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Questions and Answers
What is the primary effect of the tetanus toxin on inhibitory neurons?
What is the primary effect of the tetanus toxin on inhibitory neurons?
Which of the following is a clinical presentation of tetanus?
Which of the following is a clinical presentation of tetanus?
What ultimately leads to respiratory failure in tetanus patients?
What ultimately leads to respiratory failure in tetanus patients?
What neurotransmitter is continuously released, causing muscle contraction in tetanus?
What neurotransmitter is continuously released, causing muscle contraction in tetanus?
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The spastic paralysis seen in tetanus is primarily due to a lack of which type of signals?
The spastic paralysis seen in tetanus is primarily due to a lack of which type of signals?
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The backward arching position seen in tetanus patients is known as what?
The backward arching position seen in tetanus patients is known as what?
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What initial muscle group is most affected in the early stages of tetanus?
What initial muscle group is most affected in the early stages of tetanus?
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Prolonged muscle spasms in tetanus primarily involve which types of muscles?
Prolonged muscle spasms in tetanus primarily involve which types of muscles?
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Which microorganism is responsible for causing Amebic Dysentery?
Which microorganism is responsible for causing Amebic Dysentery?
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Cutaneous Leishmaniasis is primarily transmitted by which of the following vectors?
Cutaneous Leishmaniasis is primarily transmitted by which of the following vectors?
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What is the primary method of transmission for Chagas Disease?
What is the primary method of transmission for Chagas Disease?
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Which of the following best describes the pathogenesis mechanism of Clostridium tetani?
Which of the following best describes the pathogenesis mechanism of Clostridium tetani?
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What is a significant clinical presentation associated with infection by Clostridium botulinum?
What is a significant clinical presentation associated with infection by Clostridium botulinum?
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In preventing infection from Clostridium botulinum, which food preservation method is most effective?
In preventing infection from Clostridium botulinum, which food preservation method is most effective?
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Which statement best describes the transmission of neonatal tetanus caused by Clostridium tetani?
Which statement best describes the transmission of neonatal tetanus caused by Clostridium tetani?
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Which of the following is a potential outcome of botulism if not treated promptly?
Which of the following is a potential outcome of botulism if not treated promptly?
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What is the infective stage of Entamoeba histolytica?
What is the infective stage of Entamoeba histolytica?
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What is the primary clinical manifestation of amoebic dysentery?
What is the primary clinical manifestation of amoebic dysentery?
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Which demographic is more commonly affected by amoebic liver abscess?
Which demographic is more commonly affected by amoebic liver abscess?
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How do trophozoites of E. histolytica contribute to the pathogenesis of amoebic dysentery?
How do trophozoites of E. histolytica contribute to the pathogenesis of amoebic dysentery?
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What type of transmission is associated with Entamoeba histolytica?
What type of transmission is associated with Entamoeba histolytica?
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Which condition is caused by Leishmania mexicana?
Which condition is caused by Leishmania mexicana?
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What type of organism is Leishmania mexicana?
What type of organism is Leishmania mexicana?
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What is one of the complications of severe tetanus treatment?
What is one of the complications of severe tetanus treatment?
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Study Notes
Infectious Diseases
-
Clostridium botulinum - Botulism:
- Gram-positive, large, blunt-ended rods that produce endospores.
- Most species are motile obligate anaerobes.
- Found in soil and aquatic sediments; its spores contaminate vegetables, meat, and fish.
- Causes botulism (food poisoning) and floppy baby syndrome.
- Colonizes the large intestine, producing exotoxin slowly absorbed.
- Inhibits acetylcholine release at neuromuscular junctions, causing flaccid paralysis, vomiting, and diarrhea.
- Symptoms include lethargy and poor muscle tone; death can occur due to respiratory paralysis.
- Treatment: Horse anti-serum (antitoxin) administered as soon as possible.
- Prevention: Proper food preservation techniques to prevent clostridial exotoxin production; avoid swollen or dented canned food, especially homemade.
Clostridium tetani & Tetanus
- Pathogen: Clostridium tetani, a common soil bacterium.
- Morphology: Vegetative cells are gram-positive rod-shaped.
