PRRS) and swine influenza virus (SIV).

With PRRS and SIV, their greatest value has been when extensive diagnostic and molecular techniques were used to differentiate the field strains from those organisms in commercial vaccines. These intricate molecular characterizations require the use of a diagnostic laboratory with molecular biology capacity, a prerequisite beyond the scope of most autogenous companies.

Careful monitoring of the genetics of these viruses by veterinary diagnostic laboratories working with researchers is important because both PRRS and SIV viruses mutate easily. The rapid "antigenic shifts" that occur with the different types of SIV may result in new, highly infectious viruses with no commercial vaccines.

A commercial vaccine company can request rapid development of a vaccine from the U.S. Department of Agriculture.

But autogenous vaccines can be produced more quickly, providing an important niche.

The PRRS Problem The use of autogenous vaccines with the PRRS virus is more troublesome. Although the virus mutates rapidly, the genetic changes that are important for immunity and the severity of disease are not well characterized, as they are with SIV.

Several quick genetic methods have been developed to identify viruses that are different. However, they do not predict disease or immunity.

Another unique problem with PRRS vaccines is a patented process for producing the vaccine. The common method of growing PRRS virus in the laboratory has been patented by a commercial company. This has resulted in some autogenous companies being sued for patent infringement. Some companies have reached licensing agreements to produce PRRS virus vaccines, but they will cost more.

Autogenous vaccines are important for emerging diseases, such as circoviruses, for which there are no commercial vaccines.

Autogenous Vaccine Failures Efficacy standards must be met by commercial hog vaccines but not by autogenous products because that would defeat the purpose of autogenous vaccines. They are always an "experimental vaccine."

Often, their success against a disease in the field has resulted in the development of a commercial vaccine.

Likewise, the lack of commercial vaccines being developed reflects their failure.

A case in point are Streptococcus suis vaccines. Strep has more than 30 antigenic types and the protective antigen is not known. Many of the strep problems I encounter in herd health consultations are "untypable" streps.

Therefore, until the protective antigen of strep is known, there will be no broadly effective autogenous vaccines.

Another example of a failed autogenous vaccine is encephalomyocarditis virus (EMC). This virus was first associated with "mystery swine disease," which later turned out to be PRRS virus. In this case, although EMC can be a problem in isolated farms, there was a stampede to make autogenous EMC vaccines before the real problem, PRRS virus, was identified.

Economic Greed A major consideration driving the use of autogenous vaccines is cost. Everyone wants to be more profitable. The decision often boils down to whether the risk of lost production from the disease is greater than the loss of production from vaccination.

Beware of statements that the autogenous vaccine is "just like" company X's, but 10/dose cheaper. A producer in my practice used a bargain Mycoplasmal pneumonia autogenous vaccine. Pigs in the unit developed a recurrent cough and had extensive mycoplasma lesions on slaughter check. In the end, his cost "savings" turned out to be a real loss to this producer.

I strongly support prudent use of autogenous vaccines. At the veterinary clinics where I have worked, we produced many autogenous E.coli and AR vaccines before commercial products became available. Our client herds were cultured routinely and slaughter checks were performed to assess the efficacy of the vaccination program.

One of my biggest complaints is against salespeople who have actively solicited my clients to produce an autogenous vaccine by promising that it would cure their "problems." In most all cases, these units had multiple management problems. That is why adequate diagnostic work-up is essential. Vaccines are only a part of a comprehensive herd health program.

Combination Vaccines Multiple antigen, autogenous products seldom provide good protection. Certain antigens require different types of adjuvants.

Therefore, the use of several antigens in combination can be antagonistic. That is why some vaccines must be given separately. In my experience, this has been a particular problem with Mycoplasmal pneumonia combination vaccines that offer little protection.

Adjuvant Limitations One of the major developments in the vaccine industry in the last 10 years is new adjuvants. The new adjuvants make previously "poor" vaccine antigens for diseases, like mycoplasma, highly effective. Most of these adjuvants are proprietary, available only in commercial vaccines. They require extensive testing to ensure they do not cause side effects such as adverse reactions or abscess.

The proprietary nature and the cost of testing limits the availability of these adjuvants for autogenous vaccines. The result is the use of less efficacious adjuvant formulations in autogenous vaccines.

Recommendations for Autogenous Use First, the use of any vaccine should be science-based. A diagnostic work-up should be performed. The organism and a production problem (reproductive, performance, etc.) should be identified.

Diagnosing the presence of an organism, without any evidence of disease or production abnormalities, doesn't automatically mean we need to control or prevent that organism with a vaccine.

Second, if no commercial vaccine is available and your veterinarian feels an autogenous vaccine is the right approach, contact autogenous manufacturers for cost and minimum order requirements.

Also, check with companies that produce commercial, USDA-approved swine biologicals. They are most likely to have adopted many of the quality control/quality assurance standards from commercial vaccine production and applied them to autogenous production.

Third, if a commercial product is available and hasn't performed to expectations, contact the company. If your veterinarian feels there is no remedy using the commercial vaccine, an autogenous vaccine may be the solution. Again, the organism needs to be re-isolated and extensive diagnostic laboratory evaluation (including genetic analysis) performed to determine that the organism is different from commercial vaccine antigens.

Fourth, if a new commercial product becomes available for the disease agent that the autogenous vaccine was developed against, run a vaccine trial comparing the autogenous to the new product.

Based on the new adjuvants and vaccine technologies, the commercial vaccine will prove to be superior to the autogenous vaccine most of the time.

Finally, don't let the cost of the vaccine be the major factor in selecting an autogenous vaccine over a commercial vaccine. If a complete economic evaluation is not done for the vaccine, looking at performance, morbidity and mortality, the true savings or loss will not be known. Always let science and the economic bottom line guide your decisions - not your emotions or someone else's persuasive skills.

Preventive Herd Health Preventive herd health begins by working with your veterinarian. He or she is trained to evaluate your enterprise and make recommendations to keep productivity high and your operation profitable.

A preventive herd health program is a three-step process: monitoring, biosecurity and vaccination. It's like a three-legged stool. All three legs are required to achieve success.

Monitoring is the first leg. It requires regular visits, walk-throughs by your veterinarian. Monitoring includes evaluating the production records, nutrition and environmental conditions.

The second leg, biosecurity, begins with minimizing disease risks to the unit from introducing new stock through quarantine and testing and the use of "pathogen-free" semen. Management systems like all-in, all-out (AIAO) pig flow along with shower-in, shower-out practices for employees help eliminate pathogens. An extensive disinfection program for facilities, transport vehicles and equipment is essential, along with employee education and a good dose of common sense.

Vaccination is the third leg and requires the integration of information from the monitoring and biosecurity programs to develop the "best" program.

Remember that the world's best vaccination program can't make up for poor management.