Background

Rabbit hemorrhagic disease (RHD) is an acute infectious disease that damages the rabbit industry by producing significant mortality rates in young and adult rabbits. RHD is better controlled by vaccination.

Objective

The current study's goal was to prepare and evaluate the immuno-enhancing effect of montanide ISA70 and aluminum hydroxide (Al(OH)₃) gel incorporated within the inactivated RHDV2 vaccine and assess the vaccine's protective efficacy against the homologous and heterologous local RHDV2 strains in rabbits.

Methods

Inactivated RHDV vaccines were prepared using Montanide ISA70 oil or Al(OH)₃ gel adjuvants and submitted to sterility, safety, and potency tests. 200 rabbits were equally divided into 4 groups: G1 (control), G2 (vaccinated with gel-incorporated vaccine), G3 (vaccinated with montanide-incorporated vaccine), and G4 (vaccinated with gel- and montanide-incorporated vaccines). Individual blood samples were collected from one week to six months from all groups. The vaccine's potency was measured by the HI test and protection percentage post challenge.

Results

Data revealed slightly increasing HI titer means reaching the 1st peak at 4 weeks post-vaccination (7.33, 7.67, and 7.33 log2 in the 2nd, 3rd, and 4th groups, respectively), then slightly decreasing and peaked again, giving 9.33 log2 for the2^nd group at 3 months post-vaccination (MPV), 10.67 log2 for 3rd the group, and 10.33 log2 for the 4th group at 5 months post-vaccination. Titer gradually decreased but remained protective. The protection rate ranged from 80–100% and 80–90% for homologous and heterologous local RHDV2 vaccines, respectively, within 3 weeks and 6 months post-challenge. The montanide oil RHDV2 vaccine induced better protection than the aluminum gel RHDV2 vaccine.

Conclusion

The results demonstrated evidence of cross-protection between RHDV2 strains. The oil emulsion vaccine induced higher and longer-lasting antibody titers than those obtained with the RHDV2 aluminum gel vaccine.

A significant event occurred in Egypt in 1991 when Rabbit Hemorrhagic Disease (RHD) was introduced, causing a serious threat to the rabbit industry. Because of its high morbidity and mortality, RHDV is an industry-destructive agent, causing financial losses in Egypt's production of rabbits. RHDV is a lagovirus, a member of the Caliciviridae family, which is the cause of RHD. Three RHD outbreaks have been identified in Egypt, the first, related to the classical RHD virus (RHDV), occurred in 1991; The second type, known as the variant virus (RHDVa), occurred in 2007; and the third, known as the variant virus (RHDVb/RHDV2), was identified in 2018, and the first part of 2019. RHD can affect rabbits of all ages, both domestic and wild. There are three ways that RHD manifests, per-acute, acute, and subacute or chronic forms. Rates of mortality are often extremely high, particularly during per acute and acute phases, and are linked to necrotic hepatitis. and disseminated intravascular coagulopathy. The liver, lungs, and spleen have been found to have the most significant lesions. The diagnosis of RHDV relies on clinical picture and laboratory investigations such as molecular, histological and serological techniques can be used. Despite the availability of RHDV vaccinations, outbreaks of the virus continue to occur in several Upper and Lower governorates in Egypt. Therefore, the most significant factors of prevention and control methods are the use of preventative inactivated vaccines in conjunction with the carrying out of sanitary measures. So, in this overview study, the epidemiology, clinical and laboratory diagnosis, prevention, and control …1

 Even among vaccinated rabbits, the virus that causes rabbit viral hemorrhagic disease (RHDV) has been increasing in Egypt recently. So, the current study screened the emergent RHDV of vaccinated and unvaccinated domestic rabbits in some Egyptian provinces between 2022 and 2023. 40 pooled Samples were collected from different rabbit flocks with age range of 2 months up to 4 months with high mortality rates, clinical symptoms, and post-mortem lesions related to RHDV. Hemagglutination (HA) test, reverse transcriptase-polymerase chain reaction (RT-PCR) targeting the partial VP60 and sequencing and phylogenetic analysis were conducted for genotyping of RHDV strains. The results revealed that 16 out of 40 cases that were positive for RHDV and were hemagglutinin-positive, with titer ranging from 23 to 214. Randomly six isolates were selected for genetic sequence and phylogenetic analysis which revealed their clustering with RHDV2 strains which were detected for the first time in Upper Egypt and submitted on GenBank as (OQ925947 Assiut .vac1 to OQ925952Assiut .vac6). The nucleotide sequence identities of the six isolates were 98.8-100 % compared to each other. The recently isolated strains had nucleotide difference 23, 1 % when compared to commonly vaccinal strain (JQ995154Giza 2006). The inoculated rabbits expressed RHDV-typical signs and postmortem findings and Ninety percent (90 %) mortality rate was recorded within3–6 days post-infection. Microscopic examination revealed that presence of acute necrotizing hepatitis, congestion and widespread hemorrhages in all internal organs; liver, lungs, spleen, kidneys and brain. In conclusion, the presence of RHDV2 strains was detected for the first time in some Upper Egypt provinces.

