Prevalence of serum antibody titers against canine distemper virus and canine parvovirus in dogs hospitalized in an intensive care unit

Effect of maternally derived antibodies on two commercial vaccines in changes of serum antibody titres against distemper in puppies

BACKGROUND

Maternally derived antibodies (MDA) have protection against canine distemper virus (CDV) in the first weeks of puppies' life. However, MDA decreases with age. The most important and effective factor on immunization is timely vaccination. But in recent years, there were some outbreaks of CDV among puppies in Iran and this problem could be related to vaccine failure.

OBJECTIVES

The aim of this study is to evaluate the possible effect of MDA titre on vaccines against CDV and the efficacy of two commercial vaccines by using the enzyme-linked immunosorbent assay (ELISA).

METHODS

In this regard, 24 healthy 8-week old terrier puppies were selected and divided into three identical groups based on a randomized, double-blind comparative trial. The control group was injected normal saline, and group A was vaccinated by the vaccine namely Biocan L (Bioveta, Czech Republic), and the group B was vaccinated by the other vaccine called Duramune Max 5 + LCI/GP (Fort Dodge Animal Health, USA). The vaccines were used for the puppies between 8 and 16 weeks of age and in every 4 weeks.

RESULTS

The results showed that the response of both vaccines was satisfactory, and no significant difference was observed between them. Moreover, the MDA in the control group reached an unprotective level in all puppies prior to their 14 weeks of age. In the vaccinated groups, after the second vaccine, all puppies in both groups reached protective levels.

DISCUSSION

This is the first study on evaluation of two commercial vaccines in changes of serum antibody titres against distemper in puppies in Iran.

CONCLUSION

It is recommended that veterinarians during consulting use the ELISA to measure antibody titres to optimize the vaccination schedule and reduce the cost of vaccination failure. This is of paramount importance for puppies.

Prevalence of Serum Antibody Titers against Core Vaccine Antigens in Italian Dogs

Canine vaccination is the main tool for preventing dangerous and widespread diseases. The strongly recommended (core) dog vaccines are against Canine Parvovirus type 2 (CPV-2), Canine Distemper Virus (CDV), and Canine Adenovirus (CAdV-1), but vaccination protocols should be tailored to dog lifestyles. Vaccination guidelines suggest vaccinating adult dogs no more frequently than every 3 years using modified live (attenuated) vaccines (MLV), thus obtaining a long-lasting (sometimes throughout life) specific protection in many but not all animals. The aim of this study was to determine the actual levels of seroprotection against CPV-2, CDV and CAdV-1 in a cohort of Italian dogs by using the in-practice test VacciCheck. A total of 1,027 dogs (951 vaccinated and 76 unvaccinated) were analyzed for Protective Antibody Titers (PATs) against CPV-2, CDV, and CAdV-1. Differences related to sex, age, breed size, health status, and time elapsed since last vaccination were evaluated. Half of the entire canine cohort (50.6%) had PATs for all three viruses (68.5% considering only vaccinated dogs). In particular, 90.8% of dogs were protected against CPV-2, 68.6% against CDV, and 79.8% against CAdV-1. Most dogs remained protected for 3 years after vaccination or longer. Revaccination on a 3-year basis can then be recommended for core MLV vaccines without altering individual's seroprotection or even herd immunity.

Update on Canine Parvoviral Enteritis

Canine parvoviral enteritis is one of the most common causes of morbidity and mortality in dogs worldwide. Tests can detect viral antigen in feces, and characteristic decreases in total leukocyte, neutrophil, and lymphocyte counts can increase the index of suspicion in affected cases and can be used to prognosticate morbidity and mortality. The standard of care for infected animals includes IV crystalloid and sometimes colloid fluids, antiemetics, broad-spectrum antibiotics, and early enteral nutrition. Vaccination induces protective immunity in most dogs. Vaccination, along with limiting exposure in young puppies, is the most effective means of preventing parvoviral enteritis in dogs.

Canine parvovirus vaccination and immunisation failures: Are we far from disease eradication?

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Despite extensive vaccination, canine parvovirus (CPV) still represents one of the major causes of pups’ mortality.

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CPV immunisation failures occur frequently and recognize different reasons.

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Interference by maternally-derived antibodies is the main cause of CPV immunisation failures.

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Eradication of CPV infection is a challenge for the future, but it will not be achieved in a short time

Despite extensive vaccination, canine parvovirus (CPV) remains a leading infectious cause of canine mortality, especially among juveniles. This review provides an update on CPV vaccine types and vaccination protocols. The design of CPV prevention strategies and vaccination programs with a goal of herd immunity has been hampered by deficiencies of studies that model companion animal viral infections and inform an understanding of the basic reproduction number. However, the most important issue in eradication of CPV disease is represented by immunisation failures including: i) the presence of interfering titres of maternally-derived antibodies; ii) the presence of non-responders; and iii) possible reversion to virulence. In contrast, the role of the CPV variants in immunisation failures is widely debated. Taking into account the reduced circulation of canine distemper virus and canine adenovirus type 1 in countries where extensive vaccination is carried out, more effort should be made to aim for CPV eradication, including antibody testing to determine the optimal time for vaccinations of pups and adults and homogeneous vaccine coverage of dog population.

Antigenic analysis of genetic variants of Canine distemper virus

Canine distemper virus (CDV) is an RNA virus of the genus Morbillivirus within the family Paramyxoviridae. CDV produces multi-systemic disease in dogs and other terrestrial carnivores. With the development of modified live vaccines in the 1950s and 1960s, the disease, with a few exceptions, has been successfully controlled. However, recently the cases of CDV in vaccinated dogs have been increasing throughout the world, including the United States. There are many reasons that can lead to vaccine failure, including antigenic differences between the vaccine strains and the currently circulating wild-type strains. Currently, there are at least three genetically different CDV lineages circulating in the US. Therefore, in this study, we evaluated various wild-type CDV and vaccine isolates to determine if the genetic differences observed among various strains result in significant antigenic differences based on changes to the neutralizing epitopes. The results of a cross-neutralization assay revealed that there are antigenic differences among the tested CDV wild-type isolates as well as between the tested isolates and the vaccine strains currently used in the US. Therefore, these results suggest the need to develop an updated CDV vaccine.

Long-lived immunity to canine core vaccine antigens in UK dogs as assessed by an in-practice test kit

OBJECTIVES

To determine the utility of an in-practice test kit to detect protective serum antibody against canine distemper virus, canine adenovirus and canine parvovirus type 2 in a sample of the UK dog population.

MATERIALS AND METHODS

Serum samples from 486 dogs, last vaccinated between less than 1 month and 124 months previously, were tested with the VacciCheck™ test kit for protective antibodies against distemper, adenovirus and parvovirus type 2.

RESULTS

A high proportion of the dogs tested (93·6%) had protective antibody against all three of the core vaccine antigens: 95·7% of the dogs were seropositive against canine distemper virus, 97·3% against canine adenovirus and 98·5% against canine parvovirus type 2. The small number of dogs that were seronegative for one or more of the antigens (n = 31) may have had waning of previous serum antibody or may have been rare genetic non-responders to that specific antigen.

CLINICAL SIGNIFICANCE

UK veterinarians can be reassured that triennial revaccination of adult dogs with core vaccines provides long-lived protective immunity. In-practice serological test kits are a valuable tool for informing decision-making about canine core revaccination.