First isolation and molecular characterization of canine parvovirus-type 2b (CPV-2b) from red foxes (Vulpes vulpes) living in the wild habitat of Turkey

BACKGROUND

The canine parvovirus, with its many variants, is responsible for a pivotal and common viral infection affecting millions of dogs and other carnivore species worldwide, particularly the wild ones, which are considered as the main reservoir hosts. To that end, this study investigated the presence of canine parvovirus (CPV) in red foxes (Vulpes vulpes) living in wild habitats of several regions of Turkey.

METHODS

We randomly collected 630 archival fox stool specimens from rural areas of 22 provinces and used real-time PCR to detect CPV.

RESULTS

Two of the 630 (0.3%) stool samples were positive for CPV-DNA, named Tr-Fox/128(Aydın) and Tr-Fox/159(Manisa). We attempted to isolate the virus in a MDCK cell line, and cytopathic effects were observed four days post-inoculation. Three regions corresponding to the CPV capsid protein VP2 gene from extracted DNA of positive samples were amplified by conventional PCR, and the products were visualised, purified, and Sanger sequenced. Three overlapping DNA raw sequence fragments, were read, assembled, and aligned to obtain approximately 1.5 kb-long regions that cover most of the VP2 gene, then deposited in GenBank. After comparing the isolates with parvovirus sequences data of domestic and wild carnivores by BLAST processing, our isolates' similarity rate with each other was 99.40%, with base differences in 9 nucleotide positions. They were classified as 2b variant closely related to isolates from dogs in Turkey, Egypt, Iraq, Italy, Thailand, and China.

CONCLUSION

This study presents evidence of interspecies transmission of CPV, of which there are no reports on prevalence in wildlife carnivores of our country. Identification of CPV in red foxes threatens local and hunting dogs, which may contract the infection or disseminate it to other wild animal species or vice-versa.

Development of a recombinase polymerase amplification assay for viral haemorrhagic septicemia virus

Viral diseases of fish cause significant economic losses in the aquaculture industry. Viral haemorrhagic septicemia virus (VHSV) is one of the most important viral diseases that affects more than 80 fish species. Detection of the disease, especially in the field, is critical to managing disease prevention and control programmes. Recombinase polymerase amplification (RPA) is an isothermal method with a very short amplification period and a single incubation temperature ranging from 37 to 42°C, which is a good alternative to the polymerase chain reaction (PCR). This study aimed to develop an RPA assay as sensitive as a real-time RT-PCR to detect VHSV. For this purpose, primers and probes are designed for the same targeted region of gG of VHSV. The ssRNA standards were prepared to find the detection limits of the assay. Detection limits were found ten-fold differences between real-time RT-PCR and real-time RT-RPA. While the detection limit of the RT-PCR was found as 95.5 viral RNA molecules/reaction in 95% probit value, the detection limit of RT-RPA was found as 943.75 viral RNA molecules/reaction in 95% probit value using ssRNA standards. These results show that RPA is a suitable test for VHSV Ie detection.

Sentinel serosurveillance of backyard hens proved West Nile virus circulation in the western provinces of Turkey

West Nile virus (WNV) is a mosquito-borne virus of a re-emergence importance with a wide range of vertebrate hosts. Granted, it causes asymptomatic infection, but fatal cases and neurologic disorders were also recorded, especially in humans, horses and some exposed birds. The virus is globally spread and birds are considered an amplifying and reservoir host of WNV, helping to spread the disease due to their close contact with main hosts. In this study, we aimed to detect the presence of antibodies against WNV in backyard hens that were reared in the western Anatolian part of Turkey. A total of 480 chicken sera were randomly collected from six provinces in the west of Turkey (Mugla, Izmir, Aydin, Afyonkarahisar, Kutahya and Manisa) with 80 samples from each province (40 in spring and 40 in fall seasons). They were tested by using a competitive ELISA method to identify the specific avian antibodies of IgG that produced against the WNV envelope proteins (pr-E). Twelve of 480 (2.5%) sera were found seropositive, three of these positive sera were detected from the Izmir province (3.75%) collected in the spring session and the other nine positive sera were detected from the Mugla province (11.25%) collected in the fall session. Both of these provinces are located seaside and have suitable climate conditions for vectors of infection. The results indicated that WNV infection is in circulation in these provinces, and that may put the other susceptible vertebrates under risk of infection.