- Infectious agents: Spores infecting puncture wounds, severe burns, or postsurgical incisions; fecal contamination of umbilical cord (neonatal tetanus).
- Mechanism: C. tetani exotoxin (tetanospasmin) binds irreversibly to neurons, blocking neurotransmitter release at inhibitory synapses.
- Action: Tetanus toxin travels retrograde from the peripheral nervous system to the central nervous system.
- Mechanism Cont.: Prevents presynaptic release of inhibitory neurotransmitters glycine and GABA.
- Outcome: Causes severe, prolonged muscle spasms (spastic paralysis).
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Clinical presentations:
- Early stages affect jaw muscles (trismus or lockjaw), preventing mouth opening.
- Other voluntary muscles gradually become involved.
- Death often results from chest muscle paralysis, leading to respiratory failure.
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Clinical presentation (Cont):
- Patients have prolonged muscle spasms of both flexor and extensor muscles.
- Spastic muscle contractions, difficulty opening the jaw (trismus), characterized by a smile ("risus sardonicus"), and back muscle contractions with backward arching (Opisthotonos position).
- Patients are extremely irritable and susceptible to seizures.
Entamoeba histolytica - Amoebic dysentery
- Defining pathogenic species: Entamoeba histolytica.
- Stages: Immotile, highly resistant cysts and trophozoites (actively feeding and reproductive stages).
- Pathogenesis (Read): Trophozoites invade large intestinal walls, multiply in submucosa and form flask-shaped ulcers, ingesting blood cells from damaged capillaries.
- Subsequent complications: Amoebic liver abscess can form when trophozoites are carried to the liver via portal circulation, forming abscesses typically in the right lobe in adults and more often in males.
- Transmission: Fecal-oral route (alimentary).
- Infective stage: Mature cysts.
- Localisation: Large intestine.
- Pathogenesis (Cont): Ingested cysts form trophozoites in the small intestines, moving to the colon, infecting normal intestinal flora, resulting in ulcers in the intestinal wall leading to acute or chronic diarrhea, including blood and mucus in stools.
- Extra-intestinal amoebiasis: Abscesses in the liver, lungs, brain, or skin.
Leishmania Mexicana - Cutaneous leishmaniasis
- Pathogen: Leishmania mexicana, Leishmania tropica, and Leishmania braziliensis.
- Classification: Subphylum Mastigophora (flagellates).
- Disease: Cutaneous leishmaniasis (local).
- Geographic distribution: Central and South America, Africa, and parts of Asia and Europe.
- In Belize: Found in northern and southern Belize, especially in densely forested areas where loggers, soldiers, and forestry department personnel reside.
- Transmission: Sand fly vector ( Phlebotomus or Lutzomyia genera).
- Hosts: Humans, dogs, and wild rodents.
- Localisation: Cells of the skin.
- Further notes: Promastigotes (with flagellum) develop in the intestine of the sand fly.
Trypanosoma cruzi – Chagas disease
- Pathogen: Trypanosoma cruzi.
- Disease: American trypanosomiasis, or Chagas disease.
- Geographical distribution: South and Central America.
- Vector: Infected bug species of the family Triatomidae (Reduviid bugs, nocturnal).
- Other transmission modes: Congenital transmission or blood transfusion.
- Reservoir hosts: Armadillos, opossums, rodents, monkeys, dogs, and cats.
- Localisation: Blood (acute phase), cells of lymph nodes, spleen, liver, brain, and muscles.
- Acute presentation: (usually asymptomatic), but may present with fever, rash, headache, lymphadenopathy, and edema of the brain (Romaña sign-swollen eyes).
- Chronic presentation: Alternating periods of fever and apparent recovery, followed by depression, lethargy, potentially leading to heart (cardiomegaly, dilated cardiomyopathy) and/or esophagus complications.
- Diagnosis: Serological methods to detect the presence of antibodies; xenodiagnosis using "clean" laboratory-bred triatomine bugs.
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Description
Explore the crucial aspects of two significant infectious diseases caused by Clostridium botulinum and Clostridium tetani. Understand their characteristics, symptoms, treatment options, and prevention methods. Test your knowledge on how these pathogens affect health and safety.
