Readers weigh in on coronavirus, cats and more

Coronavirus questions

Lessons from outbreaks of coronaviruses that cause SARS and MERS may help scientists get a handle on the ongoing outbreak of a novel coronavirus, Tina Hesman Saey reported in “How the new coronavirus stacks up against SARS and MERS” (SN: 2/15/20, p. 6).

Reader Inge Revuelta wondered about scientists’ calculations of how infectious the new coronavirus is — its R₀. “I would like to know if this estimated number has any real practicality considering that the community of experts in this field has failed to reach a consensus on its accuracy,” Revuelta wrote.

The R₀ can vary over time as people in a population become immune to the virus, or as public health measures are put in place, Saey says. “The number has practical implications. It helps public health officials anticipate how big an outbreak might be and plan responses. It also indicates whether public health measures are working,” she says. Travel restrictions in Wuhan, China, seemed to reduce the virus’ spread, decreasing the R₀, according to a study posted online February 18 at medRxiv.org.

Reader Diana Lutz wondered if the new coronavirus could become seasonal like the flu. “Are MERS and SARS seasonal?” she asked.

Like influenza and common cold viruses, the new virus could stick around infecting people if control efforts fail, but it is unknown if the virus will become seasonal (SN Online: 3/4/20). Severe acute respiratory syndrome, or SARS, is not seasonal and has not caused an epidemic since the initial outbreak in 2002. Middle East respiratory syndrome, or MERS, does not seem to reliably be seasonal, at least not the way influenza is, Saey says. “Camels may carry the MERS virus year-round, but some researchers have detected a peak in infections about six months after the winter calving season,” she says. “That’s typically when young camels catch MERS and may be more likely to pass it to people later on.” More MERS cases in people occur April through July, studies have shown, but people may catch the virus at other times of year.

Feline fascination

New research may reduce house cats’ allergen levels or make people less reactive to their feline friends, Erika Engelhaupt reported in “With a litter of tactics, scientists work to tame cat allergies” (SN: 2/15/20, p. 16).

Reader Mark Friedman wondered if there was an at-home test available to measure a cat’s allergen levels. “How hard could it be to create a chemical card test that could be touched with cat saliva?” Friedman asked.

Such a home test kit doesn’t appear to exist, Engelhaupt says. When she wanted to get her cat’s allergen levels tested, the only option she could find was to send hair samples to Indoor B­iotechnologies, a company that does consumer testing for a fee.

Martin Chapman, founder of Indoor Biotechnologies, says that the c­ompany about 15 years ago experimented with a rapid test for the feline protein that triggers allergies in people. But the test, which analyzed dust and could analyze hair and saliva samples, showed n­egative results at high allergen concentrations. “Not good,” Chapman says.

A saliva-based test is an interesting idea and could have a market, E­ngelhaupt says, especially as new allergen treatments come out; cat owners may want to monitor their cats’ levels.

Speeding space rock 

Asteroid 2020 AV2 is the first found orbiting closer to the sun than Venus, C­hristopher Crockett reported in “For the first time, an asteroid has been found nearer to the sun than Venus” (SN: 2/15/20, p. 5).

Reader A­ntonia Musgrave asked how fast 2020 AV2 travels.

The asteroid has a range of speeds, from roughly 126,000 k­ilometers per hour to 170,000 km/h, C­rockett says. That’s because its orbit — from just inside Venus’ orbit to Mercury’s orbit and back — is elliptical. “The asteroid speeds up as it gets closer to Mercury’s orbit, and then slows down as it goes out to Venus’ orbit,” he says. For comparison, Earth orbits the sun at about 108,000 km/h.