Isolation of Coxsackievirus A24 variant from patients with hemorrhagic conjunctivitis in Cuba, 2008-2009

BACKGROUND

An outbreak of acute hemorrhagic conjunctivitis occurred in Cuba in 2008 and 2009.

OBJECTIVE

To determinate the etiological agent associated with the Cuban outbreaks of acute hemorrhagic conjunctivitis during 2008 and 2009.

STUDY DESIGN

Conjunctival swabs and/or faecal samples from 382 patients with clinical diagnosis suggestive of acute hemorrhagic conjunctivitis were subject to viral culture in HEp-2 human laryngeal epidermoid carcinoma cells. Positive samples were identified by a specific Coxsackievirus A24 variant PCR and the 3C protease region of 16 isolates was sequenced for phylogenetic analysis.

RESULTS

Enterovirus cytopathic effect was observed in 138 cases (36%). A higher percent of CA24v was recovered from faecal samples, 19 out of 45 cases (42.2%), than from conjunctival swabs, 127 out of 355 samples (35.8%). All isolates were identified as Coxsackievirus A24 variant. Phylogenetic analysis revealed that 2008 and 2009 Cuban outbreaks were caused by the same virus strains and that isolates were closely related to those from Taiwan (2006-2007), China (2007-2008) and Singapore (2005) with a bootstrap value of 71%.

CONCLUSIONS

Outbreaks of acute hemorrhagic conjunctivitis occurred in Cuba in 2008 and 2009 were caused by Coxsackievirus A24 variant. The faecal-oral route is another mode of transmission of CA24v in the acute hemorrhagic conjunctivitis outbreaks. Phylogenetic analysis of Cuban CA24v strains involved in an acute hemorrhagic conjunctivitis outbreak in 2008 and 2009 confirms a new introduction of the CA24 variant into the Americas from South-east Asia.

[Application of Susceptible-Infected-Recovered model in dealing with an outbreak of acute hemorrhagic conjunctivitis on one school campus]

To simulate intervention measures in controlling an outbreak of acute hemorrhagic conjunctivitis on one school campus by using the Susceptible-Infected-Recovered (SIR) model, to provide evidence for preparedness and response to the epidemic. Classical SIR model was used to model the epidemic. Malthusian exponential decline method was employed to estimate the infective coefficient β for interventions. The initial value of parameters was determined based on empirical data. The modeling was implemented using Matlab 7.1 software. Without interventions, the outbreak was expected to experience three phrases: (1) early stage (the first 5 days) in which the epidemic developed slowly and could be intervened easily; (2) rapid growing stage (6 - 15 days) in which the number of infected cases increased quickly and the epidemic could not be well controlled; and (3) medium and late stage (16 days and later) in which more than 90% of the susceptible persons were infected but the intervention measures failed to prevent the epidemic. With the implementation of interventions, the epidemic was predicted to be controlled in the early stage, under the SIR model. The simulation based on the SIR model kept an acceptable consistency with the actual development of epidemic after the implementation of intervention measures. The SIR model seemed effective in modeling interventions to the epidemic of acute hemorrhagic conjunctivitis in the schools.

Centers for Disease Control and Prevention (CDC). Notes from the field: acute hemorrhagic conjunctivitis outbreaks caused by coxsackievirus A24v --- Uganda and southern Sudan, 2010

CDC was contacted on June 22, 2010, by the Ugandan Ministry of Health (MoH)/Uganda Virus Research Institute and on July 11 by the Government of Southern Sudan (GOSS) via the CDC Global Disease Detection Regional Center in Kenya to perform diagnostic laboratory testing on conjunctival swabs from persons with "red eye syndrome." Widespread, ongoing outbreaks of acute hemorrhagic conjunctivitis (AHC) have been observed in Uganda and Southern Sudan since spring 2010. AHC becomes a reportable condition in outbreak settings. Case numbers were estimated in Uganda after MoH confirmation of reported cases from district health facilities and, in Southern Sudan, after a medical record review in six health facilities. To date, 6,818 cases from 26 districts in Uganda, and 428 cases in Juba, Southern Sudan, have been counted; however, because most cases are not reported, these totals are considered underestimates.

