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Global health
Reducing child mortality
Activity 3: Research Article
! Learn how to read researcharticles critically
! Title: Comparison of home-based therapy with ready-to-use therapeutic food with standard therapy in thetreatment of malnourished Malawianchildren: a controlled, clinical effectiveness trial .! American Journal of Clinical Nutrition,
2005
! Posted on my website as “A ctivity 3article 2005”
! Activity 3: read the article and answer the questions
“Big 4” infectious diseases thatkill children <5 yrs old worldwide
! Diarrhea! Kills 2 million infants and children each
year, usually from dehydration
! Respiratory infections! Pneumonia kills ~2 million children each
year
! Malaria
! AIDS
MDG 4:Reduce child mortality
! In 1990 12.6 million childrendied from preventablecauses
! This number has been cut to9 million
! Interventions:
! Vaccination campaigns(measles, etc)
! Expanding basic healthservices
Status report: MDG 4
! GOAL 4: Reduce child mortality
! Good Average Poor
!
Drop in the number of children dying of preventable causes
! BUT child mortality has increased in sub-Saharan Africa
! AIDS and malaria
1. Good nutrition
2. Good hygiene
3. Immunizations
The 3 most important thingsto protect children’s health:
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What happens when a childdoesn’t get enough food?
! When the mom is malnourished, her fetus doesn’tgrow normally
! Low birth weight
! If the child is chronically underfed, s/he doesn’t grownormally
! Stunting
! A transient lack of food leads to extreme thinness butrelatively normal height for age
! Wasting
! Micronutrient deficiencies
! Iron, iodine, vitamin A
Maternal malnutritionincreases infant mortality
! Every year, >20 million low-birth weight babies are bornin developing countries
Increased risk dying ininfancy
! Those who survive oftensuffer lifelong physical andmental disabilities
I n f a n t m o r t a l i t y
( d e a t h s / 1 0 0 0 b i r t h s )
I n d u
s t r i a
l i z e d
D e v
e l o p i n
g
Undernourished children
! Stunted growth, wasting
! Poor motor development
! Impaired mentaldevelopment
! Reduced learningcapacity
! Behavioral problems
! Decreased resistance toinfection
! Diarrhea and respiratory
infections (pneumonia)
Vicious cycle of malnutritionand illness
Poor nutrition Infection
! Weakened immunesystem
! Increasedsusceptibility toinfection
! Loss of appetite
! Vomiting
! Diarrhea
! Weight loss
Diarrhea and dehydration
! Diarrhea is common in developingcountries
! 60-70% of child deaths due to diarrhea
! Often caused by contact with food/water contaminated with feces
! Leads to dehydration
! Death can occur within 24 hr
What causes diarrhea?
! Bacteria
! Found in contaminated water
! cause typhoid, cholera, etc.
! Found in contaminated milk and dairy
products, salads and poultry (Shigellabacteria)
! Ameba - cause amebic dysentery
! Found in food or water contaminated byfeces
! Rotavirus family of viruses
! Commonly infect children
An ameba
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Cholera
! Caused by a toxin secreted into theintestine by the bacterium Vibrio
cholerae
! Bacteria is transmitted bycontaminated water or food
! Sx: Massive watery diarrhea
! Loaded with bacteria
! Spreads the infection
! One of the most rapidly fatal illnessesknown
! Dehydration
! Rx: oral rehydration therapy Cholera hospital in Dhaka
Simple Rx:Oral Rehydration Therapy
! One of greatest public healthbreakthroughs of 20th century
! ORT prevents 1 million deaths per year
! Replace the fluid and salt lost throughdiarrhea
! Rehydration solution contains water,salt and sugar
! Add sugar - enhances transport of salts across intestinal wall
! Caveat: best to use clean (boiled) water so don’t re-infect the child
Preventing Diarrhea
! Clean water
! Good hygiene
! Wash your hands! After pooping, diaper changes, before preparing meals andfeeding kids
Waterborne diseases
! Safe drinking water andsanitation are key to publichealth, yet! 1/3 of world’s population lacks
modern sanitation
! 1/6 of population lacks access tosafe drinking water
! Contaminated water ! Leading cause of disease and
death
! Single largest killer of infants
! Principal cause of illness in adults
Preventing waterbornediseases
! Build basic infrastructure: Water treatment and sanitation systems
! Treat sewage before it enters the
waterways
! Water purification
! Sterilize all water used for drinking,washing, or cooking by boiling or chlorination
Not a small problem …
! Over 2 billion people (1/3 of the world’spopulation) still lack modern sanitationand hygiene needed to protect their
environment from human fecalcontamination
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Complex challenges for developing nations
! Contaminated water
! Uncollected garbage
! Untreated sewage
! Other disease vectors
! rodents (plague), mosquitoes (malaria, denguefever), flies, cockroaches, …
! Parasites: tapeworms, hookworms, etc.
