HOT TOPICS

1. VS-FELINE CALICIVIRUS (Virulent Systemic Feline Calicivirus)
(Added: January 13, 2008)

2. Canine Bordetella bronchiseptica VACCINES
(Added: January 13, 2008)

3. RECOMBINANT CANINE DISTEMPER
(Added: January 13, 2008)

4. Feline VACCINE ASSOCIATED SARCOMA
(Added: January 13, 2008)

5. Canine SKIN REACTIONS ASSOCIATED WITH VACCINATION
(Added: January 13, 2008)

6. BONE LESIONS ATTRIBUTED to POST-VACCINATION ADVERSE EVENTS
(Added: January 13, 2008)

1. VS-FELINE CALICIVIRUS (Virulent Systemic 'Feline' Calicivirus)

Released in February 2007 (Fort Dodge Animal Health), this killed virus vaccine is sold as a killed, adjuvanted vaccine in four separate products, each of which contains their original calicivirus strain. Several questions about disease risk and vaccine use have surfaced subsequent to vaccine marketing.

FACTS TO CONSIDER…
- infections are severe (mortality = 30% to 50%), but rare. 8 outbreaks have been documented in the US and UK over the past 10 years. There is no evidence to suggest the incidence has recently increased in the US or the UK.
- the VS Calicivirus strain in the vaccine is the same virus strain used in the manufacturer’s vaccine challenge studies (homologous challenge). There are no studies showing vaccine efficacy in a (naturally occurring or experimental) heterologous challenge.
- this vaccine is adjuvanted.
- at this writing, technical data from the manufacturer on the vaccine has not been released.
- until independent studies are published regarding vaccine efficacy, veterinarians should use discretion in deciding whether or not to administer this vaccine. Cats considered to be at risk appear to be shelter/rescue cats and domestic pet cats exposed to these high risk groups.
- the vaccine is NOT generally recommended for routine use in household pet kittens or cats.

TOP

2. Canine Bordetella bronchiseptica VACCINES

A summary of the most recent facts on the INTRANASAL vs INJECTABLE vaccines follows:

  1. There are currently 2 types of vaccines:
    1. ◊ only one vaccine (Bronchicine, Pfizer) is for parenteral administration.
    2. ◊ Various intranasal products are available that contain:
      • · Bordetella bronchiseptica + parainfluenza virus + adenovirus-2, or,
      • · Bordetella bronchiseptica + parainfluenza virus only (recommended by the AAHA Canine Vaccine Guidelines)
  2. Like most bacterins, BOTH vaccine types lessen the severity of disease following exposure; neither vaccine is believed to prevent infection.
  3. Following challenge, the intranasal vaccine prevented bacterial shedding; the injectable vaccine did not. Implication in kennels and shelters: dogs vaccinated by the intranasal route minimize the risk of bacterial transmission to other dogs at risk in the same facility.
  4. ALL intranasal vaccines on the market include MLV parainfluenza virus vaccine…a preferred route of administration.
  5. Initial Vaccination: ONE dose for intranasal vaccines-onset of immunity is 3 to 5 days post vaccination; TWO doses, 2 to 4 weeks apart, are required-onset of immunity may be several days following the second dose.
  6. Booster Vaccination: ONE dose of either vaccine.
    There appears to be NO contraindication to switching vaccine types. Onset of immunity in previously vaccinated dogs is not known. (it’s probably within days for either vaccine type)

TOP

3. RECOMBINANT CANINE DISTEMPER

- Duration of Protective Immunity: challenge studies performed at U of Wisconsin have shown efficacy of the recombinant canine distemper vaccine (Merial) to be comparable to that of any Modified Live Virus (MLV) vaccine. The Duration of Protective Immunity, based on challenge studies, exceeds 3 years.
- Maternal Antibody is the single most significant factor in preventing immunization of puppies vaccinated with a MLV distemper vaccine. However, the recombinant distemper vaccine (Merial) was able to induce protective immunity in 8 week old puppies despite the presence of maternal antibody. Reason: maternal antibody against canine distemper virus does not recognize the virus vector (canarypox) used in the recombinant vaccine.
- Some authors have recommended use of the recombinant canine distemper vaccine (RECOMBITEK Canine Distemper, Merial) in Weimaraners due to the possible risk of vaccine-induced osteopathy (HOD) in puppies. See comments below: #6 Bone Lesions.
- The recombinant canine distemper vaccine (RECOMBITEK Canine Distemper, Merial) is recommended to be administered as early as 3 weeks of age in puppies deemed to be at high risk of exposure to canine distemper virus. (see the AAHA Canine Vaccine Guidelines)

