Chad hosts the highest number of refugees from Sudan, where a war erupted in April between the army and paramilitaries.
More than 8,000 people fled from Sudan to Chad in the first week of November alone, according to the United Nations refugee agency.
The country already hosts nearly 900,000, and amid escalating fighting in Sudan’s western Darfur region the influx has picked up in recent weeks.
In the Metche camp, which hosts 40,000 people, Doctors Without Borders said in a statement that the prevalence of global acute malnutrition is 13.6 percent among the under fives.
Its teams have helped around 14,000 malnourished children since the start of the year, nearly 3,000 of whom had to be taken to hospital in a serious condition, it said.
More than 10,400 people have been killed in the Sudan conflict so far, according to one estimate by the Armed Conflict Location and Event Data project.
The war has displaced more than 4.8 million people within Sudan while a further 1.2 million have fled into neighbouring countries, according to UN figures.