Malaria, Malaria, A Re-emerging Health A Re-emerging Health Threat to the Republic Threat to the Republic
of Koreaof KoreaCOL (Ret) Terry A. Klein, PhD
Regional Emerging Infectious Disease Consultant Force Health Protection, 18th Medical Command
Republic of Korea
12 February 2007
Collaborators
• Dr. Heung-Chul Kim, 5th MED DET
• Dr. Won-Ja Lee, Korea NIH
• Dr. Desmond Foley, WRBU
• LTC William Sames, 18th MEDCOM
• Dr. Leopoldo Rueda, WRBU
• Dr. Richard Wilkerson, WRBU
• Commanders/personnel, MED DETs
History of Malaria in Korea1950-53: vivax malaria presented a health threat to US Forces during the Korean War. 1973: Korea declared itself to be malaria free1993: Plasmodium vivax malaria re-emerged and increased exponentially through 1998. 1998-00: overall, malaria stabilized, increasing slightly.2001-04: malaria rates rapidly decreased annually.2005: malaria rates increased, continue to increase in 2006.Chemoprophylaxis:
1997-98: US Forces, increased reliance (>14,000), then decreased usage to 1,300 personnel in 2000 and <500 from 2001-Present.1998-2005: increased reliance by ROK Military (40,000 to >165,000) Evidence that ROK soldiers placed on chemoprophylaxis have higher rates of delayed malaria.2006: ROK Army increases chemoprophylaxis to 200,000
Vivax Malaria – EpidemiologyHealth
• Vivax malaria is a significant health threat.• Vivax malaria is non-lethal. • High Risk Areas - defined only by troop movement
and clinical reporting, not area of transmission.• Once diagnosed and treatment initiated, soldiers lose
about 72--96 hours of duty time. Total recuperation may extend 1 week+.
• Malaria is a significant threat to the blood supply for Korea.
• No vaccine available.
Increased Pressure to put US and ROK soldiers on chemoprophylaxis. – Departing US personnel presents a significant US public
health threat at their new station in the US.– 2004, at least 6 US Soldiers deployed to Iraq from Korea
developed malaria (attributed to exposure in Korea).– Vivax malaria among retiring ROK soldiers pose a threat to
the spread of malaria throughout Korea.
• Hasty reliance on chemoprophylaxis minimizes the doctrinal importance of PPM, vector surveillance and control.
• Potential resistance of P. vivax to chloroquine and/or primaquine.
Vivax Malaria – Epidemiology Chemoprophylaxis
Vivax Malaria - Epidemiology Transmission
• Vector(s)– Zoophilic (?) – Low-survival rates– Low infection rates/
high vector density– Distributions
unknown– Vector status not
well understood
• Environment– Low/moderate endemicity – Epidemic outbreaks– Climate (cold winters,
typhoons) favorable for short periods
• Host – Delayed or immediate
disease manifestation.– Low immunity
Annual Trend of Malaria Cases Diagnosed in the Republic of Korea
YEAR
Chemoprophylaxis initiated
(16,000)
(37,000)
(60,000)
(90,000)
(120,000)
(145,000)
(165,000) (200,000)
As of 31 December 06
Annual Trend of Malaria Cases Among US Soldiers and Attributed to exposure in the Republic of Korea,
1993 – 2006
YEAR
Chemoprophylaxis Initiated
Chemoprophylaxis stopped, except for JSA and Cp
Greaves
Number of Cases of Plasmodium Spp. In US Servicemen Attributed to Exposure in Korea and
Other Countries
Nu
mb
er M
alar
ia C
ases
Month
Latent, Non-latent, and Unknown Forms of Vivax Malaria Diagnosed in Korea and Outside of Korea
Nu
mb
er M
alar
ia C
ases
Month
Month of Diagnosis for Latent and Non-latent Vivax Malaria Forms
Nu
mb
er M
alar
ia C
ases
Month
Distribution of Malaria, USFK, 2002 - 2006
Adult Mosquito Surveillance
CDC Light TrapNew Jersey Light
Trap
Human-Bait Mosquito Magnet RatioAnopheles sp. 2.22 1.09 2.04Aedes sp. 0.31 1.67 0.19Culex sp. 0.03 0.72 0.04
Mean Number of Mosquitoes Collected and Human Biting Propensity - Sept. 03
Species
Anopheles sinensis 1 189.4 n/d 0.1Culex tritaeniorhynchus 2 0 n/d 0Aedes vexans 481.4 n/d 0.4
SEPTEMBERAnopheles sinensis 59.8 1.5 0Culex tritaeniorhynchus 741.9 1 0.25Aedes vexans 320 2.5 0.125
Mosquito Surveillance Trapping Methods - 2000
JUNE
Mosquito Magnet +
Octenol3
New Jersey Light Trap
CDC Light Trap
1 Anopheles sinensis group includes An. lesteri, An. pullusand two undescribed species.2 Culex tritaeniorhynchus are rarely collected in June nearthe demilitarized zone.3 All traps baited with octenol, an artificial attractant, collected more An. sinensis, Cx. tritaeniorhynchus, and Ae.vexans, but fewer Cx. pipiens.
