The health ministry said it and the World Health Organization (WHO) had confirmed that a three-and-a-half-year-old Somali girl who developed paralysis of her legs at the camp in northeastern Kenya had contracted wild polio.
"Investigations have confirmed this to be a case of poliomyletis," it said, adding it was the first known case in Kenya since 1984 and that a probe was underway to determine whether it was contracted in the country or imported.
Dr James Nyikal, the director of medical services at the ministry, stressed in a statement that the girl had been isolated and that "the situation is under control."
The appearance of polio in Kenya, which had eradicated the disease 22 years ago, heightened concerns about a recent influx to tens of thousands of Somali refugees crossing the border due to security fears and drought.
In a separate statement sent to a global medical clearinghouse, the ministry said the child's mother had told health officials her daughter had been born at one of the three camps that make up the sprawling Dadaab refugee complex.
It also said the mother claimed her daughter had been vaccinated for polio at the camp as part of a routine vaccination drive and had never visited Somalia, where at least 31 cases of the disease have been confirmed this year.
"The ministry is trying to confirm whether this is an imported case of polio or was acquired in Kenya," it said. "If it was acquired in Kenya, it would be the first reported indigenous case in Kenya since 1984."
The alarming discovery came as Somalis continue to stream across the border into Kenya fearing unrest as tensions rise between the country's powerful Islamist movement and weak government.
The ministry said tests by labs in Kenya and South Africa found the girl to be infected with a polio strain matched to one isolated to Somalia's Lower Juba region, the capital of which, Kismayo, was seized by the Islamists last month.
Since Kismayo was taken from a local militia allied to the government, the number of Somalis crossing into Kenya has soared from an estimated 300 to 400 per day to close to 1,000, according to the UN refugee agency.
More than 30,000 Somalis have fled their home country since the beginning of the year, severely straining resources at Dadaab, about 470 kilometers (290 miles) northeast of Nairobi, now home to more than 157,000 refugees.
In April, the United Nations said some 200 children had been infected by polio in Somalia since July 2005 when the disease reappeared after three years in the lawless nation, home to about 10 million people, raising fears that polio would spread across the region, better known for its substandard health infrastructure.
WHO polio experts say efforts to tackle polio in the Horn of Africa region have been complicated by ongoing instability, exacerbated by recurrent drought and floods in Somalia and heavy rains in Ethiopia.
Polio remains endemic in just four countries in the world, the hotbed being Nigeria, followed by India, Afghanistan, and Pakistan.
Beyond the Horn of Africa, imported cases of the virus have been confirmed in Namibia, Bangladesh, Niger, Democratic Republic of Congo, Indonesia, Yemen, Nepal and Angola.
The disease, which once crippled thousands of children every year in industrialized countries, was brought under control by rich nations thanks to new vaccines in the late 1950s and early 1960s.
Attempts to beat it in the developing world kicked off in the 1970s, and the international community launched a major drive in 1988 to try to wipe out the disease.
Source: AFP, Oct. 17, 2006