Toxicities 8 – Parasites

Each of these parasites has unique characteristics and life cycles, leading to a variety of symptoms and disease manifestations in humans. Proper diagnosis and treatment are essential to manage and prevent complications from these parasitic infections. Symptoms can often flare up and then subside, lying dormant, only to flare up again when your immune system is low.

1. **Amebiasis (caused by Entamoeba histolytica)**:
  - **Description**: A protozoan parasite that primarily affects the intestines.
  - **Symptoms**: Ranges from asymptomatic to severe dysentery with bloody stools, abdominal pain, and fever. Can lead to liver abscesses, presenting with right upper quadrant pain, fever, and hepatomegaly. In rare cases, it can spread to the lungs, brain, or skin.

2. **Entamoeba hartmanni**:
  - **Description**: A non-pathogenic amoeba similar in morphology to E. histolytica but smaller.
  - **Symptoms**: Generally considered non-pathogenic, it does not cause disease. However, its presence can sometimes indicate poor sanitation and possible co-infection with pathogenic species.

3. **Entamoeba dispar**:
  - **Description**: Morphologically identical to E. histolytica but non-pathogenic.
  - **Symptoms**: Typically asymptomatic. It does not invade tissues or cause disease.

4. **Entamoeba coli**:
  - **Description**: A non-pathogenic amoeba found in the intestine.
  - **Symptoms**: Non-pathogenic and generally asymptomatic. Its presence indicates fecal-oral contamination.

5. **Endolimax nana**:
  - **Description**: A non-pathogenic intestinal amoeba.
  - **Symptoms**: Usually asymptomatic, but occasionally associated with mild gastrointestinal disturbances such as diarrhea.

6. **Elephantiasis (Lymphatic Filariasis)**:
  - **Description**: Caused by filarial worms (Wuchereria bancrofti, Brugia malayi, Brugia timori) transmitted by mosquito bites.
  - **Symptoms**: Chronic lymphatic obstruction leading to severe swelling and thickening of the skin and underlying tissues, especially in the legs, arms, breasts, and genitalia. Acute symptoms include fever and lymphangitis.

7. **Echinococcosis (Hydatid Disease)**:
  - **Description**: Caused by tapeworms of the genus Echinococcus, primarily E. granulosus and E. multilocularis.
  - **Symptoms**: Formation of cysts in the liver, lungs, and other organs. Symptoms depend on the cyst location and size: abdominal pain, chest pain, cough, and allergic reactions or anaphylaxis if cysts rupture.

8. **Dracunculiasis (Guinea Worm Disease)**:
  - **Description**: Caused by the nematode Dracunculus medinensis.
  - **Symptoms**: After ingestion of contaminated water, larvae migrate and mature. About a year later, a painful blister forms on the skin, often on the lower limbs, through which the worm emerges, causing intense pain and secondary infections.

9. **Dirofilariasis**:
  - **Description**: Caused by Dirofilaria spp., typically affecting the pulmonary arteries.
  - **Symptoms**: Subcutaneous nodules or pulmonary nodules which may be detected incidentally on X-rays. Symptoms can include localized pain and swelling or respiratory symptoms such as cough and chest pain if the lungs are involved.

10. **Dipylidium caninum (Dog Tapeworm)**:
  - **Description**: A tapeworm that commonly infects dogs and cats, transmitted to humans through ingesting infected fleas.
  - **Symptoms**: Usually mild gastrointestinal symptoms, pruritus ani (itchy anus), and sometimes the presence of proglottids (tapeworm segments) in the stool or around the anus.

11. **Diphyllobothriasis (Fish Tapeworm)**:
  - **Description**: Caused by Diphyllobothrium latum, acquired by eating undercooked or raw fish.
  - **Symptoms**: Abdominal discomfort, diarrhea, vomiting, and weight loss. Chronic infection can lead to vitamin B12 deficiency and subsequent anemia.

12. **Dientamoeba fragilis**:
  - **Description**: A flagellate protozoan that infects the human intestine.
  - **Symptoms**: Diarrhea, abdominal pain, weight loss, and fatigue. Some people may be asymptomatic.

13. **Cystoisospora belli**:
  - **Description**: A coccidian parasite causing intestinal infection.
  - **Symptoms**: Watery diarrhea, abdominal pain, fever, and weight loss. Severe and chronic in immunocompromised individuals.

14. **Cysticercosis (caused by Taenia solium larvae)**:
  - **Description**: Occurs when humans ingest eggs of the pork tapeworm, which develop into larvae (cysticerci) in tissues.
  - **Symptoms**: Muscle pain, subcutaneous nodules, and neurological symptoms if larvae lodge in the brain (neurocysticercosis), including seizures, headaches, and hydrocephalus.

15. **Cyclosporiasis**:
  - **Description**: Caused by the protozoan Cyclospora cayetanensis.
  - **Symptoms**: Watery diarrhea, loss of appetite, weight loss, stomach cramps, bloating, increased gas, nausea, and fatigue. Symptoms can last for weeks if untreated.

16. **Cryptosporidiosis (caused by Cryptosporidium spp.)**:
  - **Description**: A protozoan parasite that infects the intestines.
  - **Symptoms**: Watery diarrhea, stomach cramps, dehydration, nausea, vomiting, fever, and weight loss. Can be severe and prolonged in immunocompromised individuals.

17. **Crabs (Pubic Lice - Pthirus pubis)**:
  - **Description**: An ectoparasite infesting the pubic hair and other coarse body hair.
  - **Symptoms**: Intense itching in the genital area, visible lice and nits on pubic hair, and sometimes secondary bacterial infections from scratching.

