Evaluation of biochemical and haematological changes in dengue fever and dengue hemorrhagic fever in Sri Lankan children: a prospective follow up study.

BACKGROUND: Series of biochemical and haematological changes occur during the course of dengue infection, which vary depending on the clinical disease. The patterns of change are not well documented and identifying these patterns in children with dengue infection would help to anticipate the progression to different clinical stages thus enabling effective management. METHODS: A prospective follow up study was conducted during the period of July 2013 - April 2014 at Professorial Pediatric unit, Lady Ridgeway Hospital for Children, Colombo, Sri Lanka. Children (5-12 years) admitted within the first 84 h of fever, with a clinical diagnosis of dengue infection were recruited. Children who became positive for dengue IgM were included in the final analysis. Blood was collected on admission for complete blood count, Alanine aminotransferase, Aspartate aminotransferase, albumin, cholesterol and corrected calcium. These tests were repeated at 12 hourly intervals during the hospital stay. RESULTS: Data of 130-subjects were analyzed (Dengue fever /Dengue hemorrhagic fever: 100/30). There was a significant difference in the pattern of white cell counts, platelets and haematocrit in the two clinical groups. Both transaminase rose initially in both dengue fever and dengue hemorrhagic fever and a steep rise were seen between 8th and 9th days in hemorrhagic fever. Both albumin and cholesterol decreased significantly at the time of entering into the critical phase. According to Receiver operating characteristic curve analysis, albumin level crossing 37.5g/L (sensitivity 86.7%, specificity 77.8%) and a 0.38 mmol/L reduction in cholesterol level (sensitivity 77.3%, specificity 71.9%) between day 3 and 4 were the best predictors of entering into critical phase. Calcium levels did not show any distinct pattern. CONCLUSIONS: There is a clear difference in the pattern of change of both hematological and biochemical parameters in dengue fever and dengue hemorrhagic fever. Reduction in albumin and cholesterol levels seen between the completion of day 3 and day 4 were highly valid predictors of entering into critical phase in dengue hemorrhagic fever.

Boosting of Mucosal Immunity After Fractional-Dose Inactivated Poliovirus Vaccine.

Background: Inactivated poliovirus vaccine (IPV) boosts mucosal immunity in persons previously vaccinated with oral poliovirus vaccine (OPV). We assessed whether fractional-dose IPV (fIPV, 1/5th of full dose) administered intradermally also boosts mucosal immunity. Methods: Children 10-12 years old were enrolled in Sri Lanka and randomized to receive one dose IPV, fIPV, or no IPV vaccine. One month later, they received OPV challenge. Blood was collected at enrolment and before challenge; stool was collected at 3, 7, and 14 days post-challenge. Sera were analysed for presence of poliovirus neutralizing antibodies; stool was analysed for poliovirus. Results: We analysed 304/309 (98%) enrolled subjects. There were 16/97 (16%), 9/99 (9%), and 72/95 (76%) subjects excreting poliovirus after challenge in the IPV, fIPV and "No IPV Vaccine" study arms, respectively (P < .001 for comparison of IPV [or fIPV] vs "No IPV Vaccine"; P = .1 for comparisons of fIPV vs IPV). Relative decrease in excretion prevalence was 80% and 88% to IPV and fIPV, respectively, compared with the "No IPV Vaccine" control arm. Conclusions: Single fIPV dose boosted mucosal immunity to a similar degree as single full dose of IPV. This finding provides further evidence in support of fIPV for poliovirus outbreak response at the time of IPV global supply shortage. Clinical trials registration: Australia New Zealand Clinical Trial Registry ACTRN12616000124437p.

Hantavirus Hemorrhagic Fever with Renal Syndrome - Suspected Cases in Sri Lanka: Clinical Picture and Epidemiology from 2013-2021.

