The impact of antigenic drift of influenza A virus on human herd immunity: Sero-epidemiological study of H1N1 in healthy Thai population in 2009

To examine the effect of the antigenic drift of H1N1 influenza viruses on herd immunity, neutralization antibodies from 744 sera from Thai healthy volunteers in 2008–2009, who had not been vaccinated for at least the last 5 years, were investigated by microneutralization (MN) and hemagglutination inhibition (HI) assays. Significantly higher MN titers were observed for the H1N1 Thai isolate in 2006 than in 2008. The results indicate that the antigenically drifted virus effectively escaped herd immunity. Since the low neutralization activity of herd immunity against drifted viruses is an important factor for viruses to spread efficiently, continuous sero-epidemiological study is required for public health.     

A rare case of primary sinonasal tuberculosis presented with phlyctenular keratoconjunctivitis in a pediatric patient: A case report and literature review

Rationale:Tuberculosis is a common cause of phlyctenular keratoconjunctivitis, especially for patients who live in a high endemic area of tuberculosis. We report a rare case of pediatric phlyctenular keratoconjunctivitis associated with primary sinonasal tuberculosis.Patient concerns:A 7-year-old boy presented with a 5-month history of redness of the left eye accompanied by mild visual impairment. Physical examination revealed elevated pinkish-white nodules with a circumcorneal hypervascularized lesion on the left conjunctiva.Diagnosis:Computed tomography revealed an enhancing soft tissue mass in the left maxillary sinus with bone destruction. Histopathology of maxillary tissue showed chronic inflammation without granuloma. Special stain, culture and polymerase chain reaction for mycobacterium were initially negative. Left maxillary sinus tuberculosis was diagnosed by positive Mycobacterium tuberculosis polymerase chain reaction from formalin-fixed paraffin-embedded maxillary tissue.Interventions:Two month of oral isoniazid, rifampicin, pyrazinamide, and ethambutol, followed by 10 months of oral isoniazid and rifampicin without topical eye drops agent were prescribed.Outcomes:Two months after initiation of treatment, the phlyctenular lesion had significantly improved. A follow-up computed tomography showed a significant reduction in the size of the maxillary sinus lesion and the extent of adjacent bone destruction.Lessons:Primary sinonasal tuberculosis is an uncommon cause of phlyctenular keratoconjunctivitis in children. When microbiological and histopathological evidences are absent, polymerase chain reaction analysis has a crucial role in the diagnosis of tuberculosis, especially in patient with uncommon presentation.     

Etiologies of central diabetes insipidus in Thai children

In order to determine the etiologies of central diabetes insipidus (DI) among Thai children, we retrospectively reviewed records of 67 patients (44 male and 23 female) between the age of 0.1 and 15.6 years (mean age 5.5 years) who were diagnosed with central DI at the Pediatric Endocrinology Unit, Siriraj Hospital, Bangkok, Thailand between 1996 and 2003. Etiologies were found to be central nervous system (CNS) malformations in 20 patients (29.8%), post resection of intracranial tumors and cysts in 17 patients (25.4%), intracranial tumors in 11 patients (16.4%), cerebral palsy of unknown cause in five patients (7.5%), infection in four patients (6%), and Langerhans cell histiocytosis in three patients (4.5%). In another seven patients (10.4%), the cause was considered to be idiopathic. This study revealed that CNS malformation was the most common etiology, followed by intracranial tumors and their treatment. A thorough investigation to rule out CNS lesions needs to be done before considering the diagnosis of idiopathic central DI.