This review intends to provide veterinarians with key facts and information relevant to serological testing of individual dogs and cats in the clinical setting. Specifically, this paper addresses the role of antibody testing for the core, vaccine-preventable diseases canine distemper virus, canine and feline parvovirus, and canine adenovirus.
Why did the veterinarian order the vaccination of the puppy with core vaccine component, 3 times at 3-week intervals?
For over a decade canine vaccine has been categorised into core, non-core and non-recommended groups, with canine distemper, parvovirus and adenovirus considered as the core vaccine components. These categories have been further developed and currently form the basis of the World Small Animal Veterinary Association (WSAVA) Guidelines for the Vaccination of Dogs and Cats.
With regard to vaccinations of puppies, the WASVA guide lines recognizes that maternally derived antibody (MDA) significantly interferes with the efficiency of most current core vaccines administered to pups and kittens in early life. The vaccine consists of attenuated living virus and therefore the antibodies identify it and lead to its destruction. As the level of MDA varies significantly amongst litters, the guidelines recommend the administration of multiple core vaccine doses to pups and kittens, with the final dose of these being delivered at 16 weeks or older and then followed by a booster at 6- or 12-months of age.
Vaccination of neonates and infants is problematic with two main issues: the immature immune system of neonates and the presence of inhibitory maternal antibodies.
When a pup is born, its immune system is not fully developed making it susceptible to a variety of infectious agents. Fortunately, this is not the case for most of the neonatal, as they can receive passive protection from their mothers through maternal immunity.
Passive immunity occurs by the passage of antibodies to the fetus through the placenta (~3%), and more significantly, by the absorption of maternal antibodies of the new born through the colostrum (~97%). Defined as the first 12-24 hours of milk flow following birth, colostrum is a highly concentrated mixture of large protein antibody molecules, vitamins, electrolytes, and nutrients. The pup can absorb the colostral antibodies into its blood system through the intestine only for its first days of life; the amount of absorption depending on the strength of each individual pup.
Unfortunately, the maternal antibodies will break down through natural aging of up to approximately 8-20 weeks. At this point the MDA decaying (Blue line in the graph below) may not provide optimal protection and may even act as inhibitor to the effectiveness of the vaccine (In between the two interrupted lines ~8-16 weeks). This situation is highly risky for the exposed and unprotected puppy. To avoid this situation the core vaccines are being given at 3-4 point intervals, as shown in the graph below.
Initial Vaccination (Dogs 16 Weeks of Age)
- Beginning as early as 6 weeks of age, the puppy is administered with sequential doses of a combination vaccine at an interval of 2 to 4 weeks until at least 16 weeks of age.
- Dogs that are 16 weeks of age when presented for initial vaccination should receive a second dose 2 to 4 weeks later.
- NOTE: Dogs residing in a HIGH-RISK environment may benefit from receiving a final dose at 18 to 20 weeks of age. HIGH RISK is a subjective assessment applicable to dogs residing at locations in which the incidence of CDV and/ or CPV is considered to be high; it may also include puppies known to have significant exposure to other dogs or contaminated environments.
- A single dose of a combination vaccine is administered within 1 year following the last dose in the Initial Vaccination series. Subsequent boosters should be administered at intervals of 3 year or longer.
- Measuring antibody levels (quantitative or qualitative) provides a reasonable assessment of protective immunity against CDV, CPV, and CAV2.
A vet, having encountered a large number of kittens suspected of Panleukopenia (FPV), approached us at Biogal. The kittens in question were of a private home cattery. The owner noticed that two of the kittens were in a very poor condition. The two sickly kittens were brought to the clinic for hospitalization with a suspicion of FPV. None of the kittens had been vaccinated.
The suspected disease was due to a compatible blood results (Low white blood cells) and suggestive clinical signs.
Slowly, at the cattery, other kittens began to show signs of lethargy, diarrhoea and a lack of appetite.
Feline Panleukopenia Virus (FPV), also known as Feline Infectious Enteritis, Feline Parvoviral Enteritis and Feline Ataxia, is a viral infection affecting cats. It is caused by Feline Parvovirus, Fast progressive with an incubation time of ~2-10 days, highly contagious and can be fatal. The name Panleukopenia comes from the low white blood cell count (Leucocytes) exhibited by affected animals.
Knowing how fatal and highly contagious FPV can be, the owner knew that something had to be done for the sickly and the still healthy kittens. Early treatment and possible isolation of the unaffected kittens, would be wise.
She was glad to hear that the exposed kittens could be differentiated from the healthy ones by using Feline VacciCheck, a simple in-house blood test.
