Table 2.

Details on outbreaks detected through data analysis (n = 10)

ID	Country, area, date of onset (references)	Aetiologic agent	Onset to detection (days)	Comments
1	Afghanistan, Kabul, May 2005 [19]	Vibrio cholerae		Increased case numbers reported through sentinel surveillance system. A low mortality was attributed to the rapid activation of the surveillance system and a rapid response.
2	Burundi, Kayanza Province, Sep 2000 [20-22]	Plasmodium falciparum	(11)	Médecins Sans Frontières (MSF) initially noticed a doubling of caseloads over the previous week and compared incidence to previous 3 years. The outbreak was not confirmed until seroprevalence tests were performed in week 7 of the epidemic.
3	Chad, Logone Occidental Province, Feb 2000 [23,24]	Neisseria meningitidis		Annual peaks of meningococcal meningitis are noted in this region.
4	Chad, Koumra district, Jan 2001 [24]	Neisseria meningitidis		No further details were available.
5	DRC, Kinshasa, Jan 2002 [25]	Measles virus		The outbreak was detected by a sentinel surveillance system. Detection was through both trend analysis and reports from health facilities not included in the system. During the outbreak there were significant delays in reporting from health districts. Limited population movement within the city delayed spread of the epidemic. Early reactive vaccination of unaffected districts could have averted many cases.
6	Sudan, Mornay village and camp, West Darfur, Jul 2004 [26-28]	Hepatatis E virus		The population of Mornay had recently increased due to the arrival of tens of thousands of internally displaced persons. Security concerns and a lack of confidence in Western medicine may have delayed detection. The local hospital became overwhelmed. Cases were reported to the EWARN system.
7	Sudan, northern Sudan, Oct 2003 [29]	Measles virus		Detection was extremely late, almost once the outbreak was over. The investigation pointed to ongoing underreporting of measles by existing surveillance systems in Sudan. Poor access to health-care facilities may be a strong contributing factor.
8	Sudan, Aweil East county (Southern Sudan), Jun 2003 [20]	Plasmodium falciparum	(7)	MSF reported an alert after quadrupling of cases. Historical comparisons were hampered by changes in diagnostic strategies and reduced health care utilisation rates due to flooding. Weekly reporting and analysis, and a free and steady supply of anti-malarials may have favoured early detection.
9	Sudan, Abou Shouk camp, North Darfur, Jun 2004 [30]	Shigella dysenteriae type 1	46	In the early stages of camp administration, there was poor reporting of diseases. An emergency meeting was held to discuss the number of diarrhoea cases being seen in therapeutic feeding centres and at camp clinics. The WHO's EWARN system verified the outbreak.
10	Sudan, Southern Sudan, Sep 2002 [31-33]	Leishmania donovani		Recently internally displaced populations had poor access to health care. Cases were carried on stretchers for days to receive treatment.

* Investigation revealed previously undetected or undiagnosed outbreaks; () indicates that dates were estimated.