An epidemiological model to aid decision-making for COVID-19 control in Sri Lanka

BACKGROUND: Sri Lanka diagnosed its first local case of COVID-19 on 11 March 2020. The government acted swiftly to contain transmission, with extensive public health measures. At the end of 30 days, Sri Lanka had 197 cases, 54 recovered and 7 deaths; a staged relaxing of the lockdown is now underway. This paper proposes a theoretical basis for estimating the limits within which transmission should be constrained in order to ensure that the case load remains within the capacity of Sri Lanka’s health system. METHODS: We used the Susceptible, Infected, Recovered (SIR) model to explore the number of new infections and estimate ICU bed requirement at different levels of R0 values after lifting lockdown restrictions. We developed a web-based application that enables visualization of cases and ICU bed requirements with time, with adjustable parameters that include: population at risk; number of identified and recovered cases; percentage identified; infectious period; R0 or doubling time; percentage critically ill; available ICU beds; duration of ICU stay; and uncertainty of projection. RESULTS: The three-day moving average of the caseload suggested two waves of transmission from Day 0 to 17 (R0 = 3.32, 95% CI 1.85–5.41) and from Day 18–30 (R = 1.25, 95%CI: 0.93–1.63). We estimate that if there are 156 active cases with 91 recovered at the time of lifting lockdown restrictions, and R increases to 1.5 (doubling time 19 days), under the standard parameters for Sri Lanka, the ICU bed capacity of 300 is likely to be saturated by about 100 days, signaled by 18 new infections (95% CI 15–22) on Day 14 after lifting lockdown restrictions. CONCLUSIONS: Our model suggests that to ensure that the case load remains within the available capacity of the health system after lifting lockdown restrictions, transmission should not exceed R = 1.5. This model and the web-based application may be useful in other low and middle income countries which have similar constraints on health resources

A simple intervention to prevent cutaneous larva migrans among devotees of the Nallur Temple in Jaffna, Sri Lanka.

BACKGROUND: A cross sectional study conducted during the annual festival at Nallur temple in Jaffna, Sri Lanka, in 2010, showed that the prevalence of cutaneous larva migrants (CLM) among the devotees who performed the side roll ritual was 58.2% (95%CI: 51.2%-65.0%). OBJECTIVE: To test the hypothesis that the deworming stray dogs around the temple premises effectively reduces the prevalence of CLM among devotees. METHODOLOGY/PRINCIPAL FINDINGS: All stray dogs (8) in the vicinity of the temple were treated, with mebendazole (100 mg) crushed and filled into sausages, 10 days before the commencement of festival in 2011. The same procedure was repeated a week later to ensure complete coverage. A cross-sectional study was conducted among 200 systematically selected devotees in August 2011 using an interviewer-administered questionnaire and the clinical examination of the skin. Baermann's technique was used for the recovery of nematode larvae from 40 soil samples collected from the temple premises. Ten samples of dog faeces collected from the same premises were also examined for nematode eggs. Prevalence of CLM among devotees in 2010 (Pre intervention) and 2011(Post intervention) were compared to test the hypothesis. Prevalence of CLM declined from 58% to 8% (Chi-square = 112.90, p<0.001) following the intervention. None of the subjects practiced new precautionary measures compared to the previous year. Soil and fecal samples were negative for parasites. CONCLUSIONS/SIGNIFICANCE: Regular dog deworming is an important and effective method for the prevention of CLM among the devotees doing side roll ritual and represents a pragmatic intervention that municipal authorities could perform on annual basis

Comparison of study population before and after intervention.

<p>Comparison of study population before and after intervention.</p

Outcome variables before and after intervention.

<p>Outcome variables before and after intervention.</p

Epidemiology and factors associated with amoebic liver abscess in northern Sri Lanka

Abstract Background Clinically diagnosed amoebic liver abscess (ALA) caused by Entamoeba histolytica has been an important public health problem in Jaffna district, northern Sri Lanka for last three decades. In order to draw up a control strategy for elimination of this condition, knowledge of its epidemiology and factors associated with this condition in the local context is vital. Methods All clinically diagnosed ALA patients admitted to the Teaching Hospital, Jaffna during the study period were included in the study and the data were collected using an interviewer administered questionnaire. One hundred blood samples from randomly selected toddy (a local alcoholic drink consisting of the fermented sap of the Palmyrah palm) consumers and 200 toddy samples were collected. Toddy samples were cultured in Robinson’s medium to establish the presence of Entamoeba histolytica in the sample. Climatic data and the total toddy sales in the district were obtained from the Meteorological and Excise Departments respectively. A sub group of randomly selected 100 patients were compared with 100 toddy consumers who were negative for E. histolytica antibody to explore the potential risk factors. Results Between July 2012 and July 2015, 346 of 367 ALA patients were enrolled in this study. Almost all patients (98.6%) were males with a history of heavy consumption of alcohol (100%). Almost all (94.2%) were within the age group 31–50 years. None of the cultured toddy samples grew E. histolytica. The monthly incidence of disease peaked in the dry season, matching the total toddy sales in the district. Age, type of alcohol and frequency of drinking were identified as potential risk factors whereas frequency of alcohol consumption and type of alcohol (consuming toddy and arrack) were identified as the independent risk factors. Moreover, the knowledge, attitude and practices towards ALA were poor among participants and the control group. Conclusions Though the number of cases has declined in recent years, ALA still remains as an important public health problem in Jaffna district. The transmission route of E. histolytica leading to ALA has to be further explored. Moreover, greater awareness among the public who are at risk would be beneficial in order to eliminate the disease