Bacterial disease outbreak threatens metro Detroit animals
Published: Oct. 27, 2011 EAST LANSING, Mich. — More than 20 cases of the life-threatening bacterial infection leptospirosis have been reported in Detroit-area dogs in the past three weeks, according to Michigan State University’s Diagnostic Center for Population and Animal Health.
Experts at the MSU center, a service unit of the College of Veterinary Medicine, diagnosed the specific strain of the disease, which can cause fatal damage to dogs and can be transmitted to humans.
In most cases, the dogs were not vaccinated against leptospirosis, or they had an uncertain vaccination history. Because this particular type of leptospirosis is associated with contact with rats, stray dogs are typically thought to be at highest risk.
“What is particularly unusual about this outbreak is that the dogs affected are not stray animals, but people’s pets,” said Carole Bolin, director of the Diagnostic Center. “Unfortunately, we expect to see more cases, and this is a very dangerous type of leptospirosis. Many veterinarians have never seen this type in dogs because it was markedly reduced by vaccination.”
Bolin and her team performed diagnostic testing and identified the particular strain of infection as icterohaemorrhagiae, which can cause severe disease in humans and animals. It is commonly carried by rats but also can be transmitted dog-to-dog or dog-to-human. Bolin is aware of nine dogs that died or were euthanized as a result of the disease, but there may be others.
“The Diagnostic Center became involved because of our experience, expertise and our desire to help the public,” Bolin said. “Our diagnosis helped identify this relatively rare strain, and the samples we tested will provide teaching tools for our students and residents so they will recognize this disease in the future.”
Leptospirosis spreads by infected wild and domestic animals. The bacteria (leptospira) that infects these animals can reside in their kidneys, and the host animal may or may not appear ill. They contaminate their environment with living leptospira when they urinate. Pets can become infected by sniffing this urine or by contacting standing water that becomes contaminated by rain and water runoff.
The bacteria spread rapidly through an animal’s blood stream, usually causing fever, depression and vomiting. The bacteria also attack the liver and kidneys, which can lead to organ failure.
“This is a very serious, rapidly progressing type of leptospirosis in dogs,” Bolin said. “Dogs can appear normal one day and be severely ill the next day. People can become infected, so this also is a threat to animal owners, caretakers and veterinarians.”
In the 1980s, Bolin’s mentor Alex Thiermann conducted studies on the high leptospirosis prevalence in the rat and dog population in Detroit. Leptospirosis caused by icterohaemorrhagiae was identified as a cause of human cases and as a common infection in rats and stray dogs. The prevalence of leptospirosis dropped significantly after the conditions predisposing to large rat populations were corrected.
Also, a leptospirosis vaccine was routinely administered to dogs, greatly diminishing the number of cases. As cases of disease in dogs decreased and because of the vaccine’s potential for adverse reactions, vaccine use diminished and it no is longer given to all dogs. However, Bolin said this outbreak demonstrates that leptospirosis remains a significant risk for dogs.
“There is something we can do now to prevent this disease and that is to vaccinate,” she said. “Dog owners need to contact their veterinarian to get more information regarding vaccination.”
MSU’s Diagnostic Center for Population and Animal Health has become one of the country’s premier veterinary diagnostic laboratories, handling more than 220,000 cases involving approximately 1.5 million tests annually.Contact: Kristen Flory, College of Veterinary Medicine, Office: (517) 355-5165, florykri@cvm.msu.edu; Jason Cody, University Relations, Office: (517) 432-0924, Cell: (734) 755-0210, Jason.Cody@ur.msu.edu
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Michigan State University has been working to advance the common good in uncommon ways for more than 150 years. One of the top research universities in the world, MSU focuses its vast resources on creating solutions to some of the world’s most pressing challenges, while providing life-changing opportunities to a diverse and inclusive academic community through more than 200 programs of study in 17 degree-granting colleges.

In addition to working toward eliminating rabies where it already exists, WS also works with States to monitor uninfected areas near the vaccination zones. If a positive case was found, a contingency action
plan may be implemented. Contingency actions often include WS personnel and cooperators’ conducting
enhanced rabies surveillance. WS may also trap raccoons and skunks to vaccinate them against the
disease and then return them to the wild. Oral rabies baits containing vaccine also may be distributed
where the first case or cases originated to create immunity and prevent rabies from spreading.

Distributing the Vaccine The baits manufactured by Merial Inc., consist of either a coated sachet (a  catsup-sized plastic packet coated with fishmeal attractant) or an uncoated sachet encased within a fishmeal bait about the size of a matchbox. The sachet contains the Raboral V-RG® oral rabies vaccine.

