Severe Histopathological Lesions Research Articles

Identification, Genetic Characterization, and Pathogenicity of Three Feline Herpesvirus Type 1 Isolates from Domestic Cats in China.

(1) Background: Feline herpesvirus (FHV-1) is a significant pathogen in cats, causing respiratory and ocular diseases with consequential economic and welfare implications. (2) Methods: This study aimed to isolate and characterize FHV-1 from clinical samples and assess its pathogenicity. We collected 35 nasal and ocular swabs from cats showing symptoms of upper respiratory tract infection and FHV positivity detected by polymerase chain reaction (PCR). Viral isolation was carried out using feline kidney (F81) cell lines. Confirmation of FHV-1 presence was achieved through PCR detection, sequencing, electron microscopy, and indirect immunofluorescence assay. The isolated strains were further characterized by evaluating their titers, growth kinetics, and genetic characteristics. Additionally, we assessed the pathogenicity of the isolated strains in a feline model, monitoring clinical signs, viral shedding, and histopathological changes. (3) Results: Three strains of FHV-1 were isolated, purified, and identified. The isolated FHV-1 strains exhibited high homology among themselves and with domestic isolates and FHV-1 viruses from around the world. However, they showed varying degrees of virulence, with one strain (FHV-A1) causing severe clinical signs and histopathological lesions. (4) Conclusion: This study advances our understanding of the genetic and pathogenic characteristics of FHV-1 in China. These findings underscore FHV-A1 isolate as a potentially ideal candidate for establishing a challenge model and as a potential vaccine strain for vaccine development.

Isolation and pathogenicity comparison of two novel natural recombinant porcine reproductive and respiratory syndrome viruses with different recombination patterns in Southwest China.

Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses in the swine industry. Frequent mutations and recombinations account for PRRSV immune evasion and the emergence of novel strains. In this study, we isolated and characterized two novel PRRSV-2 strains from Southwest China exhibiting distinct recombination patterns. They were designated SCABTC-202305 and SCABTC-202309. Phylogenetic results indicated that SCABTC-202305 was classified as lineage 8, and SCABTC-202309 was classified as lineage 1.8. Amino acid mutation analysis identified unique amino acid substitutions and deletions in ORF5 and Nsp2 genes. The results of the recombination analysis revealed that SCABTC-202305 is a recombinant with JXA1 as the major parental strain and NADC30 as the minor parental strain. At the same time, SCABTC-202309 is identified as a recombinant with NADC30 as the major parental strain and JXA1 as the minor parental strain. In this study, we infected piglets with SCABTC-202305, SCABTC-202309, or mock inoculum (control) to study the pathogenicity of these isolates. Although both isolated strains were pathogenic, SCABTC-202305-infected piglets exhibited more severe clinical signs and higher mortality, viral load, and antibody response than SCABTC-202309-infected piglets. SCABTC-202305 also caused more extensive lung lesions based on histopathology. Our findings suggest that the divergent pathogenicity observed between the two novel PRRSV isolates may be attributed to variations in the genetic information encoded by specific genomic regions. Elucidating the genetic determinants governing PRRSV virulence and transmissibility will inform efforts to control this devastating swine pathogen.IMPORTANCEPorcine reproductive and respiratory syndrome virus (PRRSV) is one of the most critical pathogens impacting the global swine industry. Frequent mutations and recombinations have made the control of PRRSV increasingly difficult. Following the NADC30-like PRRSV pandemic, recombination events involving PRRSV strains have further increased. We isolated two novel field PRRSV recombinant strains, SCABTC-202305 and SCABTC-202309, exhibiting different recombination patterns and compared their pathogenicity in animal experiments. The isolates caused higher viral loads, persistent fever, marked weight loss, moderate respiratory clinical signs, and severe histopathologic lung lesions in piglets. Elucidating correlations between recombinant regions and pathogenicity in these isolates can inform epidemiologic tracking of emerging strains and investigations into viral adaptive mechanisms underlying PRRSV immunity evasion. Our findings underscore the importance of continued genomic surveillance to curb this economically damaging pathogen.

