Summary Table of Infectious Diseases: Causative Agents, Transmission, Virulence, and Prevention

Overview of Infectious Diseases

This study guide summarizes key infectious diseases, focusing on their causative agents, modes of transmission and prevention, unique virulence factors or signs/symptoms, vaccine availability, and other relevant clinical or epidemiological information. The information is organized in a comparative table for efficient review and exam preparation.

Disease	Causative Agent	Transmission / Prevention	Unique Virulence Factors or Signs/Symptoms	Vaccine?	Other Info (System affected, epidemiology, etc.)
Respiratory Syncytial Virus (RSV)	Respiratory syncytial virus (RSV): enveloped, single-stranded RNA genome, Pneumoviridae family	Transmitted by respiratory droplets and fomites; prevention includes sanitary practices and hand washing; antibody injections for high-risk groups (especially premature infants)	Coughing, sneezing, fever; wheezing may occur	About 60 vaccine candidates in development; antibody preparations for high-risk patients	Endemic among children under age 5; dangerous in premature infants, immunocompromised, or those with chronic lung/heart conditions; most cases from fall through early spring; incubation 4–6 days; affects respiratory system
Pertussis (Whooping Cough)	Bordetella pertussis (Gram-negative coccobacillus)	Respiratory droplets; DTaP/Tdap vaccine; isolation of infected individuals	Paroxysmal cough with "whoop" sound; pertussis toxin; catarrhal and paroxysmal stages	DTaP/Tdap (acellular pertussis vaccine)	Primarily affects children; can be severe in infants; respiratory system
Influenza	Influenza virus (Orthomyxoviridae; segmented, negative-sense RNA)	Respiratory droplets, fomites; annual vaccination; hand hygiene	Fever, myalgia, cough, sore throat; antigenic drift and shift	Annual inactivated/live-attenuated vaccines	Seasonal epidemics; respiratory system; can cause pandemics
Tuberculosis	Mycobacterium tuberculosis (acid-fast bacillus)	Airborne droplets; BCG vaccine (not used in all countries); isolation, treatment with multi-drug regimen	Chronic cough, hemoptysis, night sweats, weight loss; granuloma formation	BCG (Bacillus Calmette–Guérin)	Primarily affects lungs; can be latent or active; high global burden
Chickenpox/Shingles	Varicella-zoster virus (VZV; Herpesviridae)	Respiratory droplets, direct contact; varicella vaccine; shingles vaccine for older adults	Vesicular rash (chickenpox); dermatomal rash (shingles); latency in dorsal root ganglia	Varicella (children), Zoster (adults)	Chickenpox in children; shingles in older adults; skin and nervous system
Measles	Measles virus (Paramyxoviridae; enveloped, negative-sense RNA)	Respiratory droplets; MMR vaccine	Koplik spots, maculopapular rash, high fever, cough, coryza, conjunctivitis	MMR (measles, mumps, rubella)	Highly contagious; respiratory and integumentary systems
Trachoma	Chlamydia trachomatis (obligate intracellular bacterium)	Direct contact, fomites, flies; improved sanitation, antibiotics	Chronic conjunctivitis, eyelid scarring, blindness	No vaccine	Leading cause of infectious blindness; affects eyes
Rabies	Rabies virus (Rhabdoviridae; bullet-shaped, negative-sense RNA)	Animal bites (saliva); post-exposure prophylaxis (PEP) vaccine	Hydrophobia, agitation, paralysis, fatal encephalitis	Rabies vaccine (pre- and post-exposure)	Almost always fatal once symptoms appear; nervous system
West Nile Encephalitis	West Nile virus (Flaviviridae; enveloped, positive-sense RNA)	Mosquito vector (Culex spp.); mosquito control	Fever, headache, encephalitis, meningitis in severe cases	No human vaccine	Can cause neuroinvasive disease; nervous system
Polio	Poliovirus (Picornaviridae; non-enveloped, positive-sense RNA)	Fecal-oral; inactivated (IPV) and oral (OPV) polio vaccines	Asymptomatic or paralytic poliomyelitis	IPV, OPV	Eradicated in most countries; nervous system
Botulism	Clostridium botulinum (Gram-positive, spore-forming anaerobe)	Foodborne (improperly canned foods), wound, infant; proper food handling	Flaccid paralysis due to botulinum toxin	No vaccine; antitoxin available	Neurotoxin; nervous system
Hepatitis A	Hepatitis A virus (Picornaviridae; non-enveloped, positive-sense RNA)	Fecal-oral; inactivated vaccine; improved sanitation	Acute hepatitis, jaundice, fever, nausea	Hepatitis A vaccine	Liver; does not cause chronic infection
Stomach Ulcers	Helicobacter pylori (Gram-negative, spiral-shaped bacterium)	Oral-oral, fecal-oral; hygiene, antibiotics	Gastric inflammation, peptic ulcers, urease production	No vaccine	Digestive system; risk factor for gastric cancer
Campylobacteriosis	Campylobacter jejuni (Gram-negative, curved rod)	Contaminated food/water (especially poultry); proper cooking	Diarrhea (often bloody), abdominal cramps, fever	No vaccine	Digestive system; common cause of bacterial gastroenteritis
Enterohemorrhagic E. coli (EHEC)	Escherichia coli O157:H7 (Gram-negative rod)	Contaminated food/water; proper food handling	Bloody diarrhea, hemolytic uremic syndrome (HUS); Shiga toxin	No vaccine	Digestive system; can cause kidney failure
Hepatitis B	Hepatitis B virus (Hepadnaviridae; enveloped, partially double-stranded DNA)	Blood, sexual, perinatal; recombinant vaccine	Acute and chronic hepatitis, cirrhosis, hepatocellular carcinoma	Hepatitis B vaccine	Liver; can cause chronic infection
Chlamydia	Chlamydia trachomatis (obligate intracellular bacterium)	Sexual contact; condom use, screening, antibiotics	Often asymptomatic; urethritis, cervicitis, pelvic inflammatory disease	No vaccine	Urinary/reproductive systems; most common bacterial STI
Gonorrhea	Neisseria gonorrhoeae (Gram-negative diplococcus)	Sexual contact; condom use, antibiotics	Urethritis, cervicitis, discharge; can be asymptomatic	No vaccine	Urinary/reproductive systems; antibiotic resistance is a concern
Trichomoniasis	Trichomonas vaginalis (flagellated protozoan)	Sexual contact; condom use, antiprotozoal drugs	Vaginitis, frothy discharge, itching	No vaccine	Urinary/reproductive systems; common non-viral STI
HPV (Human Papillomavirus)	Human papillomavirus (non-enveloped DNA virus)	Sexual contact; HPV vaccine (Gardasil, Cervarix)	Genital warts, cervical and other cancers	HPV vaccine (Gardasil, Cervarix)	Urinary/reproductive systems; oncogenic strains
Rocky Mountain Spotted Fever	Rickettsia rickettsii (obligate intracellular bacterium)	Tick vector (Dermacentor spp.); tick avoidance, prompt removal	Fever, headache, petechial rash, can be fatal	No vaccine	Cardiovascular/lymphatic systems; southeastern US
Malaria	Plasmodium spp. (protozoan parasite)	Anopheles mosquito vector; bed nets, antimalarial drugs	Fever, chills, anemia, cycles of symptoms	RTS,S/AS01 (Mosquirix) in some regions	Cardiovascular/lymphatic systems; high global burden
Lyme Disease	Borrelia burgdorferi (spirochete bacterium)	Ixodes tick vector; tick avoidance, prompt removal	Erythema migrans (bull's-eye rash), arthritis, neurological symptoms	No vaccine (human)	Cardiovascular/lymphatic, nervous, musculoskeletal systems; endemic in NE US
Ebola	Ebola virus (Filoviridae; enveloped, negative-sense RNA)	Direct contact with body fluids; infection control, rVSV-ZEBOV vaccine	Hemorrhagic fever, high mortality, multi-organ failure	rVSV-ZEBOV (Ervebo)	Cardiovascular/lymphatic systems; outbreaks in Africa