[Fruit of the emergence of an enterovirus: acute haemorrhagic conjunctivitis]

First seen in Ghana and Indonesia in the early 70's, acute haemorrhagic conjunctivitis or "Apollo 11" disease is an eye infection caused by Enterovirus type 70 (EV70). The disease appeared to be a highly contagious conjunctivitis which spread rapidly all over the world. EV70 has been considered as an emerging virus and was classified as a new Enterovirus. No human or animal virus genetically similar to EV70 was known before the sudden outcome of the disease in Ghana, West Africa. EV70 appeared as a pretty demonstrative example of virus emergence and virus spreading. Studies of virus genetic mutations emphasized the variations of RNA virus within a short time period. The current review presents the EV70 infection and the genetic profile of the virus from its emergence to nowadays.

Laboratory results in ocular viral diseases: implications in clinical-laboratory correlation

PURPOSE

To document etiology and predictive value of clinical diagnosis in laboratory confirmed viral diseases.

METHODS

Reports of culture-positive cases of samples collected from patients presenting from January 1987 - December 2001 were evaluated.

RESULTS

One thousand nine hundred and sixty-four (1964) cultures were submitted during 1987-2001. Twenty-six percent were positive (514). Human herpesvirus 1 was the most frequent agent isolated from all positive culture (56%). Adenovirus was the most common virus isolated from conjunctiva (66%), human herpesvirus 1 from lid and cornea (76%, 88%) and cytomegalovirus from vitreous (27%). Some unusual pathogens were recovered from conjunctiva as cytomegalovirus and from cornea as adenovirus, enterovirus and cytomegalovirus. Recognition of common viral syndromes was human herpesvirus 1 (88%), epidemic keratoconjunctivitis (88%), acute hemorrhagic conjunctivitis (70%) and varicella zoster virus (100%). However, some misdiagnosed cases were observed. Thirteen percent of conjunctivitis thought to be caused by herpes were due to adenovirus, 3.2% to Enterovirus, 3.2% to varicella zoster virus and 3.2% to human cytomegalovirus. Also, 5% of cases with a clinical diagnosis of herpes keratitis were caused by adenovirus and 2.7% by enterovirus. Finally, 4.8% of cases thought to be adenovirus conjunctivitis were herpes conjunctivitis.

CONCLUSIONS

Human herpesvirus 1 remains the most frequently isolated virus from ocular sites in general (56%). Nonherpetic corneal isolates were in decreasing order: adenovirus, enterovirus and cytomegalovirus. Clinical and laboratory correlation was less than 90%. The most misdiagnosed cases were herpes conjunctivitis and keratitis, some cases of adenovirus conjunctivitis some cases of acute hemorrhagic conjunctivitis. It is essential that a rapid and specific diagnosis is offered under atypical viral presentation for the institution of specific antiviral therapy and to avoid complications that can be a result of misdiagnosis and inappropriate treatment. Also it is important to do viral testing in order to confirm clinical diagnosis, report emerging infections, resistance and change in the epidemiology.

Rapid diagnosis of acute hemorrhagic conjunctivitis due to coxsackievirus A24 variant by real-time one-step RT-PCR

Coxsackievirus A24 variant is, together with enterovirus 70 and adenoviruses, the major etiological agent involved in acute hemorrhagic conjunctivitis outbreaks worldwide. However, the standard virus isolation method followed by serotyping or VP1 region sequencing is time-consuming. A rapid method for the detection of coxsackievirus A24 variant from conjunctival swab specimens would be useful in the context of explosive and extensive outbreaks. A one-step real-time RT-PCR assay based on TaqMan technology was thus developed and assessed on 36 conjunctival swabs from outbreaks of conjunctivitis in Morocco in 2004 due to a coxsackievirus A24 variant and in Corsica in 2006 due to adenovirus type 3, and 83 virus strains including 41 coxsackievirus A24 variant collected in French Guiana and Guadeloupe in 2003, in the Democratic Republic of the Congo in 2003, in Morocco in 2004 and 42 other virus species genetically close or known to be responsible for conjunctivitis. All the conjunctival swabs from coxsackievirus A24 variant related outbreak and the 41 coxsackievirus A24 variant strains were tested positive by the RT-PCR assay within 4h. This novel single-tube real-time RT-PCR assay is sensitive and specific, and consists in a reliable and faster alternative to the viral culture for recent and future acute hemorrhagic conjunctivitis outbreaks caused by coxsackievirus A24 variant.

