Acta tropica最新文献

In recent years, globalization and climate change have led to a rise in the number of imported cases of Aedes-diseases in Europe, resulting in increased frequency and magnitude of local transmissions due to the presence of competent vectors. Recently, Italy has experienced the establishment of three exotic Aedes mosquitoes relevant to human health, Aedes albopictus, Aedes koreicus and Aedes japonicus. Aedes aegypti, the primary vector of dengue and yellow fever, distributed in tropical and subtropical regions, has recently reappeared in Europe and the risk for its re-introduction in Italy is high given the climatic conditions suitable for the species. To address the risk of introduction and spread of Aedes-diseases, the Health Authorities recommend the strengthening of entomological surveillance at regional level, particularly in strategic areas and Points of Entry, such as ports and airports. In 2021, a Korean research team developed a multiplex-PCR assay for the identification of six Aedini species, not including Ae. aegypti. In the present study, the previous diagnostic test was improved by designing reverse primers for the identification of Ae. aegypti and Aedes geniculatus. This latter native mosquito lays eggs morphologically similar to those of invasive species with which it can sometimes be found in sympatry. Furthermore, a ten-minute DNA extraction method was implemented. The results obtained demonstrate a perfect diagnostic capacity and sensitivity of the method in discriminating the five species tested. Here, findings of a sensitive, rapid and cost-effective molecular assay developed for the early identification of invasive species at high-risk sites are shown.

Pigs represent a reservoir of infectious diseases that can be transmitted to humans through feeding or close contact. The aim of this study was to evaluate the seroprevalence of three zoonotic pathogens (Brucella suis, Mycobacterium avium, and Paslahepevirus balayani, also called hepatitis E virus) in the swine population in the Campania region, Southern Italy. A total of 370 animals from 31 farms were sampled and tested with specific commercial ELISAs. Antibodies against hepatitis E virus were detected in 41.4% of the animals and in almost all the farms (83.8%). Mycobacterium avium and Brucella suis were less widespread (seroprevalences of 3.5% and 0% at the individual level, 32.3% and 0% at the farm level, respectively). The univariate analysis of risk factors showed that sex (males), location (Naples), age (growers and finishers), farm size, and system (intensive) were related to higher hepatitis E virus prevalences. We also found higher seroprevalences in pigs belonging to districts where bovines were the main ruminant species. This variable and age were confirmed as risk factors also in multivariate analysis. The data obtained highlighted how pigs are HEV reservoirs also in southern Italy and that pigs in this region are also exposed to Mycobacterium avium but not to Brucella suis.

Leishmaniasis causes 3,5M DALYs. Treatment often requires parenteral administration and causes debilitating side effects. Vaccines to prevent the most dramatic outcomes would be most welcome. The Proteophosphoglycan (PPG) is encoded by ppg1 to ppg4 and mediates interaction of Leishmania spp. with macrophages employing two motifs: leucine-rich (LRR), and alanine, proline, and serine repeats (APS). We PCR amplified, cloned, sequenced, and assessed the conservation of LRR and APS of ppg3 and ppg4 in L. braziliensis of 24 patients from Northeast Brazil, then compared them to Leishmania spp. from Genebank. Evolutionary divergencies (ED) between ppg alleles were calculated by Maximum Composite Likelihood. The amplification success of ppg3-lrr was 87.5%; ppg3-aps was 58.3%; and ppg4-lrr was 62.5%. ppg3-lrr presented two conserved alleles of equal frequencies, similar to reference strain's (ED = 0.000). ppg4-lrr presented three alleles with overall lower conservation (ED = 48.820). Conservation was high for two of the alleles (ED = 0.003) present in 87.5% of isolates. Three alleles of ppg3-aps were observed (overall ED = 0.730). One occurred in three L. braziliensis isolates being similar to reference strain's (ED = 0.009). The other two were present in 70% of the isolates, substantially deviating from the reference L. braziliensis (ED > 1.000). Phylogeny employing ppg3-lrr, ppg3-aps or ppg4-lrr clustered L. braziliensis reference and test isolates with the other subgenus Viannia species, segregating them from species of other New and Old-World subgenera. Overall, moderate polymorphism affected functional PPG motifs, opening the possibility of their consideration in eventual subunit vaccines against leishmaniasis.

With newer dengue outbreaks extending to regions that were previously unaffected, about half of the world's population is now at risk of dengue infection. This scale of dengue spread and its undistinguishing primary fever symptom demands embracing automated high-throughput diagnostic techniques for quicker confirmatory diagnosis which otherwise requires time, cost and skill intensive reverse transcription-polymerase chain reaction (RT-PCR). Magnetic bead-based automated chemiluminescence immunoassay (CLIA) is one potential platform that has proven its diagnostic potential for different diseases. However, adoption of CLIA for dengue diagnosis demands extensive validation for widespread implementation. To this end, we evaluated the diagnostic performance of CLIA in comparison with routine dengue diagnostic approaches such as rapid diagnostic test (RDT) and RT-PCR. RDT and CLIA detected the presence of dengue non-structural protein 1 (NS1) antigen while RT-PCR detected the presence of viral RNA. From the analysis of 204 samples, the dengue test positive percentage was 17.6%, 16.7% and 19.6% by RDT, CLIA and RT-PCR methods, respectively. CLIA exhibited a sensitivity of 77.5%, specificity of 98.17% and a Cohen's kappa agreement (κ) value of 0.802 with RT-PCR. In addition, CLIA also exhibited a high κ-value of 0.931 with RDT. These findings show the reliability of NS1 antigen detection using automated CLIA for dengue diagnosis. This supports the potential to adopt high-throughput automated CLIA for dengue diagnosis when resources and expertise required to meet the need for quick test result turnaround during outbreaks may be limited.

Mosquitoes constitute a monophyletic taxon with approximately 3,700 species, widely distributed across continents and recognized as primary vectors of various infectious agents. Despite their medical importance, limited information is available on the evolutionary biology and molecular taxonomy of many mosquito species. In this study, we report the complete mitochondrial genome sequences of Coquillettidia venezuelensis Theobald, 1912, Trichoprosopon digitatum Rondani, 1848, and Uranotaenia calosomata Dyar & Knab, 1907, collected from the Brazilian Amazon. Sequencing was performed using the NextSeq 500 platform, resulting in genomes averaging 15,329 bp in length, comprising 37 functional subunits (13 PCGs, 22 tRNA, and 2 rRNA) and an A+T-rich control region. Comparative analyses revealed conserved genome organization, codon usage bias favoring AT-rich codons, and evidence of purifying selection acting on PCGs. Notably, a unique tRNA gene rearrangement was identified in Tr. digitatum, supporting its association with the Sabethini tribe. Phylogenetic reconstruction using concatenated PCGs confirmed the monophyly of major mosquito lineages, corroborating current taxonomic classifications and previous molecular and morphological studies. Our findings enrich the genetic resources available for Culicidae, contributing to improved molecular taxonomy and evolutionary understanding of these taxa. Additionally, this study highlights the potential of using transcriptomic data to recover mitochondrial genomes, offering a valuable tool for future systematic and eco-epidemiological research. Integration of mitochondrial data with nuclear markers and expanded taxonomic sampling is recommended to enhance resolution of deeper phylogenetic relationships within Culicidae.