Neurological complications of acute haemorrhagic conjunctivitis

An outbreak of acute hemorrhagic conjunctivitis due to Coxsackievirus A24 in a residential school, Naharlagun, Arunachal Pradesh: July 2023

PURPOSE

An acute conjunctivitis outbreak was investigated at a residential school in Naharlagun, Arunachal Pradesh, Northeast India, in July 2023. We aimed to identify the etiological agent and assess any complications in follow-up cases.

METHODS

We used a structured questionnaire to record clinical findings and followed up with cases one-month post-conjunctivitis. Sixty-one cases were examined and eight conjunctival and oropharyngeal swab samples were collected after obtaining informed consent from guardians/school authorities. We screened for 33 viral and bacterial pathogens using an IVD-approved Real-time PCR assay. Further, the samples were subjected to nucleic acid sequencing.

RESULTS

Among 465 screened students and staff, 80 individuals (approximately 17.2%) showed acute hemorrhagic conjunctivitis symptoms among which 61 cases were available for clinical examination. We identified the Enterovirus responsible by targeted sequencing using next-generation sequencing. The etiological agent was found to be Coxsackievirus A24, a member of Enterovirus C, in seven out of eight samples subjected to sequencing. Common symptoms included conjunctival hyperemia and foreign body sensation (100%), bilateral eye involvement (73.8%), eye pain (70%), watery discharge (49.2%), and eyelid swelling (38%). Only 6.5% had purulent discharge. Most cases resolved within 5-6 days, with only 9.8% reporting abdominal symptoms post-conjunctivitis. No serious complications occurred within one month. Throat swabs aided in diagnosing enterovirus infections alongside eye swabs.

CONCLUSIONS

The outbreak of acute conjunctivitis was caused by Coxsackievirus A24, a member of Enterovirus C. Cases resolved spontaneously within 6-7 days, with no severe complications. Collecting oropharyngeal swabs alongside conjunctival swabs could improve enteroviral conjunctivitis diagnosis.

Life-Threatening Enterovirus 71 Encephalitis in Unrelated Children with Autosomal Dominant TLR3 Deficiency

PURPOSE

Enterovirus A71 (EV71) causes a broad spectrum of childhood diseases, ranging from asymptomatic infection or self-limited hand-foot-and-mouth disease (HFMD) to life-threatening encephalitis. The molecular mechanisms underlying these different clinical presentations remain unknown. We hypothesized that EV71 encephalitis in children might reflect an intrinsic host single-gene defect of antiviral immunity. We searched for mutations in the toll-like receptor 3 (TLR3) gene. Such mutations have already been identified in children with herpes simplex virus encephalitis (HSE).

METHODS

We sequenced TLR3 and assessed the impact of the mutations identified. We tested dermal fibroblasts from a patient with EV71 encephalitis and a TLR3 mutation and other patients with known genetic defects of TLR3 or related genes, assessing the response of these cells to TLR3 agonist poly(I:C) stimulation and EV71 infection.

RESULTS

Three children with EV71 encephalitis were heterozygous for rare mutations-TLR3 W769X, E211K, and R867Q-all of which were shown to affect TLR3 function. Furthermore, fibroblasts from the patient heterozygous for the W769X mutation displayed an impaired, but not abolished, response to poly(I:C). We found that TLR3-deficient and TLR3-heterozygous W769X fibroblasts were highly susceptible to EV71 infection.

CONCLUSIONS

Autosomal dominant TLR3 deficiency may underlie severe EV71 infection with encephalitis. Human TLR3 immunity is essential to protect the central nervous system against HSV-1 and EV71. Children with severe EV71 infections, such as encephalitis in particular, should be tested for inborn errors of TLR3 immunity.