A study of the neurological disorder associated with acute haemorrhagic conjunctivitis due to enterovirus 70

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.

Re-emergence of a coxsackievirus A24 variant causing acute hemorrhagic conjunctivitis in Brazil from 2017 to 2018

A large outbreak (over 200,000 cases) of acute hemorrhagic conjunctivitis (AHC) took place in Brazil during the summer of 2017/2018, seven years after a nationwide epidemic, which occurred in 2011. To identify the etiological agent, 80 conjunctival swabs from patients with a clinical presentation suggestive of AHC were analyzed at the national enterovirus laboratory. Real-time RT-PCR for human enteroviruses was performed, and enterovirus RNA was detected in 91.25% (73/80) of the specimens. Twenty-nine swab fluids were used to inoculate cell cultures (RD and Hep2C), and 72.4% (21/29) yielded a cytopathic effect. Genotype IV coxsackievirus A24v (CV-A24v) was identified as the causative agent of the outbreak. Phylogenetic analysis based on the VP1 gene revealed that Brazilian isolates were genetically related to strains that caused an outbreak in French Guiana in 2017. Our results show the re-emergence of CV-A24v causing AHC outbreaks in Brazil between the end of 2017 and the beginning of 2018.

Increased Incidence of Obstructive Sleep Apnea in Hospitalized Children After Enterovirus Infection: A Nationwide Population-based Cohort Study

BACKGROUND

We report the first nationwide population-based cohort study using Taiwan's National Health Insurance Research Database on the association between enterovirus (EV) infection and the incidence of sleep disorders in a pediatric population.

METHODS

Two matched groups of children under 18 years of age were included in the analyses for nonapneic sleep disorder and obstructive sleep apnea (OSA). Among them, 316 subjects were diagnosed with OSA during the surveillance period, including 182 in the EV infection group and 134 in the non-EV infection group.

RESULTS

Hospitalization because of EV infection was associated with OSA after adjusting for age, sex, urbanization atopic disease and perinatal complications (adjusted hazard ratio: 1.62, 95% confidence interval: 1.18-2.21; P = 0.003). An additional factor significantly associated with sleep apnea was allergic rhinitis (hazard ratio: 4.82, 95% confidence interval: 3.45-6.72).

CONCLUSIONS

Children with severe EV infection (ie, requiring hospitalization) carry a significantly higher risk of developing OSA, particularly in those with allergic rhinitis. As pediatric obstructive sleep apnea is a treatable sleep disorder, we emphasize regular follow-up and early detection in children with EV infection.

Acute Flaccid Paralysis and Enteroviral Infections

PURPOSE OF REVIEW

The focus of this review is on enterovirus (EV)-associated acute flaccid paralysis (AFP) due to spinal cord anterior horn cell disease. Emphasis is placed on the epidemiology, pathogenesis, diagnosis, treatment, and outcome of AFP caused by polioviruses, vaccine-derived polioviruses, EV-D68, and EV-A71.

RECENT FINDINGS

Since the launch of The Global Polio Eradication Initiative in 1988, the worldwide incidence of polio has been reduced by 99.9%, with small numbers of poliomyelitis cases being reported only in Afghanistan, Pakistan, and Nigeria. With the planned phaseout of oral polio vaccine, vaccine-associated poliomyelitis is also expected to be eliminated. In their place, other EVs, chiefly EV-D68 and EV-A71, have emerged as the principal causes of AFP. There is evidence that the emergence of EV-D68 as a cause of severe respiratory disease and AFP was due to recent genetic virus evolution. Antiviral medications targeting EV-D68, EV-A71, and other EVs will likely be available in the near future. An effective EV-A71 vaccine has been developed, and preliminary investigations suggest an EV-D68 vaccine could be on the horizon. The eradication of poliomyelitis and vaccine-associated poliomyelitis is near, after which other EVs, presently EV-D68 and EV-A71, will be the principle viral causes of AFP. Moving forward, it is essential that EV outbreaks, in particular those associated with neurologic complications, be investigated carefully and the causal strains identified, so that treatment and prevention efforts can be rapidly developed and implemented.

