Q&A: Mosquito breeding trial raises hopes of defeating dengue
Public health messaging for dengue control often encourages the clean-up of mosquito breeding sites. But a novel method that researchers at the World Mosquito Program have introduced to several communities over the past eight years directly counters that concept. Instead of killing mosquitoes, they breed mosquitoes injected with Wolbachia bacteria and release them to communities that have been affected by dengue. Evidence from different countries where the method has been used showed large reductions in dengue transmissions. The method is not about suppressing the mosquito population, but about transforming them to a population that carries Wolbachia. So it’s novel.
Polio case reported in Malaysia – first in 27 years
A polio case has been confirmed in the country, the first in Malaysia in 27 years. Health director-general Datuk Dr Noor Hisham Abdullah said the last polio case in Malaysia occurred in 1992, and in 2000, the country was declared as being polio-free. In the recent case, the child was confirmed to be infected with the vaccine-derived poliovirus type 1 (VDPV1) on Dec 6 this year. He added that the VDPV1 is classified as a circulating vaccine-derived poliovirus (cVDPV) type 1. "Those who have been vaccinated will be protected from infection." Dr Noor Hisham said test results showed that the virus has genetic links to the polio virus that was detected in a recent outbreak in the Philippines. Investigations at the vicinity of the polio-infected child's residence found that 23 out of 199 people aged between two months until 15 years there have not received the polio vaccine. "This is a frustrating situation because the circulation of a cVDPV can only end with a polio immunisation. "After explaining the importance of polio immunisation, the parents of the children have agreed to have them vaccinated," he said.
Global heating driving spread of mosquito-borne dengue fever
Rising temperatures across Asia and the Americas have contributed to multiple severe outbreaks of dengue fever globally over the past six months, making 2019 the worst year on record for the disease. In 1970 only nine countries faced severe dengue outbreaks. But the disease, which is spread by mosquitoes that can only survive in warm temperatures, is now seen in more than 100 countries.There are thought to be 390 million infections each year. As climate change alters monsoon and rain patterns in many countries, this creates the damp and warm conditions that, along with rapid urbanisation, help the Aedes mosquitoes flourish. Asian countries, including Bangladesh, Thailand, Cambodia and Laos, also had outbreaks, with a particularly severe situation in the Philippines, where 1,000 people died of the disease, including hundreds of children.
An Aussie doctor in Samoa has labelled the measles outbreak an 'extraordinary crisis'
The leader of Australia’s emergency medical response team in Samoa has labelled the measles outbreak as an “extraordinary crisis” as the Pacific Island nation grapples with 249 new recorded cases in the last 24 hours alone. Fiji and Tonga have also been hit by the outbreak, believed to have originated in New Zealand, but Samoa has been worst affected because of vaccination rates as low at 25-48 per cent, according to the World Health Organisation. Emergency doctor Mark Little is the Mission leader for the Australian Medical Assistance Teams (AUSMAT) -- a disaster response team deployed by the Department of Foreign Affairs.
The 2019 report of The Lancet Countdown on health and climate change: ensuring that the health of a child born today is not defined by a changing climate
Nick Watts, MA et al.,
The Lancet Countdown is an international, multidisciplinary collaboration, dedicated to monitoring the evolving health profile of climate change, and providing an independent assessment of the delivery of commitments made by governments worldwide under the Paris Agreement. A child born today will experience a world that is more than four degrees warmer than the pre-industrial average, with climate change impacting human health from infancy and adolescence to adulthood and old age. Across the world, children are among the worst affected by climate change. Downward trends in global yield potential for all major crops tracked since 1960 threaten food production and food security, with infants often the worst affected by the potentially permanent effects of undernutrition (indicator 1.5.1). Children are among the most susceptible to diarrhoeal disease and experience the most severe effects of dengue fever. Trends in climate suitability for disease transmission are particularly concerning, with 9 of the 10 most suitable years for the transmission of dengue fever on record occurring since 2000 (indicator 1.4.1). Similarly, since an early 1980s baseline, the number of days suitable for Vibrio (a pathogen responsible for part of the burden of diarrhoeal disease) has doubled, and global suitability for coastal Vibrio cholerae has increased by 9·9% (indicator 1.4.1).
