Whooping Cough (Pertussis)

Overview and Etiology

Whooping cough is a highly contagious respiratory disease caused by Bordetella pertussis, a gram-negative coccobacillus.

• Transmission: Airborne droplets

• General Disease Info: Primarily affects children; characterized by prolonged coughing fits followed by a "whooping" sound during inhalation.

• Vaccine: DTaP for children, Tdap for older individuals

• Toxin: AB toxin

• Zoonotic: No

• Nationally Notifiable: Yes

• Emerging Infectious Disease: Re-emerging due to lowered vaccination rates

Key Points

• Symptoms: Severe coughing fits, inspiratory "whoop"

• Prevention: Vaccination is critical for control

Gonorrhea

Overview and Etiology

Gonorrhea is a sexually transmitted infection caused by Neisseria gonorrhoeae, a gram-negative diplococcus.

• Transmission: Sexual contact, vertical (mother to child)

• General Disease Info: Purulent discharge in males; often asymptomatic in females. Can lead to Pelvic Inflammatory Disease (PID) and complications in pregnancy.

• Vaccine: None

• Zoonotic: No

• Nationally Notifiable: Yes

• Emerging Infectious Disease: No

Key Points

• Symptoms: Urethral discharge, dysuria

• Complications: PID, infertility

Strep Throat (Pharyngitis) and Scarlet Fever

Overview and Etiology

Strep throat and Scarlet fever are caused by Streptococcus pyogenes, a gram-positive coccus that produces beta hemolytic colonies.

• Transmission: Direct and droplet communication

• General Disease Info: Ranges from mild sore throat to high fever

• Unique Symptoms: Scarlet fever presents with a sandpaper rash, high fever, and "strawberry tongue"

• Toxin: Streptococcal Pyrogenic Exotoxin (SPE)

• Vaccine: None; too many serovars for effective vaccine

• Zoonotic: No

• Nationally Notifiable: No

• Emerging Infectious Disease: No

Key Points

• Symptoms: Sore throat, fever, rash (scarlet fever)

• Complications: Rheumatic fever, glomerulonephritis

Pneumococcal Pneumonia

Overview and Etiology

Pneumococcal pneumonia is a common cause of community-acquired pneumonia, especially in older adults, caused by Streptococcus pneumoniae, a gram-positive coccus.

• Transmission: Direct contact/droplets

• General Disease Info: Most severe in older adults; symptoms include chest pain, cough, and pleuritic pain.

• Vaccine: Pneumococcal conjugate vaccines (PCV13, PCV23)

• Toxin: Cytolysin

• Zoonotic: No

• Nationally Notifiable: No

• Emerging Infectious Disease: No

Key Points

• Symptoms: Productive cough, chest pain, fever

• Prevention: Vaccination for high-risk groups

Lyme Disease

Overview and Etiology

Lyme disease is a tick-borne illness caused by Borrelia burgdorferi, a gram-negative spirochete.

• Transmission: Tick bites (Ixodes species)

• General Disease Info: Early symptoms include bull's-eye rash (erythema migrans), fever, and joint pain. If untreated, can spread to joints, heart, and nervous system.

• Vaccine: No; LYMErix was discontinued in 2002

• Zoonotic: Yes

• Toxin: No

• Nationally Notifiable: Yes

• Emerging Infectious Disease: Yes

Key Points

• Symptoms: Erythema migrans, fever, joint pain

• Prevention: Avoidance of tick habitats, prompt removal of ticks

Tuberculosis (TB)

Overview and Etiology

Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis, an acid-fast bacillus.

• Transmission: Airborne/droplet

• General Disease Info: Diagnosed by tuberculin skin test (TST) or blood test; chest X-rays show granulomas (tubercles).

• Vaccine: BCG (not available in US)

• Unique Symptoms: Latent TB infection (LTBI) possible

• Zoonotic: No

• Nationally Notifiable: Yes

• Emerging Infectious Disease: Yes

Key Points

• Symptoms: Chronic cough, weight loss, night sweats

• Diagnosis: TST, blood test, chest X-ray

Rocky Mountain Spotted Fever

Overview and Etiology

Rocky Mountain Spotted Fever is a tick-borne disease caused by Rickettsia rickettsii, a very small gram-negative rod.

• Transmission: Tick bites

• General Disease Info: Obligate intracellular parasite; high fever and rash, can cause toxic shock syndrome with high mortality.

• Vaccine: None

• Zoonotic: Yes

• Nationally Notifiable: Yes

• Emerging Infectious Disease: No

Key Points

• Symptoms: Fever, rash, headache

• Complications: Toxic shock, organ failure

Chlamydia

Overview and Etiology

Chlamydia is a common sexually transmitted infection caused by Chlamydia trachomatis, a small gram-negative coccobacillus.

• Transmission: Sexual contact, vertical

• General Disease Info: Obligate intracellular parasite; often asymptomatic, can lead to PID.

• Vaccine: None

• Zoonotic: No

• Nationally Notifiable: Yes

• Emerging Infectious Disease: No

Key Points

• Symptoms: Urethritis, cervicitis, PID

• Complications: Infertility, ectopic pregnancy

Antibiotic Associated Diarrhea (C. diff)

Overview and Etiology

Antibiotic associated diarrhea is caused by Clostridium difficile, a gram-positive bacillus that forms spores and is anaerobic.

• Transmission: Direct or indirect fecal-oral transmission, fecal smear

• General Disease Info: Mild to severe diarrhea and colitis

• Toxins: Toxin A and Toxin B

• Vaccine: None

• Zoonotic: No

• Nationally Notifiable: No

• Emerging Infectious Disease: No

Key Points

• Symptoms: Severe diarrhea, colitis, dehydration

• Complications: Toxic megacolon, death

Summary Table: Major Bacterial Diseases