Parasites & Vectors最新文献

{"title":"End-point diagnostics of Giardia duodenalis assemblages A and B by combining RPA with CRISPR/Cas12a from human fecal samples.","authors":"Yilin Wang, Fuchang Yu, Yin Fu, Qian Zhang, Jinfeng Zhao, Ziyang Qin, Ke Shi, Yayun Wu, Junqiang Li, Xiaoying Li, Longxian Zhang","doi":"10.1186/s13071-024-06559-0","DOIUrl":"10.1186/s13071-024-06559-0","url":null,"abstract":"<p><strong>Background: </strong>Giardia duodenalis is a common enteric protozoan parasite that is categorized into eight assemblages (A-H). In particular, assemblages A and B are zoonotic, capable of infecting both humans and animals worldwide, resulting in significant economic losses and public health challenges in epidemic regions. Thus, the development of rapid, accurate and non-laboratory-based diagnostic methods for infected animals is crucial for the effective prevention and control of giardiasis. Recent advancements in clustered, regularly interspaced, short palindromic repeats (CRISPR) and CRISPR-associated (Cas) protein (Cas12a) systems allow promising avenues for nucleic acid detection, characterized by their high flexibility, sensitivity and specificity.</p><p><strong>Methods: </strong>Combined recombinase polymerase amplification and CRISPR/Cas12a systems were combined and used as end-point diagnostic methods (termed REPORT) to detect G. duodenalis assemblage A and B. The diagnostic results can be observed by fluorescence readouts with the naked eye under blue light or colorimetric signals using a lateral flow strip (LFS).</p><p><strong>Results: </strong>The limit of detection (LOD) of the REPORT‑based G. duodenalis assemblage A detection was 2.04 CFU/ml and 10 trophozoites per gram (TPG), and the LOD of assemblage B was 1.1 CFU/ml and 10 cysts per gram (CPG). The REPORT‑based G. duodenalis assemblage A and assemblage B detection methods have strong specificity and no cross-reactivity with other assemblages of G. duodenalis or common enteric parasitic protozoa and have excellent performance in clinical sample detection.</p><p><strong>Conclusions: </strong>This study presents a novel strategy for the direct identification of G. duodenalis assemblages A and B, requiring neither highly trained personnel nor costly specialized equipment.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"463"},"PeriodicalIF":3.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11558988/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142625740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relationship between malaria vector survival, infectivity, and insecticide-treated net use in western Kenya.","authors":"Lucy Abel, Emma Kimachas, Evans Omollo, Erick Nalianya, Tabitha Chepkwony, Joseph Kipkoech, Mark Amunga, Aggrey Wekesa, Jane Namae, Samuel Kahindi, Judith Mangeni, Zena Lapp, Christine F Markwalter, Steve M Taylor, Andrew Obala, Wendy Prudhomme O'Meara","doi":"10.1186/s13071-024-06550-9","DOIUrl":"10.1186/s13071-024-06550-9","url":null,"abstract":"<p><strong>Background: </strong>Significant effort and resources have been invested to control malaria transmission in sub-Saharan Africa, but it remains a major public health problem. For the parasite to be transmitted, the female Anopheles vector must survive 10-14 days following an infective bite to allow Plasmodium gametocytes to develop into infectious sporozoites. The goal of this study was to assess factors associated with wild-caught Anopheles survival and infection following host-seeking and indoor resting.</p><p><strong>Methods: </strong>The study was conducted between January 2020 to March 2022 in a longitudinal cohort of 75 households in 5 villages including a total of 755 household members in Bungoma County, Kenya. Monthly adult mosquito collection was conducted by attenuated aspiration in all enrolled households, and mosquitoes were reared for 7 days. The daily mortality rate was determined through day 7. All mosquitoes were morphologically identified. Female Anopheles were dissected, and species-level members of the Anopheles gambiae complex were resolved by molecular methods. The abdomens of all samples were processed for Plasmodium falciparum oocyst detection by PCR.</p><p><strong>Results: </strong>Within a 25-month period, the total numbers of non-Anopheles and Anopheles mosquitoes collected indoors were 12,843 and 712, respectively. Anopheles gambiae and An. funestus were the major vectors, though their distributions varied between different villages; 61.2% (n = 436/712) of the Anopheles mosquitoes survived up to day 7, with the lowest mortality rate recorded on day 5 of captivity. The survival rate also varied between the different Anopheles species. Six hundred eighty-three of 712 mosquito abdomens were tested for P. falciparum; 7.8% (53/683) tested positive for P. falciparum, with An. funestus having a higher (10%) prevalence than An. gambiae s.s. (6.0%, p = 0.095, Pearson Chi-square test). The proportion of household members sleeping under a bednet the night before mosquito collection varied across time and village. Anopheles funestus survival times were refractory to household ITN usage, and An. gambaie s.s. survival was reduced only under very high (100%) ITN usage.