As the impacts of climate change escalate, ecosystems will likely undergo events that will disrupt entire populations. In marine ecosystems, anthropogenic warming has subjected organisms to elevated temperatures, oxygen loss, and acidification. The increased frequency and severity of catastrophic events may inhibit a population’s ability to recover and, in turn, may spur collapse.

Overexploitation and population collapse pose significant threats to marine fish stocks across the globe. While certain fish populations have already collapsed, research indicates that nearly one third of fisheries worldwide are currently impacted by overharvesting.

In 2017, malaria killed 435 000 people around the world. The vast majority of these deaths – 403 000 – were on the African continent. Most malaria cases are in sub-Saharan Africa.

My colleagues and I at the National Institute for Communicable Diseases track malaria cases and mosquito behaviour in South Africa.

As part of our research we have looked at three key aspects. One is the effect of human activity on mosquito biology. Here we looked at the effects of heavy metal pollution on various life history traits as well as the expression of insecticide resistance in Anopheles arabiensis, which is one of the mosquito species that transmits malaria.

We also did research into what impact changes in climate are having on the efficacy of insecticides aimed at malaria vectors.

And, finally, we looked at what the effect of higher temperatures is on the major malaria vector, An. arabiensis.

An. arabiensis is extremely difficult to control. Besides already reported insecticide resistance, they are prone to avoiding insecticide treated nets and walls. These mosquitoes also tend to bite people outdoors, where little can be done for protection.

Our work aims to understand the biology of this complex mosquito to track how changes in the environment are affecting the behaviour of this animal. This will hopefully inform malaria control strategies and bring us closer to eliminating the disease.

Toxins

The larval stage of the mosquito is aquatic. This vulnerable stage is crucial for the well-being of adult mosquitoes, in the same way that the health of a human baby will determine an adult’s future health.

Many larval environmental factors have a profound effect on the well-being of the adult mosquito. These include the environmental temperature, the level of crowding and access to nutrition. Human activity, however, has resulted in increased levels of water pollution, and mosquito larvae being exposed to more toxins.

This has a big impact on malaria transmitting mosquitoes. These insects usually breed in clean water, but have adapted to breeding in polluted water. This means that malaria vectors can now potentially increase their range to areas where malaria didn’t usually occur.

Our research shows that polluted water sources are becoming a breeding ground for mosquitoes that are tolerant to a range of toxins. We found that adult mosquitoes that were exposed to metal during the larval stage developed insecticide resistance.

Currently we do not know whether insecticide-resistant or susceptible mosquitoes are better at transmitting malaria. But polluting activities are resulting in range expansion and changes in selection procedures in mosquitoes.

Temperature on insecticides and mosquitoes

Further research we did suggests that high temperatures also affect the efficacy of certain insecticides.

Insecticides are commonly used as public health interventions against malaria vectors in some African countries including South Africa, Cameroon and Kenya. They are an important part of malaria control policies and strategies to eliminate the disease.

Our findings are important in efforts to determine the efficacy of insecticides currently used. But our study was based in a laboratory under controlled conditions, so our findings must still be tested in a real-life setting. This is because different temperatures could have different effects. Environmental conditions also vary and could have an impact on the efficacy of insecticides.

When it comes to mosquitoes, our research showed that temperature can have a significant impact on the life cycle of these insects. For example, climate change may affect the distribution of malaria vectors. We studied how rising temperatures affected major malaria vectors. We focused specifically on how insecticide-resistant vectors were affected versus vectors that are susceptible to insecticide.

Mosquitoes that develop resistance are more tolerant of high temperatures than those that aren’t resistant. This means that as temperatures rise, so do the survival odds of insecticide-resistant mosquitoes. This will complicate malaria control.

Why we should be worried

Human activities are driving mosquito evolution. Polluting activities are resulting in malaria-transmitting mosquitoes expanding into regions where they previous weren’t. Adaptation to water pollution results in increased tolerance to pesticides.

Insecticide resistant or tolerant mosquitoes cope better with more toxic pollutants. Currently it is not known if these mosquitoes are more likely transmit malaria than insecticide susceptible mosquitoes.

Scientists are only beginning to unravel what this could mean for the elimination of malaria.

Shüné Oliver, medical scientist , National Institute for Communicable Diseases

This article is republished from The Conversation under a Creative Commons license. Read the original article.

^{Image credit: Supplied/The Conversation}

Shüné Oliver, National Institute for Communicable Diseases

Millions of Americans work shifts, and new research suggests it’s doing their cardiovascular health no favours.

The Chinese study of more than 320 000 people found that shift workers are at heightened risk for heart disease, and the more years they work shifts, the greater their risk.

Disruption of normal sleep-wake cycle

Shift work “can earn more profit, but it can also cause harm to the health of employees, so employers should reduce shift work as much as possible,” advised study lead author Dr Weihong Chen. She’s a researcher in occupational and environmental health at Huazhong University of Science and Technology in Wuhan.