Oral rabies vaccine is distributed mostly by air, but some residential or other populated areas may be baited by hand. Fixed-wing aircraft are the most effective means for dispersing large numbers of the ORV baits over rural areas. Hand baiting is used in urban and suburban areas to increase the likelihood of raccoons finding the baits while reducing the chance of people or domestic animals coming into contact with the vaccine.
If you discover a bait, the best action is to leave it where you found it. Do not attempt to remove a bait from the mouth of your pet; doing so may cause you to be bitten. This vaccine cannot cause rabies and is safe if eaten by domestic dogs and cats. It has been tested on more than 60 animal species with no adverse effects. If you come into contact with the pink-liquid vaccine contained within the bait, wash the affected area  thoroughly with soap and water and call USDA’s WS office toll free at 1–866–4USDA–WS (1–866–487–3297) for further instructions and referral.

ORV baits are a sachet—or plastic packet—that contains the rabies vaccine. When a raccoon bites into a bait, the sachet ruptures, allowing the vaccine to make contact in the animal’s mouth and throat. Animals that have contact with an adequate dose of the vaccine develop antibodies against rabies. As the number of vaccinated animals in the population increases, the ability to transmit the disease decreases.

Determining the Effectiveness of the Program
After baits have been distributed and raccoons have had a chance to ingest them, WS works with its cooperators to measure the success of the ORV campaign. Live-traps are set and checked daily. These traps
are affixed with labels in case individuals discover a trapped animal and wish to contact WS. All captured
raccoons are temporarily anesthetized so that blood samples can be taken and a small, single-rooted
premolar tooth may be removed. Once the anesthesia has worn off, the raccoons are released back into the
wild at their capture sites.
All samples are sent to cooperating laboratories such as the rabies laboratory at the Centers for Disease Control and Prevention (CDC) in Atlanta, GA, where the rabies antibody level for each raccoon sample is determined. Tooth samples are sent to laboratories for examination to determine the animal’s age and if their tooth contains a tetracycline biomarker indicating whether one or more baits were ingested. The biomarker causes the formation of a tissue layer in tooth and bone visible under a fluorescent microscope.

The Future
Expertise from a variety of sources, including public health, wildlife, and agricultural agencies, is integral to
the team-centered approach for rabies prevention and control. WS provides a variety of technical and operational services for rabies management, including assistance with effective disease and wildlife population
surveillance, a continuing commitment to the development of additional species-specific oral vaccines, and improved strategies to prevent human exposure to rabies.

Protect Yourself from Rabies
As the cost of living with rabies in the United States exceeds $300 million a year, it is important to educate
the public about how to keep from contracting this disease.
Listed below are helpful hints on how to reduce the possibility of contracting the rabies virus.
• Do not touch or pick up wild animals or stray domestic animals.
• Properly vaccinate all family pets against rabies.
• Report unknown or strangely acting animals to your local animal control officer or, if the animal is wild, to wildlife officials.
• Do not make your yard inviting to wild animals. Remove trash and secure garbage cans. Do not leave pet food outside.
• Keep family pets indoors at night. During the day, do not let them roam.

If You Are Bitten
• Immediately wash the bite with soap and water for five minutes
• Try to capture the animal only if you can do so without receiving additional bites or other injuries.
• Immediately report the bite to your doctor and your local health officer.

Additional Information
For more information, please visit the National Rabies
Management Program’s Web site at www.aphis.usda.
gov/wildlife_damage/rabies/index.html or call 1-8664USDA-WS (1-866-487-3297) to contact your WS State office.

United States Department of Agriculture
Animal and Plant Health Inspection Service
The U.S. Department of Agriculture (USDA) is an equal opportunity provider and employer.

Humans and pets cannot get rabies from contact with the baits, but are asked not to disturb them if  discovered. This vaccine has been shown to be safe in more than 60 different species of animals, including domestic dogs and cats. If contact with vaccination bait occurs, a person should immediately rinse the
affected area with warm water and soap. For information concerning accidental contact with baits, call 1-877-722-6725.

Six agencies are partnering with the U.S. Department of Agriculture’s Wildlife Services for this program, including the state departments of Agriculture and Health, the Pennsylvania Game Commission, Erie County Health Department, Allegheny County Health Departme nt and the Center for Disease Control.
For more information about efforts to reduce rabies in Pennsylvania, contact the Pennsylvania Department of Agriculture at 717-772-2852, or visit www.agriculture.state.pa.us and search for “rabies.”

Media contact: Nicole L. C. Bucher, 717-787-5085

Recommendation for annual revaccination of all dogs with multivalent or combo vaccines assumes that every dog is at significant risk for exposure to every infectious agent in the vaccine, and that each agent in the vaccine will stimulate the same degree of immunity that lasts the same amount of time.1 Today,we know that these assumptions are neither rational nor scientifically justified, but are convenient for the veterinarian and pet owner alike.
Vaccination should not be a regimented, one-fits-all procedure.1 The objective of vaccination is simply to give the right vaccine at the right time to the right individual to protect that individual from an infectious disease. To accomplish this objective, each dog should be evaluated with regard to age, lifestyle, disease prevalence in the community, potential for exposure to infected dogs and environments, and the severity of clinical disease, if any, after infection.2 The benefit of vaccination is questionable if the potential for exposure is limited by lifestyle, the prevalence of disease in the community is low, and the clinical disease is either unapparent or mild.

