Lymphatic filariases and soil-transmitted helminthiases in Sri Lanka: the challenge of eliminating residual pockets of transmission

Sri Lanka has successfully met the challenge of controlling both lymphatic filariasis (LF) and soil-transmitted helminthiases (STH) as public health problems. The primary public health strategy for combatting both conditions has been preventive chemotherapy. The national programme for the elimination of LF implemented five annual rounds of mass chemotherapy in the endemic districts from 2002 to 2006 using a combination of diethylcarbamazine and albendazole. The overall microfilaria rate declined from 0.21% in 2001 before the mass chemotherapy, to 0.06% in 2016, at declaration of elimination of LF as a public health problem by the World Health Organization. Currently Sri Lanka is in the phase of post-validation surveillance. Achieving control of STH has been more difficult. Mass deworming programmes have been implemented for nearly a century, and national-level surveys reported prevalence rates declining from 6.9% in 2003 to 1% in 2017. However, neither of these infections has been completely eliminated. A situation analysis indicates continued transmission of both among high-risk communities. This paper explores the reasons for persistence of transmission of both LF and STH in residual pockets and the measures that are required to achieve long-term control, or perhaps even interrupt transmission in Sri Lanka. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.

Clinical Exome Gene Panel Analysis of a Cohort of Urothelial Bladder Cancer Patients from Sri Lanka

BACKGROUND

Bladder cancer has a high rate of recurrence and high mortality rates in those who progress to muscle invasive disease. Biomarkers and molecular sub classification of tumours beyond standard histopathology has been proposed to address therapeutic dilemmas. The Cancer Genome Atlas project and other studies have contributed to the enhanced knowledge base of the mutational landscape of urothelial bladder cancer. Once again, these are mostly from Caucasian and Chinese patients, with data from the rest of Asia and Sri Lanka being sparse. The objective of this study was to assess the genomic variations of a cohort of urothelial bladder cancer patients in Sri Lanka.

METHODS

The molecular genetic study was conducted on formalin fixed paraffin embedded tumour samples of 24 patients, prospectively enrolled from 2013 to 2017. The samples were sequenced and variant distribution performed based on a 70-gene panel.

RESULTS

Total number of filtered mutations in the 24 patients was 10453. Median mutations per patient were 450 (range 22-987). The predominant mutational change was C>T and G>A. The top 5 mutated genes in our cohort were SYNE1, SYNE2, KMT2C, LRP2, and ANK2. The genes were clustered into 3 groups dependent on the number of mutations per patient per gene. The genes of cluster 1 and 2 mapped to Chromatin modifying enzymes and Generic Transcription Pathway. The chromatin remodelling pathway accounted for the largest proportion (22%) of mutations.

CONCLUSIONS

Clinical exome sequencing utilising a gene panel yielded a high mutation rate in our patients. The predominant mutational change was C>T and G>A. Three clusters of genes were identified. SYNE1 was the gene with the most mutations. The mutations comprised predominantly of genes of the chromatin remodelling pathway.

The association between steatosis and liver damage in transfusion-dependent beta thalassaemia patients

Non-alcoholic fatty liver disease (NAFLD) is a global health problem. Iron is the leading cause of liver damage in patients with transfusion-dependent thalassaemia (TDT), and data on the contribution of NAFLD to liver damage in TDT is lacking. Forty-five heavily transfused TDT patients who did not have biochemical or ultrasonic evidence of liver cirrhosis were evaluated for effects of iron overload, including the presence of diabetes mellitus, hypogonadism, serum ferritin, R2-MRI-liver, and liver enzymes alanine aminotransferase and aspartate aminotransferase. Liver fibrosis and steatosis were estimated using transient elastography (TE). Nine (20%) patients had significant steatosis (S1), and their body mass index (BMI) and liver fibrosis scores were higher than in patients without significant steatosis (S0) (p = 0.03 and p = 0.004, respectively). On regression analysis, the controlled attenuation parameter (CAP) score (i.e., degree of liver steatosis) was associated only with increasing BMI. The TE score (i.e., degree of liver fibrosis) was associated with increasing age, CAP score, male gender, and presence of diabetes. Neither liver steatosis nor fibrosis showed significant association with the liver iron concentration or iron-related organ damage (hypogonadism). In this cohort of TDT patients, steatosis of the liver, which is associated with increasing BMI, appeared to increase the risk of liver fibrosis.

