Susceptibility of Mediterranean Buffalo (Bubalus bubalis) following Experimental Infection with Lumpy Skin Disease Virus.

Lumpy skin disease (LSD) is a viral disease of cattle and water buffalo characterized by cutaneous nodules, biphasic fever, and lymphadenitis. LSD is endemic in Africa and the Middle East but has spread to different Asian countries in recent years. The disease is well characterized in cattle while little is known about the disease in buffaloes in which no experimental studies have been conducted. Six buffaloes and two cattle were inoculated with an Albanian LSD virus (LSDV) field strain and clinically monitored for 42 days. Only two buffaloes showed fever, skin nodules, and lymphadenitis. All samples collected (blood, swabs, biopsies, and organs) were tested in real-time PCR and were negative. Between day 39 and day 42 after inoculation, anti-LSDV antibodies were detected in three buffaloes by ELISA, but all sera were negative by virus neutralization test (VNT). Cattle showed severe clinical signs, viremia, virus shedding proven by positive real-time PCR results, and seroconversion confirmed by both ELISA and VNT. Clinical findings suggest that susceptibility in buffaloes is limited compared to in cattle once experimentally infected with LSDV. Virological results support the hypothesis of buffalo resistance to LSD and its role as an accidental non-adapted host. This study highlights that the sensitivity of ELISA and VNT may differ between animal species and further studies are needed to investigate the epidemiological role of water buffalo.

Tick Species Diversity and Molecular Identification of Spotted Fever Group Rickettsiae Collected from Migratory Birds Arriving from Africa.

The role of migratory birds in the spread of ticks and tick-borne pathogens along their routes from Africa to Europe is increasingly emerging. Wild birds can host several tick species, often infected by bacteria responsible for zoonoses. The aim of the study is to assess the possible introduction of exotic ticks carried by migratory birds into Italy from Africa and to detect the presence of Rickettsia species and Coxiella burnetii they may harbor. During a two-year survey, we collected ticks from migratory birds captured during their short stop-over on Ventotene Island. Specimens were first identified by morphology or sequencing molecular targets when needed, and then tested by real-time PCR for the presence of selected pathogens. A total of 91% of the collection consisted of sub-Saharan ticks, more than 50% of which were infected by Rickettsia species belonging to the spotted fever group, mainly represented by R. aeschlimannii. In contrast, the suspected C. burnetii detected in two soft ticks were confirmed as Coxiella-like endosymbionts and not the pathogen. Although there are still gaps in the knowledge of this dispersal process, our findings confirm the role of migratory birds in the spread of ticks and tick-borne pathogens, suggesting the need for a continuous surveillance to monitor the potential emergence of new diseases in Europe.

Direct and Indirect Role of Migratory Birds in Spreading CCHFV and WNV: A Multidisciplinary Study on Three Stop-Over Islands in Italy.

The annual movements of migratory birds can contribute to the spread of African ticks and tick-borne pathogens of potential public health concern across Europe. The aim of the study was to investigate their role in the possible introduction of African ticks and tick-borne pathogens into European countries during spring migration. A total of 2344 ticks were collected during three spring seasons from 1079 birds captured on three Italian stop-over islands during their northbound migration. Once identified, each tick was tested by RT-PCR for the presence of Crimean-Congo hemorrhagic fever (CCHFV), West Nile (WNV), and Usutu (USUV) viruses. Moreover, carcasses of birds found dead were collected and tested for the possible presence of WNV and USUV. Results confirmed a higher contribution of trans-Saharan migrants compared to intra-Palearctic ones and the prevalence of African tick species in the sample. CCHFV was detected for the second time in Italy in a Hyalomma rufipes, and WNV was found in two ticks of the same genus, all carried by trans-Saharan birds. WNV lineage 1 was also found in the organs of a Garden warbler. These results confirm the role of migratory birds in carrying African ticks, as well as viruses of zoonotic importance, from Africa into Europe.

West Nile and Usutu Virus Introduction via Migratory Birds: A Retrospective Analysis in Italy.

The actual contribution of migratory birds in spreading West Nile (WNV) and Usutu virus (USUV) across Europe and from Africa to old countries is still controversial. In this study, we reported the results of molecular and serological surveys on migrating birds sampled during peaks of spring and autumn migration at 11 Italian sites located along important flyways, from 2012 to 2014. A total of 1335 specimens made of individual or pooled sera, and organs from 275 dead birds were tested for WNV and USUV RNA by real time PCR (RT-PCR). Furthermore, sera were tested by serum neutralization assay for detecting WNV and USUV neutralizing antibodies. Molecular tests detected WNV lineage 2 RNA in a pool made of three Song Thrush (Turdus philomelos) sera sampled in autumn, and lineage 1 in kidneys of six trans-Saharan birds sampled in spring. Neutralizing antibodies against WNV and USUV were found in 5.80% (n = 72; 17 bird species) and 0.32% (n = 4; 4 bird species) of the tested sera, respectively. Our results do not exclude the role of migratory birds as potential spreaders of WNV and USUV from Africa and Central Europe to Mediterranean areas and highlight the importance of a more extensive active surveillance of zoonotic viruses.

