Veterinary Medicine International最新文献

Bovine viral diarrhea (BVD) is a significant economic concern due to the risk of persistent infection and complex epidemiology in cattle-producing countries, including Ethiopia. This study aimed to identify the circulating BVD virus type in dairy cattle, investigate seroprevalence, and assess associated risk factors in Jimma town, Oromia regional state, Southwestern Ethiopia. A cross-sectional study was conducted from November 2023 to April 2024, involving 48 randomly selected dairy farms out of 130 registered ones. In total, 383 serum samples from BVD virus (BVDV) nonvaccinated animals were tested for BVD virus antibodies and antigens using a competitive enzyme-linked immunosorbent assay (ELISA) kit (ID Screen BVD p80 antibody). Additionally, a one-step reverse transcription polymerase chain reaction (RT-PCR) was used to detect the viral genome in pooled swab samples. Analytical statistics, including chi-square and multivariable logistic regression, were employed for data analysis using SPSS, Version 26. The study revealed that 72 animals (18.8%) and 20 farms (41.7%) tested positive for BVDV antibodies. All the tested samples were negative for BVDV antigen and viral genome. Age, history of respiratory problems, breeding system, and housing system were statistically associated with seroprevalence (p < 0.05). At the farm level, only the production system showed a significant association (p < 0.05). Adult animals had 2.2 times the odds of being seropositive (OR = 2.2; p = 0.02). Animals with respiratory issues and those housed in head-to-tail arrangements had 2.7 (p = 0.205) and 4.8 (p = 0.021) times the odds of being seropositive, respectively. In conclusion, a substantial proportion of dairy cattle in the study area are exposed to BVD virus. However, no evidence of persistent infection was found among the dairy farms. Effective management strategies are crucial, including vaccination, biosecurity measures, and housing management.

Paratuberculosis (PTB) is a disease affecting ruminant animals. The etiological agent, Mycobacterium avium subspecies PTB (Map), is a short, Gram-positive, acid-fast bacillus. Due to the nature of PTB, diagnosis often occurs at advanced stages of the disease, following the onset of clinical symptoms and prior dissemination of the agent. The specificity of current humoral diagnostic techniques, such as ELISA, is limited, mainly due to the presence of various species of mycobacteria in the environment and other closely related pathogenic mycobacteria that can interfere with the accurate diagnosis of PTB due to the high rate of gene conservation within the genus. In the present study, we evaluated the effectiveness and specificity of an ELISA based on a Map polyprotein for diagnosing bovine PTB. The efficacy of the polyprotein-based ELISA was assessed using serum samples from healthy, Map-infected, and Mycobacterium bovis (MB)-infected cattle. Specificity was further evaluated using serum samples from healthy and MB-infected wild animals. Our findings revealed that in most cases, the degree of cross-reactivity was negligible or low, particularly in cattle, swine, and goats, while it ranged between 10% and 12.5% in sheep and cervids, respectively. These results suggest that the Map polyprotein used in the ELISA represents a valuable tool for the specific diagnosis of PTB in herds.

Schmallenberg virus (SBV) is endemic in Europe and other parts of the world and represents an underestimated and underdiagnosed cause of abortion and economic losses for livestock farms. In the present study, we evaluated SBV's impact on three ruminant farms, in particular, two dairy cattle farms with reproductive problems (including abortions, stillbirths, and malformations) and a clinically healthy buffalo farm involved in oocyte collection through ovum pick-up (OPU) for in vitro embryo production and commercial sale. All sampled animals were subjected to serological assays against the main infectious agents responsible for reproductive disorders in ruminants: SBV, bluetongue virus (BTV), Coxiella burnetii (C. burnetii), bovine herpesvirus type 1 (BHV-1), bovine viral diarrhea virus (BVDV), and Brucella abortus (B. abortus). The first herd with reproductive disorders had a high (78%) seroprevalence for SBV (considered to be the cause of reproductive problems), while the prevalence observed for BTV was modest (16.7%). Although free from B. abortus, the second dairy farm had only a few animals that were seropositive for C. burnetii and BTV (1/22 and 2/22, respectively), but a prevalence of 72.7% for SBV. The buffalo farm had several animals seropositive for C. burnetii (9/52), BTV (10/52), and SBV (12/52). Almost half of the sampled animals were exposed to at least one pathogen (26/52). Seropositive animals were excluded from oocyte collection in compliance with regulatory health requirements. One month later, seronegative animals were retested, revealing the seroconversion of another animal for SBV, which was also excluded. This study has described, through seroprevalence testing, the direct impact of SBV on livestock (clinical impact) and how it affects the selection of animals for the trade of genetic material (indirect impact).