An outbreak of acute haemorrhagic conjunctivitis in Melaka, Malaysia

This paper reports a second outbreak of acute haemorrhagic conjunctivitis due to coxsackievirus A24 in peninsular Malaysia. Between June 2002 and early October 2003, 10,327 patients, comprising 3,261 children and 7,066 adults, were treated for acute conjunctivitis in 11 government health clinics in the Melaka Tengah district of the state of Melaka. The figure grossly underestimates the size of the outbreak; as no patients treated in private clinics in the same district were included. Institution and household surveillance showed that the commonest presenting clinical feature of the illness was eye-discharge (91.2%), followed by foreign body sensation (81.8%), pain (78.3%) and subconjunctival haemorrhage (74.4%). The mean duration of illness was 6.5 and five days for patients with and without subconjunctival haemorrhage respectively.

Hemorrhagic viral keratoconjunctivitis in Taiwan caused by adenovirus types 19 and 37: applicability of polymerase chain reaction-restriction fragment length polymorphism in detecting adenovirus genotypes

PURPOSE

Acute keratoconjunctivitis with prominent subconjunctival hemorrhage (SCH) is usually perceived by a clinician as acute hemorrhagic conjunctivitis (AHC) associated with enteroviruses; however, SCH can also be an adenoviruses infection. A rapid and sensitive laboratory diagnosis is helpful for differential diagnosis. Therefore, the sensitivity and applicability of polymerase chain reaction (PCR) and reverse transcription (RT)-PCR diagnoses were evaluated for keratoconjunctivitis associated with viral infection.

METHODS

Conjunctival swabs from patients with acute conjunctivitis were tested using a PCR-restriction fragment length polymorphism (PCR-RFLP) for adenovirus detection and RT-PCR for enterovirus detection. The results were compared with those using the culture isolation and neutralization test; also, the clinical findings of the patients were analyzed with special attention to SCH patterns.

RESULTS

Neither coxsackievirus A type 24 variant (CA24v) nor enterovirus type 70 (EV70) was detected in 113 patients with acute conjunctivitis. The positive results of adenovirus (Ad) were 39.9% by the PCR method and 37.1% by culture isolation. For the patients with adenoviral conjunctivitis, 68.1% was owing to Ad37 and 19.2% was owing to Ad19. SCH was present in 51.5% of the positive cases, and 44.7% of the Ad-positive patients had secondary illnesses.

CONCLUSIONS

SCH can be a predominant presentation of Ad19 and Ad37 keratoconjunctivitis and may herald a new stage in the evolution of adenoviruses. PCR and PCR-RFLP are rapid and reliable methods for Ad detection and typing; however, if the amplified genes and restriction enzymes are not properly selected, they may not be able to detect new genotypes of adenoviruses or the evolution of these viruses.

Identification of a new strain of fastidious enterovirus 70 as the causative agent of an outbreak of hemorrhagic conjunctivitis

A 1994 outbreak of acute hemorrhagic conjunctivitis in Israel was caused by an enterovirus 70 strain that was distinct from previously reported strains. Characterization was by electron microscopy (eye washes), reverse transcription-PCR (RT-PCR; eyewash, specimens, eye swabs, and tears), and sequence analysis of RT-PCR-amplified fragments from the 5' noncoding region and VP1.

Detection of enterovirus 70 by polymerase chain reaction in acute hemorrhagic conjunctivitis

PURPOSE

We have developed and applied reverse transcription-polymerase chain reaction for the detection of enterovirus 70 from conjunctival swabs of patients among the population of an acute hemorrhagic conjunctivitis epidemic on Okinawa, Japan, in 1994.

METHODS

The primers used were selected from the VP1, VP2, and VP3 regions of the enterovirus 70 nucleotide sequence.

RESULTS

Twelve of 27 culture-negative specimens were positive by reverse transcription-polymerase chain reaction.

CONCLUSIONS

The reverse transcription-polymerase chain reaction test provides a reliable diagnostic method that readily allows specific detection of enterovirus 70 in patients with acute hemorrhagic conjunctivitis in whom low enterovirus 70 recovery rates have been obtained recently by cell culture.

[Acute hemorrhagic viral conjunctivitis]

Two cases of acute hemorrhagic conjunctivitis are described, in which the enterovirus Coxsackie 24 was found by serological examination to be the etiological agent. The virus was important from Nigeria. The patients suffered by the acute hemorrhagic keratoconjuntivitis with transient iritic irritation without the systemic symptoms. Since now this disease with serological verification was not diagnosed in our country. The question of the viral hemorrhagic conjunctivitis and their treatment is discussed. The necessity of virological investigation in inflammations of the anterior segment is stressed.

