Recent Awareness of How Human Activities and Land-uses are Linked to Human

Health and Disease Transmission among Humans

and Animals

Story by AM/CLH , Photo by ANWAR MIRZA, REUTERS NEWS PICTURE SERVICE

Hong Kong kills 8,300 chickens as bird flu found CHINA: February 3, 2003

Ban on importing or exporting meat because of mad cow disease

Evelyn Hockstein/Polaris, for The New York Times

Soldiers in Uíge wore biohazard suits while burying two bodies even though dead not known to have Marburg virus.

Stalking a Deadly Virus, Battling a Town's FearsBy SHARON LaFRANIERE and Denise Grady; April 17, 2005 – New York Times

Evelyn Hockstein/Polaris, for The New York Times

Health workers decontaminate body - died due to Marburg virus & wrapped it in a protective shroud.

Vietnamese Boy Disabled by Agent Orange in a Ho Chi Minh City Hospital VIETNAM : February 28, 2005

A Vietnamese boy disabled by Agent Orange gets the attention of a volunteer while sitting in his cot in a Ho Chi Minh City hospital, February 25, 2005.

“On Monday, a New York court will begin hearing a lawsuit brought by more than 100 Vietnamese seeking compensation and a clean-up of contaminated areas from more than 30 firms, among them Dow Chemical Co and Monsanto Co, the largest makers of Agent Orange. Agent Orange, named after the colour of its containers, is blamed for nightmarish birth defects in Vietnam where babies appeared with two heads or without eyes or arms.” Story by Adrees Latif AL/CCK, Photo by ADREES LATIF, REUTERS

NEWS PICTURE SERVICE

Forests and Human Health

1. Human Health links to Forests

2. Introduction – complex factors interlinked to disease

3. Factors accelerating the spread of contagious diseases

4. Two Case Studies – show forest link to disease

Leading causes of deaths (1997)

Link between forests and source of disease? Insect vectors very adaptable to human social systems. Used to be adapted to forest

environment and bred in tree holes but now discarded tires, drains, water cans

Aids

eg Tuberculosis

1997 data

Important in Forests, tropics

FORESTS IMPORTANT?

Deforestation causes insect vectors to move to cities

Factors accelerating spread of contagious diseases: Global Factors

• High human population densities

• Poor sanitary conditions - contact with water, food contaminated with human waste

• Speed, frequency of modern travel

• Use of excess chemicals (fertilizers, pesticides, etc) against insect vectors, increase growth of food crops

• Climate change, climatic events

Forests and Human Health

Introduction – complex factors interlinked to disease

Genetics – Environment –

Nutrition – Social – Political

factors - Resource uses

Nutrition, Food Security, Poverty = Human Health

• Food security - inability to obtain sufficient food on a day-to-day basis

• Higher incidence of infectious diseases when undernourished - can’t afford medicine or medicine not available

• Poverty greatest threat to food security & human health

• A poor environment will contribute to a poor diet and negatively affect nutrition

• Poor nutrition may contribute to diseases & their emergence

USDA FoodPyramid

High Health = Low Sickness

Eating a Balanced Diet

What nourishment exists from eating monkeys?Central Africa eat primates when antelopes are scarce.

BUT this is food in many parts of the world if you are fortunate

In tropics, 50% of protein consumed by people from bushmeat

& war stops agriculture so more dependent on bushmeat

When and what in forests contribute to

Human health problems?

Forests and Human Health –link is human behavior in landscape

Factors accelerating spread contagious diseases

• Global factors – people, sanitary conditions, travel, chemical uses, climate change

• Land use changes

• Moving into or through interior, remote forest areas – close contact humans to wildlife

• Wars - Hunting for bushmeat, selling animal parts for medicinal purposes

- climate determines insect outbreaks (eg malaria, dengue fever)

•Temperature = Insects sensitive to climate - affects timing, intensity of outbreaks (minimum air temp 15-18C needed for development of malaria parasite, threshold temps >20C set off epidemic) [what is average room temperature??]

•Drought (combined with AIDS, poverty, war, bad governments, corruption) – extreme starvation > poor health > higher disease susceptibility

Factors accelerating spread of contagious diseases: Global Factors

CLIMATIC EVENTS- climate determines insect outbreaks

•Higher rainfall = more malaria outbreaks in world with more rain & increases in night time temperatures during El Nino

- El Nino 1987, malaria increased significantly in Rwanda- El Nino 1997/98 worst in history with torrential rains in East Africa – malaria epidemics in Uganda highlands

Factors accelerating spread of contagious diseases: Land Use Changes

•Deforestation

•Replace forests with crop farming, ranching and small animals

•Which vegetation regrows after deforestation

•Water bodies in disrupted areas

•Road construction

•Mining

WHY affect health?