Kaempferol mitigates reproductive dysfunctions induced by Naja nigricollis venom through antioxidant system and anti-inflammatory response in male rats

Naja nigricollis Venom (NnV) contains complex toxins that affects various vital systems functions after envenoming. The venom toxins have been reported to induce male reproductive disorders in envenomed rats. This present study explored the ameliorative potential of kaempferol on NnV-induced male reproductive toxicity. Fifty male wistar rats were sorted randomly into five groups (n = 10) for this study. Group 1 were noted as the control, while rats in groups 2 to 5 were injected with LD50 of NnV (1.0 mg/kg bw; i.p.). Group 2 was left untreated post envenomation while group 3 was treated with 0.2 ml of polyvalent antivenom. Groups 4 and 5 were treated with 4 and 8 mg/kg of kaempferol, respectively. NnV caused substantial reduction in concentrations of follicle stimulating hormone, testosterone and luteinizing hormone, while sperm motility, volume and counts significantly (p < 0.05) decreased in envenomed untreated rats. The venom enhanced malondialdehyde levels and substantially decreased glutathione levels, superoxide dismutase and glutathione peroxidase activities in the testes and epididymis of envenomed untreated rats. Additionally, epididymal and testicular myeloperoxidase activity and nitric oxide levels were elevated which substantiated severe morphological defects noticed in the reproductive organs. However, treatment of envenomed rats with kaempferol normalized the reproductive hormones with significant improvement on sperm functional parameters. Elevated inflammatory and oxidative stress biomarkers in testis and epididymis were suppressed post kaempferol treatment. Severe histopathological lesions in the epididymal and testicular tissues were ameliorated in the envenomed treated groups. Results highlights the significance of kaempferol in mitigating reproductive toxicity induced after snakebite envenoming.

Histomolecular profile of Helicobacter pylori strains circulating in Brazzaville (Congo).

Helicobacter pylori (Hp) infection is a real public health problem in the Congo. We aimed study the histomolecular profile of Hp strains circulating in Brazzaville, Congo, in order to contribute to the improvement of Hp-infected patients in the country. This was an analytical-transversal study carried out from January to November 2020 (i.e. a study period of 11 months) in the endoscopy centers of Brazzaville as well as the molecular biology and anatomopathology laboratories of Pointe-Noire and Oyo. It involved 100 symptomatic patients over the age of 18 referred for upper GI endoscopy. These patients underwent gastric biopsies for histopathological analysis according to the Sydney classification and molecular analysis using the real-time polymerase chain reaction (PCR) technique. The frequency of Hp infection was determined using real-time PCR. PCR was also used to identify the Hp strains and assess their tropism in the gastric mucosa. Digestive symptoms, endoscopic lesions, and histopathological lesions associated with HP infection were studied. The incidence of Hp infection was 91%, with a female predominance of 52.75% and an average age of 46.32 years. Endoscopy revealed normal mucosa (56.14%), ulcerated lesions (12.28%), and gastritis (22.81%) in infected patients. Histopathologically, the lesions were chronic atrophic gastritis (91%), with inflammatory activity (16.46%), intestinal metaplasia (16.46%), and adenocarcinoma (3.3%). Cag A strains were present in 85.71% of cases and had no preferential tropism in the gastric mucosa. Strains carrying the Cag A gene were present in severe and serious endoscopic and histopathological lesions. The prevalence of Hp infection is 91% in the Brazzaville population. Cag A strains circulate in high proportions and are implicated in the occurrence of severe lesions of the gastric mucosa.

Pathogenicity and horizontal transmission evaluation of a novel isolated African swine fever virus strain with a three-large-fragment-gene deletion

African swine fever has caused substantial economic losses to China`s pig industry in recent years. Currently, the highly pathogenic African swine fever virus strain of genotype II is predominantly circulating in China, accompanied by a series of emerging isolates displaying unique genetic variations. The pathogenicity of these emerging strains is still unclear. Recently, a novel ASFV strain with a distinguishable three-large-fragment gene deletion was obtained from the field specimens, and its in vivo pathogenicity and transmission were evaluated in this study. The animal experiment involved inoculating a high dose of YNFN202103 and comparing its effects with those of the highly pathogenic strain GZ201801_2. Results showed that pigs infected by YNFN202103 exhibited significantly prolonged onset and survival time, lower viremia levels, and less severe histopathological lesions compared to GZ201801_2. These findings contributed valuable insights into the pathogenicity and transmission of ASFV and its prevention and eradication strategies in practical settings.

Genetic and pathogenic characterization of an NADC-34-like isolate of porcine reproductive and respiratory syndrome virus.

