Ein Team von Wissenschaftlern unter Federführung des Robert Koch-Instituts
hat die Wildtier-Quelle des Ebolafieber-Ausbruchs in Westafrika
eingegrenzt und bisherige Vermutungen zum Reservoir des Virus in
Wildtieren bestätigt.
Die Arbeiten sind in der Fachzeitschrift EMBO Molecular Medicine erschienen, in der Januarausgabe 2015, die am 30.12.2014 veröffentlicht wurde.
Beteiligt an dem internationalen interdisziplinären Team waren das Max-Planck-Institut für Evolutionäre Anthropologie in Leipzig, die Wild Chimpanzee Foundation in Guinea, die Phillips Universität Marburg, das Institut für Tropenmedizin und internationale Gesundheit an der Charité Universitätsmedizin Berlin und die McGill University, Montreal, Canada (“Investigating the zoonotic
origin of the West African Ebola epidemic”, EMBO Molecular Medicine Januar
2015).
Das Team war im April 2014 in Guinea, um zu untersuchen, ob im Rahmen des
aktuellen Ausbruchgeschehens auch Wildtiere von Ebola betroffen sind.
Frühere Krankheitsausbrüche bei Menschen waren mit erheblichen Todesfällen
unter Wildtieren assoziiert, vor allem Menschenaffen und kleine, im Wald
lebende Antilopen (Ducker); bei der Verarbeitung des Fleischs tot
aufgefundener Tiere kann das Virus auf den Menschen überspringen. In
Guinea fanden die Forscher keine Hinweise auf eine erhöhte Sterblichkeit
unter Wildtieren, die Populationen scheinen sich nicht verändert zu haben.
Das Team untersuchte auch die Umgebung des Indexpatienten, mit dem der
Ausbruch begonnen hat, ein zweijähriger Junge in der Ortschaft Meliandou
in Guinea. Die Umgebung dieser Ortschaft ist stark durch den Menschen
geprägt, es gibt dort keinen tropischen Urwald wie bei den Orten in
Zentralafrika, wo frühere Ebolafieberausbrüche begonnen hatten. Bisher ist
das Reservoir des Ebolavirus nicht eindeutig geklärt. Flughunde (die
wahrscheinlich selbst nicht an Ebolafieber erkranken) werden seit einiger
Zeit als Tier-Reservoir angesehen. Die Wissenschaftler fanden fünfzig
Meter vom Wohnort des Jungen entfernt einen einzelnen hohlen Baum, in dem
die Kinder vor Ort oft gespielt haben. Obwohl der Baum kurz vor dem
Eintreffen der Wissenschafter gebrannt hatte, konnte das Team die
Erbsubstanz der Flughunde-Art nachweisen, die vor dem Brand auf dem Baum
gelebt hatte. Gefunden wurde die Erbsubstanz in Boden und Ascheproben. Es
handelte sich um Mops condylurus, eine Art (Spezies), die schon bei
früheren Ebolaausbrüchen als mögliches Reservoir diskutiert worden ist und
von der bekannt ist, dass sie Ebolavirus-Infektionen überlebt und in der
Antikörper gegen Ebolaviren gefunden worden waren. Die EMBO-Arbeit ist
vermutlich der bestmögliche Einblick, der in die Ursprünge des aktuellen
Ausbruchs zu gewinnen ist.
Nachfolgend eine ausführliche Darstellung der Studienergebnisse in
englischer Sprache. Die Veröffentlichung in der Fachzeitschrift EMBO
Molecular Medicine kann auf Anfrage mit Embargo zur Verfügung gestellt
werden.
----------------------------
Wildlife origins of West African Ebola virus disease outbreak narrowed
down
In April 2014, shortly after the World Health Organization announced that
the Zaire Ebolavirus was responsible for a number of deaths in
southeastern Guinea, an international team began the search for the animal
origins of the current Ebola virus disease epidemic. The team wanted to
know whether there was a larger Ebola virus outbreak happening in wildlife
in the region and how the index case, a two-year-old boy in Meliandou,
Guinea, might have gotten infected and sparked the epidemic that has since
spread into other areas of Guinea and then Sierra Leone, Liberia, Nigeria,
Senegal, USA, Spain and Mali, representing the largest ever recorded
outbreak.
