Insight - Nigeria races to halt Ebola spread in overcrowded Lagos

Nigerian custom officers wearing face masks and gloves screen passengers arriving at Nnamdi Azikiwe International Airport in Abuja August 11, 2014. REUTERS/Afolabi Sotunde

LAGOS (Reuters) - When Liberian-American Patrick Sawyer collapsed at Lagos airport, he brought Ebola into a potentially ideal place for the deadly virus to spread - a vast, dirty, overcrowded city where tracing carriers and their contacts is a major problem.

Sawyer's arrival last month from Liberia - which along with Sierra Leone and Guinea lies at the centre of an outbreak that has killed more than 1,000 people - caught authorities in the Nigerian commercial capital unprepared.