</p><p><strong>Conclusions: </strong>Despite ITN usage, mosquitoes still acquired blood meals and P. falciparum infections. Survival differed across species and was inversely correlated with high ITN usage in the household but not oocyst development.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"464"},"PeriodicalIF":3.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11558830/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142625656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation of Vetscan Imagyst^®, a diagnostic test utilizing an artificial intelligence deep learning algorithm, for detecting strongyles and Parascaris spp. in equine fecal samples.","authors":"Ashley Steuer, Jason Fritzler, SaraBeth Boggan, Ian Daniel, Bobby Cowles, Cory Penn, Richard Goldstein, Dan Lin","doi":"10.1186/s13071-024-06525-w","DOIUrl":"10.1186/s13071-024-06525-w","url":null,"abstract":"<p><strong>Background: </strong>Current methods for obtaining fecal egg counts in horses are often inaccurate and variable depending on the analyst's skill and experience. Automated digital scanning of fecal sample slides integrated with analysis by an artificial intelligence (AI) algorithm is a viable, emerging alternative that can mitigate operator variation compared to conventional methods in companion animal fecal parasite diagnostics. Vetscan Imagyst is a novel fecal parasite detection system that uploads the scanned image to the cloud where proprietary software analyzes captured images for diagnostic recognition by a deep learning, object detection AI algorithm. The study describes the use and validation of Vetscan Imagyst in equine parasitology.</p><p><strong>Methods: </strong>The primary objective of the study was to evaluate the performance of the Vetscan Imagyst system in terms of diagnostic sensitivity and specificity in testing equine fecal samples (n = 108) for ova from two parasites that commonly infect horses, strongyles and Parascaris spp., compared to reference assays performed by expert parasitologists using a Mini-FLOTAC technique. Two different fecal flotation solutions were used to prepare the sample slides, NaNO₃ and Sheather's sugar solution.</p><p><strong>Results: </strong>Diagnostic sensitivity of the Vetscan Imagyst algorithm for strongyles versus the manual reference test was 99.2% for samples prepared with NaNO₃ solution and 100.0% for samples prepared with Sheather's sugar solution. Sensitivity for Parascaris spp. was 88.9% and 99.9%, respectively, for samples prepared with NaNO₃ and Sheather's sugar solutions. Diagnostic specificity for strongyles was 91.4% and 99.9%, respectively, for samples prepared with NaNO₃ and Sheather's sugar solutions. Specificity for Parascaris spp. was 93.6% and 99.9%, respectively, for samples prepared with NaNO₃ and Sheather's sugar solutions. Lin's concordance correlation coefficients for VETSCAN IMAGYST eggs per gram counts versus those determined by the expert parasitologist were 0.924-0.978 for strongyles and 0.944-0.955 for Parascaris spp., depending on the flotation solution.</p><p><strong>Conclusions: </strong>Sensitivity and specificity results for detecting strongyles and Parascaris spp. in equine fecal samples showed that Vetscan Imagyst can consistently provide diagnostic accuracy equivalent to manual evaluations by skilled parasitologists. As an automated method driven by a deep learning AI algorithm, VETSCAN IMAGYST has the potential to avoid variations in analyst characteristics, thus providing more consistent results in a timely manner, in either clinical or laboratory settings.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"465"},"PeriodicalIF":3.