Severe Acute Respiratory Syndrome (SARS) is a respiratory illness caused by a previously unknown type of coronavirus. Normally, coronaviruses cause mild to moderate upper respiratory symptoms, such as the common cold. SARS is new, and scientists are still searching for answers to many questions about this illness.
Avian influenza is an infectious disease of birds caused by type A strains of the influenza virus. The disease, which was first identified in Italy more than 100 years ago, occurs worldwide.
All birds are thought to be susceptible to infection with avian influenza, though some species are more resistant to infection than others. Infection causes a wide spectrum of symptoms in birds, ranging from mild illness to a highly contagious and rapidly fatal disease resulting in severe epidemics.
Avian influenza viruses do not normally infect species other than birds and pigs. The first documented infection of humans with an avian influenza virus occurred in Hong Kong in 1997, when the H5N1 strain caused severe respiratory disease in 18 humans, of whom 6 died. The infection of humans coincided with an epidemic of highly pathogenic avian influenza, caused by the same strain, in Hong Kong’s poultry population.
Clostridium difficile is a spore forming bacteria which can be part of the normal intestinal flora in as many as 50% of children under age two, less frequently in older individuals. C.difficile is the major cause of pseudomembranous colitis and antibiotic associated diarrhea. C. difficile-associated disease occurs when the normal intestinal flora is altered, allowing C.difficile to flourish in the intestinal tract and produce a toxin that causes a watery diarrhea.
Methicillin-resistant Staphylococcus Aureus (MRSA) is a type of bacteria that is resistant to certain antibiotics. These antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin and amoxicillin. Staph infections, including MRSA, occur most frequently among persons in hospitals and healthcare facilities (such as nursing homes and dialysis centers) who have weakened immune systems.
Vancomycin-Resistant Enterococcus (VRE) is a mutant strain of Enterococcus that originally developed in individuals who were exposed to the antibiotic. It was first identified in Europe in 1986, and in the U.S. in 1988. Enterococcus are bacteria that live in the digestive and genital tracts. They are normally benign and don’t cause any problems in healthy people. Vancomycin is a powerful antibiotic that is often the antibiotic of last resort. It is generally limited to use against bacteria that are already resistant to penicillin and other antibiotics.