environment change and health iii

8/8/2019 Environment Change and Health III

1/79

ENVIRONMENT AND HUMAN HEALTH


2/79

Why to study environment and human health

Climate change is already happening

and represents one of the greatest

environmental, social and economicthreats facing the planet.


3/79

Aflatoxins has been identified as risk factors for

developing liver cancer in people infected with

hepatitis B virus_ (EHP 118:818-824 Liu and Wu) Study shows association between psychological

stress and adverse physiological effects from

exposures to air pollution (EHP 118:769-775;

Clougherty etal)

Chlorine gas released in Shivari, 3 died 60

affected


4/79

Why to study environment and human health

Public health problems caused by environmental contaminationand emerging infectious diseases are a growing concernworldwide.

These public health threats are affected by the relationship

between people and the physical, chemical, and biologicalnature of our natural environments.

Population growth and the associated pressures ofdevelopment are increasing the difficulties associated withsustaining effective public health practices and policies.

Vector-borne disease, water contamination, airbornecontaminants, bioaccumulation of contaminants in the food

chain, and environmental threats to public health the world overrequire marshalling of all our scientific knowledge and know-how to develop new solutions.

Understanding environmental and ecological health is aprerequisite to protecting public health.


5/79

Environmental health is the branch of

public health that is concerned with all

aspects of the natural and builtenvironment that may affect human

health. Other terms that concern or refer

to the discipline of environmental health

include environmental public healthand environmental health and

protection.


6/79

Environmental health is defined by

the World Health Organization as:

Those aspects of the human body human health anddisease that are determined by factors in theenvironment. It also refers to the theory and practice of

assessing and controlling factors in the environment thatcan potentially affect health.

Environmental health as used by the WHO RegionalOffice for Europe, includes both the direct pathologicaleffects ofchemicals, radiation and some biologicalagents, and the effects on health and wellbeing of the

broad physical, psychological, social and aestheticenvironment which includes housing, urban development,land use and transport


7/79

Environmental health services aredefined by the World HealthOrganization as:

implement environmental health policiesthrough monitoring and control activities.

promoting the improvement ofenvironmental parameters and byencouraging the use of environmentallyfriendly and healthy technologies

They also have a leading role indeveloping and suggesting new policyareas.


8/79

"Scope of practice in environmental health" means the practiceof environmental health by registered environmental healthspecialists in the public and private sector within the meaning of

this article and includes, but is not limited to, organization,management, education, enforcement, consultation, andemergency response for the purpose of prevention ofenvironmental health hazards and the promotion and protectionof the public health and the environment in the following areas:food protection; housing; institutional environmental health; landuse; community noise control; recreational swimming areas andwaters; electromagnetic radiation control; solid, liquid, and

hazardous materials management; underground storage tankcontrol; on-site septic systems; vector control; drinking waterquality; water sanitation; emergency preparedness; and milkand dairy sanitation.

The environmental health profession had its modern-day rootsin the sanitary and public health movement of the UnitedKingdom. This was epitomized by Sir Edwin Chadwick, who

was instrumental in the repeal of the poor laws and was thefounding president of the Association of Public SanitaryInspectors in 1884, which today is the Chartered Institute ofEnvironmental Health.


9/79


10/79


11/79

INTRODUCTION

Large-scale and global environmental hazards to humanhealth include climate change, stratospheric ozonedepletion, loss of biodiversity, changes in hydrological

systems and the supplies of freshwater, land degradationand stresses on food-producing systems.

Appreciation of this scale and type of influence on humanhealth requires a new perspective which focuses onecosystems and on the recognition that the foundationsof long-term good health in populations rely in great part

on the continued stability and functioning of thebiosphere's life-supporting systems. It also brings anappreciation of the complexity of the systems upon whichwe depend.


12/79

CHART


13/79

CHART


14/79

Climate Change and Human

Health

Climate change is a significant and emerging threat to public health,and changes the way we must look at protecting vulnerable populations.

The most recent report of the Intergovernmental Panel on ClimateChange confirmed that there is overwhelming evidence that humans areaffecting the global climate, and highlighted a wide range of implications

for human health. Climate variability and change cause death and disease through natural

disasters, such as heat waves, floods and droughts.

The impacts of climate on human health will not be evenly distributedaround the world. Developing country populations, particularly in SmallIsland States, arid and high mountain zones, and in densely populatedcoastal areas, are considered to be particularly vulnerable.

Fortunately, much of the health risk is avoidable through existing healthprogrammes and interventions. Concerted action to strengthen keyfeatures of health systems, and to promote healthy developmentchoices, can enhance public health now as well as reduce vulnerabilityto future climate change.


15/79

Biodiversity

There is growing concern about the healthconsequences of biodiversity loss and change.An important consequence for humans is the

disruption of ecosystems that provide nature'sgoods and services. Biodiversity loss alsomeans that we are losing, before discovery,many of nature's chemicals and genes, of thekind that have already provided humankind withenormous health benefits. There are also well

founded concerns about the need tounderstand and assess the impacts of modernfood biotechnology on human health.


16/79


17/79


18/79

Stratospheric ozone depletion,

UV radiation and health

It has been recognized for several decades that therelease of chlorofluorocarbons and other atmosphericpollutants depletes stratospheric ozone, which in turnincreases human exposure to ultraviolet radiation,

causing skin cancer and cataracts. The recognition of direct effects on human health effects

was a major stimulus to the Montreal Protocol, whichacts to reduce emissions of pollutants that weaken theozone layer. Although this international agreement isproving highly effective in reducing risks in the longterm, UV radiation remains a health hazard.