Vaccination is a medical procedure, and as such, requires individual assessment of each patient. Fortunately, the most common effect of vaccination is stimulation of a protective immune response. Despite the intended benefits, vaccination does carry with it attendant risks. Now, a growing awareness of vaccine-related health problems is motivating veterinarians and pet owners alike to question the benefit of annual revaccination or boosters for adult dogs. The concern, controversy, and confusion centers around the question Are we vaccinating dogs with too many vaccines too often? 2

Vaccine Types
There are three types of vaccines: killed vaccines, modified live vaccines, and recombinant vaccines.1,3
Vaccines that contain killed viruses or bacteria also contain an adjuvant, usually aluminum hydroxide, to nonspecifically boost the immune response to the vaccine. The advantages of killed vaccines include lack of replication in the host, no chance of reversion of the infectious agent to virulence, and safer for use in dogs that are immunosuppressed or in breeding bitches housed in contact with neonates. The disadvantages include a higher incidence of adverse reactions to the killed organisms suspended in adjuvant, formation of lower amounts of antibody that do not remain at protective levels for very long, and requirement for frequent vaccinations to boost the immunity to protective levels. In addition, killed vaccines must be administered by intramuscular or subcutaneous injection. Examples of killed vaccines commonly used in dogs include those for coronavirus, leptospirosis, kennel cough, Lyme disease, giardia, and rabies.
Modified live vaccines (MLV) contain live viruses or bacteria whose virulence has been
modified to allow replication in the host without causing disease. These vaccines simulate natural immune responses in that they stimulate rapid humoral and cell-mediated immunity that is sustained at high levels for long periods of time. Some of these vaccines can be given at the site where the pathogen normally invades the body, such as the nostrils, thus inducing a localized immune response that acts quickly to prevent invasion. Examples of commonly used modified live vaccines in dogs include those for distemper, parvovirus, canine infectious hepatitis, parainfluenza, and kennel cough. Both killed and modified live vaccines can be monovalent or multivalent. Monovalent vaccines contain only one infectious agent, whereas multivalent vaccines contain two or more.
Recombinant vaccines are genetically engineered vaccines created by inserting selected genes from an infectious agent into a nonpathogenic carrier agent that serves as a production factory. The proteins made from the selected genes are those that are critical in stimulating protective immunity to the infectious agent, and thus focus the immune response. The proteins can be harvested after production by the carrier agent and used as a purified protein vaccine, with or without adjuvant. An example of this type of recombinant vaccine is the new one for Lyme disease. Alternatively, a nonpathogenic virus into which the selected genes of the pathogen have been inserted can serve as the actual vaccine. Replication of the nonpathogenic carrier virus in the dog produces the pathogen proteins that induce a protective immune response. An example of this is the new recombinant vaccine for canine distemper.

Duration of Vaccine-Induced Immunity
Vaccine manufacturers in the United States are required by the USDA to conduct efficacy and safety studies for their vaccines prior to licensure.1 The efficacy studies are challenge studies, the gold standard for demonstrating protective immunity provided by a vaccine. In challenge studies, non-vaccinated and vaccinated dogs are exposed to the virulent organism at various times after vaccination to determine the extent and duration of protection against disease. The manufacturer is not required to establish the full duration of immunity for the vaccine, but only to provide documentation of what they claim on the label, hence the recommendation for annual revaccination.1 However, minimum duration of immunity challenge studies are required for all rabies vaccines, and for all new vaccines using antigens that were not in use prior to 1995.1

Vaccines produced by different companies may induce different durations of immunity against the same diseases. Trials to determine the duration of immunity beyond that of one year that would meet USDA guidelines can be cost-prohibitive. However, recent challenge studies performed by independent research groups have demonstrated that the minimum duration of immunity induced by modified live virus vaccines for distemper, parvo, canine infectious hepatitis, and parainfluenza is actually five to seven years, not one year!1 Furthermore, annual revaccination in these challenge studies did not provide any additional benefit in terms of the strength of the humoral immune response elicited, improved resistance to disease, or extension of the duration of immunity.

Thus, based on duration of immunity, annual revaccination of adult dogs is probably not necessary for protection against distemper, parvovirus, canine infectious hepatitis, and parainfluenza.1, 2

Who Should be Vaccinated with What and When?
Puppies less than six months old are more susceptible to the common infectious diseases than adults, and therefore are the primary target population for vaccination.1 In the US, the incidence of clinical disease from distemper, infections hepatitis, and parvovirus in dogs older than one year of age is virtually zero.1
In 2001, the American Veterinary Medical Association Council on Biologic and Therapeutic Agents (COBTA) presented guidelines for vaccination of dogs.2 The guidelines emphasized that there are inadequate data at this time to support a single best vaccination protocol, so veterinarians should perform a risk to benefit analysis for the use of each vaccine in each patient. The guidelines divide currently available vaccines into core and non-core. Core vaccines are selected based on the prevalence of the infectious agent in the environment, the severity of the clinical disease that results from infection, the ease with which the infectious agent is transmitted between animals, and the zoonotic potential. Core vaccines include canine distemper, parvovirus, infectious hepatitis virus, and rabies. Non-core vaccines are those that are useful in situations where the risk of exposure is high and disease can be debilitating. These include vaccines for leptospirosis, parainfluenza, coronavirus, kennel cough, Lyme disease and giardia.