Demographics, pathological characteristics and survival in urothelial bladder cancer in a cohort of Sri Lankan patients

Introduction

Bladder cancer has the 9th highest incidence among Sri Lankan males. This study describes the demographic profiles and survival in bladder cancer patients at two tertiary care centres in Sri Lanka.

Methods

A group of patients with urothelial bladder cancer, presenting for the first time for definitive treatment, were prospectively enrolled from 2013 to 2017.

Results

There were sixty-six patients, with median age of 65 years and male to female ratio of 7:1. Histopathologically pTa 24%, pT1 47% and pT2 29%. Of the pT1 tumours 61% were low grade (LG). The majority (71%) of non-muscle invasive bladder cancer (NMIBC) patients underwent transurethral resection of bladder tumour only. For the entire cohort the 5-year overall survival was 59% and cancer specific survival (CSS) was 65%. CSS in NMIBC was 75% and 30% in muscle invasive bladder cancer (MIBC). The 5-year female CSS (22%) was significantly lower than in males (71%).

Conclusion

Our cohort has a high male to female ratio. The percentage of MIBC was lower than reported in previous Sri Lankan studies. Of the pT1 tumours there is a higher percentage of pT1 LG patients in comparison to Western reports. There is low utilisation of intravesical mitomycin / bacillus Calmette-Guérin (BCG) in the treatment of NMIBC. The 5-year CSS in the Sri Lankan (lower middle-income economy) cohort lies between the values of high-income economies and upper middle-income economies in Asia. The reasons for poor CSS among Sri Lankan women with bladder cancer needs to be further investigated.

Prevalence and correlates of cognitive impairment in schizophrenia: a cross-sectional study from a teaching hospital southern Sri Lanka

INTRODUCTIONS

This study assessed the prevalence of cognitive impairment, the degree of impairment in individual cognitive domains and sociodemographic and clinical correlates among patients attending to psychiatry clinics at Teaching Hospital, Karapitiya, Sri Lanka.

METHODS

A cross-sectional study was carried out at the psychiatry outpatient clinics of Teaching Hospital, Karapitiya, Sri Lanka. Their cognitive functions were assessed using the culturally validated Sinhala version of Addenbrooke's Cognitive Examination - III (ACE-III-S). ACE-III-S score below 85.5 was considered as significant cognitive impairment. Linear regression analysis was used to assess the factors associated with cognitive impairment. A P value of 0.05 is considered significant.

RESULTS

One hundred forty patients with schizophrenia were assessed. Of this, 125 patients had significant cognitive impairment with a prevalence of 89.3% (95% CI:84.1-94.5). Impairment in each cognitive domain was as follows: 60% in attention, 65.7% in memory, 55% in fluency, 61.4% in language, and 63.6% in visuospatial skills. Impairment was not different between cognitive domains. Advancing age (P < 0.001), shorter duration of formal education (P = < 0.001), longer duration of illness (P = < 0.001) and not having a full-time employment (P = 0.020) showed a positive association with cognitive impairment.

CONCLUSIONS

Nine out of ten patients with schizophrenia experienced significant cognitive impairment. Patients showed more than 50% impairment in all cognitive domains. The cognitive domains did not show disproportionate impairment. This study highlights the importance of introducing routine cognitive assessment protocols in patients with schizophrenia.

A mechanistic model of snakebite as a zoonosis: Envenoming incidence is driven by snake ecology, socioeconomics and its impacts on snakes

Snakebite is the only WHO-listed, not infectious neglected tropical disease (NTD), although its eco-epidemiology is similar to that of zoonotic infections: envenoming occurs after a vertebrate host contacts a human. Accordingly, snakebite risk represents the interaction between snake and human factors, but their quantification has been limited by data availability. Models of infectious disease transmission are instrumental for the mitigation of NTDs and zoonoses. Here, we represented snake-human interactions with disease transmission models to approximate geospatial estimates of snakebite incidence in Sri Lanka, a global hotspot. Snakebites and envenomings are described by the product of snake and human abundance, mirroring directly transmitted zoonoses. We found that human-snake contact rates vary according to land cover (surrogate of occupation and socioeconomic status), the impacts of humans and climate on snake abundance, and by snake species. Our findings show that modelling snakebite as zoonosis provides a mechanistic eco-epidemiological basis to understand snakebites, and the possible implications of global environmental and demographic change for the burden of snakebite.