The World Health Organization, and partnerorganizations - through the Intersun project - havedeveloped and promote the UV Index, a tool to informand educate the public about sun protection


19/79

Changing patterns of

diseases Despite a century of often successful prevention and

control efforts, various different diseases remain animportant global problem in public health, causing over13 million deaths each year. Changes in society,technology and the microorganisms themselves arecontributing to the emergence of new diseases, the re-emergence of diseases once controlled, and to thedevelopment of antimicrobial resistance. The area ofspecial concern in the twenty-first century is diseases dueto change in environment and its antimicrobialresistance. The effective control of diseases in the newmillennium will require effective public healthinfrastructures that will rapidly recognize and respond tothem and will prevent emerging problems


20/79

contd

Emerging diseases pose important public health problems forboth the developed and developing world. Many new orpreviously unrecognized bacterial, fungal, viral, and parasiticdiseases have emerged within the past two decades. At the

same time, many once-controlled infections have re-emerged orbecome resistant to antimicrobial therapy. This emergence isthe result of changes in society, technology, the environment,and the microbes themselves, and these changes have had oftenunpredictable consequences. Important factors influencingemergence include changes in human demographics andbehaviour, changes in technology and industry, changes ineconomic development and land use, increasing and rapid

international travel and commerce, microbial adaptation andchange, and the breakdown of public health measures.Addressing emerging infectious diseases will requireinternational and interdisciplinary partnerships to build anappropriate infrastructure to detect and respond to these oftenunanticipated threats to health.


21/79

Health

Throughout the world, the prevalence of some diseases andother threats to human health depend largely on local climate.Extreme temperatures can directly lead to loss of life, whileclimate-related disturbances in ecological systems, such as

changes in the range of infective parasites, can indirectly impactthe incidence of serious infectious diseases. In addition, warmtemperatures can increase air and water pollution, which inturn harm human health.

Human health is strongly affected by social, political, economic,environmental and technological factors, includingurbanization, affluence, scientific developments, individualbehavior and individual vulnerability (e.g., genetic makeup,

nutritional status, emotional well-being, age, gender andeconomic status). The extent and nature of climate changeimpacts on human health vary by region, by relativevulnerability of population groups, by the extent and durationof exposure to climate change itself and by societys ability toadapt to or cope with the change.


22/79


23/79

Although links between exposures to environmental

contaminants and health impacts have been known for

centuries, recent research documents an expanding list of

previously unrecognized effects after fetal or infant exposures

The developing fetus and child are particularly vulnerable to

toxic insults.

children are often disproportionately exposed to toxic

environmental agents

lead, mercury, or polychlorinated biphenyls (PCBs) canpermanently damage the developing brain of a child

Early exposures to dioxin or polychlorinated biphenyls (PCBs)

damages the developing immune system

Risks of asthma and high blood pressure are increased by early

environmental exposures

Recent research from Sweden concludes not only thatenvironmental factors play a more important role than genetic

inheritance in the origin of most cancers, but also that cancer

risk is largely established during the first 20 years of life


24/79

Technological developments have dramatically reducedmortality resulting from many diseases.

In many instances, however, disease incidence is increasing,

although for some conditions without standardized trackingmechanisms, trends are difficult to determine accurately.

The burden from current patterns of disease and disability isenormous and extracts a terrible toll from individuals, families,and communities.

Nearly 12 million children in the U.S (17 percent) suffer fromone or more developmental disabilities,

Learning disabilities alone affect 5 to 10 percent of children inpublic schools, and these numbers appear to be increasing

The age-adjusted incidence of melanoma, lung (female),prostate, liver, non-Hodgkin's, thyroid, kidney, breast, brain,bladder cancers has steadily increased over the past 25 years.

Some birth defects, including disorders of the male reproductivesystem and some forms of congenital heart disease, are

increasingly common Sperm counts and fertility are in decline in some areas of the

U.S. and other parts of the world.

Asthma is more common and more severe than ever before

improved understanding of development of the brain and theimmune, reproductive, respiratory, and cardiovascular systemsleads to the conclusion that other environmental factors play a

major role in determining current patterns of disease.


25/79

To the limited degree that health care providers addressenvironmental factors at all

These are more easily addressed by individuals thanmore complex problems like air and water pollution,hazardous waste sites, agricultural systems thatinevitably result in farm worker pesticide exposures, andmercury contamination of dietary fish.

Global environmental conditions, however, are changing,along with the changing pattern of disease and disability,and our increasing understanding of the importance ofenvironmental factors in determining the health ofindividuals and populations places a new and specialresponsibility on the medical profession.


26/79


27/79

FigureA shows the location of the respiratory structures in the body. Figure B is an

enlarged image of airways, alveoli, and the capillaries. Figure C shows the locationof gas exchange between the capillaries and alveoli


28/79

respiratory system The respiratory system is a group of organs responsible for

carrying oxygen from the air to the bloodstream and expellingthe waste product carbon dioxide. The main parts of this systemare the airways, the lungs and linked blood vessels, and themuscles that enable breathing.