High levels of maternal antibodies acquired from ingestion of colostrums protect puppies from disease for the first six to eight weeks of life. After six to eight weeks of age, a window of susceptibility to infection is created because maternal antibodies are high enough to interfere with the vaccine-induced response, but not high enough to protect the pup from infection and disease.1 This maternal antibody blockade is the most common cause of vaccine failure in puppies. Therefore, immunizations are repeated at timed intervals during the first four to six months of the puppy’s life to insure development of a protective immune response. The pediatric series include the core vaccines for distemper, parvovirus, and infectious canine hepatitis starting with an initial immunization at six to eight weeks of age, followed by boosters every three to four weeks until 16 weeks old. Certain breeds have a higher frequency of individuals that do not develop vaccine-induced antibody titers during the routine pediatric series. These breeds include the Rottweiler, Doberman Pinscher, Labrador Retriever, Alaskan sled dog, Pomeranian, and American Staffordshire Terrier.4 For puppies of these breeds, boosters are recommended every three to four weeks until 24 weeks of age.

The most popular core vaccines are modified live vaccines that contain a combination of distemper virus, canine adenovirus type 2 for protection against infectious hepatitis, parvovirus and parainfluenza virus (DHPP or DA2PP). Contrary to popular belief, combining these viruses into multivalent vaccines does not alter the immune response to each ; no scientific study has shown that one virus suppresses the immune response to the other viruses given at the same time, so it is not necessary to alternate vaccination with each separately.1 Several potentiated monovalent vaccines are available for parvovirus. Potentiated vaccines contain very high titers of parvovirus, and are most effective in overcoming the maternal antibody blockage in young puppies. The original parvovirus, CPV2, has been replaced over the years by two antigenic variants or biotypes called CPV2a and CPV2b. The CPV2b biotype is more prevalent in the US, while the CPV2a is more prevalent in Europe. Most licensed parvovirus vaccines still contain the original CPV2 virus, but the induced immunity is cross protective against both biotypes.1, 5 A recently marketed recombinant vaccine for distemper (Recombitek CDV, Merial) uses the canarypox virus as a vector for a distemper virus gene that codes for a protein associated with protective immune responses.3 The vaccine is effective but the minimum duration of immunity beyond one year has not been established.

The last core vaccine administered during the pediatric series is rabies. The rabies vaccine is the only one that is legally required due to the health threat to humans. Most states require an initial vaccination at 12-16 weeks of age, followed by a booster one year later. State laws vary on revaccination intervals for adult dogs, with intervals ranging from one to three years. Rabies vaccines contain large amounts of killed virus suspended in adjuvant, and have a minimum duration of immunity of one year or three years.

Based on the long duration of immunity for the core vaccines against distemper, canine infectious hepatitis, and parvovirus, Dr. R.D. Schultz at the University of Wisconsin proposed that a more ideal vaccination program would be one in which dogs were revaccinated one year after completion of the pediatric series, then at three-year intervals thereafter.1 However, revision of current protocols for these vaccines should not be done without accurate epidemiological data about the prevalence of each disease in the community, and a careful risk assessment for each dog.

