A Measles Death, Vaccines, and the Media's Failure to Inform
Learning English
IntroductionEvery year, mosquito-borne diseases kill around three-quarters of a million globally. But could it get worse with climate change? With warming temperatures, mosquitos are now spreading to new areas, including Europe. We'll hear about dengue fever, one of the diseases they bring, and teach you related vocabulary.
This week's questionDengue isn't the only sickness mosquitos spread, so which of the following is also a mosquito-borne disease?
a) ebola
b) cholera
c) malaria
Listen to the programme to find out the answer.
Vocabularysymptomphysical signs of the presence of an illness or disease in your body
fevermedical condition in which your body temperature is higher than normal, and your heart beats very fast
critical windowlimited period of time during which action must be taken to achieve a desired result
hostplant or animal that another plant or animal lives on as a parasite, or uses for food
a part of the jigsaw/puzzlea part of a complicated or continuing situation that helps you to understand it
domino effectsituation in which something, usually bad, happens, causing further negative events to happen
TRANSCRIPTNote: This is not a word-for-word transcript.
BethHello. This is 6 Minute English from BBC Learning English. I'm Beth.
NeilAnd I'm Neil.
BethHere at 6 Minute English, we discussed animals adapting their behaviour in response to climate change in earlier programmes, but we didn't focus on one species in detail. So, in this programme, we'll take a look at an especially unwelcome insect: the mosquito.
NeilEvery year, mosquito-borne diseases kill around three-quarters of a million globally, with most deaths occurring in children under five.
BethWith warming temperatures, mosquitos are now spreading to new areas, including Europe. We'll hear about dengue fever, one of the diseases they bring, and as usual, we'll learn some useful new vocabulary as well. But first, I have a question for you, Neil. Dengue isn't the only sickness mosquitos spread, so which of the following is also a mosquito-borne disease? Is it:
a) ebola,
b) cholera, or
c) malaria?
NeilI think the answer is c) malaria.
BethOK, Neil, we'll find out later in the programme. One country at the forefront of the problem is Indonesia which, in recent years, has seen a surge in dengue-related deaths. Here's Dr. Dewi Iriani, a paediatrician in the Indonesian capital, Jakarta, speaking with BBC World Service programme, The Climate Question.
Dr. Dewi IrianiFever and muscle aches are common symptoms for a viral infection. But if they're accompanied by symptoms, for example red spots on the skin, or maybe there is a fever that lasts for three days, we can suspect that it's dengue fever. Day five to seven is the critical window for a dengue fever patient. Sometimes parents don't know about this critical window, and when they bring the child to the hospital, it's difficult for us to help.
NeilDr. Iriani describes the symptoms of dengue – the signs that indicate the presence of a disease in your body. These include fever, when your body temperature is higher than normal, and your heart beats very fast.
BethDengue is not fatal - if you receive treatment quickly. There is a critical window between days five and seven of the infection when a patient needs treatment to survive. A critical window refers to a limited period of time during which action must be taken to achieve a certain result.
NeilDengue cases in Indonesia have now grown to over 150,000 and many blame climate change. Periods of drought, when little rain falls, force people to collect drinking water in buckets, giving mosquitos places to breed.
BethAccording to Professor Manisha Kulkarni, an epidemiologist from the University of Ottawa, higher temperatures also mean higher rates of replication, something she explained to Paul Conolly, presenter of BBC World Service's, The Climate Question.
Manisha KulkarniThe higher the temperature, the quicker that the mosquito can actually replicate that virus within its body, and then be able to transmit it back to another host when it bites.
Paul ConollyManisha also talked about the link between poverty and dengue, which is an important part of this jigsaw isn't it, because as more and more people move to cities and live in cramped conditions, with poor sanitation, then more and more people are exposed to dengue, so there's something of a domino effect here.
NeilDengue spreads when an infected mosquito bites a host – an animal that another animal lives on or uses for food. And Professor Kulkarni is concerned about poverty as much as climate change. She calls it an important part of the jigsaw, an idiom meaning a part of a complicated situation that helps you understand it.
BethPoverty forces many Indonesians to move into crowded cities with poor sanitation. These provide the perfect breeding ground for mosquitos creating a domino effect - a situation in which something bad happens, causing further negative consequences.
NeilThe domino effect means that dengue is spreading not just in Asia, but in parts of the world which didn't have it before, including France, Spain, and Italy. But the news isn't all bad. Fortunately, technology is getting better at slowing the spread, including early warning systems that can predict dengue outbreaks months in advance, and the ongoing work to produce a vaccine. All of which, hopefully, mean an end to dengue, and similar diseases… speaking of which, Beth, what was the answer to your question?
BethI asked you to name another mosquito-borne disease, besides dengue.
NeilAnd I said malaria.
BethWhich was the correct answer! Dengue, malaria, and yellow fever are all diseases spread by mosquitoes. Right, let's recap the vocabulary we've learned from this programme, starting with symptom – a sign of the presence of a disease in your body.
