Canine Vaccination Research Articles

Enzyme-linked immunosorbent Assay for detecting of antibody to canine distemper virus

Serum neutralisation test (SNT) has been established for evaluating canine distemper vaccination, but until now SNT was rarely used due to the need for continuous tissue culture facilities and requires 3 days to perform. For detecting antibody to canine distemper virus, an enzyme-linked immunosorbent assay (ELISA) is relatively simple and rapid seroassay. ELISA for canine immunoglobulin (Ig) G antibodies to canine distemper virus (CDV) was developed by using Onderstepoort strain of canine distemper virus as coating antigen. Rabbit anti canine IgG labelled with horse radish peroxidase was used as the conjugate, while phenylenediamine dihydrochloride (OPD) was used as the substrate. The ELISA results were then compared with the results of the SNT, using the sera of 312 random-source dogs from West Java. The two test-results had a high degree of correlation. Very few discrepancies occurred and most of these were at the lower limits of each test. When the sera were tested at 1 : 100 dilutions, there was a 95.5% agreement between the ELISA and SNT. Their sensitivity and spesificity were 83.9 and 98.4%. Titrated SNT and ELISA also were performed on sera from 7 dogs whose lifetime medical histories were known. The antibodies were inclining up after two months of post vaccination, where the titre was not in zero/lower position at the day of vaccination. However, antibody zero or low position were found at 28 days post vaccination. All of the results indicated that ELISA can be used for evaluating antibody to canine distemper virus response, replacing the SNT. Key Words: ELISA, Serum Neutralization Test, Distemper, Dogs

Complex genetic structure of the rabies virus in Bangkok and its surrounding provinces, Thailand: implications for canine rabies control

Dog vaccination and population management have been suggested as priorities in attempts at disease control in canine rabies-endemic countries. Budget limitations and the complexity of social, cultural and religious variables have complicated progress in the developing world. In Bangkok, Thailand, an intensive canine vaccination and sterilization programme has been in place since November 2002. Our objective was to determine if the rabies virus could be mapped according to its genetic variations and geographical location on the small localized scale of Bangkok and its surrounding provinces. Phylogenetic characterization of 69 samples from Bangkok and five neighbouring and two remote provinces, by limited sequence analysis of the rabies virus nucleoprotein gene, distinguished six different clades. Rabies viruses of four clades were intermixed in Bangkok and in the surrounding highly populated regions whereas the other two clades were confined to rural and less populated provinces. Such a complex pattern of gene flow, particularly in Bangkok, may affect the outcome of canine control programmes.

Retrospective: Animal attacks and rabies exposures in Thai children

Over 50% of animal bites and potential rabies exposures in Thailand are in children and they also have the more severe injuries due to inexperience, smaller size and less ability to fend off attacks. Potential rabies exposures and animal bites are common in Thailand. Majority of these are in children where the extent of the injuries is also much more severe. The bitten areas correlate to the age of the children and level of the bitten animal head. These are areas noted for a higher risk of infection with rabies virus and shorter incubation periods. The vast majority of bites are due to dogs (86%) of which 74.6% are stray or community-owned animals. The prevalence of dog bites shows no seasonal variation in adults but there are two peaks during school vacation period for children. Extensive educational efforts directed at the Thai public are responsible for the rapid presentation of victims for post-exposure treatment. The dramatic reduction of human rabies deaths in Thailand during the last decades was achieved largely by the provision of expensive WHO standard post-exposure treatment, utilizing modern tissue culture vaccines and immunoglobulins. Canine and feline rabies is nevertheless still endemic and not likely to be controlled or eliminated till sustainable humane methods of dog population control and comprehensive countrywide canine rabies vaccination become possible through government policy.

Vaccination coverage and epidemiological parameters of the owned-dog population in Thungsong District, Thailand

Canine rabies vaccination is delivered in Thungsong District, Thailand, as an annual campaign between March 1 and 31, and also at other times through private veterinary clinics, para-veterinarians and health-care staff residing in the villages. The current questionnaire-interview survey was conducted between June 23 and July 18, 2002 to determine: rabies-vaccination coverage amongst the owned-dog population; basic dog-population information; and community awareness about rabies. The modified expand programme on immunization cluster-survey method was used to collect information about dog demography and management characteristics. Household knowledge about rabies and sources of rabies information were assessed. Vaccinated dogs were identified from vaccine certificates or owner reports confirmed by vaccinators. Seventy percent (95%CI 62–78) of 364 eligible owned dogs were vaccinated within the 6 months prior to data collection. Of these 255 vaccinated dogs, 44, 21, 13, 17 and 5% were vaccinated through the annual vaccination campaign, veterinary clinics, para-veterinarians, other vaccinators and owners, respectively. Fifty-four percent of households owned dogs. The sex ratio in dogs was 2 males per female; the dog: human ratio was 1: 4.6 with an average of 0.9 dogs per household (1.7 dogs per dog-owning household). Most dogs roamed freely and these were less likely to be vaccinated compared to dogs being kept on premises or on a leash. Almost all households were aware of rabies and the need for dog rabies vaccination as a control method. Seventy-six percent believed that rabies only occurred in summer. There was little awareness about cat rabies amongst households. Vaccination coverage in the total dog population clearly has not yet reached the 80% target level set by Thailand's official rabies-control programme. Improved effectiveness of the owned-dog rabies-vaccination campaigns in each community is needed–perhaps by more community education about dog management or by better management of ownerless dogs.