The epidemiology of non-polio enteroviruses: recent advances and outstanding questions

PURPOSE OF REVIEW

There are over 100 serotypes of human enteroviruses, which cause a spectrum of illnesses, including meningitis, encephalitis, paralysis, myocarditis and rash. Increasing incidence of hand-foot-and-mouth disease in the Asia-Pacific region and recent outbreaks of enterovirus-associated disease, such as severe respiratory illness in the United States in 2014, highlight the threat of these viruses to human health.

RECENT FINDINGS

We describe recent outbreaks of human enteroviruses and summarize knowledge gaps regarding their burden, spectrum of diseases and epidemiology.

SUMMARY

Reported outbreaks of respiratory, neurological, skin and eye diseases associated with human enteroviruses have increased in frequency and size in recent years. Improved molecular diagnostics and genetic sequence analysis are beginning to reveal the complex dynamics of individual serotypes and genotypes, and their contribution to these outbreaks. However, the biological mechanisms underlying their emergence and transmission dynamics remain elusive. They are likely to involve changes in the virus, such as fitness, antigenicity, virulence or tropism, and in the human population, such as levels of sanitation and of homotypic and heterotypic immunity. Improvements in surveillance, serological surveys and detailed genetic and antigenic characterization of viral populations would help to elucidate these mechanisms. This will be important for the design of outbreak control and vaccine development strategies.

Acute hemorrhagic conjunctivitis: anti-coxsackievirus A24 variant secretory immunoglobulin A in acute and convalescent tear

Purpose

The purpose of this paper is to present the clinical course of a laboratory-acquired case of acute hemorrhagic conjunctivitis (AHC) caused by coxsackievirus A24 variant (CA24v). Also, the anti-CA24v neutralizing activity and anti-CA24v immunoglobulin (Ig) G and secretory IgA (sIgA) in acute and convalescent tears and/or sera are presented.

Case

A 60-year-old male presented with acute-onset left eyelid edema, tearing, conjunctival erythema, pain, foreign body sensation, and subconjunctival hemorrhage 24 hours after suspected laboratory exposure. Bilateral conjunctivitis presented 24 hours later and resolved in 10 days.

Methods

Tear and blood samples were collected for virus isolation and neutralizing assays. CA24v-reactive IgG and sIgA in tear and/or serum samples were detected by immunofluorescent antibody analysis of ethanol-fixed virus-infected cells.

Results

Peak tear neutralization titers (1,000–1,500 U/mL) against the isolated virus occurred 1 day post-onset (po) of AHC. Tear neutralization titers became undetectable by the sixth day as serum neutralization titers became detectable on the ninth day po (60 U/mL), peaked by 21 days (3,000 U/mL), declined by 1 year to 200 U/mL, and remained at 30 U/mL 5 years po. Antibody to human IgG, IgA, and secretory component (sIgA) reacted with CA24v-infected cells treated with pooled acute tears collected 1–4 days po. Predominantly, sIgA was detected in CA24v-infected cells treated with tears collected 4 years and 5 years post-AHC, while convalescent serum contained predominantly anti-CA24v IgG.

Conclusion

AHC was confirmed by CA24v isolation, tear anti-CA24v neutralizing activity, and seroconversion. The detection of CA24v-reactive IgG, sIgA, and neutralizing activity in tears collected 1–4 days po of AHC supports plasma extravasation of IgG and suggests a defensive role for tear anti-CA24v sIgA. The results suggest that immunofluorescent antibody analysis of tears for persistent anti-CA24v sIgA may be useful in epidemiological monitoring of AHC.

