A pioneering metagenomics test at Great Ormond Street Hospital’s (GOSH) genomics laboratory saved the sight of Bristol GP Dr Ellie Irwin in 2025 after five years of a mystery eye infection that nearly cost her the eye. The metagenomic sequencing identified a rare strain of Leptospirosis — a bacterium endemic to South America — which conventional PCR testing had missed. A targeted three-week course of antibiotics cleared the infection, and Dr Irwin celebrated her wedding day in March 2025 free of symptoms. The case marks the first UK use of metagenomic sequencing in ophthalmology and signals a major shift in how rare and previously undiagnosable infections will be identified going forward.

The Case at a Glance

Dr Ellie Irwin, a 29-year-old GP trainee from Bristol, had endured five years of persistent inflammation and blurred vision in her right eye. Despite extensive testing and treatment at Moorfields Eye Hospital, no cause was found. By late 2023 she was preparing to consider eye removal — her words: “I had really just reached my breaking point.”

Her clinical team then partnered with the metagenomics service at Great Ormond Street Hospital (GOSH), part of work led by University College London (UCL). A single metagenomics test of the fluid inside her eye sequenced every fragment of genetic material present — and pinpointed an unusual culprit: Leptospira interrogans, a strain endemic to the Amazon basin. A three-week course of targeted antibiotics cleared the infection completely.

Five Years of a Mystery Eye Condition

Dr Irwin’s case illustrates how difficult chronic, low-grade infections can be to diagnose when standard testing fails. Her symptoms began in 2018 and worsened progressively. Multiple rounds of imaging, blood work and PCR tests narrowed nothing definitive.

What Is a Metagenomics Test?

A metagenomics test is a next-generation sequencing technique that reads all of the genetic material — DNA and RNA — in a clinical sample, without needing to know in advance what to look for. It then compares those genetic fragments against vast databases of known bacteria, viruses, fungi and parasites.

That fundamentally distinguishes it from traditional PCR testing. PCR (polymerase chain reaction) is targeted — you can only find what you specifically test for. If a clinician orders a panel of 20 likely pathogens, PCR will tell you whether any of those 20 are present, but it cannot identify the twenty-first organism that nobody thought to look for.

Dr Julianne Brown, principal clinical scientist at the GOSH metagenomics service, has described the technology as “an enormous step up — a complete game-changer,” precisely because it removes the need to guess what pathogen might be responsible.

How metagenomic sequencing compares to PCR

How the Metagenomics Test Cracked the Case

The breakthrough was the result of a collaboration between Moorfields Eye Hospital NHS Foundation Trust and the metagenomics laboratory at GOSH — a service developed over more than a decade by Professor Judy Breuer’s group at UCL.

1. A small fluid sample was aspirated from inside Dr Irwin’s eye (vitreous and aqueous humour) and shipped to the GOSH laboratory.
2. The sample’s total nucleic acid was extracted and sequenced using next-generation sequencing platforms.
3. Bioinformatic analysis matched the sequencing reads against reference genomes of bacteria, viruses, fungi and parasites.
4. The signal that came back matched Leptospira interrogans — a strain primarily found in tropical South America.
5. Targeted antibiotic therapy (a course tailored to leptospirosis) was prescribed; full clinical resolution followed within weeks.

This was, according to the Moorfields and UCL announcements, the first time metagenomic sequencing had been used in UK ophthalmology to resolve a chronic uveitis case.

The Amazon Connection: Why Leptospirosis Mattered

Leptospirosis is a bacterial infection spread mostly through water contaminated with the urine of infected animals (typically rodents and livestock). It is rare in the UK but more common in tropical and subtropical regions, particularly South America, South-East Asia and parts of Africa. Most cases cause flu-like illness or jaundice; ocular leptospirosis — chronic eye inflammation weeks or months after the initial infection — is far less commonly reported.

Dr Irwin had travelled in South America before her symptoms started, the most likely route of exposure. The strain identified by the metagenomics test was specifically endemic to that region — the kind of granular detail PCR panels in the UK simply would not have searched for.

The Future of Metagenomic Diagnostics

The Moorfields-GOSH case is one of several recent demonstrations that metagenomic sequencing is moving from research tool to mainstream diagnostic. A 2024 UCSF study reported that a single metagenomic next-generation sequencing test could diagnose nearly any infection across more than 4,800 patient samples, detecting 797 organisms — including viruses, bacteria, fungi and parasites — across a seven-year period. The study was published in Nature Medicine.

What’s expected to change over the next 3–5 years:

• Cost — currently around £1,300 per test in the UK, projected to fall as sequencing throughput increases.
• Turnaround — moving from days to same-day diagnosis in critical-care settings.
• Use cases — expanding into meningitis, encephalitis, sepsis of unknown origin, post-surgical infection, immunocompromised patients and chronic uveitis.
• Accessibility — more national and regional services standing up metagenomics capability outside specialist research centres.

