Is climate change needed to vector-borne infectious ... · result of malaria eradication campaigns and dengue transmission ... Rhabdovirus Mossuril Kamese Unknown ... Viruses are

Is climate change needed to vector-borneinfectious diseases re-emergence?infectious diseases re emergence?

Impacts of Climate Change on Infectious diseases Annecy, Les Pensières November 24-26, 2008

JeanJean--Francois SALUZZOFrancois SALUZZO

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Virus transmission to human

Zoonotic disease

Animal Animal

Animal Animal

Vector Vector

Animal Animal

Human Human

ArbovirusesArboviruses

212.07.2010 2

Yellow fever in 1827Yellow fever in 1827

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Yellow fever: the American plagueYellow fever: the American plague

Yellow fever epidemic in the Mississippi Valley in 1878Mississippi Valley in 1878

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Dengue feverDengue fever

Currently dengue fever is the most important vector-borne disease in the world affecting mainly children living in tropical areasareas.

B t i th f th i t th t d lik But in the course of the nineteenth century, dengue like epidemics occurred around the world including various places around the Mediterranean.

The largest dengue outbreak was reported in Greece in 1927 The largest dengue outbreak was reported in Greece in 1927-1928. An estimated 1,000,000 people were infected, and 1000 died of DHF/DSS.

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The fight again YF and dengueThe fight again YF and dengue

In 1900, Walter Reed demonstrated the role

f A d ti YF tof Aedes aegypti as YF vector

Strict mosquito control measures applied first in Cuba and United States was associated with the elimination of the urban disease inStates was associated with the elimination of the urban disease in the Americas.After World War II Ae aegypti disappeared from Europe as aAfter World War II, Ae aegypti disappeared from Europe, as a result of malaria eradication campaigns and dengue transmission was stopped.

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Currently the two major arboviruses, YF and dengue, are located in tropical areas.

World distribution map of Aedes aegypti and dengue in 2005

Ae aegypti

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Ae aegypti + Dengue/DHF

International air traffic International air traffic

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Yellow Fever importation,1979-2002

Year From To

1979 Senegal France1988 W Af i S i1988 W. Africa Spain1996 Brazil USA1996 Brazil Switzerland1999 CIV Germany1999 Venezuela USA2000 Surinam Netherland2001 Gambia Belgium2002 Brazil USA

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Where do new viruses come from?Where do new viruses come from?

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The origin of major emerging viruses associated with The origin of major emerging viruses associated with human disease (1950human disease (1950--2005)2005)

human disease (1950human disease (1950 2005)2005)

America Africa Europe Asia AustraliaAmerica Africa - Europe Asia - AustraliaEnterovirus 71 (USA - 1969) O'nyong-nyong (Ouganda - 1964) DHF (Philippines - 1954) Sin nombre (USA - 1993) Lassa (Nigeria - 1969) Kyasanur forest disease (India - 1956) Junin (1958) Rift Valley fever(Egypt - 1976) Hantaan (Korea - 1975) Machupo (1962) Marburg (Uganda - 1967) Hendra (Australia - 1994) Gunarito (1990) Ebola (Zaïre - 1976) Avian flu (Hong-Kong - 1997)

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Gunarito (1990) Ebola (Zaïre 1976) Avian flu (Hong Kong 1997)Sabia (1993) HIV-1 (Central Africa) Nipah (Malaysia - 1998) HIV-2 (West Africa) SARS (China - 2003) West-Nile (Africa 1999) Metapneumovirus (Holland - 2001)

Chikungunya (Est Africa - 2005)

Predicted emerging disease hotspots due to vectorPredicted emerging disease hotspots due to vector--borne borne pathogenspathogens

(From: K.E. Jones. et al. 2008 Nature: 451: 990-993)

p gp g

(From: K.E. Jones. et al. 2008 Nature: 451: 990 993)

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Epidemiological studies performed at Bangui Pasteur Institute Epidemiological studies performed at Bangui Pasteur Institute (Central African Republic) from 1962(Central African Republic) from 1962--19931993

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Epidemiological studies performed at Bangui Pasteur Epidemiological studies performed at Bangui Pasteur Institute (Central African Republic) from 1962Institute (Central African Republic) from 1962--1993)1993)( p )( p ) ))

The goal of the study was to perform an inventory of viruses circulating in arthropods birds bats and rodentsviruses circulating in arthropods, birds, bats and rodents collected in different areas. The ecology study was associated with extensive surveillance of arbovirusassociated with extensive surveillance of arbovirus disease in man:

A total of 919 viruses was isolated of which 84 different species belonging to 12 genera. Of those, 39 were new viruses.

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Famille Virus

Togaviridae Semliki forestZingilamo*

Virus isolated from

g

Flaviviridae YaoundéWest-Nile

wild bird collected in Central African Republic.

