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Archive - Apr 14, 2017

Lice and Their Bacterial Sidekicks Have Evolved Together for Millions of Years

A Florida Museum of Natural History study provides new insights into the complex, shared history between blood-sucking lice and the vitamin-producing bacterial sidekicks that enable them to parasitize mammals, including primates and humans. The study was published online on April 14, 2017 in Molecular Biology and Evolution. The study is titled “Primates, Lice and Bacteria: Speciation and Genome Evolution in the Symbionts of Hominid Lice.” Lice depend on bacteria to supply essential vitamins missing from blood, their only food source. These bacterial partners live in specialized cells inside their insect hosts and pass from a female louse to her offspring. Lice could not survive without their symbiotic bacteria, and the bacteria, in turn, cannot live outside their insect hosts. When their partnership began, however, and how it has evolved over time have been unclear. Previous studies suggested lice acquired and replaced their bacterial symbionts multiple times over their evolutionary history. But a study by Florida Museum researchers Bret Boyd, Ph.D., and David Reed, Ph.D., found that lice that parasitize primates and humans have hosted their endosymbionts continuously for at least 20 to 25 million years, aligning with the time period during which great apes and old world monkeys shared a common ancestor. As primates evolved, so did lice, and the evolution of their bacterial partners stayed closely in step. The data provide a new perspective on the evolutionary tree of these symbiotic bacteria, said Dr. Boyd, who conducted the research as a doctoral student at the museum. "While lice are highly maligned, they provide a wealth of scientific information," said Dr. Boyd, now a postdoctoral researcher at the University of Georgia and the study's first author.

First Large-Scale Survey of Chagas Disease in US Confirms “Silent Killer” Is a Major Public Health Challenge for Country; Importance of Early Detection & Treatment Emphasized

A study of almost 5,000 Latin American-born residents of Los Angeles County found that 1.24% tested positive for Chagas disease, a parasitic infection that can cause life-threatening heart damage if not treated early. This was announced in an April 13, 2017 press release from the Drugs for Neglected Disease initiative. The referenced study was published online on February 12,2017 in Clinical Infectious Diseases. The open-access article is titled “Prevalence of Chagas Disease in the Latin American-born Population of Los Angeles.” Chagas disease is one of the leading causes of heart failure in Latin America. This is the first epidemiological study to back up the Centers for Disease Control and Prevention's (CDC) estimate that approximately 300,000 people are living with this disease in the United States. The parasite that causes Chagas disease, Trypanosoma cruzi, is transmitted mainly by the bite of the triatomine bug (photo), which is found throughout the Americas. Roughly 30% of those infected will develop serious cardiac, digestive, or neurological disorders. The disease is not generally transmitted from person-to-person. "Less than 1% with the infection are receiving treatment for Chagas disease," said Dr. Sheba Meymandi, Director of the Center of Excellence for Chagas Disease (CECD) at Olive View-UCLA Medical Center and the study's lead author. "Without treatment, many Chagas patients are at risk of a ‘silent death’ due to heart failure. Our study demonstrates the need for similar research in other states, and underscores the critical importance of early detection and treatment to tackle this public health challenge in the US." The study was coordinated by the CECD, the first and only center of excellence for the diagnosis and treatment of Chagas disease in the US.