As of today (21 November), Mali has officially reported a cumulative total of 6 cases of Ebola virus disease, with 6 deaths. Of the 6 cases, 5 are laboratory confirmed and one remains probable as no samples were available for testing.
These numbers include the 2-year-old girl who initially imported the virus into Mali and died of the disease on 24 October.
Intensive tracing and monitoring of the child’s numerous contacts, including many who were monitored in hospital, failed to detect any additional cases. All 118 contacts, including family members, have now passed through the 21-day incubation period without developing symptoms.
The virus was almost certainly re-introduced into Mali by a 70-year-old Grand Imam from Guinea, who was admitted to Bamako’s Pasteur Clinic on 25 October and died on 27 October. He has been reclassified as a Guinea case, as he developed symptoms in that country. No samples were available for testing.
Pasteur Clinic: direct and indirect links
All 5 cases in this new outbreak are linked, 4 directly and 1 indirectly, to the patient in the Pasteur Clinic.
The first was a 25-year-old male nurse who worked at the clinic and was assigned to care for the Imam. He was hospitalized on 8 November. His case was laboratory-confirmed on 11 November and he died the same day.
The second case was confirmed in a doctor who worked at the clinic and treated the Imam. He developed symptoms on 5 November and was hospitalized on 8 November. Laboratory confirmation was received on 12 November. He died on 20 November.
The remaining 3 cases occurred in a family. The Imam visited this family when he arrived in Bamako on 25 October, prior to his admission at the Pasteur Clinic. The 51-year-old father subsequently visited the Imam at the clinic.
The father developed symptoms on 7 November and died on 10 November from an undiagnosed cause.
His 57-year-old wife developed symptoms on 29 October. She was admitted to another clinic on 11 November and then transferred to a hospital on 12 November. She died that same day.
The third case is the son. He visited yet another clinic on 5 November, was not admitted, and died at home on 14 November. Ebola infection was laboratory-confirmed in the wife and the son.
Stepped up contact tracing
A massive effort is currently under way to identify all potential chains of transmission, monitor contacts, and prevent the outbreak from growing larger. At present 327 contacts have been identified and 310 (95%) of these have been placed under daily surveillance.
This rigorous “detective” work shows that the deceased nurse from the Pasteur Clinic had the largest number of contacts, at 98, including 75 family members.
As the successful experiences in Senegal and Nigeria show, aggressive contact tracing, which seeks to find and break every chain of transmission immediately after an imported case, can hold the number of additional cases to very small numbers and support a rapid end to the outbreak.
The Ministry of Health, with assistance from the WHO country office, has augmented the number of staff engaged in contact tracing by drawing on polio surveillance teams and using local medical students with training in epidemiology.
In addition, WHO has deployed 10 epidemiologists through its Global Outbreak Alert and Response Network, or GOARN.
The country is also ramping up its capacity to perform exit screening at the Bamako airport.
Guinea: Many mourners attended the funeral
The Imam was buried in his native village of Kourémalé, Guinea, on 28 October. That event has now been investigated. Thousands of mourners may have attended the funeral. Some of them touched the body as part of the traditional funeral ceremony. About 300 contacts are being traced.
Experts in Mali and at WHO agree that Mali will remain at risk of further imported cases as long as transmission across the border is ongoing.
UPDATED: This situation assessment was updated on 21 November to include new information received overnight, including improvements in contact tracing, the death of the sole surviving patient and more details about the last 3 cases in the transmission chain.