Airways

The airways are passages that carry oxygen-rich air to thelungs and carbon dioxide out of the lungs. The airways includethe:

Nose and linked air passages called nasal cavities

Mouth

Larynx, or voice box Trachea, or windpipe

Tubes called bronchial tubes orbronchi, and their branches,called bronchioles


29/79

Air first enters the body through the nose or mouth, which wetsand warms the air. (Cold, dry air can irritate the lungs.) The air

then travels through the larynx box and down the trachea. Thetrachea divides into two bronchi that enter the lungs.

A thin flap of tissue called the epiglottis covers the tracheawhen a person swallows. This prevents food or drink fromentering the air passages that lead to the lungs.

Except for the mouth and some parts of the nose, all of the

airways have special hairs called cilia that are coated with stickymucus. The cilia trap germs and other foreign particles thatenter the airways when a person breathes in air.

These fine hairs then sweep the particles up to the nose ormouth. There, they are swallowed, coughed, or sneezed out ofthe body. Nose hairs and mouth saliva also trap particles and

germs.


30/79

Lungs and blood vessels

The lungs and linked blood vessels deliver oxygen to the body andremove carbon dioxide. The lungs lie on either side of the sternum(breastbone) and fill the inside of the chest cavity. The left lung isslightly smaller than the right lung to allow room for the heart.

Within the lungs, the bronchi branch into thousands of smaller, thinnertubes called bronchioles. These tubes end in bunches of tiny round airsacs called alveoli.

Each of these air sacs is covered in a mesh of tiny blood vessels called

capillaries. The capillaries connect to a network ofarteries and veinsthat move blood through the body.

The pulmonary artery and its branches deliver blood rich in carbondioxide (and lacking in oxygen) to the capillaries that surround the airsacs. Inside the air sacs, carbon dioxide moves from the blood into theair. Oxygen moves from the air into the blood in the lungs.

The oxygen-rich blood then travels to the heart through the pulmonary

vein and its branches. The heart pumps the oxygen-rich blood out to thebody.

The lungs are divided into five main sections called lobes. Some peopleneed to have a diseased lung lobe removed. However, they can stillbreathe well using the rest of their lung lobes.


31/79

Bronchitis can be classified as either acute or chronic.Acute bronchitis can be defined as acute bacterial or viral

infection of the larger airways in healthy patients with nohistory of recurrent disease

It affects over 40 adults per 1000 each year and consistsof transient inflammation of the major bronchi andtrachea. Most often it is caused by viral infection andhence antibiotic therapy is not indicated in immunocompetent individuals. [

Acute Exacerbations of Chronic Bronchitis (AECB) arefrequently due to non-infective causes along with viralones. 50% of patients are colonised with Haemophilusinfluenzae, Streptococcuspneumoniae orMoraxellacatarrhalis

Antibiotics have only been shown to be effective if all

three of the following symptoms are present:- increaseddyspnoea, increased sputum volume and purulence. Inthese cases 500 mg ofAmoxycillin orally, every 8 hoursfor 5 days or 100 mg doxycycline orally for 5 days shouldbe used.[2]


32/79

Pneumonia is a serious infection of the small bronchiolesand alveoli that can involve the pleura. It occurs in avariety of situations and treatment must vary according tothe situation.

It is classified as either community or hospital acquired

depending on where the patient contracted the infection. The most common treatment is antibiotics and these vary

in their adverse effects and their effectiveness.

Pneumonia is also the leading cause of death in childrenless than five years of age.

The most common cause of pneumonia is pneumococcal

bacteria, Streptococcus pneumoniae accounts for 2/3 ofbacteremic pneumonias.

A dangerous type of lung infection with a mortality rate ofaround 25%.


33/79


34/79

Waterborne diseases Waterborne diseases are caused by pathogenic

microorganisms which are directly transmitted whencontaminated fresh water is consumed.

Contaminated fresh water, used in the preparation offood, can be the source offoodborne disease throughconsumption of the same microorganisms.

According to the World Health Organization, diarrhealdisease accounts for an estimated 4.1% of the total andis responsible for the deaths of 1.8 million people everyyear.

It was estimated that 88% of that burden is attributable to

unsafe water supply, sanitation and hygiene, and ismostly concentrated in children in developing countries.

Waterborne disease can be caused by protozoa, viruses,orbacteria, many of which are intestinal parasites.


35/79

Disease and

TransmissionMicrobial Agent Sources of Agent in Water Supply General Symptoms

Amoebiasis(hand-to-

mouth)

Protozoan

(Entamoebahistolytica)

(Cyst-like

appearance)

Sewage, non-treated drinking water, flies in water

supply

Abdominal discomfort, fatigue, weight

loss, diarrhea,bloating, fever

Cryptosporid

iosis (oral)

Protozoan

(Cryptosporidiu

m parvum)

Collects on water filters and membranes that cannot

be disinfected, animal manure, seasonal runoffof

water.

Flu-like symptoms, watery diarrhea, loss

of appetite, substantial loss of weight,

bloating, increased gas, nausea

Cyclosporias

is

Protozoan

parasite

(Cyclospora

cayetanensis)

Sewage, non-treated drinking watercramps, nausea, vomiting, muscle aches,

fever, and fatigue

Giardiasis

(oral-fecal)(hand-to-

mouth)

Protozoan

(Giardia

lamblia) Mostcommon

intestinal

parasite

Untreated water, poor disinfection, pipe breaks, leaks,

groundwatercontamination,campgroundswherehumans and wildlife use same source of water.

