Madagascar hissing cockroaches are popular pets due to their largish size, distinctive sound, and easy maintenance. The downside is that a new study shows that their bodies and feces house 14 different known allergy-causing mold species that can trigger allergies in their handlers. Some of the identified mold types can cause secondary infections if they enter open wounds or a handler's lungs.
Lead author of the study, doctoral candidate in entomology Joshua Benoit of Ohio State University doesn't want to make a judgment call on pet ownership; however he does want to drive home the point that handlers should be washing their hands when they finish playing with their pets.
Hard to Ignore
“It’s also best to maintain the cage. It’s not a pet you can ignore,” he said. “Without regular cleaning, feces will build up, and the old exoskeletons they shed will build up. And that’s where a lot of the problems happen.”
The popular critters, known in geek-speak as Gromphadorhina portentosa, manage quite well on a diet of dog food and fruit. They're prolific and don't bite. The roaches grow up to 3 inches long and one inch wide. If you squeeze them or they sense a threat, they elicit a hissing noise.
A victim of allergies himself, Benoit had the idea that the size of the insects' bodies and the fact that they live in damp areas might serve to promote mold growth. It is already known that some people are allergic to the bodies of the cockroaches that are household pests. However, the Madagascar hissing cockroaches trigger allergies from the spores that live on and around them.
Benoit and his team compared cockroaches from those infesting the hallowed halls of their institution, as well as those found in homes, pet stores, science classrooms, and zoos all over Ohio. The feces were tested first and as they had suspected, researchers found mold in the cockroaches' waste. The group then turned their eyes to the bugs themselves, looking inside and outside their bodies, in the search for moldy allergens.
Cockroaches And Their Mold
The main species of mold found on Madagascar hissing cockroaches are right up there on the CDC (Center for Disease Control and Prevention) list of common household molds such as Alternaria, Trichoderma, Mucor, Penicillium, and Rhizopus. Another mold species, Aspergillus niger, found most often in tainted food, was discovered in very large amounts in both the feces and the exoskeletons that are shed during the molting period. Unlike the unwanted roaches that make pests rather than pets out of themselves, there was almost no mold found inside the bodies of the friendly hissers.
Benoit said that the mold species found on and around the pets can produce large numbers of spores. These spores can land on the skin of a handler or be inhaled, causing allergic reactions in those sensitive to these common allergens and can bring on hay fever-like symptoms or worse. If you have symptoms, be sure to get rid of clothing, bedding, and carpet to help eliminate the spread of spores.
Not to worry, Benoit's new studies concentrate on the surprise element of his cockroach research: The mites that live in a symbiotic relationship with the roaches help to keep them clean. These mites sweep the surface of the bug and get rid of old bits of food and other debris, making mold less likely to grow.