Hantavirus hemorrhagic fever with renal syndrome (HFRS) is an emerging zoonotic disease in Europe and Asia, which is clinically indistinguishable from leptospirosis. A total of 1,032 patients with clinical suspicion of HFRS-like illness were included in the analysis from March 2013 to March 2021. Of these, 168 were positive for hantavirus immunoglobulin M (IgM) antibodies. Thirty-one of 35 patients had a 4-fold increase in IgG antibody titer with paired serum, confirming acute hantavirus infections. The detected antibodies showed a diverse pattern, strongly cross-reacting with the Seoul, Hantaan, and Puumala virus antigens. All the IgM-positive patients had no serological evidence of acute dengue or leptospirosis and had classical features of HFRS, including fever, thrombocytopenia, and renal involvement. More than 90% of patients had a history of rodent exposure 2-3 weeks prior to the onset of the fever. The highest number of positive cases was diagnosed in the Western and North Central Provinces of Sri Lanka during the paddy harvesting seasons. A significant number of patients develop severe complications with high mortality rates. Therefore, hantavirus infection should be considered as a differential diagnosis for leptospirosis-like illnesses in Sri Lanka.

New dengue virus type 1 genotype in Colombo, Sri Lanka.

The number of cases and severity of disease associated with dengue infection in Sri Lanka has been increasing since 1989, when the first epidemic of dengue hemorrhagic fever was recorded. We identified a new dengue virus 1 strain circulating in Sri Lanka that coincided with the 2009 dengue epidemic.

Serum chymase levels correlate with severe dengue warning signs and clinical fluid accumulation in hospitalized pediatric patients.

Dengue induces a spectrum of severity in humans from the milder dengue fever to severe disease, or dengue hemorrhagic fever (DHF). Chymase is a candidate biomarker that may aid dengue prognosis. This prospective study aimed to identify whether warning signs of severe dengue, including hypovolemia and fluid accumulation, were associated with elevated chymase. Serum chymase levels were quantified prospectively and longitudinally in hospitalized pediatric dengue patients in Sri Lanka. Warning signs were determined based on daily clinical assessments, laboratory tests and ultrasound findings. Chymase was significantly elevated during the acute phase of disease in DHF or Severe dengue, defined by either the 1997 or 2009 WHO diagnosis guidelines, and persisted longer in the most severe patients. Chymase levels were higher in patients with narrow pulse pressure and clinical warning signs such as severe leakage, fluid accumulation, pleural effusion, gall-bladder wall thickening and rapid haematocrit rise concurrent with thrombocytopenia. No association between chymase and liver enlargement was observed. This study confirms that serum chymase levels are associated with DHF/Severe dengue disease in hospitalized pediatric patients. Chymase levels correlate with warning signs of vascular dysfunction highlighting the possible functional role of chymase in vascular leakage during dengue.

Outbreak of severe acute respiratory infection in Southern Province, Sri Lanka in 2018: a cross-sectional study.

OBJECTIVES: To determine aetiology of illness among children and adults presenting during outbreak of severe respiratory illness in Southern Province, Sri Lanka, in 2018. DESIGN: Prospective, cross-sectional study. SETTING: 1600-bed, public, tertiary care hospital in Southern Province, Sri Lanka. PARTICIPANTS: 410 consecutive patients, including 371 children and 39 adults, who were admitted with suspected viral pneumonia (passive surveillance) or who met case definition for acute respiratory illness (active surveillance) in May to June 2018. RESULTS: We found that cocirculation of influenza A (22.6% of cases), respiratory syncytial virus (27.8%) and adenovirus (AdV) (30.7%; type B3) was responsible for the outbreak. Mortality was noted in 4.5% of paediatric cases identified during active surveillance. Virus type and viral coinfection were not significantly associated with mortality. CONCLUSIONS: This is the first report of intense cocirculation of multiple respiratory viruses as a cause of an outbreak of severe acute respiratory illness in Sri Lanka, and the first time that AdV has been documented as a cause of a respiratory outbreak in the country. Our results emphasise the need for continued vigilance in surveying for known and emerging respiratory viruses in the tropics.

Appropriate use of polymerase chain reaction for detection of herpes simplex virus 2 in cerebrospinal fluid of patients at an inner-city hospital.

