Dataset Information

Validation of the Use of Dried Blood Samples for the Detection of Toxoplasma gondii Antibodies in Stray Cats (Felis s. catus).

ABSTRACT: If validated beforehand, the analysis of dried blood on blotting paper (BP samples) is very useful for monitoring free-ranging animals. We aimed to validate this method for the detection of antibodies against Toxoplasma gondii in stray cats. We used the modified agglutination test (MAT) in 199 sample pairs of sera and BP samples from 54, 39, 56, and 50 cats trapped during four periods in five dairy farms. Screening was at 1:6, 1:12, and 1:24 dilutions. The cut-off value was at MAT titre ≥ 24, but MAT titre ≥ 12 was also considered for BP samples that often have a higher dilution level. Depending on the period, sample type, and cut-off value, sensitivity of the analysis of the BP sample vs. serum varied from 87.1% to 100% and specificity ranged from 72.22% to 100%. The concordance values and Kappa coefficient showed a substantial to excellent agreement between the results of the two methods, whatever the cut-off value. These findings quantifiably validate the use of MAT on BP samples for the detection of antibodies to T. gondii in stray cats, but we recommend expressing results from BP samples with several cut-off values as the MAT titres tend to be lower than those of sera.

SUBMITTER: Simon JA

PROVIDER: S-EPMC8308602 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature

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Validation of the Use of Dried Blood Samples for the Detection of Toxoplasma gondii Antibodies in Stray Cats (Felis s. catus).

Simon Julie Alice JA Aubert Dominique D Geers Régine R Villena Isabelle I Poulle Marie-Lazarine ML

Pathogens (Basel, Switzerland) 20210708 7

If validated beforehand, the analysis of dried blood on blotting paper (BP samples) is very useful for monitoring free-ranging animals. We aimed to validate this method for the detection of antibodies against Toxoplasma gondii in stray cats. We used the modified agglutination test (MAT) in 199 sample pairs of sera and BP samples from 54, 39, 56, and 50 cats trapped during four periods in five dairy farms. Screening was at 1:6, 1:12, and 1:24 dilutions. The cut-off value was at MAT titre ≥ ...[more]

PMID: 34358014

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Project description:BACKGROUND: Toxoplasma gondii is prevalent in most areas of the world and may cause abortions or neonatal complications in humans. As the only definitive host, cats play an important role in the epidemiology of the disease. Infection rates in cats, especially stray or free-living cats, are considered to be the best sentinels of the level of T. gondii in the environment. The T. gondii infection can be diagnosed in different ways with different methods depending on the target. However, little information on T. gondii infection in cats was available in Shanghai, China. Moreover reports on prevalence of circulating antigens, antibodies and DNA of T. gondii in the same study are rare. METHODS: In the present study, the presence of antibodies (Ab), circulating antigens (CA), and/or DNA of Toxoplasma gondii in samples from 145 stray or unwanted cats from 6 animal shelters in Shanghai (China) was determined in order to estimate the prevalence of T. gondii infection, by Ab-ELISA, CA-ELISA, and nested-PCR, respectively. RESULTS: The positive rates for the antibodies, circulating antigen and DNA of T. gondii were 11.7% (17 of 145), 5.5% (8 of 145) and 5.71% (2 of 35), respectively. No cat tested was positive by both the Ab-ELISA and the CA-ELISA, but the results of the PCR were consistent with the CA-ELISA assay. Therefore, the overall estimated prevalence of toxoplasmosis was 17.2% (25 of 145). According to our results, the positive rates of specific antibodies and circulating antigen of T. gondii were significantly different between adult cats (>1?year old) and juvenile cats (?1?year old); the former was 13.5% versus 3.9% by Ab-ELISA, while the latter was 1.7% versus 23.1% by CA-ELISA. From the results obtained with all three detection methods used in this study, the rate of infection was not significantly different between male and female cats (P ?0.05); and the overall rate was 17.9% for males versus 16.4% for females. CONCLUSIONS: The results suggest that detection of circulating antigens (CA) is necessary in surveys of T. gondii infection, especially for juvenile cats. Our investigation revealed that the prevalence of T. gondii infection in stray cats in Shanghai is high. Control programs are needed for stray cat populations in order to reduce the risk of zoonotic transmission of toxoplasmosis to other domestic animals and humans, especially females.

