malaria--background occurs in > 90 countries 300-500 million cases a year 2 million deaths a year...
TRANSCRIPT
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
• Hyperendemic• EIRs ~ 200• >90% Falciparum• Acquired
immunity• Multidrug
resistance
• 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, Mefloquine, Halofantrine, Quinine
SP
Mefloquine
SP, Mefloquine
Reports of Chloroquine Resistance in P.vivax
19891990
1995
1995
19911995
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
0
50000
100000
150000
200000
250000
300000
1944 1948 1952 1956 1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000
Year
# C
as
es
INS; PNCMyOEM; DISA Loreto; Proyecto Vigía; NAMRID; CDC
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
Equador
Pacific Ocean
Columbia
Bolivia
Brazil
Loreto
Chile
North Region1999
CQn=27(%)
SPn=32(%)
MQn=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
SPn=26(%)
MQn=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)
Data: INS
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
Reemergenceof malaria
1990 1992 1994 1996 1998 2000
PolicyMeeting
Various non-MOHIn vivo studies
INS/CDC In vivo Studies
Baseline CTStudies
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)
0
20
40
60
80
100
120
1975 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994Year
Cure Rate %
Quinine
Mefloquine
Chloroquine
SP
Data: SMRU
40
60
80
100
1985
- 86
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
Year
Treatment efficacy at Thai-Burmese border
MAS3M15 M25
Cured (%)
Data: SMRU
Combination Therapy
• Will it work for Latin America?– Similar epidemiology– Similar vector activity– Similar species– Similar health infrastructure
• Peru now embarking on changing national policy to CT– Need for evaluation