H5N1 influenza virus is changing
A new strain of the H5N1 avian influenza virus has appeared and has become dominant in southern China, reported the November issue of the Proceedings of the National Academy of Sciences of the USA.
The new virus belongs to the previously uncharacterized Fujian-like sublineage, which first appeared in late 2005. It is dominant in a large area of southern China currently and has been transmitted to Hong Kong, Laos, Thailand and Malaysia. According to the study authors, poultry vaccination against the ‘old’ H5N1 sublineage might have played a role in selecting in favor of this new influenza virus.
Influenza viruses usually have a high rate of mutations and the existence or emergence of a new H5N1 variant is unsurprising. However, precautions must be taken in vaccination programs to ensure the viral antigens in vaccines are not ‘out-of-date’ and can still give protection against the new influenza virus strains.
“Commitment is needed from all governments to implement prevention and control programs, such as surveillance of virus circulation,” said Bernard Vallat, Director of the World Organization for Animal Health (OIE). The predominance of the new H5N1 virus in parts of Asia has emphasized the importance of surveillance and postvaccination monitoring in addition to vaccination campaigns, which are crucial in containing avian influenza.
Source: Smith GJD, Fan XH, Wang J et al. Emergence and predominance of an H5N1 influenza variant in China. Proc. Natl Acad. Sci. USA 103(45), 16936–16941 (2006).
The Food and Agriculture Organization of the United Nations (www.fao.org).
New drug for ear infection enters Korea
OctoPlus N.V. (The Netherlands) has given Green Cross Corp. (Republic of Korea) exclusive rights to develop and commercialize OP-145, a new drug for chronic otitis media, for the Korean market. However, OctoPlus will keep the manufacturing rights and will provide bulk materials to its new partner.
Chronis otitis media is a persistent inflammation of the middle ear that may follow an acute bacterial infection, which is very common in young children. Sulfa-based antibiotics, penicillins and cephalosporins are the treatment of choice for otitis media. Surgery is required, however, in cases of antibiotic nonresponders.
OP-145 is a synthetic peptide that neutralizes bacterial toxins that cause ear inflammation. It is under Phase II clinical trials currently and also shows promise in the treatment of other inflammations, such as sinusitis and chronic bronchitis. Phase III trials will be carried out in Korea where the drug will be marketed.
Source: OctoPlus N.V., The Netherlands (www.octoplus.nl).
Ebola pattern emerges
Scientists have published data recently from a decade-long study that implicates climate as an influencing factor in the spread of the Ebola hemorrhagic virus. They have also established an association between Ebola virus in humans and the wildlife population.
Sally Lahm, a visiting biologist at the University of California (San Diego, USA) and colleagues in Africa and the UK tracked the disease in Gabon and adjacent Northwest Republic of the Congo (Africa). They recorded outbreaks of the disease in animals and human exposure to these animals. They discovered that there was a pattern in the spread of the disease and it, therefore, was not as erratic as first thought.
Lahm explained that “some researchers have hypothesized that outbreaks of Ebola are randomly spaced periodic outbursts, while others have suggested that Ebola has spread like a wave surging over the central African landscape, our results are intermediate between these two views”. She continued “there is a perceived pattern to the way the virus spreads, but it is not simply a wave affecting everything in its path, since apparently healthy mammal communities thrived in close proximity to Ebola epidemic sites”.
Lahm was conducting ecological studies in Makoku, Gabon, when she noted several outbreaks in humans of the Ebola virus. This initiated her research into how it affected the surrounding animal populations. She began recording data based on reports from villagers, hunters, fishers and miners in relation to animal illness and deaths. From this, she discovered that there were 397 dead animals in the surrounding forests. This was unusually high considering the decomposition rate and the vast number of scavenging animals and insects in surrounding areas. The animals found dead included gorillas, chimpanzees, bush pigs, mandrills, antelope and porcupines. Although 14 of Lahm’s samples from these animals failed to detect Ebola, sightings of ill animals at 12 various sites appeared to be of animals infected with Ebola.
Lahm believes “the transmission of Ebola within animal populations is much more widespread than previously believed; Ebola appears to spread both within species and between different species of animals.”
Lahm and researchers also believe that climate is another major factor in the spread of the disease. They believe that drought increases the incidence of the disease and that environmental stresses, such as drought, amplify disease transmission.
Researchers are now urging education of the public to minimize contact in the hope of reducing the spread of the disease. They hope that, by discouraging scavenging of dead animals as well as safe hunting promotion, contact with these animals will be reduced.
