Dangerous Friends Friendly Enemies An Ancient Epidemic In May 1993 a flu like illness emerged in the Four Corners region of the SW United States Six young healthy people died They were feverish and their lungs rapidly filled with fluid before their death When microbes cross borders Local physicians realized they were seeing something new The disease acted quickly leaving its victims gasping for breath sending them into cardiac arrest within hours The disease killed about half of those 1993 victims The number of cases climbed a mother of two a man repairing his house and a teenager Panic spread first among the people of the Navajo nation and spread to the surrounding communities Looking for a cause Center for Disease Control Investigators dispatched from Atlanta to New Mexico set up a disease investigation analyzing blood samples from the victims and questioning close family and friends Hantavirus Sin nombre Virus By June 3 1993 it was confirmed that the disease had been caused by the Hantavirus which multiplies in a white footed rodent Apidemus agrarius aka the deer mouse The virus is harmless to the mouse For humans inhaling the virus via mouse pellets the virus was lethal Stopping the Source After the cause of the disease was discovered rodent control measures quickly reduced the number of cases in the following two years 1994 95 Researchers realized that the rodent population had increased due to the greater availability of food grain from a bumper crop of wild grasses after the unusually wet winter and spring of 1993 Human microbial ecology microbiomes The human body is comprised of 10 trillion cells The human body has 100 trillion bacterial cells on and in it There are 5 35 000 species in the human intestine 300 500 species in the mouth 1200 species on the skin There are 100 bacteria species pathogenic to humans Normal Flora Numbers of Microbial cells commonly found in or on tissues of healthy individuals 10 1 trillion bacteria on skin 10 100 billion in mouth 10 100 trillion in intestinal tract 6 5x10 people on Earth Distribution of Bacteria found on or within a healthy human Eyes rarely colonized due to lysozyme in tears Stomach highest number present immediately after a meal Undetectable numbers between meals Urogenital tract Number varies between people due to age and sexual development Urine previously thought to be sterile new studies show low numbers of microbes Blood normally free of bacteria sterile However some bacteria do slip through the intestinal tract barrier Bacteria can be recovered from your blood after you brush your teeth Skin First Barrier of Defense The surface of your body is not uniform and provides different environmental conditions for bacteria to grow 100 million skin cells are shed daily Think of skin as comprising of different regions each a unique ecosystem with abundant flora bacteria and some fungi Examples Forearm cool dry Armpit moist tropical heat What Microbes Live on Skin Staphylococcus epidermidids MAJOR Staphylococcus aureus minor othersMicrococcus luteus Corynebacterium ssp Classified into 4 groups 1 Lipophilic or nonlipophilic skin lipids and body oils 2 Anaerobic between your toes 3 Porphyrin producing makes a pigment 4 Kerationlytic enzyme producing lives in your armpits Various fungi Aspergillus Penicillium Cladosporium Mucor and many others usually associated with the scalp Normal flora can cause disease Normal flora can cause disease when introduced into internal areas of the body Other normal flora can become serious pathogens in their normal niche if conditions allow them to proliferate to a greater than normal extent The result is opportunistic infection Tatts Piercings and Infections Getting a tattoo may not seem dangerous but many tattoo recipients are now getting more than they anticipated Fine art tattooing has become a common practice among teenagers and young adults Sociological studies of tattoo recipients have shown that few recipients compare tattoo parlors or watch a tattooing procedure before getting one and few consider tattooing a future health risk Outbreaks of hepatitis have been identified in customers visiting certain commercial tattoo parlors on the same day Human skin is rich in sequestered microbial nutrients Most nutrients are contained within cells They are not available to invading microbial cells unless the microbe has the ability to lyse host cells to release the nutrients Microbes can gain access to the human body via piercing and tattooing Tattoo artwork and piercings have a price Allergic reactions Tattoo dyes particularly red dye can cause allergic skin reactions resulting in an itchy rash at the tattoo site This may occur even years after you get the tattoo Some piercing jewelry is made of nickel or brass which can cause allergic reactions Blood borne diseases If tattoo or piercing equipment or tattoo dyes are contaminated with infected blood a number of serious blood borne diseases can be transmitted Hepatitis B C and HIV syphilis tetanus and tuberculosis have been transmitted by tattoo Tattoo risk is serious enough the American Red Cross requires you to wait a year after getting a tattoo before donating blood Oral complications Jewelry worn in tongue piercings can chip and crack your teeth and cause gum damage Regret At some point you may decide you don t want your tattoo anymore it no longer fits your image or if it affects your career choices Tattoo artwork also blurs and fades over time you may be disappointed with its eventual appearance Skin disorders Your body may form bumps called granulomas around tattoo ink especially if your tattoo includes red ink Tattooing can also cause areas of raised excessive scarring called keloids Keloids are more common in those with darker skin Skin infections Tattoos and piercings can lead to local bacterial infections Typical signs and symptoms of a skin infection include redness warmth swelling and a discharge containing pus Significant skin infections after tattooing are unusual However up to 30 percent of piercings result in such infections or bleeding Navel piercings take longer to heal sometimes up to nine months since sweat under tight clothing can keep the area damp increasing bacteria Infections from piercings in the upper ear cartilage are especially serious Since cartilage doesn t have its own blood supply taking antibiotics is often ineffective the drug can t travel to the infection site Such infection can lead to cartilage damage and serious