News Scan for May 25, 2016

News brief

Antibiotic treatment of cows may increase their methane emissions

In a small study, antibiotic treatment of cows nearly doubled emissions of methane, a potent greenhouse gas, from their manure, suggesting that worries about antimicrobial resistance may not be the only reason to use caution with antibiotics in farm animals, according to a report today in the Journal of the Royal Society B.

In the experiment, conducted in Finland, an international team of researchers treated five cows with tetracycline for 3 days and used five other cows as controls. A day's worth of fresh dung was collected beginning an hour after the last antibiotic dose, and dung emissions of carbon dioxide, methane, and nitrous oxide were measured.

The team found no significant difference in carbon dioxide or nitrous oxide emissions between the treated and untreated cows, but about 80% more methane was emitted from the manure of treated cows, the report says.

The researchers also placed dung beetles in some of the dung samples and observed that antibiotic treatment "restructured" the beetles' microbiota, though it did not affect the insects' size or numbers.

The authors said their study appears to be the first to show an increase in methane emissions associated with antibiotic treatment in livestock. They observe that tetracycline and some other antibiotics are less effective against archaea—primitive, nonbacterial single-celled microbes—than against bacteria. They propose that by suppressing bacteria in the gut and in dung, antibiotics enable methane-producing archaea to outcompete bacteria for hydrogen, thus increasing their methane output.

Methane emissions from cattle manure are typically lower than those from cattle belching, but they still make up a sizable share of the total, the researchers write. They suggest that future research should focus on antibiotic effects on methane from belching.
May 25 J Royal Soc B abstract


Study finds MERS-CoV antibodies in camel calves for first 5 to 6 months

Camel calves lose maternal MERS-CoV antibodies about 5 to 6 months after birth and are susceptible to infection, indicating a possible window for vaccination, according to a study today in Emerging Infectious Diseases.

German and United Arab Emirates (UAE) scientists monitored levels of antibodies specific to MERS-CoV (Middle East respiratory syndrome coronavirus) in 11 camel mothers and their calves for 1 year after birth. The animals were part of a 4,500-camel herd in the UAE, and the calves were born in early June 2014. The researchers collected nasal swabs and serum specimens on the day of birth, after 1 week, after 1 month, and then every month after that.

On the day of calving, MERS-specific antibodies were high in all camel mothers studied but could not be detected in the calves. A week later, however, all 11 camel calves had high MERS-CoV–specific antibody levels. At 5 to 6 months after birth MERS-CoV antibodies were not detected in 6 calves and were at low levels in the other 5—at 1:20 to 1:40 neutralizing titers.

The researchers also tested for MERS-CoV shedding in nasal swab specimens and detected sporadic shedding on days 7 and 30 in some calves. At 6 months, 2 of the 11 calves had detectable RNA in their blood, indicating an active infection.

The authors conclude, "Our findings have important implications for the prevention of human infections through camel herd management and camel vaccination. Camel breeding, even if involving a small number of newborn animals, should be classified as a risk for human acquisition of MERS-CoV."
May 25 Emerg Infect Dis study


NIAID awards Soligenix $3.2 million for animal studies of ricin vaccine

The National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health has exercised an option to fund animal efficacy and toxicology studies for Soligenix's RiVax ricin vaccine as a bioterror preparedness measure, the company said in a news release today.

The option provides the company $3.2 million in additional funding, bringing Soligenix's contract with the NIAID up to $16.7 million. If all contract options are exercised to advance a heat-stable RiVax to the approval stage, the total award will be $24.7 million, the company said.

Ricin is a plant toxin and potential biological weapon because of its stability, potency, and availability as a byproduct of castor oil production. It comes in many forms such as powder, mist, or pellet and can also be dissolved in liquid.

Phase 1 trials of RiVax with and without an immune-boosting adjuvant demonstrated safety and immune response in adult volunteers, according to the release.
May 25 Soligenix news release

Flu Scan for May 25, 2016

News brief

Study inconclusive on bias as factor in low flu-vaccine uptake in minorities

A new survey study hints that perceived discrimination may be a factor in low influenza vaccine uptake in racial and ethnic minorities, but the researchers found that it was not significant in comparison with other factors, such as education, according to a report in Medical Care.

Trying to find out why minorities are less likely to get flu shots, the researchers analyzed survey responses from 8,127 white, black, and Hispanic Americans with chronic diseases. The survey was part of an independent evaluation of a national healthcare quality improvement project sponsored by the Robert Wood Johnson Foundation, according to a press release from Wolters Kluwer Health, which publishes Medicare Care.

About 7% of the respondents reported feeling that they were victims of healthcare discrimination at some time in their lives. Of those who perceived discrimination, 32% said they had received a flu vaccine, versus 60% of those who did not perceive discrimination.

The authors said that perceived discrimination, examined alone, accounted for 16% of the racial/ethnic disparity in receipt of the flu vaccine, according to the release. But when they adjusted for other factors that affect flu vaccine uptake, the contribution of perceived bias dropped to 6% and was no longer significant, the report says.

That finding may reflect the relatively low prevalence of perceived discrimination in the nationwide survey, and larger studies might show a significant effect, according to the release.

Three factors were found to be linked with a higher probability of vaccination: having a college degree, nonsmoking status, and trusting the information provided by one's doctor.

"The causes of persistent racial/ethnic disparities are complex and a single explanation is unlikely to be sufficient," the researchers wrote.
June 2016 Medical Care report
May 24 Wolters Kluwer Health press release



Study finds differences in isolated H7N9 cases vs clusters

A study yesterday of 72 isolated H7N9 avian flu cases, 17 family clusters, and 8 clusters tied to live-bird markets in China found that case-fatality rates (CFRs) did not differ among the groups, but sporadic cases tended to involve younger patients with fewer underlying medical conditions.

Researchers from China, Taiwan, and Egypt noted in the International Journal of Infectious Diseases that the family clusters involved human-to-human transmission, whereas the live-market clusters involved co-exposure to the poultry environment. They analyzed primary versus secondary cases for both types of clusters.

The CFRs did not differ statistically among the groups:  36% for sporadic cases, 26% for the family clusters, and 29% for the live-market clusters. The groups differed, however, by average age (36 vs 60 vs 58 years, respectively), co-morbidities (31%, 60%, 54%), avian exposure (72%, 100%, 83%), and H7N9-positive rate (20%, 64%, 35%).

The investigators found no statistical differences between primary and secondary cases in the live-market clusters. In the family clusters, however, incidence of mild cases (6% vs 32%), history of visits to a live-bird market (100% vs 59%), exposure to both birds and infected humans (12% vs 55%), and median days from onset to antiviral treatment (6 vs 3 days) differed significantly from the index to the secondary cases.

The authors attributed the difference in disease severity in the family clusters to older age and greater underlying disease in the primary case-patients.
May 24 Int J Infect Dis study

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