Hidden Infections and Changing Environments.

Area of Science:

• Parasitology
• Ecology
• Environmental Science

Background:

• Cryptic parasite stages often lead to asymptomatic infections across diverse hosts.
• Disease dynamics are frequently linked to host condition, which is influenced by environmental changes.
• Symbionts can also shift from beneficial to detrimental roles under environmental stress.

Purpose of the Study:

• To investigate the factors enabling parasite persistence as asymptomatic infections in invertebrates.
• To explore the connection between environmental change and the progression to overt disease in invertebrate hosts.
• To highlight the understudied nature of invertebrate diseases and their ecological significance.

Main Methods:

• This is a review article, synthesizing existing research on asymptomatic invertebrate infections.
• Analysis of studies linking environmental change, host condition, and disease manifestation.
• Examination of data on parasite diversity and host-parasite interactions in invertebrates.

Main Results:

• Asymptomatic infections are common in invertebrates but significantly undersampled due to detection challenges and poorly characterized parasite groups.
• Environmental changes can precipitate the transition from asymptomatic to overt disease states.
• Altered disease dynamics in invertebrates can serve as indicators of ecosystem change.

Conclusions:

• Understanding asymptomatic invertebrate infections is crucial for appreciating context-dependent host-parasite interactions.
• Recognizing these infections can help identify novel disease outbreaks and provide complementary indicators of ecosystem health.
• Further research is needed to address the biased focus on practically important invertebrate diseases.