In this study, an NADC34-like strain of porcine reproductive and respiratory syndrome virus (PRRSV), YC-2020, was isolated from a pig farm in Yuncheng, Shanxi Province, China. Phylogenetic and molecular evolutionary analysis showed that the genome sequence of YC-2020 was very similar to those of NADC34-like PRRSV strains in the ORF2-7 region. However, it was more closely related to NADC30-like PRRSV and highly pathogenic (HP) PRRSV in the NSP2 and NSP3-9 coding regions, respectively, suggesting that recombination had occurred between viruses belonging to lineages 1 and 8. Piglets infected with YC-2020 exhibited mild clinical signs, but they had severe histopathological lesions in their lungs. These findings reveal novel genetic and pathogenic features of this isolate.

Aerosol vaccination of chicken pullets with irradiated avian pathogenic Escherichia coli induces a local immunostimulatory effect.

The present study investigated the expression of cytokines and cellular changes in chickens following vaccination with irradiated avian pathogenic Escherichia coli (APEC) and/or challenge. Four groups of 11-week-old pullets, each consisting of 16 birds were kept separately in isolators before they were sham inoculated (N), challenged only (C), vaccinated (V) or vaccinated and challenged (V+C). Vaccination was performed using irradiated APEC applied via aerosol. For challenge, the homologous strain was administered intratracheally. Birds were sacrificed on 3, 7, 14 and 21 days post challenge (dpc) to examine lesions, organ to body weight ratios and bacterial colonization. Lung and spleen were sampled for investigating gene expression of cytokines mediating inflammation by RT-qPCR and changes in the phenotype of subsets of mononuclear cells by flow cytometry. After re-stimulation of immune cells by co-cultivation with the pathogen, APEC-specific IFN-γ producing cells were determined. Challenged only birds showed more severe pathological and histopathological lesions, a higher probability of bacterial re-isolation and higher organ to body weight ratios compared to vaccinated and challenged birds. In the lung, an upregulation of IL-1β and IL-6 following vaccination and/or challenge at 3 dpc was observed, whereas in the spleen IL-1β was elevated. Changes were observed in macrophages and TCR-γδ+ cells within 7 dpc in spleen and lung of challenged birds. Furthermore, an increase of CD4+ cells in spleen and a rise of Bu-1+ cells in lung were present in vaccinated and challenged birds at 3 dpc. APEC re-stimulated lung and spleen mononuclear cells from only challenged pullets showed a significant increase of IFN-γ+CD8α+ and IFN-γ+TCR-γδ+ cells. Vaccinated and challenged chickens responded with a significant increase of IFN-γ+CD8α+ T cells in the lung and IFN-γ+TCR-γδ+ cells in the spleen. Re-stimulation of lung mononuclear cells from vaccinated birds resulted in a significant increase of both IFN-γ+CD8α+ and IFN-γ+TCR-γδ+ cells. In conclusion, vaccination with irradiated APEC caused enhanced pro-inflammatory response as well as the production of APEC-specific IFN-γ-producing γδ and CD8α T cells, which underlines the immunostimulatory effect of the vaccine in the lung. Hence, our study provides insights into the underlying immune mechanisms that account for the defense against APEC.

Acute Toxicity Effect of Crude Leaves Extract of Thevetia peruviana on Full Blood Count and some Organs of Clarias gariepinus Juveniles

Background: Many toxicity studies have shown that heamatological and histological alterations are widely used as good bioindicators in determining the effect of toxicants on fish. This study investigated the acute toxicity effects of the leaf extract of Thevetia peruviana on full blood count parameters and some organs of Clarias gariepinus juveniles”. Methods: One hundred and twenty C. gariepinus mixed sex juveniles were exposed to acute con-centrations (0.63, 1.25, 2.50, 5.00, and 10.00g/L ) of leave extract of T. peruviana in twelve 20 L capacity rectangular glass tanks with six treatments and bi-replicated. Blood for full blood count was collected through cardiac puncture while gills and liver were excised and analyzed for histo-pathological alterations. Results: PCV, RBC, Hb, Neu, and Lym of C. gariepinus juveniles inversely decreased while WBC directly increased with acute concentrations of T. peruviana leaves extract. The microscopic examination of the gills revealed concentration-dependent histo-architectural alterations expressed as epical clubbing, haemorrhage, desquamation, atrophy, and complete erosion of secondary lamel-lae. The liver showed moderate to severe concentration-dependent histopathological lesions typi-fied by hypertrophy, atrophy, necrosis, kupffer cell proliferation, and hepatocellular degenerations. Conclusion: Given the alterations in the blood, gills and liver noted in this study, the invasive growth of the T. peruviana plant should be controlled to minimize unwanted fish kill.

