Gert van der Hoek
In Memoriam - Editor, Senior Moderator
Archive Number 20070125.0338
Published Date 25-JAN-2007
Subject PRO> Chikungunya, imported, risk of transmission
CHIKUNGUNYA, IMPORTED, RISK OF TRANSMISSION
*****************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>
Date: 25 Jan 2007
From: ProMED-mail<promed@promedmail.org>
With the numerous records of travelers returning home from abroad
infected with chikungunya virus, it is relevant to consider whether
there is any likelihood of the virus being transmitted in areas such
as Europe and other northern countries.
The vectors of chikungunya are mainly African _Aedes_ species
including _Aedes aegypti_ and _Ae. africanus_ none of which occur in
Europe. However, prior to 1945 _Ae. aegypti_ was found occasionally
in several Mediterranean countries, especially at ports. It has since
been eradicated from virtually all of Europe.
But another vector of chikungunya virus appears to be _Ae.
albopictus_, an Asian mosquito that has become notorious after being
introduced into many countries outside Asia, such as the USA,
Israel, Australia, New Zealand as well as several countries in Latin
America and sub-Saharan Africa, and in 14 European countries.
However, _Ae. albopictus_ has not managed to establish itself in
countries with relatively cold weather, such as those in northern
Europe, or where efficient control has rapidly been directed at
invasions. Nevertheless it has managed to survive and spread in some
[warmer] Mediterranean countries, especially in Italy where it has
spread to many regions and provinces.
There are various biological strains of _Ae. albopictus_ and if the
strain is a temperate one then it could survive in other European
counties or areas where the mean summer temperature is at least 20
degrees C, and winter mean temperatures zero degrees C; in these
conditions it would likely survive the cold months in the egg state.
So, there must be the chance that in Europe an infected person
returning from abroad [during the warmer months] could be bitten by
_Ae. albopictus_ which could then bite and infect another person.
As regards North America[/B], _Ae. albopictus_ has been recorded from
at least 28 States, and it is an experimental vector of several
viruses including the equine encephalitis ones, and has been found
naturally infected in the USA with Eastern equine encephalitis.
Both _Aedes aegypti_ and _Ae. albopictus_ occur in Japan, and it is
possible that there could be transmission of chikungunya in the
warmer areas of both Japan and the USA, but I believe there is as
yet no evidence of such transmission.
Useful references are:
1. Gratz, N. G. (2004) Critical review of the vector status of _Aedes
albopictus_. Medical and Veterinary Entomology, 44; 51-75
2. Gratz, N. (2006). Vector- and Rodent-borne Diseases in Europe
and North America. Cambridge University Press, England.
--
Mike Service
ProMED-mail Medical Entomology Moderator
<mservice@liverpool.ac.uk>
http://www.promedmail.org/pls/prome..._BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1000,36071
Published Date 25-JAN-2007
Subject PRO> Chikungunya, imported, risk of transmission
CHIKUNGUNYA, IMPORTED, RISK OF TRANSMISSION
*****************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>
Date: 25 Jan 2007
From: ProMED-mail<promed@promedmail.org>
With the numerous records of travelers returning home from abroad
infected with chikungunya virus, it is relevant to consider whether
there is any likelihood of the virus being transmitted in areas such
as Europe and other northern countries.
The vectors of chikungunya are mainly African _Aedes_ species
including _Aedes aegypti_ and _Ae. africanus_ none of which occur in
Europe. However, prior to 1945 _Ae. aegypti_ was found occasionally
in several Mediterranean countries, especially at ports. It has since
been eradicated from virtually all of Europe.
But another vector of chikungunya virus appears to be _Ae.
albopictus_, an Asian mosquito that has become notorious after being
introduced into many countries outside Asia, such as the USA,
Israel, Australia, New Zealand as well as several countries in Latin
America and sub-Saharan Africa, and in 14 European countries.
However, _Ae. albopictus_ has not managed to establish itself in
countries with relatively cold weather, such as those in northern
Europe, or where efficient control has rapidly been directed at
invasions. Nevertheless it has managed to survive and spread in some
[warmer] Mediterranean countries, especially in Italy where it has
spread to many regions and provinces.
There are various biological strains of _Ae. albopictus_ and if the
strain is a temperate one then it could survive in other European
counties or areas where the mean summer temperature is at least 20
degrees C, and winter mean temperatures zero degrees C; in these
conditions it would likely survive the cold months in the egg state.
So, there must be the chance that in Europe an infected person
returning from abroad [during the warmer months] could be bitten by
_Ae. albopictus_ which could then bite and infect another person.
As regards North America[/B], _Ae. albopictus_ has been recorded from
at least 28 States, and it is an experimental vector of several
viruses including the equine encephalitis ones, and has been found
naturally infected in the USA with Eastern equine encephalitis.
Both _Aedes aegypti_ and _Ae. albopictus_ occur in Japan, and it is
possible that there could be transmission of chikungunya in the
warmer areas of both Japan and the USA, but I believe there is as
yet no evidence of such transmission.
Useful references are:
1. Gratz, N. G. (2004) Critical review of the vector status of _Aedes
albopictus_. Medical and Veterinary Entomology, 44; 51-75
2. Gratz, N. (2006). Vector- and Rodent-borne Diseases in Europe
and North America. Cambridge University Press, England.
--
Mike Service
ProMED-mail Medical Entomology Moderator
<mservice@liverpool.ac.uk>
http://www.promedmail.org/pls/prome..._BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1000,36071