Feline VacciCheck measures IgG antibodies specific to FPV. IgG antibodies rises within days to weeks after exposure to the disease or to vaccination and persist for a long period. In cases with no vaccination history and suggestive clinical signs of the disease the presence of IgG can support the diagnosis.
In young kittens the presence of IgG could be from Maternally Derived Antibodies (MDA). The MDA passively pass to the kittens through colostrum on their first hours of life and disappears within a few weeks from their blood stream.
In this case none of the kittens had been vaccinated. Most of the kittens were estimated to be around 5 months old, where the presence of MDA is less likely. Therefore, the presence of IgG antibodies probably will indicate exposure and will require a close monitoring of the kittens who are at risk and proper disinfection actions to the whole cattery.
Feline VacciCheck testing was run on eleven kittens in the cattery:
The other two antibodies tested are two highly contagious respiratory diseases: Feline Herpes Virus (FHV) and Feline Calici Virus (FCV).
The kittens who showed positive results to all the 3 pathogens, are perhaps those with MDA presence (younger kittens) or those who were exposed to all these 3 diseases (which is very likely in a very crowded cattery).
The two negative FPV kittens were isolated from the others. The whole cattery was properly disinfected with solution of diluted bleach.
All the other kittens, positive FPV IgG, were closely monitored. Being positive means that they had been exposed to the disease but would not necessarily develop the disease. This would depend on the individual immune system of each kitten.
After further investigation, these results were validated using a PCR (Biogal PCRun) technic which confirmed the presence of the panleukopenia virus in all positive kittens.
In total, five out of the nine positive kittens who were closely monitored showed clinical signs and were treated promptly. Thanks to early diagnosis and treatment, the recovery was quick and successful for all five kittens.
Most puppies are vaccinated several times at 6, 9 and 12 weeks, as it is known that maternally derived antibodies can cause a vaccination to fail. However, is that sufficient? How do you know whether your dog is protected?
Pups are given, right after birth, via the first mother's milk, (colostrum) antibodies, that will protect against infectious and fatal diseases. These so-called maternally derived antibodies are temporary and disappear gradually, but can be present in the blood of the pups for up to 20 weeks or longer. If, however, the mother dog has no, or too few antibodies, the pups will not get them through the colostrum and are unprotected! It is important to protect puppies at the right time by means of a vaccination that stimulates the body to produce antibodies. This ensures permanent immunity.
The goal of a vaccination is to make dogs immune to certain diseases. However, it is a misconception to think that all animals, that have been vaccinated, are actually protected. A vaccination does not automatically lead to protection in young animals, that are still protected by maternally derived antibodies. In the Netherlands and Belgium, pups are usually vaccinated at 6, 9 and 12 weeks. The last vaccine of the puppy vaccination schedule will be administered around the age of 1 year, and then every 3 years they are vaccinated against infectious hepatitis, parvo and distemper.
Most pups are vaccinated several times, because it is known that maternally derived antibodies can block a vaccination. By administering a vaccine regularly every 3 weeks, there is a chance that one will catch. The problem lies in the fact that most puppies get their last vaccination at 12 weeks. As maternal immunity can last up to 20 weeks, and sometimes even longer, there is a big chance that they will walk around unprotected for up to 1 year, the age at which they receive the last vaccination of the vaccination schedule. People mistakenly think that their dog is optimally protected by this vaccination, but there is still at risk of contracting and spreading diseases. The dogs will then go unprotected to dog schools, boarding kennels, shows, competitions, animal events, dog parks and so on.
Optimal vaccination schedules
It would be much better, and more responsible, to adjust the current vaccination schedule according to the vaccination guidelines of the WSAVA. The WSAVA is a scientific committee, which sets out guidelines worldwide regarding the vaccinations of dogs and cats. In these guidelines, it is stated, that among other things, it is not wise to administer the last vaccination before the age of 16 weeks. There are two possibilities:
- A titer determination at 20 weeks. If the result is positive, the dog does not need to receive extra vaccination and the animal can be tested again after a certain period, depending on the result.
- To advance the vaccination normally given at 1 year, to 26 weeks. This is to prevent the animal from walking around unprotected until the age of 1 year.
Most puppy buyers receive a puppy that has been vaccinated once in the litter. Such a puppy can be tested 3 weeks after the vaccination. At that moment, it is not always clear whether the antibodies, that are being measured, come from the mother or from the vaccine. Therefore, a few weeks later, a new titer test is required. If the titers have dropped, then it is certain that these are maternally derived antibodies. Depending on the level of the antibodies (antibody titers) at that time, the pup can then be vaccinated or be retested at intervals of a few weeks, when they are sufficiently low to vaccinate successfully. If the titers remained the same, then this is a sign that the vaccination has been successful. Unfortunately, most puppies in the Netherlands and Belgium are usually only vaccinated against distemper and parvo, so they still have to be vaccinated with a cocktail that also contains infectious hepatitis.
