Hendra virus (formerly called equine morbillivirus) is a member of the family Paramyxoviridae. The virus was first isolated in 1994 from specimens obtained during an outbreak of respiratory and neurologic disease in horses and humans in Hendra, a suburb of Brisbane, Australia. The natural reservoir for Hendra virus is thought to be flying foxes (bats of the genus Pteropus) found in Australia.
Only three human cases of Hendra virus disease have been recognized. Two of the three individuals known to be infected had a respiratory illness with severe flu-like signs and symptoms. One of the three Hendra virus infections was marked by a delayed onset of progressive encephalitis and two of the three human patients infected with Hendra virus died (CDC: Hendra virus).
4. Host Ranges and Animal Models
Hendra virus (HeV) is a highly pathogenic paramyxoviruses that continues to cause morbidity and mortality in animals and humans. Flying foxes in the genus Pteropus are considered to be the natural reservoir for both viruses and their geographic distribution encompasses all locations where HeV outbreaks have occurred. HeV has appeared sporadically in Australia since 1994 where infection has been predominantly in horses, although human infection has also occurred (McEachern et al., 2008).
Molecule Role Annotation :
A subunit vaccine formulation containing only recombinant, soluble, attachment glycoprotein G from HeV (sG(HeV)) and CpG adjuvant was evaluated as a potential NiV vaccine in the cat model. Upon oronasal challenge with NiV (50,000TCID50), all vaccinated cats were protected from disease although virus was detected on day 21 post-challenge in one animal (McEachern et al., 2008).
Description:
CpG oligodeoxynucleotide (ODN) 2007 (TCGTCGTTGTCGTTTTGTCGTT) containing a fully phosphorothioate backbone was purchased from Coley Pharmaceutical Group (Wellesley, MA, USA) and Allhydrogel™ was purchased from Accurate Chemical & Scientific Corporation (Westbury, NY, USA). Vaccine doses containing fixed amount of ODN 2007, varying amounts of sGHeV and aluminum ion (at a weight ratio of 1:25) were formulated as follows: 50 μg dose: 50 μg sGHeV, 1.25 mg aluminum ion and 150 μg of ODN 2007; 25 μg dose: 25 μg sGHeV, 625 μg aluminum ion and 150 μg of ODN 2007; and 5 μg dose: 5 μg sGHeV, 125 μg aluminum ion and 150 μg of ODN 2007. For all doses, Allhydrogel™ and sGHeV were mixed first before ODN 2007 was added. Each vaccine dose was adjusted to 1 ml with PBS and mixtures were incubated on a rotating wheel at room temperature for at least 2–3 h prior to injection (McEachern et al., 2008).
Vaccination Protocol:
Eight adult cats were immunised intramuscularly with vaccine preparations on day 0 and on day 21. Each cat received the same 1 ml dose for both prime and boost injections. All vaccine doses were given via intramuscular injection. Two animals received 50 μg doses (cat 29-50 and cat 30-50), two animals received 25 μg doses (cat 31-25 and cat 32-25), two animals received 5 μg doses (cat 33-5 and cat 34-5) and two animals received adjuvant-alone (cat 27-0 and cat 28-0). Each dose group contained one male and one female cat (McEachern et al., 2008).
Challenge Protocol:
On day 42, all animals were inoculated oronasally with 50,000 TCID50 of a low passage NiV isolate (EUKK 19817; stock virus titre 4.3 × 106 TCID50/ml) prepared as described previously [29]. Cats were assessed daily and scored out of 10 for a range of clinical observations, including alertness, grooming behavior, curiosity, depression, food consumption, faeces production and respiration rate (McEachern et al., 2008).
Efficacy:
A subunit vaccine formulation containing only recombinant, soluble, attachment glycoprotein G from HeV (sG(HeV)) and CpG adjuvant was evaluated as a potential NiV vaccine in the cat model. Upon oronasal challenge with NiV (50,000TCID50), all vaccinated cats were protected from disease although virus was detected on day 21 post-challenge in one animal (McEachern et al., 2008).
