QUEENSLAND, Australia, Nov. 4 (UPI) -- Researchers tracked outbreaks of scarlet fever in Asia and Europe in the last five years, finding some drug resistance among strains and no explanation for the recent outbreaks.
Group A Streptococcus, or GAS, causes strep throat but can infect the upper respiratory tract, causing fever, sore throat, chills, abdominal pain, a swollen tongue and the characteristic sandpaper-like red rash. Scarlet fever generally occurs in children, however almost anybody can get it, according to the Centers for Disease Control and Prevention.
Since 2011, there have been more than 100,000 cases of of the highly contagious disease in China, a tenfold increase in cases in Hong Kong to 5000. A recent outbreak contributed to more than 12,000 cases in the last year in the United Kingdom.
For people who are not allergic to it, penicillin is the best treatment for scarlet fever. Other antibiotics generally treat scarlet fever effectively, however researchers at the University of Queensland in Australia found strains in the recent outbreaks resistant to drugs such as erythromycin and tetracycline.
"We now have a situation which may change the nature of the disease and make it resistant to broad-spectrum treatments normally prescribed for respiratory tract infections, such as in scarlet fever," said Dr. Nouri Ben Zakour, a researcher in the school of chemistry and molecular biosciences at the University of Queensland, in a press release. "With this heightened awareness, we can now swiftly identify scarlet fever-associated bacteria and antibiotic resistance elements, and track the spread of scarlet fever-causing GAS strains," she said.
The researchers performed genomic sequencing on isolates of 34 GAS strains from Hong Kong and mainland China to investigate genetic changes in the strains, finding several that have led to some drug resistance.
Ben Zakour said the researchers don't understand the "evolutionary forces" driving the recent outbreaks, but that bacterial determinants such strain replacement and gene acquisition, the health status of people GAS bacteria infect, and environmental elements such as rainfall or temperature could be playing a role.
Scarlet fever was deadly for many children who contracted it in the 19th and early 20th centuries but it faded for most of the last hundred years.
The disease can go away if untreated, however it can lead to complications later in life that include rheumatic heart disease, rheumatic kidney disease, arthritis and ear infections. If treated quickly with antibiotics, the complications are nearly always prevented.
The study is published in Scientific Reports.