What's causing the "Grisis Signis?"
A new outbreak of widespread "madness", known as "Grisis Signis" among native Central American tribes, is affecting native Miskito communities on the northern Caribbean Nicaraguan coast, and health authorities have not offered any scientific explanation for this phenomenon.
The information, published today by "El Nuevo Diario" newspaper, indicates that this region of the country is also suffering famine caused by a plague of rats that devoured crops. It adds that at least 31 native persons in the northern Caribbean coast had been affected by "Grisis Signis", which provokes attacks of violence and hysteria.
Saul Miranda, head of the health center in Waspam, the main municipality on the Coco River at the Honduras border, told the newspaper that 21 cases were detected in the Raiti community, 729 km northeast of Managua. He added that 4 additional cases were detected in the community of Santa Fe, while in Krin Krin village, indigenous leaders reported 6 ill persons.
The illness causes seizures and hallucinations, affecting only Miskito natives, who interpret the affliction as the result of a curse or sorcery. Those affected become quite strong, attacking households and becoming violent when somebody tries to disarm them. Some walk around the villages armed with sticks and machetes, sometimes returning to their homes after having been absent for some days. The only way in which affected persons return to normal is by taking herbs given to them by a traditional healer ("curandero"), but after the episode they do not remember anything at all.
Duing other outbreaks [a similar outbreak was reported in October 2003], Health Ministry authorities have not offered any scientific explanation for this illness.
Meanwhile, Coco River communities have been suffering for many months from famine caused by a plague of rats, which devoured their crops, and they have also been affected by floods caused by the recent tropical storms and hurricanes. Government authorities, with support from the World Food Program (WFA), have brought food and support for these communities that have been historically affected by natural disasters.
Comments on the email mention that there are a number of infectious agents that have been previously noted to cause psychosis in sufferers, including brucellosis, leptospirosis, and even Lyme disease. Other possibilitites mentioned include mycotoxicosis, due to a fungal toxin that can cause hallucinations that has been implicated in the Salem witch trials. Non-infectious causes, such as vitamin deficiencies, may also play a role.
I don't know how closely this outbreak is being examined, but I wonder if they're checking the rats for other parasites as well, in addition to the agents mentioned above. For those of you who haven't read Carl Zimmer's Parasite Rex yet, you're missing out on a fascinating exposition of all kinds of ways that parasites make their hosts do crazy things--"attacks of violence and hysteria" seem mild compared to causing animals to become sterile and raise parasite progeny as their own "young," for example; or causing a grasshopper to commit suicide.
This outbreak also allows me to mention another one of my pet interests, as I've noted before: infectious causes of chronic illness. It's long been known that infectious agents can mess with our minds: rabies was associated clinically with hydrophobia before the agent was ever isolated; similarly with the neurological effects of Treponema pallidum, the causative agent of syphillis. Are we seeing a new microbe here? A new clinical manifestation of an old one? Simple vitamin deficiency? I don't know, but I hope someone in the area is finding out.