Introduction Carp oedema virus (CEV) is a relatively understudied poxvirus. It exhibits an affinity for gill and skin epithelial cells. Investigations were conducted into selected aspects of CEV biology, with a focus on determining cell and tissue tropism of CEV, acquiring gene sequences and updating CEV tests in fish tissues. Material and Methods A total of 238 common carp tissue samples from nine aquaculture farms were analysed. The study evaluated the efficacy of intermediate detection of CEV by real-time PCR and in situ hybridisation. The genes encoding protein P4a were sequenced, analysed and aligned in a phylogenetic tree using a molecular evolution model. Results In situ hybridisation revealed the necessity to validate the Centre for Environment, Fisheries and Aquaculture Science protocols for sampling for CEV detection and to use the tissues for which the virus has the highest tropism, namely the skin and kidneys, rather than solely the gills. The level of genetic variability was determined, and it was shown that CEV mutates systematically. The creation of two distinct phylogenetic clades confirms certain strains’ description as Polish isolates. Conclusion Determining the localisation of CEV genetic material in organs and tissues is pivotal for shaping the World Organisation for Animal Health guidelines. The utility of molecular diagnostics has been demonstrated in the skin and kidney of carp, in addition to the gills, impelling their inclusion in diagnostic protocols. The clusters identified in the phylogenetic tree offer valuable insights for developing the current PCR primers. The prevalence of CEV infection in aquaculture, juxtaposed with its notably lower detection in wild fish, underscores the significance of mandatory molecular diagnostic testing for CEV in carp farming.

Herpesviruses are common agents in animals of the aquatic environment. They infect many species of fish but only lead to disease in one or two species. Nevertheless, infected fish without clinical symptoms can actively transfer infectious agents to disease-susceptible species. The aim of the study was to identify and prove the natural presence of different herpesviruses. Material and Methods Koi, Nile tilapia, grass carp, goldfish and crucian carp were infected with a herpesvirus isolate 99% identical to goldfish herpesvirus (GHV) or cyprinid herpesvirus 2 (CyHV-2) obtained from crucian carp. Before and after infection, samples were collected non-lethally at different time points from all five fish species to identify and evaluate the replication of viruses naturally infecting the fish as well as the CyHV-2 experimentally infecting them. Gill swabs and separated leukocytes were subjected to PCR and the results compared. Results These samples yielded DNA of koi herpesvirus (KHV, also referred to as CyHV-3), GHV and a new herpesvirus. While Asian-lineage CyHV-3 DNA was detected in samples from crucian carp and goldfish, CyHV-2 DNA was found in samples from koi and tilapia. A new, hitherto unknown herpesvirus was identified in samples from grass carp, and was confirmed by nested PCR and sequence analysis. The survival rates were 5% for grass carp, 30% for tilapia, 55% for crucian carp, 70% for koi and 100% for goldfish at 20 days post infection. Evolutionary analyses were conducted and five clusters were visible: CyHV-1 (carp pox virus), CyHV-2 with sequences from koi and tilapia, CyHV-3 with sequences from crucian carp and goldfish, probable CyHV-4 from sichel and a newly discovered herpesvirus – CyHV-5 – from grass carp. Conclusion The results obtained with the molecular tools as well as from the animal experiment demonstrated the pluripotency of aquatic herpesviruses to infect different fish species with and without visible clinical signs or mortality.

Although the presence of rotaviruses in pigeon samples has been reported since the 1980s, its importance as an aetiological agent of the “classical” young pigeon disease (YPD) was not proven until 2020, when the Henle–Koch postulates were confirmed for pigeon-type rotavirus A (RVA) genotype G18P(17). Material and Methods From 2011 to 2020, archived liver samples from 117 pigeons submitted by 74 individual lofts were tested for the presence of pigeon-type RVA using a VP6-specific RT-qPCR test. For four positive racing pigeons, a more detailed necropsy and histopathological analysis was performed. Results Indicators of an acute RVA infection were found in 24 out of 117 (20.5%) samples tested, the earliest in 2014. Necropsies of the four selected RVA-positive pigeons showed changes mainly in the liver, spleen and kidneys similar to those described by other researchers. The histopathological examination revealed mainly hyperaemia and necrosis in the liver, as well as mononuclear cell infiltrates in these organs. Conclusion Pigeon-type RVA is also a cause of YPD in Poland and is a serious challenge for racing pigeon breeders and veterinarians, especially during the training and flights of young pigeons.

