Malaria, A Re-emerging Health Threat to the Republic of Korea COL (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, 5 th MED DET Dr. Won-Ja Lee, Korea NIH Dr. Desmond Foley, WRBU LTC William Sames, 18 th MEDCOM Dr. Leopoldo Rueda, WRBU Dr. Richard Wilkerson, WRBU Commanders/personnel, MED DETs

History of Malaria in Korea : vivax malaria presented a health threat to US Forces during the Korean War. 1973: Korea declared itself to be malaria free 1993: Plasmodium vivax malaria re-emerged and increased exponentially through : overall, malaria stabilized, increasing slightly : malaria rates rapidly decreased annually. 2005: malaria rates increased, continue to increase in Chemoprophylaxis: : US Forces, increased reliance (>14,000), then decreased usage to  1,300 personnel in 2000 and <500 from 2001-Present : 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 – Epidemiology Health 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 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 Number Malaria Cases Month

Latent, Non-latent, and Unknown Forms of Vivax Malaria Diagnosed in Korea and Outside of Korea Number Malaria Cases Month

Month of Diagnosis for Latent and Non-latent Vivax Malaria Forms Number Malaria Cases Month

Distribution of Malaria, USFK,

Adult Mosquito Surveillance CDC Light Trap New Jersey Light Trap 1 Anopheles sinensis group includes An. lesteri, An. pullus and two undescribed species. 2 Culex tritaeniorhynchus are rarely collected in June near the 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 Group An. sinensis An. lesteri An. pullus An. belenrae An. 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. pullusAn. belenrae Geographical Distribution of Four Members of the An. sinensis Group

Cp Bonifas Number/Proportion of Species from of Adult Anopheles Mosquitoes Collected by NJ Light Trap, ROK, Jun-Oct 2005 Warrior Base Rodriguez Range Cp Humphreys Gunsan AB Gwangju AB Cp Long Cp Eagle Cp Carroll

Tongilchon N=1098 Proportion of Anopheles spp. Larvae, Republic of Korea, Mar-Oct 2005 Gimcheon N=45 Majeong-ri, N=1163 Gimpo N=183 Ilsan N=157 Cheongpyeong N=244 Taebaek N=28 Jaecheon N=86

Anmyeon-do N=251 Gimcheon N=45 Jeonju N=108 Gwangju N=99 Boseung N=71 Cheongsong N=76 Busan N=152 Geoje Is N=7 Sacheon N=41 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 1 One patient reported DEET use, but didn't know if formulation was civilian or military. 2 One patient reported using bed nets only when in tents; otherwise they were not used when sleeping on the ground. 3 Not all respondents answered all questions. 4 Policy changed to sleeves rolled up while in installations, but down when in the field. Year Countermeasure 3 Yes (%) (n=12)(n=19)(n=17)(n=16)(n=9)(n=5) Permethrin-BDU2 (17)3 (16)8 (47)3 (20)1 (11)0 (0) Uniform Discipline9 (75)8 (42)14 4 (100)12 (80)9 (100)5 (100) DEET7 1 (58)10 (53)5 (31)7 (47)4 (44)0 (0) Bed Net1 2 (8)4(21)1 (6)2 (13)1 (11)0 (0)

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