Sirimali Fernando

Dengue viral infections

Dengue viral infections are one of the most important mosquito borne diseases in the world. They may be asymptomatic or may give rise to undifferentiated fever, dengue fever, dengue haemorrhagic fever (DHF), or dengue shock syndrome. Annually, 100 million cases of dengue fever and half a million cases of DHF occur worldwide. Ninety percent of DHF subjects are children less than 15 years of age. At present, dengue is endemic in 112 countries in the world. No vaccine is available for preventing this disease. Early recognition and prompt initiation of appropriate treatment are vital if disease related morbidity and mortality are to be limited. This review outlines aspects of the epidemiology of dengue infections, the dengue virus and its mosquito vector, clinical features and pathogenesis of dengue infections, and the management and control of these infections.

Using the DREEM questionnaire to gather baseline information on an evolving medical school in Sri Lanka

The recent introduction of the Dundee Ready Education Environment Measure (DREEM) has fulfilled a long-felt need for a test instrument specifically meant to evaluate health professions education institutions. It was intended in this study to ascertain the overall DREEM score for the newly established Faculty of Medical Sciences of University of Sri Jayewardenepura (FMS/USJ), Sri Lanka and to compare the DREEM score of the students in the pre-, para- and clinical phases of the traditional curriculum practiced in this school. A total of 339 students belonging to the pre- (n = 147), para- (n = 116) and clinical (n = 76) phases of the medical course participated in this study. The DREEM questionnaire was administered face-to-face after one of their routine lectures to each group of students. The age of the students ranged from 20 to 28 years and the gender distribution was almost equal. The overall DREEM score was 108 (54%) for the pooled data for all three phases. There was no significant difference on the overall DREEM score obtained by each phase of students. The overall DREEM scores of pooled data and also for each domain indicated that the position of the FMS/USJ qualifies to be placed just on the third grade (one below the best) within the overall DREEM scale. However, on analysis of the responses for each domain, Students’ Perception of Teachers (SPT), Students’ Academic Self-Perceptions (SAP) and Students’ Social Self-Perceptions (SSP) showed significant difference between the pre-, para- and clinical phases. Similarly, 22 out of the 50 items showed significant differences between the pre- and clinical phases. Overall, the DREEM demonstrated compatibility of its scores along with the gradual development that took place at this medical school over the last 10 years. Thus, the DREEM could be utilized in a variety of situations.

Patterns of disease in Sri Lankan dengue patients

Background: Dengue is the most important mosquito borne viral infection in the world. Nearly 90% of infections occur in children. At present, prospective information on clinical and laboratory findings in South Asian children with dengue is generally lacking. Aim: To describe patterns of clinical disease in a cohort of children hospitalised with dengue during a major dengue epidemic in Sri Lanka. Results: A total of 104 children were studied during a three month period. Eighteen had dengue fever (DF) and 86 had dengue haemorrhagic fever (DHF). Of those with DHF, 34, 23, 27, and 2 had DHF grade I, II, III, and IV respectively. Based on dengue serology testing, 13 of the DF patients had a primary infection and 5 had secondary dengue infections. In contrast, 68 of the children with DHF had secondary and 18 had primary dengue infections. Oral candidiasis was seen in 19 children. The odds ratio for children with secondary dengue infection to develop DHF was 9.8 (95% CI 3.1 to 31.2). Conclusion: Studies on patterns of paediatric dengue disease in different regions should help clinicians and health administrators make more informed and evidence based health planning decisions. It should also help towards mapping out dengue trends on a global scale. Oral candidiasis has not been previously documented in children suffering with acute dengue in Sri Lanka or elsewhere. Studying underlying reasons for this manifestation during future dengue epidemics may provide useful leads in understanding overall dengue pathogenesis.

Seroprevalence of varicella zoster virus infections in Colombo District, Sri Lanka

BACKGROUND Although Varicella Zoster virus (VZV) infections occur worldwide, the epidemiology is remarkably different in tropical and temperate climates. VZV infections result in significant morbidity and mortality among adults in Sri Lanka. AIMS For future VZV vaccination strategies, we set to determine the age-specific seroprevalence rate of VZV infections in Colombo, Sri Lanka. MATERIALS AND METHODS The study was carried out from 1999 to 2000. Multi-stage cluster sampling technique was used to collect 913 blood samples, which were tested for the presence of VZV-specific IgG antibodies. RESULTS VZV seroprevalence rates were markedly lower in all age groups when compared to temperate climates. The seroprevalence rates increased with age in both the rural and urban populations. Of those aged 60 years, only 50% in the rural population and 78.9% in the urban population were immune to VZV. Seroprevalence rates of VZV infections were significantly different between the urban and rural populations (P< 0.001), with VZV-specific IgG antibodies detected in 47.5% in the urban population and 27.9% in the rural population. It was found that 56.2% (131) of females of childbearing age were nonimmune to VZV. CONCLUSIONS These findings highlight the need for a VZV vaccination program, which is likely to have a huge impact on the incidence of chickenpox and its associated morbidity and mortality.

Recombinant Multiepitope Protein for Early Detection of Dengue Infections

ABSTRACT Dengue fever is a mosquito-borne viral disease prevalent mainly in tropical countries. As the clinical manifestations of dengue are not very unique, laboratory diagnosis is crucial in identifying cases of dengue infection. Detection of dengue infection based on the identification of antidengue antibodies has emerged as a practical and reliable means of diagnosing dengue fever. We recently developed a customized recombinant dengue multiepitope protein (r-DME-G) that can specifically detect the immunoglobulin G (IgG) class of antidengue antibodies in patient sera. Using this strategy, we have now created another dengue multiepitope protein, r-DME-M, with specificity for the IgM class of antidengue antibodies. A synthetic gene encoding the r-DME-M protein was expressed as a maltose-binding protein fusion in Escherichia coli. The recombinant protein was purified in a single affinity chromatographic step to obtain yields of ∼15 mg purified protein/liter of culture. The purified protein was used to develop an in-house IgM enzyme-linked immunosorbent assay (ELISA) and tested using a panel of 172 patient sera characterized using the commercially available Dengue Duo rapid strip test from PanBio, Australia. The IgM ELISA results showed that the r-DME-M protein not only recognized all IgM+ samples identified by the PanBio test but also identified samples missed by the latter test. We also successfully adapted the r-DME-M protein to a rapid strip test format. This approach of creating customized antigens coupled to overexpression in E. coli and simple purification offers a promising alternative option to dengue diagnosis with the potential to circumvent the drawbacks of the whole virus antigen-based commercial kits.

HLA analysis of Sri Lankan Sinhalese predicts North Indian origin.

The origin of the Sinhalese population of Sri Lanka is debated. We subtyped HLA‐A*02 in 101 Sinhalese and observed a preponderance of the rare allele HLA‐A*0211 which was similar to reported frequencies in northern India. Taken with low‐resolution typing for the remaining A, B, C, DR and DQ alleles, these data suggest a North Indian origin for the Sri Lankan Sinhalese.