About This Project

A novel herpesvirus likely indigenous to the magnificent frigatebird (Fregata magnificens) has been linked to episodes of mass mortality of chicks from the Grand Connétable Nature Reserve, a small island in French Guiana. In this colony, around 90% of chicks die each year after showing clinical signs of infection. We hypothesize that these episodes of mass juvenile mortality result from environmental pollutants altering the physiology and parental behaviour of adult frigatebirds.

Ask the Scientists

What is the context of this research?

The emergence of novel viruses is an issue of growing concern. However, new disease outbreaks can also flare up from common viruses. Exposure to sources of environmental stress (e.g., food shortage, pollutants) can decrease individual animals’ immunocompetence, facilitating viral activation and leading to clinical symptoms of viral diseases.

French Guiana is experiencing a dramatic increase in mercury contamination as a result of mining activities. This raises the important question of whether mercury is one of the factors promoting the development of disease in frigatebird chicks exposed to the herpesvirus. Chemical contaminants like mercury can interfere with the function of the hormone prolactin, that regulates parental care behavior in birds.

What is the significance of this project?

Mercury exposure is a global threat to humans and wildlife. To date, however, the relationship between mercury and disease outbreaks in wild animal populations has received very little attention.

This poorly covered research topic clearly deserves more investigation given the likely climate change-related increase in infectious disease occurrence, and projections suggesting that the amount of mercury in fish may double by 2050.

These factors represent a long-term threat to wildlife, making it increasingly critical to identify the potential connections between mercury and viral disease. This project will represent a fundamental contribution to our understanding of how environmental change can trigger infectious disease outbreaks in wild animal populations.

What are the goals of the project?

Our goal is to deploy GPS tags on adult males and females over several months to monitor their breeding and post-breeding behaviors in relation to their blood mercury levels.

We hypothesized that adult birds with a higher mercury load:

i) provide less parental care, and do not provide sufficient food for their chicks, and ii) abandon the chick earlier, making the chick more susceptible to the disease.

We will also be able to i) assess the impact of the virus on the mortality rate of adults and ii) to identify other populations having a strong exchange of individuals with French Guiana, which could increase the spread of the virus and ultimately put multiple populations at risk.