The phrase "are thought to kill" is correct and usable in written English.
It can be used when discussing beliefs or assumptions about the lethal effects of something, often in a scientific or medical context.
Example: "Certain bacteria are thought to kill healthy cells, leading to severe illness."
Alternatives: "are believed to cause death" or "are considered lethal."
Cytotoxins are thought to kill cells in the target organ.
After all, hippos, despite their docile appearance, are thought to kill more people in Africa than any other large animal.
The 7.4 million pet cats in the UK are not a scourge, Bradshaw said, echoing the view put forward by the Royal Society for the Protection of Birds, which advises that while pet cats are thought to kill around 55m birds a year,, they tend to prey on the sick or weak.
Antimicrobial peptides are thought to kill bacteria by breaking their cell membranes, although the exact mechanisms are still unclear (Sato and Feix 2006; Mani et al. 2005).
Cytotoxic lymphocytes are thought to kill target cells by means of potent cytotoxic granules that congregate near the microtubular organizing center and the Golgi apparatus at one pole of the killer cell.
Puff adders like this one are thought to kill more people than any other venomous snake in Africa.
One adult in five may be infected with HIV, and AIDS is thought to kill nearly 500 people every day.
Strenuous exercise was thought to kill by exhausting healthy hearts, and competitive sports were out of step with flower power.
At the moment, it is thought to kill around 2.7m people a year, 1m of them children.
Doctors have called for an urgent international effort to combat a "pandemic of bad drugs" that is thought to kill hundreds of thousands of people globally every year.
In the developing world, preeclampsia is one of the leading causes of maternal death; it is thought to kill more than seventy-five thousand womeachach year.
