Organophosphate poisoning
Organophosphate poisoning is poisoning due to organophosphates (OPs). Organophosphates are used as insecticides, medications, and nerve agents. Symptoms include increased saliva and tear production, diarrhea, vomiting, small pupils, sweating, muscle tremors, and confusion. While onset of symptoms is often within minutes to hours, some symptoms can take weeks to appear. Symptoms can last for days to weeks.
Organophosphate poisoning occurs most commonly as a suicide attempt in farming areas of the developing world and less commonly by accident. Exposure can be from drinking, breathing in the vapors, or skin exposure. The underlying mechanism involves the inhibition of acetylcholinesterase (AChE), leading to the buildup of acetylcholine (ACh) in the body. Diagnosis is typically based on the symptoms and can be confirmed by measuring butyrylcholinesterase activity in the blood. Carbamate poisoning can present similarly.
Prevention includes banning very toxic types of organophosphates. Among those who work with pesticides the use of protective clothing and showering before going home is also useful. In those who have organophosphate poisoning the primary treatments are atropine, oximes such as pralidoxime, and diazepam. General measures such as oxygen and intravenous fluids are also recommended. Attempts to decontaminate the stomach, with activated charcoal or other means, has not been shown to be useful. While there is a theoretical risk of health care workers taking care of a poisoned person becoming poisoned themselves, the degree of risk appears to be very small.
OPs are one of the most common causes of poisoning worldwide. There are nearly 3 million poisonings per year resulting in two hundred thousand deaths. Around 15% of people who are poisoned die as a result. Organophosphate poisoning has been reported at least since 1962.
Toxicology of red imported fire ant venom
In the United States, more than 40 million people live in areas infested with fire ant populations and 14 million people are stung by them annually. A quarter of all victims stung by red imported fire ants are expected to develop sensitivity to the venom, and approximately 6,000 will suffer anaphylaxis. 51% of people who relocated themselves to infested areas report getting stung within three weeks after arrival. In a survey conducted in South Carolina, 33,000 people (or 94 per 10,000 population) received medical attention due to red imported fire ants, and 660 people (1.9 per 10 000 population) were treated for anaphylaxis. In Texas, 79% of participants in a survey stated they had been stung by red imported fire ants, while 20% had not. 61% of West Texans state they had been stung by the ants before, compared to 90% in central Texas, 89% in east Texas, 86% in the gulf coastal regions, 78% in the south and 72% in the north. In separate survey, 87% of individuals classed their reactions as mild, 12% as moderate and 1% as severe. In Australia, 64,000 homes are within red imported fire ant infested areas, and 140,000 consultations and 3,000 anaphylactic reaction cases are predicted every year by 2030 if government efforts to eradicate the ant fail. A survey conducted in China shows that one-third of participants in infested areas were victims of red imported fire ant stings.