Biology subjects

Verocai, G. G.

Publications and source records attributed to Verocai, G. G..

5 recordsLinked to original sources

bioRxiv2025

An open source MALDI-TOF mass spectrometry database for the identification of North American tick species of medical and veterinary importance.

Matrix-assisted laser desorption/ionization coupled with time-of-flight mass spectrometry (MALDI-TOF MS) is a fast emerging and robust method for rapid and accurate characterization of arthropod vectors. Correct identification of ticks is key in monitoring medically or veterinary relevant species and associated pathogens. It has been extensively used for tick identification based on leg proteins; however, in North America, MALDI-TOF MS has not been explored for comprehensive identification of ticks, except for a few studies focusing on a limited number of species. Herein, we have generated proteomic spectral profiles of nine North American tick species belonging to five genera obtained from laboratory-maintained colonies. From the 407 high-quality MS spectra generated in this study, 44 were deposited in our newly made database and used as reference. All remaining MS spectra were used to query and validate the database. All specimens were identified correctly to the species level using MALDI-TOF MS, with reliable Log Score Values (LSVs) ranging from 1.72 to 2.86, and median and mean values of 2.41 and 2.40, respectively. A single exception noted: an Amblyomma mixtum was misidentified as Amblyomma tenellum. As a cost-effective, user-friendly, and high-throughput method, MALDI-TOF MS can serve as an alternative for accurately identifying tick species of veterinary and public health importance in North America, thereby supporting tick-borne disease surveillance efforts.

microbiology↗

bioRxiv2024

Population genomics reveals an ancient origin of heartworms in canids

Heartworms (Dirofilaria immitis) are parasitic nematodes that cause significant cardiopulmonary-associated morbidity and mortality in canids worldwide. The global spread of heartworms is believed to have occurred alongside the dispersal of domesticated dogs. To test this theory, we analysed the genomes of 127 specimens collected from mammalian carnivore hosts across four continents. Here we show distinct genetic differences between heartworms from different continents, indicating a more ancient dispersal in canid hosts than previously recognised. Using admixture analyses, we find an Asian origin for Australian heartworms, consistent with the arrival of dingoes thousands of years ago. Finally, the genetic relatedness between European and Central American heartworms suggests that modern dispersal, likely associated with human colonisation of the Americas by Europeans, occurred with domesticated dogs. This work sheds light on the population dynamics and deep evolutionary history of a globally widespread parasite of veterinary significance.

evolutionary biology↗

bioRxiv2024

Assessing the performance of TRX and DUF148 antigens for detection of prepatent Guinea worm (Dracunculus medinensis) infection in dogs

Guinea worm (GW, Dracunculus medinensis) is a nematode that causes a painful and debilitating neglected tropical disease in humans. The GW Eradication Program has decreased human infections by >99% over the last 40 years. However, GW emergence in animal hosts, particularly dogs, has hampered eradication efforts. Currently, there is no method for diagnosing GW infection in animals during the prepatent period, before the adult female worms emerge. Previous works have identified two GW proteins, TRX and DUF148, as immunoreactive antigens with GW-positive human and dog sera. This study developed and validated indirect enzyme-linked immunosorbent assays (ELISA) using each antigen alone or in a combination of both antigens. Using serum samples from experimentally exposed dogs, TRX and DUF148 showed reactivity at 9- and 11-weeks post-exposure, respectively. In an experimentally infected ferret, TRX and DUF148 showed reactivity at 13- and 15-weeks post-exposure, respectively. These antigens were further validated using sera of dogs from endemic villages in Chad (n=47) and shelter dogs from the non-endemic United States (n=492). DUF148 showed better reactivity and sensitivity of 76.6.% in detecting GW infection in prepatent sera compared to TRX. However, DUF148 cross-reacted with one serum sample from Brugia pahangi experimental infection and several shelter dog sera. The anti-DUF148 titer was significantly higher in the shelter dogs positive for gastrointestinal nematodes than in negative dogs. To mitigate this cross-reaction, we produced 3 peptides of DUF148. Peptide 3 from the C-terminal was more reactive with prepatent sera and had a sensitivity of 83%; however, the specificity was not superior to DUF148 whole antigen. The antibody response to DUF148 in Chad dogs with the history of GW emergence waned overtime but was detectable until two years post-GW-emergence. Our findings could facilitate the development of diagnostic methods for early detection of GW infection in dogs in endemic countries. Authors summaryDracunculiasis or Guinea worm (GW) disease is a neglected tropical disease caused by the nematode Dracunculus medinensis and is targeted for eradication by the World Health Organization. The main challenge for the eradication program is the emergence of animal infections, especially dogs. Diagnostic tests are needed to find infected dogs during the prepatent period to better control infection and prevent the spread of GW. Previous studies have found two immunoreactive GW proteins, TRX and DUF148. In this study, we validated these antigens to detect infection in before GW emergence. Using sera of dogs from endemic areas of Chad, we found that DUF148 was more reactive and had promising sensitivity to detect the prepatent infection in an indirect ELISA assay. However, DUF148 also showed cross-reaction with some sera of dogs from the Unites States, a non-endemic area for GW. To mitigate this cross-reactivity, we performed ELISA using shorter peptides. We found peptide 3 that covers the C-terminal of the protein is the immunogenic part of DUF148. However, peptide 3 ELISA did not outperform whole antigen ELISA. This study confirms the applicability of DUF148 ELISA in detecting prepatent infections in dogs and could assist the GW Eradication Program.

