Acute hemorrhagic conjunctivitis outbreak in Thailand, 1992

Acute hemorrhagic conjunctivitis remains a public health concern due to its rapid spread and potential for large outbreaks. Prior research has shown that enteroviruses, especially coxsackievirus A24 variant, are frequently associated with such outbreaks. However, the exact clinical and virological features of these outbreaks in specific regions remain understudied. This gap motivated the need for localized investigations to better understand the disease's presentation and transmission. In Thailand, outbreaks have occurred historically, but detailed clinical data from 1992 were lacking. The short incubation period and sudden onset of symptoms suggest a highly contagious agent. No prior work had resolved the specific contribution of CA24v in this particular outbreak. Understanding the frequency of mucopurulent discharge and subconjunctival hemorrhage could guide treatment and prevention strategies. This study aimed to clarify the virological and clinical profile of the 1992 Thai outbreak.

The study aimed to analyze the clinical and virological features of acute hemorrhagic conjunctivitis in a 1992 outbreak in Thailand. Researchers focused on identifying the causative agent and characterizing the disease's progression. The motivation stemmed from the need to document the outbreak's impact and inform public health responses. The study sought to determine the prevalence of coxsackievirus A24 variant among affected individuals. Researchers also aimed to assess the effectiveness of diagnostic methods such as conjunctival and throat swabs. The short duration of symptoms suggested a self-limiting nature, but the presence of neurological complications raised concerns. The study's design allowed for the collection of both clinical and virological data. This approach enabled a comprehensive understanding of the outbreak's characteristics.

Researchers examined 260 cases of acute hemorrhagic conjunctivitis at Siriraj Hospital between October and December 1992. Clinical and virological data were collected from each patient. Conjunctival and throat swabs were used to isolate the causative agent. Neutralizing antibody titers were measured in a subset of patients. The study design allowed for the comparison of isolation rates between swab types. Clinical features such as lacrimation and periorbital pain were recorded. The presence of subconjunctival hemorrhage and preauricular lymphadenopathy was documented. The study also tracked the occurrence of neurological complications in affected individuals.

Coxsackievirus A24 variant was detected in 76.8% of 95 tested cases. Conjunctival swabs had a higher isolation rate at 68.2% compared to throat swabs at 32.8%. A four-fold rise in neutralizing antibody titer was observed in 59.5% of 42 cases. The disease had a short incubation period and resolved within 5 days in most patients. Bilateral involvement was common, with 48% of eyes showing mucopurulent discharge. Subconjunctival hemorrhage occurred in 10.1% of affected eyes. Preauricular lymphadenopathy was present in 16.2% of cases. Only one patient developed neurological complications, including facial palsy lasting three months.

The study demonstrated that coxsackievirus A24 variant was the primary agent in the 1992 Thai outbreak. The high isolation rate from conjunctival swabs suggests their utility in diagnosis. The disease's self-limiting nature was confirmed, with most cases resolving within 5 days. The presence of mucopurulent discharge and subconjunctival hemorrhage was notable. Bilateral involvement was common, indicating a high degree of viral spread. Neurological complications were rare but severe in the one documented case. The study's findings support the need for continued surveillance of similar outbreaks. These results align with previous reports of CA24v-associated conjunctivitis in other regions.