A staffer for Sen. Tom Carper's (D) office in Delaware has become the latest congressional staffer to test positive for the novel coronavirus.

Carper's office said in a statement that the individual is not severely ill and has been placed under self-quarantine. Aides added that the staffer, who was not identified, has not traveled to Washington, D.C. and had "no contact with Senator Caper or other members of Congress since exhibiting symptoms."

Carper's office also said that other members of his staff who came into contact with the aide while she was exhibiting symptoms will be "self-isolating themselves at home for the next 14 days and monitoring their symptoms closely" out of caution.

"If any of those staff members start showing symptoms of COVID-19, they will be tested as well," the office added.

Last week, Sen. Maria Cantwell's (D-Wash.) Washington, D.C., office confirmed the first known instance of a congressional staffer contracting the virus. And days later, Rep. David Schweikert (R-Ariz.) revealed on Sunday that a member of his D.C.-based team had also tested positive.

In recent weeks, states and municipalities across the country have reported mass school closures as officials have worked to the prevent the spread of the coronavirus, for which a vaccine has not yet been found, according to the Centers for Disease Control and Prevention (CDC).

So far, 46 states and Washington, D.C. have reported confirmed and presumptive positive cases of the virus to the CDC.

According to the health agency, the virus is thought to be spread by people within close contact of each other, or about 6 feet, and through "respiratory droplets produced when an infected person coughs or sneezes."

The CDC also states on its web site that "reported illnesses have ranged from mild symptoms to severe illness and death for confirmed coronavirus disease 2019 (COVID-19) cases." Symptoms of the virus - which can include fever, cough and shortness of breath - can appear anywhere between 2 days to two weeks after a person is exposed to the virus.

According to data from the Johns Hopkins Center for Systems Science and Engineering, more than 169,000 cases of the virus have been reported worldwide. More than 6,500 deaths have been reported amid the outbreak, as well as 77,200 recoveries.