Infectious serositisis a considerable economic problem in duck industry caused by Riemerella anatipestifer. The current study was conducted to investigate the circulating R. anatipestifer in ducks in Assiut Province and assessing their antimicrobial susceptibility. One-hundred and twenty diseased or freshly dead ducks aging 1-18 weeks were examined. Naturally infected birds showed respiratory, nervous, and locomotor disturbances, and low body weight. R. anatipestifer was detected in 16.6% (20) of birds. Among the bacteriologically positive 20 birds, only 10 could be identified by PCR as R. anatipestifer with a prevalence rate of 8.33%. The sensitivity biogram revealed that all the obtained isolates were sensitive to amoxicillin, doxycycline, and flumequine while resistance to streptomycin, chloramphenicol, ampicillin, erythromycin, spectinomycin, and cephradine was observed. On the basis of MIC, all isolates had 90- 100% sensitivity to doxycycline and amoxicillin, respectively. Experimentally, the isolated R.anatipestifer strains showed pathogenicity to 14-days-old ducklings.

Abstract

Background

Rabbit hemorrhagic disease (RHD) is an acute infectious disease that damages the rabbit industry by producing significant mortality rates in young and adult rabbits. RHD is better controlled by vaccination.

Objective

The current study's goal was to prepare and evaluate the immuno-enhancing effect of montanide ISA70 and aluminum hydroxide (Al(OH)₃) gel incorporated within the inactivated RHDV2 vaccine and assess the vaccine's protective efficacy against the homologous and heterologous local RHDV2 strains in rabbits.

Methods

Inactivated RHDV vaccines were prepared using Montanide ISA70 oil or Al(OH)₃ gel adjuvants and submitted to sterility, safety, and potency tests. 200 rabbits were equally divided into 4 groups: G1 (control), G2 (vaccinated with gel-incorporated vaccine), G3 (vaccinated with montanide-incorporated vaccine), and G4 (vaccinated with gel- and montanide-incorporated vaccines). Individual blood samples were collected from one week to six months from all groups. The vaccine's potency was measured by the HI test and protection percentage post challenge.

Results

Data revealed slightly increasing HI titer means reaching the 1st peak at 4 weeks post-vaccination (7.33, 7.67, and 7.33 log2 in the 2nd, 3rd, and 4th groups, respectively), then slightly decreasing and peaked again, giving 9.33 log2 for the2^nd group at 3 months post-vaccination (MPV), 10.67 log2 for 3rd the group, and 10.33 log2 for the 4th group at 5 months post-vaccination. Titer gradually decreased but remained protective. The protection rate ranged from 80–100% and 80–90% for homologous and heterologous local RHDV2 vaccines, respectively, within 3 weeks and 6 months post-challenge. The montanide oil RHDV2 vaccine induced better protection than the aluminum gel RHDV2 vaccine.

Conclusion

The results demonstrated evidence of cross-protection between RHDV2 strains. The oil emulsion vaccine induced higher and longer-lasting antibody titers than those obtained with the RHDV2 aluminum gel vaccine.

Abstract

Background

Rabbit hemorrhagic disease (RHD) is an acute infectious disease that damages the rabbit industry by producing significant mortality rates in young and adult rabbits. RHD is better controlled by vaccination.

Objective

The current study's goal was to prepare and evaluate the immuno-enhancing effect of montanide ISA70 and aluminum hydroxide (Al(OH)₃) gel incorporated within the inactivated RHDV2 vaccine and assess the vaccine's protective efficacy against the homologous and heterologous local RHDV2 strains in rabbits.

Methods

Inactivated RHDV vaccines were prepared using Montanide ISA70 oil or Al(OH)₃ gel adjuvants and submitted to sterility, safety, and potency tests. 200 rabbits were equally divided into 4 groups: G1 (control), G2 (vaccinated with gel-incorporated vaccine), G3 (vaccinated with montanide-incorporated vaccine), and G4 (vaccinated with gel- and montanide-incorporated vaccines). Individual blood samples were collected from one week to six months from all groups. The vaccine's potency was measured by the HI test and protection percentage post challenge.

Results

Data revealed slightly increasing HI titer means reaching the 1st peak at 4 weeks post-vaccination (7.33, 7.67, and 7.33 log2 in the 2nd, 3rd, and 4th groups, respectively), then slightly decreasing and peaked again, giving 9.33 log2 for the2^nd group at 3 months post-vaccination (MPV), 10.67 log2 for 3rd the group, and 10.33 log2 for the 4th group at 5 months post-vaccination. Titer gradually decreased but remained protective. The protection rate ranged from 80–100% and 80–90% for homologous and heterologous local RHDV2 vaccines, respectively, within 3 weeks and 6 months post-challenge. The montanide oil RHDV2 vaccine induced better protection than the aluminum gel RHDV2 vaccine.

Conclusion

The results demonstrated evidence of cross-protection between RHDV2 strains. The oil emulsion vaccine induced higher and longer-lasting antibody titers than those obtained with the RHDV2 aluminum gel vaccine.

