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No flight, no bite: 'Mosquito grounding' bed net nearly halves malaria infection in Tanzanian children: First new insecticide for 40 years that's shown to be safe and effective for use on nets could save many young lives – Science Daily

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A novel class of bed net that kills mosquitoes resistant to traditional insecticides by making them unable to move or fly, significantly reduces malaria infection in children, according to new research published in The Lancet.

Unlike other insecticides which kill the mosquito via the nervous system, the effects of the new bed net mean the mosquito dies from starvation or being unable to fend for itself.

The two-year community randomised trial involved more than 39,000 households and followed over 4,500 children aged 6 months to 14 years in Tanzania. It found that a long-lasting insecticidal net treated with two insecticides, chlorfenapyr and pyrethroid (chlorfenapyr LLIN), reduced the prevalence of malaria by 43% and 37% in the first and second year respectively, compared to the standard pyrethroid only long-lasting insecticidal net (LLIN).

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Chlorfenapyr LLIN also reduced clinical episodes of malaria by 44% over the two years and the number of malaria-infected mosquitoes captured by 85%.

The study was conducted by the London School of Hygiene & Tropical Medicine (LSHTM), National Institute for Medical Research, Kilimanjaro Christian Medical University College in Tanzania, and the University of Ottawa, Canada.

Long-lasting insecticidal nets are the cornerstones of malaria control in sub-Saharan Africa. However, in the past few years the decline in malaria has stalled and even reversed in some countries. In 2020, there were 627,000deaths from malaria, mainly in Africa and occurring mostly in children.

Malaria’s resurgence is partly due to the bed nets’ effectiveness being compromised by widespread resistance to pyrethroid insecticides in Anopheles mosquitoes. Chlorfenapyr works very differently to pyrethroid, causing wing muscle cramps that stop the flight muscles from functioning. This prevents mosquitoes from making further host contacts or biting, ultimately leading to their death.

The research team says the novel net could lead to significant malaria control gains in sub-Saharan Africa, but more research is needed to examine feasibility of scale-up, and on resistance management strategies needed to preserve their effectiveness long term.

Dr Jacklin F. Mosha from the National Institute for Medical Research, Tanzania, the study’s first author, said: “Malaria remains a huge problem across sub-Saharan Africa and is one of the leading causes of death in Tanzania. We urgently need new interventions to get control efforts back on track and protect young people from this deadly disease. These exciting results highlight that we have another effective tool to help control malaria.”

Children from 72 villages in Misungwi, where high levels of resistance to pyrethroids have been reported, were randomised into groups and received one of three of the most promising new generation of bed nets. Children were then tested for malaria at the end of each rainy season.

After 24 months, malaria infection was reduced by 37% in children that received the chlorfenapyr LLIN (326/1272) compared to those receiving standard pyrethroid LLIN (549/1199).

A bednet treated with a piperonyl butoxide (PBO) to enhance the potency of pyrethroid reduced malaria infection by 27% over the first 12 months of the trial, but after two years malaria infection in this group was similar to the standard net. This is likely due to it being used less regularly as holes appeared in this net more quickly.

A third type of bednet, treated with pyrethroid and pyriproxyfen which sterilises female mosquitoes, had little additional effect compared to the standard pyrethroid net. The reason is not fully understood but likely due to insufficient pyriproxyfen remaining on the net over time.

Dr Manisha Kulkarni, a scientist at the University of Ottawa’s Faculty of Medicine, said: “By essentially ‘grounding’ the mosquito, our work on adding chlorfenapyr to standard pyrethroid bed nets has great potential to maintain control of malaria transmitted by resistant mosquitoes in Africa.”

The higher costs of the chlorfenapyr LLIN were offset by the savings from reducing the number of malaria cases requiring treatment. Distributing chlorfenapyr nets is therefore expected to cost households and society less overall than standard, PBO, or pyriproxyfen nets.

Dr Natacha Protopopoff, from LSHTM and study Principal Investigator, said: “We’ve shown chlorfenapyr LLINs are safe, decrease malaria infection in children and are cost-effective. This is important evidence for the World Health Organization and malaria control programmes when they are assessing whether these new nets should be deployed in areas of insecticide resistance when standard bed nets have failed.

“However, caution is needed. The massive scale-up of standard pyrethroid LLINs 10-20 years ago led to the rapid spread of pyrethroid resistance. The challenge now is to preserve chlorfenapyr’s effectiveness by developing rational resistance management strategies.

“National malaria control programs and stakeholders should urgently advocate for better textile and insecticide durability for all novel classes of bed nets to maximise their longevity and potential.”