To address these questions, Fabian Leendertz, head of the group
“Epidemiology of Highly Pathogenic Microorganisms” at the Robert Koch
Institute, Berlin, assembled a large international interdisciplinary team
consisting of virologists, veterinarians, ecologists, epidemiologists and
an anthropologist stemming from various institutions; the Robert Koch-
Institute, Berlin, Germany, the Max-Planck-Institute for Evolutionary
Anthropology, Leipzig, Germany, the Wild Chimpanzee Foundation, Guinea,
the Phillips University of Marburg, Germany, the Institute of Tropical
Medicine and International Health, Charité, Berlin, Germany, and the
McGill University, Montreal, Canada. The manuscript reporting their
findings is published Dec 30th 2014 in EMBO Molecular Medicine (Issue
January 2015).
The team first investigated whether there were signs of a recent decline
in wildlife populations in the two largest protected areas in southeastern
Guinea. During past Ebola virus disease outbreaks, particularly in Central
Africa, the virus has caused major die offs in wildlife, particularly in
great apes and duikers, where up to 90% population declines have been
reported and this sometimes led to hunters contracting the virus by
handling and consuming carcasses found in the forest. The monitoring team
did not encounter any wildlife carcasses in their surveys, nor did they
document a recent decline in wildlife densities in the region. This
suggests that there was likely not an “amplifying epidemic” in wildlife in
the region, which could have enabled the virus to jump into the human
population.
While the team was monitoring wildlife densities, it was announced by
local health authorities that the first human case was a two-year-old boy
from the small village of Meliandou. The landscape in that region is
heavily human-modified, with Meliandou surrounded by plantations and
bushland rather than tropical rainforests, as was the case for index
villages in many previous Zaire Ebolavirus outbreaks. The team then set
about to investigate how that two-year-old boy might have come into
contact with the virus.
People, including children, were questioned about their hunting practices
and contact to bushmeat. As in many other parts of Africa, both adults and
children in the region hunt bats rather opportunistically. Children
however tend to focus on small insectivorous bats, which they hunt under
the roofs of houses or in other hides around the village. Once caught and
killed, the bats are put on a stick and roasted over a fire. Even though
this hunting practice is common throughout the region, special features in
Meliandou might have been involved in enabling the transmission of the
Ebola virus to a two-year-old boy. The team discovered a large burnt tree
about 50 meters from the home of the index case, near a path used by women
to reach their washing place at a small river. Children reported that they
used to play regularly in and around this hollow tree, but that it had
burned accidentally on March 24th, shortly before the research team
arrived. Luckily the team was able to identify the species of bats that
had inhabited this tree by identifying its DNA in soil and ash samples and
deep-sequencing them. The bat species was identified as Mops condylurus, a
species that has been discussed as a possible reservoir in early Ebola
virus disease outbreaks in central Africa, it has then been shown to
survive experimental infections and has been found with antibodies against
Ebola viruses in the wild. Since the tree was burned, this species of bat
was not found any more in Meliandou, but other fruit- and insect-eating
bats were caught and subsequently analyzed for Ebola virus infection. As
in many outbreaks before, no virus could be found.
The work presented by Leendertz and colleagues likely provides the best
insight we will get into the origins of the current epidemic, but further
in-depth ecological and experimental studies are urgently needed to
understand the role of these and other bat species in Ebola viruses
transmission and the circulation of these viruses in nature, to ultimately
allow us to prevent future outbreaks.
In line with the “One Health” concept, (a worldwide strategy for expanding
interdisciplinary collaborations and communications in all aspects of
health care for humans, animals and the environment) the researchers
emphasize that culling or eviction attempts targeting bat colonies aimed
at mitigating human-wildlife conflicts or reducing disease transmission
risk are frequently unsuccessful; in some cases even producing effects
opposite to those desired by the initiative. Health education initiatives
should inform the public about potential disease risks posed by bats,
recommend minimizing contact with bats, and advice against the consumption
of bats. Education programs should further teach about the crucial roles
bats play in the ecosystem, including pollination, seed dispersal and
insect reduction. These ecosystem services provide invaluable benefits to
people directly and indirectly, thereby supporting local livelihoods and
healthy ecosystems. Similarly, while the village of Meliandou had the
misfortune to be where this epidemic began, care needs to be taken to
avoid retribution attacks and stigmatization of the region.
Further information
• EMBO Molecular Medicine January 2015
http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291757-4684
• Ebola, RKI activities and recommendations: www.rki.de/ebola-en
Medizin am Abend DirektKontakt
Robert Koch-Institut
Nordufer 20
D-13353 Berlin
www.rki.de
Das Robert Koch-Institut ist ein Bundesinstitut im Geschäftsbereich des
Bundesministeriums für Gesundheit
Susanne Glasmacher
Tel.: 030-18754-2239, -2562 und -2286
Fax: 030-18754 2265
Twitter: @rki_de
hat die Wildtier-Quelle des Ebolafieber-Ausbruchs in Westafrika
eingegrenzt und bisherige Vermutungen zum Reservoir des Virus in
Wildtieren bestätigt.
