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ScienceDaily (Mar. 18, 2008) — Their gentle nature, large size, odd sounds and low-maintenance care have made Madagascar hissing cockroaches popular educational tools and pets for years. But the giant insects also have one unfortunate characteristic: Their hard bodies and feces are home to many mold species that could be triggering allergies in the kids and adults who handle the bugs, according to a new study.

Researchers have identified 14 different types of mold on and around this species of cockroach, including several molds associated with allergies and others that can cause secondary infections if they enter the lungs or an open wound.

“This is mainly a point of public awareness,” said Joshua Benoit, lead author of the study and a doctoral candidate in entomology at Ohio State University. “We are not criticizing their use. We are just saying that if you handle these cockroaches, you should wash your hands when you’re done.

“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 natural life of the Madagascar hissing cockroach, or Gromphadorhina portentosa, is not well understood. But in captivity, the insects thrive on dog food and fruit, reproduce plentifully and do not bite. They grow to between 2 and 3 inches long and 1 inch wide, and will make their characteristic hissing sound if they are squeezed or otherwise feel threatened.

Benoit, an allergy sufferer himself, suspected the insects’ large bodies and moist living environments might combine to create a prime breeding ground for mold.

Some people are allergic to the species of cockroaches that are household pests. In those cases, the bugs’ actual bodies contain allergens. In the case of the Madagascar hissing cockroaches, the most potent mold allergens live on and around the insects instead.

Benoit and colleagues examined the insects from an Ohio State-based colony as well as those found in home collections, zoos, pet stores and science classrooms across Ohio.

The research group tested the feces first, and, as expected, found mold in the bugs’ waste. Then the team examined the giant cockroaches themselves, both outside and inside their bodies, to see what other allergens might be present.

The most commonly found mold species found on the body surfaces of young and adult Madagascar hissing cockroaches were Rhizopus, Penicillium, Mucor, Trichoderma and Alternaria, several of which are listed by the Centers for Disease Control and Prevention (CDC) as common indoor molds. Colonies of the mold species Aspergillus niger, a common contaminant of food, were particularly plentiful in the feces and external shells that had been discarded as the insects molted.

Few molds were found inside the cockroaches’ bodies.

Molds are fungi that grow best in humid conditions, and spread and reproduce by making spores. Benoit said all of the mold species found on and around the hissing cockroaches are capable of producing huge quantities of spores. And the spores themselves can get on bug handlers’ skin or be inhaled, triggering allergic responses in those sensitive to the molds.

For people who are allergic to molds, exposure can cause symptoms such as nasal stuffiness, itchy or burning eyes, wheezing or skin irritation, according to the CDC. Some people with serious allergies to molds may have more severe reactions.

Benoit now is pursuing additional studies on one surprise among the findings: Symbiotic mites also live on the cockroaches, and help keep them clean.

“The mites sweep the surface and remove old food particles and debris, so they remove places on which fungi can grow,” Benoit said.

The research is published in the March issue of the journal Mycoses. Benoit conducted the project with Jay Yoder and Brian Glenn of Wittenberg University and Lawrence Zettler of Illinois College.

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ScienceDaily (Apr. 17, 2008) — Children with mothers who have allergies or asthma have an increased risk of wheezing in the chest if they take part in baby swimming before 6 months of age. This is shown in a new study using data from the Norwegian Mother and Child Study (MoBa) at the Norwegian Institute of Public Health (NIPH).

The results come from a study of 30 000 participants from MoBa. Approximately 25 percent of these children took part in baby swimming from 0-6 months of age.

Most children who take part in baby swimming show no increased incidence of lower respiratory tract infections, ear inflammation (otitis media) or tightness and wheezing in the chest. Between 6-18 months the incidence of lower respiratory tract infections and otitis media were 13 percent and 30 percent respectively, whilst the proportion of children who experienced tightness or wheezing in the chest was 40 percent.

Among children of mothers with asthma and allergy, 44 percent of those who did not go swimming had tightness or wheezing in the chest. This was compared to the 47 percent of children who swam and experienced tightness and wheezing who had mothers with asthma and allergies.

- The difference is not large but it indicates a tendency to respiratory problems, says Wenche Nystad, primary author and Department Director at the NIPH’s Division of Epidemiology.

Earlier studies indicated that there can be a link between baby swimming and airway infections in children. It has been suggested that indoor environmental factors (airway irritants) such as volatile chlorination products for indoor swimming pools can affect lung epithelium and contribute to the development of respiratory illnesses like asthma among children.

- The connection between respiratory problems and baby swimming was suggested by a paediatrician who asked whether children with increased risk of asthma, who took part in baby swimming, had a greater tendency to develop respiratory diseases. Earlier studies indicated a connection but the results were uncertain. Therefore we want to carry out a more thorough study, says Nystad.

- If mother and baby are healthy, the study shows that there is no increased risk of otitis media or respiratory problems with baby swimming before six months of age.

Journal reference: Nystad W, Håberg SE, London S, Nafstad P, Magnus P. Baby swimming and respiratory health. Acta Paediatric. 2008; 97: 657-62.