LSHTM scientists first identified the potential of the chlorfenapyr insecticide on malaria mosquitoes almost 20 years ago. The chlorfenapyr LLIN was subsequently developed by the manufacturer BASF in Germany, together with LSHTM.

Professor Mark Rowland, from LSHTM, explained: “When it comes to resistance to standard nets we were running out of options, but chlorfenapyr has come to the rescue. Although it may appear this has happened overnight, in reality there were twists and turns over many years to show how the new class of insecticide truly works ,to develop improved formulations to confirm effectiveness and safety on nets, and finally to demonstrate control of malaria in large scale trials.

“What really threw us for a long time was that in daytime tests the chlorfenapyr was not very toxic to the mosquito, but at night when the malaria mosquitoes naturally fly up against the treated bednet it gets a severe case of muscle cramps so it buckles and falls to where it is likely to be carried off by scavenging ants. No other mosquito insecticide works like this, and because of the unique mode of action it kills all kind of mosquito that have evolved resistance to other insecticides. It should have a long future.”

Professor Franklin W. Mosha, Principal Investigator from the Kilimanjaro Christian Medical College, Tanzania, said: “This achievement has only been made possible through partnership between research institutes, manufacturing industry and funding agencies like the Bill & Melinda Gates Foundation and then the Innovative Vector Control Consortium We can all take pride in our respective roles in getting us to this exciting point.”

The authors acknowledge limitations of the study, including the rapid decrease in use of trial LLINs, within a context of high overall net usage, which may in part explain the relative lack of effectiveness of PBO LLINs and pyriproxyfen LLINs over the two years compared to standard LLINs.

This is the first of two trials of chlorfenapyr nets. The second in Benin in West Africa with the Centre de Recherche Entomologique de Cotonou and LSHTM is due to report later this year. This will confirm if chlorfenapyr LLINs are also more effective in a different malaria setting and if pyriproxyfen LLINs could perform better when net usage is higher.

The research was funded by the Joint Global Health Trials: Foreign, Commonwealth and Development Office, Medical Research Council, Wellcome and Department of Health and Social Care.

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New technology to advance women’s cancer care at Southlake

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NEWS RELEASE
SOUTHLAKE REGIONAL HEALTH CENTRE
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This Cancer Awareness Month, Southlake is adding advanced technologies to detect and treat breast cancer and other women’s cancers thanks to generous community donor support, most recently through the HERE is Where Cancer Meets its Match campaign. New cancer care technology, including new mammography machines, the MyoSure System and the MOLLI 2® System will make a measurable impact in diagnosing and treating women’s cancers in the communities Southlake serves.

Southlake is installing three new mammography machines to expand its breast cancer screening program to 1,500 more women each year. Two of these machines have new biopsy capabilities that will reduce the number of cancelled exams due to equipment failure, ensuring timely care for women. Women ages 40 to 49 years old will be able to self-refer for publicly funded mammograms through the Ontario Breast Screening Program starting this fall.

“Early detection is critical when treating breast cancer and other women’s cancers,” said Lorrie Reynolds, Director, Regional Cancer Program at Southlake. “We treat more than 1,700 breast cancer patients at Southlake every year. By adding advanced technology, like the new mammography machines, we’re ensuring women have the best experience at Southlake.”

Southlake is also introducing the MyoSure System, an innovative technology that can help detect female reproductive cancers. Damaged tissue in a woman’s uterus such as fibroids and polyps can now be removed in a precise, minimally invasive procedure that leaves the rest of the uterus intact. This will improve the overall patient experience by supporting faster recovery, reducing the risk of infection and giving more women the option to have children. An estimated 200 women per year will benefit from the MyoSure System.

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The new mammography machines and the MyoSure System build on Southlake’s recent investment in the MOLLI 2® System, a made-in-Canada wire-free breast localization technology.  This technology is considerably less invasive and more accurate when compared to wire-guided localization, resulting in a better patient experience and improved cosmetic outcomes.  More than 200 women each year will benefit from this innovative medical device as they are treated for breast cancer at Southlake.

“As a clinician caring for women with cancer in our community, I’m incredibly proud of the work Southlake is doing to advance women’s health and improve patient experiences,” said Sara Temple, MD, Surgical Oncologist and Chief of Surgery at Southlake. “Women who visit Southlake can be confident that they are receiving leading edge care, close to home when they need it most.”

The World Health Organization anticipates a 77 per cent increase in cancer diagnoses by 2050.  Southlake serves some of the fastest growing communities in Canada and anticipates that the number of patients requiring cancer care will grow. By investing in new technology, Southlake is ensuring that women in the communities it serves have access to leading edge cancer care. All of these investments were funded with support from community donors who generously gave to Southlake to support investments into women’s health at the hospital.

