( UPDATED October 29, 2014 ) Ebola virus infection is spreading into more counties and territories in West Africa, according to a report published online October 28 in the Morbidity and Mortality Weekly Report.

As of October 19, a total of 9911 cases have been reported from three heavily affected West African countries (Guinea, Liberia, and Sierra Leone), according to the World Health Organization's latest numbers, released October 22. Liberia (4665 cases) reported the highest case counts, followed by Sierra Leone (3706) and Guinea (1540).

In the current report, researchers at the Centers for Disease Control and Prevention (CDC) assembled data from situation reports from the Guinea Interministerial Committee for Response Against the Ebola Virus and the World Health Organization, the Liberia Ministry of Health and Social Welfare, and the Sierra Leone Ministry of Health and Sanitation. The data reflect "all reported suspected, probable, and confirmed cases as defined by each country." The CDC notes that reported cases are only a portion of all actual cases because not all cases are reported and reporting delays are different in each country.

The geographic distribution of Ebola virus infection has broadened since August 31 to September 23. At that time, counts of Ebola cases were highest in areas where the three countries meet.

During September 28 to October 18, case counts "were highest in the area around Monrovia and in the district of Bong, Liberia; the Freetown area and the northwest districts of Sierra Leone; and the district of Macenta, Guinea."

As of October 18, the Ebola cumulative incidence map shows that the highest incidence rate (>100 cases per 100,000 population) was reported by the districts of Guéckédou and Macenta in Guinea; the districts of Bomi, Bong, Lofa, Margibi, and Montserrado in Liberia; and the districts of Bombali, Kailahun, Kenema, and Port Loko in Sierra Leone.

The CDC is working with ministries of health and other organizations to control and halt the ongoing Ebola virus disease outbreak in West Africa. The latest updates on the outbreak, including case counts, can be found on the CDC website. The most current clinical guidelines on the outbreak are also available on the website.

Morb Mortal Wkly Rep. Published online October 28, 2014. Full text