The injured man was taken to hospital but was not reported to be seriously hurt.
The second man, 23, was taken to a central London police station for questioning, police said on Friday.
Local police officers in protective clothing were sent to the house, in the Forest Gate area of the capital, while nearby roads were cordoned off.
Police said the operation was "intelligence-led" and followed liaison between security services and the Health Protection Agency, which guards against infectious diseases.
A police spokeswoman said: "It is a big operation. At this stage there is nothing to suggest members of the public in the immediate area are at risk.
"At this stage there is nothing to suggest members of the public in the immediate area are at risk"
British police spokeswoman
"If we believe there is a potential risk, appropriate action will be taken and advice issued," she added.
Britain remains on high alert after the July 7 suicide bombings last year, in which 52 people died and hundreds were wounded.
A report in May this year found that two of the four bombers, all British, were known to security officers but the threat they posed was not realised.