! Contaminated food due to no refrigeration
Respiratory infections/pneumonia
! Indoor air pollution is a major contributing factor
! Half the world’s people use dung, wood,or coal for cooking and heating
! Poor ventilation of smoke (no chimney)
! Pneumonia
! an infectious disease caused by varietyof pathogens: bacteria, viruses,parasites or fungi
! Causes severe inflammation of lungs,difficulty in breathing
Two billion people use openfires as their primarycooking method.
Infectious disease: Malaria
! Malaria kills more than 3000children under the age of 5 eachyear
! The majority of the cases occur in Africa, where poverty is thebiggest problem facing thisepidemic
! Prevention! mosquito nets and mosquito repellant
! mosquito control (pesticides)
! No vaccine is available–yet
Infectious disease: Measles
! The world’s most contagious disease! Caused by a virus
! Young, malnourished children espvulnerable
! In developing nations, a child has a5-15% chance of dying from measles
! Many survivors suffer seriouscomplications! Blindness, loss of hearing, nerve damage
Preventing Measles
! Vaccination! Vaccine costs 26 cents per dose – but has yet to
reach many of the world’s poorest countries.
! Vaccine has not reached everyone in Africa, South Asia
! Vaccination: if >90% coverage, the populationwill achieve “herd immunity”
! Immunization levels high enough so that minoritynot immunized will still be protected.
Importance of immunizations
! Measles vaccination program in Latin American and Caribbean
! Strategy of “catch up, keep up and follow up”! “Catch up” campaign to achieve 90% vaccination
coverage! Maintenance to “keep up” to 80% coverage
! Regular “follow up” campaigns every 3-4 yrs
! Dramatic drop in measles cases! 250,000 in 1990
! 537 in 2001
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What is a vaccine?
! Purpose: get the immune systemready to fight without exposing
anyone to active germs
! What’s in that syringe?
! Dead or weakened viruses
! Inactivated toxins
! Part of a virus
! Boost the immune system sothat it produces antibodies to thepathogen
Strategies for improvingchild survival
Interventions that improvehealth and nutrition
! Promoting breast feeding
! Educating moms about feeding at weaning
! Micronutrient supplements
! Vitamin A and zinc supplements for kids
! Could reduce deaths by about 10%
! Calcium, iron & folate supplements during pregnancy
! prevent 1/4 of all maternal deaths
! Reduce the burden of disease
! Promote hand washing
! Reduce malaria (bed nets)
Breastfeeding–Global recommendations
! Educate new moms aboutthe benefits of breast milk
! Encourage mothers tobreastfeed exclusively for first 6 months
! Continue breastfeedingwith complementary fooduntil the child is at least 2
Breast feeding - advantages
! Optimal nutrients for healthy growth
! Contains antibodies thatprotect against disease
! Sanitary
! Always ready
! Inexpensive
! May delay subsequentpregnancies
Breastfeeding Setbacks
! The number of infants exclusively breastfedto 4 months has dropped to ~50%
! Aggressive promotion of infant formula to
new mothers! More women working outside the home
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What if the mother is HIV-positive?
