RGUHS Nat. J. Pub. Heal. Sci Vol No: 9 Issue No: 1 eISSN: 2584-0460 pISSN:
Iswarya P1 , Ranganath T S2 , Riya George1 , Vinay Kumar Ganesh Hegde1
1: Postgraduate, BMCRI, Bengaluru 2: Professor and Head of the department, Department of community medicine, Bangalore Medical College and Research Institute, Bengaluru.
*Corresponding author:
Iswarya P, Postgraduate, BMCRI, Bengaluru. Department of community medicine, Bangalore Medical College and Research Institute, Bengaluru. E-mail: ispaa2010@gmail.com
Received: April 5, 2022; Accepted: May 5, 2022; Published: June 30, 2022
Abstract
Background and Objectives: Dengue is one of the major mosquito-borne diseases in India, posing a threat to human health. The mosquito Aedes (Stegomyia) aegypti (Linn.) and Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae), are the primary and secondary vectors of dengue virus, respectively. This study is aimed at the assessment of Dengue breeding in slum areas of urban Bengaluru.
Methodology: In this study, an entomological survey was carried out indoors and outdoors to record the actual breeding sites and distribution level of dengue vectors. The survey was conducted in the field practice area of Bangalore Medical College, India. A total of 9782 containers with water from 4869 houses were surveyed during the study period.
Results: The larval indices were calculated in each sector belonging to the field practice area, of which sector 2 was the highest which had a house index of 4.9%, container index of 2.8%, and Breteau index of 5.7%.
Conclusion: The most frequently encountered breeding sites were unused grinding stones, flower pots, drums, barrels, rubber tires, and cement tanks.
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Introduction
Dengue fever (DF) is one of the important mosquitoborne, viral infectious diseases; distributed in tropical and subtropical regions of the world. DF has become an extremely significant public health problem threatening many lives.1,2 It is reported that 50–200 million DF clinical cases occur annually in over 125 countries3 and 50% of the world’s population is at risk of DF4-5. The day-biting mosquitoes such as Aedes aegypti L. and Aedes albopictus are adapted to breed in domestic and peri-domestic areas. The major breeding site of these two vector mosquitoes is man-made containers7 . Rapid urbanization, abiotic conditions, and climate change influence the breeding of these two species8 . Further more, the stable coexistence of Ae. aegypti with Ae. albopictus in an area may lead to an expansion of both the species and result in a higher dengue transmission rate.
Objectives
To assess the Ae. larval indices and the breeding habitats in the urban slums of field practice of Bangalore Medical College.
Materials and methods
The present study is an observational study conducted in the urban slums of the field practice of Bangalore Medical College belonging to H. Siddaiah road UHTC. It is classified under ward 118 of Bengaluru BBMP. The field practice area is divided into 3 sectors with an ANM (Auxillary Nurse Midwife) for each sector.
Sector 1 comprises the following areas: Ramanna Garden, Vinobha Nagar, and Muniyappa Compound. Sector 2 comprises CKC garden and KS garden and Sector 3 comprises HK Garden, AJ Garden, Shambupalya, and RG Garden. The entomological survey was conducted in the above-mentioned areas from March 2022 to April 2022; outdoors and indoors. The houses were selected by random sampling method for larva and the indices were calculated. The houses in which people were present were surveyed indoors and outdoors whereas the houses which were locked were surveyed for larva outdoors only. All the containers, barrels, grinding pots, and all artificial water storage areas were surveyed. Data were collected and entered into an MS Excel sheet and analyzed for descriptive statistics.
Results
In the present observational study, 4869 houses were surveyed and 9782 containers were collected. Among the houses surveyed, 66% (N=3213) were pucca houses and the remaining 34% (N=1656) were kutcha houses.
The Ae. immature indices were calculated as per the formula suggested by World Health Organization (WHO)9
House Number of houses found positive / Number of houses surveyed x100
Index (HI) =
Container Number of containers found positive / Number of wet containers surveyed x100
Index (CI) =
Breteau Number of containers found positive / Number of houses surveyed x 100
Index (BI)=
Discussion
Aedes mosquitoes breed profusely in all types of waterstoring containers. The recent sporadic rain in many places of Karnataka including Bengaluru City10 has fuelled the rise of the Ae. mosquito population and the number of positive containers for larvae/pupae. The rise in the vector density of dengue and the transovarial transmission would result in fast dengue virus transmission. This further leads to a massive increase in dengue cases.11
There are continuous warnings from health experts including WHO that malaria deaths in Sub-saharan Africa doubled due to the absence of malaria control activities during COVID-19. To contain the spread, indoor residual spray (IRS) and a few other malaria control activities were recommended.12-14 With an innovative and skillful approach, dengue transmission can also be contained. Breeding with the help of drones (unpiloted small aircraft) can be monitored and insecticides can be sprayed. Sensitizing the public on dengue control through television, radio, local newspaper, and social media for taking dengue preventive measures. These preventive measures include reducing the breeding sources in the premises of the house and backyards, wearing protective clothes while using mosquito repellents, and using bednets during daytime sleep.
Conclusion
Continued dengue vector surveillance and strengthening vector control interventions are essential. Field-level health staffs need to be trained to confirm their safety and take efforts to minimize and prevent dengue transmission in any future outbreaks. The present study observed high larval indices in the surveyed areas in the Bengaluru City of India. The Ae. HI, CI, and BI were observed to be slightly increased. This shows that the dengue virus transmission may increase in the coming days. Therefore, it is highly recommended to adopt innovative methods like finding breeding grounds and larviciding with insecticides using drones. Sensitizing the public simultaneously through television, radio, local newspaper, and social media to prevent any future dengue outbreaks.
Conflicts of Interest
None
Supporting Files
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