Approach to a child with acute flaccid paralysis

Acute flaccid paralysis (AFP) is a clinical syndrome characterized by rapid onset weakness, that many times includes respiratory and bulbar weakness. AFP is a broad clinical entity with an array of diagnostic possibilities. An accurate and early diagnosis of the cause has important bearing on the management and prognosis. The immediate priorities in a child who presents with acute progressive weakness are; to detect and manage respiratory muscle weakness, to detect and manage bulbar weakness, evaluate for cardiovascular instability, detect and manage dyselectrolytemia or toxemia, and to detect and manage a spinal compression (traumatic, intraspinal collections). Urgent imaging of the spine is needed in settings where a spinal cord involvement is suspected. Compressive or traumatic spinal lesions may need early neurosurgical intervention. Anterior horn cell injury is usually due to direct viral infection. More distal pathologies are generally immune mediated and respond to immunomodulation. Irrespective of the cause, generalized weakness frequently affects respiratory and bulbar function. Such children need careful monitoring and respiratory support.

Systemic and ocular antibody responses to inactivated acute hemorrhagic conjunctivitis (AHC) virus; enterovirus 70 (EV70)

PURPOSE

Evaluate the immune response in rabbits injected with EV70, the agent of acute hemorrhagic conjunctivitis (AHC) and AHC associated neuropathy.

METHODS

Rabbits were injected intramuscularly with uv-light inactivated EV70 isolate J670/71. Neutralizing activity against EV70 was quantified in serum and tear samples and the immunoglobulin (Ig) classes of the neutralizing activity in serum identified by sucrose gradient ultra-centrifugation. Adjuvant muramyl dipeptide (MDP) was applied topically to assess the role of ocular inflammation on levels of neutralizing antibody, proteins and Ig in tears. The protective effects of human and rabbit sera and interferon-alpha (IFN-alpha) against EV70 were compared in human conjunctival and lens cells.

RESULTS

Sera collected at 6 and 13 d contained 19S IgM anti-EV70 neutralizing antibody, while serum collected 21 d post injection contained 19S IgM and 7S IgG anti-EV70 neutralizing antibody. Low titers of anti-EV70 activity (< or =30 U/ml) were detected in tears of seropositive rabbits. MDP induction of conjunctivitis in seropositive rabbits increased tear IgG concentration (3-fold) and anti-EV70 neutralizing antibody titers (> or =10-fold). The protective effect of the rabbit and human sera against EV70 infection in conjunctival, but not lens epithelial cells, was enhanced by the addition of IFN-alpha.

CONCLUSIONS

Immunization with uv-light inactivated EV70 elicits a classical humoral immune response in rabbits. The protective activity of serum in EV70-infected human conjunctival cells, but not lens cells, was increased by IFN-alpha. Adjuvant MDP-induced conjunctivitis, increased blood-conjunctival barrier (BCB) permeability and anti-EV70 neutralizing activity in tear of seropositive rabbits. The results suggest immunization with inactivated EV70 could provide systemic as well as ocular protection during natural EV70 infection.

Enterovirus infections: a review of clinical presentation, diagnosis, and treatment

The enteroviruses, RNA viruses of the Picornaviridae family, are ubiquitous pathogens which include more than 70 different serotypes that infect people of all ages and tend to occur seasonally in the summer and fall. Clinical manifestations may vary diversely with one serotype, while multiple serotypes can present with identical symptoms and may mimic bacterial infections. Most enterovirus infections cause benign, self-limiting disease; however, they can also produce severe and sometimes fatal illnesses such as meningitis, encephalitis, myocarditis, neonatal sepsis, and polio. Severe enterovirus infections are being diagnosed and treated earlier with better prognostic outcomes due to the advances of polymerase chain reaction technology in accurately detecting virus in patient fluids as well as the recent development of new antiviral therapies.

Treatment of picornavirus infections

The picornaviruses are a diverse group of viral pathogens that together comprise the most common causes of infections of humans in the developed world. Within the picornavirus family are three well-known groups of human pathogens-the enteroviruses (including polioviruses, coxsackieviruses, and echoviruses), the rhinoviruses, and the hepatoviruses (including hepatitis A). Recently, the parechoviruses (formerly, echoviruses 22 and 23) have been classified as a fourth genus of human picornaviruses. This article will focus on the enteroviruses and rhinoviruses agents, for which substantial effort has been expended and recent successes reported towards the development of safe and effective antiviral therapy.