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ScienceDaily (May 22, 2008) — A study released by researchers at the Columbia Center for Children’s Environmental Health (CCCEH) at Columbia University’s Mailman School of Public Health, shows that cat ownership may have a protective effect against the development of asthma symptoms in young children at age five. The study, published by the Journal of Allergy and Clinical Immunology, found that children with cats in the home were more likely to have made allergy-related antibodies to cats. At three years of age, children who had made antibodies to cats early in life were more likely to have wheeze, a respiratory symptom associated with asthma. However, by age five, the same children who had grown up with a cat were then found to be less likely to have wheeze.

This finding suggests that prolonged cat ownership and early life exposure to cats may have a protective effect against early asthma indicators, such as wheeze, as children reach age five. “While the study design does not allow us to recommend early cat ownership to prevent asthma, it does seem to indicate that avoidance of cats to prevent the development of asthma is not advised. However, once a child has asthma and is allergic to cats, the recommendation would still be to find a new home for the cat,” said Matthew Perzanowski, PhD, assistant professor of Environmental Health Sciences at the Mailman School of Public Health and lead author and investigator on the research.

The study is part of a broader multi-year research project started in 1998, which examines the health effects of exposure of pregnant women and babies to indoor and outdoor air pollutants, pesticides, and allergens. The Center’s prior research findings have shown that exposure to multiple environmental pollutants are associated with an increase in risk for asthma symptoms among children. For this study, the investigators controlled for other exposures that might have contributed to developmental problems such as socioeconomic factors and exposure to tobacco smoke and other environmental contaminants.

“Today’s findings contribute to a further understanding of how the environment impacts child health,” said Rachel Miller, MD, Irving Assistant Professor of Clinical Medicine at Columbia University; director, Asthma Project; associate director and lead physician scientist, DISCOVER Initiative, Mailman School’s CCCEH; and senior author on the study. “They help us comprehend the complex relationship between early exposure to cats and the risk for asthma symptoms such as wheeze. The presence of cats in the home at a very early age seems to help reduce the risk of developing asthma. This is an important finding given the high prevalence of asthma in New York City and elsewhere.”

Other investigators on the study include Frederica Perera, DrPH, Ginger Chew, ScD, Inge F. Goldstein, DrPH, Robin S. Garfinkel, PhD, Lori A. Hoepner, MPH, Adnan Divjan, Alina Johnson, and Thomas A. E. Platts-Mills, MD, PhD. The study was co-authored by researchers from the Columbia Center for Children’s Environmental Health at Columbia University’s Mailman School of Public Health and the Asthma and Allergic Diseases Center at the University of Virginia. The research was funded by the National Institutes of Health.

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ScienceDaily (July 16, 2008) — Scientists and researchers have taken a big step closer to a cure for the most common strain of avian influenza, or “bird flu,” the potential pandemic that has claimed more than 200 lives and infected nearly 400 people in 14 countries since it was identified in 2003.

Researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, in conjunction with scientists from China and Singapore, have crystallized and characterized the structure of one of the most important protein complexes of the H5N1 virus, the most common strain of bird flu.

All viruses, including H5N1, contain only a small number of proteins that govern all of the viruses’ functions. In H5N1, perhaps the most important of these proteins is RNA polymerase, which contains the instructions that allows the virus to copy itself along with all of its genetic material. The Argonne study focused on H5N1’s RNA polymerase protein, which contains three subunits: PA, PB1 and PB2.

After performing X-ray crystallography on the protein crystals at Argonne’s Structural Biology Center 19ID beamline at the Advanced Photon Source, the researchers saw a surprising resemblance in the protein structure’s image. “When we mapped out the PA subunit, it looked very much like the head of a dragon,” said Argonne biophysicist Andrzej Joachimiak. “One domain looked like the dragon’s brains, and the other looked like its mouth.”

During RNA replication — the phase during which the virus “reproduces” — all three of the subunits of the protein assemble themselves in a particular configuration. In order for this congregation to take place, the researchers determined the end of the PB1 subunit has to insert itself and bind to the “dragon’s mouth” part of the PA subunit.

This unexpected relationship between the two subunits could inspire a number of different therapies or vaccines for H5N1 that rely on muzzling the “dragon’s” jaws with another molecule or chemical compound that would block the PB1 subunit’s access to the PA site, according to Joachimiak. “If we can put a bit in the dragon’s mouth, we can slow or even potentially someday stop the spread of avian flu,” he said. “Since we are talking about a relatively small protein surface area, finding a way to inhibit RNA replication in H5N1 seems very feasible.”

Joachimiak hopes to more precisely identify the types of compounds that could inhibit RNA replication in H5N1 by looking at the atomic-level grooves and pockets within the PA “mouth” region. According to Joachimiak, scientists must gain a more thorough understanding of the geometry of that small region in order to effectively synthesize drugs that could prevent the further spread of bird flu.

Argonne researchers Joachimiak and Rongguang Zhang collaborated with Zihe Rao and Yingfang Liu, both members of the Institute of Biophysics of Chinese Academy of Sciences. Rao is one of the most influential Chinese crystallographers and biophysicists, Joachimiak said. The protein samples were manufactured in China and crystals were shipped to Argonne for data collection and structural analysis.

The work was funded by the National Natural Science Foundation of China as well as the Chinese Ministry of Science and Technology and the U.S. Department of Energy’s Office of Biological and Environmental Research.

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