Posted: 20 October 2011
WASHINGTON: US researchers have uncovered the genetic mechanism that bed bugs use to resist powerful insecticides, according to a study published Wednesday, leading to the hope of more effective ways to combat the pests.
Bed bugs, which have been largely absent from the United States since the 1950s, have returned in force in the last decade in the US, and notably other Western countries in Europe.
They have, in this time, developed unique resistance to the insecticides that are mainly used against them -- deltamethrin and beta-cyfluthrin, both leading pyrethroids.
The genetic research released Wednesday in the journal PLoS One, published by the Public Library, offers new hope to understand their resistance and find new ways to eradicate the blood-sucking bugs.
"Different bed bug populations within the US and throughout the world may differ in their levels of resistance and resistance strategies, so there is the need for continuous surveillance," said lead author Zach Adelman, associate professor of entomology at Virginia Tech.
Adelman and the other researchers in the study assessed two populations of bed bugs -- "a robust, resistant population" found in 2008, and a "non-resistant population" that has been raised in a lab since 1973.
The study determined how each strain succumbed to the pyrethroids, if at all, and determined that over a 24 hour period it required "5,200 times more deltamethrin or 111 times more beta-cyfulthrin" to kill the modern bed bugs compared to the older specimens.
The bed bug's bite is a little painful rather than dangerous, but many people are scared because the creature mainly attacks when people are asleep.
-AFP/pn
Taken from ChannelNewsAsia.com; source article is below:
US researchers study bed bugs' resistance
A month later, and is the promising holding up?
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Posted: 19 October 2011
WASHINGTON: The search for the world's first malaria vaccine received a boost Tuesday with the release of early results from a major clinical trial showing it cut risk by about half in African children.
The vaccine known as RTS,S is made by the British pharmaceutical giant GlaxoSmithKline's lab in Belgium, and is the first of its kind to attempt to block a parasite, rather than bacteria or viruses.
Experts hailed the phase III trial under way at 11 sites in sub-Saharan Africa as a promising step toward eradicating the ancient mosquito-borne disease that kills almost 800,000 people yearly, most of them children.
The results are published online in the New England Journal of Medicine, and were simultaneously announced at the Malaria Forum hosted by the Bill & Melinda Gates Foundation in Seattle, Washington.
In a statement, philanthropist and Microsoft tycoon Bill Gates described the findings as a "huge milestone" in the fight against malaria, that "has the potential to protect millions of children and save thousands of lives."
Children aged five to 17 months who received three doses of the vaccine saw a 56 per cent lower risk of developing clinical malaria, which causes high fever and chills, according to the study.
When it came to severe malaria -- the stage of the illness that can be fatal and reaches the blood, brain or kidneys -- those who received the vaccine showed a 47 per cent lower risk.
"This is remarkable when you consider that there has never been a successful vaccine against a human parasite," said Tsiri Agbenyega, who chairs the RTS,S Clinical Trials Partnership and heads malaria research at Komfo-Anokye Teaching Hospital in Kumasi, Ghana.
"While these results are encouraging, we still have a ways to go," he told reporters.
The analysis was done with data from 6,000 children in the trial over a 12-month follow up after vaccination.
More data is needed from the younger age group -- infants aged six to 12 weeks -- to better assess how well it works in this particularly vulnerable group, experts said. Additional results from the younger set are due next year.
The World Health Organization says malaria claimed 781,000 lives in 2009. About 90 per cent of malaria deaths each year occur in Africa and 92 per cent of those are children less than five years old.
Asked whether the Gates Foundation would get behind a vaccine with a success rate of only about half, Regina Rabinovich, director for infectious diseases at the foundation's global health program, was circumspect.
"This is a key question. The group will ultimately want to understand efficacy, duration and safety," she said, adding she was "enthusiastic" about the results so far and was awaiting further data.
More than 15,000 children in seven African countries are enrolled in the trial, which is set to continue for two more years, and covers areas with other interventions in place against malaria, such as bed nets and spraying.
RTS,S was created in 1987 in GlaxoSmithKline Biologicals' lab in Belgium. Testing began on healthy adults in Europe and the United States in 1992, before the first Africa study started in Gambia in 1998.
Trial sites are now located in Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique and Tanzania, including 15,460 infants and young children in what GSK described as "the largest malaria vaccine trial to date."
The vaccine works by triggering the immune system to defend the body against Plasmodium falciparum, the deadliest type of malaria parasite.
Side effects included fever and swelling at injection site, "what you would typically see in other childhood vaccinations," said Agbenyega.
Several questions remain, including how the long the vaccine may last and how much it will cost, said Seth Berkley, CEO of the Global Alliance for Vaccines and Immunization (GAVI Alliance).
Malaria "is a huge problem for the poorest of the poor, and there has been a search for vaccines for as long as I can remember," he told AFP. "So to have success, even if not perfect, is a really big deal."
The US Centers for Disease Control and Prevention hailed the findings as "a promising advance in development of a malaria vaccine for African children."
GlaxoSmithKline CEO Andrew Witty said the company had already invested US$300 million to develop the vaccine and aims to produce it at a low cost with no profit, though he said it was too early to set a price.
"We are hopeful that we will be able to bring this vaccine to children in Africa by 2015," Witty said.
- AFP/ck
Taken from ChannelNewsAsia.com; source article is below:
'Promising' step for world's first malaria vaccine
