Objective:

Assess Trypanosoma cruzi infection and genetic diversity in common vampire bats in northern Belize, and explore possible overlap with parasite lineages found in insect vectors and human infections.

Approach:

• Sampling: Researchers tested 207 blood samples collected in 2019, 2021, and 2022 at two sites in northern Belize.
• Testing and analysis: Two PCR assays were used to detect T. cruzi. Researchers genotyped positive samples and performed next-generation sequencing on 10 selected samples, then assessed infection patterns and compared sequences with previously reported Belizean samples.

Key Findings:

• Overall, 86 of 207 bats (42%) tested positive for T. cruzi.
• Sequencing identified five discrete typing units (DTUs): TcI, TcIV, TcV, TcVI, and TcBat. TcBat and TcVI were documented in Belize for the first time.
• A TcIV haplotype from a bat clustered with sequences previously found in Belizean triatomine vectors and a 2020 human infection; this genetic overlap did not establish direct transmission.
• In adjusted analyses, infection odds were higher at Lamanai than at Ka’Kabish and higher in 2022 than in 2019. Age, sex, and reproductive status were not associated with infection probability.

Interpretation:

The authors suggested vampire bats may help maintain genetically diverse T. cruzi populations and could potentially connect wildlife, domestic, and human transmission cycles. The study did not establish specific transmission pathways or direct transmission to humans.

Limitations:

• Sampling covered only two sites and three field seasons, with unequal effort and incomplete seasonal coverage.
• Next-generation sequencing was limited to 10 positive samples, restricting characterization of parasite diversity and DTU frequencies.
• The study did not assess insect vector abundance, blood-meal sources, or bat immune function.
• Observed temporal differences require cautious interpretation.

Conclusion:

The authors called for integrated surveillance of bats, insect vectors, domestic animals, and humans to better characterize transmission networks and assess potential Chagas disease risks.

Sources:

• PLOS Neglected Tropical Diseases