Adipose-derived mesenchymal stem cells secrete extracellular vesicles: A potential cell-free therapy for canine renal ischaemia-reperfusion injury.

Adipose-derived mesenchymal stem cells (ADMSCs) and their extracellular vesicles (EVs) are a promising source of therapies for ischaemia-reperfusion (IR) because of their potent anti-inflammatory and immunomodulatory properties. The aims of this study were to explore the therapeutic efficacy and potential mechanism of ADMSC-EVs in canine renal IR injury. Mesenchymal stem cells (MSCs) and EVs were isolated and characterised for surface markers. A canine IR model administered with ADMSC-EVs was used to evaluate therapeutic effects on inflammation, oxidative stress, mitochondrial damage and apoptosis. CD105, CD90 and beta integrin ITGB were positively expressed in MSCs, while CD63, CD9 and intramembrane marker TSG101 were positively expressed in EVs. Compared with the IR model group, there was less mitochondrial damage and reduction in quantity of mitochondria in the EV treatment group. Renal IR injury led to severe histopathological lesions and significant increases in biomarkers of renal function, inflammation and apoptosis, which were attenuated by the administration of ADMSC-EVs. Secretion of EVs by ADMSCs exhibited therapeutic potential in renal IR injury and may lead to a cell-free therapy for canine renal IR injury. These findings revealed that canine ADMSC-EVs potently attenuate renal IR injury-induced renal dysfunction, inflammation and apoptosis, possibly by reducing mitochondrial damage.

Genomic and comparative clinico-pathological assessment of two Pakistani pigeon-derived newcastle disease virus sub-genotypes XXI.1.1 and XXI.1.2 isolated in 2017

Pigeon paramyxovirus type-1 (PPMV-1) is an antigenic-variant of Newcastle disease virus (NDV) which is associated with infection in Columbidae family. In this study, we isolated two pigeon-derived strains pi/Pak/Lhr/SA_1/17 (designed as SA_1) and pi/Pak/Lhr/SA_2/17 (designed as SA_2) from diseased pigeons collected in Punjab province in 2017. We performed the whole genome, phylogenetic analysis and comparative clinico-pathological evaluation of two viruses in pigeons. Phylogenetic analysis based on fusion (F) gene and complete genome sequences showed that SA_1 belonged to sub-genotype XXI.1.1 and SA_2 clustered in sub-genotype XXI.1.2. SA_1 and SA_2 viruses contributed to morbidity and mortality in pigeons. Remarkably, although the two viruses resulted in comparatively similar pattern of pathogenesis and replication ability in various tissues of infected pigeons, SA_2 could cause more severe histopathological lesions and had comparatively high replication ability in pigeons than SA_1. Moreover, pigeons infected with SA_2 had higher shedding efficiency than that of pigeons infected with SA_1. Moreover, several aa substitutions in the major functional domains of the F and HN proteins might be contributed to the pathogenic differences between the two isolates in pigeons. Overall, these findings provide us with important insight into the epidemiology and evolution of PPMV-1 in Pakistan and laid the foundation for the further elucidation of the mechanism underlying the pathogenic difference of PPMV-1 in pigeons.

Host Response of Syrian Hamster to SARS-CoV-2 Infection including Differences with Humans and between Sexes.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted the importance of having proper tools and models to study the pathophysiology of emerging infectious diseases to test therapeutic protocols, assess changes in viral phenotypes, and evaluate the effects of viral evolution. This study provided a comprehensive characterization of the Syrian hamster (Mesocricetus auratus) as an animal model for SARS-CoV-2 infection using different approaches (description of clinical signs, viral load, receptor profiling, and host immune response) and targeting four different organs (lungs, intestine, brain, and PBMCs). Our data showed that both male and female hamsters were susceptible to the infection and developed a disease similar to the one observed in patients with COVID-19 that included moderate to severe pulmonary lesions, inflammation, and recruitment of the immune system in the lungs and at the systemic level. However, all animals recovered within 14 days without developing the severe pathology seen in humans, and none of them died. We found faint evidence for intestinal and neurological tropism associated with the absence of lesions and a minimal host response in intestines and brains, which highlighted another crucial difference with the multiorgan impairment of severe COVID-19. When comparing male and female hamsters, we observed that males sustained higher viral RNA shedding and replication in the lungs, suffered from more severe symptoms and histopathological lesions, and triggered higher pulmonary inflammation. Overall, these data confirmed the Syrian hamster as a suitable model for mild to moderate COVID-19 and reflected sex-related differences in the response against the virus observed in humans.