The best and most effective method is to titer test a pup, who has not yet been vaccinated, just before it leaves the litter. If the test shows that sufficient maternally derived antibodies are still present, vaccination is pointless, as the antibodies will neutralize the vaccine. You would then retest the pup, who is probably already with the new owner, after about 3 weeks. If the level of antibodies has declined below the protective level and the level at which a vaccination can immunize, a cocktail containing modified live viruses of infectious hepatitis, parvo and distemper has to be administered.
Subsequently, a titer test is performed about 3 to 4 weeks after this vaccination, to see if the puppy actually has enough antibodies in the blood, and is protected against the diseases mentioned. If this is the case, it means that the dog is immunized and fully protected against the mentioned diseases, by just one vaccination. As the animal is still very young and the immune system has not yet fully developed, a year later it makes sense to test it again to see if the protection is still good. If this is the case, titer testing can be performed triennially, according to the WSAVA guidelines.
The most commonly used titer test is VacciCheck. This is a reliable in-house test which can be performed by the veterinarian himself. Only a very small drop of blood is needed and the result is known within half an hour. The veterinarian must indicate in the vaccination pet passport how long the dog will be protected and thus, a validity period is linked to the declaration, according to Dibevo, KNMvD, NVWA and KMSH.
Over the years, Professor Ronald Schultz has been a pioneer in creating vaccination guidelines for our pets.
So when Professor Schultz comes up with the statement “Be Wise and Immunize, But Immunize Wisely”, what is the take home message?
A Concept Change for Pet Vaccination
The routine administration of vaccines in dogs and cats has been one of the most significant factors in the consistent reduction of serious dog and cat infectious diseases.
Although all veterinarians agree vaccines are necessary, the frequency in which some of them are given, is now debated.
It is known that dogs and cats, after vaccination, often maintain protective antibody to what is called the “core diseases” - Canine Hepatitis, Parvovirus and Distemper and Feline Panleukopenia, Herpes and Calici Virus for three or more years. So, our dilemma is knowing that we may not need to revaccinate our pets for core vaccines, how can we know that the antibody levels of our pets through vaccination are indeed adequate?
Titer Testing to Determine Protection for Our Pets
Antibody or titer testing can be used to show levels of protection after vaccinating our pets with core vaccines.
Therefore, when an antibody is present, there should be no need to revaccinate.
How Often to Titer Test?
Professor Schultz has offered the following advice:
“Neither a titer nor annual vaccination is necessary every year because of the core vaccines’ duration of immunity. However, a blood sample taken yearly from an animal for a titer check is preferential to an unnecessary vaccination as a vaccine may cause harm.”
The Canine and Feline VacciCheck are Core Vaccine Tests
One of the titer tests available and, easily performed by vets, in their clinics, is VacciCheck.
VacciCheck tests for your pet’s antibodies and can determine if a dog or cat needs an additional core vaccine vaccination. This may save the dog or cat unnecessary vaccinations.
VacciCheck also confirms if puppies or kittens have received immunity from vaccination.
Also unique about VacciCheck, results can be received on the same day.
So vets now have a quick and simple test that can be performed in their clinic, at a reasonable cost to the pet owner.
It is no wonder that The World Small Animal Veterinary Association recommends in clinic titer testing, such as VacciCheck.
Recently, a veterinarian from a large clinic contacted me as he suspected Parvo disease in "Tommy”, a five month old mixed breed dog.
Tommy was adopted a few months ago from a shelter and since then he has begun receiving all three-core vaccines - Canine Parvo Virus (CPV), Canine Distemper Virus (CDV) and Canine Adeno Virus (CAV), according to the recommended protocol (which is from the age of 8 weeks, at 3 week intervals).
About a week after receiving his last vaccine injection, Tommy began to show suspicious signs of Parvo - loss of appetite, lethargy and watery diarrhea. A blood count test showed no Parvo signs. Tommy was hospitalized because of his poor condition, and still the suspicion for Parvo.
We ran Tommy’s blood sample using VacciCheck in order to get the full picture of his immune status and response to the vaccines. We realized Tommy's immune system responded well to the distemper vaccine and to the Adenovirus vaccine components. However, and amazingly so, no response to the Parvo virus component was seen.
