Infectious Diseases (MICRO)

Necrotizing fasciitis Causative Agent ​

Streptococcus pyogenes or Staphylococcus aureus

Necrotizing fasciitis Signs / Symptoms

Hot, intensely painful, sunburn-like rash at the site of infection is followed by fever, tiredness, and muscle aches.

As tissue is destroyed, blood pressure drops and patients become mentally confused and ultimately comatose.

Necrotizing fasciitis Treatment / Prevention

Powerful broad-spectrum antibiotics and removal of dead tissue.

Amputation is needed in severe cases. 

Smallpox causative agent

variola virus

Chickenpox causative agent

human herpes virus type 3 or varicella-zoster virus.

Chickenpox Signs / Symptoms

itchy vesicles filled with clear fluid that are spread over the body.​

Rubella (German measles) signs and symptoms

Mild rash of pink to red macules, fever, and swollen lymph nodes.​ ​

Measles (rubeola) complications

laryngitis, bronchopneumonia, and secondary bacterial infections. The most severe complication is subacute sclerosing panencephalitis (SSPE)

Rubella (German measles) causative agent

rubella virus

Measles (Rubeola) causative agent

measles virus

Measles (Rubeola) Signs / Symptoms

Fever, sore throat, headache, dry cough, conjunctivitis, Red maculopapular rash, Koplik's spots appear on the mucous membrane of the mouth.

Bacterial Meningitis causative agents

Neisseria meningitidis ​

Streptococcus pneumoniae ​

Hemophilus influenzae ​

Streptococcus agalactiae ​

Listeria monocytogenes 

Bacterial Meningitis signs/symptoms

increased number of white blood cells in the cerebrospinal fluid (CSF)

sudden high fever

intense meningeal inflammation

Botulism causative agent

Clostridium botulinum

Tetanus causative agent

Clostridium tetani

Botulism Signs / Symptoms ​

Toxin travels from the bloodstream to the neuromuscular junctions of skeletal muscles. ​Prevents the release of acetylcholine, ​resulting in flaccid paralysis. ​

Botulism Prevention

Food hygiene

Tetanus Signs / Symptoms ​

Tightening of the jaw and neck muscles.​ ​Blocks the inhibition of muscle contraction,​ causing muscles to contract uncontrollably,​ resulting in spastic paralysis. ​Death results from paralysis of respiratory​ muscles and respiratory arrest.

Tetanus Prevention

vaccination with tetanus toxoid TDaP

Rabies causative agent

rabies virus

Rabies treatment

It can be treated after exposure to the virus if treatment begins immediately. The therapy includes passive immunization with human rabies immune globulin and active immunization with the rabies vaccine.​​

Variant Creutzfeldt-Jakob Disease ​( vCJD ) ​ causative agent

Prion protein

Variant Creutzfeldt-Jakob Disease ​( vCJD ) Signs/Symptoms

Brain tissue is destroyed, resulting in insomnia, weight loss, and memory failure. Patients act irrationally, lose control of their muscles, and are unable to speak, walk, or maintain posture. This usually occurs within 12 months. ​

Variant Creutzfeldt-Jakob Disease ​( vCJD ) Prevention

​Avoiding infected meat and proper sterilization of instruments can prevent this disease.​

Sepsis Signs/Symptoms

Fever, chills, nausea, vomiting, shortness of breath, malaise, and changes in mental status characterize sepsis. Symptoms can progress rapidly to septic shock, a life-threatening condition of extremely low blood pressure resulting from the dilation of blood vessels.

Bacterial sepsis can also trigger minute skin lesions, known as petechiae, on the trunk and lower extremities. In some instances, bacteria invade bones to cause osteomyelitis, inflammation of the bones and bone marrow. ​

Infectious endocarditis Causative agents

Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Enterococcus

Infectious endocarditis Symptoms

fever, fatigue, malaise, difficulty breathing, tachycardia, and murmurs

Infectious endocarditis Treatment/Prevention

Broad-spectrum antibiotics. Surgery in some cases.

Prevention involves prophylactic antibiotics before invasive procedures

Lyme Disease Causative Agent ​

Borrelia burgdorferi

Lyme Disease Signs / Symptoms

bull’s-eye rash at the infection site, neurological symptoms, and severe arthritis.

COVID-19 Causative Agent

SARS-CoV-2

COVID-19 Signs / Symptoms

Respiratory symptoms, cytokine storm, skin rashes, joint and muscle pain, heart damage, blood clots, vomiting, and diarrhea.

Pharyngitis Causative Agent

Streptococcus pyogenes

Pharyngitis Symptoms

sore throat and difficulty swallowing, often accompanied by fever, malaise, and headache. May progress to scarlet fever. Acute glomerulonephritis occurs in some untreated cases.

Influenza Causative Agent

Influenza A, B, and C viruses

Influenza Symptoms

Pharyngitis, nasal discharge, cough, myalgia, and Sudden fever.

Patients are susceptible to secondary bacterial infections.

Tuberculosis Causative Agent

Mycobacterium tuberculosis

Tuberculosis Symptoms

Initially limited to a minor cough and mild fever. Symptoms are not always apparent. Symptoms of secondary tuberculosis are more severe.

Pertussis (whooping cough) Causative Agent

Bordetella pertussis

Pertussis (whooping cough) Symptoms

Runny nose, persistent cough with whoops, coughing can burst blood vessels in the eyes and brain. Vomiting and seizures can happen

Peptic ulcers Causative Agent

Heliobacter pylori

Peptic ulcers Symptoms

Gastritis with sharp or burning pain emanating from the abdomen. A long-term infection with this bacterium can lead to stomach cancer​.

Peptic ulcers Treatment

Antibiotics and acid suppression

Gastroenteritis (STEC) Causative Agent

Shiga-toxin-producing Escherichia coli (STEC)

Gastroenteritis (STEC) Symptoms

Mild gastroenteritis with fever, bloody diarrhea, and hemolytic uremic syndrome.​

Gastroenteritis (STEC) Treatment / Prevention

Fluid and electrolyte replacement. Plasma transfusion to dilute the toxin.

Cooking food to recommended temperatures and washing vegetables thoroughly.

Traveler's diarrhea (ETEC) Causative Agent

Enterotoxigenic ​​​​​​Escherichia coli

Traveler's diarrhea (ETEC) Symptoms

Watery diarrhea, low-grade fever, nausea, and vomiting.

Traveler's diarrhea (ETEC) Treatment / Prevention

Self-limiting illness treated with fluid and electrolyte replacement.

Avoid contaminated foods and drinks.

Clostridium difficile Symptoms

Watery, foul-smelling bowel movements

Vaginitis “yeast infection” Causative Agent

Candida albicans

Vaginitis “yeast infection” Symptoms

itching and burning and discharge.

Sexual intercourse can be very painful.

The vaginal discharge is often white and curd-like.

Syphilis Causative Agent

Treponema pallidum

Syphilis Symptoms

Primary: hard, non-painful, genital chancre that disappears after 3–6 weeks.

Secondary: sore throat, headache, mild fever, malaise, myalgia, and rash that lasts several weeks or months. Latent syphilis: generally asymptomatic, lasts for decades.

Tertiary: dementia, blindness, paralysis, and gumma lesions.

Syphilis Treatment / Prevention

Penicillin G early in the disease

Treatment of sexual contacts

Condom usage