TOP

4. Feline VACCINE ASSOCIATED SARCOMA

Adverse reactions subsequent to vaccine administration, although uncommon, are known to occur in both dogs and cats. Reactions can range from mild to severe (fatal) and are localized or systemic. The actual prevalence and types of injury, however, have not been established. Feline vaccine associated sarcoma is the most serious adverse reaction that has been reported (see updates below).


Veterinarians are encouraged to report adverse vaccine events directly to the manufacturer. However, data generated by these reports are not available to practitioners; there is no national database of adverse vaccine reactions available to veterinarians.
- Feline vaccine associated sarcoma is the most widely documented vaccine adverse event, generally associated with adjuvanted feline leukemia and rabies vaccines. The true prevalence is unknown.
A paper (U of California-Davis) recently presented at the 2007 Veterinary Cancer Society Conference assessed changes in injection site sarcomas in cats from 1990 through 2006.
Conclusion: Tumors are occurring with increasing frequency in difficult surgical sites such as the lateral abdomen. Also, there has been a shift in the sarcoma site from the cranial to the caudal half of the body...which corresponds with vaccination site recommendations of the AVMA’s Vaccine-Associated Feline Sarcoma Task Force.

TOP

5. Canine SKIN REACTIONS ASSOCIATED WITH VACCINATION:

- Dermatologists throughout the US have attributed single and multifocal skin lesions, characterized as ischemic vasculitis, to recent (1 to 3 months) vaccine administration. Although no known deaths have occurred, reactions can be painful and may require expensive treatment.
Lesions seem to develop from 1 to 3 months post-vaccination. Solitary lesions may occur at the injection site (hair loss and change in hair color are reported). Multifocal lesions can affect the skin of the ear tips (with associated necrosis), eyelids, nasal planum, tail, footpads, and occasionally the trunk. Poodles and other dogs under 25 pounds may be over represented.
Killed rabies vaccine (particularly RabVac-3, Fort Dodge Animal Health) is most often implicated in anecdotal reports from veterinarians.

Focal post-vaccination skin lesion in a young maltese Focal post-vaccination skin lesion in a young Maltese. Lesion is non-painful and characterized by a change in hair and skin color at the injection site.


Multifocal lesions Multifocal lesions on the ear-tip of a Chihuahua. Both ear-tips were affected.

TREATMENT: most clinicians/dermatologists recommend against using corticosteroids (may promote coagulation) in the management of these lesions. The following drugs have been used in combination:
- Pentoxyphylline (Trental): 15 mg/kg, PO, q12h (duration is 10 days to 3 weeks as needed to manage the cutaneous lesions).
- Oral Antimicrobials: example: cephalexin, marbofloxacin.
- Vitamin E: 400 IU, PO, q12h, as needed.
- Analgesics: buprenorphine, 0.005 to 0.02 mg/kg, SC, q6-12h as needed to control pain.

TOP

6. BONE LESIONS ATTRIBUTED to POST-VACCINATION ADVERSE EVENTS

Over the past 2 years, a few papers have implicated Modified-Live Virus Canine Distemper Vaccine in causing bone lesions in puppies. Presumably, this is attributed to replication of the modified-live virus in bone. Hypertrophic Osteodystrophy (HOD), particularly in Weimaraners, and Craniomandibular Osteopathy are cited.

It has been suggested that use of the Recombinant Canine Distemper Vaccine (Recombitek Canine Distemper, Merial) would be indicated in breeds that may be at risk for developing these orthopedic disorders.

TOP