Micro special topics 1

HIV

retrovirus, or a RNA-based virus that converts into viral DNA when within a host, destroys enough of the immune system that any microbe is capable of infecting the individual.​

AIDS

(Acquired immunodeficiency syndrome) is a disorder in which the individual’s immune system is progressively destroyed by the human

Current treatment options for AIDS

• Reverse transcriptase inhibitors block the viral RNA from being converted into DNA.​

• Protease inhibitors block the assembly of HIV protein capsids.​

• Integrase inhibitors prevent viral DNA from being inserted into cellular DNA.​

Vesticle

small fluid-filled lesion less than 1 cm in diameter.​

Bulla

a fluid-filled lesion larger than 1 cm in diameter.​

Macule

flat, reddish lesion

papule

elevated lesion.​

pustule

papule that contains pus.

Describe impetigo, including its symptoms, causative microbes, methods of transmission, and treatment options

highly contagious infection of the epidermis that causes the formation of pustules that rupture and form light-colored crusts.​

• commonly caused by Staphylococcus aureus, and less commonly by Streptococcus pyogenes.​

• Transmission is through direct physical contact, usually through a break in the skin.​

• Treatment involves application of topical antibiotics, though the lesions often heal without treatment.​

Describe erysipelas, including its symptoms, causative microbes, methods of transmission, and treatment options

is an infection of the dermis by Streptococcus pyogenes.​

• lesion has a distinct reddish and hardened appearance, with elevated edges, and is caused by beta-hemolytic exotoxins from S. pyogenes.​ other symptoms include fever and chills.​

• Treatment includes the use of antibiotics, including penicillins

Explain the causes of necrotizing fasciitis, its pathogenesis, and treatment options.

inflammation of connective tissue that leads to necrosis, or premature death of cells in living tissue.​

• streptococcal infection, Another species contributing to cases of necrotizing fasciitis is methicillin-resistant S. aureus.​

• Treatment includes broad-spectrum antibiotics, removal of necrotic tissue, and amputation.

Explain the causes of ringworm, methods of transmission, and treatment options.

Not caused by a parasitic worm, but by a mycosis, or fungal infection.​

• usually transmitted through fomites and animal vectors.

• Treatment includes the use of azoles (miconazole and clotrimazole) and allylamines (terbinafine, naftifine, and butenavine).​

Define encephalitis

an infection of the brain itself

Define meningitis

an infection of the meninges of the central nervous system, and can be caused by many different pathogens.​

List and describe the four bacterial species best known for causing bacterial meningitis.

Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae (now the leading cause)​, Listeria monocytogenes

Describe leprosy, including its symptoms, causative microbes, and treatment options.

a progressive disease that damages nervous tissue through a cell-mediated immune response.​

• caused by Mycobacterium leprae and Mycobacterium lepromatosis

• Secondary infections can cause numbness and tissue loss in body regions.​

• Treatment involves a multidrug regimen including clofazimine, dapsone, and rifampicin.​

Describe rheumatic fever, including its symptoms, causative microbes, and treatment options.

cell-mediated attack against connective tissue in joints and the myocardium.​

• Symptoms include migratory arthritis, inflammation of heart tissue, and the formation of subcutaneous nodules.​

• Treatment involves anti-inflammatory drugs and low-dose antibiotics.​

Describe anthrax, including its symptoms, causative microbes, methods of transmission, and treatment options

caused by two A-B exotoxins released by the bacterium Bacillus anthracis.​

• Anthrax is a zoonosis.​

• Infection usually occurs through direct contact, inhalation, or ingestion of anthrax endospores.

• Symptoms include low-level fever and the formation of a distinctive black scab; sepsis is rare.​

• Treatment options include ciprofloxacin (a fluoroquinolone), doxycycline (a tetracycline), and raxibacumab (a monoclonal antibody).​

Explain how the anthrax exotoxins function, and how human anthrax vaccine is generated.

• Edema toxin causes swelling, and interferes with phagocytosis.​

• Lethal toxin targets and kills macrophages.​

Describe plague, including its symptoms, reservoirs, causative microbes, methods of transmission, and treatment options.

• Yersinia pestis is responsible for plague, or the Black Death.​

• Transmission is usually through arthopod vectors (fleas), but can spread via direct contact as well

• Symptoms include hemorrhage, fever, the swelling of lymph nodes, and necrosis.​

• Antibiotics and vaccines are readily available.​

• Drugs must be administered before the infection overwhelms the host.

Describe Lyme disease, including its symptoms, reservoirs, causative microbes, methods of transmission, and treatment options

• caused by the bacterium Borrelia burgdorferi, a spirochete.

• Symptoms include a distinctive rash, heart disorders, arthritis, and neuropathy.​

• Primary reservoirs are field mice and deer, with deer ticks serving as the vector.

• Antibiotics may be effective when administered early.​

List and describe the four viral families that are responsible for viral hemorrhagic fever.

• Arenaviridae—responsible for Lassa fever.​

• Bunyaviridae—includes Hantavirus, and often causes hemorrhagic fever with renal syndrome.​

• Filoviridae—includes Ebola and Marburg viruses.​

• Flaviviridae—includes yellow fever, dengue, and West Nile viruses.​

Describe the symptoms of viral hemorrhagic fever, and current potential treatment options.

Symptoms include fever, excessive bleeding (due to inability to clot), and shock.​

• Ribavarin, an antiviral drug (nucleoside agent), is effective against some strains of viral hemorrhagic fever, especially flaviviridae members.​

• The use of convalescent plasma, or plasma from patients that have survived hemorrhagic fever, has seen some success.​ (Not FDA approved)