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1. Botulinum toxin has an LD 50 of 0.03 ng/kg, whereas staphylococcal enterotoxi

ID: 277515 • Letter: 1

Question

1. Botulinum toxin has an LD50 of 0.03 ng/kg, whereas staphylococcal enterotoxin has an LD50 of 1350 ng/kg. Which of these two is more toxic?

2. Consider the following information for Bacillus anthracis. For which route of entry is B. anthracis most easily able to establish an infection?

Portal of Entry

ID50 for B. anthracis

Skin

10–50 endospores

Inhalation

10,000–20,000 endospores

Ingestion

250,000–1,000,000 endospores

Portal of Entry

ID50 for B. anthracis

Skin

10–50 endospores

Inhalation

10,000–20,000 endospores

Ingestion

250,000–1,000,000 endospores

Explanation / Answer

LD50 is the amount of substance given which kills 50 percent of animals which are given this substance.

So lesser the amount of toxin substance ,the more the toxicity.

So the botulinum toxin is more toxic as the same effect will be produced by .03 ng/kg of botulinum compared to staphylococcus enterotoxin which is required 1350ng/kg.

2. As LD50 for skin entery is less ,so the toxicity will be more through this site. So there will be an infection more easily through skin. Only 10-50 endospores will do the same effect through skin compared to inhalation and ingestion which require way more number of endospores.