Health Effect of Climatic Change: Malaysian Senarios Dr Rozlan Ishak Environmental Health Unit Disease Control Division Ministry of Health Malaysia

Situations 50 years ago Malaria was rampant in Malaysia 460,000 cases a year High mortality and morbidity Every parts of the country were under malaria Even the Island of Penang has malaria Some urban areas were free from malaria

Health problems Water supply was inadequate. Hygiene and sanitation was poor Latrines were lacking in most parts of the country. Bucket latrines was the style of the day. Infectious disease such as cholera, typhoid, dysentery, worms infestation were very common. Dengue is not a problem!

Mosquito borne diseases 50 years later

Malaria

Dengue Fever

Viral Encephalitis

Water Borne Diseases 50 years later

Cholera

Dysentery

Food Poisoning

Typhoid

Hepatitis (all forms)

Climate Change Facts ! Global Warming 2100

Climate Change

Pathways

Climate change and health: pathway from driving forces, through exposures to potential health impact. Source: Climate Change and Human Health – Risks and Reponses. Summary (WHO, 2003)

Biological Factors

Biologic response to changes in climate Global warming and wider fluctuation in weather help to spread diseases Temperatures – affect growth, development and survival of microbes and the vectors Weather affects the timing and intensity of disease outbreaks (McMichael et al, 2003)

Biologic response to changes in climate: Infectious diseases Warmer environment and mosquitoes Boost rate of reproduction Increase the number of blood meal Prolongs their breeding season Shorten the maturation period of microbes they carry

Heavy downpours Drive rodents from burrows: risk of zoonotic diseases Create mosquito breeding sites Faster fungal growth in houses Flush pathogens and chemicals into waterways Milwaukee’s cryptosporidiosis outbreak in 1993 Katrina’s flood 2005: water-borne pathogens and toxins spread. Johor flood 2007 and leptospirosis

Common communicabale diseases sensitive to climate (WHO, 2004) Climate is the primary factor in epidemic Cholera, Malaria Climate plays significant role Meningococcal meningitis, leishmaniasis, dengue, Japanese encephalitis, Rift valley fever, Ross river virus, St. Louis encephalitis, Murray valley fever

Infection & Climate: Potential impact on endemic diseases in Malaysia Trans-mission Evidence for inter-annual variability Climate-epidemic link Strength of climate sensitivity Climate-epidemic relationship quantified Cholera Food & water-borne ***** Increase in sea & air temp. Sanitation √ Malaria Mosquito Temp. & rainfall. Many others Dengue **** Temp., humidity & rainfall ***

Temperature, vectorial capacity of Ann Temperature, vectorial capacity of Ann. maculatus and projected number of malaria cases (Ambu et al. 2003) Temp (oC) Esti. Ma Esti. A Esti. N C 27 20 0.043 10 0.069 28 21 9.9 0.075 29 22 9.8 0.081 30 25 0.050 9.7 0.096 31 9.6 0.12 32 9.5 0.14 33 35 9.4 0.17 34 40 9.3 0.20

Rainfall and dengue outbreak in Malaysia No. days examined for rain Low transmission: no. raining days required for an outbreak High transmission: no. raining days required for an outbreak 30 2.89 0.47 60 4.57 2.15 90 6.25 3.83 120 7.93 5.51 150 9.61 7.19 180 11.29 8.87 210 12.97 10.55 240 14.65 12.33 270 16.33 13.91 300 18.01 15.59 330 19.69 17.27 360 21.37 18.95 Modification of Mogi et al. 1990 model Study the threshold of rainfall actually required to trigger an outbreak Dengue incidence and rainfall data in 1986-1997 Model indicated relatively fewer raining days are required for high transmission Heavy rain flushes off breeding habitats

Potential Health Effects from Global Warming Year 2100

Malaria Year 2100

Dengue Fever Year 2100

Thank you rozlan@dph.gov.my What is our plans? Thank you rozlan@dph.gov.my