Association between the severity of histopathological lesions and Mycobacterium avium subspecies paratuberculosis (MAP) molecular diversity in cattle in southern Chile.

The objective was to evaluate the association between the severity of histopathological lesions caused by Mycobacterium avium subspecies paratuberculosis (MAP) infection and the molecular diversity of this pathogen. Blood, ileum, and mesenteric lymph node samples were collected at slaughter, from 1,352 adult cattle [source population 1 (SP1)]. In addition, 42 dairy herds (n = 4,963 cows) were followed for 2 years, and samples from compatible paratuberculosis clinical cases [source population 2 (SP2)] were collected. MAP infection was confirmed using an ELISA test, liquid media culture, and PCR. Isolates were genotyped using five MIRU-VNTR markers. Tissues from confirmed samples were subjected to a histopathological examination. A histopathological severity score (HSS) system was developed and used to grade (0 to 5) the magnitude of lesions caused by MAP. In general, the HSS system assesses the number of foci and degree of macrophage infiltration, together with the presence of multinucleated giant cells (MGCs) and acid-fast bacilli (AFB), in addition to the fusion of the intestinal villi and hyperplasia of the crypts. Despite the large sampling effort, only 79 MAP isolates were successfully genotyped, where 19 different haplotypes were described. A mixed-effect Poisson regression model was used to assess the relationship between haplotypes and HSS values. The model was controlled by animal age, and the farm was used as a random effect. Haplotypes were grouped based on their relative frequency: the most frequent haplotype (group i, 49.4%), the second most frequent haplotype (group ii, 12.7%), and all other haplotypes (group iii, 37.9%). Model outputs indicated that group i had significantly higher HSS values than group iii. In addition, group i was also associated with higher optical density (OD) values of the ELISA test. These results support the existence of differences in pathogenicity between MAP haplotypes. However, results were based on a relatively small sample size; thus, these should be taken with caution. Despite this, study findings suggest that haplotypes would be associated with differences in disease progression, where the dominant haplotype tends to generate more severe lesions, which could be linked to a greater shed of MAP cells than non-dominant haplotypes, increasing their chances of transmission.

Evaluation of Spirulina Platensis Efficacy Against Local Field Vvibdv Challenge in Broiler Chickens

The antiviral and immunostimulant effect of dietary supplementation of Spirulina platensis (SP) against Infectious bursal disease (IBD) was assessed as follows; 126 one-day-old cobb broiler chicks were randomly distributed into six groups (21 birds/group with three replicates, 7 birds each): negative control (non-vaccinated, and non-challenged ; NC), positive control (non-vaccinated, and challenged; PC), vaccinated control (vaccinated, and challenged; VC), Spirulina 0.1% (vaccinated, 0.1% SP-supplemented, and challenged; VSP-0.1), Spirulina 0.3% (vaccinated, 0.3% SP-supplemented, and challenged; VSP-0.3), and Spirulina 0.5% (vaccinated, 0.5% SP-supplemented, and challenged; VSP-0.5). The chicks in NC, PC, and VC groups were not supplemented with SP. All vaccinated groups, regardless SP supplementation, showed significant improvement of body weight gain (19% in 0.3% SP) and FCR during IBDv challenge (10 dpc) (P˂0.05). On the 10th dpc, IBD ELISA titer in SP-supplemented groups were decreased (P&gt;0.05) than that of G3, suggesting an antiviral efficacy of SP. This antiviral activity was evident by the viral RNA load in the cloacal swabs as well. The viral shedding peak was on the 5th day pc which was significantly decreased on G4-6 (P˂0.05) in comparison to G2 and G3. Also, the bursal ratio was improved in SP supplemented groups comparable to G3. Moreover, in unchallenged broilers, the gene expression of INF-γ and IL-18 were upregulated while that of IL-10 was downregulated in spleen of SP-supplemented chicks. Finally, severe histopathological lesions of kidneys, bursa, thymus, and spleen were observed in G2 which moderately minimized in G3 and were more alleviated in SP-supplemented groups. Collectively, SP supplementation improved body weight gain and decreasing viral shedding with antiviral activity. The mechanisms of SP against IBDV challenge may include cell-mediated immunity promoting effect, antiviral activity, and/or anti-inflammatory effect that should be further studied

