Mosquito gut bacteria may inhibit malaria parasite, researchers say
BALTIMORE, Md. Bacteria in the gut of a mosquito may inhibit infection of Plasmodium falciparum, the parasite that causes malaria in humans, according to researchers at the Johns Hopkins Bloomberg School of Public Health.
Scientists with the Bloomberg School’s Malaria Research Institute found that removing these bacteria, or microbial flora, with antibiotics made the mosquitoes more susceptible to Plasmodium infection because of a lack of immune stimulation. Their study is published in the May 8, edition of the journal PLoS Pathogens.
“Our study suggests that the microbial flora of mosquitoes is stimulating immune activity that protects the mosquito from Plasmodium infection,” stated George Dimopoulos, senior author of the study and associate professor with Johns Hopkins Malaria Research Institute. “The same immune factors that are needed to control the mosquito’s infection from the microbes are also defending against the malaria parasite Plasmodium. … The interplay between bacteria and the mosquito’s immune system may have significant implications for the transmission of malaria in the field where mosquitoes may be exposed to different types of bacteria in different regions. Theoretically, these bacteria could be introduced to the mosquitoes to boost their immunity to the malaria parasite and make them resistant and incapable of spreading the disease. Our current research aims at identifying those bacteria that trigger the strongest mosquito immune defense against the malaria parasite.”
Malaria kills more than one million people worldwide each year; the majority of deaths are among children living in Africa.
Food intake may contribute more to obesity than lack of exercise, study suggests
AMSTERDAM Conventional wisdom has it that the American obesity epidemic results from lack of exercise, but a study presented in the Netherlands Friday suggests otherwise.
The study, led by researchers in Australia and presented at the 17th European Congress on Obesity in Amsterdam, indicates that while exercise remains important, the main cause of the obesity epidemic is that Americans eat too much.
“To return to the average weights of the 1970s, we would need to reverse the increased food intake of about 350 calories a day for children and 500 calories a day for adults,” lead study author Boyd Swinburn of Australia’s Deakin University said in a statement. That would mean eliminating a can of soda or small portion of French fries from a child’s diet or a large hamburger from an adult’s.
The researchers started by testing 1,399 adults and 963 children to find how many calories they burn on an average day. They combined those results with national food supply data on how much food Americans ate between the 1970s and early 2000s. They then calculated how much weight they would expect Americans to have gained in the 30-year period if food intake were the sole influence, using national survey data that recorded the weight of Americans during that period.
“For adults, we predicted that they would be 10.8 kg heavier, but in fact they were 8.6 kg heavier,” Swinburn said. “That suggests that excess food intake still explains the weight gain, but that they may have been increases in physical activity over the 30 years that have blunted what would otherwise have been a higher weight gain.”
According to the Centers for Disease Control and Prevention, more than 30% of American adults are obese, which health experts define as having a body mass index of 30 or greater.
Study: Taking probiotics during pregnancy may reduce obesity risk after birth
LONDON One year after giving birth, women are less likely to have the most dangerous kind of obesity if they had been given probiotics from the first trimester of pregnancy, according to new research released Thursday by the European Association for the Study of Obesity.
“The results of our study, the first to demonstrate the impact of probiotics-supplemented dietary counselling on adiposity, were encouraging,” stated Kirsi Laitinen, a nutritionist and senior lecturer at the University of Turku in Finland, who presented her findings May 7 at the European Congress on Obesity. “The women who got the probiotics fared best. One year after childbirth, they had the lowest levels of central obesity as well as the lowest body fat percentage.
“Central obesity, where overall obesity is combined with a particularly fat belly, is considered especially unhealthy,” Laitinen said. “We found it in 25% of the women who had received the probiotics along with dietary counseling, compared with 43% in the women who received diet advice alone.”
Laitinen said further research is needed to confirm the potential role of probiotics in fighting obesity. One of the limitations of the study was that it did not control for the mothers’ weight before pregnancy, which may influence how fat they later become.
“The advantage of studying pregnant women to investigate the potential link between probiotics and obesity is that it allows us to see the effects not only in the women, but also in their children,” she said. “Particularly during pregnancy, the impacts of obesity can be immense, with the effects seen both in the mother and the child. Bacteria are passed from mother to child through the birth canal, as well as through breast milk and research indicates that early nutrition may influence the risk of obesity later in life. There is growing evidence that this approach might open a new angle on the fight against obesity, either through prevention or treatment.”
Latinen’s study was funded by the Social Insurance Institution of Finland, the Academy of Finland and the Sigrid Juselius Foundation, a Finnish medical research charity.