Introduction: Rabies as a zoonosis threatens public health worldwide. Several thousand people die each year of infections by the rabies virus (RABV). Oral rabies vaccination (ORV) of wildlife was successfully implemented in many European countries and led to rabies being brought under control there. In Poland, ORV was introduced in 1993 using vaccines containing an attenuated strain of the rabies virus. However, attenuated rabies viruses may have residual pathogenicity and cause the disease in target and non-target animals. Material and Methods: A red fox carcass was tested as part of national rabies surveillance, and its brain was screened for RABV infection using two conjugates and a fluorescent antibody test (FAT). The rabies virus was isolated in mouse neuroblastoma cells by rabies tissue culture infection test (RTCIT), and viral RNA was detected by heminested reverse transcriptase PCR (hnRT-PCR) as well as by quantitative real-time RT-PCR (rtRT-qPCR). An amplicon of 600 bp was subjected to Sanger sequencing. To differentiate between vaccine and field RABV strains, PCR-restriction fragment length polymorphism (PCR-RFLP) using the Dra I, Msp I, Nla IV and Mbo II restriction endonucleases was performed. Results: The rabies virus was detected in the fox’s brain using FAT, RTCIT and molecular tests. The PCR-RFLP revealed of vaccine-induced rabies, and full-length genome analysis showed 100% nucleotide sequence identity of the isolate with the reference sequences of Street Alabama Dufferin Bern (SAD Bern) vaccine strains and other vaccine-induced rabies virus isolates detected in animals and deposited in GenBank. Conclusion: We detected vaccine-induced rabies for the first time in Poland in a fox during routine rabies surveillance.

Introduction: The study was conducted to investigate the prevalence and genetic diversity of Chlamydia spp. in poultry in Poland and estimate possible transmission to humans. Material and Methods: Molecular diagnostic methods followed by sequencing and strain isolation were used on cloacal/faecal swabs collected from 182 apparently healthy poultry flocks including chickens, turkeys, ducks, and geese. Serum samples obtained from people exposed (study group) and non-exposed (control group) to birds were tested by complement fixation test to acquire data on Chlamydia spp. antibody level. Results: Overall, 15.9% of the tested flocks were Chlamydiaceae-positive and three Chlamydia spp. were identified. Predominant chlamydial agent found was C. gallinacea occurring in 65.5% of all positive poultry flocks and in 73.0% of positive chicken flocks. The sequences from four chicken flocks were assigned to C. abortus, whereas C. psittaci was confirmed in one duck and one goose flock. The analysis of ompA variable domains revealed at least nine genetic variants of C. gallinacea. Chlamydial antibodies were detected in 19.2% of human serum samples in the study group in comparison with 10.8% in the controls. Conclusion: The obtained results confirm that chlamydiae are common among chicken flocks in Poland with C. gallinacea as a dominant species. Moreover, the presence of C. abortus in chickens is reported here for the first time. Further investigation should focus on possible zoonotic transmission of C. gallinacea and C. abortus as well as potential pathogenic effects on birds’ health and poultry production.

