NEWS SCAN: Avian flu in Mexico, adjuvanted flu vaccine, fight over GM mosquitoes, cholera in Sahel

Jul 11, 2012

Mexico culls 2.5 million chickens to curb H7N3 outbreak
Mexico's agriculture ministry said yesterday that 2.5 million chickens have been culled over the past 3 weeks to control outbreaks of highly pathogenic H7N3 avian influenza that have struck commercial farms in the western part of the country, the London-based Telegraph reported today. Authorities have visited 148 poultry farms. The virus was found on 31 farms, tests were negative on 34, and results were pending on the rest. Mexico had imported 1 million poultry vaccine doses from Pakistan, and farming officials said they have developed vaccine seed to make a projected 80 million doses at four laboratories, according to the story. On Jul 2 Mexico declared a national animal health emergency to launch more intensive control efforts, which include quarantine, vaccination, and culling of infected birds. The outbreak began on Jun 13 on commercial farms in Jalisco state. The event is Mexico's first highly pathogenic avian flu outbreak in poultry since the mid 1990s.
Jul 11 Telegraph story

Study: Adjuvant boosts immune response to H1N1 vaccine in young and old
In a US study conducted during the 2009 flu pandemic, the AS03 adjuvant increased the immune response to an H1N1 flu vaccine in both young and elderly adults, according to an early online report in the Journal of Infectious Diseases. The adjuvant, which has been used in vaccines in Canada and Europe, was mixed into the vaccine just before administration. The researchers, from several different institutions, recruited 544 volunteers ages 18 to 64 and 245 volunteers ages 65 and older. They were randomly assigned to receive two doses of 1 of 5 vaccine formulations: 3.75, 7.5, or 15.0 micrograms (mcg) with AS03, or 7.5 or 15.0 mcg with no adjuvant. Immune response was measured by hemagglutination inhibition antibody titer. After one dose, the immune response in both age-groups to any dose of the adjuvanted vaccine was higher than the response to the 15-mcg dose without adjuvant, and the difference was significant for the adjuvanted versus unadjuvanted 15-mcg doses. A second dose of adjuvanted vaccine yielded further increases in immune response, whereas a second dose of unadjuvanted formulation did not "substantially enhance" the response. Also, the adjuvant was linked to greater persistence of the immune response at 6 months. In other findings, responses in older volunteers were considerably lower than in the younger ones, and prior receipt of seasonal flu vaccine was associated with a lower response to the pandemic vaccine. The vaccines were generally well tolerated, though local adverse events were more common with the adjuvanted vaccines.
Jul 10 J Infect Dis abstract
Accompanying J Infect Dis editorial (access requires subscription)

Florida protestors say no to dengue-curbing, genetically modified mosquitoes
Almost 90,000 signatures have been gathered by a Key West, Fla., woman protesting the planned release of genetically modified mosquitoes to curb the spread of dengue fever, says a Jul 10 article in The Guardian. The woman is concerned about the potential effects of the mosquito release on the ecosystem of the Florida Keys and claims that the locals were not listened to in planning for the release. The mosquitoes were developed by the British company Oxitec; males of Aedes aegypti, the species that carries dengue,have a mutation that renders them sterile and thus reduces the species population. The mosquitoes were released for the first time in 2009 in the Cayman islands, and tests there suggested that the number of A aegypti mosquitoes could be reduced by about 75% over a year, the Guardian article says.
Jul 10 Guardian article
Elsewhere, a report yesterday from Agence France-Presse said Brazil plans to breed hordes of genetically modified mosquitoes to slow the spread of dengue there. A factory in the northeastern Brazilian state of Bahia will produce 4 million mosquitoes per week, AFP reported. The Health Ministry claims that the mosquito population has been reduced by 90% in two towns where the mosquitoes were tested.

Cholera surge reported in Africa's Sahel
A recent upsurge in cholera cases in Africa's Sahel region has sickened about 2,800 people and killed more than 60, said an alert from the United Nations Children's Fund (UNICEF) yesterday. The region covers the area from the Atlantic Ocean to the Red Sea and includes Chad, Mali, Mauritania, Niger, and northern Cameroon and Nigeria. While cholera is a recurrent threat in the area, the recent pace of cases is a concern because of the upcoming rainy season and the large number of people in the area who have been displaced by conflict in northern Mali, according to UNICEF. The affected region is already facing a food crisis, and malnourished children are at special risk. "Malnutrition, displacement, and now rains in some parts of the Sahel create the ideal breeding ground for cholera, which hits young children hardest," said a UNICEF official in a news release. In 2011, more than 67,000 cholera cases were reported from Chad, Cameroon, and Nigeria, with 2,153 deaths and an average case-fatality rate of 3.2%.
Jul 10 UNICEF news article
Jul 10 UNICEF news release

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