- Creates supportive habitat for parasites & their vectors, increase spread disease organisms = (cattle, pigs, chickens serve as host for

disease)

Forests:•heavily shaded

•not have free standing water (thick organic layers on ground) so few breeding ground for mosquitoes

•Trees adapted to get rid of excess water

Cleared land:•more sunlight

•prone to water puddles

•crops (sugar cane, rice) use of irrigation ditches – good breeding habitats

Why extensive deforestation in tropics affect disease spread and its vectors?

DEFORESTATION:

- most disruptive change affecting parasitic vector populations. Exposed ground becomes great breeding habitat for mosquitoes (e.g. increase in incidence of malaria)

Malaysia – 50 year repeat growing of rubber had cyclic malaria epidemics

Trinidad – 1940s cut forests, trees came back with lots bromeliads in canopy (hold water and preferred breeding site of malaria mosquitoes).- Removal bromeliads, malaria prevalence decreased

Replacement of forests with rubber plantations or other vegetation

Aechmea chantinii (Leinbach)

http://www.charlies-web.com/bromeliads-alphalist/tex365.html

Aechmea nidularioides

Frogs die and fertilize plants but also mosquitoes use as breeding ground

ROADS

Road Construction into previouslyinaccessible forests:

•Erosion, create ponds – breeding sites disease vectors

•Roads allow construction workers, loggers, miners, tourists, conservationists to travel to new areas – expose new diseases (no immunity like forest dwellers); animals –exposed to new diseases

http://www.webshots.com/explains/outdoors/indian-ocean.html Bali`s rice fields...published by nature4u2 in scenery & nature on 2001-07-31 last update on 2003-04-29

http://www.delange.org/TucumePyramids/TucumePyramids.htm

http://it.inmagine.com/agriculture-immagini-photos/pixtal-pt055

STANDING POOLS OF WATER – GREAT HABITAT FOR MOSQUITOES

- increase contact between wildlife and humans in interior forest areas (e.g. increase Ebola, AIDS)

Factors accelerating spread of contagious diseases: Moving into or through interior, remote forest areas – close contact humans to wildlife

Forest dwellers immune but NOT OUTSIDERS

• economic development (mining, timber, water for hydro electric plants, irrigation), legal/illegal trade, drugs moving people with no immunity into regions

• Outsiders exposed to new diseases from contact with animals or changing land-uses

Interior, remote forest areas:

forest dwellers no immunity to new diseases from outside regions

Wars – factors accelerating spread disease• Decrease food security and people’s health in

general which makes people more susceptible to diseases and premature death

• Resettling people or people spontaneously migrating. Example Indonesia, resettling people from densely populated islands of Java and Bali to more sparsely populated and densely forested outer island where people not have immunity to malaria and where the plasmodium thrive in conditions created by the development project (Prothero 1999).

• Most people who move are poorly educated and do not know how to protect themselves against malaria and other health risks (Prothero 1999)

Humans are also dangerous to the Health of Forest Animals!!

Human contact with animals makes animals

sick!!!!

Polio-like virus epidemic spread from a village; 15 chimpanzees severely crippled or died in 1960s, Tanzania

Polio like virus & flu like epidemic killed 11 chimpanzees in Democratic Republic of Congo, 2003

Great Apes - Documented outbreaks of scabies, intestinal parasites, yaws (syphilis-like), respiratory infections similar to measles from human contacts- Ebola has killed up to 90% of the apes in central Africa

Outbreaks of disease in chimpanzees, great apes of human origin:

Illnesses in villages next to Park (% people with symptoms), Kibale National Park, Uganda:

Fever = 82%Coughing = 64%Respiratory distress = 26%Diarrhea = 24%Vomiting = 24%General Illness = 22%

Outbreaks of disease in chimpanzees, great apes of human origin :

International Gorilla Conservation Programme ask tourists:

•Keep minimum distance between tourists and gorillas at 5 to 7 m

•Use facemasks reduce transmission airborne diseases

•Prior to visit, tourists wash hands & disinfect feet

•Construct adequate pit latrines so proper disposal human wastes

•Refuse tourists entry if sick

Two Case Studies – show forest link to disease

• Malaria, forests, environmental change and people (All 4 impact: climate change, land use change, people moving into remote forest areas, wars)

• Acorns, white footed mouse/deer, ticks, bacteria, Lyme disease, forest fragmentation (impact: land use change – others less relevant)

Malaria, forests, environmental change, people

Malaria originated in Africa – fossils of mosquitoes 30 million years old; Plasmodium parasites highly specific - man only vertebrate host, Anopheles mosquitoes as vectors (parasite specificity - long, adaptive relationship with humans)

Commonly called “forest malaria”•Reasons where found – year round rainfall, temperatures where mosquitoes breed continuously

•Forests fringes – most malarious where ecological conditions favor disease

In 1990, 80% cases in Africa, remainder clustered in nine countries: India, Brazil, Afghanistan, Sri-Lanka, Thailand, Indonesia, Vietnam, Cambodia, China.

