Microbiology Lecture 20 Chapter 20 Preventing Disease p.507-526

Snow on cholera. A classic of epidemiology. Companies supplying water: Southwark and Vauxhall (Thames in London source)315 deaths per 10,000 households. Lambeth (Thames source well upstream from London) 59 deaths/ 10,000 households.

Endemic: Constantly present

Epidemic: Unusually high numbers in a local area

Outbreak: Large number of cases in short time period

Fomite: Inanimate object capable of transmitting pathogen to a host

Common-source epidemic: Large number infected from a single contaminated source. Sharp rise and fall

Host-to-host epidemic: person-to-person contact distributes. Slow rise and fall in numbers

Vector: Living agent that transfers pathogen

Morbidity: incidence in a population

Mortality: incidence of death in a population

Chronic: long-term

Acute: short-term (dramatic onset and recovery)

Incidence: rate of new acquisitions

Prevalence: rates of individuals that have disease

More deadly, transmissible = notify first (see p.510, table 20.2)

South American cholera epidemic in 1992 = "bad news". Sometimes recurrent in new areas.

"Physicians... must notify..." Laws designed to protect reporter, so, no retaliation. Some = finger their worst enemy. One case= poetic justice; accuser died from AIDS

Descriptive epidemiology can yield surprises. Age-adjusted shigellosis (sig. for young)

T.B. scourge on coasts, prison populations.

Many significant causes of death in first world = human activities (smoking, suicide, HIV, etc.) How about terrorism? Smallpox eradicated worldwide? Millard Henry renewed vaccinations

Nosocomial: Pseudomonas aeruginosa extremely adaptable (grows in disinfectants, aerators!)

Urinary tract, wound infection, pneumonias most significant.

Diarrheal diseases kill millions of children per year (GOBI strategy saved millions in overpopulated areas). Interfere with transmission. Clean water, clean food, wash hands, control insects, control yourself (STDs), etc. Immunization opposed by Charles Darwin (let weak die!)

Attenuated: weakened. Killed vaccines safer, not as vigorous a response. Acellulars = most safe.

DNA vaccines to provoke constant antigen production. Toxoids; immunogenic, inactive toxins.

Active, passive immunization. Many pathogens no vaccines made.

Classic of epidemiology: rabbits in Australia. Myxovirus from Brazilian rabbits into Australian rabbits. Third try: successsful. Killed 99.9....% of Australian rabbits. In time, rabbit resistance up, viral virulence down. Coevolution. Repeated by mistake years later with untested pathogen!

UNICEF's GOBI -- FFF Programs http://www.rehydrate.org/facts/gobi_fff.htm

For a few years, the 'State of the World 's Children' report had drawn worldwide attention to the fact that just four relatively simple and inexpensive methods could now enable parents themselves to have the rate of child deaths and save the lives of up to 20,000 children each day. In brief, those methods are:
GROWTH MONITORING
- which could help mothers to prevent most child malnutrition before it begins. With the help of a U.S. 10-cent growth chart, and basic advice on weaning, most mothers could maintain their child's healthy growth - even within their limited resources. More than 200 different growth charts are coming into over 80 countries.
ORAL REHYDRATION
- which could save most of the more than 4 million young children who now die each year from diarrhoeal dehydration. (*A more detailed report on this appears on Pg ORS - Salts of Life). One out of every 20 children born into the developing world dies due to dehydration brought on by ordinary diarrhoea, before reaching the age of 5. It is the biggest single cause of child deaths in developing countries. Previously, the only effective treatment for dehydration was the intravenous feeding of a saline solution - a cure beyond the physical and financial reach of most of those who need it. Now a child can be rehydrated by drinking a solution of salts, sugar and water administered by the mother in the child's own home. Most of these children could be saved by this simple Oral Rehydration Therapy (ORT). It is one of the simplest but most important breakthroughs in the history of science.
BREAST-FEEDING
- which can ensure that infants have the best possible food and a considerable degree of immunity from common infections during the first six month of life. For infants, breast-milk is more nutritious, more hygienic, and provides a degree of immunity from infection. For the mother, breast-feeding is economical - but it also makes heavy demands on hew energy, time, and freedom of movement. A full five dollars course of
IMMUNIZATION
- which can protect a child against measles, diphtheria, whooping cough, tetanus, tuberculosis, and polio. At present, these diseases kill as estimated 5 million young children a year, leave 5 million more disabled, and are a major cause of child malnutrition.
In addition, recent research in the developing world has highlighted three kinds of support for women. These changes are sometimes known as the three F's:
FEMALE EDUCATION:
even within low-income communities, a child born to a mother with no education has been shown to be twice as likely to die in infancy as a child born to a mother with even four years of schooling.
FAMILY SPACING:infant and child deaths have been found to be , on average, twice as high when the interval between births is less than two years.
FOOD SUPPLEMENTS:
a handful of extra food each day for at-risk pregnant women has been shown to reduce the risk of low birth-weight - a risk which carries with it a two or three times greater likelihood of death in infancy.
THROUGH UNICEF'S GOBI-FFF PROGRAM
We are now taking about a particular opportunity to save the lives of approximately 7 million young children a year, and to protect the normal development of many millions more, at a cost which certainly does not exceed a fraction of 1% of the world's gross international product. If the will to accept that challenge is missing , then perhaps it will never be there. For in all realism, it is unlikely opportunity to do so much for so many, and for so little. Now is the time to act, now is the time to create. Now is the time for us to live in a way that will give life to others. Without you, Hunger persists. With you, Humankind's worst enemy can be eliminate, forever.