Prof Gerry Killeen recently made headlines on foot of warnings about the easing of Covid-19 restrictions.
Speaking tohe says his expertise all began with pig dung.
“I was asking myself ‘What does a pig manure biochemist have to offer?’ And I knew that was a pretty short list.”
He kept an eye on international job advertisements and spotted one looking for someone to develop plant-based mosquito repellent.
“I didn’t know anything about mosquitos at the time, but I knew about plant chemistry.”
He didn’t get the job he applied for, but his application was spotted by a scientist in a laboratory in New Orleans who made contact.
He was invited to join the lab team and spent more than three years there working with mosquitos.
“I wasn’t particularly good at it, but I got into mathematical modelling. I started trying to help a professional mathematical modeller. He encouraged me to give it a try myself and I turned out to be reasonably competent at that, and that was probably the major skill that got me my first job in Africa.”
Living the dream, Prof Killeen’s first African gig was at the International Centre for Insect Physiology and Ecology in west Kenya on the shores of Lake Victoria.
He joined a team of “really motivated, hardworking young Kenyans, Tanzanians, and Ethiopians” who were working on diverse aspects of malaria, transmitted to humans via mosquitos.
“I learned a lot and I got into community-based vector control,” he says. The mosquito is the vector for transmission of malaria.
Prof Killeen’s next post was at the Ifakara Health Institute in Tanzania, where he remained for 17 years.
Ifakara is known globally for its malaria vector research.
“It used to hold the world record for measured malaria transmission exposure, so it’s a good place to work if you like mosquitos,” he says.
“For people living in that valley, they would have had malaria parasites injected into their bloodstream by a mosquito several times a day.
There was no question about whether somebody had malaria. The question was what density of parasite did they have in their blood and had many different malaria parasite strains were they carrying around.
People could develop immunity, he says, but “it’s partial”.
“The problem with malaria immunity is it doesn’t stop you getting infected, it doesn’t stop the course of your infection,” he says.
“But it does allow you to suppress the parasite density in your blood. You still carry it around, but you’ve got a better balance in the war with the parasite. It becomes a chronic disease.
“In Africa, by the time you are five years old, you either have enough malaria immunity to keep you alive for the rest of your life, or you didn’t make it.”
Similarities between malaria and Covid-19
Prof Killeen says malaria has “lots of analogies with Covid-19”.
“Most people are not vulnerable, but there is a small proportion of the population that is and they really pay the price and they rely on the immune people to do all the things that are required to protect them.”
So what strategies did they use to stop transmission of malaria during his time in Africa?
The biggest breakthrough, Prof Killeen says, was the introduction of insecticide-treated bednets. Trials in the 1990s had shown you could “halve childhood mortality with treated bednets”.
However limited funding meant the nets were destined for children with no immunity and pregnant women, as per World Health Organisation (WHO) policy, he says.
“What was missing from that policy was the fact that mosquitos don’t get all their blood from pregnant women and small children. Most of the time, they are feeding off the old farmer in the fields or the woman at home cooking. To kill off the mosquito population, everyone has got to use the net.”
Prof Killeen wrote a paper arguing in favour of a universal policy of bednets which he says he “leaked in advance into the WHO system” so that by time his paper came out, the policy had been changed.
The bednet rollout was scaled up and the impact, he says, was “spectacular, hundreds of millions of malaria cases prevented”.
“I often describe myself as the guy at the front of the boat ringing the bell and shouting: ‘Iceberg!’. Covid isn’t my first iceberg. I have kind of a track record of calling icebergs,” he says.
He’s been shouting “iceberg” in relation to Covid-19 since early March.
He describes an article that appeared in UK medical journal The Lancet, on January 20, pointing to a pandemic as “an absolute fire-alarm paper”. He says normally it takes three months to get a paper reviewed before appearing in The Lancet, “but this paper got reviewed in six days”.
“It was all out there in January, February, certainly March. I started sending emails in the first week of March warning people to watch out for this [disease],” he says.
The warnings prompted his own speedy departure from Africa in early March — his 13-year-old daughter was already in school in Bandon, West Cork, and he had been appointed to a new role at UCC.
“When I read really good reports coming out in English from Chinese physicians, really describing in detail what we were dealing with, I have got to say it really set me back.
“For a day or two, I panicked and then I composed myself and thought: ‘OK, this one is too big to ignore’.”
After sending some “technically explicit advisories” to colleagues in Tanzania in relation to dealing with Covid, “we [he and his wife] packed our bags in 24 hours and scrambled to the airport and got one of the last planes out”.
The thing about Covid, he says, is it can hide, unlike a disease like ebola, which caused major loss of life in West Africa between 2014 and 2016.
“There is no such thing as an asymptomatic ebola case. If you start bleeding from the nose, the ears, the eyeballs, people notice it,” he says.
“You do have that initial asymptomatic period, but sooner or later, it’s plain as day that you have ebola. You don’t have this sneaky asymptomatic/mildly symptomatic disease like Covid.”
Covid is like malaria in that the symptoms are “very vague” he says.
“Covid can manifest itself in almost any way. There is a paper written by a Chinese allergy specialist on ‘The 11 Faces of Covid’, and he describes 11 patients in his clinic who look like they have 11 different diseases,” says Prof Killeen.
“Malaria is the same. One of the things that makes it really difficult for physicians is there are no clear-cut symptoms.
“If you wanted to screen for Covid in this country, you would have to test everybody. I mean 4.8m people, and that’s not going to happen.
“The key part is you are still getting the asymptomatics, you are still going to miss a lot of people, so screening is a very important part of the response, but it’s not a substitute for prevention measures and those prevention measures need to be pre-emptive and — like malaria — you have to stop transmissions”
Easing restrictions is not a prevention measure he says, and he warns that the phased easing of Covid restrictions here will re-ignite transmission of the disease.
If we were to follow it [the phased roadmap plan] as it is laid out and let things rip without re-imposing any restrictions, I could guarantee you a biblical plague by Christmas.
Prof Gerry Killeen is AXA Research Chair in Applied Pathogen Ecology, School of Biological, Earth & Environmental Sciences, and Environmental Research Institute, UCC