Acute hemorrhagic conjunctivitis

Acute hemorrhagic conjunctivitis, an infection caused by enterovirus 70 and a variant of coxsackievirus A24, is characterized by the rapid onset of severely painful conjunctivitis and subconjunctival hemorrhage. The condition is usually benign and resolves in five to seven days; however, a polio-like paralysis (radiculomyelitis) develops in approximately one in 10,000 patients infected with enterovirus 70. No treatment is available. Information about acute hemorrhagic conjunctivitis should be provided to patients and the community in order to prevent undue alarm, discourage home remedies and control the spread of this highly contagious disease.

[Rapid diagnosis of enterovirus 70 infection by detection of IgM antibodies with a biotin-avidin ELISA]

A biotin-avidin immunoassay was developed to detect IgM antibodies to enterovirus 70 (EV70) in sera from patients with acute hemorrhagic conjunctivitis. Biotinylated monoclonal antibody to EV70 and horseradish peroxidase-streptavidin were used in an indirect IgM capture ELISA. 40 acute- and convalescent-phase serum pairs were tested and 34 sera (85.0%) in the convalescent phase were positive for IgM antibodies. The positive rate of the method was much higher than that of the non-biotin-avidin system for EV70 (55%). Two sera in the acute phase, which were negative for neutralizing antibodies, had IgM antibodies. Two serum specimens which had been collected a third time from 2 patients during the seventh week after onset were positive for IgM, showing that EV70 IgM lasts at least for one month and a half. The biotin-avidin ELISA is sensitive and can be performed in 2 days instead of 3 days for the non-biotin-avidin method, and is useful for rapid diagnosis of EV70 infection.

[Study on rapid diagnosis of acute hemorrhagic conjunctivitis caused by Coxsackievirus A24 variant]

An pandemic of acute hemorrhagic conjunctivitis (AHC) caused by Coxsackievirus A 24 variant (CA 24v) occurred in China in 1988. Rapid diagnosis of AHC was investigated by immunofluorescence technique. The bacteria-free conjunctival swab samples were inoculated into HeLa cell monolayer. The Virus-specific antigens in infected cells were examined by indirect immunofluorescence test. Of 35 samples, 17 was identified as CA 24v. The results of isolation and typing could be obtained with in 5 days. Further, CA 24v antigen in infected conjunctival cells were examined by indirect immunofluorescence test. Of 48 smears of conjunctival cells, 39 was positive. Positive rate were 81.3%.

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.

The first epidemic of acute hemorrhagic conjunctivitis due to a coxsackievirus A24 variant in Okinawa, Japan, in 1985-1986

Epidemics of acute hemorrhagic conjunctivitis due to a coxsackievirus A24 variant occurred in July-November, 1985 and August-October, 1986 in Okinawa Prefecture, Japan. This is the first report of an acute hemorrhagic conjunctivitis epidemic due to a coxsackievirus A24 variant in Japan The epidemic involved most islands of the prefecture. The prefectural surveillance center was notified of 9,952 cases in 1985 and 6,096 cases in 1986 from three sentinel eye clinics. The neutralizing antibody-positive rate against the coxsackievirus A24 variant of the serum samples collected before and immediately after the 1985 epidemic rose from 1.0% to 8.5%. The coxsackievirus A24 variant was isolated from 48 out of 68 conjunctival swabs collected during the epidemics. The isolates were indistinguishable antigenically in the plaque reduction test from the prototype strain, EH24/70, but had a markedly distinct oligonucleotide pattern.

Diagnosis of enterovirus 70 infection by demonstration of IgM antibodies

Since outbreaks of severe acute hemorrhagic conjunctivitis occur worldwide [Hierholzer and Hatch, 1985] and the majority of the epidemics are caused by enterovirus 70 (EV-70), we developed an EV-70 IgM ELISA to simplify the diagnosis of these outbreaks. The test is based on the capture antibody technique and the use of monoclonal antibodies to EV-70. We detected EV-70 IgM antibodies in 55% of 76 convalescent-phase sera from an outbreak of acute hemorrhagic conjunctivitis in a Brazilian community. Among the 71 acute- and convalescent-phase serum pairs from this outbreak, 49 (69%) demonstrated a 4-fold or greater rise in neutralizing antibody-titer. The titer of IgM antibody began to drop by the fifth week after onset of illness. EV-70 IgM antibodies were not detected in 53 serum pairs with a 4-fold or greater rise in antibodies to other picornaviruses. The EV-70 ELISA proved to simple and relatively rapid to perform, appeared to be specific, and should be sensitive enough to diagnose outbreaks of EV-70 when multiple serum specimens can be tested.

[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.