Mosquito sterilization offers new opportunity to control chikungunya, dengue, and Zika
The Sterile Insect Technique (SIT) is a form of insect birth control. The process involves rearing large quantities of sterilized male mosquitoes in dedicated facilities, and then releasing them to mate with females in the wild. As they do not produce any offspring, the insect population declines over time. “Half the world’s population is now at risk of dengue,” said Dr Soumya Swaminathan, WHO Chief Scientist. “And despite our best efforts, current efforts to control it are falling short. We desperately need new approaches and this initiative is both promising and exciting.” In recent decades, the incidence of dengue has increased dramatically due to environmental changes, unregulated urbanization, transport and travel, and insufficient sustainable vector control tools and their application.
Dengue fever cases rise, claiming 74 lives in Laos
Lao health authorities are advising people across the country to clear out potential mosquito breeding sites after dengue fever claimed 74 lives and more than 37,700 people have contracted the virus so far this year. The warning comes this week after more cases of dengue fever have been detected with most of the infections and deaths recorded in the capital Vientiane and the southern provinces of Laos, local daily Vientiane Times reported on Thursday. Director General of Lao National Center for Laboratory and Epidemiology, Department of Communicable Disease Control, Onechanh Keosavanh, outlined authorities' concerns and measures to control and prevent dengue. Meanwhile, improvement of the diagnosis and treatment of dengue at provincial and district hospitals and dispensaries is essential to prevent unavoidable deaths, he said. "If you fall ill at this time of the year, you should consider the fact that dengue could be the likely cause. Please go to a hospital for a diagnosis as quickly as possible. Don't try to buy medicine at a pharmacy and take it at home," he advised.
Scientists move closer towards developing an effective malaria vaccine
Professor Denise Doolan from James Cook University’s Australian Institute of Tropical Health and Medicine (AITHM) was part of an international team that narrowed down the malaria proteins and disease-fighting antibodies that could be used to develop a vaccine against severe malaria. “It’s the first time anyone has shown this – for years, researchers have thought that developing a malaria vaccine based on PfEMP1 would be virtually impossible, because the proteins are just so diverse,” Associate Professor Barry said. The team of collaborators – involving JCU, the Walter and Eliza Hall Institute of Medical Research (WEHI) at Deakin University, and malaria experts from Papua New Guinea, France and the USA – collected hundreds of PfEMP1 proteins from malaria strains from children in PNG who had been naturally infected by the disease, made a custom protein microarray of those strains, and then examined serum samples to identify which of the many PfEMP1 variants were associated with protection. The research team managed to pinpoint which antibodies were most effective in fighting the most severe forms of malaria.
Inoculating against the spread of viral misinformation
The role of social media in giving a platform to unscientific anti-vaccine messages and organizations has become a flashpoint. Research calls attention to the threat of social media misinformation as it may contribute to increasing "vaccine hesitancy," which the World Health Organization ranks among the top threats to global health this year. This increasing reluctance or refusal to vaccinate threatens to reverse the progress made in halting vaccine-preventable diseases, such as measles, which has seen a 30% increase in cases globally. The research team, co-led by UMD's Dr. Sandra C. Quinn, GW's Dr. David Broniatowski and JHU's Dr. Mark Dredze, examined more than 500 vaccine-related ads served to Facebook users and archived in Facebook's Ad Library. This archive, which became available in late 2018, catalogued ad content related to "issues of national importance." Their findings reveal that the majority of advertisements (54%) which opposed vaccination, were posted by only two groups funded by private individuals, the World Mercury Project and Stop Mandatory Vaccination, and emphasized the purported harms of vaccination.
Optimising systemic insecticide use to improve malaria control
Hannah R Meredith et al.,
The review identified drugs from four classes commonly used in livestock and companion animals: avermectins, milbemycins, isoxazolines and spinosyns. Simulations predicted that isoxazolines and spinosyns are promising candidates for mass drug administration, as they were predicted to need less frequent application than avermectins and milbemycins to maintain mosquitocidal blood concentrations.
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