The Current Leptospirosis Vaccine
Recent serological studies on wildlife and domestic dogs suggests that L. grippotyphosa and L. pomona have replaced L. icterohaemorrhagiae and L. canicola as the prevalent serovars responsible for Leptospirosis in the United States today. As such, current commercial vaccines, which protect against the formerly prevalent serovars, would not be effective at providing immunity against Leptospirosis caused by L. grippotyphosa and L. pomona. For this reason, there has been some conjecture that current commercial vaccines should be considered obsolete for protecting against Leptospirosis. There are several factors that should be considered prior to drawing this conclusion. First, Leptospirosis vaccines, as mentioned above, protect against clinical disease but do not prevent subclinical infection to a "carrier" state. That is, a dog that is annually vaccinated may harbor infectious organisms of L. icterohaemorrhagiae or L. canicola which will pose a risk of contagion to dogs that are not vaccinated or in which vaccination for these serovars has been discontinued. Without serological testing, low clinical incidence of these formerly prevalent serovars may be a result of the currently large population of vaccinated dogs. If this is the case, discontinuing administration of the current Leptospirosis vaccine may result in a resurgence of clinical disease. Furthermore, it is important to note that samples from these studies are not necessarily representative of all regions of the US.
When all the facts are considered, these findings do not necessarily suggest that L. icterohaemorrhagiae and L. canicola no longer pose a threat to dogs. Rather, this information should be taken into consideration when determining potential risk of infection in dogs that may be candidates for side effects associated with vaccine-reaction. Leptospirosis-containing vaccines are associated with a higher risk for side effects, particularly, anaphylactic reactions (see Canine Anaphylaxis). Taken together, benefits of vaccinating dogs, who live in areas where icterohaemorrhagiae and canicola incidence is low and who may have a higher predisposition for vaccine side effects with current Leptospirosis inoculants (see Vaccines, Infectious Diseases and the Canine Immune System), may not outweigh risks of vaccine reaction.
New Leptospirosis Vaccine Immunizes Against L. grippotyphosa and L. pomona
Fort Dodge now offers the Duramune Leptospirosis vaccine that immunizes against L. grippotyphosa and L. pomona serovars as well as L. icterohaemorrhagiae and L. canicola . This vaccine has been formulated through the new subunit technology that uses only the antigen component of the organism (that will produce an immune response) instead of the entire organism. As such, subunit vaccines greatly reduce vaccine side-effects that occur with higher incidence with bacterin-based vaccines while providing durable protection from the disease.