Non-Core Vaccines
Non-core vaccines are recommended only for dogs in situations where the risk of exposure is high and the disease can be debilitating.2 These include vaccines for coronavirus, leptospirosis, parainfluenza, kennel cough, Lyme disease, and giardia. Most non-core vaccines require annual revaccination due to their short duration of immunity. In addition, most of these vaccines contain killed organisms suspended in adjuvant, which increases the risk for vaccine-associated reactions.
Canine coronavirus can cause clinical disease in pups less than six weeks old, but most are protected by maternal antibodies.1 The clinical disease is very mild compared to parvo, and unlike parvo, is confined to the intestinal tract without any systemic involvement. Concurrent infection with coronavirus can contribute to the severity of clinical disease in puppies infected with parvovirus, but vaccination of puppies against parvovirus will prevent disease from both.1
Therefore, it is difficult to rationalize the use of a coronavirus vaccine, but more doses of multivalent vaccines containing killed coronavirus are sold than those without, indicating that most pups and adult dogs are routinely vaccinated anyway. The vaccine, which contains killed virus in adjuvant, may be most useful for brood bitches in kennels where diarrhea is a problem in young pups prior to weaning. Vaccines containing killed coronavirus combined with killed leptospirosis bacteria targeted for use in puppies should not be used due to increased frequency of hypersensitivity reactions.1
Canine leptospirosis is a bacterial infection that causes kidney and liver failure in dogs of all ages. The bacterial species, Leptospira, has several different variants, called serovars, which are antigenically distinct from each other, thus antibodies to one will not protect against infection with other serovars. Vaccines for leptospirosis contain killed bacteria from the L. canicola and L. icterohemorrhagie serovars. The killed bacteria are usually incorporated into multivalent vaccines containing modified live distemper virus, parvovirus, adenovirus, and parainfluenza virus (DHLPP, DA2LPP). The killed bacteria suspended in adjuvant are responsible for many hypersensitivity reactions, particularly in Dachshunds and other small breeds, and only induce a short-lived immunity of six to eight months.1 However, widespread use of multivalent vaccines containing L. canicola and L. icterohemorrhagie for many years has been credited with the reduced prevalence of these two serovars in the canine population. New serovars, such as L. Pomona and L. grippotyphosa have now emerged as the predominant cause of canine leptospirosis, and the old vaccines do not induce protective immunity to these bacteria.1
Recently, Fort Dodge has developed a new killed vaccine that contains L. Pomona and L. grippotyphosa for use in dogs at risk for exposure, but the duration of immunity is still less than 12months.1
Kennel cough, or infectious tracheobronchitis, is an upper respiratory tract disease caused by Bordetella bronchiseptica bacteria alone, or in concert with a variety of viruses such as parainfluenza, distemper, canine adenovirus type 2, and herpesvirus. The intranasal vaccine contains live avirulent B. bronchiseptica combined with modified live parainfluenza virus. This vaccine rapidly stimulates mucosal and cell-mediated immunity in the upper respiratory tract where the pathogens enter the body, so that vaccination three to five days prior to anticipated exposure provides protection. The intranasal vaccine can also be given to pups after three weeks of age, and is not subject to the maternal antibody blockade. However, replication of the attenuated bacteria and virus in the upper respiratory tract can cause mild clinical signs that resolve in a few days. The parenteral vaccines given by injection contain killed B. bronchiseptica, and thus require boosters two to four weeks apart to generate protective levels of immunity. These killed vaccines induce systemic immune responses that contribute to protection of the respiratory tract without inducing a mild clinical disease like the modified live vaccine, but do cause more vaccine-associated hypersensitivity reactions.

Parenteral vaccines are safe to use in breeding bitches, but are subject to maternal antibody blockade when given to puppies. The duration of immunity for both the intranasal and parenteral vaccines is probably less than 12 months.1 It is generally thought that stimulation of local immunity in the respiratory tract with an intranasal vaccine is superior to use of parenteral vaccines. Others have proposed that protocols incorporating both types of vaccines are superior to either vaccine alone. A recent study6 found that administration of both the intranasal and parenteral vaccine once each in sequence afforded better protection and less severe clinical signs from B. bronchiseptica challenge than either vaccine alone.
Lyme disease is caused by Borrelia burgdorferi bacteria transmitted by tick bites. The vast majority (99 percent) of cases are in the northeastern, middle Atlantic and upper Midwester n states. Vaccination is recommended for dogs in these endemic areas, but not for dogs in areas of low prevalence, such as the southeast.1 The Lyme vaccine contains killed bacteria suspended in adjuvant, and has produced postvaccinal lameness in dogs. In addition, the vaccine contains limited strains of the bacteria and may not induce cross protective immunity to other strains that cause disease. A new recombinant vaccine licensed for use in dogs contains purified bacterial out surface protein A (OspA) instead of whole bacteria, does not have an adjuvant, and challenge studies have shown a minimum duration of immunity of one year.3
Giardia is a protozoan that infects the gastrointestinal tract of birds and mammals worldwide, and causes explosive diarrhea, gas, and pruritic skin lesions in dogs. The infection responds to medical therapy, but reinfection rates are high because the infectious cysts shed in fecal material persist on the dog and in the environment. There is a new killed vaccine (GiardiaVax, Fort Dodge) licensed for use in dogs and pups older than six weeks that contains inactivated giardia trophozoites. Challenge studies have shown that the vaccine stimulated a strong antibody response within three weeks, and vaccinated dogs were less severely affected clinically and shed cysts for a shorter time compared to non-vaccinated dogs1. The decreased shedding of cysts was maintained for up to one year. In a clinical trial supported by the manufacture7, six pet dogs with chronic giardia infections for months to years received two doses of the vaccine given three weeks apart, which eliminated clinical signs and shedding of cysts with two to eight weeks. However, in a recent independent study8 in which digs infected with giardia were treated medically with or without the vaccine, medical treatment alone was effective without the vaccine, as long as the dogs were bathed and put in a different environment. The vaccine did not prevent recurrence of infection in dogs that were not bathed and moved to a different environment.