What This Means for Patients

For most people, the practical implication of Dr Irwin’s case is not that they will need a metagenomics test — but that the field of infectious-disease diagnosis is changing fundamentally. The most important takeaways:

• Persistent, unexplained inflammation should not be dismissed. If you have had symptoms for months without a confirmed cause, ask whether advanced diagnostics are appropriate for your case.
• Travel history matters. Always tell clinicians about international travel, even years prior. Rare imported infections are an increasingly recognised cause of chronic inflammation.
• Specialist multidisciplinary review can change outcomes. Cases that have not been solved in primary care or routine ophthalmology often benefit from a second opinion at a tertiary centre.
• Diagnostic technology now moves quickly. A test that did not exist five years ago can solve a case that’s lasted five years.

Eye Health & Advanced Diagnostics in Turkey

Revitalize in Turkey is not affiliated with Moorfields Eye Hospital, GOSH, UCL, or the NHS — this case is shared here as health journalism. However, the broader principle it illustrates is one that defines how we manage every patient referred for treatment in Turkey: thorough pre-procedure diagnostics, multidisciplinary review and access to specialist expertise are non-negotiable.

Our partner ophthalmology centres in Turkey offer comprehensive eye assessment, advanced imaging (OCT, corneal topography, biometry) and full pre-operative workup as a standard part of every eye treatment programme — whether that’s trifocal lens replacement, cataract surgery, LASIK or treatment for a more complex condition. Patients with chronic or unexplained symptoms are referred to appropriate UK or specialist centres where indicated; our role is coordination, transparency and ensuring nothing is missed.

With over 21 years of experience in international medical tourism, Revitalize in Turkey coordinates eye care through JCI-accredited partner hospitals with English-speaking patient managers and full aftercare support.

Frequently Asked Questions

What is a metagenomics test?

A metagenomics test is a next-generation sequencing technique that reads all DNA and RNA in a clinical sample, then compares the fragments against reference databases to identify bacteria, viruses, fungi or parasites — without needing to know in advance what to look for.

How is a metagenomics test different from PCR?

PCR is targeted and detects only the specific pathogens it is designed to find. A metagenomics test is untargeted — it can identify any organism whose genetic material is present in the sample, making it uniquely useful for rare or unexpected infections.

Where can I get a metagenomics test in the UK?

Clinical metagenomics testing in the UK is currently provided by specialist NHS laboratories, including the GOSH metagenomics service in London (developed in partnership with UCL). Tests are accessed via referral from a treating clinician for selected complex cases.

Is Revitalize in Turkey affiliated with the GOSH metagenomics service?

No. Revitalize in Turkey has no affiliation with Great Ormond Street Hospital, UCL, Moorfields Eye Hospital, or the NHS. This article is shared as health journalism to inform readers about a major diagnostic advance. The GOSH metagenomics service is an NHS specialist laboratory in London.

How much does a metagenomics test cost?

A single clinical metagenomics test currently costs approximately £1,300 in the UK. Costs are expected to fall significantly over the next 3–5 years as sequencing technology scales.

What is leptospirosis and can it affect the eye?

Leptospirosis is a bacterial infection caused by Leptospira spread through water contaminated with infected animal urine. Most acute cases cause flu-like illness or jaundice. In rare cases — including Dr Ellie Irwin’s — chronic eye inflammation (ocular leptospirosis) can develop weeks or months after the initial infection.

Why is travel history important when diagnosing chronic infections?

Many rare infections that cause chronic inflammation are endemic to specific regions of the world. A patient’s travel history — even years before symptom onset — can be the single most important clue in narrowing diagnostic possibilities.

Could a metagenomics test help me?

For most patients with common conditions, standard diagnostics are sufficient. Metagenomic sequencing is most useful in chronic, unexplained, or treatment-resistant cases. Whether it is appropriate for your situation is a decision your treating clinician will make, sometimes after multidisciplinary review at a specialist centre.

Will metagenomics testing become standard?

Most experts in the field expect metagenomic sequencing to become a first-line diagnostic tool for complex infections within the next 5–10 years, as turnaround times shorten and costs fall. Wider adoption is already underway in critical care, neurology and ophthalmology.

Sources & Further Reading

1. University College London — Cutting-edge genomic technology saves woman’s eyesight (April 2025)
2. Moorfields Eye Hospital — New genomic test saves Moorfields patient’s sight
3. UCSF — 1 Genomic Test Can Diagnose Nearly Any Infection (Nov 2024)
4. Nature Medicine — Seven-year performance of a clinical metagenomic next-generation sequencing test
5. World Health Organization — Leptospirosis fact sheet