Ricin clinical signs

Medical personnel must consider the varying latent periods before onset of clinical signs. For patients exposed to toxins by aerosol, the latent period varies from minutes (saxitoxin, microcystin) to hours (the staphylococcal enterotoxins), even to days (ricin, the botulinum toxins). 

Variable toxicity is seen in cases of oral ingestion. Seeds that are chewed are much more likely to cause clinical signs. Seeds swallowed whole may not cause any problems at all (Kinamore et al., 1980). The amoimt of toxalbumins in the seeds will vary by size, weight, moisture content, region, season, and the period of plant growth at the time of harvesting. The ricin content of castor beans can vary from 1% to 10% (Balint, 1974). The... 

In one large clinical trial,40 low doses (18-20 pg/ m2) of intravenous ricin administered to cancer patients were well tolerated. Flulike symptoms with fatigue—in some cases very pronounced fatigue— and muscular pain were common, and sometimes nausea and vomiting occurred. The symptoms began 4 to 6 hours after administration and lasted for 1 to 2 days. Two toxic deaths were reported in Phase I clinical trails of the closely related protein toxin, abrin these patients had general seizures and other signs of central nervous system toxicity. 

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