The quail may be the unknown reservoir of Tuscany virus (TOSV) and Sicilian sandfly fever virus (SFSV), mosquito-borne pathogens that can infect domestic animals and also cause disease in humans. This conclusion emerges from a study published in the journal frontiers in microbiologyand which will be led by Jordi Serra-Cobo, Professor at the Faculty of Biology and the Institute for Biodiversity Research (IRBio) at the University of Barcelona, and Remi Charrel from the University of Aix-Marseille (France).
This is the first time researchers have found neutralizing antibodies against TOSV and SFSV in wild birds. “Until now, the reservoir for these two viruses was unknown, although they have been sought for years. Dogs and bats were suggested as reservoirs, but the results showed that neither was the case,” says Jordi Serra-Cobo, an expert in epidemiological studies using bats as natural reservoirs of infectious agents such as coronaviruses.
The study, whose first author is Nazli Ayhan from the University of Aix-Marseille, involves José Domingo Rodríguez Teijeiro, Marc López-Roig, Dolors Vinyoles and Abir Monastiri (UB Faculty of Biology and IRBio) and Josep Anton Ferreres (UB Faculty of Biology ).
Emerging viruses in the Mediterranean
TOSV and SFSV are among those phlebovirus Genus and are considered emerging pathogens. They are spherical, single-stranded RNA viruses with a high mutation rate and are transmitted by mosquito bites (phlebotomy genus), insects found mainly in the warmer, drier areas of the Iberian Peninsula. These viruses are common in most of the Mediterranean countries of Western Europe, as well as in Cyprus and Turkey. As there is no actual vaccine against infection, epidemiological surveillance, control and prevention measures to avoid phlebotomine sandfly bites are crucial to avoid viral infections.
“Both TOSV and SFSV have been detected in a variety of domestic animals (dogs, cats, goats, horses, pigs, cows), but they can also infect humans and cause disease,” says the researcher, who works in the UB Department of Evolutionary Biology, Ecology and environmental sciences.
In humans, feblovirus infections are usually asymptomatic and often result in a three-day fever — pappatasis feve — that closely resembles the flu. “SFSV can cause a period of brief high fever accompanied by headache, rash, photophobia, eye pain, myalgia and general weakness. TOSV can cause the same manifestations as SFSV, but it can also be responsible for various central or peripheral neurological signs such as meningitis and encephalitis. In fact, some summer encephalitis is caused by TOSV,” notes Serra-Cobo.
Viruses in migratory birds
The results of the new study suggest that birds could be the reservoir or amplification of these viruses. From infected birds, mosquitoes can be infected and then bite animals or humans. In particular, the study highlights the important role played by quail (coturnix coturnix) in the infection dynamics of phleboviruses.
“Migratory birds play an important role in disease transmission due to their high mobility from one area to another, making them potential vectors of diseases that can affect domestic animals and human health,” Serra-Cobo points out.
“The quail is a migratory species as well as a hunter, which increases the potential transmission of disease through direct contact through the food chain. In this context, the regular detection of pathogens is of great importance to predict future disease risks for wildlife and humans,” concludes the researcher.