Around 1% of dracunculiasis cases result in death from secondary infections of the wound.When dracunculiasis was widespread, it would often affect entire villages at once. Outbreaks occurring during planting and harvesting seasons severely impair a communitys agricultural operations – earning dracunculiasis the moniker "empty granary disease" in some places. Communities affected by dracunculiasis also see reduced school attendance as children of affected parents must take over farm or household duties, and affected children may be physically prevented from walking to school for weeks.Infection does not create immunity, so people can repeatedly experience dracunculiasis throughout their lives. Prevention
There is no vaccine for dracunculiasis, and once infected with D. medinensis there is no way to prevent the disease from running its full course. Consequently, nearly all effort to reduce the burden of dracunculiasis focuses on preventing the transmission of D. medinensis from person to person. This is primarily accomplished by filtering drinking water to physically remove copepods. Nylon filters, finely woven cloth, or specialized filter straws are all effective means of copepod removal. Sources of drinking water can be treated with the larvicide temephos, which kills copepods. Where possible, open sources of drinking water are replaced by deep wells that can serve as new sources of clean water. Public education campaigns inform people in affected areas how dracunculiasis spreads and encourage those with the disease to avoid soaking their wounds in bodies of water that are used for drinking. Epidemiology
Dracunculiasis is nearly eradicated, with just 15 cases reported worldwide in 2021.
Methacholine (INN, USAN) (trade name Provocholine), also known as Acetyl-β-methylcholine, is a synthetic choline ester that acts as a non-selective muscarinic receptor agonist in the parasympathetic nervous system. Medical uses
Methacholine is primarily used to diagnose bronchial hyperreactivity, which is the hallmark of asthma and also occurs in chronic obstructive pulmonary disease. This is accomplished through the bronchial challenge test, or methacholine challenge, in which a subject inhales aerosolized methacholine, leading to bronchoconstriction. Other therapeutic uses are limited by its adverse cardiovascular effects, such as bradycardia and hypotension, which arise from its function as a cholinomimetic. Pharmacology
It is highly active at all of the muscarinic receptors, but has little effect on the nicotinic receptors. Methacholine has a charged quaternary amine structure, rendering it insoluble to lipid cell membranes. Clinically, this means that it will not cross the blood–brain barrier and has poor absorption from the gastrointestinal tract. It is broken down at a relatively slow rate within the body, due to its relative resistance to acetylcholinesterases. The chemical structure of methacholine is identical to acetylcholine but with a methyl group on the beta carbon (hence being called acetyl-β-methylcholine), this β-methyl group provides selectivity towards muscarinic receptors as compared to nicotinic receptors. The quaternary ammonium group is essential for activity. The ester makes it susceptible to the enzyme acetylcholine esterase. Contraindications
Use of methacholine is contraindicated in patients with recent heart attack or stroke, uncontrolled hypertension, known severe airway disease, or an aortic aneurysm.