Blackblood

The corpse of the bull was strangely shrunken, with its skin stretched between jutting ribs. The ranger tilted her head; this bull had been here for two days, yet there were no flies or insects on the corpse. The farmer kept his distance from the bull, with a rag tied tightly around his face.
"As soon as I saw him die I knew there was a problem. Healthy one day and the next leaned against the fence like this? Orren across the way said blackblood was working its way through the Southwend, but I had hoped it wasn't true." The farmer gave a glance at his other cattle, fenced away from the corpse. "If word gets out about this, I'll have to burn all of them."
"No, that won't be necessary." Kyris shook her head. "Isolate each cattle in its own pen and space them apart so they can't come in contact with each other. After a week you'll discover which are blackblooded and which are alright. The Covenant confirmed that after six days if the cattlehead hasn't died they are free of the disease." She pulled an old knife from her belt and stepped forward. "If this is alright...?"
"Yes, go ahead, though I hate to see a girl like you take this risk. Could I offer a headscarf, at least?" The farmer pulled a red checkerboard bandana from his back pocket.
"Thanks." Kyris tied it around her face. The latest knowledge of blackblood indicated it did not transmit to people well through miasma, but she figured it would make the farmer feel better.
The bull had died upright, leaning against a post, which made the next step a bit easier. The ranger slid the knife through the papery-thin skin of the bull's neck, and quickly poured an unguent over the embedded blade. She withdrew it carefully, as the knife was now covered in a slick black liquid that beaded on the metal and dripped into the dirt.
She sighed and pushed the knife back into the wound, as it could no longer be used. Kyris stepped back and called to the farmer. "This one's got blackblood of the first order. Bring the wood and animal tallows and I'll help you burn the body."

Transmission & Vectors

Blackblood is a disease of cattle, incidentally transmissible to people. Between cattle, the strongest suspicion lies on miasma, as cattle in very close proximity for extended periods will transmit blackblood to each other, and dead cattle can infect living cows and bulls. While people can very rarely contract blackblood from a live infected cow, ingesting the meat of an infected cow is a guaranteed way to contract blackblood. No instances of people being infected from other sickened people are known.

Causes

The cause of blackblood is unknown; all that is known about its cause is that healthy cattle will be sickened if put in contact with a diseased or dead animal, leading to speculation about poisoned miasma.

Symptoms

In cattle, blackblood is a rapid-onset disease. The cattle will be alright for a few days, lethargic the next day, and dead the day after, with no other externally visible symptoms. Cutting open the animal indicates the extent of the disease's internal damage - what flows through the veins of infected cattle is a runny black liquid, entirely unlike ordinary blood. This liquid is quite dangerous to handle but can be spilled onto the earth safely.
In people, infection by blackblood is agony - as the disease progresses, the body essentially begins to die slowly, starting from the limbs and working towards the core of the body, with the toes and fingers wasting away before the hands and feet wither and die. The pain is excruciating, leading to many blackblood victims to ask to be euthanized as a mercy.

Treatment

No treatment for blackblood is known, though it is now subject to intensive research to see if magecraft can prove of any benefit. Those who contract blackblood are typically given painkilling barbituates as a soporific, but this has no effect on the course of the disease itself.

Prognosis

Blackblood is an incredibly lethal disease, with all people and nearly all cattle infected by it dead within the week. There are three recorded instances of cattle surviving a blackblood infection, but this is subject to significant controversy, as the only for-sure way to diagnose blackblood is through bloodletting, and it is unclear if those cattle had bled black.

Prevention

Cattle must be isolated from each other to halt the spread of blackblood. Though close contact is not essential for blackblood to spread (experiments at The Covenant indicate it can be spread between cattle at some short distance), it is the most efficient method of transmission. After a week without a blackblood death, a herd of cattle can be considered disease-free, though some farmers take the secondary option of culling the whole herd. Traditionally, blackblood-infected corpses are incinerated at high temperatures as soon as possible, as a lingering corpse remains infectious.
Ordinary people are unlikely to get infected by blackblood except by consuming tainted meat, and the fear of blackblood has resulted in abattoirs enforcing a policy of holding cattle for seven days until slaughter. Any cases of blackblood in the herd of cattle awaiting slaughter will result in a mass culling.

Epidemiology

Most cattle are left to graze and roam freely on open fields and pastures, with cattle owned by different farmers intermingling. This allows blackblood to rapidly spread through an area's cattle herds. If a farmer unknowingly slaughters an infected animal for meat, a local blackblood outbreak in the population is assured. 
Proposals have been made for keeping cattle herds partitioned away from each other in order to limit the spread of any given outbreak, but this comes up against several old laws and traditions with regard to common ownership of pastures and shared grazing rights, and is considered unrealistic.

History

Prior to the Principality of Etoile, blackblood outbreaks were terrifying, and the report of a single dead animal could result in a massive cull of cattle for miles around and the ruination of many small tenant farmers and serfs under Skapetry Serfdom. If it became known that a tavern had served blackblood-infected beef, the building would usually end up being burned to the ground.
The control of blackblood and the safety of beef consumption is considered one of the hallmarks of the Progress as espoused by the Principality, as the state sanctioning of abattoirs and rigorous procedure regarding cattle slaughter has made blackblood infection in humans exceedingly rare. Every case of human blackblood infection has been the result of a small farmer slaughtering an infected cow on their own, as opposed to sending it to an abattoir for processing and packaging. While blackblood still is endemic in the cattle population, it is considered a plague that can be managed, if not wholly eliminated.

Cultural Reception

As blackblood infection is one of the more unpleasant ways to die, infected beef is often times the murder weapon in various sundry plays and shows at the Grand Amphitheatre of Etoile as well as in half-florin magazines. No known case of assassination-by-blackblood has been recorded, as handling the infected beef is as dangerous to the assassin as it is to the victim.

Origin

Natural

Cycle

Short-term

Rarity

Rare