Epizootic haemorrhagic disease (EHD) is a viral noncontagious arthropod-borne disease transmitted by blood-sucking midges of the genus Culicoides. Its causative agent, the EHD virus (EHDV), belongs to the genus Orbivirus and is responsible for domestic and wildlife ruminants' disease outbreaks, especially in North America, Asia, Africa and Oceania. These outbreaks not only cause significant morbidity and mortality but also have welfare, social and economic implications. Recently, EHD has become a real threat to the European Union, with outbreaks confirmed in October and November 2022 in Sardinia and Sicily. To better understand this phenomenon, we investigated the drivers of the observed increasing EHD incidence in Europe through expert knowledge elicitation. We listed 51 possible drivers grouped in eight domains and elicited 41 European experts to (i) allocate a score per driver, (ii) weight this score within each domain and (iii) weight the different domains and attribute an uncertainty level for each. An overall weighted score per driver was calculated, and drivers with comparable scores were grouped in four distinct terminal nodes using a regression tree analysis. The four drivers included in a terminal node with the highest scores were (i) the influence of temperature on the abundance or survival of vector populations; the legal or illegal movements of live animals from (ii) third countries or (iii) from neighbouring countries of Europe and the European Union; and (iv) the current unavailability of vaccines against Circulating Serotype 8. Our results support researchers in prioritizing studies targeting the most relevant drivers of the observed spread of EHD in animals in Europe. In addition, some strategic lines in terms of research and action are depicted.

The Ecuadorian highlands provide favourable climate conditions for bovine milk production, where small- and medium-sized farms represent over 80% of dairy producers. However, in communities with limited technological resources, both clinical (CM) and subclinical mastitis (SM) pose significant challenges to productivity. This study surveyed a dairy-producing community in the central Ecuadorian highlands to evaluate risk factors associated with bovine mastitis and to analyse milk quality parameters. The prevalence of SM and CM at the animal level was 34.8% (130/374) and 1.9% (7/374), respectively, and at the farm level, it was 34.1% (29/85) for SM and 7.0% (6/85) for CM. Univariate and multivariable logistic regression models were used to identify factors associated with the presence of SM and CM. An associated factor with the presence of SM (p < 0.05) was the non-compliance with time medication withdrawal (odds ratio [OR] = 3.88; 95% CI: 1.31-13.0). In contrast, performing the California mastitis test was a protective factor (OR = 0.32; 95% CI: 0.10-0.93). At animal level, the use of crossbreeds increased the probability of SM (OR = 2.64; 95% CI: 1.58-4.41). The presence of SM in the herd significantly increased the risk of CM (OR = 12.47; 95% CI: 1.30-119.31). Milk samples positive for mastitis showed changes in density, added water, and freezing point. These findings highlight the need for farmer training and strict adherence to diagnostic and preventive protocols for bovine mastitis in order to improve herd health and milk quality.