Brucellosis is a zoonotic disease with a high prevalence in humans and farm animals in Turkey. However, data on the genetic diversity of Brucella spp. circulating in Turkey and parts of the Mediterranean region are limited. In the present study, the genetic diversity of 50 B. melitensis isolates from seven regions of Turkey was investigated using multi-locus variable number tandem repeats analysis (MLVA-16). The profiles were compared with 163 B. melitensis isolates recovered from the Mediterranean basin. B. melitensis strains from Turkey contain 46 different genotypes and consist of two main clusters. B. melitensis isolates from Turkey were closely related to isolates from Greece and some Portuguese strains. The same genotypes isolated from different sites show the spread between sites. Therefore, uncontrolled animal movements and the trade of imported animals can be important factors for the spread of brucellosis. The endemic occurrence of B. melitensis in the Mediterranean basin is a result of socio-historical links between Mediterranean countries. Turkish strains belong to the Eastern Mediterranean line. Eradicating brucellosis in countries of the Mediterranean basin with high prevalence is a demanding need to reduce trade barriers and, more importantly, prevent human suffering

The water buffalo (Bubalus bubalis) in Iran represent an important source of meat and milk products with high biological value. Given the importance of water buffalo in Iran and the prevalence of brucellosis as one of the most important zoonotic diseases in this ruminant species, this study summarized available data on history, epidemiology, diagnosis, and control of brucellosis in water buffalo from previous studies that have been carried out in Iran. According to the documented data, there are three main groups of Iranian buffalo, including the Khuzestan ecotype (Khuzestan province); the Azary ecotype (Western/ Eastern Azarbaijan and Ardabil provinces); and the North ecotype (Gylan and Mazandaran provinces). Preliminary studies conducted on Iranian buffaloes either by serological or molecular tools reported that buffaloes' infection occurred due to natural exposure to a wild strain of Brucella abortus and Brucella melitensis. Previous studies dealing with brucellosis in Iranian buffalo are next to none. This review notifies the importance of reliable and detailed epidemiological investigations of Iranian buffaloes through continuous monitoring systems of the health status of buffalo populations. Continuous test and slaughter strategy, vaccination, and re-planning of veterinary activities are required to mitigate buffalo's role in disseminating and maintaining brucellosis in Iran.

From brain samples collected from domestic animals in Ethiopia, two rabies-related viruses were isolated. According to their reactivity pattern with anti-nucleocapsid monoclonal antibodies, they were characterized as Lagos bat virus (isolate Eth-58) and Mokola virus (isolate Eth-16). This classification was confirmed by neutralization experiments with Mokola and Lagos bat specific antisera. Two potent anti-rabies vaccines were unable to protect mice against the two rabies-related viruses. In order to investigate molecular relationships to classical rabies virus, cDNA cloning and sequencing was performed. The RNA genome of both viruses comprises 12 kilobases (kb) and has an organization similar to that of rabies virus with the gene order 3'-N-P-M-G-L-5'. Using virus-specific cDNA as probes in heterologous hybridization experiments, the RNAs of other members of lyssavirus serotypes 2 and 3 were detected. From hybridization experiments and sequence analysis of the 3' terminal 5,5 kb of the genomes, Eth-16 and Eth-58 viruses were shown to be equally genetically distant from rabies virus with 60% nucleotide identity; Eth-16 and Eth-58 had 68% homology.

Brucellosis is a serious disease that affects both animals and humans. It is caused by consuming unpasteurized dairy products that are contaminated with the Brucella bacteria. To study the pathobiology of this disease and develop preventive strategies, researchers rely on in vivo and in vitro models. A systematic literature search was conducted in January 2024, which revealed 38 studies that used these models in the previous four years. Mice were the most commonly used model for studying the disease's virulence genes, immune responses, vaccination, and treatment testing. Out of the 38 articles discussing infection models in brucellae, 6 used only in vivo models, 9 used only in vitro models, and 24 used both models. In addition, there were 32 studies with in vitro experiments, most of which utilized macrophages to study intracellular survival mechanisms and host-pathogen interactions. The studies mainly focused on B. abortus, as it had a significant impact on public and livestock health. Both in vivo and in vitro models were used to understand comprehensive intracellular mechanisms, immune responses, and treatment evaluations. However, there were several challenges in using these models, such as ethical concerns and host pathogen-specific immune responses. While both models provided important insights, the final selection choice of the model mostly depended on the research objectives, pathogen type, and availability of resources. Nevertheless, validation and understanding of these models are important to predict responses in the natural hosts