A serosurvey for bovine respirovirus 3 in Turkish domestic ruminants: The first comparison study of A and C genotypes

Bovine parainfluenza virus‐3 (BPIV‐3), also known as bovine respirovirus 3, causes serious respiratory infection in ungulates, often involving other pathogens, such as viruses, bacteria and mycoplasmas. In this study, we evaluated antibody titers against virus genotypes A (BPIV‐3a) and C (BPIV‐3c). We conducted a serological survey and comparison analysis of archived serum samples from small and large ruminants reared in four Turkish provinces. A total of 1,307 samples, consisting of sheep (n = 444), cattle (n = 402), water buffalo (n = 261) and goat (n = 200) sera, were randomly selected from stock samples collected between 2015 and 2019 and screened by standard virus neutralisation assay. We found that 49.9% (653/1307) of all samples were positive for neutralising antibody titers. Goats had the highest titer, with total seropositivity of 63% (126/200), followed in descending order by cattle, sheep and water buffalo at 56.2% (226/402), 32.2% (143/444) and 26% (68/261) total seropositivity, respectively. BPIV‐3c had the highest neutralising antibody rate at 34.3% (448/1307), whereas BPIV‐3a had a 24.3% (317/1307) seropositivity rate. Neutralising antibody titers for positive samples ranged between 1/4 and 1/512 per the SN₅₀ test. Seropositivity rates ranged from a low of 8.9% to a high of 18.3%. Our study was the first to compare antibody seroprevalence for two BPIV‐3 genotypes in small and large domestic ruminants, which were shown to be more commonly exposed to BPIV‐3c than BPIV‐3a. This finding could have significant implications as current vaccines mainly use the BPIV‐3a genotype. Further research can determine if current vaccines protect against different BPIV‐3 virus genotypes.

Marek's disease virus in vaccinated poultry flocks in Turkey: its first isolation with molecular characterization

Marek's disease (MD) is an important disease of avian species and a potential threat to the poultry industry worldwide. In this study, 16 dead commercial chickens from flocks with suspected MD were necropsied immediately after death. Pathological findings were compatible with MD, and gallid alphaherpesvirus 2 was identified in PCR of spleen samples. Virus isolation was performed in primary cell culture, and partial sequencing of the meq gene of the isolate revealed >99% nucleotide sequence identity to virulent and very virulent plus strains from a number of European countries, placing it in the same subclade of clade III as two virulent Italian strains and a very virulent plus Polish strain as well as virulent strains of geese and ducks. The data reported here indicate that a virulent strain of Marek's disease virus is circulating in Turkey and has not been stopped by the current national vaccination programme.

Circulation of Indigenous Bovine Respiratory Syncytial Virus Strains in Turkish Cattle: The First Isolation and Molecular Characterization

Bovine respiratory disease (BRD) is a huge economic burden on the livestock industries of countries worldwide. Bovine respiratory syncytial virus (BRSV) is one of the most important pathogens that contributes to BRD. In this study, we report the identification and first isolation, with molecular characterization, of a new BRSV strain from lung specimens of three beef cows in Turkey that died from respiratory distress. After the screening of lung tissues for BRD-associated viruses using a multiscreen antigen-ELISA, a BRSV antigen was detected. This was then confirmed by real-time RT-PCR specific for BRSV. Following confirmation, virus isolation was conducted in MDBK cell cultures and clear CPE, including syncytia compatible with BRSV, were detected. RT-nested PCR, using F gene-specific primers, was performed on the cultured isolates, and the products were sequenced and deposited to Genbank with accession numbers MT179304, MT024766, and MT0244767. Phylogenetic analysis of these sequences indicated that the cattle were infected with BRSV from subgroup III and were closely related to previously identified American and Turkish strains, but contained some amino acid and nucleotide differences. This research paves the way for further studies on the molecular characteristics of natural BRSV isolates, including full genome analysis and disease pathogenesis, and also contributes to the development of robust national strategies against this virus.