! A complicated decision
! The HIV virus is transmitted through breast milk
! Need to educate HIV-positive moms
! Shortened duration of breast feeding is an option – esp. in areas that lack clean water
! Study: Infants of HIV+ moms breast fed for the first 3-mo have same risk of contacting HIV as infants fedformula
Challenges–
! Implementing successfulprograms
! Promoting exclusive breast feedingfor the 1st 6 months
! Micronutrient supplementation
! Reaching those in need
! Women
! Young children (esp under 2 yrs)
! The poor
Deadliest diseases for adults
! HIV/AIDS
! TB
! Malaria
Top 6 “killer” infectiousdiseases worldwide
Disease Estimated # of deaths
1. Respiratory infections 3.9 mil lion
2. HIV/AIDS 2.9 million
3. Diarrhea 2.0 million
4. Tuberculosis 1.6 million
5. Malaria 1.1 million
6. Measles 0.7 million
WHO 2002
Tuberculosis (TB)
! Caused by the bacterium Mtb
! A contagious, airborne disease! Transmitted thru coughing,
sneezing, talking
! A person with active TB infects 10-20 others, often family members andcaretakers
! TB usually attacks the lungs anddestroys lung tissue! Sx: severe cough, chest pain,
coughing up blood
Infection with Mtb
! Latent! The immune system sequesters the bacteria and
prevents them from multiplying
! May persist for years without making its host ill
! 90% of people infected with Mtb never developactive TB disease
! Active TB! Develops in people with weak immune systems
! Bacteria multiply rapidly and attack the organs,esp the lungs
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TB
! 98% of new infections occur in the developingworld
! Rising number of people in industrialized
nations are contracting TB
! their immune systems are compromised by AIDS,immunosuppressive drugs, substance abuse
! Global transmission by jet travel
! Leading cause of death among people withHIV/AIDS
Treating TB
! Difficult, expensive,requires long courses of multiple antibiotics
! Drug-sensitive TB isusually cured with acombination of first-linedrugs taken for 6 to 9months.
! These drugs weredeveloped more than40 years ago.
Antibiotic resistance is agrowing problem
! Many patients stop taking meds when they begin to feel well
! Inconsistent use of antibiotics give the bacteria time to evolveinto a drug-resistant form
Multidrug resistant TB (MDR-TB)
! MDR TB occurs when the Mtbstrain is resistant to the mostpowerful first-line drugs.
! To cure MDR TB, a combination of second-line drugs is used
! These drugs have more sideeffects, the treatment lasts muchlonger, and the cost may be up to100 times more than first-linetherapy
Challenges in TB treatment
! 20% of TB cases are resistant to standard treatments! Multidrug-resistant TB (MDR-TB)
! Extensively drug-resistant TB (XDR-TB)
! Desperate need for better drugs and vaccines!
Drugs that are easier to administer and cheaper ! Vaccine to prevent TB infection in the 1st place
! Mtb genome was sequenced in 1998! new insights into how the bacterium infects humans
! Gates Foundation: $$ to develop new drugs and vaccines
Malaria
! Caused by a tiny parasiticprotozoa, Plasmodium
! Vector: female Anopheles
mosquito! Parasites transmitted from
one human to another by thebite of this mosquito
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Malaria–populations that face the greatest risk
! Endemic to tropicalareas in Africa, Asiaand South America
! Each year 250-500million people areinfected
! Vast majority of victims are childrenunder 5
World Malaria report 2010
! Deaths from malaria dropped 21% over past9 yrs
! Vast majority of victims: children under 5
! strategies to fight malaria! Bed nets in sub-Saharan Africa
! Spray houses with insecticide
! Rapid diagnostic tests
! Combination therapy
Malaria–the parasite has a complex life cycle
! Starts in the salivary glands of mosquitoes
! Moves to the humanbloodstream
! Migrates to the liver where itreproduces, forming thousandsof merozoites.
! These invade RBCs andmultiply, causing the cells torupture and infect more RBCs.