Antiviral therapy for enteroviruses and rhinoviruses

The picornaviruses are a diverse group of viral pathogens that together comprise the most common causes of infection of humans in the developed world. Within the picornavirus family are three well-known groups of human pathogens--the rhinoviruses, the enteroviruses (including polioviruses, coxsackieviruses and echoviruses) and the hepatoviruses (including hepatitis A virus). This article will focus on the rhinoviruses and enteroviruses, agents for which substantial effort has been expended, and recent successes reported, toward the development of safe and effective antiviral therapy.

Guillain-Barré syndrome. A prospective clinical study in 25 children and comparison with adults

Children who fulfilled the recognized diagnostic criteria for Guillain-Barré syndrome (GBS) were studied prospectively from 1982. After detailed clinical evaluation and investigation, severity of disease was graded on a disability scale ranging from 1 to 6, and the time taken from the 1st day of illness to reach important clinical landmarks was noted. All children were monitored for a minimum of 1 year and observations on them were then compared with those on 92 adults with GBS seen during the same period. Twenty-five children, evenly distributed between the sexes, were seen between 1982 and 1989 and constituted 22% of all GBS patients seen during this period. Children had a more acute form of onset than adults, 80% becoming bedbound within 7 days, and a higher incidence of cranial nerve palsies (76% vs 55%). The incidence of respiratory paralysis was 40% and of dysautonomia 20%, which was similar to findings in adults. Children fared marginally better than adults: 72% were ambulant at 1 year, 12% bedbound and 16% decreased. The prognosis of ventilated patients was relatively poor in both groups, but children with the hyperacute form of the disease had twice the probability of adults to attain independent walking at 1 year (0.63 vs 0.33).

Monoclonal anti-idiotypes induce neutralizing antibodies to enterovirus 70 conformational epitopes

Monoclonal antibodies (MAbs) directed against the prototype enterovirus 70 (EV-70) strain J670/71 were generated and characterized in order to produce anti-idiotypic MAbs (MAb2s) for use as surrogate immunogens. Western immunoblot and radioimmunoprecipitation assays suggested that all the MAbs recognize conformational epitopes on the virion surface. An EV-70-neutralizing antibody, MAb/ev-12 (MAb1), was selected for the production of MAb2s. Five MAb2s were selected for their capacities to inhibit the interaction of MAb/ev-12 with EV-70 in dot immunobinding inhibition and immunofluorescence assays. In addition, these five MAb2s inhibited virus neutralization mediated by MAb/ev-12, suggesting that they recognize paratope-associated idiotopes. In competition enzyme immunosorbent assays, none of the five MAb2s recognized other neutralizing and nonneutralizing EV-70-specific MAbs, demonstrating that the MAb2s were specific for private idiotopes. Immunization with each of the MAb2s was carried out for the production of anti-anti-idiotypic antibodies (Ab3). All five MAb2s induced an immune response. Moreover, results suggested that they share idiotopes, since MAb2-MAb/ev-12 binding could be inhibited by homologous as well as heterologous Ab3s. Ab3 sera were shown to possess antibodies capable of immunoprecipitating 35S-labeled viral proteins in the same manner as MAb/ev-12. Nine of 15 mice immunized with MAb2s demonstrated Ab3 neutralizing activity specific for the prototype EV-70 strain, J670/71. The potential application of MAb2s to serve as surrogate immunogens for conformational epitopes is substantiated by the results presented in this report.