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11558902/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142625657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mining the secreted and membrane transcriptome of Hyalomma dromedarii ticks for identification of potential protective antigens.","authors":"Nahla A Hussein, Asmaa S El-Shershaby, Shaimaa Abdel-Moez, Amr E El-Hakim, Yasser E Shahein","doi":"10.1186/s13071-024-06538-5","DOIUrl":"10.1186/s13071-024-06538-5","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Members belonging to the tick genus Hyalomma function as a multi-host reservoir for several pathogens and important parasites infesting large animals, such as camels, goats, cattle and sheep. In Egypt, there is a high risk of pathogen transmission as camels and cattle are imported from Sudan and Ethiopia and shipped to slaughterhouses and animal markets located in populated areas. Hyalomma dromedarii ticks are semi-desert vectors and, similar to other members of the genus Hyalomma, characterized by long-term feeding. During this process, different physiological, biochemical and immunological interactions occur within both the feeding ticks and their hosts. These biological changes affect the different tick developmental phases. The aim of this study was to explore the transcriptome of mixed messenger RNAs (mRNAs) collected from H. dromedarii eggs, larvae, nymphs and fed and unfed adults, using the Gateway cDNA library prepared in pCMV sport6.1 vector METHODS: The clones were sequenced and searched for potential secreted, membrane-associated or transmembrane (SMaT) sequences. The identified SMaT sequences were compared to the National Center for Biotechnology Information (NCBI) non-redundant protein sequence database using Blastx. Annotation and functional classification were achieved by comparison to sequences in the UniProtKB/Swiss-Prot and VectorBase databases and to the publicly available annotated proteomes of six hard tick species (H. asiaticum, Rhipicephalus sanguineus sensu lato, Dermacentor silvarum, Rhipicephalus microplus, Ixodes scapularis and Haemaphysalis longicornis) in addition to the published H. dromedarii sialotranscriptome. For the common sequences, we predicted the physicochemical properties, secondary structures and antigenicity of the fragments similar to matched sequences in the UniProtKB/Swiss-Prot database using three different methods.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;The quality-trimmed sequences from the cDNA library revealed 319 SMaT transcripts among 1248 sequenced clones. Annotation of the SMaT sequences using the UniProtKB/Swiss-Prot database revealed only 232 non-redundant sequences with at least one match. According to the UniProtKB/Swiss-Prot and Vectorbase databases, the SMaT sequences were either secreted (extracellular) (29 sequences) or cellular (transmembrane and membrane-associated) (203 sequences). These were classified into 10 functional classes: biogenesis (49 sequences), defense (9 sequences), development (36 sequences), signal transduction (28 sequences), transport (15 sequences), protein modification (33 sequences), homeostasis (6 sequences), metabolism (45 sequences) and miscellaneous/uncharacterized (11 sequences). A total of 60 sequences were shared between H. dromedarii SMaT, the sialotransciptome and six other hard tick species. The peptide fragments of these sequences that aligned to proteins from the UniProtKB/Swiss-Prot database were predicted to be promising ep","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"462"},"PeriodicalIF":3.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11555925/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142625653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distinct neutrophil effector functions in response to different isolates of Leishmania aethiopica.","authors":"E Adem, E Cruz Cervera, E Yizengaw, Y Takele, S Shorter, J A Cotton, G Getti, P Kropf","doi":"10.1186/s13071-024-06489-x","DOIUrl":"10.1186/s13071-024-06489-x","url":null,"abstract":"<p><strong>Background: </strong>In Ethiopia, cutaneous leishmaniasis is mainly caused by Leishmania (L.) aethiopica parasites and presents in three main clinical forms. It is still not clear if the host immune response plays a role in the development of these different presentations. Since neutrophils are likely to be one of the first immune cells present at the site of the sand fly bite, we set up an in vitro model of infection of neutrophils with L. aethiopica and assessed some of the main neutrophil effector functions: association with and internalisation of parasites, apoptosis and ROS production. We used three freshly isolated clinical isolates and one isolate that has been kept in culture for decades.</p><p><strong>Results: </strong>Our results showed by flow cytometry that all four L. aethiopica isolates had the ability to associate with neutrophils. The three clinical isolates of L. aethiopica associated more efficiently with neutrophils than the long-term cultured L. aethiopica. At 18 h, two distinct populations of neutrophils were identified that associated with L. aethiopica, CD15^high and CD15^low neutrophils. Confocal microscopy demonstrated that all isolates can be internalised. Our results also showed that all parasites induced apoptosis in L. aethiopica-associated neutrophils. Moreover, our results showed that after 2 h, L. aethiopica-associated neutrophils upregulated their production of ROS, but to a greater extent with the long-term cultured L. aethiopica. After 18 h of incubation, CD15^lowparasite⁺ showed an impaired ability to produce ROS compared to CD15^highparasite⁺.