''Nyavirus'' is a genus of
negative-strand RNA viruses in the family ''
Nyamiviridae
''Nyamiviridae'' is a family of negative-strand RNA viruses in the order ''Mononegavirales''. Ecdysozoa and birds serve as natural hosts. The name is a portmanteau of ''Nya''manini Pan (place of isolation of type species Nyamanini virus in Sou ...
''.
Ticks
Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...
and
birds
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
serve as natural hosts. There are four species in this genus.
History
''Nyamanini nyavirus'' (NYMV) and ''Midway nyavirus (''MDWV) were first isolated in 1957 and 1966 respectively. NYMV has been isolated from cattle egrets (species ''
Bubulcus ibis
The western cattle egret (''Bubulcus ibis'') is a species of heron (family Ardeidae) found in the tropics, subtropics and warm temperate zones. Most taxonomic authorities lump this species and the eastern cattle egret together (called the catt ...
'') and
tick
Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...
s (species ''
Argas walkerae'') in
Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
,
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
,
Nigeria
Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...
,
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...
, and
Thailand
Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...
. MDWV has been isolated from tick of the genus ''
Ornithodoros
''Ornithodoros'' is a genus in the soft-bodied tick family, Argasidae.
Physiology
The opening between the midgut and hindgut has been lost, making the ticks unable to pass digestive waste products out of their bodies.
Taxonomy
The Linnean nam ...
'' collected in
Midway,
Kure
is a port and major shipbuilding city situated on the Seto Inland Sea in Hiroshima Prefecture, Japan. With a strong industrial and naval heritage, Kure hosts the second-oldest naval dockyard in Japan and remains an important base for the Japan M ...
and
Manana islands and northern
Honshu
, historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island separ ...
,
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
.
Antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
to this virus have been found in the black-tailed gulls (species ''
Larus crassirostris'') and black-crowned night herons (species ''
Nycticorax nycticorax
The black-crowned night heron (''Nycticorax nycticorax''), or black-capped night heron, commonly shortened to just night heron in Eurasia, is a medium-sized heron found throughout a large part of the world, including parts of Europe, Asia, and N ...
'').
Structure
Nyaviruses are
enveloped, with spherical geometries. The diameter is around 100 to 130 nm. Genomes are linear, nonsegmented, and around 11.6 kbp in total length. The genome codes for 6 proteins.
[ Their genomes contain six ]open reading frame
In molecular biology, open reading frames (ORFs) are defined as spans of DNA sequence between the start and stop codons. Usually, this is considered within a studied region of a prokaryotic DNA sequence, where only one of the six possible readin ...
s. Of these, only two have been assigned a function: the putative nucleocapsid
A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may ...
protein and RNA-dependent RNA polymerase
RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to t ...
.
Life cycle
Viral replication is nuclear. Entry into the host cell is achieved by attachment of the viral GP glycoproteins to host receptors, which mediates clathrin-mediated endocytosis. Replication follows the negative stranded RNA virus replication model. Negative stranded RNA virus transcription, using polymerase stuttering is the method of transcription. Progeny viruses are released by budding off from the host cell wall. Ticks and birds serve as the natural host.[
]
Taxonomy
The genus has four species:
References
External links
Viralzone: Nyavirus
ICTV
{{Taxonbar, from=Q7070952
Nyamiviridae
Virus genera