Beavers and muskrats createponds that act as

reservoirs for Giardia.

Diarrhea, abdominal discomfort,bloating, and flatulence

Microsporidi

osis

Protozoan

phylum

(Microsporidia

The genera ofEncephalitozoon intestinalishas been

detected in groundwater, the origin of drinking water[3]

Diarrhea and wasting in

immunocompromised individuals


36/79

Disease and

TransmissionMicrobial Agent Sources of Agent in Water Supply General Symptoms

Schistosomiasis

(immersion)Members of the genus Schistosoma

Fresh water contaminated with certain

types of snails that carry schistosomes

Rash or itchy skin.

Fever, chills, cough, and

muscle aches

Dracunculiasis (Guinea

Worm Disease)Dracunculus medinensis Stagnant water containing larvae

Allergic reaction,urticaria rash, nausea,

vomiting, diarrhea,

asthmatic attack.

Taeniasis Tapeworms of the genus Taenia Drinking water contaminated with eggs

Intestinal disturbances,

neurologic

manifestations, loss of

weight, cysticercosis

Fasciolopsiasis Fasciolopsis buskiDrinking water contaminated with

encysted metacercaria

GIT disturbance,diarrhea, liver

enlargement, cholangitis,

cholecystitis, obstructive

jaundice.

Hymenolepiasis (Dwarf

Tapeworm Infection)Hymenolepis nana Drinking water contaminated with eggs

Abdominal pain,

anorexia, itching around

the anus, nervous

manifestation

Echinococcosis (Hydatid

disease)Echinococcus granulosus

Drinking water contaminated with feces

(usually canid) containing eggs

Liver enlargement,

hydatid cysts press on

bile duct and blood

vessels; if cysts rupture

they can cause

anaphylactic shock

coenurosis multiceps multiceps contaminated drinking water with eggsincreases intacranial

tension


37/79

Disease and

Transmissio

n

Microbial AgentSources of Agent in Water

SupplyGeneral Symptoms

Botulism Clostridium botulinum

Bacteria can enter a wound

from contaminated water

sources. Can enter thegastrointestinal tract by

consuming contaminated

drinking wateror (more

commonly) food

Dry mouth,blurred and/ordouble vision,muscle weakness, difficulty breathing, slurred speech, vomiting

and sometimes diarrhea.

Campylobac

teriosis

Most commonly caused by

Campylobacter jejuni

Drinking water contaminated

with feces

Produces dysentery like symptoms along with a high fever.

Usually lasts 210 days.

CholeraSpread by the bacterium

Vibrio cholerae


with the bacterium

In severe forms it is known to be one of the most rapidly fatal

illnesses known. Symptoms include very watery diarrhoea,

nausea, cramps, nosebleed, rapidpulse, vomiting, and

hypovolemic shock(in severe cases), at which point death can

occur in 1218 hours.

E. coli

Infection

Certain strains of

Escherichia coli

(commonlyE. coli)

Water contaminated with the

bacteria

Mostly diarrhea. Can cause death in immunocompromised

individuals, the very young, and the elderly due to dehydration

from prolonged illness.

M. marinum

infectionMycobacterium marinum

Naturally occurs in water,

most cases from exposure in

swimming pools or more

frequently aquariums; rare

infection since it mostly

infects immunocompromised

individuals

Symptoms include lesions typically located on the elbows, knees,

and feet (from swimming pools) or lesions on the hands

(aquariums). Lesions may be painless or painful.


38/79

Dysentery

Caused by a number of

species in the genera

Shigella and Salmonella

with the most common

being Shigella

dysenteriae

Water contaminated

with the bacterium

Frequent passage offeces withblood and/ormucus and in

some cases vomiting of blood.

Legionellosis (two

distinct forms:

Legionnaires disease

and Pontiac fever)

Caused by bacteria

belonging to genus

Legionella (90% of cases

caused byLegionella

pneumophila)

Contaminated water:

the organism thrives in

warm aquatic

environments.

Pontiac fever produces milder symptoms resembling acute

influenzawithoutpneumonia. Legionnaires disease has

severe symptoms such as fever, chills, pneumonia (with

cough that sometimes produces sputum), ataxia, anorexia,

muscle aches, malaise and occasionally diarrhea andvomiting

LeptospirosisCaused by bacterium of

genusLeptospira

Water contaminated by

the animal urinecarrying the bacteria

Begins with flu-like symptoms then resolves. The second

phase then occurs involving meningitis, liverdamage(causesjaundice), and renal failure

Otitis Externa

(swimmers ear)

Caused by a number of

bacterial and fungal

species.

Swimming in water

contaminated by the

responsible pathogens

Ear canal swells causing pain and tenderness to the touch


39/79

Salmonellosis Caused by many bacteria ofgenus Salmonella


with the bacteria. More common

as a food borne illness.

Symptoms include diarrhea,

fever, vomiting, and abdominal

cramps

Typhoid fever Salmonella typhi Ingestion of water contaminatedwith feces of an infected person

Characterized by sustained

fever up to 40C (104F),

profuse sweating, diarrhea, less

commonly a rash may occur.