Canine rabies DNA vaccination: a single-dose intradermal injection into ear pinnae elicits elevated and persistent levels of neutralizing antibody

Rabid dog exposures cause >99% of human rabies deaths world-wide. In developing countries, where dogs are the viral reservoir, the 30–50% vaccination coverage of dog populations is insufficient to break the disease transmission cycle. In addition, many vaccines currently used in developing countries fail to maintain detectable levels of neutralizing antibody. The poor vaccination coverage with inadequate vaccines, in addition to the difficulty in locating dogs for booster vaccinations, suggest that an inexpensive vaccine that elicits long-term immunity after a single-dose vaccination could improve control of canine rabies in developing countries. One solution could be a DNA vaccine. This study was designed to evaluate in dogs the ability of different methods of a single-dose DNA vaccination to elicit enhanced levels of neutralizing antibody. Intradermal (i.d.) vaccination into ear pinnae elicited elevated and long-lasting levels of neutralizing antibody. Minimal or undetectable levels of neutralizing antibody were detected after vaccination into quadriceps muscle, gene gun vaccination into ear pinnae or i.d. vaccination into the neck. Intramuscular (i.m.) or gene gun vaccinations did not “immunologically prime” a majority of dogs vaccinated by these routes. The passive transfer of sera from dogs that had been vaccinated i.d. in ear pinnae protected mice against rabies virus challenge. A single-dose i.d. rabies DNA vaccination into ear pinnae could aid in the control of canine rabies in developing countries.

Ferrets in veterinary practice

Ferrets (Mustela putorius furo) show up with increasing frequency in veterinary practice. Originally domesticated for hunting of rodents and rabbits, they became very popular pets which require legal permission though and the further fulfillment of various husbandry needs. Ferrets have to be maintained on a high protein diet which in practice is often done with commercial feline products. Physical examination is similar to dogs and cats whereas the frequent occurrence of non-specific symptoms require further diagnostic investigation including blood sampling, radiology, ultrasound or exploratory laparatomy. The preferred anaesthetic method is the direct face mask induction and maintenance using isoflurane without prämedication. Special attention of veterinarians has to be paid to canine distemper vaccination, the specialized reproduction physiology of the females (jills) which can develop, if unmated, a persistent oestrus with fatal consequences of hyperestrogenism, as well as the frequent occurrence of further endocrine disorders, congestive cardiomyopathy and gastrointestinal diseases.

Canine and Human Rabies in Cameroon

.Keywords: Rabies, canine, human, distribution, control, Cameroon. This paper is a retrospective review of recorded rabies and antirabies activities in Cameroon from 1990 to 1999 to determine the current state of rabies in both dogs and humans. Rabies and antirabies activities were recorded every year in Cameroon through out the 10-year study period with the highest values observed in the Centre, Littoral and West provinces which are the most urban places. A total of 38,784 suspected rabid dogs were quarantined and 129,266 pets were vaccinated against rabies. About 1.86% of the quarantined dogs died during observation while 0.85% of them were confirmed positive for rabies. The mean annual numbers of quarantined dogs and dogs that died during quarantine in the country were 3933 + 1503 and 73 + 74 respectively. However, mean annual values of 1293 + 2173, 33 + 22 and 43 + 13 were also obtained for canine antirabies vaccination, confirmed canine rabies cases and human deaths due to rabies respectively. Although, the distributions of these follow the urban/rural nature of the country, human rabies seem to be more in the rural areas contrary to canine rabies which is more urban in nature. Also, poor accessibility to the main diagnostic laboratories affected the number of confirmed canine rabies cases recorded from the various provinces. Other factors which are obstacles to effective antirabies activities in Cameroon were also discussed Trop. Vet. Vol. 20(3) 2002: 162-168