Infectious diarrhea is one of the most serious health threats to camel calves, causing death and substantial loss. This study aimed to determine the prevalence of bacterial pathogens causing diarrhea in camel calves and identify the associated risk factors in the Shabeley and Kebribayah Districts of the Fafan zone, Eastern Ethiopia. A cross-sectional study was conducted from March 2022 to January 2023 to isolate and identify bacteriological infections of camel calf diarrhea and their associated risk factors in selected districts of the Fafen zone of the Somali region, Eastern Ethiopia. In total, 384 fecal swabs were collected from diarrheal, convalescent, and healthy camel calves. Using pure culture and bacteriological isolation, the overall prevalence of a bacterial infection was 66 (17.2%; 95% Cl: 0.13-0.21). Similarly, the distribution of the identified bacterial species was as follows: Escherichia coli (58%), Salmonella spp. (30%), and Enterococcus spp. (12%). The prevalence of camel calf infections in Kebribayah (9.0%) was higher than that in Shabeley (8.3%). Similarly, calves aged 7-12 months and diarrheal calves showed higher infection rates (7.6% and 8.6%, respectively). However, younger calves aged 0-3 months and apparently healthy calves had the lowest prevalence (4.7% and 3.4%, respectively). In the univariate logistic regression analysis, calves aged 7-12 months and calves with diarrhea showed statistically significant differences (p < 0.05). Furthermore, the incidence of diarrhea in camel calves was statistically significant (p > 0.05) in the multivariable logistic analysis. However, convalescent calves (OR = 1.79, 95% Cl: 0.38-1.64) were 1.79 times more likely to be infected with bacterial species than apparently healthy camel calves. This study indicated the presence of enteric bacteria in the study areas; therefore, further epidemiological investigations on other species of enteric bacteria and the implementation of public health education are warranted.

The role of testosterone in regulating the antler cycle and sexual behavior in temperate cervids is well documented. However, studies on tropical cervids, such as the sambar deer (Rusa unicolor), remain limited. This study aimed to measure testosterone levels and investigate their relationship with sexual behavior across different antler stages using a noninvasive approach. Eight sambar deer stags aged 3-5 years, housed in the Taman Rusa Zoo, Aceh, Indonesia, were observed. Fecal samples were collected 1-3 times per week from each individual, along with the behavior observation and antler stage assessments. Sexual behaviors were carried out using focal animal sampling and recorded using the all-occurrence sampling method. Levels of testosterone in feces were measured using the enzyme-linked immunosorbent assay technique. Data were analyzed using a linear mixed-effects model with antler stage as a fixed effect and individual identity as a random factor. Spearman's rank correlation test was used to examine the relationship between testosterone levels and sexual behavior. The results revealed a clear association between testosterone levels, antler stages, and male sexual behaviors. Levels of testosterone varied significantly among antler stages, with higher levels found during the hard and velvet stages compared to the casting stage (p < 0.01). Moreover, a strong positive correlation was found between testosterone levels and male sexual behavior during the hard antler stage (rs = 0.763, p < 0.01). Despite high testosterone levels during the velvet stage, male sexual behaviors, such as anogenital sniffing, anogenital licking, and flehmen, were significantly lower compared to the hard antler stage. These results suggest that testosterone may play additional roles beyond those related to male competition or mating during the velvet stage, which warrants further investigation. Understanding the dynamics of testosterone and male sexual behavior is crucial for the effective management and conservation of sambar deer populations in captivity.

Background: Reproductive efficiency is a key economic trait in sheep production, with litter size being a major determinant of productivity. Genetic polymorphisms in candidate genes such as BRCA1, PPAP2B, and KCNN3 may influence fecundity, but their association with sheep prolificacy remains to be fully elucidated. Identifying genetic markers linked to high litter size could enhance breeding strategies for improved reproductive performance.

Objective: This study aimed to (1) investigate the relationship between BRCA1, PPAP2B, and KCNN3 gene polymorphisms and sheep litter size and (2) identify potential genetic markers for high fecundity in sheep.

Methods: Whole-genome resequencing combined with Sequenom MassARRAY SNP genotyping was used to analyze five polymorphic loci in BRCA1, PPAP2B, and KCNN3 across five sheep breeds, including high-prolificacy breeds (Small-Tailed Han sheep, Hu Sheep, and Cele Black Sheep) and low-prolificacy breeds (Sunite sheep and Bamei mutton sheep). Small-Tailed Han sheep were selected for association analysis with litter size. Chi-square tests assessed Hardy-Weinberg equilibrium (HWE), and association studies evaluated genotype effects on reproductive traits.