Symptoms progress to delirium

and the spleen and liverenlarge

if untreated. In this case it can

last up to four weeks and cause

death.

Vibrio Illness

Vibrio vulnificus, Vibrio

alginolyticus, and Vibrio

parahaemolyticus

Can enterwounds from

contaminated water. Also got by

drinking contaminated water or

eating undercooked oysters.

Symptoms include explosive,

watery diarrhea, nausea,

vomiting, abdominal cramps,

and occasionally fever.


40/79


41/79

Cholera

In India, it's common among children ages 1 to5, but in other endemic areas, it's equallydistributed among all age-groups.

Causes ofCholera

The most common cause of cholera is: It is caused by a germ known as Vibrio

Cholerae

Exposure from poor hygiene

Eating raw or undercooked food, shellfish

Susceptibility to cholera may be increased by adeficiency or an absence of hydrochloric acid.


42/79

Signs & Symptoms ofCholera

Symptoms begin 1 to 3 days after infection and range frommild, uncomplicated diarrhea to severe, potentially fataldisease. Some infected people have no symptoms. The

infection is often mild or without symptoms, but sometimescan be severe. The infected person has several symptomswhich can be characterized by:

Abdominal cramps, Dehydration, Diarrhea, Dry mouth, Dryskin, Excessive thirst, Leg cramps, Low urine output, LowBlood Pressure, Nausea, Rapid heart rate, Sunken

eyes, Tiredness, Unusual sleepiness, Vomiting, Waterydiarrhea,

In the infected persons, rapid loss of body fluids leads todehydration and shock. Without treatment, death canoccur within hours.


43/79

Diagnosis of cholera

Cholera is diagnosed by taking the stool sample and to identifythe bacteria that can cause cholera. Cholera requiresimmediate treatment because of watery diarrhea, so the doctorsare likely to begin dehydration before a definitive diagnosis ismade.

A doctor confirms a diagnosis of cholera by recovering thebacteria from rectal swabs or from fresh stool samples.

A dark-field microscopic examination of fresh feces showingrapidly moving bacilli allows for a quick, tentative diagnosis.

Cholera can be confirmed only by the isolation of the causativeorganism from the diarrheic stools of infected individuals.

All food isolates must be tested for the production of choleraenterotoxin.


44/79

Preventions ofCholera Cholera is usually transmitted through contaminated water or

food. Outbreaks can occur in any part of the world where watersupply, sanitation, food safety, and hygiene are inadequate.

Drink only boiled water

chlorine or iodine treatment

Eat only thoroughly cooked food and are still hot

Avoid undercooked or raw fish or shellfish.

Make sure all vegetables are cooked properly

Avoid foods and beverages from street vendors

Check for proper sanitation and water purification systems

Give liquid bland foods, lemon, onions and mint to the patient

Vegetables and fruits must be washed with solution ofpotassium permanganate

New Vaccines for cholera are available and appear to provide a

somewhat better immunity and fewer side-effects than thepreviously available vaccine.

Health education aimed at behaviour change is thus animportant component of cholera prevention and control


45/79

Treatments ofCholera

Cholera is an easily treatable disease.

Water and electrolyte replacement are essentialtreatments for cholera, The prompt

administration of oral re-hydration salts toreplace lost fluids nearly always results in cure.

Use of antibiotics

Hands that touch cholera patients or theirclothing and bedding should be thoroughly

cleaned and sterilized. Use of highly hygienic, properly cooked foodand cleaned boiled water.

Rigid purification of water supply and properdisposal of human excreta.

If left untreated, cholera can kill quickly.


46/79

Heavy metals induced disease


47/79


48/79

Changes in the Incidence of Vector-borne

Diseases Attributable to Climate Change

A vector-borne disease is one in which the pathogenicmicroorganism is transmitted from an infected individualto another individual by an arthropod or other agent

The transmission depends upon the attributes andrequirements of at least three different living organisms:the pathologic agent, either a virus, protozoa, bacteria, or

worm; the vector, which are commonly arthropods suchas ticks or mosquitoes; and the human host.

Nearly half of the world's population is infected by vector-borne diseases, resulting in high morbidity and mortality.

The distribution of the incidence of vector-borne diseases

is grossly disproportionate, with the overwhelming impactin developing countries located in tropical and subtropicalareas.

Weather affects vector population dynamics and diseasetransmission, with temperature and humidity consideredkey variables. . :


49/79

To better understand the potential impact of changes in

the incidence of vector-borne diseases attributable to

climate change requires examination of the following

topics

Current Status of Vector-borne Diseasesaround the World

Environmental Parameters That Affect the

Incidence of Vector-borne Diseases Models That Predict Changes in the Incidence

of Vector-borne Diseases Attributable toClimate Change

Possible Direct and Indirect Effects of ClimateChange on Specific Vector-borne Diseases

Programs forSurveillance, Treatment, andControl of Vector-borne Diseases


50/79

INTRODUCTION

Malaria is a potentially life threatening parasitic disease. causedby parasites known as Plasmodium viviax (P.vivax),Plasmodium falciparum (P.falciparum), Plasmodiummalariae(P.malariae) and Plasmodiumovale (P.ovale)

It is transmitted by the infective bite ofAnopheles mosquito

Man develops disease after 10 to 14 days of being bitten by aninfective mosquito

There are two types of parasites of human malaria, Plasmodiumvivax, P. falciparum, which are commonly reported from India.