Revisiting the ATP 30: the Factor Structure of a Scale Measuring Medical Students' Attitudes Towards Psychiatry

OBJECTIVE

Among the scales developed for assessing medical students' attitudes regarding psychiatry, "attitude towards psychiatry-30" (ATP-30) is probably the most widely used. Although this scale was originally deemed to form a unitary dimension without any meaningful subscales, the authors sought to re-examine its factor structure and the viability of subscales.

METHOD

Secondary data from a survey of 743 final-year medical students from nine medical schools in Sri Lanka were analyzed using exploratory factor analysis (EFA) with promax rotation and confirmatory factor analysis (CFA), to assess the underlying factor structure of ATP-30. Parallel analysis was used in determining the number of factors to retain. Items conceptually external to the emerging factors were discarded.

RESULTS

Three models based on literature (one-, five-, and eight-factor) were disproved by CFA. A six-factor solution encompassing 18 items was supported by EFA and CFA and was gender-invariant. These factors were, namely, the image of psychiatrists, psychiatric patients and mental illness, the efficacy of treatment, psychiatric teaching, career choice, and psychiatry as an evidence-based discipline. While "the image of psychiatrists" formed the most consistent subscale (ω = 0.71), the internal consistencies of the other subscales were modest (ω = 0.55-0.67). The overall 18-item scale showed good internal consistency (ω = 0.78).

CONCLUSION

The findings provide evidence of a multi-dimensional structure in medical students' attitudes towards psychiatry, endorsing six meaningful subscales of the ATP-30. Future researchers and educators can utilize these subscales in identifying specific areas where students' attitudes are more stigmatized, to be intervened during undergraduate training.

Symptomatology of COVID-19 - Lessons from a meta-analysis across 13 countries

Background: COVID-19 pandemic has resulted in varying clinical manifestations and mortality rates. There is no consensus on the symptomatology that would guide researchers and clinicians. Aims and Objectives: The objective was to identify symptoms and their frequencies of COVID-19 with a meta-analysis of studies from several countries. Materials and Methods: Data sources: A systematic review using PubMed and Google Scholar data sources and reference tracing were used to identify 7176 articles. Eligibility criteria: Suitable articles were selected manually with selection criteria and 14 original articles included in meta-analysis. Data abstraction and analysis: PRISMA guidelines used for data abstraction and a table was generated by feeding it with numbers and proportions of each symptom described. A meta-analysis was carried out using random effect models on each symptom separately across the studies and their prevalence rates and 95% confident intervals were calculated. Results: Selected 14 studies, either cross-sectional or cohort studies are analyzed. There were 2,660 confirmed cases of COVID-19. The majority were from China (n=2,439, 91.7%) and remainder from the Netherlands, Italy, Korea, and India and one article from Europe. There were a total of 32 symptoms identified from the meta-analysis and additional 7 symptoms were identified from reference searching. The most common symptoms were (prevalence >50%): fever (79.56%, 95% CI: 72.17–86.09%), malaise (63.3%, 95% CI: 53.1–73.0%), cough (56.7%, 95% CI: 48.6–64.6%), and cold (55.6%, 95% CI: 45.2–65.7%). Symptoms of intermediate incidence (5–49%) were anosmia, sneezing, ocular pain, fatigue, sputum production, arthralgia, tachypnea, palpitation, headache, chest tightness, shortness of breath, chills, myalgia, sore throat, anorexia, weakness, diarrhea, rhinorrhea, dizziness, nausea, altered level of consciousness, vomiting, and abdominal pain. Rare symptoms (<5%): tonsil swelling, hemoptysis, conjunctival injection, lymphadenopathy, and rash. Conclusion: We found (25/32, from meta-analysis) symptoms to be present in ≥5% of cases which could be considered as “typical” symptoms of COVID-19. The list of symptoms we identified is different from those documents released by the WHO, CDC, NHS, Chinese CDC, Institute Pasteur and Mayo Clinic. The compiled list would be useful for future researchers to document a comprehensive picture of the illness.

Prevalence and predictors of new onset depression in the acute phase of stroke

INTRODUCTION

Post-stroke depression (PSD) is known to be associated with poor functional outcome and high mortality. There is limited data on the prevalence and associated factors of depression in the acute phase after stroke.

OBJECTIVES

To determine the prevalence of PSD in the acute phase and its correlates among patients with stroke in a tertiary care hospital in Sri Lanka.

