Mosquito resistance to insecticides remains a growing concern, according to WHO estimates revealed at the American Society of Tropical Medicine and Hygiene meeting in Atlanta recently.

WHO reports 60 countries have recorded mosquito resistance to at least one of the four insecticides used in long-lasting insecticide treated nets (LLINS) and indoor residual spraying (IRS) since 2010. Of these, 49 countries have reported resistance to two or more insecticide classes. WHO says that if resistance continues to intensify, the mosquito-killing capacity of LLINs and indoor residual spraying may steadily weaken.

This would be a tragedy for sub-Saharan Africa where acclaimed research last year demonstrated that LLINs accounted for about 78% of the substantial malaria gains over the past 15 years or so. (Read more about this here.)

If the battle against malaria is to continue to drive back this scourge from sub-Saharan Africa, the need to continue to develop new public health insecticides is paramount. Fortunately, due to the foresight of leading vector science academics who saw the potential threat over 15 years ago, the Bill & Melinda Gates Foundation and other forward thinking funders have invested appropriately in the search for new public health insecticides. IVCC was established in 2005 as the only vector control focused Product Development Partnership (PDP) and has worked closely with world-leading vector scientists and agro-chemical companies to design and develop novel public health insecticides targetted precisely at killing the mosquitoes that transmit malaria.

Professor Hilary Ranson, one of the world’s leading authorities on insecticide resistance, warned earlier this year that pyrethroid resistance is the biggest biological threat to malaria control in Africa. (Read about this here.) Together with other leading specialists in this area she says that the urgent need for new vector control products is apparent,  and the new vector control products that are in the pipeline must be rationally deployed in order to slow down future resistance developing.

IVCC has a healthy pipeline of novel vector control tools, itself a product of consistent commitment by public health funders and industrial partners to finding a solution to the global threat of insect-transmitted diseases.

*The effect of malaria control on Plasmodium falciparum in Africa between 2000 and 2015. S Bhatt, et al.

IVCC would be nothing without our industrial partners.

We have a great mission— to save lives by preventing malaria with repurposed or new classes of insecticides that kill the mosquitoes that transmit malaria.

Since 2005 we’ve worked with a great cloud of scientists, researching millions of chemical compounds to find the best ones to stop malaria. We’ve helped apply the best minds in chemistry, reformulations, and all kinds of other scientific magic that I know little about.

Except that it works, and it is working, and we’re nearly there with the new active ingredients that will transform malaria vector control. Yes, and save lives. Millions of lives. Young children and pregnant women will no longer die from this preventable disease.

So, it’s very appropriate on World Malaria Day, to say thank you to all IVCC’s industrial partners. That includes scientists at BASF, Bayer, Sumitomo, Syngenta and Mitsui. We couldn’t do it without your quiet, selfless dedication to solve a critical and global public health crisis. In the battle against malaria I think you are truly heroes.

Thank you for everything you do. You are truly making the world a better place.

Watch the film Heroic Chemistry 

Although I have never lived in Africa, I’ve travelled there enough times to have a reasonable feel for the place. Urban Africa, busy, chaotic and unsafe contrasts enormously with the friendliness and warmth of Africans in rural communities, who despite their obvious hardship, will ask me to stop and share a cup of bitter tea with them.   The remote villages I visit lack many of the conveniences that we take for granted.   Mostly, there’s no running water, electricity is occasional and the air at dusk is filled with smoke as food is prepared and cooked in family compounds. Living is basic, but there’s a strange contrast between pinging money using mobile phones with crushing caterpillars to eat and livestock living amongst families with crowds gathering around flat screen TVs to watch Champions League football.

Life can be exceptionally tough.  Basic food may be available year-round for most so while there may be little excess it looks like no one starves.  There’s not much money and that’s ok when hard work is the main price for food, but the lack of access to a modern healthcare infrastructure can mean that when disease hits, there can be no money to pay for treatments, and this can devastate families and villages without warning.

