Evaluation of inactivated infectious coryza vaccines in chickens challenged by serovar B strains ofHaemophilus paragallinarum

Abstract

SUMMARYFour monovalent experimental vaccines (VI, V2, V3 and V7) containing an Argentinean serovar B strain (H8) of Haemophilus paragallinarum and three different commercial vaccines, either bivalent (V4 and V5) containing serovars A and C, or trivalent (V6) containing serovars A, B and C were administered by subcutaneous or intramuscular routes as a single or double dose (at 3-week intervals) to chickens of between 6 and 10 weeks. Three to 7 weeks after the last vaccination, vaccinated and non-vaccinated chickens were challenged by intrasinus inoculation with Argentinean serovar B strains of H. paragallinarum. When the vaccinated chickens were exposed to a severe challenge with the vaccinal strain (H8) some experimental vaccines protected, whereas all commercial vaccines failed to protect. The experimental vaccines manufactured in broth (V2, V3 and V7) protected more effectively than the vaccine produced in chicken embryos (VI). Failure of the commercial trivalent vaccine V6 to protect may be related to the method of manufacture. Vaccine V7 protected against challenge from either the vaccinal strain (H8) or three Argentinean serovar B strains (H6, Hll and HI2). These results confirm the necessity of including serovar B regional strains in the formulation of local vaccines.

Naturally Occurring β-Nicotinamide Adenine Dinucleotide–IndependentAvibacterium paragallinarumIsolate in Peru

“…Nevertheless, Bragg et al (9,10) reported a correlation between the increased incidence of NAD-I isolates and vaccine failure in South Africa, suggesting that only partial cross-protection is given by the serovars included in the vaccine; this finding has also been supported by other authors (7,17,26). However, a report from South Africa signaled that under controlled conditions, the commercial trivalent vaccine protected against NAD-I field isolates (18).…”

The vaccination-challenge trial: the gold standard test to evaluate the protective efficacy of infectious coryza vaccines

“…As all controls were fully susceptible to challenge and as no antibodies to infectious coryza were detected in any chicken prior to vaccination, there is good evidence that the chickens used in this work were fully susceptible to infectious coryza. Our use of commercial chickens is a practice that has been adopted by other infectious coryza vaccine researchers (Terzolo et al, 1997;Jacobs et al, 2003;Bragg, 2004;Soriano et al, 2004).…”

Preparation and use of autogenous vaccine from Avibacterium paragallinarum (strain Tan 1-05) in layer chickens

“…Commercial vaccines for IC which are produced from standard internationally recognized strains of inactivated A. paragallinarum are widely used around the world (Blackall 1999). Furthermore, Blackall (1999) reported that studies conducted in South Africa (Bragg et al 1996) and Argentina (Terzolo et al 1997) have suggested that such international vaccines are not protective against the local variants of A. paragallinarum. Therefore, there is a need to produce vaccines from local strains.…”