METHOD

A cross sectional descriptive study was conducted among patients with stroke admitted to the stroke unit of a tertiary care hospital in Sri Lanka over a 3-year period. Demographic and clinical information was obtained using an interviewer administered questionnaire. Depression was diagnosed using the ICD-10 criteria. Group comparisons were performed using Pearson's Chi-square test and Mann-Whitney U test Multiple logistic regression was used to identify factors associated with PSD.

RESULTS

Of 374 patients, 106 patients experienced moderate to severe PSD, with a prevalence of 28.3 % (95 % CI: 23.8 %-32.9 %). Of them, 54.7 % were females, 49 % were above the age of 60 years, and 79.9 % had ischemic strokes. Female gender (OR-2.77, 95 % CI: 1.46-5.07, P = 0.002), a longer duration of hypertension (OR-1.31, 95 % CI: 1.01-1.721, P = 0.004), strokes involving the temporal lobe (OR-7.25, 95 % CI: 2.81-20.25, P < 0.001) and post-stroke functional disability (OR- O.98, 95 % CI:0.97-0.99, P = 0.001) were associated with PSD on multivariate analysis.

CONCLUSION

More than one fourth of the patients suffered from PSD in the acute phase of stroke. Female gender, longer history of hypertension, physical dependence and temporal lobe strokes were predictive of PSD.

BACKGROUND RADIATION LEVELS NEAR A MINERAL SAND MINING FACTORY IN SRI LANKA: CORRELATION OF RADIATION MEASUREMENTS WITH MICRONUCLEI FREQUENCY

Lanka Mineral Sands Ltd (LMS) is a company operating in Pulmoddai, Sri Lanka, mining for rare earth minerals along with monazite which contains thorium that emits ionizing gamma and alpha radiation on decay. The objective of the study was to determine the background radiation levels and selected radionuclides and then to correlate these levels with the frequency of micronuclei (MN) among persons residing in the vicinity of LMS. A cross-sectional study was conducted among persons of both sexes between 35 and 45 years of age residing in the vicinity of LMS. Background radiation measurements were obtained by a survey metre, and gamma spectrometry was done on soil samples. Five millilitres of venous blood was drawn for cytokinesis-blocked MN assay. Background radiation levels measured by the survey metre; 232Th, 226Ra and 210Pb mass activities in soil were highest in the samples collected from the LMS. The background radiation measurements positively correlated with MN frequency although the magnitude of the correlation was small (r = 0.176, p = 0.04). This implies that chronic long-term exposure to low-dose radiation may result in genotoxicity. Prospective large-scale studies are recommended to evaluate the long-term effect of exposure to low-dose radiation at Pulmoddai.

Comparison of liver MRI R2(FerriScan®) VS liver MRI T2* as a measure of body iron load in a cohort of beta thalassaemia major patients

To compare the similarity of the non-patented T2* and the high cost patented R2 (Ferriscan®) MRI techniques in the measurement of liver iron concentration (LIC) in heavily transfused patients with thalassaemia major in a real- life Sri Lankan hospital setup. We compared LIC measured by MRI, obtained 2 weeks apart, using both T2* and R2 techniques in 15 patients with beta thalassaemia major. They all had a history of > 100 units of blood transfusions life long and also a history of sub optimal chelation. MRI R2 and MRI T2* scan values showed a negative correlation (co-rrelation coefficient = − 0.63, p = 0.01) This correlation was strong in lower LICs and progressively decreased with upper LIC values. Thus a significant discrepancy was observed between median values of two MRI technologies (p = 0.0005) with T2* tending to underestimate iron overload especially in those with very high LIC identified by R2. The lack of concordance of T2* and R2 especially in those with very high reading on R2 suggest the potential errors in interpretations that can occur in “non-expert centres”; which are likely to lead to errors in clinical judgement on the intensity of chelation therapy needed.

High Prevalence of Overweight/Obesity in Urban Sri Lanka: Findings from the Colombo Urban Study

BACKGROUND

South Asian countries face a double burden of malnutrition characterized by high prevalence of underweight, overweight, and obesity. Understanding the distribution of this public health problem is important to tailor targeted interventions for communities. The objective of the current study was to find out the prevalence of obesity in urban Sri Lanka and to identify sociodemographic factors associated with it.

METHODS

Adult males and females residing in an urban government division of the Colombo District in Sri Lanka were included in this study (Colombo Urban Study). Stratified simple random sampling was used to select a sample of 463 from the total population. Sociodemographic data using an interviewer-administered questionnaire, anthropometric measurements, and serum samples were obtained for investigations.

