Respiratory Infection May be Contracted Through the Eye
A respiratory pathogen common in newborns may be passed on to the lungs following initial infection in the eye say researchers from the University of South Alabama, College of Medicine. They report their findings in the January 2007 issue of the Journal of Virology.
Respiratory syncytial virus (RSV), a common infection in children also referred to as "croup", causes common cold or flu like symptoms such as wheezing, bronchiolitis, pneumonia, and asthma and annually claims the lives of millions worldwide. Currently, there is no reliable vaccine or preventative antiviral available and post-infection treatments have proven unreliable, controversial and expensive.
In the study researchers instilled RSV in the eyes of mice and monitored the progression of infection. Results showed that RSV not only replicated robustly in the eye, but it also moved into the lung causing a respiratory disease indistinguishable from nasally acquired RSV.
"These results establish the eye as a major gateway of respiratory infection and a respiratory virus as a bona fide eye pathogen, thus offering novel intervention and treatment options" say the researchers.
(V. Bitko, A. Musiyenko, S. Barik. 2006. Viral infection of the lungs through the eye. Journal of Virology, 81. 2: 783-790)
New Method May Help Identify Bacteria that Causes Severe Dental Decay in Early Childhood
Researchers from the U.S. and abroad suggest that a new method of genetic profiling may distinguish bacterial populations that cause severe dental decay in children and be used as a basis for intervention and prevention development. They report their findings in the January 2007 issue of the Journal of Clinical Microbiology.
Severe early-childhood caries (S-ECC) is an extremely destructive form of bacterial tooth decay generally involving multiple teeth. Although previous studies have indicated Streptococcus mutans as a potential agent, researchers have yet to determine if S-ECC is caused by a single strain of bacteria or a group of bacterial species. Prior testing based on cultivation methods has proven difficult because nearly half of the bacteria in saliva and dental plaque are not cultivable.
In the study researchers collected plaque samples from twenty children, some with S-ECC and some caries-free (CF), and evaluated the difference in bacterial diversity using denaturing gradient gel electrophoresis (DGGE), a cultivation-free method which isolates total microbial genome DNA. Results showed the S-ECC group exhibited 94.5 bacterial populations while the CF group exhibited 113.4, suggesting that caries-associated bacteria become less diverse as specific groups begin to dominate the plaque biofilm.
"These results suggest that the microbial diversity and complexity of the microbial biota in dental plaque are significantly less in S-ECC children than in CF children," say the researchers. "Our study also demonstrated that PCR-based 16S rRNA gene DGGE is a sufficiently valuable tool for differentiating the microbial composition of the oral plaque in S-ECC children from that of CF children and may be further developed as a pattern recognition tool with which to identify specific group of bacteria predominantly colonized in children of various caries status."
(Y. Li, Y. Ge, D. Saxena, P.W. Caufield. 2006. Genetic profiling of the oral microbiota associated with severe early-childhood carries. Journal of Clinical Microbiology, 45. 1: 81-87.)
New Processing Method May Inactivate Norovirus in Foods
High pressure processing may inactivate human norovirus strains in foods say researchers from the U.S. They report their findings in the January 2007 issue of the journal Applied and Environmental Microbiology.
Norovirus infection is a common problem worldwide with 40% of reported cases in the U.S. alone attributed to food borne outbreaks. Shellfish and produce are two sources most frequently associated with norovirus infections due to the fact that uncooked foods can often become contaminated following exposure to contaminated irrigation waters or after human handling in the case of produce. Currently, there is no adequate intervention for contaminated shellfish because viruses can remain live for several days. Lack of suitable laboratory animals and the ability to develop the virus in vitro has hampered many prior research attempts.
A recently identified strain of murine norovirus (MNV-1) was developed in vitro and has more biochemical, pathological, and molecular similarities to human noroviruses than any previously used for research. In the study MNV-1 was evaluated for susceptibility to high pressure processing ranging from 2 to 15 minutes at temperatures between 41 and 86 degrees Fahrenheit. Results showed that a 5 minute treatment differing in pressure range was sufficient to inactivate the virus at a variety of temperatures, however, researchers found that inactivation was enhanced when applied at refrigeration temperatures. This study also demonstrated that 5 minutes of high pressure processing at 41 degrees Fahrenheit completely inactivated the MNV-1 strain in oyster tissue.
"This work is the first demonstration that norovirus can be inactivated by high pressure and suggests good prospects for inactivation of nonpropagable human norovirus strains in foods," say the researchers.
(D.H. Kingsley, D.R. Holliman, K.R. Calci, H. Chen, G.J. Flick. 2007. Inactivation of a norovirus by high-pressure processing. Applied and Environmental Microbiology, 73. 2: 581-585)