In the study, Chen’s team analysed data from 21 prior studies involving hundreds of thousands of people and nearly 20 000 cases of coronary heart disease, which is caused by blocked blood flow in the heart.

The study wasn’t designed to prove cause and effect, but the data showed that shift workers were 13% more likely to develop coronary heart disease than daytime workers.

And for every year spent working on shift work, there was a nearly 1% increase in the risk of coronary heart disease, Chen and colleagues reported in the journal Occupational Medicine.

The reason why shift workers are at increased risk for coronary heart disease isn’t known, but disruption of the normal sleep-wake cycle, increased stress, and unhealthy lifestyles often associated with shift work could be factors, the Chinese team reasoned.

Heart disease is a major killer, however, so there are big implications for millions of workers.

Additional risk factor

“The number of deaths due to ischaemic heart disease has continued to rise with 7.6 million deaths in 2005 and 8.9 million people dying due to the condition in 2015,” Chen said in a journal news release. “Patients can require surgical interventions and medications, meaning ischaemic heart disease is one of the biggest burdens on health care systems.”

Dr Satjit Bhusri, a cardiologist at Lenox Hill Hospital in New York City, agreed.

Reviewing the new findings, Bhusri said that “physicians and patients should both take this occupational situation as an additional risk factor for heart disease, and initiate prevention and treatment early.”

How might that work, exactly? According to Chen, “employers should pay attention to staff members who are experiencing symptoms of heart problems, as well as those with a family history of heart disease. Employers could provide health promotion, such as information on how to prevent and deal with ischaemic heart disease.”

Finally, she said, “companies could also consider providing health checks to detect early signs of heart problems.”

^{Image credit: iStock}

Every death from malaria is a tragedy. But many infections can be prevented. This is particularly true for holidaymakers, travellers, or people visiting their families in malaria endemic areas. All they need to do is follow some very simple rules. Malaria is a complicated disease – I should know, after studying it for more than 30 years – but the solutions to avoiding and treating it can be as simple as “ABCD”. If the basics of prevention are followed, a great deal of unnecessary illness and mortality can be avoided.

Avoidance to detection

A is for Awareness and Avoidance of malaria risk

Several factors influence your chance of getting malaria in a particular area. Understanding these can help you to avoid or least minimise the risk.

The first question to ask is: how much malaria normally occurs in the area, and when? The answer will depend on altitude and climate – generally the lower, warmer and more humid the place, the more suitable it is for malaria vectors, the Anopheles mosquitoes.

In southern Africa, most malaria is seasonal. It increases during warmer and wetter summer months (September to May in the southern hemisphere). The risk in winter is generally lower, but that doesn’t mean it’s absent.

Longer exposure, involving overnight stays, puts you at higher risk than brief visits, for example day trips to game reserves. Hiking and camping outdoors is riskier than staying in air-conditioned accommodation.

Some people are at higher risk for severe malaria and should ideally avoid malaria transmission areas altogether. These include pregnant women, babies and young children, people who’ve had their spleens removed and those with weak immune systems.

B is for mosquito bites – and avoiding them

Avoiding mosquito bites is the most important preventive measure. This is because the mosquito bite is what transmits the parasite. No bite, no transmission.

Contact between mosquitoes and people isn’t random. Mosquitoes actively seek people out. They have sensory organs that detect people’s warmth, exhaled carbon dioxide, and odours from sweat.

There are a number of ways to avoid mosquito bites. These include staying indoors between dusk and dawn and covering up bare skin when outside at night. (Mosquitoes find ankles particularly attractive.)

There are also a number of repellents and insecticides that can deter mosquitoes. Repellents should be applied to bare skin, and clothes can be treated. Other ways to avoid being bitten include burning mosquito coils or using heated insecticide mats in living and sleeping areas at night, and using insecticide-treated mosquito nets.

Using ceiling fans and air conditioners discourages mosquito activity indoors, likewise making sure screens on windows are closed and in good condition. Just because you don’t hear mosquitoes buzzing around doesn’t mean you are safe – the malaria mosquitoes fly silently.

C is for Chemoprophylaxis and Compliance

You should consult a health care practitioner with travel medicine experience well before travelling to an endemic malaria area. During this consultation, you can figure out whether you need chemoprophylaxis (medication to prevent infection) in addition to personal protection measures.

Several factors will influence this decision. These include the risk of contracting malaria (the area and type of accommodation, time of year, and duration of visit); personal factors such as age, current medication and existing illness; and medication options, their availability and price, adverse effects and resistance.

