Akashi H; Kaku Y; Kong XG; Pang H.
Sequence determination and phylogenetic analysis of the Akabane bunyavirus
S RNA genome segment.
Journal of General Virology, 1997 Nov, 78 ( Pt 11):2847-51.
Abstract: The nucleotide sequence of
the small (S) RNA segment of Akabane (AKA)
bunyavirus was determined. The segment is 858 nucleotides long and contains
two overlapping open reading frames (ORFs), which encode the nucleocapsid
(N) and nonstructural (NSs) proteins, consistent with other bunyaviruses.
Comparisons with the Aino virus S RNA sequence indicated that there is
73.5% identity in nucleotide sequence. However, the sequence identity of
the 5' non-coding region of the genomic RNA between these two viruses is
only 55%. The N ORFs from 20 Japanese and 2 Australian isolates of AKA
virus were sequenced and subjected to phylogenetic analysis. This suggested
that AKA virus has evolved in multiple lineages. Twenty-three isolates were
grouped into three major clusters, and the cluster which includes recent
isolates was subdivided into two branches. Thus, phylogenetic analysis of
the AKA virus N protein gene gives a greater insight into bunyavirus
La Crosse Virus
Huang C; Thompson WH; Karabatsos N;
Grady L; Campbell WP.
Evidence that fatal human infections with La Crosse virus may be
associated with a narrow range of genotypes.
Virus Research, 1997 May, 48(2):143-8.
Abstract: La Crosse (LAC) virus belongs to
the California (CAL) serogroup of
the genus Bunyavirus, family Bunyaviridae. It is considered one of the most
important mosquito-borne pathogens in North America, especially in the
upper Mid-West, where it is associated with encephalitis during the time of
year when mosquitoes are active. Infections occur most frequently in
children and young adults and, while most cases are resolved after a period
of intense illness, a small fraction (< 1%) are fatal. At present there
have only been three isolates of LAC virus from humans all made from brain
tissue postmortem. The cases yielding viruses are separated chronologically
by 33 years and geographically from Minnesota/Wisconsin (1960, 1978)
to Missouri (1993). The M RNA sequence of the first two isolates was
previously reported. The present study extends the observations to the
isolate from the 1993 case and includes several mosquito isolates as well.
A comparison of the M RNAs of these viruses shows that for the human
isolates both nucleotide sequence and the deduced amino-acid sequence of
the encoded proteins are highly conserved, showing a maximum variation of
only 0.91% and 0.69%, respectively. This high degree of conservation over
time and space leads to the hypothesis that human infections with this
particular genotype of LAC virus are those most likely to have a fatal
outcome. It is also shown that a virus with this genotype could be found
circulating in mosquitoes in an area more or less intermediate between the
locations of the first and second fatal cases.