Inside the human host, the parasite undergoes a series ofchanges as part of its complex life cycle. (Plasmodium is aprotozoan parasite)

The parasite completes life cycle in liver cells (pre-erythrocyticschizogony) and red blood cells (erythrocytic schizogony

Infection with P.falciparum is the most deadly form of malaria.


51/79

HISTORICALPERSPECTIVE Malaria has been a major public health problem in India. Intermittent fever, with

high incidence during the rainy season, coinciding with agriculture, harvesting, wasfirst recognized by Romans and Greeks who associated it with swampy areas.

They postulated that intermittent fevers were due to the 'bad odour' coming fromthe marshy areas and thus gave the name 'malaria' ('mal'=bad + 'air') tointermittent fevers. In spite of the fact that today the causative organism is known,the name has stuck to this disease.

MAGNITUDE OF THE PROBLEM

Data for the year 2006 reveals the largest numbers of cases in the country werereported by Orissa, followed by Jharkhand, West Bengal, Assam, Chhattisgarh,Rajasthan, Gujarat & Uttar Pradesh and the largest numbers of deaths werereported by Assam followed by Orissa, West Bengal,Arunachal Pradesh,Meghalaya, Maharashtra, Mizoram, Gujarat & Karnataka.

1.79 million cases of malaria (including 0.84 million P.falciparum cases) and 1707deaths were reported from the country in 2006.


52/79

SYMPTOMS OF MALARIA

Typically, malaria produces fever, headache, vomiting and other flu-likesymptoms.

The parasite infects and destroys red blood cells resulting in easyfatigue-ability due to anemia, loss of consciousness.

Parasites are carried by blood to the brain (cerebral malaria) and toother vital organs.

Malaria in pregnancy poses a substantial risk to the mother, the fetusand the newborn infant. Pregnant women are less capable of copingwith and clearing malaria infections, adversely affecting the unbornfetus.

Prostration (inability to sit), altered consciousness lethargy or coma

Breathing difficulties

Severe anaemia

Generalized convulsions/fits

Inability to drink/vomiting

Dark and/or limited production of urine


53/79

LIFE CYCLE OF MALARIAPARASITE

IN MAN AND MOSQUITO


54/79

MALARIACONTROLSTRATEGIES

Early case Detection and Prompt Treatment (EDPT) EDPT is the main strategy of malaria control - radical treatment is necessary for all the cases of

malaria to prevent transmission of malaria. Chloroquine is the main anti-malaria drug for uncomplicated malaria. Alternative drugs for chloroquine resistant malaria are recommended as per the drug policy of

malaria.

VectorControl

Chemical Control

Use of Indoor Residual Spray (IRS) with insecticides recommended under the programnme Use of chemical larvicides like Abate in potable water Aerosol space spray during day time Malathion fogging during outbreaks

Biological Control

Use of larvivorous fish in ornamental tanks, fountains etc. Use of biocides. (iii) Personal Prophylatic Measures that individuals/communities can take up


55/79

Use of mosquito repellent creams, liquids, coils, mats etc. Screening of the houses with wire mesh Use of bednets treated with insecticide Wearing clothes that cover maximum surface area of the body 4.Community Participation

Sensitizing and involving the community for detection ofAnopheles breeding places and theirelimination

NGO schemes involving them in programme strategies Collaboration with CII/ASSOCHAM/FICCI 5. EnvironmentalManagement & Source Reduction Methods

Source reduction i.e. filling of the breeding places Proper covering of stored water Channelization of breeding source 6.Monitoring and Evaluation of the programme

Monthly Computerized Management Information System(CMIS) Field visits by state by State National Programme Officers Field visits by Malaria Research Centres and other ICMR Institutes Feedback to states on field observations for correction actions.


56/79

Epidemiology

Epidemiology is the study of factors affecting

the health and illness of populations, and

serves as the foundation and logic of

interventions made in the interest ofpublic

health and preventive medicine. It is considered

a cornerstone methodology of public health

research, and is highly regarded in evidence-

based medicine for identifying risk factors fordisease and determining


57/79

The work of communicable and non-communicable disease epidemiologists

ranges from outbreak investigation, to study design, data collection and

analysis including the development of statistical models to test hypotheses and

the 'writing-up' of results for submission to peer reviewed journals.

Epidemiologists may draw on a number of other scientific disciplines such as

biology in understanding disease processes and social science disciplines

including sociology and philosophy in order to better understand proximate and

distal risk factors.

Environmental epidemiology

Environmental Epidemiology is the branch of public health that deals with

environmental conditions and hazards that may pose a risk to human health.

Environmental Epidemiology identifies and quantifies exposures to

environmental contaminants; conducts risk assessments and risk

communication; provides medical evaluation and surveillance for adverse

health effects; and provides health-based guidance on levels of exposure to

such contaminants.


58/79

Epidemiological Approach

Population-based health management

encompasses the ability to:

assess the health states and health needs of atarget population

implement and evaluate interventions that aredesigned to improve the health of thatpopulation

Efficiently and effectively provide care formembers of that population in a way that isconsistent with the communitys cultural, policyand health resource values.


