MICRO III - Exam 6 (dated material)

Common cold

- AKA coryza - an acute viral infection of the upper respiratory tract - transmitted via droplet spray or direct contact with nasal secretions - characterized by: - fever - runny nose - mild sore throat - runny eyes - nasal congestion

Rabies

- AKA hydrophobia - it or an acute encephalomyelitis - transmitted to humans through the saliva of an infected animal via a bite - could possibly enter through open wounds, abrasions or mucous membranes - there are two forms of the disease: - Furious rabies - Paralytic rabies

German measles

- AKA rubella or 3 day measles - milder form of measles then rubeola - also transmitted by direct contact with nasal or throat secretions of infected individuals - causes pale pink rash & slight fever - this rash also begins at the head & moves downward - is most dangerous in pregnant women during the first trimester - will cause miscarriages, still births or several serious birth defects

Measles

- AKA rubeola or red measles - acute, highly contagious disease - 1 of most contagious of childhood rash diseases - transmitted by direct contact with nasal or throat secretions of infected individuals - rash begins at head & moves downward - Koplik spots form on gums & inside of cheeks - small white spots - can be controlled with vaccinations MMR - measles, mumps, rubella

Chicken pox

- AKA varicella-zoster virus - same virus causes shingles in adults - transmitted via droplet spray or through the vesicular fluid of the lesions - chickenpox is more readily transmitted than shingles - causes generalized itchy vesicular rash - begins as smooth red spots that develop into blisters that last 3 or 4 days before forming crusts - there may also be a fever & general ill feeling - this rash tends to appear in 2-4 successive crops rather than all at once - the lesions may appear nearly anywhere - scalp - mouth - upper respiratory - conjunctive - cornea - vagina

Infectious mononucleosis

- Mono caused by Epstein-Barr virus - an acute disease characterized by: - fever - sore throat - malaise - enlargement of the lymph nodes - & possibly the spleen - occurs mainly in young adults 15-30 - transmitted with direct contact with infected saliva - because of this it is often known as: - kissing disease - person may remain infectious for as long as a year after recovery - there is no treatment other than rest

Influenza

- a common upper respiratory viral infection - usually called the flu - transmitted via droplet spray or direct contact with nasal secretions - characterized by: - muscle pain - high fever - chills - runny nose - cough - sore throat

Hepatitis C

- also known as Non-A Non-B hepatitis - also transmitted through contaminated body fluids - even more serious because there is not yet a vaccine available - Hep G found to mimic Hep C

Hepatitis A

- also known as infectious hepatitis - spread directly from person to person by the fecal oral route - due to poor sanitation methods - not as serious as other forms

Hepatitis B

- also known as serum hepatitis - transmitted through contaminated body fluids - represents an occupational hazard to people who work with blood & blood products - more serious than hepatitis A - may result in chronic hepatitis & permanent liver damage - hepatitis D is defective virus that must have Hep B present to infect - can lead to super infection if both are present - leading to exacerbation of chronic hepatitis

Viral encephalitis

- an acute inflammation of the brain caused by a virus - transmitted by bite of mosquitoes or sometimes tics & fleas - the arthropod vector acquires the virus by biting an infected individual - viruses replicate in vectors & move to salivary glands - it is then spread to another person when the vector bites them - most cases are asymptomatic - those that do exhibit symptoms include: - fever - pain - neck stiffness - headache - loss of energy - this can easily progress into an even more serious form that includes: - loss of muscle power - double vision - speech impairment - coma - fatality rate up to 60%

Creutzfeldt-Jakob Disease (CJD)

- caused by protein particle called a PRYON - are protein the folded into a unique 3 dimensional form - they cause other proteins in their presence to conform also - cause a group of diseases called "slow" virus diseases - the diseases exhibit some characteristics common to viral diseases - no evidence of a virus found - the diseases manifest as uncommon degenerative diseases of the central nervous system - these are called spongiform encephalopathies - the most well-known are: - bovine spongiform encephapathies (MAD COW) - most evident symptom in humans is dementia - usually affects adults 50-75 years of age

AIDS

- caused by the HIV, human immunodeficiency, virus - a group of clinical conditions in which there is a dramatic change in the host's susceptibility to opportunistic disease by a reduction in immune defense - affects the Ty helper cells of immune system - causes the inability of the host to mount the full spectrum of immune responses needed to ward off opportunistic infections & cancer cells - the opportunistic infections most often associated with HIV infection are: - pnuemoniacystis carinni - Kaposi's Sarcoma (skin cancer) - cidiasis (thrush) - crytococcal meningitis (fungal infection) - cytomegalovirus infection - encephalitis

Smallbox

- caused by viriola virus - transmitted via droplet spray or contaminated fomite - virus is very hardy; can survive on fomites longer - causes sudden appearance of skin rash that progresses thru a series of stages that ends w/lesions scabbing over & falling off after about 3/4 weeks - disease has been eradicated worldwide by vaccinations

Cytomegalovirus

- causes cytomegalic inclusion disease - a disease of the glands such as the salivary glands or the liver - asymptomatic in most cases - causes infection mono like in others - establish latent infection like that of Herpes - the cells infected with the virus swell in size "cyto" - "megalo" - & inclusion bodies develop in the cytoplasm & nucleus - transmitted via direct contact with: - saliva - semen - cervical secretion - urine - blood - also via congenital transmission - most serious in immune compromised individuals