RESULTS

When the global BMI cutoffs were applied, the community prevalences of underweight, normal weight, overweight, and obesity were 7.7%, 39.6%, 37.0%, and 15.8%, respectively. When the Asian BMI cutoffs were applied, the respective prevalences were 7.7%, 26.8%, 34.3%, and 31.2%. The community prevalence for abdominal obesity was 58.1% when using Asian cutoffs. Females had a higher prevalence of both obesity and abdominal obesity. There was an ethnic difference in obesity rates with Moors having the highest rates (65.5%) followed by Sinhalese (52.3%) and Tamils (40.2%). The highest obesity prevalence was observed in the most educated group. Multiple regression analysis showed that high BMI was associated with female gender and family history of hypertension. Serum LDL negatively associated with BMI while the strength of this relationship was impacted by serum HBA1c levels. Finally, serum triglyceride level showed positive association with BMI, and the effect was more marked in Moors compared to Sinhalese.

CONCLUSION

Two-thirds of adults in the studied urban population were overweight or obese. This highlights the urgent need for interventions to curb this epidemic. The gender, ethnic differences in obesity, its associations with educational status, and the interactions with metabolic comorbidities indicate that these interventions may need to be targeted towards different groups in the population.

Morphological variations of the human ejaculatory ducts in relation to the prostatic urethra

Loss of ejaculation can follow transurethral resection of the prostate (TURP). Periverumontanal prostate tissue is preserved in ejaculation-preserving TURP (ep-TURP). Knowledge of ejaculatory duct anatomy in relation to the prostatic urethra can help in ep-TURP. This was evaluated in cross-sections of the prostate using a 3 D model to determine a safe zone for resecting the prostate in ep-TURP. A 3 D reconstruction of the ejaculatory ducts was developed on the basis of six prostate gland cross-sections. The measurements obtained from the 3 D model were standardized according to the maximum width of the prostate. Simple linear regressions were used to predict the relationships of the ejaculatory ducts. The maximum widths of the prostates ranged from 22.60 to 52.10 mm. The ejaculatory ducts entered the prostate with a concavity directed posterolaterally. They then proceeded toward the seminal colliculus in a fairly straight course, and from that point they angulated anteromedially. As they opened into the prostatic urethra they diverged. Significant regression models predicted the relationships of the ejaculatory ducts to the prostatic urethra based on the sizes of the prostates. The 3 D anatomy of ejaculatory ducts can be predicted on the basis of prostate width. The ejaculatory ducts can be preserved with 95% accuracy if a block of tissue 7.5 mm from the midline on either side of the seminal colliculus is preserved, up to 10 mm proximal to the level of the seminal colliculus, during TURP. Clin. Anat. 31:456-461, 2018. © 2017 Wiley Periodicals, Inc.

Association of Serum Ferritin with Diabetes and Alcohol in Patients with Non-Viral Liver Disease-Related Hepatocellular Carcinoma

INTRODUCTION

Non-alcoholic fatty liver disease is a leading cause for hepatocellular carcinoma (HCC) in Sri Lanka. Diabetes mellitus, alcohol abuse, and liver inflammation are known to increase the risk of HCC. The present study evaluates serum ferritin levels in a cohort of patients with non-viral HCC (nvHCC).

METHODOLOGY

Consecutive patients with nvHCC presenting to the Colombo North Liver transplant Service, Ragama, from January 2012 to July 2013 were investigated. All were negative for hepatitis B and C. At registration, 5 mL of serum was separated into plain tubes, stored at -80°C and analysed for ferritin using an enzyme-linked immunosorbent assay. Correlation between the serum ferritin and patient risk factors, liver status, and tumour characteristics were analysed.

RESULTS

There were 93 patients with nvHCC (median age 65 [12-82] years; 82 [88.2%] males). The median ferritin level was 246.2 μg/L, and 38 (40.86%) patients had elevated ferritin. Non-diabetics (median 363.5 mg/L, p = 0.003) and alcohol abusers (median 261.2 mg/L, p = 0.018) had higher ferritin levels. On multiple-variable analysis, being non-diabetic (p = 0.013) and alcoholic (p = 0.046) was significantly associated with high serum ferritin. No association was found with body mass index, tumour stage, size, macrovascular invasion, number of nodules, alpha-fetoprotein, bilirubin, international normalized ratio, and survival.

