Eukaryotic diseases of the digestive nervous system and lymph unit 10

Eukaryotic Diseases Overview

• Focus: Digestive, Circulatory, Lymphatic, and Nervous Systems

• Relevant Learning Objectives: USLO10.3 and 10.4

Eukaryotic Infectious Diseases of the Digestive System

• Fungal

  • Candida albicans

    • Cause of oral thrush and vaginal infections

• Protozoal

  • Cryptosporidium hominis

  • Giardia lamblia

  • Entamoeba histolytica

  • Balantidium coli

• Helminths

  • Enterobius vermicularis (pinworm)

  • Taenia (tapeworm)

  • Trichinella spiralis

Fungal Infections of the Digestive System

• Candida albicans

  • Dimorphic fungi, part of normal flora in urogenital tract

  • Causes: Candidiasis (vaginal thrush/oral thrush)

  • Triggered by antibiotics leading to overgrowth

  • Common in immunocompromised individuals (especially HIV phase 2 and 3)

  • Virulence Factors:

    • Adhesins (for attachment)

    • Biofilm formation

    • Proteases and phospholipases

  • Treatment: antifungal rinses

Protozoal Infections of the Digestive System

• Cryptosporidium hominis

  • Reservoir: mammals, primarily in contaminated water

  • Symptoms: watery diarrhea, nausea, dehydration, fever

  • Diagnosed by stool sample; treated with rehydration and antiprotozoal medications

• Giardia lamblia

  • Found in freshwater; can be asymptomatic

  • Symptoms can include watery diarrhea, abdominal pain

  • Antigenic variation allows for chronic infections; vehicle usually contaminated water

  • Diagnosis via stool sample; treated with rehydration and antiprotozoal medications

• Entamoeba histolytica

  • Reservoir: freshwater environments; causes dysentery and severe diarrhea

  • Virulence: enzymes to destroy phagocytes; low infectious dose (ID50)

  • Diagnosed through stool samples; treated with antiprotozoal drugs

• Balantidium coli

  • Commonly asymptomatic but can lead to diarrhea and abdominal pain

  • Major reservoir: pigs; diagnosed via stool sample

  • Treatment involves antiprotozoal agents and rehydration

Helminthic Infections of the Digestive System

• Enterobius vermicularis (Pinworm)

  • Common in children; often asymptomatic but can cause perianal itching

  • Lifecycle involves nocturnal laying of eggs; diagnosed via tape test

  • Treatment includes anti-helminthic medications; wash bedding thoroughly

• Taenia species (Tapeworms)

  • Flatworms; can cause mild gastrointestinal symptoms or severe issues if larvae invade muscles

  • Reservoir: undercooked meats; diagnosed through stool samples

  • Treatment involves anti-helminthic drugs

• Trichinella spiralis

  • Often found in pork; symptoms range from asymptomatic to gastrointestinal distress

  • Larvae infect intestines and muscles, causing flu-like symptoms

  • Diagnosed through serological tests and muscle biopsy; treated with anti-helminthics

Eukaryotic Diseases of the Circulatory and Lymphatic Systems

• Protozoal

  • Plasmodium species (Malaria)

    • Transmitted by Anopheles mosquitoes; symptoms include fever, chills, and organ failure

    • Diagnosed via blood smears; treatment with anti-malarial drugs

  • Toxoplasma gondii

    • Reservoirs: cats and other mammals; can cause severe issues in pregnant women

    • Treatment necessary for at-risk individuals; resolves in immunocompetent patients

  • Trypanosoma cruzi (Chagas disease)

    • Transmitted via the kissing bug; symptoms range from fever to chronic digestive and cardiac issues

    • Diagnosed through blood smears; treated with antiprotozoal drugs

  • Leishmania species

    • Transmitted by sand flies; causes skin sores and systemic infections

    • Diagnosed from tissue specimens; treatment focused on serious cases

  • Babesia

    • Transmitted by ticks; has similar symptoms to malaria

    • Diagnosed via blood smears; treated with antiprotozoal treatments

• Helminthic Infections

  • Filariasis (Elephantitis)

    • Lymphatic disease common in tropical areas; caused by Wuchereria worm

    • Symptoms involve lymphedema and swelling; diagnosed by elevated eosinophils

Eukaryotic Diseases of the Nervous System

• Protozoal

  • Acanthamoeba

    • Rare but severe infection (keratitis, encephalitis); diagnosed based on symptoms and exposure

    • Treatment is difficult, especially in advanced cases

• Toxoplasma gondii

  • Can lead to neurotoxoplasmosis in immunocompromised; contact with cats or feces is a risk factor

• Trypanosoma brucei (African sleeping sickness)

  • Symptoms include cyclical fever and neurological deterioration; transmission via tsetse flies

  • Treated with antiprotozoal drugs; follow-up treatment necessary

Algal Diseases of the Nervous System

• Dinoflagellates

  • Cause paralytic shellfish poisoning during blooms; neurotoxin is the main virulence factor

  • Treatment involves respiratory support in severe cases

Important Note

• Many eukaryotic infections involve complex life cycles and varying symptoms; diagnosis often requires stool or blood samples and treatment outcomes vary.