59/79

Modern population-based health management is complex(medical, political, technological, mathematical etc.)

provide efficient and effective health care and healthguidance to a population.

health risk factors, incidence, prevalence and mortalitystatistics (derived from epidemiological analysis)

Examples of organizations that use population-basedhealth management that leverage the work and results of

epidemiological practice include Canadian Strategy forCancer Control, Health Canada Tobacco ControlPrograms, Rick Hansen Foundation, Canadian TobaccoControl Research Initiative.

Each of these organizations use a population-basedhealth management framework called Life at Risk that

combines epidemiological quantitative analysis withdemographics, health agency operational research andeconomics to perform:


60/79


61/79

Dose-response relationship

The Dose-response relationship describes the change ineffect on an organism caused by differing levels ofexposure (ordoses) to a stressor(usually a chemical). This may apply toindividuals (eg: a small amount has no observable effect, alarge amount is fatal), or to populations (eg: how many peopleare affected at different levels of exposure).

Studying dose response, and developing dose response

models, is central to determining "safe" and "hazardous" levelsand dosages fordrugs, potential pollutants, and othersubstances that humans are exposed to. These conclusions areoften the basis for public policy

Dose-response curve Adose-response curve is a simple X-Y graph relating the

magnitude of a stressor (e.g. concentration of a pollutant,

amount of a drug, temperature, intensity of radiation) to theresponse of the receptor (e.g. organism under study). Theresponse is usually death (mortality), but other effects (orendpoints) can be studied.


62/79

The measured dose (usually in milligrams,micrograms, orgrams per kilogram of body-weight) is generally plotted on the X axis andthe response is plotted on the Y axis.Commonly, it is the logarithm of the dose that isplotted on the X axis, and in such cases thecurve is typically sigmoidal, with the steepestportion in the middle.

Studying dose response, and developing doseresponse models, is central to determining"safe" and "hazardous" levels and dosages fordrugs, potential pollutants, and othersubstances that humans are exposed to. Theseconclusions are often the basis for public policy


63/79

Dose-response curve

A The first point along the graph where a response above

zero is reached is usually referred to as a threshold-dose.For most beneficial or recreational drugs, the desiredeffects are found at doses slightly greater than thethreshold dose.

At higher doses still, undesired side effects appear andgrow stronger as the dose increases. The stronger a

particular substance is, the steeper this curve will be. Inquantitative situations, the Y-axis usually is designated bypercentages, which refer to the percentage of usersregistering a standard response (which is often death,when the 50% mark refers to LD50). Such a curve isreferred to as a quantal dose response curve,

destinguishing it from a graded dose response curve,where response is continuous.


64/79

The science of toxicology is based on the principle that there isa relationship between a toxic reaction (the response) egpoison received (the dose).

An important assumption in this relationship is that there isalmost always a dose below which no response occurs or canbe measured.

A second assumption is that once a maximum response isreached any further increases in the dose will not result in anyincreased effect.

One particular instance in which this dose-response relationshipdoes not hold true, is in regard to true allergic reactions. Allergicreactions are special kinds of changes in the immune system;

they are not really toxic responses. The difference between allergies and toxic reactions is that a

toxic effect is directly the result of the toxic chemical acting oncells.

Allergic responses are the result of a chemical stimulating thebody to release natural chemicals which are in turn directlyresponsible for the effects seen.

For all other types of toxicity, knowing the dose-responserelationship is a necessary part of understanding the cause andeffect relationship between chemical exposure and illness.

Keep in mind that the toxicity of a chemical is an inherentquality of the chemical and cannot be changed withoutchanging the chemical to another form. The toxic effects on anorganism are related to the amount of exposure.


65/79

MEASURES OF EXPOSURE

Exposure to poisons can be intentional or unintentional. Theeffects of exposure to poisons vary with the amount of

exposure, which is another way of saying "the dose. Usually when we think of dose, we think in terms of taking one

vitamin capsule a day or two aspirin every four hours, orsomething like that.

Contamination of food or water with chemicals can also providedoses of chemicals each time we eat or drink. Some commonlyused measures for expressing levels of contaminants are listed

in table These measures tell us how much of the chemical is in food,

water or air.

The amount we eat, drink, or breathe determines the actualdose we receive. Concentrations of chemicals in theenvironment are most commonly expressed as ppm and ppb.

Government tolerance limits for various poisons usually use

these abbreviations. Remember that these are extremely small quantities. For

example, if you put one teaspoon of salt in two gallons of waterthe resulting salt concentration would be approximately 1,000ppm and it would not even taste salty!


66/79


67/79

Regardless of how a chemical effect occursthroughbinding or chemical interactionthe concentration of thedrug at the site of action controls the effect.

However, response to concentration may be complex andis often nonlinear. The relationship between the chemicaldose, regardless of route used, and the drugconcentration at the cellular level is even more complex.

Dose-response data are typically graphed with the doseor dose function (eg, log10 dose) on the x-axis and the

measured effect (response) on the y-axis. Because a drug effect is a function of dose and time,

such a graph depicts the dose-response relationshipindependent of time.

Measured effects are frequently recorded as maxima attime of peak effect or under steady-state conditions (eg,during continuous IV infusion). Drug effects may bequantified at the level of molecule, cell, tissue, organ,organ system, or organism.


