Bacterial, Viral, and Foodborne Illnesses: Symptoms and Treatment
Posted on Jan 14, 2025 in Microbiology
Bacterial Infections
Borrelia burgdorferi (Lyme Disease)
- Disease: Lyme Disease
- Vector: Ticks (commonly found in deer habitats)
- Symptoms: “Bull’s-eye” rash, flu-like symptoms, heart inflammation, neurological abnormalities, arthritis
- Diagnosis: PCR DNA test, ELISA, Western Blot for IgM/IgG antibodies
- Treatment: Amoxicillin, tetracycline
- Prevention: Destroy tick habitats, use insecticides, tick repellents (e.g., DEET), inspect skin, and promptly remove ticks (within 24 hours)
Helicobacter pylori
- Characteristics: Gram-negative, non-sporulating, microaerophilic spiral bacillus; colonizes gastric mucus-secreting cells; produces urease for urea hydrolysis and ammonia release
- Diseases: Peptic ulcer disease, chronic gastritis if untreated
- Transmission: Found in family clusters or nursing homes
- Diagnosis: Gastric biopsy culture, urea breath test
- Treatment: Pepto Bismol, antibiotics
Clostridium perfringens (Gas Gangrene)
- Characteristics: Gram-positive, anaerobic, spore-forming rods; grows in wounds exposed to soil (e.g., frostbite)
- Symptoms: Severe pain, edema, drainage, muscle necrosis
- Diagnosis: Wound culture
- Treatment: Extensive surgical debridement, penicillin, hyperbaric oxygen therapy
Mycobacterium leprae (Leprosy or Hansen’s Disease)
- Characteristics: Slow-growing, acid-fast bacteria; reservoir: armadillos
- Transmission: Likely via nasal secretions; more common in children
- Treatment: Combination of antibiotics, including rifampicin
Foodborne Diseases
Campylobacter jejuni (Diarrhea)
- Characteristics: Gram-negative, slender, curved, motile rod; microaerophilic
- Symptoms: Acute bacterial gastroenteritis, fever, diarrhea, sometimes paralysis
- Transmission: Undercooked poultry, raw milk
- Infective Dose: As few as 10 viable microbes
- Treatment: Usually self-limiting
Salmonella enteritidis (Salmonella)
- Characteristics: Gram-negative, motile bacilli
- Symptoms: Acute: nausea, vomiting, abdominal cramps, diarrhea, fever, headache; Chronic: arthritic symptoms (3-4 weeks post-acute phase)
- Infective Dose: As few as 15-20 cells (varies by host health and strain)
- Mechanism: Invades gut epithelium, causing inflammation
Escherichia coli O157:H7 (Enterohemorrhagic E. coli)
- Characteristics: Produces Shiga toxin
- Symptoms: Stomach pain, bloody diarrhea, cramps
- Complications: Toxin in bloodstream, kidney clots
Clostridium botulinum (Botulism)
- Characteristics: Anaerobic, Gram-positive, spore-forming rod; found in soil
- Mechanism: Produces a toxin in anoxic foods, blocking acetylcholine release at neuromuscular junctions
- Symptoms: Difficulty breathing; high mortality rate
- Treatment: Ventilation, IV polyvalent antitoxin
- Additional Use: Botox (muscle spasms)
Listeria monocytogenes (Listeria)
- Characteristics: Gram-positive, non-spore-forming, motile at room temperature; facultatively anaerobic rod
- Sources: Soil, water, animals (e.g., poultry, cattle); deli meats, hot dogs, soft cheese, raw milk, smoked seafood, raw sprouts
- Symptoms: Fever, muscle aches, diarrhea, weakness; Pregnant women: miscarriage, stillbirth, premature delivery
- Prevention: Proper cooking and pasteurization
Vibrio cholerae (Cholera)
- Characteristics: Gram-negative, facultatively anaerobic
- Symptoms: Watery diarrhea (“rice water stool”), electrolyte loss
- Transmission: Contaminated water
- Prevention: Improved water and sanitation
- Notable Strain: Asiatic strain (e.g., Haiti cholera outbreak)
Sexually Transmitted Diseases (STDs)
Chlamydia trachomatis
- Characteristics: Gram-negative coccoid; obligate intracellular bacterium
- Diseases: Trachoma, nongonococcal urethritis (men), cervicitis (women), pelvic inflammatory disease (PID), ectopic pregnancy
- Diagnosis: Serology (antibodies)
- Treatment: Tetracycline, erythromycin
Neisseria gonorrhoeae (Gonorrhea)
- Characteristics: Gram-negative diplococcus
- Symptoms: Males: urethral discharge, painful urination; Females: vaginal discharge, risk of PID
- Diagnosis: Chocolate agar, Gram stain of exudate
Treponema pallidum (Syphilis)
- Characteristics: Gram-negative spirochete
- Symptoms: Rash (palms, soles); neurological issues (coordination problems, blindness, dementia)
- Diagnosis: Chancre slide (dark field microscopy), serology (RPR test)
- Treatment: Penicillin
Human Papillomavirus (HPV)
- Characteristics: Double-stranded DNA virus
- Diseases: Genital warts (strains 16 and 18 linked to oral cancer)
- Prevention: Vaccine, limited sexual partners
- Treatment: Cryosurgery
Genital Herpes (Herpes Simplex Virus Type 2)
- Characteristics: Double-stranded DNA virus
- Symptoms: Fever, genital soreness, fluid-filled blisters; latent in nerve cells (sacral plexus)
- Diagnosis: Genital swabs, outward lesions
- Treatment: Antivirals (Acyclovir, Valacyclovir) – no cure
Human Immunodeficiency Virus (HIV)
- Characteristics: Retrovirus with RNA genome
- Mechanism: Integrates into host DNA via reverse transcriptase
- Transmission: Blood products, sexual contact, perinatal (mother-to-fetus)
- Diagnosis: Viral isolation, reverse transcriptase assays, ELISA, immunofluorescence, Western blot, PCR
- Treatment: No cure; managed through antiretroviral therapy
- Prevention: Blood screening, education on safe practices
Chain of Infectious Disease
- Pathogen: The organism causing the disease
- Source: Where the pathogen originates
- Transmission: How it spreads to the host
- Host Susceptibility: Factors making the host vulnerable
- Exit: Pathogen’s release from the host
H5N1 Avian Influenza (Bird Flu)
- Characteristics: Highly pathogenic strain of bird flu
- Source: Waterfowl (natural carriers) transmitting to poultry
- Spread: Crowded poultry farms, long-distance poultry transport, migratory wild birds
- Risk to Humans: Rare human-to-human transmission; severe illness in individuals with weakened immune systems
- Prevention: Improve sanitation, limit exposure to infected poultry