Neutralization of SARS-CoV-2 Variants by Serum from BNT162b2 Vaccine Recipients.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has evolved rapidly, leading to viral lineages characterized by multiple mutations in the spike protein, which could potentially confer to the virus the ability to avoid the vaccine-induced immune response, making the vaccines less effective or ineffective. Here, we initially evaluated the neutralization capabilities in vitro by serum neutralization (SN) of six serum samples collected from recipients of the BNT162b2 vaccine against 11 SARS-CoV-2 isolates belonging to the major SARS-CoV-2 lineages that had been circulating in Italy. Then, we considered 30 additional serum samples by SN assay against the dominant B.1.617.2 (Delta) variant. A B.1 lineage isolate was used as a reference. In the first analysis, significant differences when compared with the reference strain (p > 0.05) were not evidenced; instead, when the panel of 30 sera was tested against the B.1.617.2 (Delta) variant, a significant (p = 0.0015) 2.38-fold reduction in neutralizing titres compared with the reference after the first vaccine dose was demonstrated. After the second vaccine dose, the reduction was not significant (p = 0.1835). This study highlights that the BNT162b2 vaccine stimulates a humoral response able to neutralize all tested SARS-CoV-2 variants, thus suggesting a prominent role in mitigating the impact of the SARS-CoV-2 pandemic in real-world conditions. Long-term follow-up is currently ongoing.

Assessing the role of migratory birds in the introduction of ticks and tick-borne pathogens from African countries: An Italian experience.

The continuous flow of billions of birds between Africa and Europe creates an "ecological bridge" between physically remote areas. Migratory birds fly south from their breeding grounds during late summer/fall and fly back in spring. These movements regulate the spread of internal and external parasites, as well as pathogens of potential public health concern. The aim of the present study was to investigate the possible introduction of exotic tick species and tick-borne pathogens into Europe via migratory birds. At the bird observatory of Ventotene island (Italy), 443 feeding ticks were collected from 249 birds captured and ringed during their northbound migration in spring 2013. Each tick was identified by morphological and molecular methods and then tested for bacterial and viral pathogens: Borrelia burgdorferi s.l., Rickettsia spp., Ehrlichia ruminantium and Coxiella burnetii, Crimean Congo haemorrhagic fever virus (CCHFV) and Flavivirus. Morphological and molecular identification confirmed Hyalomma rufipes as the most abundant species among the collected arthropods (366/443; 82.6%) followed by Hyalomma marginatum (10/433; 2.3%). Rickettsia aeschlimannii was identified in 158 ticks, while one engorged Amblyomma variegatum nymph was infected with Rickettsia africae. The other bacteria were not detected in any specimen. Among viruses, RNA belonging to West Nile virus and other Flavivirus were detected whereas all ticks were negative for CCHFV RNA. These results confirm how migratory birds play a role in carrying Rickettsia-infected ticks, as well as viruses of zoonotic importance, from Africa into Europe. To what extent tick species are capable of establishing a permanent population once introduced in naïve areas, is far from defined and deserve further investigation.

Crimean-Congo Hemorrhagic Fever Virus Genome in Tick from Migratory Bird, Italy.

We detected Crimean-Congo hemorrhagic fever virus in a Hyalomma rufipes nymph collected from a whinchat (Saxicola rubetra) on the island of Ventotene in April 2017. Partial genome sequences suggest the virus originated in Africa. Detection of the genome of this virus in Italy confirms its potential dispersion through migratory birds.

Dietary flavonoids advance timing of moult but do not affect redox status of juvenile blackbirds (Turdus merula).

Flavonoids are the most abundant plant polyphenols, widely occurring in fruits and berries, and show a strong antioxidant activity in vitro Studies of avian species feeding on berries suggest that dietary flavonoids have health-promoting effects and may enhance the expression of melanin-based plumage traits. These effects are probably mediated by the antioxidant activity of flavonoids. However, the effect of dietary flavonoids on oxidative status has never been investigated in any bird species. We analysed the effects of dietary flavonoids on blood non-enzymatic antioxidants and protein oxidative damage of juvenile European blackbirds (Turdus merula). In addition, we analysed the effects of flavonoid-enriched diet on body condition and on the timing of moult from juvenile to adult plumage. Dietary flavonoids did not significantly affect redox status but significantly advanced the onset of moult, hastening plumage development. Moulting birds showed higher protein oxidative damage compared with those that had not yet started moulting. The probability of initiating moult after 40 days of dietary treatment was higher for birds with low circulating levels of oxidizing agents and high glutathione concentration. The metabolization of flavonoids could have altered their redox potential, resulting in no net effects on redox status. However, flavonoid consumption before and during moult may contribute to enhance plumage development. Moreover, our findings suggest that moulting feathers may result in redox imbalance. Given their effect on moult and growth of melanin-rich feathers, fruit flavonoids may have contributed to shape plant fruiting time in relation to fruit consumption preferences by birds.