Monkeypox patients have turned up with what looked like mosquito bites, pimples or ingrown hairs, not the large pustules usually associated with the infection. Some did not even have visible lesions but felt excruciating pain when swallowing, urinating or emptying their bowels.

Some had headaches or depression, confusion and seizures. Others had severe eye infections or inflammation of the heart muscle. At least three of the six deaths reported so far were linked to encephalitis, an inflammation of the brain.

“We really are seeing a very, very wide range of presentation,” said Dr. Boghuma Titanji, an infectious disease physician at a clinic in Atlanta that serves people living with H.I.V…

The California patient had virus in his throat, but no respiratory symptoms, and in his rectum, but without pain or pox. The case underscores other research suggesting that the virus may be spread even by people with atypical or asymptomatic infections, said Dr. Abraar Karan, who diagnosed the patient and published a recent case report.