New Study Suggests Antiviral Protein May Inhibit Ebola and Marburg Virus
Researchers from Germany found that an antiviral protein previously shown to inhibit other viruses may also protect against Ebola and Marburg virus infection. They report their findings in the March 2007 issue of the Journal of Virology.
Ebola virus (EBOV) and Marburg virus (MARV) belong to the Filoviridae family and cause severe hemorrhagic fever in humans and nonhuman primates. Filovirus infections are characterized by high fever, hemorrhages and shock and are responsible for mortality rates up to 90%. Currently, there is no vaccine or therapy available for treating infected patients.
In a previous study researchers found the zinc finger antiviral protein (ZAP) capable of inhibiting Moloney murine leukemia virus and Sindbis virus replication. In this study ZAP was tested for its antiviral activity in cells infected with EBOV and MARV. Results showed significant inhibition of EBOV, up to 95 % while MARV was less significant suggesting the antiviral effectiveness of ZAP may depend on the filovirus species.
“In conclusion, the data demonstrate that ZAP exhibits antiviral activity against filoviruses, presumably by decreasing the level of viral mRNA,” say the researchers.
S. Muller, P. Moller, M.J. Bick, S. Wurr, S. Becker, S. Gunther, B.M. Kummerer. 2006. Inhibition of filovirus replication by the zinc finger antiviral protein. Journal of Virology, 81. 5: 2391-2400.)
Probiotic Treatment Reduces Salmonella Infection in Pigs
Researchers from Ireland found that treatment with probiotic bacteria reduced Salmonella infection in pigs and may have potential human applications. They report their findings in the March 2007 issue of the journal Applied and Environmental Microbiology.
Salmonella spp. is one of the major causes of food-borne gastroenteritis worldwide, with an estimated 160,000 cases reported annually in the European Union alone. Probiotics, described as live microorganisms believed to promote a health benefit in the host when administered in controlled amounts, have emerged in recent years as an alternative method to counteract bacterial infections. Previous studies have focused largely on the lactic acid bacteria (LAB) group and many have shown beneficial effects in small animal models challenged with gastrointestinal infection.
In the study pigs were divided into two groups, one of which received milk containing five LAB probiotic strains and the other, serving as a control group, received regular milk for 30 days. Following 6 days of treatment the pigs were then challenged orally with Samonella enterica serovar Typhimurium after which their health and feces were monitored for 23 days. The pigs receiving probiotic treatment showed reduced incidence, severity, and duration of diarrhea as well as significantly lower numbers of Salmonella in fecal samples 15 days postinfection.
“The administered probiotic bacteria improved both the clinical and microbiological outcome of Salmonella infection,” say the researchers. “These strains offer significant benefit for use in the food industry and may have potential in human applications.”
(P.G. Casey, G.E. Gardiner, G. Casey, B. Bradshaw, P.G. Lawlor, P.B. Lynch, F.C. Leonard, C. Stanton, R.P. Ross, G.F. Fitzgerald, C. Hill. 2007. A five-strain probiotic combination reduces pathogen shedding and alleviates disease signs in pigs challenged with Salmonella enterica serovar Typhimurium. Applied and Environmental Microbiology, 73. 6: 1858-1863.)
Protein Found in Chickens May Help Protect Against Food-Borne Pathogens
Researchers from The Netherlands have identified a protein in the digestive tract of chickens that may serve as an antimicrobial agent against food-borne pathogens. They report their findings in the March 2007 issue of the journal Antimicrobial Agents and Chemotherapy.
Food-borne pathogens, responsible for most cases of food poisoning in developed countries, are commonly affiliated with poultry products including chicken. Therapeutic doses of antibiotics in chicken feed have been administered since the 1950’s, but are now discouraged due to increasing rates of antibiotic resistance.
In the study researchers tested for B-defensin gallinacin-6 (Gal-6) protein expression in chickens and explored antimicrobial activity against gram-positive and gram-negative bacteria as well as yeast. Researchers observed high expression of Gal-6 in the esophagus and crop and moderate expression in the glandular stomach. Colony-counting tests showed strong bactericidal activity against Campylobacter jejuni, Salmonella enterica serovar Typhimurium, Clostridium perfringens, and Escherichia coli, all major food-borne pathogens. Fungicidal activity was also noted. In a kill-curve study results showed treatment with Gal-6 reduced C. perfringens survival within sixty minutes.
“In conclusion, to our knowledge, this is the first report of a chicken B-defensin highly expressed in the digestive tract and displaying strong bactericidal activity against food-borne pathogens.” say the researchers.
(A. van Dijk, E.J.A. Veldhuizen, S.I.C. Kalkhove, J.L.M. Tjeerdsma-van Bokhoven, R.A. Romijn, H.P. Haagsman. 2006. The B-defensin gallinacin-6 is expressed in the chicken digestive tract and has antimicrobial activity against food-borne pathogens. Antimicrobial Agents and Chemotherapy, 51. 3: 912-922.)