18. **Entamoeba histolytica**:
  - **Description**: A pathogenic amoeba causing amebiasis.
  - **Symptoms**: Mild to severe diarrhea, stomach pain, cramping, and fever. Can cause dysentery with blood and mucus in the stool and extraintestinal manifestations such as liver abscesses.

19. **Angiostrongyliasis**:
  - **Description**: Caused by Angiostrongylus cantonensis (rat lungworm) or A. costaricensis.
  - **Symptoms**: Eosinophilic meningitis with severe headache, stiff neck, and neurological symptoms (A. cantonensis). Abdominal angiostrongyliasis causing severe abdominal pain (A. costaricensis).

20. **Anisakiasis**:
  - **Description**: Caused by ingesting larvae of Anisakis spp. from raw or undercooked fish.
  - **Symptoms**: Severe abdominal pain, nausea, vomiting, and allergic reactions. Symptoms mimic acute appendicitis or Crohn's disease.

21. **Ascariasis (caused by Ascaris lumbricoides)**:
  - **Description**: A large intestinal roundworm.
  - **Symptoms**: Often asymptomatic, but heavy infections cause abdominal pain, intestinal blockage, growth impairment in children, and respiratory symptoms during larval migration (Löffler's syndrome).

22. **Babesiosis**:
  - **Description**: A tick-borne disease caused by Babesia parasites.
  - **Symptoms**: Fever, chills, sweats, headache, body aches, loss of appetite, nausea, fatigue, and hemolytic anemia. Severe cases may cause organ failure and death, especially in immunocompromised individuals.

23. **Balantidiasis (caused by Balantidium coli)**:
  - **Description**: A ciliate protozoan causing intestinal infection.
  - **Symptoms**: Persistent diarrhea, abdominal pain, nausea, vomiting, and sometimes severe dysentery. Complications include perforation of the colon leading to peritonitis.

24. **Balamuthia mandrillaris**:
  - **Description**: A free-living amoeba causing granulomatous amebic encephalitis (GAE).
  - **Symptoms**: Headaches, fever, stiff neck, vomiting, neurological deficits (seizures, partial paralysis), and often fatal.

25. **Acanthamoeba**:
  - **Description**: A free-living amoeba causing Acanthamoeba keratitis and granulomatous amebic encephalitis (GAE).
  - **Symptoms**: Acanthamoeba keratitis: Eye pain, redness, blurred vision, light sensitivity, excessive tearing. GAE: Headaches, fever, neurological deficits, and often fatal.

26. **Baylisascaris (caused by Baylisascaris procyonis)**:
  - **Description**: A roundworm from raccoons.
  - **Symptoms**: Severe neurological symptoms including eosinophilic meningoencephalitis, ocular, and visceral larva migrans. Can cause severe damage or death due to larval migration through organs.

27. **Blastocystis hominis**:
  - **Description**: A protozoan parasite with uncertain pathogenicity.
  - **Symptoms**: Diarrhea, abdominal pain, bloating, excessive gas, and sometimes asymptomatic. The clinical significance is still debated.

28. **Capillariasis (caused by Capillaria spp.)**:
  - **Description**: Nematode infection, particularly Capillaria philippinensis and Capillaria hepatica

.
  - **Symptoms**: Intestinal capillariasis: Severe malabsorption, diarrhea, weight loss, abdominal pain. Hepatic capillariasis: Hepatomegaly, abdominal pain, eosinophilia.

29. **Cercarial Dermatitis (Swimmer’s Itch)**:
  - **Description**: Caused by skin penetration of cercariae of non-human schistosomes.
  - **Symptoms**: Itchy rash, small reddish pimples, blisters, or pustules, developing soon after swimming in infested waters. Self-limiting.

30. **Chagas Disease (caused by Trypanosoma cruzi)**:
  - **Description**: A protozoan parasite transmitted by triatomine bugs.
  - **Symptoms**: Acute phase: Fever, malaise, swelling at the infection site (chagoma). Chronic phase: Cardiac complications (cardiomyopathy, heart failure), digestive issues (megacolon, megaesophagus), and neurological symptoms.

31. **Chilomastix mesnili**:
  - **Description**: A non-pathogenic flagellate protozoan.
  - **Symptoms**: Generally asymptomatic. It is considered a commensal organism and does not cause disease.

32. **Clonorchiasis (caused by Clonorchis sinensis)**:
  - **Description**: A liver fluke acquired by eating undercooked freshwater fish.
  - **Symptoms**: Often asymptomatic, but chronic infection causes bile duct inflammation, obstruction, recurrent cholangitis, pancreatitis, and an increased risk of cholangiocarcinoma (bile duct cancer).

33. **Bed Bugs (Cimex lectularius and Cimex hemipterus)**:
  - **Description**: Blood-feeding insects that infest human dwellings.
  - **Symptoms**: Itchy, red bite marks usually in a line or cluster. Secondary infections can result from scratching. Psychological effects include anxiety, insomnia, and allergic reactions.

34. **Cutaneous Larva Migrans (CLM)**:
  - **Description**: Caused by hookworm larvae (Ancylostoma spp.) penetrating the skin.
  - **Symptoms**: Itchy, winding rash that migrates as larvae move under the skin, commonly known as "creeping eruption."

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35. **Entamoeba polecki**:  - **Description**: An amoeba found in pigs and primates, occasionally infecting humans.  - **Symptoms**: Usually asymptomatic or mild gastrointestinal symptoms. It is less pathogenic compared to E. histolytica.

 

36. **Fasciolopsiasis (caused by Fasciolopsis buski)**:  - **Description**: A large intestinal fluke acquired by ingesting contaminated water plants.  - **Symptoms**: Abdominal pain, diarrhea, malnutrition, and in severe cases, intestinal obstruction. Chronic infection can cause edema and ascites.