Spatial distribution and risk factor assessment for dengue transmission with a WhatsApp based health literacy intervention for risk reduction in an endemic district of coastal Karnataka

Objectives:

1. To determine the socio-behavioural and environmental risk factors for dengue

transmission among population in an endemic district of coastal Karnataka.

2. To map the spatial distribution of dengue cases and entomological indices

3. To study the clinical presentation, outcomes and out of pocket expenditure in

patients with dengue fever

4. To evaluate the effectiveness of a WhatsApp-based health literacy intervention for

dengue risk reduction

Methodology

Objectives 1, 2 & 3:

Study Design:

A community-based cross-sectional study will be conducted in Malpe area of Udupi

taluk from May 2024 to March 2025.

Study Setting:

Malpe, located in Udupi district, Karnataka, has a population of 29,854 spread

across six subcentres. Known for its tropical climate and high prevalence of vector-

borne diseases like malaria and dengue.

Study Subjects:

Residents of Malpe, Udupi taluk, who have lived in the area for at least one year.

Inclusion Criteria:

Residents aged ≥18 years willing to provide information about their family and

household characteristics.

Sample Size Estimation:

Based on study by Kamath et al (2012) 5, carried out in Udupi taluk, proportion of

water containers inside houses was found to be 20%, at 95% confidence level with a

15% relative precision and 10% non-response rate, estimated sample size is 782

households.

Probability proportional to size technique will be used to ensure representativeness

of population from all the subcentres under primary health centre of Malpe. In each

subcentre the first household will be selected randomly and will be moved in a

particular direction till the sample size is reached.

Data Collection Methodology:

Ethical approval will be obtained from the Institutional Ethics Committee. Informed

consent will be obtained from all participants. Using a pretested semi-structured

questionnaire, socio-demographic factors, housing and environmentalcharacteristics, knowledge and practices related to dengue disease and vector

characteristics will be collected. Potential breeding sites (larvae & pupae) and vector

control practices will be evaluated using checklist.

Objective 3:

Methodology:

Among households surveyed, any member with a history of lab-confirmed dengue

fever in the past year will be interviewed regarding symptoms, complications,

hospitalization history, and out-of-pocket expenses for disease management.

Objective 4:

Study Design:

A quasi-experimental study with pretest-post-test design will evaluate effectiveness

of a WhatsApp-based health literacy intervention for dengue risk reduction over three

months.

Study Subjects:

Residents of Malpe area who participated in cross-sectional study and meet

inclusion criteria (≥18 years, smartphone users with regular WhatsApp access).

Sample Size:

To expect an improvement of at least 16% (George LS et al,6) in vector prevention

practices postintervention, assuming 95% CI with 10% allowable error, the sample

size estimated for the study is 60, which is inclusive of 10% loss to follow-up. Further

an equal number of participants (household) will be selected across the subcentres.

Data collection methodology and Intervention Details:

A written informed consent will be obtained the intervention will be provided through

WhatsApp individually. Health literacy intervention will highlight Clinical features,

complications, mode of transmission of dengue, vector responsible and its

characteristics and various measures to reduce the transmission.

Video intervention will be given at baseline and at end of first and second month with

little modification in the intervention. The intervention will use images & videos

available with district (IEC materials) and inputs from faculty community medicine and

district vector borne disease control officer and team with validation from experts.

Intervention will be shared with participants privately and as well as a WhatsApp

group. The participants will be followed up at end of three months with postintervention

questionnaire to assess for any change in the knowledge and practices regarding

dengue and vector control practices.