Infezioni emergenti: una sfida
continua alla sanità pubblica
Giovanni Rezza
Department of Infectious Diseases
U.S. Surgeon General, 1970
‘It’s time to close the book on
infectious disease… the war against
pestilence has been won’
«Vaccines are victims of their own success»
1979, Smallpox
eradication
Emergent and reemergent infections in the last decades
Sars
Mers_Cov
H7N9
Virus Emergence from
Zoonotic Sources
California, June 1981
HIV
Timing of HIV-1 (M) origin in the
human popolation
Blower SM et al, Science 2000
Genetic relationship between HIV
and primate lentiviruses
Schematic for the emergence of an infectious disease
Introductions from the reservoir are followed by chains of transmission in the human population. Infections
with the introduced strain (open circles) have a basic reproductive number R0<1. Pathogen evolution generates an
evolved strain (filled circles) with R0>1. The infections caused by the evolved strain can go on to cause an
epidemic. Daggers indicate no further transmission
SARS-CORONAVIRUS
Probable cases of severe acute respiratory syndrome, by
reported source of infection*
Singapore, 25 February-30 April, 2003
*Case 1 = 1; Case 2 = 6; Case 3 = 35; Case 4 = 130; and Case 5 = 127. Excludes 28 cases with either no or poorly defined
direct contacts or who were cases translocated to Singapore with no further secondary transmission. MMWR 2003;52:405
SARS-CoV Reservoir?
EBOLA
Ebola epidemics
Main contexts where transmission may occur
Transmission within the family
Contact with dead bodies during burial
ceremonies
Transmission in the hospital setting
Totale dei casi di EVD e decessi
in Guinea, Liberia e Sierra Leone
Paese
Casi
Decessi
Guinea
Liberia
Sierra Leone
3805
10672
13911
2533
4808
3955
Totale
28424
11311
Inoltre sono stati segnalati 20 casi in Nigeria, 8 in Mali,
4 negli USA e 1 in Senegal, Spagna, Italia, e UK.
Number of EVD cases (and non-cases) by
epidemiological week: Monrovia, Liberia
Efficacia degli interventi (isolamento precoce)
il modello UK
Whitty et al. Nature 2014
Globalization and
Climate Change
Chikungunya
Castiglione di Cervia
Castiglione di Ravenna
Epidemic Curve by Presumed Place of Infection
12
11
10
9
Other location
Cervia
Castiglione di Cervia and
Castiglione di Ravenna
8
No. of cases
7
6
5
4
3
2
1
0
23-Jun
30-Jun
7-Jul
14-Jul
21-Jul
28-Jul
4-Aug
11-Aug
18-Aug
25-Aug
1-Sep
8-Sep
15-Sep
West Nile Virus
Giu
Jul
Aug
Sep
Oct
Nov
Giu
Jul
Aug
Sep
Oct
Nov
Giu
Jul
Aug
Sep
Oct
Nov
Giu
Jul
Aug
Sep
Oct
Nov
Giu
Jul
Aug
Sep
Oct
Nov
WNND Confirmed cases, Italy
2008: WNV is back!
20
18
16
14
12
10
8
6
4
2
0
2008
2009
2010
Month of symptoms onset
2011
2012
Men W-135 among refugees and
migrant camp workers
Stefanelli, Adv Microbiol Infect Dis Pub Health 2015
Louse-borne relapsing fever among
refugees from Somalia
Ciervo, Em Infect Dis 2015
Waiting for the ‘pandemic’ virus
An insight on current global threats
Influenza pandemics
switch due to inter-species passage of an avian virus
or rearrangement of avian and human viruses in swine
Influenza
•“Spanish”
Subtype
A/H1N1
•“Asiatic”
A/H2N2
•“Hong Kong” A/H3N2
•“Swine”
A/H1N1
Year
Origin
1917
1957
1968
2009
USA?
Cina
Cina
Mexico
The 2009 Influenza A (H1N1v) ‘mild’ pandemic
H5N1 avian flu:
a pre-pandemic virus?
Family cluster in
North-Sumatra
Influenza virus A/H7N9
Avian flu H7N9 pneumonia
H7N9 human cases in China
MERS-Coronavirus
MERS Coronavirus
Phylogenesis of MERS-Cov
MERS-Cov clusters in Saudi Arabia
Estimated R0 <1
Natural host: bats? Intermediate host: dromedary?
Coming to an airport near you
“The global spread of epidemics”
Science 2014
Complexity in global, network driven contagion phenomena
The global mobility network may explain
effective vs. geographic distance
Contrasting emerging infections
Early detection
•Surveillance systems
•Lab capacity
Rapid response
•Containment measures
•Vaccination