Clinical and electrophysiological aspects of acute paralytic disease of children and young adults in northern China

Acute peripheral nervous system diseases leading to paralysis in children are rare in Europe and the USA, whereas epidemics of a Guillain-Barré-like syndrome occur annually among children in rural parts of northern China. To clarify the features of this disorder 36 patients, aged 15 months to 37 years (median 7) with this syndrome were investigated; 91% were from rural areas. In 47%, a prodromal illness was reported in the preceding 4 weeks. Leg weakness and resistance to neck flexion were the earliest symptoms. The weakness ascended rapidly and symmetrically to affect the arms and respiratory muscles, with maximum weakness occurring a mean of 6 days after onset of weakness. Bulbar weakness occurred in 61% of patients, but only 1 had extraocular paresis. Respiratory assistance was needed by 31% of patients. Tendon reflexes were lost as weakness developed. 42% of patients had raised concentrations of protein in the cerebrospinal fluid, and the mean cell count was 3 cells/microliters (range 0-12/microliters). Electrodiagnostic studies in 22 patients showed severe reductions in motor evoked amplitudes from distal stimulation. Sensory action potentials were normal. Electromyography revealed denervation potentials in limb muscles. The distinctive epidemiological, clinical, and neurophysiological characteristics of this illness suggest that the disorder is different from both Guillain-Barré syndrome and poliomyelitis. The neurophysiological findings support the hypothesis that the disorder is a reversible distal motor nerve terminal or anterior horn cell lesion.

Management and prevention of ocular viral and chlamydial infections

A majority of cases of preventable and/or curable ocular morbidity and blindness are caused by ocular infections. They may account for 70 to 90% of all ocular morbidity seen by family doctors, general practitioners, health centers, and local ophthalmologists in both developed and developing countries. Unfortunately, most health authorities and doctors, including ophthalmologists, consider these diseases to be of little or no importance because they are not fully aware of the high prevalence of these infections and the blinding sequelae which may occur following incorrect diagnosis and treatment. Also, they are not aware of the social and economic impact of these infections in the absence of proper management and implementation of preventive measures. In this review, we examine present knowledge of chlamydial and common viral ocular infections. We discuss the problems of diagnosis, management, and prevention and propose solutions relevant to developed and developing countries.

[Acute hemorrhagic conjunctivitis, in Cuiabá, Mato Grosso, Brazil 1983]

Foi feita investigação de natureza etiológica clínica e laboratorial durante uma epidemia de conjuntivite hemorrágica aguda (CHA), ocorrida em Cuiabá, MT durante os meses de dezembro de 1982 e fevereiro de 1983; atendidos 68 pacientes e colhidos espécimes da conjuntiva, orofaringe e soro. Em 28 pares de soros foram realizados testes de neutralização em tubos de cultura de tecidos para o enterovirus 70 (EV 70) e fixaço do complemento para os adenovirus. Os resultados revelaram conversão sorológica de 89,3% (25 pares de soro) para o EV 70. A Secretaria de Saúde do Estado do Mato Grosso estima que aproximadamente 70% da população tenha sido atingida durante o surto. Não foram observadas evidências de comprometimento neurológico em pacientes de conjuntivite, durante ou logo após o surto.

Neurological complications of acute haemorrhagic conjunctivitis

Forty four cases of the neurological complications of acute haemorrhagic conjunctivitis (AHC) seen in India during 1981 epidemic are reported. The disease predominantly affected adult males. The preceding attack of AHC, a latent period, prodromal symptoms of fever, myalgia and root pains followed by acute onset of lower motor neurone paralysis of limbs and/or cranial nerves formed the classical picture of neurological involvement. The recovery was poor and nearly half of the patients remained severely handicapped. Electrophysiological studies showed early appearance of widespread fibrillations and fasciculations, large polyphasic potentials of increased amplitude and reduced interference pattern. Nerve conduction studies were normal in most of the cases. Cerebrospinal fluid (CSF) examination revealed lymphocytic pleocytosis and rise in protein content. Significant antibody titres against enterovirus type 70 (EV 70) were demonstrated in the serum and the CSF. HLA studies showed low occurrence of A2 and B15 HLA antigens. Muscle biopsies revealed neurogenic atrophy and sural nerve biopsies were histologically unremarkable. The similarities of this disease with poliomyelitis and its pathogenesis are discussed.