</p><p><strong>Conclusions: </strong>Using this in vitro model, our results show that different L. aethiopica parasite isolates, most notably long-term cultured parasites, had differential effects on neutrophil effector functions.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"461"},"PeriodicalIF":3.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11555981/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142625739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative performance analysis of different microfilaria testing methods for Dirofilaria immitis in canine blood.","authors":"Rachel C Smith, Trey D Tomlinson, Joy V Bowles, Lindsay A Starkey","doi":"10.1186/s13071-024-06537-6","DOIUrl":"10.1186/s13071-024-06537-6","url":null,"abstract":"<p><strong>Background: </strong>Microfilaria (MF) testing is an essential part of canine heartworm diagnostics, and it is recommended by the American Heartworm Society that a MF test be performed in tandem with antigen testing on every dog, every year, regardless of prevention status or history. There are a variety of methods that can be used to detect MF in canine whole blood; however, these methods widely vary in their sensitivities as well as practical factors, including time investment and cost. Additionally, some MF tests offer the advantage of being quantitative or allowing for morphological or molecular species identification, while other tests should only be used qualitatively.</p><p><strong>Methods: </strong>The purpose of this study is to evaluate the quantitative and qualitative performance of MF tests, including the 20 μL count, wet mount, 9 μL and 40 μL hematocrit tubes, thin smear, thick smear, modified Knott test (MKT), and conventional polymerase chain reaction (PCR).</p><p><strong>Results: </strong>Qualitatively, there was little difference in the performance of the 20 μL count, wet mount, MKT, and PCR. The MKT and PCR are the optimal MF tests, as these perform most reliably for detecting positives even when the MF per milliliter is relatively low, and in most cases, these two methods also allow for species-level confirmation of the identity. However, PCR tends to be a very costly test, and both PCR and MKT require a greater degree of expertise and time investment to perform than other tests. Even the lowest performance tests, including the thin smear and hematocrit tube methods, can reliably detect MF at very high burdens; although, caution should be advised when using low reliability methods, since there is a greater likelihood of failing to identify MF-positive dogs.</p><p><strong>Conclusions: </strong>Microfilaria (MF) testing is an essential part of heartworm diagnosis and screening in dogs, and test selection should balance practical factors such as cost and time investment with the patient's risk of infection based on prevention status and history, clinical signs, and antigen testing results. This approach to MF testing will help minimize cost while avoiding failure to detect MF in infected dogs, especially when MF burden is low.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"460"},"PeriodicalIF":3.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11555853/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142625737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in lipid abundance are associated with disease progression and treatment response in chronic Trypanosoma cruzi infection.","authors":"Juan Carlos Gabaldón-Figueira, Albert Ros-Lucas, Nieves Martínez-Peinado, Gavin Blackburn, Irene Losada-Galvan, Elizabeth Posada, Cristina Ballart, Elisa Escabia, Jordi Capellades, Oscar Yanes, María-Jesús Pinazo, Joaquim Gascón, Julio Alonso-Padilla","doi":"10.1186/s13071-024-06548-3","DOIUrl":"10.1186/s13071-024-06548-3","url":null,"abstract":"<p><strong>Background: </strong>Chagas disease, caused by the parasite Trypanosoma cruzi, is a zoonosis that affects more than seven million people. Current limitations on the diagnosis of the disease hinder the prognosis of patients and the evaluation of treatment efficacy, slowing the development of new therapeutic options. The infection is known to disrupt several host metabolic pathways, providing an opportunity for the identification of biomarkers.</p><p><strong>Methods: </strong>The metabolomic and lipidomic profiles of a cohort of symptomatic and asymptomatic patients with T. cruzi infection and a group of uninfected controls were analysed using liquid chromatography/mass spectrometry. Differences among all groups and changes before and after receiving anti-parasitic treatment across those with T. cruzi infection were explored.