''Toscana phlebovirus'' (TOSV) is an

arbovirus Arbovirus is an informal name for any virus that is transmitted by arthropod vectors. The term ''arbovirus'' is a portmanteau word (''ar''thropod-''bo''rne ''virus''). ''Tibovirus'' (''ti''ck-''bo''rne ''virus'') is sometimes used to more spe ...

(

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

-borne virus) belonging to ''

Bunyavirales ''Bunyavirales'' is an order of segmented negative-strand RNA viruses with mainly tripartite genomes. Member viruses infect arthropods, plants, protozoans, and vertebrates. It is the only order in the class ''Ellioviricetes''. The name ''Bunyavir ...

'', an order of negative-stranded, enveloped

RNA virus An RNA virus is a virusother than a retrovirusthat has ribonucleic acid (RNA) as its genetic material. The nucleic acid is usually single-stranded RNA ( ssRNA) but it may be double-stranded (dsRNA). Notable human diseases caused by RNA viruses ...

es. The virus can be transmitted to humans by the bite of an infected

sandfly Sandfly (or sand fly) is a colloquial name for any species or genus of flying, biting, blood-sucking dipteran (fly) encountered in sandy areas. In the United States, ''sandfly'' may refer to certain horse flies that are also known as "greenhea ...

of the genus ''

Phlebotomus ''Phlebotomus'' is a genus of " sand flies" in the Diptera family Psychodidae. In the past, they have sometimes been considered to belong in a separate family, Phlebotomidae, but this alternative classification has not gained wide acceptance. E ...

''. Toscana is not normally associated with disease, as indicated by high seroprevalence rates (up to 25%) in endemic areas, but in common with other sandfly transmitted viruses such as '' Naples virus'' and '' Sicilian virus'', infection may result in

Pappataci fever Pappataci fever (also known as Phlebotomus fever and, somewhat confusingly, sandfly fever and three-day fever) is a vector-borne febrile arboviral infection caused by three serotypes of Phlebovirus. It occurs in subtropical regions of the Eastern ...

, an illness with mild fever,

headache Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches. Headaches can occur as a result ...

and

myalgia Myalgia (also called muscle pain and muscle ache in layman's terms) is the medical term for muscle pain. Myalgia is a symptom of many diseases. The most common cause of acute myalgia is the overuse of a muscle or group of muscles; another likel ...

. In serious cases that go undiagnosed, acute

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion or ...

meningoencephalitis Meningoencephalitis (; from ; ; and the medical suffix ''-itis'', "inflammation"), also known as herpes meningoencephalitis, is a medical condition that simultaneously resembles both meningitis, which is an infection or inflammation of the menin ...

and

encephalitis Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, ...

may occur. There is no specific treatment for infection, so treatment is supportive, reducing the severity of symptoms until the immune system has cleared the infection. The virus is found in most countries that border the Mediterranean Sea, with the highest incidence in Italy. Infection rates peak during the summer time as sandfly populations grow more abundant.

Virology

Structure and genome

TOSV has a spherical, enveloped body with an 80–120 nm diameter. The genome is encased in a nucleocapsid and consists of negative-sense RNA broken into three segments, termed L, M and S. L is about 6,400 nucleotides in length, M about 4,200 nucleotides in length, and S about 1,900 nucleotides in length. L encodes for the viral polymerase, M encodes for structural glycoproteins and S encodes for nucleic proteins.

Diagnosis

Laboratory diagnosis of TOSV infection can be performed through the use of

ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presence ...

immunofluorescence Immunofluorescence is a technique used for light microscopy with a fluorescence microscope and is used primarily on microbiological samples. This technique uses the specificity of antibodies to their antigen to target fluorescent dyes to specif ...

and/or neutralization tests, but reverse transcription,

real-time polymerase chain reaction A real-time polymerase chain reaction (real-time PCR, or qPCR) is a laboratory technique of molecular biology based on the polymerase chain reaction (PCR). It monitors the amplification of a targeted DNA molecule during the PCR (i.e., in real ...

assays are preferred because they are less time-consuming and reduce the risk of contamination.

Epidemiology

This virus is a leading cause of acute meningitis between May and October in Central Italy and in other northern Mediterranean countries (

Croatia , image_flag = Flag of Croatia.svg , image_coat = Coat of arms of Croatia.svg , anthem = "Lijepa naša domovino"("Our Beautiful Homeland") , image_map = , map_caption = , capit ...

, France, Greece, Portugal and Spain) as well as several of the eastern Mediterranean countries (Cyprus and Turkey). It is among the 3 most prevalent viruses associated with meningitis during the warm seasons: the other two are

enterovirus ''Enterovirus'' is a genus of positive-sense single-stranded RNA virus An RNA virus is a virusother than a retrovirusthat has ribonucleic acid (RNA) as its genetic material. The nucleic acid is usually single-stranded RNA ( ssRNA) but it ma ...

es and

herpesvirus ''Herpesviridae'' is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word ''ἕρπειν ...

es.

History

Toscana virus (TOSV) was first isolated in 1971 from ''

Phlebotomus perniciosus ''Phlebotomus'' is a genus of "sand fly, sand flies" in the fly, Diptera family Psychodidae. In the past, they have sometimes been considered to belong in a separate family, Phlebotomidae, but this alternative classification has not gained wide ...

'' and ''

Phlebotomus perfiliewi ''Phlebotomus'' is a genus of " sand flies" in the Diptera family Psychodidae. In the past, they have sometimes been considered to belong in a separate family, Phlebotomidae, but this alternative classification has not gained wide acceptance. ...

'' in

Monte Argentario Monte Argentario is a ''comune'' (municipality) and a peninsula belonging to the Province of Grosseto in the Italian region Tuscany, located about south of Florence and about south of Grosseto. The peninsula is connected with the mainland by thre ...

(

Grosseto Grosseto () is a city and ''comune'' in the central Italian region of Tuscany, the capital of the Province of Grosseto. The city lies from the Tyrrhenian Sea, in the Maremma, at the centre of an alluvial plain on the Ombrone river. It is the m ...

Tuscany Tuscany ( ; it, Toscana ) is a Regions of Italy, region in central Italy with an area of about and a population of about 3.8 million inhabitants. The regional capital is Florence (''Firenze''). Tuscany is known for its landscapes, history, art ...

References

{{DEFAULTSORT:Toscana Virus Phleboviruses