Hemorrhagic fever w/renal synd. - Russia (Bashkortostan) (02)

International Society for Infectious Diseases
<http://www.isid.org>

Source: News agency "Regnum.ru", Tue 12 Sep 2006
[translated from Russian by Correspondent Natalia Pshenichnaya; edited]
<http://www.regnum.ru/news/703218.html>


Since the beginning of the year [2006] 1600 people have fallen ill
with haemorrhagic fever with renal syndrome (HFRS) in the Republic of
Bashkortostan, according to the Territorial Management of
Rospotrebnadzor (The Federal Service for Surveillance of Consumer
Rights and Human Wellfare). At the present time the predicted peak
incidence of HFRS has been reached. Morbidity has increased more than
2-fold in comparison with 2005; 3 HFRS patients have died in hospital.

"Distribution of viral HFRS proceeds cyclically," stated Nasima
Kuchinova, Deputy Head of Territorial Management of Rospotrebnadzor
in Bashkortostan. "Peak incidence [occurs every] 5-6 years. During
the last 3-4 years we have observed low HFRS morbidity in the
Republic, but last year it began to increase rapidly. Now we are on
the verge of [a new peak in virus prevalence]. This has been brought
about by the high density of virus-carrying field mice".

In the opinion of specialists, the dangerous period [in 2006] during
which it is possible to contract HFRS will be extended up to the end
of October. The territory of the Republic of Bashkortostan
(Bashkiria) is one of the largest natural endemic foci of
distribution of HFRS virus in the world. The last peak of morbidity
occurred in 1997 when 9500 people fell ill and there were 34
fatalities

The total area of the Republic of Bashkortostan is 143 000 sq. km
(0.8 percent of the total area of Russia) and its capital is
Ufa. Bashkortostan occupies a large part of the Southern Urals, and
adjoining it are plains. In the north, Bashkortostan borders on the
Perm and Sverdlovsk regions; in the east the Chelyabinsk region; in
the southeast, the south and southwest, the Orenburg region; in the
west the Republic of Tatarstan; and in the northwest, the Udmurt
Republic.

Since June [2006] the number of cases in the Republic appears to
have more than quadrupled, confirming the prediction that 2006 is
likely to be a peak year in the incidence of HFRS. A map and further
information on the Republic of Bashkortostan can be accessed at
<http://map.rin.ru/cgi-bin/main_e.pl?Region=bashkir>.

HFRS is caused caused by a hantavirus. The genus _Hantavirus_ is one
of the 5 genera comprising the family _Bunyaviridae_, a group of
negative-stranded RNA viruses with tripartite genomes. The hosts of
hantaviruses are primarily rodents, and each genetically distinct
hantavirus is usually associated with a single rodent species.
Hantaviruses cause persistent non-pathogenic infections of their
rodent hosts. Human infection is incidental to viral survival and is
almost always a dead end in the infection chain. Unlike viruses of
the other genera of the family _Bunyaviridae_, the hantaviruses are
not transmitted by arthropods. The virus responsible for these
outbreaks of HFRS in the Bashkortostan Republic is likely to belong
to the species Puumala virus, which is a member of the genus _Hantavirus_.

A general description of hantaviruses can be accessed at
<http://www.cdc.gov/ncidod/diseases/hanta/hps/noframes/phys/technicalinfoindex.htm>.


According to Heikki Henttonen of the Vantaa Research Centre,
Finland, in 1997, "Classically, HFRS in Bashkiria has been Puumala
infection (carrier species is the bank vole, _Clethrionomys
glareolus_), and recent personal communication from Bashkiria
suggests the same." -- see ProMED archive 19971029.2206." On a fine
point of mammalogy, voles are not rodents, like rats and mice, but
are insectivores.