Some models for epidemics of vector-transmitted diseases.

Area of Science:

• Epidemiology
• Mathematical Biology
• Public Health

Background:

• Vector-transmitted diseases, including dengue, chikungunya, and Zika virus, pose significant global health threats.
• Zika virus, known since 1947, rapidly spread to South America in 2013, causing microcephaly and severe birth defects in infants born to infected mothers.
• Unlike dengue and chikungunya, Zika virus exhibits dual transmission routes: vector-borne and direct sexual contact.

Purpose of the Study:

• To formulate and analyze mathematical epidemic models for vector-borne diseases.
• To develop a model specifically for Zika virus, incorporating both vector and direct transmission.
• To estimate the basic reproduction number (R0) for these diseases using epidemic modeling.

Main Methods:

• Formulation and analysis of two distinct compartmental epidemic models.
• Derivation of expressions for the basic reproduction number (R0) for each model.
• Utilizing the initial exponential growth rate to estimate R0.
• Parameter fitting and R0 estimation using data from the 2015 Zika virus outbreak in Barranquilla, Colombia.

Main Results:

• Expressions for the basic reproduction number were derived for both models.
• The initial exponential growth rate can be used to estimate R0.
• The model incorporating direct transmission requires additional data to quantify the proportion of directly transmitted cases.
• Parameters were successfully fitted to the 2015 Zika outbreak data, yielding an estimated R0.

Conclusions:

• The developed models provide a framework for understanding and predicting the spread of vector-borne diseases.
• The study highlights the importance of considering dual transmission routes for diseases like Zika virus.
• Accurate estimation of the basic reproduction number is critical for effective public health interventions against these diseases.