Emerging and Re-emerging humans disease Abdul Aziz Djamal

“Emerging and Re-emerging humans disease Abdul Aziz Djamal Dept of Microbiology Andalas University

Emerging Disease Newly identified and previously unknown infectious agent that cause public health problem locally or globally

Re-emerging Infectious Disease Infectious disease that have been known for sometime and had fallen to such a low level and no longer consider as a public health problem and now showing upward trend in prevalence or incidence globally

Examples of Emerging and Re-Emerging Infectious Disease: past 10 years A Fauci, NIAID/NIH, 2005

Major and minor killers: global impact viewed on a ‘Richter’ (logarithmic) scale 7 HIV HBV + HCV Tobacco Infant/child ARI & diarrhoeal dis Malaria Road accidents Non-HIV tuberculosis Measles RSV, Rota virus Influenza Dengue 6 5 Viruses H Papilloma v West Nile virus SARS Ebola Polio Hanta virus Hospital infection Suicide 4 3 2 10, 000 -fold difference in impact 1 Log v. CJD 10 Weiss & Mc. Michael, 2004

Outline of Talk Microbes, infectious diseases: recent trends Infectious diseases as result of major changes in human ecology and environmental – historical transitions; current conditions Examples of infectious disease risks Travel, trade Land use, agriculture Intensive animal husbandry Climate variability, climate change Needed: a more ecological perspective

Receding – then Resurging? 1950 s-60 s: Infectious diseases apparently receding in developed countries Antibiotics and vaccines Pesticides to control mosquitoes Improved surveillance and control measures – internationally coordinated Early 1970 s: Authorities proclaimed end of infectious disease era. Premature! >30 new or newly-discovered human IDs over past 30 yrs We overlooked the ecological/evolutionary dimensions

Avian ’flu, H 5 N 1 Mad Cow Disease (BSE) v. CJD Nipah viral encephalitis, Malaysia (1997 -99) Choi Young-Soo/Associated Press - Yonhap South Korean health workers disinfecting a chicken farm north of Seoul last week. Though 140 million birds have died or been killed as a preventive measure in Asia, the risks of wide human infection are not known. Previous ’flu epidemics (1918 -19, ’ 57, ’ 68) South Korean health workers disinfecting a chicken farm in April, 2005. Though several hundred million birds have died or been killed as a preventive measure in Asia, the human epidemic risk remains unknown.

Human-Microbe Transitions over the Millennia Pre-historic: hunter-gatherers disperse into distant new environments 1. Local agrarianism/herding: 5 -10, 000 yrs ago LE 2. Trans-continental: 1, 000 -3, 000 yrs ago CA 3. Inter-continental: From c. 1500 AD in S es 4. Today, global: Fourth historical transition as e Su es cc cr in ive s

Factors in Emerging/Re-emerging Infectious Diseases • Microbial adaptation and change • Human susceptibility to infection ageing, HIV, IV drugs, transplantation, transfusion • Population growth and density • Urbanization, crowding – social and sexual relations • Globalization of travel and trade • Live animal markets • Intensified livestock production • Misuse of antibiotics (humans & domestic animals) • Changes to ecosystems (deforestation, biodiversity loss) • Global climate change

Zoonotic Sources: Land-use, Livestock, Wild-life Clearing forests for agriculture Viral haemorrhagic fevers in South America: peasant-farmers Guanarito, Sabia, Kunjin, etc. Eating infected animals New variant Creutzfeldt Jacob disease (from BSE) Cultivation of infected animals Nipah viral encephalitis (pig farms in Malaysia) West Nile virus (goose “fois gras” farms in Ramala, Israel) Collection and trade of wild game HIV (bush meat: primates) Ebola (bush meat? ) SARS (civet cat? )

Incidence of BSE in UK, 1987 -99 (c. 180 K cases) 1988/9 bans: Sale of nervous tissue and offal for human consumption Eating cattle >30 months old Mammalian products in ruminant feed BUT: no ban on feed for swine or poultry Human v. CJD (end 2003) -- 125 cases: UK-117, France-6, Ireland-1, Italy-1

Nipah Viral Encephalitis, in Malaysia 01/97 Farm worker hospitalized with viral encephalitis (VE). 10/97 First death (pig-farm worker) from VE. 02/98 3 farm workers develop VE. 11/98 Health Minister declares it ‘Japanese Encephalitis’ mosquito control and vaccine program. But outbreak spreads. 1 -2/99 Pig farmers begin ‘fire sales’ of pigs. Outbreak recedes a little. 02/99 Laboratories receive first samples of infected human tissue. “New” virus? Mass pig culling begins. Villagers flee. 03/99 Virus isolated and identified with reagents used to characterize Hendra virus (a recently-identified horse virus, from Queensland). 04/99 ‘Nipah virus’ discovery announced. Culling continues. 05/99 WHO declares outbreak over (265 cases, 40% fatal). 02/00 Last death. Fruit bats (flying foxes) deemed the likely reservoir.

