News Scan for Aug 13, 2019

H5N2 airborne spread
Chlamydia vaccine trial findings
Farm Bill animal health activities

Study adds more support for airborne avian flu spread in US outbreaks

A modeling study that incorporated air movement patterns from farms affected early in the highly pathogenic H5N2 avian influenza outbreak that hit US poultry in 2015 suggests that most affected farms in Iowa may have received airborne virus from farms within and outside the state. Using a model used for other animal pathogens such as foot-and-mouth disease virus, researchers published their findings today in Scientific Reports.

The outbreaks led to $3 billion in economic losses over 7 months, striking 232 farms in 15 states. A federal assessment of the outbreak found no one clear factor, but said the virus likely spread by multiple routes, including biosecurity gaps and possibly airborne transmission. There are also anecdotal reports that abnormal bird deaths began near air inlets of infected poultry barns.

In analyzing the model findings, researchers said the majority of infected farms in Iowa might have received airborne virus carried by fine particulate matter from farms within the state or infected farms in neighboring states. Though the modeled airborne virus concentrations never rose above the minimal infective dose for poultry, continuous exposure may have increased the risk, the group wrote.

They concluded that the probability of airborne highly pathogenic avian influenza infection could be affected by flock size and distance from earlier affected farms. "And more importantly, it can be markedly reduced by swift depopulation and inlet air filtration," the team added.
Aug 13 Sci Rep abstract


First clinical trial of chlamydia vaccine yields promising findings

The first phase 1 trial of a chlamydia vaccine found that it is safe and provokes an immune response. A team from Denmark and the United Kingdom reported their findings yesterday in The Lancet Infectious Diseases.

As the most common sexually transmitted bacterial infection, chlamydia causes about 131 million new cases each year, which experts say is likely an underestimate, because three out of four cases are asymptomatic. Vaccination has been eyed as a good way to curb the epidemic, but so far no other vaccine candidates have reached the clinical trial stage.

The vaccine, called CTH522, is based on the outer membrane protein of the Chlamydia trachomatis bacterium. The team analyzed two formulations, one with added CAF01 liposomes to boost cellular immunity and one with aluminum hydroxide to boost antibodies. Thirty five women not infected with chlamydia were randomly assigned to three different groups—two with the new vaccine combined with either CAF01 or aluminum hydroxide and one to placebo. The vaccine was given in three intramuscular injections and two intranasal boosts.

Researchers found that both formulations provoked an immune response in 15 of 15 women in both vaccine groups. However, the formulation combined with CAF01 produced 5.6 times more antibodies, suggesting that it should be evaluated for further study.

The team cautioned that though the vaccine prompted an immune response, it's still not clear if it translates into protection. In a Lancet press release, first author Helene Juel, PhD, with the Statens Serum Institute in Denmark, said both versions of the vaccine raised the concentrations of vaginal antibodies that in mouse studies were shown to be the first line of defense against chlamydia. She added that it will take many more years of research before a vaccine is available, but researchers are planning a phase 2a study of the CAF01 version of the vaccine.
Aug 12 Lancet Infect Dis abstract
Aug 12 Lancet press release


APHIS announces animal health activities funded by Farm Bill

Yesterday the U.S. Department of Agriculture's (USDA's) Animal and Plant Health Inspection Service (APHIS) announced plans for new animal health activities funded by the 2018 Farm Bill.

The 2018 Farm Bill established a three-part program to support animal disease prevention and management, through the creation of two new programs: the National Animal Vaccine and Veterinary Countermeasures Bank (vaccine bank) and the National Animal Disease Preparedness and Response Program (NADPRP), the USDA said in a press statement. The bill also expands funding opportunities for the existing National Animal Health Laboratory Network (NAHLN).

"For 2019, APHIS will also make available up to $10 million in funding to be divided between NADPRP and NAHLN based on the quality of proposed projects," the press statement said.  "Once fully implemented, these three programs will work together to protect and improve the health of our nation's livestock, helping farmers and ranchers provide high-quality agricultural products to consumers here and abroad."

Both the vaccine bank and the NADPRP will help protect American livestock from outbreaks of foot-and-mouth disease or other high-impact foreign animal diseases.
Aug 12 USDA press release

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