Uganda S

Bunyaviridae IngwavumaBatama*

N t El i

Batama*M'Poko*ArumowotBobaya*

Note: Eleven new viruses were isolated Rhabdoviridae Sandjimba*

Kolongo*NasouleNasouleMossurilGarba*

Ungrouped Ouango*Landjia*Bimbo*B *

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Bangoran*

* New virus

Virus

Arboviruses isolated from Chikungunya

Igbo Orahuman and associated with exanthematic fever

g

Sindbis

BabankiBabanki

Usutu

West-NileWest Nile

Koutango

ZikaZika

Ilesha

BwambaBwamba

Tataguine

Bangui

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Bangui

Zinga

Surveillance of YF and arboviruses associated with anthropophilic Surveillance of YF and arboviruses associated with anthropophilic mosquitoes in Central African Republic (1975mosquitoes in Central African Republic (1975--1985)1985)

Study performed in the field station of BOZO

mosquitoes in Central African Republic (1975mosquitoes in Central African Republic (1975 1985)1985)

Study performed in the field station of BOZO

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Surveillance of YF and arboviruses associated with anthropophilic Surveillance of YF and arboviruses associated with anthropophilic mosquitoes in Central African Republic (mosquitoes in Central African Republic (19751975--19851985))

Undifferentiated savanna of moist type

mosquitoes in Central African Republic (mosquitoes in Central African Republic (19751975 19851985))

yp

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Forest galleries


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Monkey sentinel (YF surveillance)


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Arboviruses isolated from anthropophilic mosquitoes (Aedes*, Anopheles*)

Genus Virus Disease

Alphavirus Chikungunya Middelburg

Fever arthralgia Unknowng

Sindbis Exanthematic fever (EF)

Flavivirus Bagaza Bouboui

Unknown UnknownBouboui

YF West-Nile Wesselsbron

UnknownHemorhagic fever Neurotropic disease Fever

Zika Fever

Bunyavirus Bozo Ilesha

Unknown EF

Bwamba Tataguine M’Poko Pongola

EF EF Unknown Unkno nPongola Unknown

Orbivirus Pata Orungo

Unknown Fever

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Rhabdovirus Mossuril Kamese

Unknown Unknown

* Aedes: Ae opok, Ae africanus ; * Anopheles: An gambiae, An funestus

Bozo virus (ArB7343)

Isolated in the field from mosquito pools:

Aedes opok

Aedes africanus Aedes africanus

Anopheles funestus

C l i Culex pruina

Experimentally transmitted by Ae. Aegypti

Serological survey for Bozo virus in human population in CAR(Sera were tested by PRNT50)

Area Nb sera tested Nb sera positive (%)

Forest 115 22 18%

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Savane 236 26 11%

Sahel 111 2 2%

Epidemiological studies in CAREpidemiological studies in CAR

The experienced gained in CAR revealed:The experienced gained in CAR revealed: A huge diversity of viruses Newly described viruses are very common

(i.e.: one new virus each 100 birds collected) Some viruses are associated with human disease,

but a lot of viruses still orphan Viruses are circulating following an enzootic mode and

regularly transmited to human beingsregularly transmited to human beings And finally, the term “new viruses” is to be replaced by “new described viruses” as these viruses already exist in nature

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described viruses as these viruses already exist in nature.

Dryness as a cause of emerging virusesDryness as a cause of emerging viruses

Movement of people and cattle:Movement of people and cattle:

Y ll fYellow fever

Rift Valley fever

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P l di h h di

The YF outbreak in Burkina faso (1983) Peuls are nomadic shepherding

people. The drougth at the end of 70s bli d th t i t i th tobliged them to migrate in the center

part of Burkina faso and adopt lt ti lif t l i l dialternative lifestyles including

settlement, agriculture.

This nomadic population (30.000 people) was not vaccinated

i t YFagainst YF

50 % of the population was infected by the virus (lethality 4%)

This large outbreak was associated

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with the re-emergence of YF in West Africa

Rift Valley fever in Mauritania in 1987

1986: During the intensive drought at the1986: During the intensive drought at the end of the 70s, nomad shepherds have to move in south Mauritania in an area where an important focus ofan area where an important focus of RVF circulation was identified.

1987 Th i ti t th d f th i1987: The migration at the end of the rainy season from this focus to the North where new dams were constructed was associated with thewas associated with the introduction of RVF virus in this new irrigate area and followed by one the largest RVF outbreak everone the largest RVF outbreak ever reported in West Africa (248 deaths)

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ConclusionConclusion

• Zoonoses from wildlife represent the most significant threat to global health of all emerging infectious disease.global health of all emerging infectious disease.

• Predicted emerging disease hotspots are more concentrated in tropical areas In this zone climate change will have importanttropical areas. In this zone, climate change will have important consequence in the amplification of well established virus like

t b thvector-borne pathogens. • Global effort for emerging infectious disease surveillance need

to be focused on places from where the next important pathogen is likely to emerge. Scientific resource need to be re-allocate in tropical area like Africa, targeting surveillance of at-risk population and climate modification to anticipate potential

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p p p pnew emerging agent.

Is climate change needed to vector-borne infectious ... · result of malaria eradication campaigns and dengue transmission ... Rhabdovirus Mossuril Kamese Unknown ... Viruses are

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