Assessment of Immune Status by Antibody Titers
One method to assess the adequacy of humoral immunity induced by vaccination is measurement of antibody titers to the infectious agent vaccinated against. The vaccine-induce antibody titer is compared to a standard titer associated with prevention of infection. Antibody titers are increasingly recommended as an objective method for determining the need for revaccination. However, antibody titers do not necessarily correspond to protection against disease.1, 2 A high antibody titer does not guarantee immune protection, and a low or negative antibody titer does not mean loss of immunity and susceptibility to infection. Certain breeds have higher numbers of individuals that do not develop antibody titers after vaccinations. These breeds include the Rottweiler, Doberman Pinscher, Labrador Retriever, Alaskan sled dog, Pomeranian, and American Staffordshire Terrier.4 Yet, dogs in these breeds with no or low antibody titers remain healthy, presumably because of vaccine stimulation of other important immune system compartments such as cell-mediated immunity, mucosal immunity, and immune memory cells, all of which cannot be accurately or practically measured at this time. Unfortunately, there are no standardized tests for measuring antibody titers with reliable interpretations, so that submission of a serum sample to three different labs most likely would yield three different results with three different interpretations.2

In a recent study4, serum antibody titers to distemper and parvovirus were measured in 1,441 dogs of various ages and breeds located across the US and Canada. In this population, more than 95 percent had adequate titers to distemper and parvo. For the 468 dogs with known vaccination histories, the interval of time after the last vaccination was one to two years for the majority (60 percent), two to seven years for 30 percent, and less than one year for ten percent. Based on these results, the authors concluded that annual revaccination of adult dogs may not be necessary, and that an acceptable alternative approach is antibody titer screening to determine the need for vaccination on an individual basis. An alternate vaccination protocol has also been proposed for puppies from families with known genetic predisposition to adverse vaccine reactions or immune-mediated diseases.9 This protocol suggests using only monovalent vaccines for distemper and parvovirus with alternating administration every three to four weeks until the puppy has received a total of three doses of each vaccine. The vaccines are boosted at one year of age, again using monovalent vaccines given at least two weeks apart, followed by measurement of antibody titers to determine future need for revaccination.

Adverse Vaccine Reactions
Just as no vaccine is 100 percent effective in preventing disease, no vaccine is 100 percent free from causing an adverse reaction. An adverse event is defined as any undesirable consequence, including illness or a reaction, after the use of a vaccine, whether or not a cause-and-effect relationship can be established.2 The most commonly recognized adverse reactions are the nonspecific reactions of immune system stimulation, including fever, anorexia, and stiffness for 24-36 hours after vaccination.10 Another common systemic reaction, most frequently reported with killed vaccines, is immediate hypersensitivity of anaphylaxis, indicated by urticaria (hives) and pruritis of the face and ears followed by vomiting and/or diarrhea in some dogs.10 These signs can occur immediately after vaccination or several hours later. Local reactions to vaccines with adjuvants include swelling, pain, lumps, and hair loss at the vaccine site. Other reactions include abortions and birth defects due to vaccination of pregnant dogs, and illness in neonates exposed to dogs recently vaccinated with modified live vaccines that are shedding the vaccine viruses into the environment.

For most currently available vaccines, the benefits derived far outweigh the risks for an adverse event when vaccination is performed in accordance with published standards.10 With the technology available today, there is no way to accurately predict what vaccine will pose a threat to which dog and when.
Manufacturers of human vaccines are required to list on the vaccine label the type and frequency of adverse events that occurred during safety trials.10 There are approximately 12,000 reports of adverse events annually for human vaccines, all of which must be forwarded to the FDA, the federal agency that regulates drugs and vaccines for humans.10 In contrast, animal vaccine manufacturers are neither required to list possible adverse reactions on vaccine labels, nor keep records of adverse events reported directly to them, nor forward reports to the USDA, the federal agency that regulates drugs and vaccines for animals.10 There are approximately 10,000 reports of adverse events associated with animal vaccines annually in the US, but the vast majority of these are communicated directly to the manufacturers.10 However, veterinarians and pet owners can report concerns directly to the USDA or to the Veterinary Practitioners Reporting Program, which is a volunteer watchdog organization that forwards reports of adverse reactions to the USDA, vaccine manufacturer, and the AVMA in an effort to protect animal health.
One of the best-developed surveillance schemes in the world for monitoring adverse reactions to veterinary vaccines is in the United Kingdom. In contrast to the US, vaccine manufacturers in the UK are legally required to record reports of adverse reactions and submit the reports to a regulatory agency.11 The Veterinary Products Committee, an independent group that gives advice on the safety, quality, and efficacy of veterinary vaccines to the regulatory agency, recently published a report on vaccine-associated adverse events in the UK.11 The overall annual incidence of adverse events in dogs from 1995 – 1999 was less than 0.1 percent per 10,000 doses of vaccines sold, which is similar to that reported in Australia. Toy breeds and puppies less than six months old had the highest incidence of the five-year reporting period. Anaphylaxix reactions were the most common type reported. The group concluded that there are insufficient scientific data to warrant changing revaccination intervals from that already approved by the regulatory agencies, and that the very low incidence of adverse reactions sdtronly supports continued vaccination. However, the group strongly emphasized that dogs should be individually assessed with regard to the need for each vaccine as well as the frequency of administration.

