Influenza Virus

Commonly known as the flu, influenza is an infectious disease that spreads around the world in seasonal epidemics. As a global health threat, the flu causes substantial illness and death each year. Most cases of pneumonia, the number one killer of children in developing countries, begin with a viral infection like influenza. Information about seasonality and prevalence of influenza is crucial for effective prevention and control strategy, yet very limited data exists on the epidemiology of influenza in developing countries.

Child is tested at Health Center Socrates Flores Vivas in Managua, Nicaragua

Child is tested at Health Center Socrates Flores Vivas in Managua, Nicaragua

Launched in 2007, SSI’s Influenza Program currently runs three studies that provide invaluable information about the spread of influenza and other respiratory illnesses within Nicaragua, as well as key insights into clinical presentation and immune responses of children infected with the influenza virus.

1. PEDIATRIC COHORT STUDY

This study provides primary care to approximately 1,600 children ages 0-14 years at the Health Center Socrates Flores Vivas of the Nicaraguan Ministry of Health. Children who present to the health center with symptoms of influenza are tested using state of the art molecular methods (real-time PCR) for influenza infection and followed though the duration their illness.

As part of the program – supported by the Nicaraguan Ministry of Health and the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC) – nasal and throat swabs are collected from study participants who have flu-like symptoms. While the study has already revealed patterns of seasonality, multiple years’ worth of data will be needed for accurate information. In addition to influenza testing, analysis for other respiratory diseases has been set up at the Ministry of Health. This capacity proved critical during a dramatic outbreak of what turned out to be Respiratory Syncytial Virus (RSV) in August 2008, which killed many infants and the pandemic flu that affected the globe in 2009.

3. INFLUENZA BIRTH COHORT STUDY

Participants of this study are enrolled at birth and visited weekly by our team to collect symptom surveys and identify potential respiratory illnesses. Though logistically, this study can be incredibly challenging to maintain, it also provides SSI the opportunity to become even more connected to the community in Managua that we serve.

2. INFLUENZA HOUSEHOLD TRANSMISSION STUDY

In this study, SSI indexes cases of influenza and proceeds to monitor household members over a period of 30 to 45 days. The aim is to better understand the factors that impact household influenza transmission in a tropical setting such as Managua. Households are visited every other day to collect samples and clinical information, for an initial period of 10-12 days; and one more time after 4 weeks. Studying influenza at this level is key as up to 70% of transmission of influenza occurs in the household and it is a site where we can intervene to slow the spread of the disease.