Die Arbeiten sind in der Fachzeitschrift EMBO Molecular Medicine erschienen, in der Januarausgabe 2015, die am 30.12.2014 veröffentlicht wurde.
Beteiligt an dem internationalen interdisziplinären Team waren das Max-Planck-Institut für Evolutionäre Anthropologie in Leipzig, die Wild Chimpanzee Foundation in Guinea, die Phillips Universität Marburg, das Institut für Tropenmedizin und internationale Gesundheit an der Charité Universitätsmedizin Berlin und die McGill University, Montreal, Canada (“Investigating the zoonotic
origin of the West African Ebola epidemic”, EMBO Molecular Medicine Januar
2015).
Das Team war im April 2014 in Guinea, um zu untersuchen, ob im Rahmen des
aktuellen Ausbruchgeschehens auch Wildtiere von Ebola betroffen sind.
Frühere Krankheitsausbrüche bei Menschen waren mit erheblichen Todesfällen
unter Wildtieren assoziiert, vor allem Menschenaffen und kleine, im Wald
lebende Antilopen (Ducker); bei der Verarbeitung des Fleischs tot
aufgefundener Tiere kann das Virus auf den Menschen überspringen. In
Guinea fanden die Forscher keine Hinweise auf eine erhöhte Sterblichkeit
unter Wildtieren, die Populationen scheinen sich nicht verändert zu haben.
Das Team untersuchte auch die Umgebung des Indexpatienten, mit dem der
Ausbruch begonnen hat, ein zweijähriger Junge in der Ortschaft Meliandou
in Guinea. Die Umgebung dieser Ortschaft ist stark durch den Menschen
geprägt, es gibt dort keinen tropischen Urwald wie bei den Orten in
Zentralafrika, wo frühere Ebolafieberausbrüche begonnen hatten. Bisher ist
das Reservoir des Ebolavirus nicht eindeutig geklärt. Flughunde (die
wahrscheinlich selbst nicht an Ebolafieber erkranken) werden seit einiger
Zeit als Tier-Reservoir angesehen. Die Wissenschaftler fanden fünfzig
Meter vom Wohnort des Jungen entfernt einen einzelnen hohlen Baum, in dem
die Kinder vor Ort oft gespielt haben. Obwohl der Baum kurz vor dem
Eintreffen der Wissenschafter gebrannt hatte, konnte das Team die
Erbsubstanz der Flughunde-Art nachweisen, die vor dem Brand auf dem Baum
gelebt hatte. Gefunden wurde die Erbsubstanz in Boden und Ascheproben. Es
handelte sich um Mops condylurus, eine Art (Spezies), die schon bei
früheren Ebolaausbrüchen als mögliches Reservoir diskutiert worden ist und
von der bekannt ist, dass sie Ebolavirus-Infektionen überlebt und in der
Antikörper gegen Ebolaviren gefunden worden waren. Die EMBO-Arbeit ist
vermutlich der bestmögliche Einblick, der in die Ursprünge des aktuellen
Ausbruchs zu gewinnen ist.
Nachfolgend eine ausführliche Darstellung der Studienergebnisse in
englischer Sprache. Die Veröffentlichung in der Fachzeitschrift EMBO
Molecular Medicine kann auf Anfrage mit Embargo zur Verfügung gestellt
werden.
----------------------------
Wildlife origins of West African Ebola virus disease outbreak narrowed
down
In April 2014, shortly after the World Health Organization announced that
the Zaire Ebolavirus was responsible for a number of deaths in
southeastern Guinea, an international team began the search for the animal
origins of the current Ebola virus disease epidemic. The team wanted to
know whether there was a larger Ebola virus outbreak happening in wildlife
in the region and how the index case, a two-year-old boy in Meliandou,
Guinea, might have gotten infected and sparked the epidemic that has since
spread into other areas of Guinea and then Sierra Leone, Liberia, Nigeria,
Senegal, USA, Spain and Mali, representing the largest ever recorded
outbreak.