90% of malaria cases occur in sub-Saharan Africa, and kills over 400,000 people every year – the vast majority of which are children under five.

Many villages have insecticide-treated bednets which provide proven malaria protection when sleeping at night. But there are never enough, mosquitoes can bite at times when no one is under their net and outside the home, and not everyone likes to use them.   Now and again when you ask if a householder has a bednet, they pull out an unused net, still in the bag to show.

Insecticide treated bednets not only provide personal protection through the physical barrier of the net, but the insecticide also provides effective community protection as contact with the net kills the mosquito meaning it can’t fly off and infect someone else.

However, this critical community effect which reduces the volume of biting mosquitoes, only works if the mosquito is not resistant to the insecticide.  Resistance is a huge issue today.  We are at a critical tipping point and without innovation in insecticide resistance, the huge gains in malaria reduction we have made since 2000 could rapidly unwind with devastating effect, but insecticide resistance is complex. There are different underlying mechanisms in different locations, species of mosquito and regions that impact the performance of different insecticides in different ways that makes measuring the benefits of different interventions on disease transmission complex.

That’s why the arrival of BASF’s Interceptor® G2 is so important.  This net introduces a safe and reformulated insecticide from agriculture into public health – a first in 30 years.  Because mosquitoes have not been exposed to it before, it will be effective against mosquitoes that are resistant to the insecticides that are commonly used on bednets.  Of course, this product alone will not solve the problem.  More resistance beating public health insecticides need to be developed and used in a way that preserves their effectiveness in the long term by developing and following resistance prevention strategies.

That’s why IVCC is working with companies across the world to develop new public health insecticides for bednets as well as new resistance beating formulas for spraying on the inside walls of homes, another proven and effective intervention.  We are also investigating a range of other technologies which will reduce outdoor biting.  We have a long way to go but we are hopeful that, together with our industry partners like BASF and our dedicated funders, innovation in vector control can help create a world without malaria.

There are thousands of species of mosquitoes that feed on the blood of a wide range of hosts including mammals, birds, reptiles and amphibians. Though the loss of blood seldom debilitates the hosts on which they feed, the saliva of mosquitoes can often result in an immune reaction, leading to a rash. Much more serious though, are the diseases that mosquitoes can transmit through their bites. In moving between their hosts, some mosquitoes transmit extremely harmful diseases affecting humans such as malaria, yellow fever, Chikungunya, West Nile virus, dengue fever, filariasis, Zika virus and other arboviruses.

I first became involved in research on mosquitoes and their control in 1983 when, as a final year undergraduate at the University of Dundee, I did a short research project on the biological control of the yellow fever mosquito, Aedes aegypti, using the ‘elephant mosquito’, Toxorhynchites brevipalpis. Toxorhynchites is a fascinating genus of mosquitoes with a wingspan which can exceed 12 mm. Fortunately, the large adult mosquitoes feed only on nectar and fruit juices. Better still, the larvae are predatory on other aquatic insects including other mosquito larvae.

Since the introduction of DDT in the 1940s, mosquito control programmes have used large amounts of insecticides from different insecticide classes in order to reduce or eradicate mosquito vector-borne diseases. In response to this insecticide selection pressure, mosquitoes have evolved several different mechanisms to resist their effect. The main two types of mechanisms found in mosquitoes are: mutations in the genes of the target site of an insecticide class, leading to target site insensitivity; and changes in the metabolic enzymes inside the mosquitoes meaning that insecticides are broken down before they can have their effect. It was the latter mechanism of resistance that was the subject of my PhD at the London School of Hygiene & Tropical Medicine during which I purified and characterised esterase enzymes associated with insecticide resistance in populations of the southern house mosquito, Culex quinquefasciatus, from Cuba and South America.

