During Turn 191 of the Tenth Interval a disease swept through the Northern and Southern Continents of Pern, decimating the population.
Nemar's Disease, named after the first victim, was a severe disease caused by a bacterium that formed heat-resistant spores, which could survive the canning process used by the Ancients. Transmission to humans was initially by consumption of the infected product then later by air and, as supplies became contaminated, water. The natural, or initial, reservoir was not known.
The initial source, although ICly unknown, was canned goods found in an Ancient cave system, which had been locked up for some 2500 Turns. The Miners found and opened the cans, being interested in their contents. When they opened the goods they found that the cans had preserved fruit, which smelled fine and even tasted fine. Later, when these same Miners died, no one was be able to pinpoint exactly the source of infection within the cave and so it was sealed. As the disease progressed, the bacterium was found in infected patients, on things that they had touched, and in the water supply.
Initially the disease was spread through ingestion via the fecal/oral route (primary). The secondary mechanism was by air via patient discharge -- coughing or sneezing that resulted in the disruption of the cellular membranes. Poor sanitation, resulting in contaminated water supplies (tertiary), further exacerbated the spread of disease.
Clinical symptoms in the primary patient group (ingestion) exhibited within 3-5 days, with severe symptoms seen in 5-7 days and death by day 7. Patients in the secondary (inhalation) group, exhibited ranges from day 1-3 post exposure onwards to around day 7. This left the question of who was infected and it was thought that perhaps the initial outbreak was a single occurrence.
Note : Times listed are for secondary infected group.
ONSET
Headache, joint and muscle aches, sore throat, and lethargy.
WITHIN 5 DAYS
Fever developed, at first low-grade (102 degrees Fahrenheit or lower) but developed into high-grade (above 103 degrees Fahrenheit) by day 7. As bacterial toxins were released into the bloodstream chills and shivering was also evident in the patient.
WITHIN 7 DAYS
This was followed by a sudden onset of diarrhea: gallons worth, which led to dehydration.
WITHIN 10 DAYS
Cardiac complications and circulatory failure (some people exhibited signs of cyanosis) slowly became evident. Patients vomited on ingestion of water or food and a raised red rash and red eyes may also have presented. Towards day 13-14 patients started bleeding, both internally and externally. Patients gradually became disorientated and confused, with bouts of violence and seizures. Pathological evidence showed that this was due to damage through hemorrhaging of the brain blood vessels, from direct infection and from the breakdown of the blood-brain barrier.
WITHIN 15 DAYS
Death.
OTHER FACTORS
In approximately 3% of the population the fever subsided at day 5-7. Patients exhibited no symptoms for upwards of a sevenday. However, at this point patients then began exhibiting disease symptoms similar to those normally seen at 10 days. Initially these patients were thought to have recovered from the disease but later they were found to be carriers of Nemar's disease, the infection responses keeping the disease in remission until it reasserted itself, having compromised both bone marrow and lymph nodes.
Incubation was 15-20 days, by which time stools were infected with bacillus. Because of high rains that Turn the water table was high and bacteria easily entered the water system. Blood was infective from 10 days past the onset of symptoms.
In the primary group, Nemar's was identified by the sudden onset of massive diarrhea.
As symptoms become more detailed, Nemar's was diagnosed by a high-grade fever and then later, with further categorization, flu-like symptoms were added to the list. From this group blood samples were studied under a microscope and small mobile rod shapes, called mobile rods, were observed and added to the diagnosis.
The primary infected groups were treated with common remedies for cold symptoms: angelica, beth root and pepper. Later, as the diarrhea developed, they were treated with mullein, meadowsweet, barberry and agrimony for the bleeding. None of these treatments were effective.
The secondary groups were treated with various combinations of the above and other herbs, until all proved ineffective. The new mold therapy, named Fleminar after the Healer who discovered it, was also tried and this too proved unsuccessful. Replacing lost fluids intravenously was tried, despite the risk of infection; this too proved to be in vain.
Infection resulted in responses ranging from life-threatening diarrhea to mild or unapparent infections with no manifestation. The reasons for these differences were unknown although prior exposure had some effect. The Healers took serum from these patients and tried to inoculate them into infected patients. These patients recovered, but there was no ability to raise enough vaccine to treat the infected population.
Healers attempt a vaccine by injecting Herdbeasts with serum from those patients who recovered from the disease. Unfortunately this failed to work and it wasn't until whole blood was inoculated from those patients displaying the full range of symptoms that they met some limited success: in all but one patient group the test failed. However, reproducing this test group they found that a vaccine raised and harvested when the animal was extremely close to death was successful, possibly due to a high titer of some substance.
Although the disease was thought wiped out there is the possibility that it remains within the soil and water, waiting for those who are susceptible to it. However, since there have been no reported cases in some Turns it is thought that some ecological pressure has resulted in demise of the bacterium.
At its height, Nemar's claimed up to 1,000 people per day. The overall mortality rate was noted at is 88%.