Polymerase chain reaction (PCR) tests that detect herpes simplex virus (HSV) DNA in cerebrospinal fluid (CSF) are increasingly used to diagnose central nervous system (CNS) infections caused by HSV. To determine proper utilization of this test at an inner-city hospital, we performed a case-control study of adult patients, with HSV detected in CSF by PCR. Retrospective review of characteristics of adult patients hospitalized between 1997 and 2000 with CSF positive for HSV was done and compared to control patients with suspected CNS infection and negative CSF PCR. CSF from 1174 patients was tested; 20 (1.7%) had HSV DNA detected, 19/20 were HSV-2 and 1 was HSV-1. The HSV-2 cases were females (74%), with a median age of 41 years, of African-American ethnicity (100%). Of the cases, 90% had acute aseptic meningitis versus 13% controls (P < .001). Recurrent meningitis occurred in 42% cases and 3% controls (P < .001). CSF parameters significantly associated with HSV-2 positivity was lymphocytic pleocytosis (median leukocyte, 475 cell/mm3, 90% lymphocytes) (P < .001). In conclusion, HSV-1 was rarely detected in CSF of patients with suspected CNS infection. HSV-2 is more frequent, predominantly in young African-American women with lymphocytic aseptic meningitis, and is often recurrent. PCR testing for HSV-2 in CSF at inner-city hospitals can be greatly reduced by the application of these parameters.

Analysis of Dengue Serotype 4 in Sri Lanka during the 2012-2013 Dengue Epidemic.

The four serotypes of dengue virus (DENV-1, -2, -3, and -4) have had a rapidly expanding geographic range and are now endemic in over 100 tropical and subtropical countries. Sri Lanka has experienced periodic dengue outbreaks since the 1960s, but since 1989 epidemics have become progressively larger and associated with more severe disease. The dominant virus in the 2012 epidemic was DENV-1, but DENV-4 infections were also commonly observed. DENV-4 transmission was first documented in Sri Lanka when it was isolated from a traveler in 1978, but has been comparatively uncommon since dengue surveillance began in the early 1980s. To better understand the molecular epidemiology of DENV-4 infections in Sri Lanka, we conducted whole-genome sequencing on dengue patient samples from two different geographic locations. Phylogenetic analysis indicates that all sequenced DENV-4 strains belong to genotype 1 and are most closely related to DENV-4 viruses previously found in Sri Lanka and those recently found to be circulating in India and Pakistan.

Laboratory-Enhanced Dengue Sentinel Surveillance in Colombo District, Sri Lanka: 2012-2014.

INTRODUCTION: Dengue has emerged as a significant public health problem in Sri Lanka. Historically surveillance was passive, with mandatory dengue notifications based on clinical diagnosis with only limited laboratory confirmation. To obtain more accurate data on the disease burden of dengue, we set up a laboratory-based enhanced sentinel surveillance system in Colombo District. Here we describe the study design and report our findings of enhanced surveillance in the years 2012-2014. METHODS: Three outpatient clinics and three government hospitals in Colombo District that covered most of the Colombo metropolitan area were selected for the sentinel surveillance system. Up to 60 patients per week presenting with an undifferentiated fever were enrolled. Acute blood samples from each patient were tested by dengue specific PCR, NS1 ELISA and IgM ELISA. A sub-set of samples was sent to Duke-NUS Singapore for quality assurance, virus isolation and serotyping. Trained medical research assistants used a standardized case report form to record clinical and epidemiological data. Clinical diagnoses by the clinicians-in-charge were recorded for hospitalized cases. RESULTS: Of 3,127 febrile cases, 43.6% were PCR and/or NS1 positive for dengue. A high proportion of lab confirmed dengue was observed from inpatients (IPD) (53.9%) compared to outpatient (clinics in hospitals and general practice) (7.6%). Dengue hemorrhagic fever (DHF) was diagnosed in 11% of patients at the time of first contact, and the median day of illness at time of presentation to the sentinel sites was 4. Dengue serotype 1 was responsible for 85% of the cases and serotype 4 for 15%. The sensitivity and specificity of the clinicians' presumptive diagnosis of dengue was 84% and 34%, respectively. CONCLUSION: DENV-1, and to a lesser degree DENV-4, infection were responsible for a high proportion of febrile illnesses in Colombo in the years 2012 to 2014. Clinicians' diagnoses were associated with high sensitivity, but laboratory confirmation is required to enhance specificity.

