Transcript Document

Malaria--Background
• Occurs in > 90 countries
• 300-500 million cases a year
• 2 million deaths a year
– >90% deaths in sub-Saharan Africa
– Most deaths in children <5 yrs of age
– Risk factors for death – often delays in
accurate diagnosis and effective
treatment
Malaria-endemic Areas 2000
Africa vs. Americas
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Hyperendemic
EIRs ~ 200
>90% Falciparum
Acquired immunity
Multidrug
resistance
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Hypoendemic
EIRs ~ 0.5
Vivax / Falciparum
No immunity
Multidrug
resistance
Drug Resistance
Resistance to Chloroquine - 1960
Resistance to Chloroquine - 1970
Resistance to Chloroquine - 1980
Resistance to Chloroquine - 2000
Antimalarial Resistence - 1998
(excluding CQ)
SP
SP, Mefloquine
Mefloquine
SP, Mefloquine, Halofantrine,
Quinine
Reports of Chloroquine Resistance
in P.vivax
1995
1995
1995
1991
1990
1989
Surveillance for Drug
Resistance
The Peruvian Experience
History of Malaria in Peru
• Incidence of Malaria
– 1944 - 95,000 cases
– 1965 - 1,500 cases
• Remaining cases confined to
northwestern coastal areas with
occasional reports from border
regions with Ecuador, Colombia, Brazil
Malaria Cases in Peru
1944 - 2000
300000
250000
# Cases
200000
150000
100000
50000
0
1944
1948
1952
1956
1960
1964
1968
1972
Year
INS; PNCMyOEM; DISA Loreto; Proyecto Vigía; NAMRID; CDC
1976
1980
1984
1988
1992
1996
2000
Resistance in Peru?
• Anectodal reports of
– chloroquine (CQ) resistance in the north
– CQ and sulfadoxine/pyrimethamine (SP)
resistance in the Amazon
• Health Center “Cohorts”
• In vivo studies
– various institutions
– various protocols
In Vivo Capacity Building
• Decision to have Instituto Nacional
de Salud (INS) perform In vivo
studies to assess resistance in the
Amazon region
• CDC team trained INS team in the
use of WHO/PAHO In vivo protocol
• Study performed in Iquitos (1998)
– CDC and INS together
In Vivo Sentinel Surveillance
• Inappropriate to continue using
current first line therapies?
• Need for valid data
– “Cohorts” data problematic
– Available in vivo data from differing
protocols
– Policy makers asking for data prior to
implementing changes in first line
therapy
In Vivo Sentinel Surveillance
• 6 sites were chosen
– 3 in northern region
– 3 in Amazon region
• Standardized WHO/PAHO protocol
• Staffing
– Health Center staff
– INS
– CDC
Columbia
Equador
Loreto
Brazil
Pacific Ocean
Bolivia
Chile
North Region
1999
CQ
SP
MQ
n=27(%)
n=32(%)
n=14(%)
RIII
6(22.2)
0(0)
0(0)
RII
13(48.1) 0(0)
0(0)
RI
5(18.5)
0(0)
0(0)
S/RI(T)
3(11.1)
32(100)
14(100)
Total
26(100)
32(100)
14(100)
Data: INS
Amazon Region
Iquitos - 1999
Data: INS
SP
MQ
n=26(%)
n=16(%)
RIII
6(23.1)
0(0.0)
RII
7(26.9)
0(0.0)
RI
5(19.2)
0(0.0)
S/RI(T)
8(30.8)
16(100)
Total
26(100)
41(100)
Research into Policy
• Technical Meeting convened Aug.1999
– Attended by regional health officials and
malaria control officers, MOH officials, INS
scientists, Proyecto Vigia, Instituto de
Medicina Tropical, CDC, NAMRD, PAHO
• Objective: to discuss the regional
antimalarial drug resistance, present study
results, discuss future directions
Research into Policy
• Technical Committee
– endorsed the use of combination therapy (CT)
[SP or mefloquine + artesunate]
– baseline studies to ensure efficacy and safety
prior to widespread implementation
• 2000
– 2 in vivo studies occurring
• 1 in northern region
• 1 in Amazon region
Timeline of Activities
INS/CDC
In vivo Studies
1990
1992
1994
1996
Reemergence
of malaria
1998
2000
Policy
Meeting
Various non-MOH
In vivo studies
Baseline CT
Studies
COMBINATION THERAPY FOR
MALARIA IN PERU
Combination Therapy
• A proposed strategy to delay
antimalarial drug resistance
• Well established modality in TB,
AIDS, Cancer
• Ideal drug is from the Artemisinin
family combined with another (SP,
MQ, AQ)
Combination Therapy
• Data from Thailand suggest that CT
– Halts the progression of resistance
– Decreases the transmission of malaria
– No adverse side effects from
artesunate/artemether
– Safe for use in 2nd/3rd trimesters
Drug resistance in Thailand
(sequential monotherapy)
Cure Rate %
120
Mefloquine
100
Quinine
80
SP
60
40
20
Chloroquine
0
1975
Data: SMRU
1976
1978
1980
1982
1984
Year
1986
1988
1990
1992
1994
Treatment efficacy at Thai-Burmese border
Cured (%)
100
80
60
M15
M25
MAS3
40
Year
Data: SMRU
Combination Therapy
• Will it work for Latin America?
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Similar
Similar
Similar
Similar
epidemiology
vector activity
species
health infrastructure
• Peru now embarking on changing
national policy to CT
– Need for evaluation