Travel and Trade: examples Aedes albopictus mosquito eggs in shipments of used tyres dengue fever Long-distance travel; wild animal trade HIV/AIDS West Nile Virus (New York City, 1999) SARS, 2003

SARS Severe Acute Respiratory Syndrome A genetic model for the Coronavirus family. (Photo: J Oxford, Retroscreen Virology Ltd)

Key wildlife trade routes in SE Asia and China Lao PDR Vietnam Cambodia

Environmental Changes Land use, forest clearance Biodiversity losses, extinctions Dams, irrigation Climate change

Density of An. darlingi (malaria vector) in Peruvian Amazon An. Darlingi abundance (log scale) No. of survey sites = 2433 Secondary (deforested) growth Village Farm Forest Patz et al, 2003

Lyme Disease: Influences of Habitat Fragmentation & Biodiversity Loss High Lyme Disease risk Woodland suburban housing (NE USA) High tick density and high tick infection prevalence infected deer Complex life- Expanding mouse populations cycle of tick Less diversity of vertebrate predators and viral hosts Forest fragmentation, hunting (wolves, passenger pigeons) Many competent reservoir species less dilution by incompetent reservoir species Poor inter-species regulation Adapted from: R. Ostfeld

Climate Change and Infectious Disease Some recent changes in ID patterns may reflect the influence of climate change (debate continues) Tick-borne encephalitis (north spread in Sweden) Cholera in Bangladesh (strengthening relationship with El Niño events) Malaria ascent in east African highlands Time-trends in incidence of (reported) food poisoning, esp. Salmonellosis

Dengue Fever: Estimated geographic region suitable for maintenance of Ae. aegypti, under alternative climate scenarios for 2050 . . Darwin Katherine . Darwin . Katherine . Broome . Port Headland . . Townsville . . Mackay Rockhampton . . Darwin Brisbane Katherine . Broome . Port Headland . Carnarvon NCEPH/CSIRO/Bo. M/Univ. Otago, 2003 . Risk region under medium emissions scenario, 2050 Carnarvon Mackay Current risk region for dengue Townsville Port Headland Cairns . . Cairns Broome . . Cairns Townsville . . Mackay Rockhampton Risk region under high emissions scenario, 2050

MALARIA IN ZIMBABWE, UNDER CLIMATE CHANGE Source: Kris Ebi Baseline 2000 2025 2050 2075 2100

Source: Kris Baseline 2000 2025 2050 2075 2100 Ebi

Summary Humans, domestic animals and wildlife are inextricably linked by epidemiology of infectious diseases (IDs). IDs will continue to emerge, re-emerge and spread. Human-induced environmental changes, inter-species contacts, altered social conditions, demography and medical technology affect microbes’ opportunities. Also: New research, technology and collaborative networks will also elucidate role of infection in diverse, mostly chronic, diseases of unknown cause. .

INFECTIOUS CAUSES OF CHRONIC DISEASE: Examples Disease Cause Cervical cancer Chronic hepatitis, liver cancer Lyme disease (arthritis) Whipple’s disease Bladder cancer Stomach cancer Peptic ulcer disease Human papilloma virus Hepatitis B and C viruses Borrelia burgdorferi Tropheryma whippelii Schistosoma haematobium Helicobacter pylori Atherosclerosis (CHD) Diabetes mellitus, type 1 Multiple sclerosis Inflammatory bowel disease Chlamydiae pneumoniae Enteroviruses (esp. Coxsackie) Epstein-Barr v, herpes vv? Mycobacterium avium sub-spp. Paratuberculosis, Yersinia

Conclusion I: Understanding what promotes human-microbe contacts (i) Intensified modification/exploitation of natural environments and food production. (ii) Disturbance of natural ecosystems and their various internal biotic controls. (iii) Poverty, crowding, social disorder, mobility and political instability.

Conclusion II: Microbes as Co-Habitants Microbes’ interest is in survival and reproduction. They have no malign intent; morally neutral! Their evolution-based drive to survive is as strong as ours (and draws on much longer experience).

That’s all, folks

Cyclone Sid: Precursor to 1998 Japanese Encephalitis incursion? Air trajectories @ 100 m altitude 27 Dec 1997: Tropical Cyclone Sid Backwards trajectory analysis of JE