Immune-Mediated Diseases and Vaccinosis
There is increasing evidence suggesting that vaccination, particularly overvaccination, is associated with development of immune-mediated disorders and chronic diseases, or vaccinosis, in individuals that are genetically predisposed. Certain breeds appear more genetically predisposed to developing adverse reactions and immune-mediated diseases following vaccination, including the Old English Sheepdog, Akita, American Cocker Spaniel, Standard Poodle, Scottish Terrier, Shetland Sheepdog, Shih Tzu, Vizsla, Weimaraner, Irish Setter, Doberman Pinscher and Dachshund.9 There are two published studies12, 13 that linked vaccination and development of immune-mediated hemolytic anemia. More recent reports9, 14 have suggested vaccine-induced development of Hypertrophic Osteodystrophy in Weimaraner puppies that were genetically predisposed to the disease. Other reports linking vaccination to development of joint diseases, neurological diseases, and thyroid disease are largely anecdotal, and await rigorous scientific validation. To date, there are no controlled scientific studies that prove a cause and effect relationship between vaccination and development of immune-mediated diseases or chronic diseases.10, 11
Due to concern about vaccination overload of the immune system with development of autoimmune diseases and vaccinosis, there has been a proliferation of anti-vaccination websites offering alternatives to conventional vaccinations. One of the alternatives is nosodes which are products prepared from infected tissues or discharges given orally.2 General recommendations for use of nosodes include administration orally for three days the first week, then once weekly for three weeks, then once monthly for six months, then every six months thereafter. The dose is three drops for small dogs and six drops for large dogs. The nosode does not cause disease because of homeopathic dilution, where the product is diluted enough that the amount of infectious material remaining is too little to cause disease. There has been only one controlled study on the efficacy of nosodes for protection against disease. This study2 examined a nosode for parvovirus and found that 100 percent of the non-vaccinated as well as vaccinated puppies became infected when challenged with the virus.

Conclusion
Are we vaccinating dogs with too many vaccines too often? Probably. No doubt, there will be changes in the who, what, when and how for canine vaccinations. In general, canine vaccines are effective and safe, with benefits that far outweigh the risks. However, more rigorous controlled studies are needed on vaccine efficacy, duration of immunity, and safety to point out a scientifically sound direction for change. Change is hard, and human nature resists change unless there is compelling evidence to do so. It is important to remember that the overall goal of vaccination is protection of the population as a whole, which can be achieved by vaccinating more dogs, but vaccinating each dog less. To date, the best protocol for vaccination is individual assessment of every dog with regard to age, health status, risk of exposure to the infectious agent, prevalence of the infectious agent in the community, and severity of illness caused by the infectious agent.

Selected References
1. Greene CE, Schultz RD, Ford RB. Canine Vaccination. In: North American Veterinary
Clinics 2001. Ford RB, ed. 31(3): 473-492.
2. Ford RB. Vaccines and vaccination: The strategic issues. In: North American Veterinary
Clinics 2001. Ford RB, ed. 31(3): 439-453.
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immunotherapeutic agent in dogs. Can Vet J 2001; 42:865-868.
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Dog Owners and Breeders Symposium
July 27, 2002
University of Florida
College of Veterinary Medicine

Puppy Vaccination Schedule

Adult dog vaccination schedule

for dogs acquired at over 16 wks.

*It is important to use a modified live virus (MLV) or the r- (recombinant) virus if possible, to decrease the risk of injection site fibrosarcoma, a rare but complicating reaction.

For a discussion of the canine immune system and vaccination interaction see  http://www.labbies.com/immun.htm<

“It’s a relatively new disease,” Schultz says. “I estimate that greater than 90 percent of the canine population is immunologically naive.” Because most dogs have never been exposed, they have no natural protection against the disease, making the new vaccine a valuable tool.

Another major consideration is that canine influenza, just like the human flu, weakens the dog’s immune system. “The virus will often set up the opportunity for a secondary disease,” Schultz says, explaining that it is common for dogs to have bacteria already in their system when they are infected with CIV. “Alone, those organisms would rarely cause much of a problem,” he adds. “But the combination can be deadly.”

Fortunately, Schultz’s new work – which depended on research using animal models – shows positive results: The CIV vaccine significantly reduced the severity of the disease even with the combination of CIV and a Streptococcus equi zooepidemicus bacterial infection. In future studies, Schultz hopes his lab will be able to show that the same is true of other bacterial infections common to dogs. “We want to demonstrate that the vaccine protects against any co-infections that might occur,” he says.

“The real issue now among the dog owning public is, ‘Do we need to get our dog vaccinated?’” Schultz says.

He recommends the vaccine for dogs at high risk of infection – those that stay in close quarters with other dogs, like at training classes, shows or doggy daycare.

“It’s very much a proximity issue,” he adds. Open-air spaces like dog parks, however, carry a much lower risk.