Forty years of canine vaccination

During the last 40 years vaccines have been developed that have greatly reduced the incidence of infectious diseases of dogs. In general, modified live products have been superior to inactivated vaccines for dogs. It can be expected that recombinant and/or DNA vaccines may dominate the market in the future. Although most vaccines on the market are safe and efficacious, there have been exceptions where disease was induced by vaccination or dogs were not protected. The failure of protection may in part be due to variations in individual vaccine batches. Only potency tests but not efficacy tests are required, which may not be sufficient. For example, a virus titer in a vaccine may be meaningless if the minimum protective dose is not known. Overattenuated virus (e.g., CDV-Ond or parvovirus in cat cells) may have a high titer in tissue culture but is not immunogenic. The question of frequency of vaccination of dogs should be addressed. Annual revaccinations for CDV, CPV, and CAV are probably not needed. However, it would be desirable to collect more data to support less frequent vaccinations. Annual immunization for bacterial diseases such as kennel cough, Lyme disease, and leptospirosis should continue. It also would be desirable to develop more oro/nasal vaccines, perhaps combined with newly developed vectors that are less likely to induce undesirable side effects that may be seen after parenteral vaccination. Finally a word of warning against homeopathic "nosodes" to replace tested canine vaccines. They will appear highly effective as long as the majority of dogs remain vaccinated. As soon as a nonvaccinated dog population is large enough to allow virulent agents to spread, disease outbreaks will occur and we will be back where we began 40 years ago.

Canine distemper virus DNA vaccination induces humoral and cellular immunity and protects against a lethal intracerebral challenge.

We have studied the immune responses to the two glycoproteins of the Morbillivirus canine distemper virus (CDV) after DNA vaccination of BALB/c mice. The plasmids coding for both CDV hemagglutinin (H) and fusion protein (F) induce high levels of antibodies which persist for more than 6 months. Intramuscular inoculation of the CDV DNA induces a predominantly immunoglobulin G2a (IgG2a) response (Th1 response), whereas gene gun immunization with CDV H evokes exclusively an IgG1 response (Th2 response). In contrast, the CDV F gene elicited a mixed, IgG1 and IgG2a response. Mice vaccinated (by gene gun) with either the CDV H or F DNA showed a class I-restricted cytotoxic lymphocyte response. Immunized mice challenged intracerebrally with a lethal dose of a neurovirulent strain of CDV were protected. However, approximately 30% of the mice vaccinated with the CDV F DNA became obese in the first 2 months following the challenge. This was not correlated with the serum antibody levels.

Rabies in Thailand.

The prevalence of canine and human rabies in Thailand has decreased significantly during the last decade. This has been associated with an increasing number of human post-exposure treatments. Educational efforts, mass vaccination of dogs and cats and the use of safe and effective vaccines have all made an impact. The proportion of fluorescent antibody positive dogs, among those examined for rabies averaged 54% indicating that rabies is still a major public health threat. Canine rabies vaccination is not usually performed in animals < 3 months old. However, this study revealed that 14% of rabid dogs were < 3 months old and 42% were < or = 6 months old. This is the age group most likely to interact with humans and other dogs. Our study also supports the World Health Organization's recommendation that observing suspected rabid dogs for 10 days is an adequate and safe practice.

Antibody responses of red wolves to canine distemper virus and canine parvovirus vaccination.

Twenty captive red wolves (Canis rufus), including 16 intended for release into Great Smoky Mountains National Park, Cades Cove, Tennessee (USA), and four housed at Knoxville Zoological Gardens, Inc., Knoxville, Tennessee, were evaluated for immunologic response to vaccination between June 1994 and April 1995. Wolves were vaccinated with modified-live (MLV) canine distemper virus (CDV) and canine parvovirus type-2 (CPV2). Sera were collected, and immunofluorescent staining was performed for determination of immunoglobulin titers (CDV IgM, CDV IgG, and CPV2 IgG). A capture enzyme-linked immunosorbent assay was performed for validation purposes, to confirm the reactivity of our standard diagnostic reagents with red wolf serum. All wolves produced a measurable antibody response to CDV and CPV2 vaccination. Titers against CDV and CPV2 varied widely among individual wolves, but between-litter differences in mean titers were not significant. No consistent response between the degree of response to CDV versus CPV2 vaccination was observed in individual wolves. No differences were seen between IgG responses of pups vaccinated with univalent vaccines given concurrently or during alternating weeks. Pups had an IgG response to CDV and CPV2 vaccination as early as 9 wk of age. Mean post-vaccination IgG titers against CDV were at or above the level normally measured in vaccinated domestic dogs. Mean post-vaccination IgG titers against CPV2 were below the level normally measured in domestic dogs. Adult previously-vaccinated wolves had measurable CDV and CPV2 IgG titers more than 1 yr after vaccination, but did not have significant IgG titer increases after revaccination. We conclude that red wolves are capable of producing an antibody response after vaccination with commercial canine products but that their response to CPV2 vaccination was minimal. This response can be assayed using tests developed for domestic dogs.

