South Florida Parasite Spillover Initiative

A structured program for studying parasite movement among native and non-native reptiles and amphibians across the urban–wetland interface.

The question

Which host–parasite relationships are changing—and what do those changes mean?

South Florida combines protected wetlands, canals, roadway corridors, suburban habitats, wildlife trade, and an unusually diverse introduced herpetofauna. That landscape creates opportunities for parasite introduction, host switching, range expansion, and altered transmission.

SEPS distinguishes introduced-parasite spillover from native-parasite acquisition and reserves the term spillback for evidence that an introduced host actually increases transmission pressure on native hosts.1 2

Diagram distinguishing spillover, native parasite acquisition, potential spillback, and co-introduction — Conceptual framework used to keep ecological claims precise.

Priority questions

A regional program with defined evidence thresholds.

Host range

Which native and introduced hosts support immature, encysted, or mature parasite stages—and in which anatomical sites?

Transmission geography

How do host movement, habitat edges, season, and locality class relate to parasite occurrence and burden?

Competence and consequence

Does a novel host merely contain a parasite, support development, permit reproduction, or alter onward transmission?

Evidence sequence

Strong ecological language requires more than an unusual specimen.

Candidate associationDocumented host, parasite-like specimen, anatomical site, image, and preserved material.

Confirmed parasite recordExpert morphology and/or molecular evidence linked to a voucher.

Definitive-host evidenceAdults in the expected site, ideally repeated across hosts and supported by maturity or reproduction.

Shared transmission systemComparable parasite lineage documented across introduced and native hosts.

Spillback claimEvidence that the introduced host increases infection pressure or onward transmission to native hosts.

Sampling philosophy

Collect the missing evidence—not animals indiscriminately.

The initiative prioritizes animals already available through authorized management removals, road mortality, collaborator necropsies, archived material, and other approved sources. Every specimen should produce the maximum defensible record: host data, necropsy context, parasite inventory, vouchers, calibrated images, and molecular aliquots when appropriate.

Nonlethal sampling and opportunistic material are preferred when they can answer the question. Internal infection site, burden, and life stage often require necropsy, so the program emphasizes careful use of specimens already available through approved work.

Acquired light-microscopy view of parasite morphology

Real microscopy from the existing SEPS archive; no synthetic biological imagery is used on this site.

Long-term regional goals

Move from isolated records to an interpretable surveillance network.

Baseline

Establish host, locality, life-stage, and parasite-community baselines across priority corridors and habitat classes.

Signal detection

Identify new host associations, range extensions, unusual burdens, and repeatable morphology shifts without overstating them.

Response

Provide review-ready records that can support targeted re-sampling, molecular confirmation, museum deposition, and agency communication.