First report of Ambiphrya species (Ciliophora, Peritrichia) infestation in farmed Micropterus salmoides and Ictalurus punctatus in China

Infestation by parasites is a serious problem in the aquaculture industries of Micropterus salmoides Lacepède, 1802 and Ictalurus punctatus Rafinesque, 1818. Herein, Ambiphrya species are reported for the first time and cause high infestation intensity to M. salmoides and I. punctatus in China. The infestation rate of each parasite on its host was 100%, and the disease outbreaks caused 100% mortality in M. salmoides and severe histopathological lesions of gills of I. punctatus. Subsequently, we combined living observation, silver staining and scanning electron microscope to identify the Ambiphrya species. The ciliates from M. salmoides and I. punctatus were identified as Ambiphrya tholiformis Surber, 1943 and Ambiphrya ameiuri Thompson et al., 1947, respectively. Furthermore, the small ribosomal subunit (SSU) rDNA sequences of the two Ambiphrya species was obtained for the first time for further identification and phylogenetic analyses. Surprisingly, the results showed that the two Ambiphrya species formed a monophyletic clade within the family of Zoothamniidae, indicating that the genus Ambiphrya should be separated from the family Scyphidiidae. Meanwhile, A. tholiformis and A. ameiuri might be co-introduced into China along with M. salmoides and I. punctatus. Co-introduction of parasites could infest native species and cause new disease outbreaks. Therefore, more attention should be focused on detecting and monitoring the parasites of introduced fishes.

Novel insights on the potential activity of propolis and wheat germ oil against chronic toxoplasmosis in experimentally infected mice

The use of apitherapy and natural herbal medicines for combating toxoplasmosis has garnered major attention from many researchers. However, there is no available information regarding the potential use of a combination of propolis and wheat germ oil (WGO) in the treatment of toxoplasmosis. In the present study, the potential effects of propolis, WGO, and their combination in the treatment of chronic toxoplasmosis in Swiss albino mice were investigated. Following induction of chronic toxoplasmosis, the potential antiparasitic effects of these substances were evaluated by parasitological assessment and by counting of Toxoplasma cysts. Additionally, the effects of the treatments on parasite loads were analyzed using TaqMan real-time quantitative PCR targeting the Toxoplasma P29 gene followed by investigation of the major histopathological changes in the brain, uterus, and kidney. Interestingly, the combination of propolis and WGO significantly (P ≤ 0.05) decreased the parasite burden in experimental animals compared with burdens seen in groups treated with propolis or WGO alone. Furthermore, the quantification of the DNA concentrations of Toxoplasma P29 gene after the treatment with propolis and WGO revealed a reduction in parasite load in treated groups versus the control group (infected untreated animals). Importantly, the severity of histopathological lesions was significantly (P ≤ 0.05) improved following treatment with propolis and WGO. Collectively, the present study indicated a potential novel role for propolis and WGO as an active apitherapy and natural herbal medication for treating chronic toxoplasmosis, combat the disease, and which could also help overcome the side effects of chemical drugs.

Pathological and Immuno-Molecular Examination of Protozoa in Aborted Fetus's and Placenta of Iraqi Cattle (A case report)

Tissue samples of placenta and aborted fetus were collected from aborted cow and preserved in 10% formalin buffered saline for routine histopathology stained with H&amp;E and for immunohistochemistry to detect TNF-a marker. Pathological examination showed necrotic foci with abscesses mainly around site of invasive protozoa. Immuno-Molecular examination showed marked deposition of TNF marker in tissue, mainly brain of fetus, which refers to genetic damage in gene responsible for controlling TNF values. It is concluded that protozoal infection with Neospora caninum can cause abortion in cattle at advanced stage (8th month ) of gestation with severe histopathological lesions on placenta as well as the brain of fetus. This case report is an update for the information presented in the Proceedings of the 3rd Scientific Conference of the Faculty of Veterinary Medicine / University of Kerbala on 10th April 2017.