Further studies on rabies virus isolated from healthy dogs in Nigeria

Rabies viruses isolated from healthy dogs, were passaged in mice and adapted to cell culture. After 5–7 passages, isolated viruses were subjected to monoclonal antibody (MAb) characterization with a panel of 36 anti-nucleocapsid (NC) and 40 anti-glycoprotein (G) MAbs. The four viruses showed positive fluorescence with all NC hybridomas except MAb 422-5, confirming them as true rabies virus isolates. The anti-G MAb reactivity pattern was the same in the four isolates indicating that they belong to the same antigenic group, but were antigenically distinct from the Flury LEP rabies vaccine virus which is widely used throughout Nigeria for canine vaccination, and from other previously characterized street lyssaviruses from Nigeria.

Vaccination challenge studies with variants of street rabies virus isolated in Nigeria

In a preliminary study it was observed that adult ICR mice immunized with serial dilutions of an inactivated experimental human rabies vaccine from the Pitman-Moore (PM) vaccine virus were well protected against challenge with homologous virulent PM virus and challenge virus standard (CVS). However only one of five variant representatives in five of seven groups of 41 isolates of street rabies virus from Nigeria characterized by hybridoma monoclonal antibodies specific for the nucleocapsid and glycoprotein antigens of rabies virion was protected for by the vaccine. Guinea pigs immunized with a live attenuated low egg passage (LEP, Flury strain) vaccine currently used in canine vaccination in Nigeria protected against challenge with all five variants. The LEP vaccine protected against the variants and CVS quite well even when 1:125 dilution of the vaccine was used.

Canine parvovirus vaccination efficacy

Canine parvovirus vaccination efficacy

Experiments with a homologous, inactivated canine parvovirus vaccine in vaccination programmers for dogs.

The significance of canine parvovirus (CPV) infections as a permanent threat susceptible dogs, in particular pups, made the authors develop three liquid homologous inactivated adjuvant CPV vaccines that were compatible with existing canine vaccines and could be incorporated in current vaccination programmes. On vaccine (Kavak Parvo) contained only the CPV component, the second product (Kavak i-LP) also contained two inactivated leptospiral antigens, and the third vaccine (Kavak i-HLP) contained in addition an inactivated canine hepatitis virus. This paper reports on the studies conducted to test the safety and efficacy of the three products. They were used as such and as diluents for freeze dried vaccines containing live attenuated measles, distemper, and hepatitis viruses. The study was performed in a breeding kennel where all dogs were free from CPV antibodies and the nonvaccinated sentinels remained so for the course of the study. All vaccines proved to be safe in dogs of all ages, including pregnant bitches. The efficacy of the CPV component was studied both by monitoring antibody titres for more than a year and by challenge exposure of some dogs to virulent CPV. The results obtained from these studies prove that the CPV component used in the three vaccines can be incorporated as indicated in the recommended canine vaccination programmes. The observations that the inactivated CPV and hepatitis components do induce an active immunity in pups that are still protected by low levels of maternally derived antibodies against these viruses, make those vaccines very suitable in breeding kennels. Additional studies on a comparative basis are being continued in edemically CPV infected breeding kennels to quantify the significance of these observations in these special conditions.

A longitudinal serological survey of parvovirus infection in dogs

Serum samples collected from dogs routinely presented at a clinic between June 1974 and October 1980 were tested for the presence of haemagglutination inhibition (HI) titres to canine parvovirus. The first positive titre (>1:320) was demonstrated in serum collected in October 1979. The first confirmed clinical case of canine parvovirus enteritis was diagnosed by the authors in July 1979. In addition, between 1st December 1980 and 1st March 1981, serum samples were collected from 106 healthy dogs which were presented for canine parvovirus vaccination for the first time. Twenty-four dogs (approx. 23%) showed HI titres >1:320 indicating probable previous canine parvovirus infection. Therefore approx. 80% of dogs in the clinic area were at risk at that time and vaccination should have protected them from infection.

A Computer Simulation Model for the Control of Rabies in an Urban Area of Colombia

A simulation model is developed describing the transmission of canine rabies within and between 116 spatially distributed barrios (neighborhoods) in Cali, Colombia. The discrete time, dynamic model considers both discrete random variables (incubation and infective periods, appearance and movement of rabid dogs through the city, etc.) and deterministic variables (demographic components of barrio canine populations). Values for the input variables were acquired through field observations, other Colombian sources, and a review of the literature. Various canine vaccination strategies were tested in the model over a ten-year planning horizon for their cost-effectiveness with regard to the prevention of canine rabies. The model is recommended to the Pan American Health Organization to be used as an interactive gaming model to aid health system managers in Cali, Colombia and in other Latin American cities in scheduling the time and locations of vaccination teams in a more cost-effective manner.

Canine vaccination and distemper.

Canine vaccination and distemper.

Canine vaccination and distemper.

Canine vaccination and distemper.

Animal diseases of public health significance.

Excerpt The relation of disease in animals and man has been recognized for thousands of years. The earliest observations were recorded by the Egyptian physicians who administered to the ills of ani...