"We moved the vaccines from Khartoum to El Geneina [the capital of West Darfur] on Monday and expect to start the vaccinations in two to three days," Gouido Sabatinelli, WHO Representative in Sudan, told IRIN on Tuesday.
"The next few days will be critical," Sonja Nieuwenhuis, senior health manager in West Darfur for the Swiss-based humanitarian organisation Medair, said in a statement.
"We have trained staff, and we will work closely together with the Ministry of Health, WHO and UNICEF [UN Children's Fund] to vaccinate nearly 20,000 people," Nieuwenhuis added. "But we need to move fast, to stop this outbreak spreading further," she said.
Abu Seroj is situated in the Kulbus locality of West Darfur State and the vaccination exercise would be extended to areas surrounding the camp.
WHO said in statement released on Friday that laboratory tests had confirmed two cases of the disease to be of the "Neisseria Meningitides W 135" type.
Meningitis is an infection of the meninges, the thin lining that surrounds the brain and the spinal cord and is caused by viruses and bacteria that are often found in airborne dust.
Overcrowded housing situations and large population displacements due to crisis, pilgrimages and regional markets facilitate the transmission of Neisseria Meningitides.
WHO said it had been closely monitoring the occurrence of the disease in the region, following reports of three separate confirmed cases in Riyad, Adamata and Abu Seroj IDP camps in West Darfur in the first week of May.
"According to the Sudanese Federal Ministry of Health' Standard Operating Procedures, one laboratory confirmed meningitis case raises the alert flag in any IDP camp. Two laboratory confirmed cases in one week in one camp makes an outbreak," Sacha Bootsma, WHO communications officer in Khartoum, told IRIN.
Medair had been providing health-care for people in the area since 2001, and started supporting the clinic in Abu Seroj in May 2004. In recent weeks, the clinic staff in Abu Seroj reported an alarming increase in cases of suspected meningitis.
The population of Abu Seroj, a little village in a remote part of West Darfur, had swelled by nearly 50 percent to 5,000 people in recent months, Medair reported. People driven from their homes by ongoing conflict had gathered in Kuma Camp on the outskirts of the town.
Meanwhile, in North Darfur State, 10 suspected cases of meningitis were reported during the week of 8-14 May, with no laboratory confirmed cases.
In the week from April 30 to May 6, 13 suspected cases of meningococcal meningitis including, one death were reported in IDP camps in Greater Darfur. According to the latest WHO update on meningitis, a total of 132 cases of suspected meningococcal meningitis had been reported in IDP camps across Darfur since 1 January 2005, resulting in nine deaths.
Meningitis is related to dry weather, occurring between December and June. Because of dust winds and upper respiratory tract infections due to cold nights, the local immunity diminishes, increasing the risk of meningitis.
Earlier this year, cases of Neisseria Meningitidis had been reported in the eastern Sudanese states of Gadaref and Blue Nile, bordering Ethiopia. Between 22 January and 2 February, a total of 169 cases including 23 deaths, were reported from both states.