Effect of inhibition of Toll-like receptor 3 signaling on pathogenesis of rabies virus in mouse model

Rabies is a zoonotic viral disease with inevitably fatal outcome. Toll-like receptor 3 (TLR3) could sense dsRNA viral infections, and implicated in pathogenesis of rabies and Negri bodies (NBs) formation. Present study was undertaken to elucidate the role of TLR3 in pathogenesis, NBs formation, and therapeutic potential of blocking TLR3/dsRNA interaction in rabies infection. Young Swiss albino mice were infected with 100 LD50 of street rabies virus (SRABV) intracerebrally (i/c) on day 0 and treated with 30 μg of CU CPT 4a (selective TLR3 inhibitor) i/c on 0, 3 and 5 days post-infection (DPI). Three mice each were sacrificed at 1, 3, 5, 7, 9, 11, and 13 DPI to study sequential pathological consequences through histopathology, Seller's staining, immunofluorescence, immunohistochemistry, TUNEL assay, flow cytometry, and viral and cytokine genes quantification by real-time PCR. CU CPT 4a inhibited TLR3 expression resulted in delayed development and decreased intensity of clinical signs and pathological lesions, low viral load, significantly reduced NBs formation, and increased survival time in SRABV-infected mice. These parameters suggested that TLR3 did influence the SRABV replication and NBs formation. Inhibition of TLR3 led to decreased expression of pro-inflammatory cytokines and interferons indicated an anti-inflammatory effect of CU CPT 4a during SRABV infection. Further, TLR3-inhibited group revealed normal CD4+/CD8+ T-cells ratio with less TUNEL-positive apoptotic cells indicated that immune cell kinetics are not affected during TLR3-inhibition. SRABV-infected and mock-treated mice were developed severe clinical signs and histopathological lesions, more NBs formation, high viral load, increased pro-inflammatory cytokines expression in brain, which were correlated with higher expression levels of TLR3. In conclusion, these data suggested that TLR3/dsRNA signaling pathway could play critical role in pathogenesis of SRABV infection in vivo and opens up new avenues of therapeutics.

Recombinant characteristics, pathogenicity, and viral shedding of a novel PRRSV variant derived from twice inter-lineage recombination

Porcine reproductive and respiratory syndrome (PRRS), caused by the PRRS virus (PRRSV), is a significant threat to the global pig industry. In this study, a novel recombinant PRRSV, SD043, was isolated from a pig farm experiencing disease in 2019. Phylogenetic analysis revealed that SD043 belonged to lineage 1 of PRRSV-2 while recombination analyses revealed that it is a recombinant virus from lineage 1 and lineage 8 strains. Based on further analysis, SD043 underwent recombination twice. Pathogenicity studies revealed that SD043 causes mild clinical symptoms, thymus atrophy, and severe histopathological lesions in the lungs. Notably, virus shedding in SD043-infected piglets was detectable at 10 days post-inoculation with a high viral load in the respiratory or digestive tract, indicating that the recombinant PRRSV appears to shed higher numbers of virus. Furthermore, genomic surveillance based on all available PRRSVs circulating in Shandong province revealed an increasing increase in recombinant PRRSV since 2015, with the recombinant pattern (between lineages 1 and 8) being the same as that of SD043. These findings enable a better understanding of the process of twice recombination and virus shedding of recombinant PRRSV and can strengthen the prevention and control of the PRRSV epidemic.

