Reduced dengue incidence during the COVID-19 movement restrictions in Sri Lanka from March 2020 to April 2021

Background

Dengue is the major mosquito-borne disease in Sri Lanka. After its first detection in January 2020, COVID-19 has become the major health issue in Sri Lanka. The impact of public health measures, notably restrictions on movement of people to curb COVID-19 transmission, on the incidence of dengue during the period March 2020 to April 2021 was investigated.

Methods

The incidence of dengue and COVID-19, rainfall and the public movement restrictions implemented to contain COVID-19 transmission were obtained from Sri Lanka government sources. A Seasonal Autoregressive Integrated Moving Average (SARIMA) model was used to predict the monthly dengue incidence from March 2020 to April 2021 for each of the country’s 25 districts based on five years of pre-pandemic data, and compared with the actual recorded incidence of dengue during this period. Ovitrap collections of Aedes larvae were performed in Jaffna city in the Jaffna district from August 2020 to April 2021 and the findings compared with similar collections made in the pre-pandemic period from March 2019 to December 2019.

Results

The recorded numbers of dengue cases for every month from March 2020 to April 2021 in the whole country and for all 25 districts over the same period were lower than the numbers of dengue cases predicted from data for the five years (2015–2019) immediately preceding the COVID-19 pandemic. The number of dengue cases recorded nationwide represented a 74% reduction from the predicted number of dengue cases for the March 2020 to April 2021 period. The numbers of Aedes larvae collected from ovitraps per month were reduced by 88.6% with a lower proportion of Ae. aegypti than Ae. albopictus in Jaffna city from August 2020 until April 2021 compared with March 2019 to December 2019.

Conclusion

Public health measures that restricted movement of people, closed schools, universities and offices to contain COVID-19 transmission unexpectedly led to a significant reduction in the reported numbers of dengue cases in Sri Lanka. This contrasts with findings reported from Singapore. The differences between the two tropical islands have significant implications for the epidemiology of dengue. Reduced access to blood meals and lower vector densities, particularly of Ae. aegypti, resulting from the restrictions on movement of people, are suggested to have contributed to the lower dengue incidence in Sri Lanka.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12726-8.

Augmented hamate replacement arthroplasty for fracture-dislocations of the proximal interphalangeal joints in 12 patients

We report clinical outcomes in 12 patients with hemi-hamate replacement arthroplasty combined with volar plate arthroplasty. The volar plate was reattached using trans-osseous sutures to reconstruct the ligament-box complex after hamate grafting to augment the stability of the proximal interphalangeal joint. Ten patients had improved joint movement from a mean of 14° before surgery to a mean of 77° at a minimum follow-up of 2 years. Grip strength and pain of the affected hand and patient-rated hand and wrist scores were improved in these 10 patients. Two patients had poor results. One patient developed ankylosis, and one patient had resorption of the grafted bone. We conclude that the augmented hamate replacement arthroplasty is useful in treating chronic proximal interphalangeal joint fracture-dislocations.

LEVEL OF EVIDENCE

IV.

Investigation of an Outbreak of Hepatitis A in a Coastal Area, Kerala, Southern India

An outbreak investigation was initiated following an unusual occurrence of hepatitis A reported among people residing in the coastal belt of Vadi to Vedikunnu area, Kollam district, Kerala, southern India. The time frame of disease occurrence, pattern of its distribution, and the incubation period of hepatitis A infection indicated the probability of occurrence of the outbreak as a result of pipe line water contamination due to mixing of sewage from a canal. The results add evidence to the epidemiology of hepatitis A in the state and warrant the establishment of an efficient water quality surveillance system.

Targeting self-renewal pathways in cancer stem cells: clinical implications for cancer therapy

Extensive cancer research in the past few decades has identified the existence of a rare subpopulation of stem cells in the grove of cancer cells. These cells are known as the cancer stem cells marked by the presence of surface biomarkers, multi-drug resistance pumps and deregulated self-renewal pathways (SRPs). They have a crucial role in provoking cancer cells leading to tumorigenesis and its progressive metastasis. Cancer stem cells (CSCs) are much alike to normal stem cells in their self-renewal mechanisms. However, deregulations in the SRPs are seen in CSCs, making them resistant to conventional chemotherapeutic agents resulting in the tumor recurrence. Current treatment strategies in cancer fail to detect and differentiate the CSCs from their non-tumorigenic progenies owing to absence of specific biomarkers. Now, it has become imperative to understand complex functional biology of CSCs, especially the signaling pathways to design improved treatment strategies to target them. It is hopeful that the SRPs in CSCs offer a promising target to alter their survival strategies and impede their tumorigenic potential. However, there are many perils associated with the direct targeting method by conventional therapeutic agents such as off targets, poor bioavailability and poor cellular distribution. Recent evidences have shown an increased use of small molecule antagonists directly to target these SRPs may lead to severe side-effects. An alternative to solve these issues could be an appropriate nanoformulation. Nanoformulations of these molecules could provide an added advantage for the selective targeting of the pathways especially Hedgehog, Wnt, Notch and B-cell-specific moloney murine leukemia virus integration site 1 in the CSCs while sparing the normal stem cells. Hence, to achieve this goal a complete understanding of the molecular pathways corroborate with the use of holistic nanosystem (nanomaterial inhibition molecule) could possibly be an encouraging direction for future cancer therapy.