Human Health and DiseaseWhat is health? ‘The state of complete physical, mental and social well-being’ To sustain a healthy lifestyle person needs:•A balanced and varied diet∀• Take exercise∀• Proper shelter∀• Enough sleep Good hygiene will reduce the likelihood of infection
What is disease?Disease is a disorder or malfunction of the mind or body, which leads to a departure from good health.Can be a disorder of a specific tissue or organ due to asingle cause. E.g. malaria.May have many causes.Often referred to as multifactorial. E.g. heart disease.Disease diagnosed by a doctor analyzingthe symptoms (physical and mental signs).
Acute diseaseSudden and rapid onset Symptoms disappear quickly E.g. influenza Chronic disease Long term Symptoms lasting months or years E.g. Tuberculosis
Physical diseaseResults from permanent or temporary damage to the bodyIt could be acute or chronicExamples: AcuteBronchitis Cold Sores CommonColdInfluenzaExamples: ChronicAsthmaAutoimmune diseaseDiabetesEczema
Infectious diseases Organisms that invade the body and cause disease inside are called pathogensBacteria and Viruses are the bestknow pathogens. They grow &reproduce within the body oftheir host. Fungi, protists and parasites can also cause disease. Sometimes worms.Diseases are said to beinfectious or communicable ifpathogens can be passed fromone person to another.
• Some examples to follow• For a list of more with details see pages 250-251 in your book 7
Influenza (flu)Influenza is a virus which causes a severe form of respiratory tract infection with generalized bodilysymptoms. It spreads around the world in epidemics and is responsible for much ill health as well asmany deaths.SymptomsIf you start to develop cold symptoms but starting more rapidly and rather more violently, with higherfever and severe aches and pains, often in the back and muscles, then you may well be developinginfluenza. This may be associated with severe headache, cough, and, as a result of the fever,intermittent sweating and shivering. Sometimes there is a gastrointestinal element, with vomitingand/or diarrhea.Many people think they have had "flu" when all that they have suffered is a bad cold. When you haveinfluenza you will know the difference. Most people will find it impossible to leave their bed and feelterrible.The worst symptoms usually last for three to five days, and then should begin to improve. It iscommon to need two to three weeks off work as there is considerable debility left after the feverishillness is over. Do not be surprised to be quite depressed, this is a natural after-effect of the condition.Influenza makes everyone feel terrible, but most people recover. It does however have a small, butsignificant mortality, especially in the very young, the very old, and those with poor immunity.CausesInfluenza is caused by a virus which attacks our body cells resulting in various manifestationsdepending on the strain of the virus.New mutations of the virus arise all the time and unfortunately immunity against one strain (which isconferred by exposure or immunization) does not protect against other strains. In the era of rapid airtransport the world wide spread of a new type of influenza can be extremely fast.
SalmonellaSalmonellosis is an infection with a bacteria called Salmonella. Most persons infected with Salmonelladevelop diarrhea, fever, and abdominal cramps 12 to 72 hours after infection. The illness usually lasts 4 to7 days, and most persons recover without treatment. However, in some persons the diarrhea may be sosevere that the patient needs to be hospitalized. In these patients, the Salmonella infection may spread fromthe intestines to the blood stream, and then to other body sites and can cause death unless the person istreated promptly with antibiotics. The elderly, infants, and those with impaired immune systems are morelikely to have a severe illness
Cholera is an acute, diarrheal illness caused by infection of theintestine with the bacterium Vibrio cholerae. The infection is oftenmild or without symptoms, but sometimes it can be severe.Approximately one in 20 infected persons has severe diseasecharacterized by profuse watery diarrhea, vomiting, and leg cramps.In these persons, rapid loss of body fluids leads to dehydration andshock. Without treatment, death can occur within hours.Zimbabwes cholera epidemic hits 10,000Zimbabwes cholera epidemic hits 10,000 10
Typhoid fever is contracted when people eat food or drink water that has been infected withSalmonella typhi. It is recognized by the sudden onset of sustained fever, severe headache,nausea and severe loss of appetite. It is sometimes accompanied by hoarse cough andconstipation or diarrhea. Case-fatality rates of 10% can be reduced to less than 1% withappropriate antibiotic therapy. Paratyphoid fever shows similar symptoms, but tends to be milderand the case-fatality rate is much lower. 11
• Clinical Tetanus sometimes known as “lock jaw”-Spores deposited in tissue- wound, burn, ulcer, compound fracture, operative wounds, druginjection- tetanus neonatorum: infection of umbilical stump- necrotic tissue (poor blood supply, anoxia)- mixed infections, foreign bodies also contribute-Toxins affect the central nervous system by causing continualimpulses to be sent to the muscles. They contract and becomeremain rigid.-If not treated the person often dies a painful death as more andmore of the muscles are affected.
MalariaMalaria infects an estimated 300 million people, and is spread by mosquitoes,transfusions, and shared hypodermic needles. Control of mosquito populations has led todeclines in malaria in many areas. Infected individuals can be treayted with a variety ofmedicines. However, some of the sporozoans that cause malaria heve developedimmunity to some of the more commonly employed medicines.
Global Statistics • 40% of the worlds population is at risk • 300-500 million new cases/year • 1.5-2.7 million deaths/year• Malaria is endemic to over 100 countries and territories • More than 90% of all cases are in sub-Saharan Africa
• Tree or Root Man, What cause it?• Dede Koswara, Tree Man 15
Droplet Infection• Transmitted by pathogens suspended in water droplets that humans cough or sneeze into the air. • Airborne infections generally affect the respiratory tract, though some of them affect other parts of the body as well.• The spread of these diseases is curtailed by practicing sanitary precautions. 17
Contact Infections• Some diseases are spread by direct contact with a sore or lesion on the skin or mucous membrane of an infected person. • Scarlet fever, colds, influenza, and measles can be transmitted by touch. 18 18
Contamination Infection • Pathogens enter the body by way of contaminated food or water often afflict the digestive system. • The intestinal wastes of a person who has this disease are highly contagious.19 19
Wound Infections• Some pathogens enter the body through wounds.• Even small cuts can be serious if they are not properly treated.• Enters through the bloodstream and spreads to other 20 parts of the body.
Vector-carried Infection• Insects or other arthropods that carry pathogens to other host organisms are are vectors.• Either mechanically, as with food contamination by pathogens carried on the bodies of flies or roaches or...• By the bites of such organisms as mosquitoes, flies, or ticks, which inject the pathogen into the bloodstream of the host. 21
Immune Carriers• Diseases are also spread by people, and occasionally animals, who spread pathogens to others without suffering from the disease themselves• They might have had the disease before and have developed an immunity to it. 22 22