Neil
A fever is a medical condition which increases your body temperature and heartbeat.
BethA critical window is a limited period of time during which action must be taken to achieve the desired outcome.
NeilThe word host has several meanings, but in biology it's a plant or animal that another plant or animal lives on as a parasite or uses for food.
BethThe idiom part of the jigsaw,or part of the puzzle, means a part of a complicated situation that helps you to understand it.
NeilAnd finally, one negative event causing another, which in turn causes another, can be called a domino effect. Once again, our six minutes are up. Goodbye!
BethBye!
What Mosquitoes Are Most Attracted To In Human Body Odor Is Revealed
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Anyone who has spent a summer evening swatting away mosquitoes, or a summer day scratching mosquito bites, can agree: Mosquitoes stink. But the smells produced by humans are an important part of what draws mosquitoes to us.
In a scientific report published Friday, scientists helped pinpoint the different chemicals in body odor that attract these insects by building an ice-rink size testing arena and pumping in the scents of different people.
Mosquitoes are part of the fly family, and most of the time, they feed on nectar. However, females preparing to produce eggs need a meal with extra protein: blood.
Best-case scenario, getting bitten will just leave you with an itchy red bump. But mosquito bites often turn deadly, thanks to parasites and viruses the insects transmit. One of the most dangerous of these diseases is malaria.
Malaria is a blood-borne disease caused by microscopic parasites that take up residence in red blood cells. When a mosquito bites a person infected with malaria, it sucks up the parasite along with the blood. After developing in the mosquito's stomach, the parasite "will migrate to the salivary glands and then be spat back out into the skin of another human host when the mosquito blood-feeds again," said Dr. Conor McMeniman, an assistant professor of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health and Johns Hopkins Malaria Research Institute in Baltimore.
Malaria has been eradicated in the United States in the past century thanks to window screens, air conditioning and improvements to drainage systems where mosquitoes' aquatic larvae can grow, but the disease remains a danger to much of the world.
"Malaria still accounts for more than 600,000 deaths per year, mostly in children under the age of 5 years, and also pregnant women," said McMeniman, the senior author of the new study published in the journal Current Biology.
Genetically modified mosquitoes bred to fight Zika
"It inflicts a lot of suffering around the world, and part of the motivation for this study was to try and really understand how mosquitoes that transmit malaria are finding humans."
McMeniman, along with Bloomberg postdoctoral researchers and the study's first authors, Drs. Diego Giraldo and Stephanie Rankin-Turner, focused on Anopheles gambiae, a species of mosquito found in sub-Saharan Africa. They partnered with Zambia's Macha Research Trust, led by scientific director Dr. Edgar Simulundu.
"We were really motivated to try and develop a system where we could study the behavior of the African malaria mosquito in a naturalistic habitat, reflective of its native home in Africa," McMeniman said. The researchers also wanted to compare the mosquitoes' smell preferences across different humans, to observe the insects' ability to track scents across distances of 66 feet (20 meters), and to study them during their most active hours, between 10 p.M. And 2 a.M.
To tick all these boxes, the researchers created a screened facility the size of a skating rink. Dotting the perimeter of the facility were six screened tents where study participants would sleep. Air from their tents, carrying the participants' unique breath and body odor scents, was pumped through long tubes to the main facility onto absorbent pads, warmed and baited with carbon dioxide to mimic a sleeping human.
Hundreds of mosquitoes in the main 20-by-20-meter facility were then treated to a buffet of the sleeping subjects' scents. Infrared cameras tracked the mosquitoes' movement to the different samples. (The mosquitoes used in the study were not infected with malaria, and they couldn't reach the sleeping humans.)
The researchers found what many who have been on a picnic would attest to: Some people attract more mosquitoes than others. What's more, chemical analyses of air from the tents revealed the odor-causing substances behind the mosquitoes' attraction, or lack thereof.
The mosquitoes were most attracted to airborne carboxylic acids, including butyric acid, a compound present in "stinky" cheeses such as Limburger. These carboxylic acids are produced by bacteria on human skin and tend not to be noticeable to us.
While carboxylic acids attracted the mosquitoes, the insects seemed to be deterred by another chemical called eucalyptol, which is present in plants. The researchers suspected that one sample with a high eucalyptol concentration might have been related to the diet of one of the participants.
Simulundu said that finding a correlation between the chemicals present in different people's body odor and the mosquitoes' attraction to those scents was "very interesting and exciting."
"This finding opens up approaches for developing lures or repellents that can be used in traps to disrupt the host-seeking behavior of mosquitoes, thereby controlling malaria vectors in regions where the disease is endemic," said Simulundu, a coauthor of the study.
Dr. Leslie Vosshall, a neurobiologist and vice president and chief scientific officer of the Howard Hughes Medical Institute who was not involved with the study, was similarly enthusiastic. "I think it's a super exciting study," she said. "It's the first time that an experiment of this type has been done at this scale outside the lab."