Hantavirus

- causes severe life threatening respiratory disease - first recognized in 1993 in the "Four Corners" area of the United States - where New Mexico, Arizona, Utah & Colorado meet - transmitted to humans by inhalation of dried fecal, urine or saliva of long tailed deer mouse - could possibly enter through open wounds, abrasions or by ingestion as well - the disease starts out as a nondescript flu-like illness with fever, muscle aches, & coughing - then suddenly back pain develops, indicating lung problems - lungs rapidly deteriorating & filling with fluid - death follows soon after due to respiratory failure or shock - usually 5-7 days till death

Poliomyelitis

- central nervous system disease affecting motor neurons of spinal cord - transmitted via the fecal-oral route or contact with nasal/oral secretions - begins as gastro intestinal disturbance most people do not pass this point - may then progress to various levels of disease - one of which may be the well known paralytic polio - disease controlled by Salk & Rabin vaccines - it is a goal of the World Health Organization to declare the world eradicated of polio in the next few years

Epidemic parotitis or mumps

- gets its name from the infection of the parotid glands - salivary glands located anterior & inferior to ear - may affect other salivary glands as well - occurs most commonly in children 2-12 years of age - causes swelling & tenderness of glands - spread by droplet spray or direct contact with infected saliva - if infection occurs in post-pubescent males, it may cause an inflammation of the testes called: - orchitis - controlled with MMR vaccine

Furious rabies

- manifests itself with bizarre behavior ranging from severe agitation to periods of depression - confusion becomes more extreme & disease progresses - person becomes very aggressive - hydrophobia develops - hyper salivation occurs - 1 to 1/12 liters per 24 hours - excessive sweating - a coma ensues & death occurs usually within 7 to 10 days following the onset of symptoms

Paralytic rabies

- paralysis begins at point of bite - it then spreads to the rest of the body - finally affects the pharyngeal & respiratory muscle causing death

Herpes simplex I & II

- recurrent viral infection - forms vesicles at the affected site - after first infection the individual becomes a carrier - virus remains latent in nerve sheaths of sensory nerves - recurrences will continue for life - often triggered by: - stress - fever - menstrual cycle - overexposure to the sun

VIRUSES

- smallest, simplest forms of life known - requires electron microscope to see them - some consider them to not be alive because they cannot metabolize their own energy or reproduce themselves w/o components of another living cell - obligate intracellular parasites - they pass thru biological filters that would retain bacteria because of their size - most antibiotics work by interrupting metabolism of bacteria but this doesn't affect viruses - basic structure of a virus includes: - nucleic acid core - composed of DNA or RNA - core surrounded by protein coat called a capsid - capsid composed of individual structured sub units called capsomers - some viruses also have envelopes around capsid - comes from host cell nuclear or protoplasmic membrane as virus exits after replication - mature infection viruses called virions - numerous ways to classify viruses; we will do so according to tissue of preferred growth

Herpes simplex I - Type I

- transmitted by oral respiratory secretions - affects the skin & mucus membranes - causes cold sores or fever blisters

Herpes simplex II - Type II

- transmitted by sexual contact - affects genital area - causes similar lesions as in Type I - there is no cure for this infection - individual will remain & carries for life

Important Viral Diseases

1. Dermotropic diseases 2. Pneumotropic diseases 3. Neurotropic diseases 4. Viscerotropic diseases 5. Adenotropic 6. Immunotropic (Immunological) disease & Prion-caused disease

Shingles

AKA herpes-zoster - also caused by verisicular zoster virus that is reactivated - the same virus that causes chickenpox in children - can be transmitted via droplet spray or through the vesicular fluid of the lesions - but not as easily as chickenpox - the vesicles occur along skin areas supplied by the certain sensory nerves - occurs unilaterally - most prominent on head, neck & upper torso - occurs primarily in older adults & immunocompromised individuals - causes localized numbness, tingling & severe pain - no treatment available except to treat the symptoms after contracting the disease - there is now a vaccine available for at-risk people

Viscerotropic diseases

a) Hepatitis A b) Hepatitis B c) Hepatitis C

Immunotropic (Immunological) disease & Prion-caused disease

a. AIDS b. Creutzfeldt-Jakob Disease (CJD)

Adenotropic

a. Epidemic parotitis or mumps b. Infectious mononucleosis c. Cytomegalovirus

Pneumotropic diseases

a. Influenza b. Common cold c. Hantavirus

Neurotropic diseases

a. Rabies b. Poliomyelitis c. Viral encephalitis

Dermotropic diseases

a. Smallpox b. Measles c. German measles d. Chicken pox e. Shingles f. Herpes simplex I & II

Neurotropic diseases

central nervous system diseases

Viscerotropic diseases

diseases affecting the viscera Hepatitis A, B, & C

Pneumotropic diseases

diseases of the respiratory tract

Dermotropic diseases

diseases of the skin

Adenotropic

glandular diseases Epidemic parotitis or mumps Infectious mononucleosis Cytomegalovirus