Prevalence and genetic characterization of feline leukemia virus in portuguese stray cats

Abstract Background With its large stray population, Portugal had the highest prevalence of the Feline Leukemia Virus (FeLV) infection in Europe. Progressive infection is still high, especially in southern Europe. In addition to the viral load, the subgroup is a determining factor in the development...

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Main Authors: Pedro Morais de Almeida, Adriana Belas, Mauro Bragança, Joana de Oliveira, Carlos Viegas
Format: Article
Language:English
Published: BMC 2025-03-01
Series:BMC Veterinary Research
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Online Access:https://doi.org/10.1186/s12917-025-04691-2
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author Pedro Morais de Almeida
Adriana Belas
Mauro Bragança
Joana de Oliveira
Carlos Viegas
author_facet Pedro Morais de Almeida
Adriana Belas
Mauro Bragança
Joana de Oliveira
Carlos Viegas
author_sort Pedro Morais de Almeida
collection DOAJ
description Abstract Background With its large stray population, Portugal had the highest prevalence of the Feline Leukemia Virus (FeLV) infection in Europe. Progressive infection is still high, especially in southern Europe. In addition to the viral load, the subgroup is a determining factor in the development of the various syndromes associated with this disease, which can be fatal, justifying the morbidity and mortality of this retrovirus. The aim of the study was to determine the prevalence of FeLV, the viral load and to identify the subgroup of circulating virus in stray cats in the Lisbon metropolitan area. This prospective study was conducted at the Veterinary Teaching Hospital of the FMV-ULusófona, from November 2022 to January 2023. Blood samples from 129 stray cats from the Lisbon metropolitan area were included. All samples were tested for p27 antigen detection and proviral DNA by qPCR. For the detection of FeLV subgroups (A, B and C) nested PCR was performed. Results The results showed that at the time of enrollment, 8.5% (n = 11/129) of the cats tested positive for FeLV using p27 antigen and qPCR for proviral DNA. Considering the proviral DNA load, 90.9% (n = 10/11) of the FeLV infections were classified as “likely progressive infection” (> 4.0 × 105 copies/mL). In the remaining animal, the FeLV infection was classified as “likely regressive infection” (≤ 4.0 × 105 copies/mL). In this study, the most common FeLV subgroup was a combination of AB (54,5%, n = 6/11), followed by FeLV-A (45,5%, n = 5/11). FeLV-C subgroup was not detected. Conclusions To the best of our knowledge, this is the first study to research FeLV subgroups in Portugal. The prevalence of FeLV in this group was consistent with our expectations. However, the molecular characterization differed significantly from that observed in other countries. These results suggest that stray cats may not be the main epidemiological concern.
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spelling doaj-art-a1ccc8518b0541c596bf1f5d008b60c52025-08-20T02:49:35ZengBMCBMC Veterinary Research1746-61482025-03-0121111210.1186/s12917-025-04691-2Prevalence and genetic characterization of feline leukemia virus in portuguese stray catsPedro Morais de Almeida0Adriana Belas1Mauro Bragança2Joana de Oliveira3Carlos Viegas4Faculty of Veterinary Medicine, Lusófona University- Lisbon University CentreFaculty of Veterinary Medicine, Lusófona University- Lisbon University CentreEgas Moniz School of Health and ScienceFaculty of Veterinary Medicine, Lusófona University- Lisbon University CentreAnimal and Veterinary Research Center (CECAV), University of Trás-os-Montes and Alto Douro (UTAD)Abstract Background With its large stray population, Portugal had the highest prevalence of the Feline Leukemia Virus (FeLV) infection in Europe. Progressive infection is still high, especially in southern Europe. In addition to the viral load, the subgroup is a determining factor in the development of the various syndromes associated with this disease, which can be fatal, justifying the morbidity and mortality of this retrovirus. The aim of the study was to determine the prevalence of FeLV, the viral load and to identify the subgroup of circulating virus in stray cats in the Lisbon metropolitan area. This prospective study was conducted at the Veterinary Teaching Hospital of the FMV-ULusófona, from November 2022 to January 2023. Blood samples from 129 stray cats from the Lisbon metropolitan area were included. All samples were tested for p27 antigen detection and proviral DNA by qPCR. For the detection of FeLV subgroups (A, B and C) nested PCR was performed. Results The results showed that at the time of enrollment, 8.5% (n = 11/129) of the cats tested positive for FeLV using p27 antigen and qPCR for proviral DNA. Considering the proviral DNA load, 90.9% (n = 10/11) of the FeLV infections were classified as “likely progressive infection” (> 4.0 × 105 copies/mL). In the remaining animal, the FeLV infection was classified as “likely regressive infection” (≤ 4.0 × 105 copies/mL). In this study, the most common FeLV subgroup was a combination of AB (54,5%, n = 6/11), followed by FeLV-A (45,5%, n = 5/11). FeLV-C subgroup was not detected. Conclusions To the best of our knowledge, this is the first study to research FeLV subgroups in Portugal. The prevalence of FeLV in this group was consistent with our expectations. However, the molecular characterization differed significantly from that observed in other countries. These results suggest that stray cats may not be the main epidemiological concern.https://doi.org/10.1186/s12917-025-04691-2Subgroup classificationFeLVViral loadsPhylogenetic diversitySouthern EuropeVirus reservoir
spellingShingle Pedro Morais de Almeida
Adriana Belas
Mauro Bragança
Joana de Oliveira
Carlos Viegas
Prevalence and genetic characterization of feline leukemia virus in portuguese stray cats
BMC Veterinary Research
Subgroup classification
FeLV
Viral loads
Phylogenetic diversity
Southern Europe
Virus reservoir
title Prevalence and genetic characterization of feline leukemia virus in portuguese stray cats
title_full Prevalence and genetic characterization of feline leukemia virus in portuguese stray cats
title_fullStr Prevalence and genetic characterization of feline leukemia virus in portuguese stray cats
title_full_unstemmed Prevalence and genetic characterization of feline leukemia virus in portuguese stray cats
title_short Prevalence and genetic characterization of feline leukemia virus in portuguese stray cats
title_sort prevalence and genetic characterization of feline leukemia virus in portuguese stray cats
topic Subgroup classification
FeLV
Viral loads
Phylogenetic diversity
Southern Europe
Virus reservoir
url https://doi.org/10.1186/s12917-025-04691-2
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