Vosshall researches another mosquito species that spreads dengue fever, Zika and Chikungunya. In a study published last year in the journal Cell, she and her colleagues found that this mosquito species also seeks out the scent of carboxylic acids produced by bacteria on human skin. The fact that these two different species respond to similar chemical cues is a good thing, she said, because that could make it easier to create repellents or traps for mosquitoes across the board.
The research might not have any immediate implications for avoiding bug bites at your next barbecue. (Vosshall said that even scrubbing with unscented soap doesn't get rid of the natural scents that attract mosquitoes.) However, she noted that the new paper "gives us some really good clues about what mosquitoes are using to hunt us, and understanding what that is, is essential for us to come up with the next steps."
Kate Golembiewski is a freelance science writer based in Chicago who geeks out about zoology, thermodynamics and death. She hosts the comedy talk show "A Scientist Walks Into a Bar."
How To End Malaria
We think of malaria as a problem faced only by humid, hot countries. But just over a century ago, the disease thrived as far north as Siberia and the Arctic Circle and was endemic in 36 states of the US.
We don't have specific data that far back for Egypt, but back then malaria is estimated to have killed 2.5 million people each year in the Middle East, South Asia, and Western Pacific.
Much of the developed world eliminated malaria in the 1950s through an increase in prosperity, housing, and breakthroughs in medication and insecticides. As people became wealthier, mosquito breeding ground marshes were drained, and an increase in livestock meant mosquitos had animals to bite instead of humans.
Improved nutrition made people healthier and less vulnerable, while increased incomes afforded better homes and insect screens. Quinine and then synthetic chloroquine gave the developed countries affordable treatment, and insecticides wiped out many mosquito populations.
Outside of Sub-Saharan Africa, annual deaths from malaria plummeted from more than three million in 1930 to fewer than 30,000 today. Yet, much of the malaria problem has stubbornly remained in Africa, where it kills more than half a million people every year.
There are two key reasons. First, the malaria parasite found in Africa is the deadliest, and strains have developed resistance to the common medicine chloroquine. Second, the prevalent malaria-spreading mosquitos in Africa almost exclusively bite humans. There was progress against malaria in Africa at the start of the 2000s, but that was halted by Covid-19, which disrupted basic medicine and caused around 60,000 more deaths.
The world has long promised to get rid of malaria for good. The Global Malaria Eradication Programme was established in 1955, then abandoned in 1969 because the goal was deemed unachievable. In 2015, world leaders renewed the pledge. In the UN's current global promises known as the Sustainable Development Goals (SDGs), all nations have undertaken to fix almost every global problem by 2030, including malaria.
Progress has been glacial, which means the malaria goal will be achieved some 400 years late. This is just one of many spectacular failures of the big UN promises. This is because the politicians promised too much. The global priorities include an impossible 169 promises, which is indistinguishable from having no priorities at all.
This year, the world will be at halftime for its 2030 promises, yet it will be nowhere near halfway. It is time to identify and prioritise the most crucial goals. My think tank, the Copenhagen Consensus, is doing exactly that: together with several Nobel laureates and more than 100 leading economists, we have been working for years to identify where each dollar, rupee, or shilling can do the most good.
Our new research on malaria, written by Rima Shretta and Randolph Ngwafor at the University of Oxford, proposes a 10 per cent scale-up in the use of bed nets in the 29 highest-burden countries in Africa alongside insecticide-resistance management strategies between now and the end of the UN's 2030 promises.
Ensuring people sleep under an insecticide-treated bed net is one of the most effective ways to prevent malaria. Mosquitos are blocked by the netting and killed by the insecticide. Bed nets each cost less than $4, yet result in a dramatic reduction in transmission by ensuring the mosquitos die before the malaria parasites can mature and spread.
It is important that bed nets are not just distributed but actually used correctly, which requires social behaviour changes and communication and information-sharing. Even allowing for this, and for the higher price tag of responding to resistant strains of malaria, the cost across this decade is about $1.1 billion a year.
To put this into context, that is one-third of what the US population spends on lipstick each year.
This investment will save 30,000 lives even in 2023. By the end of the decade, the number of malaria deaths will be halved, saving some 1.3 million lives in total.
Bed nets also mean many fewer infections with malaria. The research shows that 242 million fewer people will get sick in 2030, drastically reducing healthcare costs. Moreover, reducing the number of sick people means adults can go to work, children can go to school, and caregivers are not stretched, which at a country level increases productivity.
Putting all these factors together, every dollar spent on this campaign would yield societal benefits worth $48, a phenomenal return on investment.
We have allowed malaria to turn into a disease of poverty in Africa. And while we cannot deliver on all the global UN promises, we ought to deliver on the smartest things first. Distributing and using insecticide-treated bed nets will cost little but save 1.3 million lives.
The writer is president of the Copenhagen Consensus and a visiting fellow at Stanford University's Hoover Institution.
A version of this article appears in print in the 11 May, 2023 edition of Al-Ahram Weekly.
* Click here to read the story in arabic.
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