Because the vaccine is made from a killed form of the virus, it requires two doses spaced two weeks apart and is effective one week after the second dose. This means that pet owners need to think ahead and start vaccinating at least three weeks before they think their dog will face exposure. According to Schultz, this is the major hurdle of the vaccine.

“Where they know the animal has the highest risk, the vaccine can’t work,” says Schultz.

For example, animal shelters taking in new dogs simply can’t wait three weeks for the dog to reach immunity. That’s why Schultz hopes the new vaccine can build immunity of the dog population as a whole.

“Even if you have 20 to 30 percent of dogs vaccinated, that would make a difference,” Schultz says. “It’s a group thing.”

Although this outbreak is milder than originally feared and is responding well to the vaccine, Schultz remains cautious.

“It only takes one of those outbreaks, and then people really start to think,” he says. “It’s not ‘mild’ for the dog that dies.”

Source:
University of Wisconsin-Madison

Article URL: http://www.medicalnewstoday.com/articles/194171.php

Most dogs have no immunity to canine influenza because it is a novel pathogen and, therefore, the infection can spread quickly through animal shelters, adoption groups, pet stores, boarding kennels, veterinary clinics and any location where dogs congregate. According to the U.S. Centers for Disease Control and Prevention (CDC), there is no evidence of transmission of the virus from dogs to people.

According to Terri Wasmoen, Ph.D., an immunologist and senior director of Biological Research for Intervet/Schering-Plough Animal Health, dog owners might not realize their pets are sick enough to need medical care until the dogs begin coughing, which occurs several days or more after the dog contracts CIV. The onset of coughing is a sign that the dog is vulnerable to pneumonia. “Preventing a viral infection that can make dogs susceptible to a complex of canine respiratory pathogens, commonly known as kennel cough syndrome, further strengthens the case for vaccination,” she said.

“Canine influenza is a highly contagious respiratory infection that has a significant impact on dogs housed in shelters, kennels and communal facilities,” said Cynda Crawford, D.V.M., Ph.D., University of Florida, Clinical Assistant Professor of Shelter Medicine. “The availability of a vaccine can help prevent the medical, financial and emotional costs associated with this new virus.”

Canine Influenza Vaccine, H3N8 has been demonstrated to reduce the incidence and severity of lung lesions, as well as the duration of coughing and viral shedding. The vaccine, made from inactivated virus, is intended as an aid in the control of disease associated with canine influenza virus infection, a type A, subtype H3N8. It is administered by subcutaneous injection in two doses, two to four weeks apart. It may be given to dogs six weeks of age or older and can be given annually as a component of existing respiratory disease vaccine protocols to ensure more comprehensive protection.

APHIS ISSUES CONDITIONAL LICENSE FOR CANINE INFLUENZA VIRUS VACCINE

WASHINGTON, June 23, 2009–The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) today announced that it has issued a conditional license to Intervet/Schering-Plough Animal Health for a canine influenza virus (CIV) vaccine.

APHIS, through its Center for Veterinary Biologics (CVB), granted the conditional license following the acceptance of data supporting product purity, safety and a reasonable expectation of efficacy. The safety data included the results of studies that evaluated the product under normal conditions, including field safety trials of the size and scope required for full licensure.

Dr. Cynda Crawford, a University of Florida College of Veterinary Medicine infectious-disease specialist who was instrumental in identifying the virus in racing greyhounds in 2004, is hearing from veterinarians who seek advice.

Crawford says: Unless your dog is regularly in close contact with other dogs, especially if you live in what she calls a “hot zone” (see below) where there’s an outbreak or where there have been multiple past outbreaks — the vaccination probably isn’t necessary. Dogs with weakened health or those travelling to hot zones are special cases that require discussion with a veterinarian.

The vast majority of dogs that contract CIV recover in one to three weeks (though up to 5% die, usually of pneumonia that develops secondary to the flu — generally older dogs, puppies and dogs with already compromised immune systems). And some will develop severe versions of the normal coughing, fever, runny-nose, loss-of-appetite symptoms. Some will require what vets call “supportive” help to keep sufficiently hydrated and fevers in check and sometimes antibiotics to battle pneumonia.

The American Veterinary Medical Association is not recommending vaccinating all dogs. But dogs that receive the Bordetella vaccine, the association says, should be considered strong candidates for flu vaccination because they’ve been determined to be at risk for the much-less-serious kennel cough through regular contact with many dogs, and that puts them at higher risk for CIV.

Hot Zones: some areas which have experienced protracted or repeated outbreaks. Those, which expert Cynda Crawford calls hot zones or hot spots, are:

- South Florida (which is in a quiet phase right now)
- Colorado Springs-Denver-Cheyenne, Wyo., corridor
- Philadelphia to eastern parts of New York and New Jersey

The AVMA says two additional spots Pittsburgh and surrounding environs and the Lexington, Ky., area “may be emerging as endemic” areas, meaning the virus seems to be well-established and showing up in relatively higher numbers.

Sources: Schering-Plough Animal Health, APHIS