“The generosity of our donor community and the impact they have made for women receiving cancer diagnosis and treatment at Southlake is something we can all take great pride in,” said Jennifer Ritter, President and CEO of Southlake Foundation. “From our Women’s Health Initiative donors supporting new mammography machines, to the Ladies in Philanthropy for Southlake funding the MOLLI 2 System, to our long-standing partners The Edge Benefits and Pheasant Run Golf Club enabling the introduction of MyoSure System through their joint annual charity golf tournament, we are incredibly lucky to share a vision of access to exceptional care for everyone who depends on Southlake when they need us most. Thank you, to every donor who contributed to these important upgrades to care for women.”

Southlake Foundation’s HERE is Where Cancer Meets its Match campaign supports the Stronach Regional Cancer Centre at Southlake. For more information or to make a donation, visit: southlake.ca/HERE.

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Pasteurized milk includes remnants of H5N1 bird flu, U.S. officials say

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The U.S. Food and Drug Administration says that samples of pasteurized milk have tested positive for remnants of the bird flu virus that has infected dairy cows.

The agency stressed that the material is inactivated and that the findings “do not represent actual virus that may be a risk to consumers.” Officials added that they’re continuing to study the issue.

“To date, we have seen nothing that would change our assessment that the commercial milk supply is safe,” the FDA said in a statement on Tuesday.

The announcement comes nearly a month after an avian influenza virus that has sickened millions of wild and commercial birds in recent years was detected in dairy cows in at least eight states. The Agriculture Department (USDA) says 33 herds have been affected to date.

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FDA officials didn’t indicate how many samples they tested or where they were obtained. The agency has been evaluating milk during processing and from grocery stores, officials said. Results of additional tests are expected in “the next few days to weeks.”

WATCH | Bird flu spread in U.S. cows:

 

Bird flu is spreading in cows. Are humans at risk? | About That

15 days ago

Duration 8:54

For the first time ever, avian influenza, or H5N1 bird flu, was detected in roughly a dozen dairy cow herds across the U.S. About That producer Lauren Bird explores why scientists and public health officials are concerned about the cross-species transmission and whether humans are now at higher risk.

The polymerase chain reaction (PCR) lab test the FDA used would have detected viral genetic material even after live virus was killed by pasteurization, or heat treatment, said Lee-Ann Jaykus, an emeritus food microbiologist and virologist at North Carolina State University

“There is no evidence to date that this is infectious virus, and the FDA is following up on that,” Jaykus said.

Officials with the FDA and the USDA had previously said milk from affected cattle did not enter the commercial supply. Milk from sick animals is supposed to be diverted and destroyed. Federal regulations require milk that enters interstate commerce to be pasteurized.

Tests for viable virus underway, agency says

Because the detection of the bird flu virus known as Type A H5N1 in dairy cattle is new and the situation is evolving, no studies on the effects of pasteurization on the virus have been completed, FDA officials said. But past research shows that pasteurization is “very likely” to inactivate heat-sensitive viruses like H5N1, the agency added.

The agency said it has been evaluating milk from affected animals, in the processing system and on the shelves. It said it is completing a large, representative national sample to understand the extent of the findings.

The FDA said it is further assessing any positive findings through egg inoculation tests, which it described as a gold standard for determining viable virus.

Matt Herrick, a spokesperson for the International Dairy Foods Association, said that time and temperature regulations for pasteurization ensure that the commercial U.S. milk supply is safe. Remnants of the virus “have zero impact on human health,” he wrote in an email.

Scientists confirmed the H5N1 virus in dairy cows in March after weeks of reports that cows in Texas were suffering from a mysterious malady. The cows were lethargic and saw a dramatic reduction in milk production. Although the H5N1 virus is lethal to commercial poultry, most infected cattle seem to recover within two weeks, experts said.

To date, two people in the U.S. have been infected with bird flu. A Texas dairy worker who was in close contact with an infected cow recently developed a mild eye infection and has recovered. In 2022, a prison inmate in a work program caught it while killing infected birds at a Colorado poultry farm. His only symptom was fatigue, and he recovered.


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Remnants of bird flu virus found in pasteurized milk, FDA says

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The U.S. Food and Drug Administration said Tuesday that samples of pasteurized milk had tested positive for remnants of the bird flu virus that has infected dairy cows.

The agency stressed that the material is inactivated and that the findings “do not represent actual virus that may be a risk to consumers.” Officials added that they’re continuing to study the issue.

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