Please tell us about your current role and your work with HSL.
I’m a parasitologist and infectious disease physician based at the Hospital for Tropical Diseases. I have my own clinic as well as caring for patients on the wards, treating and managing various parasitic diseases. At HSL, I’m the clinical lead for the diagnosis of parasitic infections. To put my role into context, until 2014 I was the only consultant parasitologist in the entire NHS – now there’s one other employed part time, so still only one and a quarter of us at consultant level.
Although it’s a niche role, there’s a truly international flavour to our work, partly due to the patients we treat and partly due to the laboratory in which we work. The parasitology lab has been completely re-equipped since moving into the Halo. As the only specialist parasitology lab in the country, we have access to specialist tests which are not available elsewhere, as well as a high level of expertise among the clinical scientists and biomedical scientists who perform them.
We are a centre of excellence for parasitology, connected to the Hospital for Tropical Diseases, as well as whole network of pathology labs across the UK and abroad. Samples may be sent in for specialist primary diagnosis, or reference if a lab needs confirmation of a test result. There’s also a huge amount of email traffic that flows internationally, with scientists and clinicians asking for advice on cases or clinical problems that may be parasitic in nature.
What drew you towards infectious disease, and parasitology in particular?
I read Zoology at King’s College London, and followed that with a PhD in Parasitology at the Wellcome Foundation Research Laboratories, where I learned how anti-parasitic drugs were developed. My supervisor at the time encouraged me to pursue a medical career. I went straight from my PhD into a medical degree course, and ended up specialising in infectious diseases. I became the first consultant parasitologist in the NHS – so although I love it, it’s not really a job you plan for!
I am particularly interested in hydatid disease – a parasitic infection usually found in the liver, acquired from tapeworm eggs passed by dogs and foxes. Infected patients can remain asymptomatic for years before developing serious liver disease. Although the cystic form of hydatid disease is still endemic in parts of the UK, with changing patterns of migration and London being as multicultural as it is, most of the cases I now see are imported.
Chagas disease is another infection we deal with relatively often, which is endemic in South America and can lead to end stage cardiac failure if left untreated. As with hydatid disease, the aim for many of these parasites is to raise awareness, so that people are diagnosed earlier and treatment started promptly.
Malaria is of greatest concern globally in terms of the dreadful number of people it kills. It also kills travellers, especially those returning from West Africa. Our laboratory looks after the walk-in emergency service at the Hospital for Tropical Diseases at Mortimer Market, which provides a malaria diagnostic turnaround within one hour.
What are your research interests?
My research focuses on new diagnostic methods for a variety of parasitic infections, including malaria. Part of this has involved working closely with Spencer Polley, scientific lead for parasitology at HSL, in the development of new molecular tests.
We have been working with WHO since 2004, helping to improve the quality of malaria rapid diagnostic tests (RDTs). These provide prompt and accurate malaria diagnosis in places where microscopy services are not available.
We are also involved in quality improvement of parasitology services here in the UK. I work in the UK NEQAS Parasitology lab, which is situated in the Halo. We run a number of external quality assessment (EQA) schemes for malaria molecular diagnostics, malaria RDTs, toxoplasma serology, parasite serology and blood and faecal parasitology. EQA is fundamental to British pathology, improving the diagnosis of parasitic infections in labs across the country.
Has there been a particularly interesting or stand-out moment in your career?
As I mentioned before, I have a special interest in hydatid disease, particularly in the appearance of the alveolar form, which often presents late and causes substantial liver damage. Before we had drugs to treat it, 90% of infected individuals would die from the disease, often 10-15 years after diagnosis.
Alveolar hydatid disease is not currently transmitted in the UK. Public health measures, such as the de-worming requirement in the EU pet travel scheme, can help prevent this parasite from coming into the UK.
Alveolar hydatid are difficult cases to diagnose, which is why I’m part of a specialist team – including a dedicated liver surgeon and radiologist – looking after the majority of alveolar cases in the UK. We wouldn’t be able to do this without the knowledge, skills and expertise of the scientific staff in the highly specialised parasitology facility in the Halo.
Where do you see the future of diagnostics in the field of parasitology?
Parasitic infections have traditionally been diagnosed morphologically under the microscope, but advances in PCR and whole genome sequencing mean molecular diagnosis is becoming increasingly popular. We are working with the University of Bergen, for example, using whole genome sequencing to look for markers of drug resistance in Giardia infections. Unlike most bacteria, parasites are not easy to culture – therefore new molecular techniques will play a key role detecting drug resistance and improving treatment efficacy.
We are already seeing advances in serologically-based assays to improve diagnostic specificity and treatment monitoring. I think we will also see the development of more sensitive and specific RDTs, such as those currently being used for malaria.
We can only develop these new molecular and serologically-based approaches once we know what parasite we are actually dealing with. So, even though we are seeing many exciting new developments in the diagnosis of parasitic infections, microscopy will continue to play an important role in the years to come.