Naglaa Ibrahim Aly

Background and Aim: Rabies is considered a highly fatal zoonotic disease and many deaths in humans have been associated with dog bites. This study was designed to prepare an oral anti-rabies vaccine in the form of baits to eliminate the disease in free-roaming dogs and subsequently protect humans from dog bites. Materials and Methods: The Evelyn Rokintniki Abelseth (ERA) rabies virus strain was propagated in baby hamster kidney cell cultures and adjusted to the recommended dose for application. Four forms of oral baits were employed with the rabies vaccine, which was evaluated for safety, acceptability, and potency in different dog groups. Enzyme-Linked Immunosorbent Assay (ELISA) and the serum neutralization test (SNT) were used to determine the protective rabies antibody titer in the sera of vaccinated dogs. Results: According to the results, a dose of 3 mL of the ERA strain, containing a viral titer of 107.6 TCID50/mL, induced a mean antibody titer of 25.6 by SNT, and the PI% was 75.7 by Block ELISA, providing a protective level of the rabies antibody in 100% of vaccinated dogs. All used baits were found to be safe, inducing no abnormal general post-vaccination signs (the signs are limited to mild fever, mild loss of appetite, and mild-to-moderate loss of energy for 24-36 h after vaccination). Conclusion: It was found that most of the accepted and highly potent bait types consisted of a mixture of wheat flour, vegetable oil, sodium alginate, corn starch, meat meal, cellulose gum, and water. This dog meal was covered with bran and edible wax to seal the bait cavity after inserting the vaccine sachet. This bait was able to induce a protective level of rabies antibodies in 100% of vaccinated dogs after receiving one bait/dog. Hence, such a bait could be recommended for use in the protection of free-roaming dogs and the elimination of the disease.

Background and Aim: One strategy that can be used to stabilize vaccines is to convert them into a dry powder. This can protect the integrity of the active ingredients as well as vaccine antigenicity during manufacture, storage, and transport. This study highlights the potent adjuvant activity of Carbopol® when used alone to stabilize live-attenuated Newcastle disease virus (NDV) vaccines or when used in a formulation together with skimmed milk. Tolerability and potency of these formulations were compared with those obtained from other local live NDV vaccines produced locally by the Veterinary Serum and Vaccine Research Institute. Materials and Methods: We evaluated the cellular and humoral immune responses to a locally prepared, live-attenuated LaSota virus vaccine. Vaccine formulations were stabilized with Carbopol® 940 alone or in combination with skimmed milk. Results: Our results indicate that the use of Carbopol® 940 alone to stabilize a live-attenuated LaSota vaccine resulted in enhanced cellular and humoral immunity. The antibody titer was prolonged through the 6th week post-vaccination (5.0 log2). Full (100%) protection was observed in response to challenge with very virulent NDV at day 21 after vaccination; there were no clinical signs or lesions on examination. Addition of Carbopol® 940 to the live-attenuated vaccine formulation resulted in a more compact, stable, and high-quality lyophilized cake after freeze-dried lyophilization compared with that produced by stabilization with skimmed milk alone. Conclusion: Our data suggest that Carbopol® 940 may improve clinical responses to live-attenuated vaccines.

Aim: This study aimed to detect and characterize current genotypes of canine parvovirus (CPV) in Egypt during 2018. Materials and Methods: A total of 50 fecal swabs were collected from clinically infected domestic dogs of 2-5 months of age, suspected to suffer from CPV infection, from Cairo and Giza Governorates. The samples were subjected to qualitative antigen detection using the rapid test, followed by isolation on Madin-Darby Canine Kidney (MDCK) cells, molecular characterization with partial amplification of VP2 gene using polymerase chain reaction (PCR), followed by sequencing and phylogenetic analysis. Results: Out of 50 fecal samples, 20 samples were positive (40%) by Rapid CPV/canine coronavirus Ag Test Kit. These positive samples were cultured successfully on MDCK cells. Nine randomly chosen samples out of 30 apparently negative samples were amplified using PCR with primers Hfor and Hrev to yield a typical 630 bp fragment. Then, six randomly chosen samples out of nine were amplified using PCR with primers Pbs and Pbas to yield a typical 427 bp fragment. Sequencing, BLAST analysis and assembly of the two fragments (630 bp and 427 bp) to produce 912 bp fragments, in the six samples, revealed two serotypes CPV-2b and CPV-2c. The obtained strains were submitted to GenBank and given accession numbers MK642272, MK642273, MK642274, MK642275, MK642276, and MK642277. Phylogenetic analysis of the Egyptian strains serotype 2b illustrated that they were closely related to Thailand strains (accession numbers KP715709, KP715694, KP715701, and KP715700); while Egyptian strains serotype 2c was closely related to Thailand strains (accession numbers MH711894 and MH711902), Taiwanese strain (KU244254), Chinese strain (MF467242), and Vietnamese strain (accession number LC216910). Conclusion: The current research recommends further epidemiological studies to assess the extent of the occurrence of different serotypes of CPV in Egypt and the efficiency of imported and locally produced vaccines in protection against CPV infection.