Although the phenomenon of silent infections is known, scientists regard it as extremely uncommon.

Noboa is an extremely uncommon surname in the Spanish language.

Though extremely uncommon in modern times, the technique dates back to at least the 17th century.

But the police said her case was extremely uncommon.

Incidents of violent crime against foreign citizens are extremely uncommon.

It is extremely uncommon for a program to require a large percent of the address space for either of these.

It's easy to understand that fear, though in fact abduction by strangers is an extremely uncommon occurrence.

It is a member of the tryptamine family and is extremely uncommon.

These stones are extremely uncommon and usually occur as a result of a rare genetic disorder.

However, some causes are still unknown or extremely uncommon.