The map indicates current distribution of indigenous malaria according to WHO http://www.wehi.edu.au/MalDB-www/intro.html

Malaria in 91 countries

NOTE WHERE FOUND! ARE THERE NO MOSQUITOES IN THE NORTHERN LATITUDES (BOREAL FORESTS, TUNDRA)?

????

Anopheles Mosquitos - http://www.wehi.edu.au/MalDB-www/intro.html

•TODAY Malaria endemic to tropics, with extensions into subtropics but 18th century North America had malaria in lowland forests but eradicated it

•Malaria spread by travelers flying - cause death in non-malarious areas.

Heliconia – high abundance after agriculture abandonment in American tropics

Building Panama Canal, found linked to incidence of malaria since good mosquito breeding ground

Left, United Nations; Corbis

Use of DDT works as an insecticide to control but conflicts over other effects of DDT even though DDT only effective control of mosquitoes

Control measures:

spraying with DDT

coating marshes with paraffin

draining stagnant water

Preventive Measures:

Safest anti-malarial drug (chloroquine) no longer works as well since malaria parasite becoming immune

The top photograph of a Unicef spraying with DDT in Paraguay was exhibited at the 1964-65 World's FairUnicef; Ian Berry/Magnum

Bottom picture, assault on mosquitos -- without DDT -- in Burundi in 2003

Unicef; Ian Berry/Magnum

Lyme Disease

Acorns

White footed mouse/deer

Ticks

Bacteria

Forest fragmentation

- a case study not mainly in the tropics but found globally and significant in the temperate region (becoming big concern even in western US)

Lyme Disease

Slide 32

Center for Disease Control and Prevention = 17,730 cases Lyme disease in 2000; Disease found in 44 states, only 6 free from Lyme disease

HUMANS and Lyme disease =

Fatigue

Sore joints

Heart damage

Arthritis

Memory loss

White footed mouse http://animaldiversity.ummz.umich.edu/media/phil/pln1.jpg

White Oak acorns http://www.bowsite.com/bowsite/features/armchair_biologist/acorns/acorns.html; http://www.bartelart.com/acorn.htm

Animals, trees, people health all connected to Lyme disease

Deer and mice are hosts for bacteria

                                   

Acorn masting high every 2-5 years in oaks

High food for mouse – increase their #s

http://lucas.osu.edu/gm/tufc.htm, White footed mouse http://animaldiversity.ummz.umich.edu/media/phil/peromyscus_leucopus_37.jpg

Gypsy Moth – an invasive introduced silk making in US, great mouse food

                                   

More food = MORE MICE

Ticks have more animals to bite to get blood = # ticks increases

More ticks with bacteria causing Lyme

Ticks bite humans – Lyme disease

#1

#2

#3

Ticks

Allan et al. 2002

Small forest patch (< 3 acres)

Large forest patch > 3 acres

                

WHY DOES FOREST SIZE AFFECT INCIDENCE OF LYME DISEASE?

White-footed mouse - at home in forest, field, your house

http://encarta.msn.com/encnet/refpages/RefMedia.aspx?refid=461517523&artrefid=761565627&sec=-1&pn=1

Loss of predators (foxes, weasels)

Loss of competitors (chipmunks, squirrels)

No controls on populations so increase esp. forest patch < 5 acres

Both plans provide 36 home

sites, Which better for ticks?

Conventional development strategy worst for ticks, Lyme disease when forest tract cut up into small pieces with lawnsBetter - cluster houses in large area of undeveloped forest

Conventional Subdivision

Cluster Housing (Open-Space Zoning)

http://www.sefut.uni-freiburg.de/bilder/Nassreisanbau.pdf

Future drivers of Deforestation

- most disruptive change affecting parasitic vector populations. Exposed ground becomes great breeding habitat for mosquitoes (e.g. increase in incidence of malaria)

- increase contact between wildlife and humans in interior forest areas (e.g. increase Ebola, AIDS)