A possible reason for not responding to the vaccine, may be genetically based; Non-Responders who cannot respond specifically to one of the vaccine components (1: 1000 for Parvo, 1: 5000 for Distemper, and 1: 100,000 for Adenovirus). Potential additional reasons may be the presence of maternal antibodies that interfere with the vaccine (which is not common at the age of 5 months), or any other cause like improper vaccine manufacturing or storage which can lead to a non-response to the vaccine.
Two days after being hospitalized, Tommy’s blood count tests showed clear signs of Parvo (↓↓↓Whole Blood Count).
We are glad to note that Tommy recovered. Sufficient Parvo antibodies were found by using VacciCheck, showing the unlikelihood that Tommy is a genetic Non-Responder.
Parvo is a very contagious disease, with high morbidity and mortality rates. The disease breaks out very quickly by attacking dividing cells, such as the cells of the intestine, causing severe diarrhea and bone marrow cells, which aggravate the condition due to secondary infections.
Untreated dogs could die within 2 days after signs of illness appear. The survival percentage in treated dogs is 68% - 92%.
My take home message: in order to be sure that your beloved puppies are protected from this severe disease, it is possible to verify protection by a simple examination, and so avoiding unnecessary suffering and long and expensive hospitalization.
My journey to the alternative healthcare model, interestingly began with my late Miniature Bull Terrier, Molly’s Titre Test in 2008.
Back then, before in-house Titre Tests like VacciCheck were available, a Titre Test was not only expensive, but treated with suspicion and scepticism by Vets.
The option for Titre was only presented to Molly as I was anxious about giving her a booster. I’d read many articles in the consumer dog press that highlighted how some dogs become ill after a booster jab.
As I had constantly ignored the reminder letters to booster, our then conventional vet practice phoned me. The vets were highly concerned that Molly had not been boostered since her puppy shots.
She was aged six in 2008 and they were correct in that she had never had a booster. Listening to my concerns, our vet reluctantly suggested a Titre Test.
I was advised it would cost £380.00 and that I would most likely have to pay for a booster jab as well, as Molly was sure to need one.
Our vet was convinced that Molly’s serological results to the core diseases for dogs, Canine Distemper virus (CDV); infectious hepatitis (ICH) and canine parvovirus (CPV), would be low and she would need a booster.
Imagine the Vet’s surprise when Molly’s Titre Test results showed results of her serological immunity scored as high, for all three diseases.
Molly proved that six years on from her first puppy shots, given at eight and twelve weeks, that her immunity was still high. She did not need a booster!
This questioned the school of thought that vaccines’ DOI (Duration of Immunity) was less than three years. Indeed back in 2008 the view was that boosters ought to be administered annually!
The landmark moment came when in 2013 the WSAVA (World Small Animal Veterinary Association) revised its original vaccination guidelines (published in 2007) to include the use of Titre Testing in lieu of annual boosters.
In its latest edition (2017), the WSAVA in fact stresses the value of, and recommends Titre Testing.
Just as Molly’s Titre testing proved, the topical issue of Duration of Immunity (DOI) has been shown to last from initial puppy shots, often for a lifetime.
Offering Titre Tests, vets can reach out to owners like myself who do not believe in doing something (ie giving a booster jab) when it’s unnecessary.
The key principle behind natural ‘holistic’ medicine is to adopt the ‘Precautionary Principle’ keeping the toxin load from environmental stressors – arguably vaccines, flea treatments, wormers, overuse of medications like antibiotics, steroids and pain killers - to a minimum.
This also means balancing and reducing the environmental stressors that are present in the foods we eat, the air we breathe, and the water we drink.
I named Molly’s successor Prudence - as it’s not only a ‘old’ English name, suited to her breed, but it is also to remind me - be prudent.
Aged 15 weeks, Prudence arrived into the UK under the PETS scheme. She had had her first puppy shots at eight weeks, then the Thimerosal free rabies shot at 15 weeks allowing her entry into the UK.
Prudence went for her vet check and a discussion about her vaccines, which involved Titre Testing her, using VacciCheck at 16 weeks.
Prudence had seroconverted! Her level for canine parvovirus (CPV) was high; for canine distemper virus (CDV), medium; and for infectious hepatitis (ICH), medium.
As she displayed adequate immunity, there was no need to give her any more shots. In line with my study, I wanted to keep environmental stressors to a minimum, especially at such a young age.
Thanks to the WSAVA VGG group, the on-going acceptance by Vets of Vaccicheck’s in house Titre testing, s arguably one of the biggest steps forward in modern Veterinary health care.
It allows owners to manage and take control of their pets’ immunity, and not unnecessarily over vaccinate.