</p><p><strong>Results: </strong>Three lipids were found to differentiate between symptomatic and asymptomatic participants: 10-hydroxydecanoic acid and phosphatidylethanolamines PE(18:0/20:4) and PE(18:1/20:4). Additionally, sphinganine, 4-hydroxysphinganine, hexadecasphinganine, and other sphingolipids showed post-treatment abundance similar to that in non-infected controls.</p><p><strong>Conclusions: </strong>These molecules hold promise as potentially useful biomarkers for monitoring disease progression and treatment response in patients with chronic T. cruzi infection.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"459"},"PeriodicalIF":3.0,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11549750/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142636090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monitoring of pyrethroid resistance in Aedes aegypti: first report of double and triple kdr mutations in Buenos Aires Province.","authors":"Alberto N Barrera-Illanes, Lorena Ledesma, Agustin Alvarez-Costa, Agustín Balsalobre, Corina Juliana Toloza, Agustín Hernandez-Maiztegui, Andrea Jait, Ivana Sierra, María Victoria Micieli, Mariana Manteca-Acosta, Sheila Ons","doi":"10.1186/s13071-024-06547-4","DOIUrl":"10.1186/s13071-024-06547-4","url":null,"abstract":"<p><strong>Background: </strong>Dengue is an emerging disease in Argentina due to the colonization of Aedes aegypti, the mosquito vector. Buenos Aires Province is the biggest and most populated district in Argentina, suffering dengue outbreaks of growing magnitude. During epidemic periods, pyrethroid insecticides are used in this country to control adult mosquitoes. Pyrethroid resistance in dengue vectors has been reported worldwide, making it necessary to implement resistance management strategies. The voltage-gated sodium channel is the target site of pyrethroids. Mutations in the gene encoding this protein, called kdr mutations, are usually the molecular cause of pyrethroid resistance in insects. In Ae. aegypti from the Americas, three kdr substitutions were described: V410L, V1016I, and F1534C. The diagnostic of kdr mutations is recommended for the early detection of pyrethroid resistance as well as the consequent planning of evidence-based control policies.</p><p><strong>Methods: </strong>We distributed ovitraps across 16 localities in Buenos Aires Province, collecting 22,123 eggs. A total of 522 mosquitoes were genotyped in positions 1016 and 1534 of voltage-gated channel using multiplex high-resolution melting and/or TaqMan probe methods. A subset of 449 samples was also genotyped by a singleplex high-resolution melting method developed ad hoc and/or Sanger sequencing.</p><p><strong>Results: </strong>We have documented, for the first time to our knowledge in the central region of Argentina, the presence of the 1016Ikdr + 1534Ckdr allele. Additionally, our study reports the first identification of the V410L mutation in central Argentina. These results underscore a growing trend of pyrethroid resistance in Ae. aegypti, fueled by the widespread use of these insecticides.</p><p><strong>Conclusions: </strong>We detected 1016Ikdr + 1534Ckdr and 410Lkdr mutations in central Argentina for the first time and improved the processivity and accuracy of kdr genotyping methods. The results are both a tool for resistance monitoring and a sign of alarm to direct efforts towards finding sustainable methods for vector control to complement or replace pyrethroids. Joint efforts between academia and authorities to develop and implement public policies for vector control are a productive way to transfer scientific results for their application in public health.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"458"},"PeriodicalIF":3.0,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11549831/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142625654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variability of Loa loa microfilarial counts in successive blood smears and its potential implication in drug-related serious adverse events.","authors":"Tristan M Lepage, Jérémy T Campillo, Frédéric Louya, Paul Bikita, François Missamou, Marlhand C Hemilembolo, Sébastien D S Pion, Michel Boussinesq, Cédric B Chesnais","doi":"10.1186/s13071-024-06494-0","DOIUrl":"10.1186/s13071-024-06494-0","url":null,"abstract":"<p><strong>Background: </strong>The standard method to diagnose Loa loa infection and quantify microfilarial density (MFD) is the microscopic examination of calibrated thick blood smears (TBSs). In 1950, it was noticed that successive L. loa MFD samples from a single capillary puncture could exhibit up to 20% variation. Although loiasis treatment allocation is based on MFD to prevent serious adverse events (SAEs), data on this variability are scarce. There are also no guidelines supporting the collection and analysis of one or two TBSs.