Reação traqueal pós-vacinal à diferentes cepas do vírus da doença de Newcastle

ABSTRACT: The aim of the present study was to evaluate the post-vaccinal reaction to two lentogenic vaccine strains of Newcatle disease virus (NDV) and a recombinant turkey herpesvirus (rHVT) vaccine expressing the fusion glycoprotein of NDV in broiler chickens through histomorphometric and histopathologic analyses of the trachea. The experiment involved 245 chicks housed in randomized blocks with three different enclosures under controlled conditions of temperature, light and ventilation. Each enclosure represented a vaccine strain and was divided into groups according to the administration route. Each block also had its own control group composed of unvaccinated birds. The vaccine strains PHY.LMV.42 (PL42) and La Sota (LS) were selected according to the Intracerebral Pathogenicity Index (ICPI) and the rHVT-NDV Serotype 3 strain (ST3) was selected for representing non-NDV infection. At two, four, seven, 14 and 21 days post vaccination, fragments from the middle third of the trachea were collected and submitted to routine histological processing. For the histomorphometric analysis, the slides were photographed, and the thickness of the tracheal mucosa was measured. Statistical analysis involved two-way ANOVA and Tukey’s post-hoc test with a 5% significance level. For the histopathological evaluation, lesions were described as to the degree of intensity and distribution. At four and 14 days post vaccination with the LS strain administered by the ocular route, the means of thickening of the tracheal mucosa (20.85±7.31μm and 26.97±5.50μm, respectively) were significantly higher (p&lt;0.05) than for all other strains, which was related to the severe histopathological lesions found in this group, characterized by hyperemia, hyperplasia of the mucous glands, moderate deciliation and multifocal lymphohistiocytic inflammatory infiltrate. At 21 days, broiler chickens vaccinated with the ST3 strain showed more discrete lesions and less thickening of the tracheal mucosa (23.23±7.62μm; p&lt;0.05) in comparison with other studied strains. The lesions found in this group were only hemorrhage, deciliation and mild focal lymphocytic inflammatory infiltrate. The results of the histomorphometry and histopathology of the trachea indicated that vaccination with rHVT-NDV Serotype 3 strain induced lower degree post-vaccine tracheal lesions compared to other vaccine strains analyzed in this study.

Comparative Pathogenicity of Aeromonas spp. in Cultured Red Hybrid Tilapia (Oreochromis niloticus × O. mossambicus).

Simple SummaryRecently, there has been an emergence of a hypervirulent pathotype of Aeromonas hydrophila, vAh strain. The strain was responsible for the acute mass mortalities among catfish in the USA. One of the unique abilities of the vAh strain is to utilize myo-inositol as a sole carbon source and this ability has been linked to contribute to its virulence. Therefore, the present study was carried out to screen and assess the virulence of myo-inositol-utilizing strains among Aeromonas spp. in Malaysia. Out of the 124 Aeromonas isolates screened, only A. dhakensis strain 1P11S3 was able to utilize myo-inositol as a sole carbon source. The only myo-inositol-utilizing strain was compared with five non-myo-inositol-utilizing Aeromonas spp. in an experimental challenge test using red hybrid tilapia (Oreochromis mossambicus × O. niloticus). Our findings demonstrated that the most virulent strains were A. dhakensis strain 4PS2 and A. hydrophila strain 8TK3, followed by A. dhakensis strain 1P11S3 (the only myo-inositol-utilizing strain), A. veronii strain 6TS5, A. caviae strain 7X11 and the least virulent strain was A. jandaei strain 7KL3 under current disease model. Therefore, more data are needed to assess the influence of myo-inositol utilizing ability on the pathogenesis of Aeromonas spp.The genus Aeromonas has been recognised as an important pathogenic species in aquaculture that causes motile Aeromonas septicaemia (MAS) or less severe, chronic infections. This study compares the pathogenicity of the different Aeromonas spp. that were previously isolated from freshwater fish with signs of MAS. A total of 124 isolates of Aeromonas spp. were initially screened for the ability to grow on M9 agar with myo-inositol as a sole carbon source, which is a discriminatory phenotype for the hypervirulent A. hydrophila (vAh) pathotype. Subsequently, LD50 of six selected Aeromonas spp. were determined by intraperitoneal injection of bacterial suspension containing 103, 105, and 107 CFU/mL of the respective Aeromonas sp. to red hybrid tilapias. The kidneys, livers and spleens of infected moribund fish were examined for histopathological changes. The screening revealed that only A. dhakensis 1P11S3 was able to grow using myo-inositol as a sole carbon source, and no vAh strains were identified. The LD50–240h of A. dhakensis 1P11S3 was 107 CFU/mL, while the non-myo-inositol utilizing A. dhakensis 4PS2 and A. hydrophila 8TK3 was lower at 105 CFU/mL. Similarly, tilapia challenged with the myo-inositol A. dhakensis 1P11S3 showed significantly (p < 0.05) less severe signs, gross and histopathological lesions, and a lower mortality rate than the non-myo-inositol A. dhakensis 4PS2 and A. hydrophila 8TK3. These findings suggested that myo-inositol utilizing A. dhakensis 1P11S3 was not a hypervirulent Aeromonas sp. under current experimental disease challenge conditions, and that diverse Aeromonas spp. are of concern in aquaculture farmed freshwater fish. Therefore, future study is warranted on genomic level to further elucidate the influence of myo-inositol utilizing ability on the pathogenesis of Aeromonas spp., since this ability correlates with hypervirulence in A. hydrophila strains.