Whilst I continued to conduct research on mosquitoes off and on since the completion of my PhD, it wasn’t until very recently that I fully devoted my career to working on them. In 2010, I had what one might call a career epiphany moment, when I decided that I wanted to devote the rest of my working life to the control of mosquito vectors of malaria. As part of a consultancy with IVCC, I was visiting facilities in West Africa conducting vector research. One of the facilities we visited was IRSS/Centre Muraz in Bobo-Dioulasso, Burkina Faso and, during this visit, we went to a village in the Vallée du Kou where they were running a community trial on a new long-lasting insecticidal net (LLIN). As I stood outside one of the village huts, a group of children congregated to see what all of these strangers were doing in their village. We smiled at each other and waved. Then, as we left the village to drive back to town, I learnt that the number of infected mosquito bites these children received every year are in the hundreds and that malaria is the main cause of morbidityand mortalitywith children in the area. This was my motivation for wanting for wanting to join IVCC and, I’m very happy to say, I became a member of the IVCC team in December 2016.

Zika virus was discovered decades ago but wasn’t associated with birth defects until the 2015–2016 outbreak in Brazil. Research by Ling Yuan and colleagues in China, published in Science on 28th September 2017 (A single mutation in the prM protein of Zika virus contributes to fetal microcephaly),  demonstrates that a single point mutation that occurred in the Zika virus in 2013, before an outbreak in French Polynesia, may have been responsible for this virus starting to cause microcephaly (abnormally small head size).

Since the shocking increase in birth defects linked to Zika virus infection was discovered, congenital Zika syndrome has spread to many countries but overall numbers have not increased as rapidly as feared (the Pan American Health Organization reports 2,074 confirmed cases of congenital Zika syndrome in 2015 and up to the end September 2016 and a further 1,615 in the last 12 months). Zika has fallen out of the headlines and is no longer classified by the World Health Organisation as a ‘PublHealth Emergency of International Concern’. Does this mean the problem has gone away and all our attention is now elsewhere? Certainly not!

The problem has certainly not gone away for the children affected by Zika virus or for their families. Congenital Zika syndrome encompasses more than microcephaly. Other symptoms are decreased brain tissue, damage to the back of the eye, joints with limited range of motion and too much muscle tone restricting body movement soon after birth. Some children develop symptoms later and may not exhibit microcephaly at birth.

Nor has the problem gone away for people living in more than 90 countries where Zika virus is present or for travellers to these countries. Currently there are no licensed vaccines or therapeutics available to combat Zika and the advice from the US Centers for Disease Control for pregnant women is to avoid travel to affected areas and for men to avoid unprotected sex with partners for 6 months after returning if trying to conceive (Risk of Zika Selected Destination). A Zika infection is understood to lead to immunity to subsequent infections and this may account in part for the slowing of the rate of growth of the impact of Zika on local populations in the affected zones. However, many young women within these countries have not yet been infected and remain at risk.

What about the research effort against Zika? Is that coming up with any solutions? There are currently over 30 Zika virus vaccine candidates in development. Last year, the Food and Drug Administration approved the first human testing of a Zika vaccine candidate, and this summer, a US$100 million US government-led clinical trial is underway. However, there are considerable technical and commercial challenges ahead, including the complex ethical issues involved in conducting large scale efficacy trials in pregnant women.

What about new methods for control of the mosquito that transmits Zika virus? IVCC is supporting 9 of the projects within USAID’s US$30 million Grand Challenge for Combating Zika and Future Threats. These are research projects run by academic groups based in 5 different continents. They are bringing forward innovations to improve the monitoring and control of the key vector species, the Aedes aegypti mosquito. I am privileged to have been appointed by IVCC to coordinate the support for these 2-year projects which started at the beginning of 2017. Amongst the exciting innovations are automated traps that will count and identify their contents and transmit this information, enabling early detection of the vector and a rapid control response. Four of the projects are creating invisible barriers that will prevent mosquito bites. There are also two projects on new, biological-based control systems.