June 27--Yusia falls sick

• lived 10 mi outside of town

• worked as tallyman in cotton factory:

• symptoms:
• pain in the forehead
• sore throat (like a ball of fire)
• dry tongue
• tiny painful ulcers on cheeks
• muscle pains in chest, neck and small of his back
• face became sunken and drained of expression

• cared for by brother, Yasona

• Yusia's symptoms:
• cramping abdominal pain
• diarrhea
• vomiting
• prostration

July 2--Yusia's symptoms worsen

• starts to bleed profusely from nose and mouth

• diarrhea becomes bloodstained

• face looks like a skull mask

July 13--Yasona becomes sick (eventually recovers!)

July 12--Bullen, storekeeper from cotton factory becomes ill

• lived in-town

• worked at table adjacent to Yusia's

July 14--Bullen dies

• one of Bullen's two wives becomes sick; dies July 19

• worked at the cotton factory in room next to office where Yusia and Bullen had kept tallybooks and records

• bachelor with many social contacts

• lived next door to merchant, Mohammed

• played with Mohammed's assistants, Samir and Sallah, in small jazz band at local nightclub

• comforted during illness by girlfirends

• after his death, body was bathed by these women and his fiancée, Hawa

• nursed by his brother

August 18--Sallah becomes sick and dies; as does one of Mohammed's sons

August 21--Mohammed becomes sick

• leaves town and travels to hospital in provincial capital, Juba

• discharges himself and travels to Khartoum

Epidemiologists later trace 48 cases of illness and 27 deaths to contact with Paul.

August 12-22

• teacher named Mabalo Lokela toured an area near the border with the Central African Republic with small group from Yambuku mission

• diagnosed with relapse of malaria

• symptoms:
• diarrhea
• nosebleed

August 30--despite deteriorating health, man discharges himself from hospital

• is never seen again

• medical staff at Yambuku hospital advise him to go home and rest

• other patients at hospital show signs of illness, but symptoms (fever, fatique, diarrhea) are attributed to a variety of causes:
• vitamin deficiency
• post-operative recovery
• malaria

• these patients are also discharged and sent home

• symptoms:
• profuse bleeding from all orifices
• hospital staff at a loss

• his wife, Mbunzu, continues to nurse him

• Mbunzu, following tribal custom, washes her husband's body

• Mabalo's mother, Mbunzu's mother and sister, and other women friends prepare Mabalo's body for burial

• nearly all of these individuals later become sick

• Mbunzu and her sister recover

• Mabalo's mother and mother-in-law die

• others in the surrounding area become sick

• members of nursing staff at Yambuku hospital fall ill leading to widespread panic and disorder

• blood is taken to test for antibodies to typhoid bacillus

September 17--he issues first official report of the events
 

• identifies Mabalo as index case

• notes panic in the surrounding villages

• seeks assistance from Kinshasa

• microbiologist and epidemiologist plan six-day investigative study
• analyze blood samples for malaria, parasites and bacteria
• perform autopsies, preserving samples for further testing
• return to Kinshasa after only 24 hours
• bring three ailing patients with them

Early October--team of medical experts arrives in Yambuku

• place hospital under strict quarantine
• village elders in Bumba Zone advise everyone to remain at home
• all commercial and social activity in region comes to a halt

• receive news of similar outbreak in Sudan, raising fear of pan-African epidemic

The infecting agent in the Yambuku epidemic was identified as a virus, another of the filoviridae.  It was named Ebola, after the Congo's Ebola River, where it was believed to have originated.

Comparison of the viruses responsible for the disease outbreaks in Sudan and Zaire revealed them to be distinct strains of ebola virus.  Of the two, ebola Zaire was the more virulent.

In 1989, third strain was discovered during an outbreak among monkeys in a research laboratory in Reston, Virginia.  No humans became sick from their exposure to this strain although some did develop antibodies to it.

In 1995, a fourth strain was found.  Chimpanzees in the Tai Forest, Ivory Coast, died of this strain.  One researcher studying this outbreak became ill, but recovered.