Research Roundup: Swine flu, drug resistance, and hepatitis C cures
In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week.
The location of pig farms can influence human flu patterns, as farmworkers may be among the first exposed to new strains of swine flu. Researchers at Duke University compared a map of North Carolina’s concentrated animal feeding operation (CAFOs) to the location and timing of flu outbreaks in the state, concluding that counties with high numbers of CAFOs experience early peaks of flu cases during years in which a strain of swine flu is in circulation. However, the same effect was not seen in years when the most common strains of influenza did not originate in pigs. The trend is likely attributable to transmission of swine flu from pigs to farmworkers, and subsequently to their family and friends. While efforts targeting CAFOs, such as animal surveillance or vaccination, could decrease human risk for swine flu, a more affordable and immediate solution is for farmworkers and their families to get a flu shot as early as possible each year.
Extensively drug-resistant tuberculosis (XDR TB) may be more infectious than previously believed, according to new research out of South Africa. Tuberculosis (TB) is difficult to treat as patients must take multiple pills a day over months or even years. When patients are unable to complete the regimen, the bacteria can grow resistant to the medicines, resulting in multidrug-resistant and XDR TB. However, a study of 404 XDR patients in South Africa suggests that only one-third of cases are due to treatment failures, whereas the remaining cases resulted from person-to-person transmission. These findings indicate that combatting XDR TB will require both improved treatment for TB patients and enhanced prevention and detection efforts.
A common fungal infection, Candida auris, is growing increasingly drug resistant. Strains that are resistant to all three classes of antifungals have been reported in five continents. As with antibiotic resistance, antifungal resistance has emerged as a result of inappropriate and overuse of antifungals, and while it may not be as widespread, there are fewer classes of antifungals, providing few alternatives if a treatment fails. An investigation of 54 samples of C. auris found that nearly all were resistant to the first-line medicine (fluconazole), 22 were resistant to both the first and second-line treatments, and 2 were resistant to all three classes of antifungals. Further, standard approaches to disinfecting hospital rooms and equipment are insufficient to eliminate C. auris, increasing the risk of hospital-acquired infections. While cases remain limited, the fungus has an extremely high fatality rate, killing 60 to 70 percent of those infected.
Nine recently approved and widely used hepatitis C medicines may have serious, unexpected side effects, including liver failure. The new antivirals cure nearly all patients, have fewer side effects than older medicines, and significantly shorten the duration of treatment. However, a new report published by the Institute for Safe Medication Practices details adverse effects, including potentially fatal liver failure and reactivation of the closely related hepatitis B. At this time, cases are rare and the findings are inconclusive, as the Institute did not have access to patients’ medical records that could shed light on whether the side effects preceded treatment. Now, the Food and Drug Administration is calling on physicians to screen and monitor for hepatitis B in patients taking the new medicines, and a similar approach might be needed to rule out the risk of liver failure.