68/79

Individual Dose-Response Curve


69/79

Lethal Dose The lethal dose (or LD) test measures the amount of a

toxic substance that will, in a single dose, kill a certainpercentage of animals in a test group. "To avoidinterference with results," no painkillers are administered.Each year, about five million dogs, rabbits, rats,monkeys, and other animals die in lethal dose testsperformed

The most commonly-used lethality indicator is the LD50(or LD50), a dose at which 50% of subjects will die. LD

measurements are often used to describe the power ofvenoms in animals such as snakes.

Animal-based LD measurements are a commonly-usedtechnique in drug research, although many researchersare now shifting away from such methods.

LD figures depend not only on the species of animal, butalso on the mode of administration. For instance, a toxicsubstance inhaled or injected into the bloodstream mayrequire a much smaller dosage than if the samesubstance is swallowed.

LD values for humans are generally estimated byextrapolating results from testing on animals or on humancell cultures.


70/79

An externality occurs in economics when a decision causes

costs or benefits to individuals or groups other than the personmaking the decision.

In other words, the decision-maker does not bear all of the

costs or reap all of the gains from his or her action.

As a result, in a competitive market too much or too little of the

good will be consumed from the point of view of society..


71/79


72/79

An advantageous impact is called an externalbenefit orpositive externality, while a

detrimental impact is called an external cost or

negative externality.

Example: Effects of locating an oil refinery

adjacent to a residential neighborhood: air

pollution and associated health effects, noise

pollution, light pollution, increased traffic, risk of

industrial accident (all negative externalities)

and availability of high-paying jobs, increasedtax base for schools and other infrastructure

(positive effect).


73/79

Intangibles: A good, service, or effect of an

action that cannot be assigned monetary values

(text); cultural or personal values which cannot

be measured in monetary terms

Residuals: Waste products (i.e.. pollution)

created during the extraction, transportation,

refining, or manufacturing processes necessary

to deliver goods and service to the consumer.Example: Sulfur dioxide pollution created by

coal-fired electrical generating plant.


74/79

Incommensurable: Effects of a given

action that can, with some effort, be

assigned monetary value.Example: Cost of monitoring sulfur

dioxide pollution created by a coal-

fired electrical generating plant.


75/79


76/79

Direct Temperature Effects

Climate change may directly affect human health through increases inaverage temperature. Such increases may lead to more extreme heatwaves during the summer while producing less extreme cold spellsduring the winter. Increases in average temperatures are expected toresult in new record-high temperatures and warm nights (NRC, 2001).Particular segments of the population such as those with heartproblems, asthma, the elderly, the very young and the homeless can beespecially vulnerable to extreme heat.

The U.S. Environmental Protection Agency has produced the ExcessiveHeat Events Guidebook with the National Oceanic and AtmosphericAdministration (NOAA), the Centers for Disease Control andPrevention (CDC), and the Department of Homeland Security (DHS).Municipal officials in both the U.S. and Canada provided usefulinformation that can be used to help the public cope with excessive

heat.Designed to help community officials, emergency managers,meteorologists, and others plan for and respond to excessive heatevents, the guidebook highlights best practices that have beenemployed to save lives during excessive heat events in different urbanareas and provides a menu of options that officials can use to respondto these events in their communities.


77/79

Extreme Events

Extreme weather events can be destructive to

human health and well-being. The extent to

which climate change may affect the frequency

and severity of these events, such ashurricanes and extreme heat and floods, is

being investigated by the U.S. Climate Change

Science Program. An increase in the frequency

of extreme events may result in more event-related deaths, injuries, infectious diseases,

and stress-related disorders.


78/79

Climate-Sensitive Diseases

Climate change may increase the risk of some infectious diseases,particularly those diseases that appear in warm areas and are spread bymosquitoes and other insects. These "vector-borne" diseases includemalaria, dengue fever, yellow fever, and encephalitis. Also, algalblooms could occur more frequently as temperatures warm particularly in areas with polluted waters in which case diseases(such as cholera) that tend to accompany algal blooms could becomemore frequent.

Higher temperatures, in combination with favorable rainfall patterns,could prolong disease transmission seasons in some locations wherecertain diseases already exist. In other locations, climate change willdecrease transmission via reductions in rainfall or temperatures that aretoo high for transmission. For example, temperature and humidity

levels must be sufficient for certain disease-carrying vectors, such asticks that carry Lyme disease, to thrive. And climate change could pushtemperature and humidity levels either towards or away from optimumconditions for the survival rate of ticks.


79/79

AirQuality Climate change is expected to contribute to air quality problems.

Respiratory disorders may be exacerbated by warming-induced increases inthe frequency of smog (ground-level ozone) events and particulate airpollution.

Ground-level ozone can damage lung tissue, and is especially harmful forthose with asthma and other chronic lung diseases. Sunlight and hightemperatures, combined with other pollutants such as nitrogen oxides andvolatile organic compounds, can cause ground-level ozone to increase.

Climate change may increase the concentration of ground-level ozone, butthe magnitude of the effect is uncertain.

Another pollutant of concern is "particulate matter," also known as particlepollution or PM. Particulate matter is a complex mixture of extremely smallparticles and liquid droplets. When breathed in, these particles can reachthe deepest regions of the lungs. Exposure to particle pollution is linked to avariety of significant health problems. Particle pollution also is the main

cause of visibility impairment in the nations cities and national parks.Climate change may indirectly affect the concentration of PM pollution in theair by affecting natural or biogenic sources of PM such as wildfires anddust from dry soils.

environment change and health iii

Documents