are caused by microorganisms or other agents, such as bacteria, fungi, or viruses. enter the body of an organism, proliferate, and cause infection. can be spread, directly or indirectly, from one person to another.
Causes of InfectiousDiseases:Bacteria: These organisms areresponsible for illnesses such asstrep throat, urinary tractinfections, and tuberculosis.Viruses: Smaller thanbacteria, viruses cause a multitudeof diseases ranging from thecommon cold to AIDS.Fungi. Many skin diseases, suchas ringworm and athletes foot, arecaused by fungi. Other types offungi can infect your lungs ornervous system.Parasites. Malaria is caused by atiny parasite that is transmitted bya mosquito bite. Other parasitesmay be transmitted to humansfrom animal feces.
Table 1. Top five pathogens contributing to domestically acquired foodborne illnesses Pathogen Estimated number of illnesses Norovirus 5,461,731 Salmonella, nontyphoidal 1,027,561 Clostridium perfringens 965,958 Campylobacter spp. 845,024 Staphylococcus aureus 241,148
Contaminated food and water. Airborne transmission Direct contact Vectors and Fomites Blood
Infectious diseases have arange of signs andsymptoms.General signs andsymptoms of infectiousdiseases include:
Various accomplished scientists have made strides towardunderstanding and preventing the spread of infectious diseases;and have developed treatments including antibiotics andvaccines.
Known as “The Savior of Mothers”, Semmelweiss first discovered theimportance of physician’s hand-washing prior before child-birthing, toprevent contamination from one patient to another.
Pasteur’s pasteurization technique was initially used to reduce the number ofpathogens in foods such as wine, beer, and milk. He proved that bacteria camefrom the environment; instead of the commonly held belief - spontaneousgeneration. He extended the Germ Theory to explain the causes of manydiseases - including anthrax, cholera, tuberculosis, and smallpox.Pasteurization led to the advancement of vaccinations.
Joseph Lister covered compound fracture wounds with lint soaked in carbolicacid. Following implementing this practice, patient death by gangrene droppeddramatically. He later implemented pre-operative hand-washing and instrumentsterilization. Lister developed a phenol (antiseptic) spray; which he administered intothe air surrounding the operating area, to reduce infection from environmentalpathogens. The post-operative death rate of his patients fell from nearly 46% to 15%.
In 1928, accidentally discovered a breakthroughin medicine.
While working with the influenza virus, Flemingobserved that mold had accidently developed on abacterial culture plate and had formed a bacteria-freecircle around a bacterial colony. He discovered that amold culture prevented the growth of Staphylococci. Theactive substance in the mold has now come to be knownas…
… which has come to be recognized as one of themost commonly prescribed antibiotics the world has known to date!!!
Tests & DiagnosisBlood tests.Urine and stool tests.Throat swabs.CT ScanBiopsySpinal tap (lumbar puncture).
Treatment & DrugsAntiviralsDrugs have been developed to treatsome, but not all, viruses. Examplesinclude the viruses that cause:• AIDS• Herpes• Hepatitis B• Hepatitis C• InfluenzaAntibiotics• Penicillin (Permapen)• Amoxicillin (Moxatag)• Ciprofloxacin (Cipro)• Azithromycin (Zithromax)• Doxycycline (Doryx, Oracea)AntifungalsAnti-parasitic drugs
World Health Organization, The Global Burden of Disease 2004 Update, Geneva: 2009Global distribution ofdeaths among childrenunder age 5, by cause,2010