There are two type of medications used for malaria prophylaxis, they act at different life stages of the parasite in the body. Atovaquone-proguanil products stop infection early, soon after the mosquito bite. The second type (doxycycline, mefloquine and atovaquone-proguanil) treat a later stage of infection, but before the parasites can multiply enough to cause symptoms.

Whichever medication your doctor recommends, if any, it’s important to take it exactly as directed and to finish the course.

There’s a dangerous myth that chemoprophylaxis “masks” symptoms and makes malaria more difficult to diagnose. Prophylactic medications are highly effective if taken properly. But the infection may

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take longer to show if compliance is poor and doses are missed or prematurely stopped. It’s important to understand that no prophylactic regimen is 100% effective – but infection is still likely to be milder than if no prophylaxis was used.

D is for Detection

Sometimes precautions can’t protect you entirely. That’s when it becomes important to diagnose malaria as early as possible. If you get ill with flu-like symptoms such as headache, fever, chills, joint and muscle pains up to three months after returning from a malaria area, be sure to mention this to your health care providers.

A single negative test doesn’t rule out malaria, and tests should be repeated until either malaria is confirmed, or an alternative diagnosis is made. Occasionally, malaria is transmitted outside endemic areas by mosquitoes that have hitched rides in cars or taxis, and because there’s no travel history to alert doctors to the possibility of malaria, the diagnosis is often delayed, sometimes with fatal consequences. One clue to malaria here is a low platelet count. This is often picked up accidentally when tests are being done for a feverish illness with no obvious cause.

To wrap it up

A number of steps are key to ensuring a quick recovery. These are: reporting the illness early after travelling in a malaria area; prompt diagnosis; and, finally, early and effective treatment.

If any of these steps are delayed the chances of developing severe and complicated malaria are much higher – and the rate of survival substantially lower.

John Frean, Principal Pathologist, Centre for Emerging, Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases and Wits Research Institute for Malaria, University of the Witwatersrand

This article is republished from The Conversation under a Creative Commons license. Read the original article.

^{Image credit: iStock}

John Frean, Principal Pathologist, Centre for Emerging, Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases and Wits Research Institute for Malaria, University of the Witwatersrand

Jilly Moss’s daughter Alba spent eight days in a London hospital after contracting the viral illness.

A woman in the United Arab Emirates regained consciousness after spending 27 years in a minimally responsive state, according to UAE-based news service The Nation.

The woman, Munira Abdulla, was involved in a car accident with her son in 1991. She was comatose after the accident and later became minimally responsive—and she stayed that way until June of last year.

In June, she started speaking again for the first time since the accident. Her son says she's now able to have entire conversations.

After hearing Abdulla's story, we had questions. The first was: How did this happen? So we asked an expert for the facts.

RELATED: A Measles Complication Has Left an Israeli Flight Attendant in a Coma for 10 Days—Here's Why

"The unusual part of this case is that the delay was so long," Vivien Lee, MD, director of the Comprehensive Stroke Center at the Ohio State University Wexner Medical Center, tells Health.

It's extremely rare for someone to recover consciousness after so long, she says. "It is possible for somebody to maybe get better after years. These cases are rare, but it's possible."

Abdulla's son, Omar Webair, was 4 at the time of the accident, which happened when a school bus collided with the car he and his mother were in. Webair told The Nation his mother shielded him from the impact of the crash. He walked away from the crash with a minor injury, but his mother wasn't as fortunate.

Dr. Lee says one of three things happens when a patient goes into a coma: They wake up, they go into a vegetative state, or they go into a minimally responsive or minimally conscious state, as Abdulla did. If a patient becomes vegetative, they won't respond to the world around them. If they're minimally conscious, they can respond, but their response doesn't amount to much. For example, Dr. Lee says, a minimally responsive patient might blink if an object gets too close to their face.

She adds that patients who recover from brain injuries might not remember what led to their injury. "It would not be uncommon for people who wake up from traumatic brain injury to not recall the incident," she explains. The reason is simple: When the brain is being injured, it isn't recording memories.

RELATED: Woman Who Gave Birth While in a Coma Dies 3 Years After Regaining Consciousness

Webair says his mom said his name when she woke up from the minimally responsive state she was in. He says his mother's case highlights why you shouldn't give up on loved ones who haven't been responsive for years.

"I shared her story to tell people not to lose hope on their loved ones," he told The Nation. "Don’t consider them dead when they are in such a state. All those years, the doctors told me she was a hopeless case and that there was no point of the treatment I was seeking for her, but whenever in doubt I put myself in her place and did whatever I could to improve her condition.”

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The medical team are able to extract huge amounts of information from tiny fragments of DNA.

Campaigners say children who wet the bed and have daytime accidents are “suffering in silence”.

Motor vehicle crashes are the most common cause of emergency room visits, hospitalizations and deaths related to traumatic brain injury among people aged 15 to 34, according to a 2013 report by the Centers for Disease Control and Prevention.