D589 Task 1 Disease Prevention Strategy Example

From a Traveler's Fever to a Neighbor's Infection: Causes, Data Sources and a Community Education Strategy for Locally Acquired Dengue in a Composite Gulf Coast County

Student Name

Leavitt School of Health, Western Governors University

D589: Chronic and Infectious Diseases, Task 1

Course Instructor

Month Day, Year

From a Traveler's Fever to a Neighbor's Infection: Causes, Data Sources and a Community Education Strategy for Locally Acquired Dengue in a Composite Gulf Coast County

The Disease and Why It Is Emerging

Dengue is a viral infection spread mainly by the Aedes aegypti mosquito. Most infections cause no symptoms or a flu-like illness with fever, severe body aches and rash, but a small share progress to severe dengue with bleeding and shock, and a second infection with a different type of the virus raises that risk. For most of the past century, dengue in the continental United States was a disease of returning travelers. That is changing. During May 2022 to April 2023, Florida identified 601 travel-associated and 61 locally acquired dengue virus type 3 infections, and genetic sequencing showed that most local cases occurred shortly after introductions from travelers, with little sustained transmission (Jones et al., 2024).

Palm Hollow County is a composite Gulf Coast county of about 300,000 people with frequent travel to and from the Caribbean and Latin America. Last year it recorded 118 travel-associated cases and 14 locally acquired cases, its first local cases in a decade. This paper discusses the causes and effects of dengue in the county, identifies reputable data sources and develops a community education strategy for prevention and control.

Causes and Impacts

Local transmission requires three things to meet: an infected person, a mosquito that can carry the virus and enough contact between them. Travel supplies the first. The Aedes aegypti mosquito, which bites during the day and lays eggs in small containers of standing water around homes, supplies the second; it thrives in the county's warm, humid climate, and longer warm seasons extend its active period. The third is shaped by housing and behavior: homes without screens or air conditioning, yards with buckets, plant saucers, tires and clogged gutters, and daytime outdoor work.

The impacts reach beyond illness. Each local case triggers an investigation, door-to-door mosquito control and public notices. Severe cases require hospital care, and an outbreak can affect tourism and local business. Because Aedes aegypti also spreads Zika and chikungunya, the conditions that allow dengue transmission create risk for other diseases as well.

Reputable Data Sources

Four sources inform the county's picture, and each has limits.

National arboviral surveillance. States report confirmed and probable dengue cases to a federal surveillance system, which allows comparison across states and years. It relies on clinicians testing and reporting, so mild cases that never reach a doctor are missed, and reports can lag by weeks.

State and county reportable disease data. The state health department receives laboratory and clinician reports and investigates each case, classifying it as travel-associated or locally acquired. This is the most timely and locally useful source, but its counts depend on how often clinicians think to test for dengue in someone who has not traveled.

Mosquito surveillance. The county's mosquito control district places traps across neighborhoods and records the presence and number of Aedes aegypti. These data show where transmission is possible before any human case occurs, but they measure mosquitoes, not infections.

Genomic and published research. Sequencing studies such as the Florida analysis show how viruses are introduced and whether they spread locally, which helps target prevention. They are usually published months after the events they describe.

What the Local Data Show

Putting the sources together gives a clear local picture. Twelve of the 14 locally acquired cases lived within half a mile of a travel-associated case reported in the previous month, which fits the pattern of introduction followed by short chains of local spread. Aedes aegypti was found in about 70% of residential traps in the three neighborhoods where local cases clustered, compared with about 35% elsewhere in the county. Two of the local cases were first seen by clinicians who did not test for dengue at the first visit because the patients had not traveled, which delayed the investigation by more than a week. These findings point to three targets for education: residents in high-mosquito neighborhoods, travelers returning from areas with dengue and local clinicians.

Community Education Strategy

Research supports community action. In a cluster randomized trial in Nicaragua and Mexico, evidence-based community mobilization that engaged residents in removing mosquito breeding sites reduced the risk of dengue infection in children by 29.5%, reduced reports of dengue illness and reduced the share of houses with mosquito larvae or pupae, compared with routine government control alone (Andersson et al., 2015). The program was also inexpensive, costing about US$16.72 per person a year in Mexico and $7.47 in Nicaragua, using community health workers to support residents (Tschampl et al., 2020). The county's strategy is built on that approach, adapted to a U.S. setting.

Audience. Homeowners and renters in the neighborhoods where traps show the most Aedes aegypti and where local cases occurred, with specific outreach to families who travel frequently to areas with dengue.

Core action. Once a week, tip and toss: empty or cover anything that holds water around the home. This single, repeated action is the behavior residents control most directly.

Supporting actions. Use insect repellent during the day, repair window screens and see a clinician for fever within two weeks of travel or after mosquito bites, mentioning any travel.

Messengers and channels. Neighborhood associations, churches, schools and trained community volunteers lead block walks and yard checks; the mosquito control district shares trap results by neighborhood on a public map; messages go out in English, Spanish and Haitian Creole by text, radio and flyers. Clinicians receive a letter asking them to test patients with compatible symptoms even without travel.

Timing. The strategy runs from April through November, the county's peak mosquito season, with extra outreach within a block of any new case.

Evaluation

The county will track the share of trapped mosquitoes that are Aedes aegypti in target neighborhoods, the percentage of homes with breeding containers at volunteer yard checks, the number of dengue tests ordered by local clinicians and the number of locally acquired cases each year. Because local transmission depends on imported cases, the number of locally acquired cases will vary with travel patterns, so trap and yard-check data will be the main short-term measures of the strategy's effect.

References

Andersson, N., Nava-Aguilera, E., Arostegí, J., Morales-Perez, A., Suazo-Laguna, H., Legorreta-Soberanis, J., Hernandez-Alvarez, C., Fernandez-Salas, I., Paredes-Solís, S., Balmaseda, A., Cortés-Guzmán, A. J., Serrano de los Santos, R., Coloma, J., Ledogar, R. J., & Harris, E. (2015). Evidence based community mobilization for dengue prevention in Nicaragua and Mexico (Camino Verde, the Green Way): Cluster randomized controlled trial. BMJ, 351, h3267. https://doi.org/10.1136/bmj.h3267

Jones, F. K., Morrison, A. M., Santiago, G. A., Rysava, K., Zimler, R. A., Heberlein, L. A., Kopp, E., Saunders, K. E., Baudin, S., Rico, E., Mejía-Echeverri, Á., Taylor-Salmon, E., Hill, V., Breban, M. I., Vogels, C. B. F., Grubaugh, N. D., Paul, L. M., Michael, S. F., Johansson, M. A., . . . Stanek, D. R. (2024). Introduction and spread of dengue virus 3, Florida, USA, May 2022-April 2023. Emerging Infectious Diseases, 30(2), 376-379. https://doi.org/10.3201/eid3002.231615

Tschampl, C. A., Undurraga, E. A., Ledogar, R. J., Coloma, J., Legorreta-Soberanis, J., Paredes-Solís, S., Arostegí, J., Hernández-Álvarez, C., Harris, E., Andersson, N., & Shepard, D. S. (2020). Cost-effectiveness of community mobilization (Camino Verde) for dengue prevention in Nicaragua and Mexico: A cluster randomized controlled trial. International Journal of Infectious Diseases, 94, 59-67. https://doi.org/10.1016/j.ijid.2020.03.026