Results: BRCA1 gene polymorphisms (g.42581575 T > C, g.42560830 A > T, g.42548851 C > T) exhibited significant differences (p < 0.01) in genotype and allele frequencies between high- and low-prolificacy breeds. All three loci were in HWE (p > 0.05) except in Hu sheep. The KCNN3 g.103522805 C > A locus also showed significant frequency differences (p < 0.01) between breeds but deviated from HWE in Bamei mutton sheep (p < 0.05).Only the PPAP2B g.77092130 G> A locus demonstrated a significant association (p > 0.05) with litter size in Small-Tailed Han sheep, where the GG genotype was more frequent than the AA genotype in the second parity.

Conclusion: This study identified BRCA1, PPAP2B, and KCNN3 as potential genetic markers influencing sheep litter size. The BRCA1 and KCNN3 polymorphisms showed strong breed-specific associations, while the PPAP2B GG genotype may favor higher fecundity in Small-Tailed Han sheep. These findings provide valuable insights for marker-assisted selection in sheep breeding programs aimed at improving reproductive efficiency. Further functional studies are needed to validate the biological mechanisms underlying these genetic associations.

Background: The ocular microbiome of cats infected with feline immunodeficiency virus (FIV) or feline leukemia virus (FeLV) might differ from that of healthy cats. This study aimed to examine and compare the conjunctival bacterial and fungal flora in these groups.

Methods: Bacterial and fungal cultures were conducted from the conjunctiva of 80 Persian cats, categorized into four groups: normal, FIV-infected, FeLV-infected, and co-infected with both FIV and FeLV. PCR assays confirmed the presence of FIV, FeLV, Chlamydia, and Mycoplasma. The microbiological analysis was compared across the different.

Results: The conjunctival bacterial flora of normal cats was predominantly Gram-positive, with Staphylococcus species as the most common isolates. Escherichia coli was absent in the normal group but present in all infected groups, with the highest prevalence in the co-infected group (17.5%). Co-infection with FIV and FeLV led to a distinct microbiota with Streptococcus agalactiae, Corynebacterium renale, Fusarium, and Aspergillus brasiliensis exclusively found in this group.

Conclusions: The co-infection of FIV and FeLV significantly alters the conjunctival microbiome, promoting the colonization of specific opportunistic pathogens. These findings may influence the clinical management of cats with these viral infections, especially in combination, and may create a more favorable environment for the growth of certain bacteria and fungi in the conjunctiva.

Background and aims: Circovirus parrot and Gammapolyomavirus avis are two clinically important viruses affecting psittacine birds. Although several studies have investigated their genomic variability, pathogenesis and associated pathological features individually, understanding of the effects and pathogenesis of Circovirus parrot and Gammapolyomavirus avis coinfection remains limited. This study was designed to investigate the molecular characteristics of Circovirus parrot and Gammapolyomavirus avis, tissue distribution of the viruses and histopathology during the course of the disease in naturally infected birds.

Methods: A total of 16 Circovirus parrot and Gammapolyomavirus avis polymerase chain reaction (PCR)-positive budgerigars (Melopsittacus undulatus) were euthanised, including six without clinical signs and 10 with clinical signs. Ten types of tissue samples were screened using real-time PCR to detect viruses. Molecular characterisation of the viruses was determined using partial genome sequencing. Additionally, histopathological examination was performed to investigate cellular changes.

Results: Viral distribution varied significantly between tissues (p < 0.001) with proportionately higher detection rates in bone marrow (16/16, 100%), cloacal swab (16/16, 100%), feather (15/16, 93.75%) and oral swab (16/16, 100%) for Circovirus parrot and in bone marrow (16/16, 100%) and feather (9/16, 56.25%) for Gammapolyomavirus avis, than in other tissue types. No significant variation was observed in detection rate between birds with and without clinical signs for both Circovirus parrot (p = 0.86) and Gammapolyomavirus avis (p = 0.55). Cellular necrosis and degenerative changes were observed in different tissues, with or without the presence of viral DNA. Molecular analysis suggests that the Circovirus parrot circulating in Bangladesh may represent a unique genotype and shares an ancestral relationship with currently circulating strains, whereas Gammapolyomavirus avis appears to be less diverse and shares an ancestral relationship with both local and global isolates.

Conclusion: Findings of this study will be useful in understanding the molecular aspects of pathogenesis and disease epidemiology, thus aiding in the design of effective control measures of these diseases.