</p><p><strong>Methods: </strong>We assessed the variability of two successive L. loa MFD samples (MFD₁ and MFD₂), collected from 255 patients. We analyzed the influence of sex, age, weight, heart rate, arterial pressure, body temperature, and sampling time on MFD variability, as well the impact of MFD variability on MFD thresholds relevant to loiasis treatment protocols.</p><p><strong>Results: </strong>The MFD₂ was found to have increased in 63% (1145/1826) of TBS pairs and to have decreased in 37% (681/1826) of TBS pairs. The MFD₂ were on average 28% higher than the MFD₁. These variations drove a total of 333 (17.4%) changes in MFD classes according to loiasis treatment protocol, including 210 (11.3%) class increases. TBSs generated from blood samples from subjects with lower MFD (1-1000 mf/ml) or lower mean arterial pressure (MAP; 55-80 mmHg), or from blood samples collected at an earlier hour time-point (10:00-10:59 a.m.) were more subject to MFD₂ variability in a multivariate analysis. The MFD relative change was not constant over time for a given person.</p><p><strong>Conclusions: </strong>We observed a trend towards an increase in MFD₂ with an important variability between samples that may impact loiasis treatment allocation. We suggest that systematically sampling at least two successive TBSs might allow better MFD assessments to prevent post-treatment SAEs. Further studies are needed to verify this variability in larger samples as well as confirm the potential explanatory variables identified.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"457"},"PeriodicalIF":3.0,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11549846/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142623539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carry-over effects of Bacillus thuringiensis on tolerant Aedes albopictus mosquitoes.","authors":"Romina Bahrami, Stefano Quaranta, Hugo D Perdomo, Mariangela Bonizzoni, Ayda Khorramnejad","doi":"10.1186/s13071-024-06556-3","DOIUrl":"10.1186/s13071-024-06556-3","url":null,"abstract":"<p><strong>Background: </strong>The biological larvicide Bacillus thuringiensis subsp. israelensis (Bti) represents a safe and effective alternative to chemical insecticides for mosquito control. Efficient control of mosquitoes implicates continuous and extensive application of Bti. This massive use of Bti imposes strong selective pressure, but the complex mode of action of the numerous synergistic Bti endotoxins lower the risk of the emergence of resistance. Although resistance to Bti has not been identified at the population level in nature, some larvae can survive Bti exposure, suggesting tolerance mechanisms. Here we investigated whether Bti-tolerant Aedes albopictus larvae experience any fitness costs. We also studied how this tolerance affects different aspects of the phenotype of the emerging adults that could be relevant for arboviral transmission.</p><p><strong>Methods: </strong>We exposed Ae. albopictus larvae to lethal concentration of Bti and studied the fitness and gut microbiota of tolerant larvae and their adult counterparts. We further compared the transcript abundance of nine key immunity genes in the gut of Bti-tolerant larvae and their emerging adults versus those not exposed to Bti.</p><p><strong>Results: </strong>Our results showed that Bti exposure has multifaceted impacts on Ae. albopictus mosquitoes during both larval and adult stages. The carry-over effect of Bti exposure on tolerant larvae manifested in reduced adult emergence rate, shorter lifespan, and decreased fecundity. Bti also alters the gut microbiota of both larvae and adults. We observed higher microbial diversity in Bti-tolerant larvae and changes in the richness of core microbiota. Bti infection and the altered microbiota triggered immune responses in the larval and adult guts.</p><p><strong>Conclusions: </strong>The observed reduction in mosquito fitness and changes in the composition of the microbiota of adults emerging from tolerant larvae could negatively influence mosquito vectorial capacity. Understanding these impacts is crucial for evaluating the broader implications of Bti-based insecticides in mosquito control programs.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"456"},"PeriodicalIF":3.0,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11545555/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142605989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}