! Finally moves back into thebody of a new mosquito
Malaria symptoms
! Sx: severe fever and flu-likeillness, chills, anemia
! Sx caused by! the massive release of
merozoites into thebloodstream
! Anemia results from thedestruction of RBCs
! Jaundice (yellow-colored skinand eyes) caused by largeamounts of hemoglobinreleased into the blood after RBCs rupture
RBC bursting after
malaria infection
Malaria–transmission
! The parasite enters thehuman body in one of three ways
!
The bite of infected Anopheles mosquitoes
! Congenitally (from amother to her fetus)
! Transfusions withinfected blood
Malaria - interventions
! Insecticides to kill mosquitoes! DDT used indoors to kill mosquitoes w/o harming environment
! Mosquito nets for beds ( Anopheles is a night feeder),insect repellants
! Anti-malarial drugs! must be taken continuously to reduce infection
! Too expensive for people living in endemic areas
! Plasmodium parasite is becoming resistant to older medications
! No vaccine for malaria - yet
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Malaria vaccine 3:22http://www.pbs.org/newshour/video/module_byid.html?s=news01pb88
Why isn’t there a vaccine for malaria?
! Developing a malaria vaccine is one of the mostimportant research projects in public health, but ...
! The malaria parasite is a complex organism with acomplicated life cycle.! It is constantly changing – so developing a vaccine is
difficult.
! Scientists don’t understand the immune responsesthat protect humans against malaria.
Promising new vaccinestrategies
! A stronger traditional vaccine
! Chemicals added to boost the immune response
! In late stage clinical trials, but only 50% e ffective
! A vaccine from weakened parasites
! Irradiate parasites in the mosquito’s gut, then inject pieces of weakened parasite into humans to trigger immune response
! Develop a vaccine for mosquitoes
! To break the cycle of transmission
Socio-economic effects
! Malaria is associated with poverty! but is also a cause of poverty
! Malaria hinders economic development! impact includes costs of health care
! working days lost due to sickness
! days lost in education
! decreased productivity
! PBS - Malaria in Tanzania 3:55! http://www.pbs.org/newshour/video/search_results.html?q=malaria&submit=Search
Genetic disorders:
Sickle-cell Anemia
! A recessive genetic disorder
! Caused by a mutated gene thatproduces a defective version of hemoglobin
! The hemoglobin sticks together and produces a stiff red bloodcell with a sickle-shape
! Sickled RBCs are destroyedrapidly, leading to anemia
Sickle cell trait and malaria
! People (and particularlychildren) infected withmalaria parasite are more
likely to survive the acuteillness if they have sickle celltrait.
! The sickling of the cells haltsinfestation of the malariaplasmodium
Neglected Tropical Diseases
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Neglected Tropical Diseases
! About 1 billion peopleare affected by one or more neglected tropicaldiseases (NTDs)
! Diseases of poverty! These diseases are
named "neglected"because they persist inthe poorest and the mostmarginalized populations.
Neglected Tropical Diseases
! Most are parasitic or bacterialinfections! Parasitic worms that live in the intestine
! Rob children of nutrients, stunting their growth
! Don’t often kill, but they debilitate bycausing severe anemia,malnutrition, delays in cognitivedevelopment
! They help perpetuate poverty! Children have trouble learning in school
! Adults workers are less productive
Filtering water
NTDs 3:21http://www.pbs.org/newshour/video/module_byid.html?s=news01pb88
Neglected Tropical Diseases
! The 3 most common NTDsare caused by parasiticworms that live in theintestines
! Large common roundworm, Ascaris
! Afflicts 800 million people
! Whipworm – 600 million
! Hookworms – 600 million
Ascaris roundworm
Treating NTDs
! The good news: NTDs canbe treated simply andcheaply
! However WHO estimates thattreatment programs reachless than 10% of peoplesuffering from NTDs
! Strategies: fold in with other interventions! Bed nets
! Immunizations
!
Nutritional supplements such asvitamin A