Source: Lahm SA, Kombila M, Swanepoel R, Barnes RF. Morbidity and mortality of wild animals in relation to outbreaks of Ebola haemmorrhagic fever in Gabon, 1994–2003. Trans. R. Soc. Trop. Med. Hyg. 101(1), 64–78 (2006).
Escherichia coli kept out of meat
Solutions used by meat processors to extend the shelf-life of meat have been found to kill pathogens, such as Escherichia coli 0157:H7. This important discovery was made by Susan Brewer and her fellow researchers from the University of Illinois (IL, USA).
Brewer believes that this is particularly important because many recycled solutions used to enhance flavor and tenderize foods, such as chops, steaks and other cuts of meat, can enhance the spread of E. coli. This fact prompted her to search for a suitable point of intervention before the meat is available to consumers in an attempt to reduce the levels of E. coli.
Brewer explained “we wanted to find a point in the process at which we could exert some kind of control to keep foodborne pathogens from becoming a problem.”
Meat is prepared in a process where all pieces of meat are injected with fluids to enhance the flavor. This improves the taste of leaner cuts of meat and is a process that has been utilized, with few adverse effects, in poultry and ham for a considerable amount of time.
“A certain amount of fat makes meat juicy and tasty, but in recent years, consumers have been demanding leaner and leaner cuts if meat. Processors are now using the needles that tenderize steaks and chops to inject solutions that make the meat taste better and last longer.”
This fluid is injected into the food and any residue is caught in a basin below. This excess fluid is then recycled back into the enhancing solution. If one piece of meat contained pathogens, it is then likely that further food could be contaminated by the recycled runoff fluid. Another problem with this method is that organisms, which may exist at the foods surface, could then penetrate to the center of the meat with the injection system. If the meat was then cooked to a rare standard, the pathogens deep within the food would not be eradicated.
Brewer and her team set out to correct this problem by conducting two studies and making themselves fully aware of the preparation process in an attempt to find an effective intervention method.
First, the team covered the meat’s surface with the indicator organism, E. coli K12, in order to track the progress of the pathogen during the production process. In the next study, E. coli K12 was incorporated into the enhancing fluid. This led to the discovery that some specific life-prolonging solutions eradicated the bacteria effectively. “In certain solutions containing sodium lactate or sodium diacetate, bacteria cells couldn’t grow and were substantially reduced. These shelf-life enhancers definitely work, and it really doesn’t make any difference whether the steak itself or the solution is contaminated,” explained Brewer.
The team advises that cooking is always the end point of the preparation process and so should be carried out at high temperatures at which point even E. coli 0157:H7 will be destroyed.
Source: Brewer MS, Rojas MC, Paulson DD, Wicklund RA. Effects of shelf-life enhancers on E.coli K12 survival in solutions used to enhance beef strip steaks. J. Food Sci. doi:10.1111/j.1750-3841.2006.00092.x (2006).
Encouraging results from HIV gene therapy
An experimental gene therapy for HIV infection has shown promising results in a Phase I clinical trial. It has proven safe and effective and likely to sustain viral loads. The Phase II trials will begin shortly owing to the encouraging results seen in the previous trial, researchers report. The study was undertaken by Carl June, Bruce Levine and coworkers at the University of Pennsylvania’s Abramson Family Cancer Research Institute (PA, USA) together with colleagues from the Gaithersberg (MD, USA).
The study occurred over 9 months and included five patients who were HIV-positive and who had developed drug resistance. All five were infused with approximately 10 billion genetically modified CD4+ T cells. The cells were manipulated in such a way as to carry a modified version of HIV, which included an antisense RNA molecule. The technique adopted by HIV to reproduce itself inside infected cells is then disturbed.
According to June, “the goal of this Phase I trial was safety and feasibility, and the results established that, but the results also hint at something much more.”
The researchers intend that the Phase II trial will include 25 patients and that they will receive higher than previously administered doses of this therapy.
The researchers are aware that there is still much work to be done if this is to become an adopted treatment for HIV. Levine admits that, even though the gene therapy “produced encouraging results in one or two patients doesn’t mean it will work for everyone. We have much more work to do.”
Others have expressed concern that the treatment may prove too expensive to be of use to those in developing countries who have HIV or AIDS. However, Martin Haas (Univerity of California, CA, USA) is positive about the new development “I think they have really significant prospects to develop this into serious anti-HIV approaches for those patients in whom HIV cannot be kept under control by chemical means.”
Source: Levine BL, June CH, Humeau LM et al. gene transfer in humans using a conditionally replicating lentiviral vector. Proc. Natl. Acad. Sci. USA 103(46), 17372–17377 (2006).