Equine distal limb wounds are frequent and healed after a long time with the development of excessive granulation tissue and poor wound contraction and epithelialization. This study intended to investigate the effect of the local application of cod-liver oil on the healing of large-sized metacarpal wounds in equine. Three adult donkeys were generally anesthetized. A large-sized metacarpal full-thickness skin wound (5x10 cm) was inflected on the lateral aspect of the right forelimb. Cod liver oil was applied locally, followed by a protective bandage. Follow-up of the wound healing was evaluated at week intervals until healing was complete. Evaluation of healing was carried out by gross examination, photographing and image analysis by ImageJ software, and histopathology. Results revealed that granulation tissues filled the gap of the wound without signs of infection. Epithelialization was grossly observed by day 35. Reduction in wound size was significant by day 56 (60% reduction of the original size) and stayed significant until the end of the study. Histopathology revealed new blood vessels and epithelial hyperplasia, scar tissue heavily infiltrated with inflammatory cells at the surface of the wound area, and a moderate amount of collagen fiber. In conclusion, cod-liver oil was beneficial in the healing of surgically-induced large-sized wounds by the acceleration of epithelialization and enhancement of healthy scar formation. Therefore, it is recommended to use cod-liver oil for dressing recent surgical wounds.

Wounds of the distal limb in equines are restored after a long period with the development of excessive granulation tissues and poor wound contraction and re-epithelialization. Although, the usage of mesh implantation has been emerged in hernioplasty in animals and humans, its effects on treatment of distal limb wounds in equines are still undefined. Hence, this study was intended to inspect the impact of polypropylene mesh application on healing of large-sized metacarpal skin wounds in donkeys through gross and histopathological investigations on days 28, 56, and 84 post-wounds induction. The results revealed that granulation tissues formed over the outer surface of the polypropylene mesh and emerged from the pores of the polypropylene mesh. Re-epithelialization from the four sides of the wound in addition to wound contraction induced a significant reduction in the wound size compared to the control group. Histopathological results revealed that the healing process was superior in mesh-implanted wounds through promoting re-epithelialization, neovascularization, fibroblast proliferation, collagen maturation, and reduced scar formation. In conclusion, the polypropylene mesh was beneficial in accelerating the healing process through enhancing epithelialization, properly limiting and regulating exaggerated hyper granulation tissues, and promoting the formation of healthy skin suggesting its promising application for metacarpal skin wounds of donkeys.

Heat stress (HS) is one of the major economic problems facing the world's chicken industry. Besides decreased growth performance, HS reduces immune function in chickens. The principal part of the immunological function is the lymphatic organ. The spleen is a secondary lymphoid organ in birds. Sodium butyrate (SB) is the sodium salt of butyric acid and is suggested to be used to relieve heat stress. The current study aimed to evaluate the effect of sodium butyrate on the spleen in heat-stressed broilers. A total of 150 healthy broiler chicks (1 day old) were randomly divided into 4 groups: 1) control group fed on basal diet (BD) and normal temperature; 2) heat stress (HS) group (BD) and exposed to HS (34◦C for 8 h/day for 7 days starting from 29 days old); 3) low sodium butyrate group (BD + 0.5 g/kg SB every day and exposed to HS and 4) high sodium butyrate group (BD + 2 g/kg SB every day and exposed to HS. The spleen was harvested at the end of the experiments (36 days old). Our results revealed that HS caused severe damages, such as noticeable atrophy and loss of organization in the white pulp and hemorrhage in both white and red pulps. A low dose of SB supplementation showed full protection of the spleen tissue. However, the high dose might cause an adverse effect. In conclusion, SB especially low dose ameliorated the effect of heat stress. Therefore, we suggest using SB to face the heat stress in broilers, however with low doses.

The laryngeal mound (LM) formed the caudal part of the pharyngeal floor, which varied in position, shape, and length at different ages. This work aimed to study the morphogenesis of the LM in the embryonic and post hatching periods grossly, histologically, and by scanning electron microscopy using forty-eight Japanese quails. The LM primordia appeared on the 8th day of incubation as a raised elevation carried on a deep median symmetrical sulcus (glottis primordium). As a result of rapid differential LM parts growth, LM took different shapes with advanced ages, finally ending in a heart shape. Internally, LM was supported by hyaline laryngeal cartilages; a C-shaped cricoid cartilage that had two wings, paired fork-like two arytenoids, and a comma-shaped procricoid that had four articulations. The glottis appeared as a central longitudinal opening on the 13th day of incubation. With age advancing, it was characterized as a wide rostral commissure and a caudal narrow one that was supported on either side by arytenoid cartilages. Additionally, on the 13th day, a bilateral sagittal row to the glottis developed, consisting of 8–9 small caudally directed papillae. At that time, rostral and caudal transverse laryngeal papillary rows appeared. LM had compound tubuloalveolar submucosal laryngeal glands that were situated between M. dilator glottidis and cricohyoideus and opened on the dorsal surface of LM. Histochemically, the early post-hatching stages of the glandular secretion were PAS-positive while late post-hatching ages had alcinophilic reactions. In conclusion, the LM had rapid morphological developmental events in the early ages other than the adult ages.