CONCLUSION

In patients with nvHCC, serum ferritin levels are higher in non-diabetics and alcoholics.

A randomized, double-blind, placebo-controlled trial on the role of preemptive analgesia with acetaminophen [paracetamol] in reducing headache following electroconvulsive therapy [ECT]

BACKGROUND

Electroconvulsive therapy (ECT) is a safe and efficient treatment for several severe psychiatric disorders, but its use is limited by side effects. Post-ECT headache is one of the commonest side effects. Preemptive analgesia is effective in post-surgical pain management. The most commonly used analgesic is acetaminophen (paracetamol). However, acetaminophen as a preemptive analgesic for post-ECT headache has not been studied adequately. This study was conducted to compare the incidence and severity of post-ECT headache in patients who were administered acetaminophen pre-ECT with a placebo group.

METHODS

This study was a randomised, double-blind, placebo-controlled trial. Sixty-three patients received 1 g acetaminophen and 63 patients received a placebo identical to acetaminophen. The incidence and severity of headache 2 h before and after ECT were compared between placebo and acetaminophen groups. The severity was measured using a visual analog scale. Generalised linear models were used to evaluate variables associated with post ECT headache.

RESULTS

Demographic and clinical variables of placebo and acetaminophen groups were comparable except for the energy level used to induce a seizure. Higher proportion of the placebo group (71.4%) experienced post-ECT headache when compared to the acetaminophen group (p < 0.001). The median pain score for headache was 0 (Inter quartile range: 0-2) in acetaminophen group whereas the score was 2 (IQR: 0-4) in placebo group (P < 0.001). Model fitting showed that the administration of acetaminophen is associated with less post-ECT headache (odds ratio = 0.23, 95% CI: 0.11-0.48, P < 0.001).

CONCLUSION

A significant reduction was seen in both the incidence and severity of post-ECT headache with preemptive analgesia with acetaminophen.

TRIAL REGISTRATION

Ethical approval was granted by an Ethic review committee, University of Kelaniya, Sri Lanka (P/166/10/2015) and the trial was registered in the Sri Lanka Clinical Trials Registry ( SLCTR/2015/27 ).

Seroprevalence of Bordetella pertussis specific Immunoglobulin G antibody levels among asymptomatic individuals aged 4 to 24 years: a descriptive cross sectional study from Sri Lanka

Background

In Sri Lanka pertussis continues to circulate in the community and cases among adolescents and adults have been reported despite 95% coverage of the four dose pertussis vaccination during early childhood. Waning of immunity following natural infection or immunization may contribute to the persistent circulation. An adolescent booster dose is not included in the national immunization schedule of Sri Lanka, although this is routine practice in many countries. Therefore information on immunity to pertussis in the adolescent group is needed prior to considering vaccination schedule changes.

Methods

The quantitative determination of specific Immunoglobulin G antibodies to Bordetella pertussis toxin was done using a commercially available validated ELISA method. The antibody values were categorized into groups according to the interpretive criteria provided by the manufacturer. The values were <55 IU/mL, negative; 55–<60 IU/mL, borderline; 60–125 IU/mL, positive; >125, strongly positive respectively. Sera of 385 asymptomatic individuals aged 4 to 24 years admitted to surgical units of Lady Ridgeway Hospital, Colombo and Colombo South Teaching Hospital were used for the study. Mann-Whitney U and Kruskal-Wallis tests were used in analysis of results and p ≤0.05 was considered as statistically significant. Details of epidemiological variables were collected using a questionnaire and correlation with significant levels of pertussis antibodies was determined.

Results

Median age of the study population was 12 years with 212 (55.1%) females. The median anti PT antibody level was 3.31 IU/mL and 352 (91%) had anti PT levels ≤55 IU/mL. Median of anti PT levels were 3.18 IU/mL for 4–7 years, 1.43 IU/mL (IQR 0.336–6.27) for 8–11 years, 4.28 IU/mL (IQR 0.978–13.39) for 12–15 years, 6.14 IU/mL for 16–19 years and 4.89 IU/mL for 20–24 years and the differences were statistically significant (p = 0.000). Females (p < 0.003) and those having a sibling aged ≥12 years (p = 0.017) had significantly higher anti PT levels.

Conclusions

The majority of the study population, especially 8 to 11 year age group had low anti PT IgG levels. The higher antibody titers in the 12–15 year age group seem to indicate infection in early adolescence. A booster dose of acellular pertussis vaccine need to be considered.