The inextricable march of time means half term has been and gone. Time also appears to be about as inextricable as the constant flow of electrons (or electricity!) to my 12-year-old son’s PlayStation. During this lockdown it has been his lifeline to the outside world and his friends. This flow of electrons may not have been quite as reliable if he lived in Texas where they have had the biggest energy blackout in U.S. history. As many as 15 million people have been without power (population of Texas is 29 million).
Texas not only has the biggest hats and cars, but it is second only to Alaska in total land area. This huge expanse (at 695,662 km²) is studded with crude oil and natural gas fields so a lack of power in such a state is indeed an oxymoron. It is huge when compared to the UK (at 242,495 km² ) and is even bigger than France (643.801km2). It normally experiences temperatures that rarely exceed 35oC or go below 0-5oC.
However, this has not been the case in the last few weeks during which time there has been a sudden and dramatic unprecedented drop in temperature. It has for instance been well documented in the press that thousands of cold stunned sea turtles have been rescued in the Gulf of Mexico off the coast of Texas.
A phenomenon known as a ‘wobbly polar vortex’ means that Texas (along with much of the U.S.) is now exposed to temperatures as low as -20oC. Temperatures have been so low that even wind turbines have frozen.
The situation is even more dire for non-renewable sources of energy. It lost an even bigger share of its energy generating infrastructure in the nuclear, gas and coal industries. This is so vast that Texas provides more than one-fifth of U.S. domestically produced energy. There is a lot to go wrong.
It has roughly 25% of the entire U.S gas reserves and 18,000 miles of interstate natural gas pipelines within its state borders. More gas leaves the state than enters it and it even has 10% of the nation’s total natural gas storage capacity, in underground storage. It also has vast crude oil reserves.
The polar vortex that occurs in the Arctic describes a strong westerly wind system that circulates the pole. This is a naturally reoccurring phenomenon that every other year or so appears to lose its stability by becoming weaker during winter. This essentially lets cold air spill out into the northern hemisphere over Europe or the U.S. causing extreme weather events.
Unforeseen weather events (hot or cold) and climate change have wide ranging effects for many species (not just our turtles). In particularly, even a slight change in temperature, heavily influences one creature especially. It is well known to transmit more disease than any other. The mosquito.
There are 3000 Species of Mosquitos but there is Just One that Causes Malaria
Surprisingly, there are more than 3,000 species of mosquitoes, but there are three species that are chief culprits and claim responsibility for the spread of disease in humanity. Anopheles mosquitoes are the only species known to carry malaria, but they also carry filariasis (or elephantiasis as in Joseph Merrick ‘Elephant Man’) and encephalitis. Culex mosquitoes transmit encephalitis, filariasis, and the West Nile virus. And Aedes mosquitoes carry yellow fever, dengue, and encephalitis.
Malaria is a disease that generally involves people, mosquitoes, the plasmodium parasite and ultimately, climate. In truth as most of us know it is not a disease that we need to worry about in the UK as we sit in the higher-mid latitudes (53.55° latitude and 2.43° longitude). Unfortunately, in the lower latitudes you would not be so lucky. The charity UNICEF describes the disease as ‘the largest killer of children’ – with one child dying from it every 30 seconds – about 3,000 every day.
Mosquitos are probably one of the most annoying things on the planet as they have the uncanny ability to miraculously disappear just before being swatted. More than this they are also public enemy number one in our fight against global infectious disease. Mosquito-borne diseases cause millions of deaths worldwide every year with a disproportionate effect on children and the elderly in developing countries.
Many more people will die in Africa from malaria than COVID-19 in 2021. Malaria killed 409 000 people in 2019 and 411 000 in 2018, most of them babies and toddlers in sub-Saharan Africa. All the key drivers of malaria transmission are in natural abundance in Africa, but climate change is a new addition.
As we mentioned earlier the genus Anopheles is the only mosquito to transmit malaria. Within this genus there are 460 recognised species but only three in particular are responsible for most of the transmission in Africa. These are Anopheles gambiae, Anopheles arabiensis and Anopheles funestus.
Mosquitos & the Parasite that Causes Malaria are Very Temperature Sensitive
Mosquitos are highly temperature dependent and much more than you would assume. Below 16oC the development of their larvae ceases and below 14oC they die. Assuming they do mature, the rate within which they feed is also temperature sensitive. At 17oC female Anopheles gambiae mosquitos feed every 4 days while at 25oC they have a blood feed every 2 days. The other key driver is that as rainfall increases their breeding habitat expands leading to dramatic increases in population and subsequent transmission.
Another hugely significant point is that development of the malaria parasite within female mosquitos is also equally sensitive to ambient temperature. In fact, the parasite has an exponential relationship to temperature. Even a small rise in air temperature will significantly reduce the time it takes for the parasite to mature by several fold. A small rise of 0.5oC in Kenya in the 1970s led to an eight-fold increase in reported malaria cases.
I mentioned the other week that according to the Goddard Institute for Space Studies (or GISS which is part of NASA) it was estimated that the year’s average temperature in 2020 was 1.02o C above the baseline of a 1951-1980 mean. You can begin to understand what the implications are. It comes as no surprise that a highly effective malaria vaccine is a major objective of global health research and we may now be a step closer. New accelerated vaccine design and development now make a vaccine for malaria much more feasible.
The Lift Cycle of the Plasmodium Parasite is Very Complex
Vaccines in use today protect people against either viral or bacterial illnesses. However, malaria is caused by a parasite; a malaria vaccine would be one of the first vaccines to protect against a parasitic disease in humans. Unfortunately, malaria parasites have an extraordinarily complex life cycle, and we only have a limited understanding of the immune response to malaria infection (this in turn varies by population and age group).
So, a vaccine for malaria is incredibly challenging. Because of the complex life cycle that the plasmodium parasite has it means there are thousands of potential antigens to tackle and harness. This is much more complex than a single target like the spike protein on a COVID-19 virus particle.
MultiMalVax (short for Multiple Malaria Vaccine) is a pan-European project that is addressing shortcomings in the fight against malaria. The overarching aim of the MultiMalVax clinical development programme is to develop the concept of a highly effective multi-stage malaria vaccine to the point of proof-of-concept and then of course undertake trials with the hope of delivering the finished article.
MultiMalVax has five partners across the EU involved in vaccine development, each contributing with specialised expertise and technology. This includes the Jenner Institute at the University of Oxford who devised the AstraZeneca COVID-19 vaccine. It also has key expertise in malaria vaccine development and is coordinating the overall project. Other partners are the European Vaccine Initiative (EVI) and the Université Pierre et Marie Curie (UPMC). These three are complemented by two pharmaceutical industry partners.
The MultiMalVax project has delivered a malaria vaccine that is now on the point of entering the final stages of human trials. This vaccine is due to be tested on 4,800 children in Africa after early trials yielded promising results. It is possible that the vaccine could be in use by 2024.
If proven to be effective this could be ground-breaking. Malaria occupies a unique place in the annals of history. Over millennia, its victims have included Neolithic dwellers, early Chinese and Greeks, princes and paupers. In the 20th century alone, malaria claimed between 150 million and 300 million lives, accounting for 2 to 5 percent of all deaths. Its chief sufferers today are of sub-Saharan Africa, Asia, the Amazon basin, and other tropical regions. This implies 40 percent of the world’s population lives in areas where malaria is transmitted.