Project description:BackgroundToxoplasma gondii is a protozoan parasite which can infect almost all warm-blooded animals and humans. Understanding the differential expression of proteins and transcripts associated with T. gondii infection in its definitive host (cat) may improve our knowledge of how the parasite manipulates the molecular microenvironment of its definitive host. The aim of this study was to explore the global proteomic alterations in the major organs of cats during acute T. gondii infection.MethodsiTRAQ-based quantitative proteomic profiling was performed on six organs (brain, liver, lung, spleen, heart and small intestine) of cats on day 7 post-infection by cysts of T. gondii PRU strain (Genotype II). Mascot software was used to conduct the student's t-test. Proteins with P values < 0.05 and fold change > 1.2 or < 0.83 were considered as differentially expressed proteins (DEPs).ResultsA total of 32,657 proteins were identified in the six organs, including 2556 DEPs; of which 1325 were up-regulated and 1231 were down-regulated. The brain, liver, lung, spleen, heart and small intestine exhibited 125 DEPs, 463 DEPs, 255 DEPs, 283 DEPs, 855 DEPs and 575 DEPs, respectively. Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of all proteins and DEPs in all organs showed that many proteins were enriched in binding, cell part, cell growth and death, signal transduction, translation, sorting and degradation, extracellular matrix remodeling, tryptophan catabolism, and immune system. Correlations between differentially expressed proteins and transcripts were detected in the liver (n = 19), small intestine (n = 17), heart (n = 9), lung (n = 9) and spleen (n = 3).ConclusionsThe present study identified 2556 DEPs in six cat tissues on day 7 after infection by T. gondii PRU strain, and functional enrichment analyses showed that these DEPs were associated with various cellular and metabolic processes. These findings provide a solid base for further in-depth investigation of the complex proteotranscriptomic reprogramming that mediates the dynamic interplays between T. gondii and the different feline tissues.

Project description:Cats are obligate carnivores and under most circumstances eat only animal products. Owing to the pseudogenization of one of two subunits of the sweet receptor gene, they are indifferent to sweeteners, presumably having no need to detect plant-based sugars in their diet. Following this reasoning and a recent report of a positive correlation between the proportion of dietary plants and the number of Tas2r (bitter receptor) genes in vertebrate species, we tested the hypothesis that if bitter perception exists primarily to protect animals from poisonous plant compounds, the genome of the domestic cat (Felis catus) should have lost functional bitter receptors and they should also have reduced bitter receptor function. To test functionality of cat bitter receptors, we expressed cat Tas2R receptors in cell-based assays. We found that they have at least 7 functional receptors with distinct receptive ranges, showing many similarities, along with some differences, with human bitter receptors. To provide a comparative perspective, we compared the cat repertoire of intact receptors with those of a restricted number of members of the order Carnivora, with a range of dietary habits as reported in the literature. The numbers of functional bitter receptors in the terrestrial Carnivora we examined, including omnivorous and herbivorous species, were roughly comparable to that of cats thereby providing no strong support for the hypothesis that a strict meat diet influences bitter receptor number or function. Maintenance of bitter receptor function in terrestrial obligate carnivores may be due to the presence of bitter compounds in vertebrate and invertebrate prey, to the necessary role these receptors play in non-oral perception, or to other unknown factors. We also found that the two aquatic Carnivora species examined had fewer intact bitter receptors. Further comparative studies of factors driving numbers and functions of bitter taste receptors will aid in understanding the forces shaping their repertoire.

Dataset Information

Validation of the Use of Dried Blood Samples for the Detection of Toxoplasma gondii Antibodies in Stray Cats (Felis s. catus).

Publications

Validation of the Use of Dried Blood Samples for the Detection of <i>Toxoplasma gondii</i> Antibodies in Stray Cats (<i>Felis s. catus</i>).

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