To address these questions, Fabian Leendertz, head of the group
“Epidemiology of Highly Pathogenic Microorganisms” at the Robert Koch
Institute, Berlin, assembled a large international interdisciplinary team
consisting of virologists, veterinarians, ecologists, epidemiologists and
an anthropologist stemming from various institutions; the Robert Koch-
Institute, Berlin, Germany, the Max-Planck-Institute for Evolutionary
Anthropology, Leipzig, Germany, the Wild Chimpanzee Foundation, Guinea,
the Phillips University of Marburg, Germany, the Institute of Tropical
Medicine and International Health, Charité, Berlin, Germany, and the
McGill University, Montreal, Canada. The manuscript reporting their
findings is published Dec 30th 2014 in EMBO Molecular Medicine (Issue
January 2015).
The team first investigated whether there were signs of a recent decline
in wildlife populations in the two largest protected areas in southeastern
Guinea. During past Ebola virus disease outbreaks, particularly in Central
Africa, the virus has caused major die offs in wildlife, particularly in
great apes and duikers, where up to 90% population declines have been
reported and this sometimes led to hunters contracting the virus by
handling and consuming carcasses found in the forest. The monitoring team
did not encounter any wildlife carcasses in their surveys, nor did they
document a recent decline in wildlife densities in the region. This
suggests that there was likely not an “amplifying epidemic” in wildlife in
the region, which could have enabled the virus to jump into the human
population.
While the team was monitoring wildlife densities, it was announced by
local health authorities that the first human case was a two-year-old boy
from the small village of Meliandou. The landscape in that region is
heavily human-modified, with Meliandou surrounded by plantations and
bushland rather than tropical rainforests, as was the case for index
villages in many previous Zaire Ebolavirus outbreaks. The team then set
about to investigate how that two-year-old boy might have come into
contact with the virus.
People, including children, were questioned about their hunting practices
and contact to bushmeat. As in many other parts of Africa, both adults and
children in the region hunt bats rather opportunistically. Children
however tend to focus on small insectivorous bats, which they hunt under
the roofs of houses or in other hides around the village. Once caught and
killed, the bats are put on a stick and roasted over a fire. Even though
this hunting practice is common throughout the region, special features in
Meliandou might have been involved in enabling the transmission of the
Ebola virus to a two-year-old boy. The team discovered a large burnt tree
about 50 meters from the home of the index case, near a path used by women
to reach their washing place at a small river. Children reported that they
used to play regularly in and around this hollow tree, but that it had
burned accidentally on March 24th, shortly before the research team
arrived. Luckily the team was able to identify the species of bats that
had inhabited this tree by identifying its DNA in soil and ash samples and
deep-sequencing them. The bat species was identified as Mops condylurus, a
species that has been discussed as a possible reservoir in early Ebola
virus disease outbreaks in central Africa, it has then been shown to
survive experimental infections and has been found with antibodies against
Ebola viruses in the wild. Since the tree was burned, this species of bat
was not found any more in Meliandou, but other fruit- and insect-eating
bats were caught and subsequently analyzed for Ebola virus infection. As
in many outbreaks before, no virus could be found.
The work presented by Leendertz and colleagues likely provides the best
insight we will get into the origins of the current epidemic, but further
in-depth ecological and experimental studies are urgently needed to
understand the role of these and other bat species in Ebola viruses
transmission and the circulation of these viruses in nature, to ultimately
allow us to prevent future outbreaks.
In line with the “One Health” concept, (a worldwide strategy for expanding
interdisciplinary collaborations and communications in all aspects of
health care for humans, animals and the environment) the researchers
emphasize that culling or eviction attempts targeting bat colonies aimed
at mitigating human-wildlife conflicts or reducing disease transmission
risk are frequently unsuccessful; in some cases even producing effects
opposite to those desired by the initiative. Health education initiatives
should inform the public about potential disease risks posed by bats,
recommend minimizing contact with bats, and advice against the consumption
of bats. Education programs should further teach about the crucial roles
bats play in the ecosystem, including pollination, seed dispersal and
insect reduction. These ecosystem services provide invaluable benefits to
people directly and indirectly, thereby supporting local livelihoods and
healthy ecosystems. Similarly, while the village of Meliandou had the
misfortune to be where this epidemic began, care needs to be taken to
avoid retribution attacks and stigmatization of the region.
Further information
• EMBO Molecular Medicine January 2015
http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291757-4684
• Ebola, RKI activities and recommendations: www.rki.de/ebola-en
Medizin am Abend DirektKontakt
Robert Koch-Institut
Nordufer 20
D-13353 Berlin
www.rki.de
Das Robert Koch-Institut ist ein Bundesinstitut im Geschäftsbereich des
Bundesministeriums für Gesundheit
Susanne Glasmacher
Tel.: 030-18754-2239, -2562 und -2286
Fax: 030-18754 2265
Twitter: @rki_de
Keine Kommentare :
Kommentar veröffentlichen