First molecular detection of Leishmania infantum in a domestic cat from Costa Rica
JFMS open reports · 2026
In plain language
This report describes the detection of Leishmania infantum in a lesion in one domestic cat from Costa Rica. Initial FeLV and FIV tests were negative, but testing was not repeated at the planned intervals. After the lesion was removed, the authors could neither confirm whether the infection had spread nor rule out infection remaining elsewhere in the body. The case did not evaluate drug efficacy or safety and cannot establish intervention effects in cats with FeLV.
Scientific detail
This clinical report, published in JFMS open reports in 2026, describes the first molecular detection of Leishmania infantum in a domestic cat from Costa Rica. It is a single case without a comparison group. Sequencing of the lesion PCR product showed 99.62% identity with the L infantum reference sequence MG778653. This finding supports molecular identification in the sampled lesion but does not establish systemic dissemination, parasite viability or any relationship to FeLV. The three claims in the knowledge object are classified as level C evidence.
Initial point-of-care tests for FeLV antigen and FIV antibodies were negative. Follow-up testing at the planned intervals was not performed, so these initial results do not definitively establish the absence of retroviral infection. The case does not represent an FeLV-infected study population.
The authors distinguish apparent local clinical control after lesion excision from exclusion of persistent infection: they could not rule out Leishmania persistence at other sites. Sampling limitations prevented confirmation of dissemination. Persistent infection was neither demonstrated nor ruled out. Clinical follow-up was owner-reported, and follow-up molecular testing was not reported.
Relevance to FeLV is contextual and indirect only. Retroviral coinfection is discussed as background, but FeLV pathogenesis, antiviral activity, drug repurposing and feline drug disposition were not evaluated. Nor were the efficacy, pharmacokinetics or safety of antiviral or anti-Leishmania drugs evaluated. The clinical course of this case cannot establish an intervention effect in FeLV-positive cats.
What we know
In one cat, the sequence of a lesion PCR product showed 99.62% identity with the L infantum reference MG778653, supporting molecular identification in that lesion. Initial FeLV antigen and FIV antibody tests were negative, but testing was not repeated. The authors could not exclude persistent infection at other sites. These claims are classified as level C evidence.
What we don't know
Systemic dissemination, parasite viability and the persistence or absence of infection at other sites were not established. Without follow-up retroviral testing, the absence of FeLV or FIV infection was not definitively established. Molecular follow-up was not reported. This case provides no evaluation of antiviral or anti-Leishmania drug efficacy, pharmacokinetics or safety and cannot establish intervention effects in FeLV-positive cats.
Evidence
EvidenceLevel C — Preliminary evidenceConfidence 100/100
The authors could not exclude persistence of Leishmania infection at sites other than the excised lesion.
Excerpt verified in the source — verbatim, in the source's own language“Moreover, the absence of lesion recurrence after surgical excision, despite the lack of anti- Leishmania treatment, suggests local clinical control; however, persistence of infection at other sites could not be excluded.”
The authors explicitly distinguish apparent local clinical control from exclusion of persistent infection; persistent infection was neither demonstrated nor ruled out.
EvidenceLevel C — Preliminary evidenceConfidence 100/100
The cat's initial point-of-care FeLV antigen and FIV antibody tests were negative, but scheduled-interval follow-up testing was not performed.
Excerpt verified in the source — verbatim, in the source's own language“Point-of-care testing for feline leukemia virus (FeLV) antigen and feline immunodeficiency virus (FIV) antibodies was performed using a commercial rapid immunochromatographic kit (FIVab/FeLV AG Test Kit; BioNote), and both results were negative. Follow-up testing in 30 days (FeLV) and 60 days (FIV) was not performed.”
This documents negative initial screening results in one cat, not definitively established absence of retroviral infection or findings from an FeLV-positive population.
EvidenceLevel C — Preliminary evidenceConfidence 100/100
Sequencing of the lesion PCR product showed 99.62% identity with the L infantum reference sequence MG778653.
Excerpt verified in the source — verbatim, in the source's own language“Sequencing of the PCR product showed 99.62% identity with L infantum (GenBank accession number MG778653 ), previously isolated from a naturally infected dog in Brazil.”
This supports molecular identification in the sampled feline lesion; it does not establish systemic dissemination, parasite viability or any relationship to FeLV.
Provenance
Source: First molecular detection of Leishmania infantum in a domestic cat from Costa Rica.
AVA