Jade Small
Jade Small
December 11, 2024 ·  3 min read

What Causes Conjunctivitis? A Panoply of Pathogens, Study Shows

Conjunctivitis, often called pink eye, has long been associated with certain telltale signs and common causes. However, a recent study has unveiled a more complex picture, suggesting that the pathogens behind conjunctivitis are far more varied than previously thought. This discovery is not only reshaping how medical professionals view the condition but also highlighting the importance of advanced diagnostic tools.

A Closer Look at the Study’s Findings

Close up of woman face with red eye. Swollen eyelids, irritation and itching of eyes caused by conjunctivitis, allergy, inflammation, infection. Dry eye syndrome
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Researchers conducted a cross-sectional study on 52 patients across multiple locations, including the U.S. and Israel, to identify the pathogens responsible for conjunctivitis. Using RNA deep sequencing, they discovered a wide range of culprits, including human adenovirus species D, herpes simplex virus type 1, and even SARS-CoV-2. Surprisingly, only 8% of cases were bacterial, while 54% were viral—challenging traditional assumptions about the condition.

Dispelling Common Myths About Symptoms

Woman with red eye suffering from conjunctivitis, closeup
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For years, medical teachings have associated purulent (pus-like) discharge with bacterial conjunctivitis and tearing with viral infections. Yet, the study revealed that most patients with purulent discharge had viral infections, not bacterial ones. This underscores the difficulty of diagnosing conjunctivitis based solely on symptoms, as the pathogens vary widely depending on geography and circumstances.

Regional Differences in Pathogens

Close up of male brown bloodshot eyes and redness with vessels. Concept of keratitis, inflammation and ophthalmology.
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The study highlighted significant regional differences in conjunctivitis pathogens. For example, human adenovirus species D was more prevalent in California, while Israel saw cases of human adenovirus species B. These findings suggest that the local environment plays a crucial role in determining which pathogens are most likely to cause infections, making location-specific approaches to diagnosis essential.

The Role of Advanced Diagnostic Testing

Close Up of Man Touch His Severe Bloodshot Red Blood Eye Affected by Conjunctivitis or After Allergy. Man with Viral Blepharitis, Conjunctivitis, Adenoviruses. Irritated, Infected Eye. Copy Space
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Traditional diagnostic methods, like culture and polymerase chain reaction (PCR), often require healthcare providers to guess which pathogens to test for. In contrast, RNA deep sequencing can identify any pathogen in a sample, making it a promising tool for surveillance and diagnosis. Although currently costly and not widely available in clinical settings, this technology holds the potential to revolutionize how eye infections are diagnosed.

The Public Health Implications of Pink Eye

Pink eye Conjunctivitis in a girl's eye
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Conjunctivitis isn’t just an individual health issue; it has broader public health implications. For example, a recent outbreak in Pakistan led to the closure of over 50,000 schools due to more than 300,000 reported cases. Researchers emphasized that conjunctivitis could even serve as an early warning sign of epidemics or pandemics, as seen during the initial detection of COVID-19.

Challenges in Widespread Testing

Close up of two annoyed red blood eyes of male affected by conjunctivitis or after flu, cold or allergy. Concept of health, disease and treatment. Copy space for advertisement. With place for text.
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Despite its promise, RNA deep sequencing isn’t yet practical for everyday use. Insurance doesn’t cover the tests, and their high cost makes them inaccessible to many. However, experts remain optimistic that advancements in technology will eventually make these tests more affordable and commonplace, enabling faster and more accurate diagnoses.

Why Better Testing Matters

Close up of a severe bloodshot eye. Blepharitis, Conjunctivitis condition
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Accurate diagnostic tools are vital for treating conjunctivitis effectively and preventing its spread. Most cases are self-limiting, but proper diagnosis can help ensure the right treatment and reduce the risk of unnecessary antibiotic use. Additionally, better testing can determine which cases require isolation to prevent outbreaks.

The Path Forward: Vigilance and Innovation

Close up of one annoyed red blood eye of male affected by conjunctivitis or after flu, cold or allergy. Concept of health, disease and treatment. Copy space for advertisement. With place for text.
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The findings from this study underscore the need for continued innovation in diagnostic tools and public health surveillance. Researchers stressed the importance of monitoring infectious eye diseases as part of epidemic preparedness. As technology advances, there is hope that RNA deep sequencing and similar methods will become integral to clinical practice, offering new ways to combat conjunctivitis and other infectious diseases.

Conclusion: Redefining Our Understanding of Pink Eye

Macro of conjunctivitis red eye.
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This study has challenged long-held beliefs about conjunctivitis, revealing a diverse array of pathogens and highlighting the limitations of traditional diagnostic approaches. While most cases of pink eye are viral and self-limiting, understanding its causes is crucial for improving treatment, reducing unnecessary antibiotic use, and addressing its public health impact. As diagnostic technology evolves, so too will our ability to tackle this common yet complex condition.

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