microbiology↗

bioRxiv2024

ves1α genes expression is the major determinant of Babesia bovis-infected erythrocytes cytoadhesion to endothelial cells

Babesia bovis causes the most pathogenic form of babesiosis in cattle, resulting in high mortality in naive adults. This parasite invades red blood cells (RBCs) within the bovine hosts where they multiply and produce clinical disease. Babesia bovis exports numerous proteins into invaded RBCs changing its properties. Thus, the infected RBCs (iRBCs) are capable to cytoadhere in the microvasculature of internal organs and brain, leading to respiratory distress, neurologic signs, and mortality. Variant Erythrocyte Surface Antigen 1 (VESA1) is one of those exported proteins by B. bovis which represents a major virulence factor due to its central role in immune evasion by antigenic variation and intravascular parasite sequestration. VESA1 is a heterodimer protein encoded by ves1 and ves1{beta} multigene family and localized on the ridges, the focal point for cytoadhesion. To gain further insights into the molecular mechanisms of cytoadhesion of B. bovis, we panned the parasites with bovine brain microvasculature endothelial cells, which resulted in obtaining several clones with different cytoadherence abilities. The transcriptome analysis of 2 high and 2 low cytoadherent clones revealed that ves1 sequences were diversified, likely resulting from genomic recombination. On the other hand, ves1{beta} sequences were almost identical among these 4 clones. Insertion and expression of ves1 of a clone with high binding into ef-1 locus of a low binging clone increased cytoadherence confirming the role of ves1 suggested by our transcriptome data. Whole genome sequencing of cytoadherent clones revealed active locus of ves1 on chromosome 2. These results suggest that VESA1a proteins encoded by ves1 genes determine the cytoadherence specificity and/or cytoadherence strength of B. bovis and they are in the active site for recombination. Author summaryBabesia bovis is an apicomplexan intraerythrocytic protozoan parasite which causes the most pathogenic form of babesiosis in cattle. This pathogenicity is the result of parasite multiplication and cytoadherence of infected red blood cells (iRBCs) in the microvasculature of brain and internal organs and is mediated by B. bovis surface exposed ligand, Variant Erythrocyte Surface Antigen 1 (VESA1). Here using parasite panning assay, transcriptomics, and genetic tools, we showed that VESA1a is the main determinant of B. bovis cytoadhesion. VESA1 are large hypervariable proteins (>100kDa) consisting of VESA1a and VESA1b subunits encoded by ves1 and ves1{beta} multigene family. Panning B. bovis with bovine brain endothelial cells resulted in obtaining cytoadherent parasite clones with different binding abilities. Comparative transcriptome analysis revealed diversification of ves1 sequences. Insertion and expression of ves1 of a clone with high-binding ability in the genome of a low-binding clone increased cytoadherence confirming the role of ves1. Mapping RNA-seq on the genome of cytoadherent clones revealed the locus of active transcription and this locus was suggested to be the active site for recombination which promoted the production of variants of ves1 with different binding abilities. Altogether, our results provide new insights into B. bovis cytoadhesion and VESA1 biology.

microbiology↗

bioRxiv2024

Evaluation of a novel Tc-24 recombinant antigen ELISA for serologic testing for Trypanosoma cruzi in dogs

Chagas disease is a parasitic infection caused by Trypanosoma cruzi. Diagnosis of chroni Chagas disease in dogs relies on limited serological test options. This study used a new Tc-24 recombinant antigen ELISA on an archival set of 70 dog serum samples from multi-dog kennel environments in Texas subjected to three existing Chagas serological tests. Tc-24 ELISA produced a quantitative result and could detect anti-T. cruzi antibodies in dogs with high sensitivity and specificity. Comparing individual tests to Tc-24 ELISA resulted in strong associations and correlations, which suggest that Tc-24 ELISA is a reliable and accurate diagnostic tool for dogs with a single test.

zoology↗