Key Concepts and Additional Information

• Virulence Factors: Many pathogens produce toxins, enzymes, or have structural adaptations (e.g., capsules, antigenic variation) that enhance their ability to cause disease.

• Vaccines: Vaccines are available for several diseases (e.g., influenza, measles, polio, HPV, hepatitis A/B, rabies, varicella, Ebola, malaria in some regions). For others, prevention relies on hygiene, vector control, or safe practices.

• Transmission: Modes include respiratory droplets, direct contact, sexual contact, vectors (mosquitoes, ticks), and contaminated food/water.

• Systems Affected: Diseases are classified by the primary system affected (respiratory, nervous, digestive, urinary/reproductive, cardiovascular/lymphatic, skin/eye).

Example: RSV (Respiratory Syncytial Virus)

• Definition: RSV is a common respiratory virus that infects the lungs and breathing passages, especially in young children.

• Transmission: Spread by respiratory droplets and contaminated surfaces (fomites).

• Prevention: Emphasizes hand hygiene and, for high-risk infants, administration of monoclonal antibodies.

• Symptoms: Cough, sneezing, fever, and wheezing; can be severe in infants and immunocompromised individuals.

• Vaccine: No approved vaccine as of now, but several candidates are in clinical trials.

Additional info: For diseases where the original table was incomplete, causative agents, transmission, and other details were inferred based on standard microbiology knowledge.