Groups of one-day-old broiler chicks were vaccinated via the oculo-nasal route with different live infectious bronchitis virus (IBV) vaccines: Massachusetts (Mass), 793B, D274 or Arkansas (Ark). Clinical signs and gross lesions were evaluated. Five chicks from each group were humanely killed at intervals and their tracheas collected for ciliary activity assessment and for the detection of CD4+, CD8+ and IgA-bearing B cells by immunohistochemistry (IHC). Blood samples were collected at intervals for the detection of anti-IBV antibodies. At 21 days post-vaccination (dpv), protection conferred by different vaccination regimes against virulent M41, QX and 793B was assessed. All vaccination programmes were able to induce high levels of CD4+, CD8+ and IgA-bearing B cells in the trachea. Significantly higher levels of CD4+ and CD8+ expression were observed in the Mass2 + 793B2-vaccinated group compared to the other groups (subscripts indicate different manufacturers). Protection studies showed that the group of chicks vaccinated with Mass2 + 793B2 produced 92% ciliary protection against QX challenge; compared to 53%, 68% and 73% ciliary protection against the same challenge virus by Mass1 + D274, Mass1 + 793B1 and Mass3 + Ark, respectively. All vaccination programmes produced more than 85% ciliary protection against M41 and 793B challenges. It appears that the variable levels of protection provided by different heterologous live IBV vaccinations are dependent on the levels of local tracheal immunity induced by the respective vaccine combination. The Mass2 + 793B2 group showed the worst clinical signs, higher mortality and severe lesions following vaccination, but had the highest tracheal immune responses and demonstrated the best protection against all three challenge viruses.
A survey was conducted into respiratory infectious diseases of poultry on a chicken breeder farm run by the Ethiopian Institute of Agricultural Research (EIAR), located in Debre Zeit, Ethiopia. Oropharyngeal swabs were collected from 117 randomly selected birds, and blood was taken from a subset of 73 of these birds. A combination of serological and molecular methods was used for detection of pathogens. For the first time in Ethiopia, we report the detection of variant infectious bronchitis virus (793B genotype), avian metapneumovirus subtype B and Mycoplasma synoviae in poultry. Mycoplasma gallisepticum was also found to be present; however, infectious laryngotracheitis virus was not detected by PCR. Newcastle disease virus (NDV) was not detected by PCR, but variable levels of anti-NDV HI antibody titres shows possible exposure to virulent strains or poor vaccine take, or both. For the burgeoning-intensive industry in Ethiopia, this study highlights several circulating infectious respiratory pathogens that can impact on poultry welfare and productivity.
Herpes simplex virus type 2 (HSV2) is the most common causative agent of genital herpes, with infection rates as high as 1 in 6 adults. The present studies were done to evaluate the efficacy of a liposomal HSV2 gD1-306 vaccine (L-gD1-306-HD) in an acute murine HSV2 infection model of intravaginal (female) or intrarectal (male or female) challenge. Two doses of L-gD1-306-HD containing 60μg gD1-306-HD and 15μg monophosphoryl lipid A (MPL) per dose provided protection against HSV2 intravaginal challenge (86-100% survival, P≤0.0003 vs control liposomes; P=0.06 vs L-gD1-306-HD without MPL). Both male and female mice (BALB/c and C57BL/6) immunized with L-gD1-306-HD/MPL were significantly protected against HSV2 intrarectal challenge, with higher survival rates compared to controls (71-100%, P≤0.007). L-gD1-306-HD/MPL also provided increased survival when compared to a liposomal peptide vaccine, L-gD264-285-HD/MPL (male BALB/c, P≤0.001; female BALB/c and male C57BL/6, P=0.06). Mice given L-gD1-306-HD/MPL also had minimal disease signs, reduced viral burden in their spinal cords and elevated neutralizing antibody titers in the females. The vaccine also stimulated gD1-306-HD specific splenocytes of both male and female mice with significantly elevated levels of IFN-γ compared to IL-4 (P≤0.01) indicating that there was an enhanced Th1 response. These results provide the first evidence that the L-gD1-306–HD vaccine can protect both male and female mice against intrarectal HSV2 challenge.
An investigation was undertaken of the extent of genetic variation occurring within infectious bronchitis virus (IBV) vaccine strains following vaccination of day-old broiler chicks. Chicks were divided into seven groups, with two groups receiving single Massachusetts (Mass) vaccinations while the other four were inoculated with combinations of different IBV serotypes; Mass, 793B, D274 and Arkansas (Ark). The remaining group was maintained as an unvaccinated control. Following vaccination, swabs and tissues collected at intervals were pooled and RNA was extracted for detection of IBV by reverse transcription polymerase chain reaction. Positive amplicons were sequenced for the part-S1 gene and compared to the original vaccine strain sequences. Single nucleotide polymorphisms, amino acid variations and hydrophobicity changes were identified and recorded for each sampling point. A total of 106 single nucleotide polymorphisms were detected within 28 isolates. The average single nucleotide polymorphism counts of swab isolates were greater than those found in tissue samples. This translated into 64 amino acid changes; however only six resulted in a change to the hydrophobicity properties. All hydrophobic alterations occurred within swab isolates and the majority were recovered at 3 days post vaccination suggesting such changes to be detrimental to early virus survival. Nucleotide deletions were seen only in the group given the combination of Mass and Ark. Of the 16 sequenced samples in this group, 13 contained the same AAT deletion at position 1033 1035 in the Ark strains. Findings presented in this study demonstrate alteration in the S1 nucleotide sequence following co-administration of live IBV vaccines.
The poultry red mite, Dermanyssus gallinae, is a blood feeding parasite of poultry and occasionally other animals and is recognised as one of, if not the most, important ectoparasites in poultry production across the globe. Its short lifecycle can result in large numbers of mites in a short amount of time. These explosions in populations often have adverse effects on poultry health with symptoms ranging from mild irritation and reduced productivity to death due to blood loss; the health, welfare and financial consequences of infections can be huge. Detecting burdens within poultry housing can be difficult due to the nocturnal nature of the red mite which hides in small cracks and crevices during the day. Due to this, quantifying the level of infection is also of concern with some burdens being missed until an increase in mortality is noted. Treatment is equally troublesome due to poultry housing design and the limited options of approved products.
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