The biggest problem in protecting a puppy against this infection sarcastically stems from the natural mechanism of protection that has evolved. Newborns obtain their immunity from their mother’s first milk, the colostrums.
Canine parvovirus infection in dogs called ‘Parvo’ causes acute gastroenteritis resulting in blood mixed diarrhea, vomition and sometimes acute myocardial inflammation in puppies. Infected animal’s experience severe dehydration and die if appropriate treatment is not given timely. Dogs of all age and breeds are susceptible to the disease but young puppies are more vulnerable when exposed to infected dogs, their feces, or objects and areas contaminated with their feces. Parvovirus is extremely enduring and resists in most household disinfectants. It will survive for months on the premises.
To frontier environmental contamination and spread to other susceptible animals, dogs with confirmed or suspected CPV enteritis must be handled with strict isolation procedures and disinfection of the premises should be done regularly. For effective inactivation of the virus, 1:32 dilution of bleach should be left on all the exposed surfaces for at least twenty minutes before being rinsed with water. Bleach solution can even be applied on bedding, dishes, kennel floors and other impervious materials that may be contaminated. It can also be used as footbaths and to wash the quarters of infected animals. Still, it’s vital to isolate young puppies as much as possible from other dogs and from potential sources of infection till they complete the vaccination course.
There are several commercially prepared attenuated live vaccines available which protect against all the strains of the canine parvovirus. Commercially prepared vaccines are safe and do not cause disease. Vaccine failure could occur and is primarily due to interfering level of maternal antibody against the canine parvovirus. This communication is focused over vaccines and vaccination schedule that help to avoid the occurrence of parvovirus infection in dogs.
Role of maternal antibodies
The biggest problem in protecting a puppy against this infection sarcastically stems from the natural mechanism of protection that has evolved. Newborns obtain their immunity from their mother’s first milk, the colostrums. This milk contains the mother’s antibodies against parvovirus, and until these antibodies wane to ineffective levels they will shield the puppy against infection. The problem is that they will also inactivate the vaccine. High levels of maternal antibodies present in the puppies’ bloodstream will block the effectiveness of a vaccine.
The stage at which puppies can competently be immunised is proportional to the titer of the mother and the effectiveness of transfer of maternal antibody. When the maternal antibodies drop to a low level in the puppy, immunisation by a vaccine will work. The complicating issue is that there is a period of time from several days to several weeks during which the maternal antibodies are not sufficient to provide protection against the infection, but high enough to not allow the vaccine to work. This is often the time once despite being vaccinated; a puppy can still contract parvovirus infection. The length and timing of this window of susceptibility is different in every puppy in every litter.
The next problem is that the age at which the vaccine can be effective is different for each individual puppy. Different vaccination protocols have been designed to help protect the widest range of dogs. By using these protocols, we will be vaccinating some dogs that are not capable of responding and revaccinating some dogs that have already responded and developed a high titer. By using quality vaccines and an aggressive vaccination protocol, we can make this window of susceptibility as small as possible. The widely recommended protocol is to immunise puppies against parvovirus starting at 6-8 weeks of age, and revaccinating every 3 weeks until the puppy is 16-20 weeks of age. A booster is given at one year of age and every 1-3 years thereafter.
Parvovirus Vaccine for Dogs
Owing to the infectious and very fatal nature of the parvovirus infection, the Canine parvovirus vaccine is considered a core vaccine, meaning all dogs should receive this vaccine. Treatment is supportive and potentially costly and dogs left untreated usually succumb to death. To prevent and control CPV, a highly effective vaccine against the virus is readily available and there is no excuse for not vaccinating. Modified live vaccine is recommended at 6-8, 10-12, and 14-16 week of age, followed by a booster administered 1 year later and then every 3 year. Inactivated vaccines are indicated in pregnant dogs or colostrums deprived puppies vaccinated before 6-8 week of age rather than a modified live because of potential damage by CPV to myocardial or cerebellar cells.
High Titer Vaccines: answer to maternal antibodies interference
Newer high titer-low passage vaccines are narrowing the window of susceptibility. The term “high titer” refers to the amount of virus in the dose of vaccine and means that these modified live virus vaccines contain a higher number of virus particles (high titer), which are less attenuated than those in the average vaccine. That means high titer-low passage vaccines can generally elicit an immune system response in young animals that have a maternal antibody level that would normally prevent them from responding. When the puppy is vaccinated, maternal antibody binds the virus present. If a high titer vaccine is used, there is still virus left over after all the maternal antibody has been used up. This extra virus can then stimulate the puppy’s own immune system. High titer vaccines commonly produce full protection by age of 12 weeks. It should be noted that giving vaccine more frequently than every 2 weeks will cause interference between the two vaccines and neither can be expected to be effective. This includes giving vaccines for different infections. Vaccines should be spaced 2 to 4 weeks apart. It is commonly held that puppies need a certain number of vaccines for protection to be achieved. The number of vaccines given has nothing to do with protection. For protection to achieve, vaccine must be given when it can penetrate maternal antibody.
Vaccines available in India
Major canine vaccines available in India manufactured by various pharmaceuticals:
Parvo: Duramune KF-II®, Megavac-P (live)®, Megavac-P (inactivated)®, Nobivac-Parvo-C®, Parvocin® and Vanguard-CPV®
Rabies: Raksharab, Rabigen, Nobivac-Rabies, Rabigen, Rabvac 1, Rabvac vet, Defensor 1
Corona: Vanguard CV, Duramune CvK, Megavac CC
Combined: Nobivac-DHPPi+L, Megavac 6, Canigen DHPPi/L, Vanguard 5L, Duramune max 5/4l
Vaccinations timeline for your dog
Undoubtedly, your veterinarian is always the best guide for making vaccination decisions, however shown below is a general vaccination schedule for the ‘average’ dog which will help you to get your pet properly vaccinated.