Taxonomy and Distribution of Malaria Vectors
• 5 members of the An. sinensis GroupAn. sinensisAn. lesteriAn. pullusAn. belenraeAn. kleini
• Identify vector species• Identify vector species distributions• Identify vector species habitats
1 Km
Determine Species Distribution
1 Km
KSK-2
An. sinensis s.s. An. kleini
Darker blue indicates areas of greater agreement amongst 10 replicate Ecological Niche models
An. pullus An. belenrae
Geographical Distribution of Four Members of the An. sinensis Group
An. lesteri, 1, 0.8%
An. pullus,
48, 39.3%
An. kleini,
63, 51.6%
An. belenrae 3, 2.5%
An. sinensis , 7, 5.7%
An. sinensis
62, 100.0%
An. sneroides
1, 2.8%
An. belenrae, 1, 2.8% An.
pullus, 3, 8.3%
An. Sinensis, 29, 80.6%
An. kleini, 2, 5.6%
An. sinensis 22, 91.7%
An. belenrae, 2, 8.3% An. pullus,
1, <0.1% An. keini 1, <0.1%
An. belenrae 3, 0.5%
An. sinensis
619, 99.2%
An. sinensis
467, 95.9%
An. belenrae, 1, 0.2%
An. kleini, 15, 3.1% An. pullus
4, 0.8%
An. pullus 8, 26.6%
An. kleini 3, 10.0%
An. belenrae 1, 3.3%
An. sineroides
2, 6.7%
An. sinensis 16, 53.3%
An. sinensis 24, 24.5%
An. belenrae8, 8.2%
An. kleini 50, 51.0%
An. pullus 16, 16.3%
Cp Bonifas
Number/Proportion of Species from of Adult AnophelesMosquitoes Collected by NJ Light Trap, ROK, Jun-Oct 2005
Warrior Base
An. lesteri, 1, 1.4%
An. pullus 2, 2.9%
An. kleini 22, 31.9%
An. belenrae 6, 8.7%
An. sineroides
1, 1.4%
An. Sinensis37, 53.6%
Rodriguez Range
Cp Humphreys
Gunsan AB
Gwangju AB
Cp Long
Cp Eagle
Cp Carroll
An. belenrae8. 0.7% An. kleini
439. 40.0%
An. Pullus33. 3.0%
An. sinensis
617. 56.2%
An. Sineroide1. 0.1%
TongilchonN=1098
Proportion of Anopheles spp. Larvae, Republic of Korea, Mar-Oct 2005
Gimcheon N=45
An. sinensis
730. 62.8% An. Pullus178. 15.3%
An. kleini 212. 18.2%
An. belenrae38. 3.3%
An.lesteri5, 0.4%
Majeong-ri,N=1163
An. belenrae1. 0.5% An. kleini
26. 14.1%
An. Pullus5, 2.7%
An. sinensis
139. 75.1%
An. Lesteri12, 6.5
GimpoN=183
An. belenrae7. 4.5%
An. kleini 4, 2.5%
An. Pullus31, 19.7%An. sinensis
111. 70.7%
An. Lesteri4, 2.5%
IlsanN=157
An. koreicus5. 2.0% An. kleini
23. 9.4%
An. sineroides10. 4.1%An. sinensis
205. 84.0%
An.lesteri1, 0.4%8.2%
CheongpyeongN=244
An. sinensis
28. 100.0%
TaebaekN=28
An. somerpode
s7. 8.1%
An. kleini 2. 2.3%
An. Pullus1, 1.2%An.
sinensis76. 88.4%
JaecheonN=86
An. sinensis
251. 100.0%
Anmyeon-doN=251
Gimcheon N=45
An. kleini 1. 0.9%
An. sinensis107. 99.1%
An. sinensis69. 97.2%
An. kleini 1. 1.4%
An. sineroides1. 1.4%
JeonjuN=108
GwangjuN=99
BoseungN=71
An. kleini 1. 1.0%
An. sinensis98. 99.0%
An. kleini 1. 1.3%
An. sinensis75. 98.7%
Cheongsong N=76
An. sinensis144. 94.7%
An. kleini 5. 3.3%
An. Sineroides3. 2.0%
Busan N=152
An. sinensis7. 100.0%
Geoje Is N=7
An. sinensis40. 97.6%
An. pullus1. 2.4%
Sacheon N=41
An. sinensis43. 100.0%
Jeju Is N=43
Proportion of Anopheles spp. Larvae, Republic of Korea, Mar-Oct 2005
RISK REDUCTION
• Develop and implement efficient and effective vector and disease reduction strategies.– Larval control
• Eliminate water source.• Drain rice paddies
periodically.• Pesticides.
– Adult control• Pesticides.• Repellents.
• Evaluate vector and disease control strategies.
Pre-ULV fogging
Post-ULV fogging
Warrior Base
• Develop, evaluate, and implement efficient and effective vector and disease reduction strategies
Malaria Control
EDUCATION
• Public awareness.– Television– Newspaper– Health related pamphlets– Inform the public of their
responsibilities
• Human surveillance.– Reporting requires a
standardized program
PERSONAL PROTECTIVE MEASURES
PPM is safe and it works!
Personal Protection
1One patient reported DEET use, but didn't know if formulation was civilian or military.2One patient reported using bed nets only when in tents; otherwise they were not used when sleeping on the ground.3Not all respondents answered all questions.4Policy changed to sleeves rolled up while in installations, but down when in the field.
Year 2001 2002 2003 2004 2005 2006
Countermeasure3
Yes (%) Yes (%) Yes (%) Yes (%) Yes (%) Yes (%)
(n=12) (n=19) (n=17) (n=16) (n=9) (n=5)
Permethrin-BDU 2 (17) 3 (16) 8 (47) 3 (20) 1 (11) 0 (0)
Uniform Discipline 9 (75) 8 (42) 144 (100) 12 (80) 9 (100) 5 (100)
DEET 71 (58) 10 (53) 5 (31) 7 (47) 4 (44) 0 (0)
Bed Net 12 (8) 4(21) 1 (6) 2 (13) 1 (11) 0 (0)
QUESTIONS