Prevalence of prolonged and chronic poliovirus excretion among persons with primary immune deficiency disorders in Sri Lanka.

BACKGROUND: The Global Polio Eradication Initiative, established in 1988, has made substantial progress toward achieving this target, with only 3 countries never having eliminated wild poliovirus. Persons with primary immune deficiency disorders (PIDD) exposed to OPV are at increased risk of vaccine-associated paralytic poliomyelitis (VAPP) and of prolonged excretion of Sabin polioviruses. However, the risk for prolonged excretion is not known. Therefore, we studied the prevalence of PIDD with long-term poliovirus excretion in Sri Lanka, a middle income country currently using OPV. METHODS: We stimulated the referral of patients under the age of 35 years, with clinical features suggestive of immune deficiency to the single immunology clinic in the country, where these patients were investigated for the presence of PIDD. Stool samples from patients with PIDD were cultured for the presence of poliovirus (PV). Poliovirus isolates were tested for intratypic differentiation (ITD). The VP1 region of all poliovirus isolates was sequenced. RESULTS: Of 942 patients investigated, 51 (5.4%) were diagnosed with PIDD. Five (10.2%) patients excreted poliovirus. A patient with X linked agammaglobulinemia (XLA) excreted a mixture of all three Sabin like (SL) poliovirus serotypes. One patient with severe combined immune deficiency (SCID) excreted SL type 2, and another with SCID excreted SL type 3. One patient with SCID excreted a P2 vaccine-derived poliovirus (VDPV 2), and another with common variable immune deficiency (CVID) excreted a VDPV 3. The 3 patients with SCID died before scheduled collection of subsequent samples one month later, while the patient with XLA had cleared the virus in stool sample collected after 3 and 11 months. The CVID patient with VDPV 3 excreted for 7 months, and has developed a 23 nucleotide divergence in VP1 (∼900 nucleotides) from the parental Sabin virus. CONCLUSIONS: In our study, several patients with SCID, XLA and CVID excreted poliovirus. With improving health care quality patients with CVID and XLA may survive longer especially with provision of intravenous immune globulin. Regular screening of patients with PIDD for excretion of poliovirus is necessary to identify chronic excretors and make available specific therapies.

Histopathological diagnosis of myocarditis in a dengue outbreak in Sri Lanka, 2009.

BACKGROUND: In 2009, an outbreak of dengue caused high fatality in Sri Lanka. We conducted 5 autopsies of clinically suspected myocarditis cases at the General Hospital, Peradeniya to describe the histopathology of the heart and other organs. METHODS: The diagnosis of dengue was confirmed with specific IgM and IgG ELISA, HAI and RT-PCR techniques. The histology was done in tissue sections stained with hematoxylin and eosin. RESULTS: Of the 319 cases of dengue fever, 166(52%) had severe infection. Of them, 149 patients (90%) had secondary dengue infection and in 5 patients, DEN-1 was identified as the causative serotype. The clinical diagnosis of myocarditis was considered in 45(27%) patients. The autopsies were done in 5 patients who succumbed to shock (3 females and 2 males) aged 13- 31 years. All had pleural effusions, ascites, bleeding patches in tissue planes and histological evidence of myocarditis. The main histological findings of the heart were interstitial oedema with inflammatory cell infiltration and necrosis of myocardial fibers. One patient had pericarditis. The concurrent pulmonary abnormalities were septal congestion, pulmonary haemorrhage and diffuse alveolar damage; one case showed massive necrosis of liver. CONCLUSIONS: The histology supports occurrence of myocarditis in dengue infection.