So far, thankfully, the monkeypox outbreak isn't following in the footsteps of the coronavirus pandemic. In fact, new cases are even on the decline in the U.S. Still, companies' products to detect or treat this virus are much needed.

The availability of such products may help slow or even stop the outbreak in its early stages. SIGA Technologies (SIGA -3.29%) today offers a treatment, and Quest Diagnostics (DGX -0.84%) sells a diagnostic test. Which of these companies makes a better monkeypox investment today? Motley Fool contributors Adria Cimino and Keith Speights present the case for each.

A smallpox and monkeypox specialist

Adria Cimino (SIGA): SIGA's business is smallpox, monkeypox, and all other orthopox viruses. The company sells one product at the moment. It's called TPOXX and treats these sorts of viruses. Back in 2018, the U.S. government offered SIGA a contract worth as much as $600 million if all options are exercised. This covers the management of a TPOXX stockpile for the U.S.

Most recently, SIGA announced the exercise of a $26 million option to provide intravenous formulations of the drug to the U.S. SIGA also has received orders from governments around the world. The company won about $60 million in international orders for oral doses of TPOXX since the start of the year.

As a result, SIGA's shares have soared 76% this year. However, SIGA's weakness is that TPOXX is the company's only product. But the company's strength is this could be a very important product. The world eradicated smallpox about 40 years ago. But samples kept for research purposes mean the risk isn't completely over. It's important for countries to stockpile protection against this deadly illness.

The emergence of monkeypox has increased awareness of the potential threats of this family of viruses. Today, SIGA has developed relationships -- and signed contracts -- with governments. It's easy to imagine these governments regularly ordering TPOXX to protect their populations.

That could translate into more revenue for SIGA down the road. And in the near term, any new increase in monkeypox cases could drive investors to buy SIGA shares.

More than monkeypox

Keith Speights (Quest Diagnostics): No one can question Quest Diagnostics' credentials when it comes to monkeypox. On Sept. 7, the company became the first to win U.S. Emergency Use Authorization (EUA) for a lab-developed monkeypox diagnostic test. While the Centers for Disease Control and Prevention (CDC) recently warned that some monkeypox tests could fail to detect infection, Quest's test wasn't in the group.

To be sure, Quest isn't likely to become the next monkeypox meme stock. Shares of the diagnostics information services company have fallen nearly 30% year to date despite its EUA victory. However, for investors hoping to profit over the long term, Quest is worthy of consideration. 

Monkeypox probably won't be as serious of a global issue for too much longer. Fortunately, Quest has a lot more going for it than just an opportunity in diagnosing this one virus. The company ranks as the leader in the big, fragmented diagnostics market and continues to pick up market share. Quest expects to increase its adjusted earnings per share by 7% to 9% over the next couple of years. It also offers a dividend that currently yields nearly 2.1%.

Some stocks receiving attention with the spread of the monkeypox virus are like the hare in Aesop's famous fable, while Quest is similar to the tortoise. But we all know which animal ultimately won the race.

SIGA or Quest?

If the threat of monkeypox increases, SIGA shares could climb higher. If that doesn't happen, SIGA still may have a path to more revenue in the future -- but share gains may not be as certain. SIGA shares remain risky. Quest, due to its broader portfolio, offers a stronger opportunity for share performance over the long term.