{"title":"FcRγIIA attenuates pathology of cutaneous leishmaniasis and modulates ITAMa/i balance.","authors":"Ikram Hammi, Julien Giron-Michel, Myriam Riyad, Khadija Akarid, Damien Arnoult","doi":"10.1186/s13071-024-06593-y","DOIUrl":"10.1186/s13071-024-06593-y","url":null,"abstract":"<p><strong>Background: </strong>Leishmania is the causal parasite of leishmaniasis, a neglected tropical disease affecting millions of individuals worldwide, and its dissemination is linked to climate change. Despite the complexity and effectiveness of the immune response, the parasite has developed many strategies to evade it and take control of the host cell to replicate. These evasion strategies start at early stages of infection by hijacking immune receptors to mitigate the cellular response. In this study, we examined whether Leishmania uses the Fc receptor FcγRIIA/CD32a and its downstream signaling pathways to evade the host immune response.</p><p><strong>Methods: </strong>Regarding in vivo studies, CD32a transgenic mice and the corresponding wild types were infected with Leishmania major Friedlin strain. For the in vitro experiments, BMDMs isolated from WT or CD32a transgenic mice and control or CD32a knockdown differentiated THP-1s were infected with two species of Leishmania, Leishmania major and L. tropica.</p><p><strong>Results: </strong>In vivo, expression of FcγRIIA/CD32a was found to accelerate the signs of inflammation while simultaneously preventing the formation of necrotic lesions after Leishmania infection. In infected macrophages, the presence of FcγRIIA/CD32a did not affect the secretion of proinflammatory cytokines, while the balance between ITAMa and ITAMi proteins was disturbed with improved Fyn and Lyn activation. Unexpectedly, infection with L. tropica but not L. major triggered an intracytoplasmic processing of FcγRIIA/CD32a.</p><p><strong>Conclusions: </strong>Our observations underscore the significance of FcγRIIA/CD32a in cutaneous leishmaniasis and its potential use as a therapeutic target.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"517"},"PeriodicalIF":3.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11657761/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142854919","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}
Endashaw Esayas, Steven Gowelo, Muluken Assefa, Elodie A Vajda, Edward Thomsen, Asefaw Getachew, Temesgen Ashine, Getachew Mekonnen, Henry Ntuku, Adam Bennett, Lemu Golassa, Neil F Lobo, Endalamaw Gadisa
{"title":"Impact of nighttime human behavior on exposure to malaria vectors and effectiveness of using long-lasting insecticidal nets in the Ethiopian lowlands and highlands.","authors":"Endashaw Esayas, Steven Gowelo, Muluken Assefa, Elodie A Vajda, Edward Thomsen, Asefaw Getachew, Temesgen Ashine, Getachew Mekonnen, Henry Ntuku, Adam Bennett, Lemu Golassa, Neil F Lobo, Endalamaw Gadisa","doi":"10.1186/s13071-024-06607-9","DOIUrl":"10.1186/s13071-024-06607-9","url":null,"abstract":"<p><strong>Background: </strong>Ethiopia continues to grapple with a persistent malaria burden, characterized by ongoing transmission and recurrent outbreaks. Human behavior influences both malaria exposure and the effectiveness of vector interventions, complicating malaria control efforts. Implementing tailored strategies that account for the complex interplay between human activities and vector behavior remains a challenge in both high- and low-transmission areas in Ethiopia, particularly for vulnerable highland populations and temporary labor migrants, due to lack of data. The aim of this study was to examine the spatiotemporal patterns of human-mosquito interactions and evaluate the effectiveness and suitability of long-lasting insecticidal nets (LLINs) in settings involving lowland resident populations, seasonal migrant workers and highland communities.</p><p><strong>Methods: </strong>Concurrent human and vector behavior data were collected from high-transmission lowlands (residents and temporary migrant workers) and vulnerable highlands populations. Hourly human behavior observations (HBOs), which examined LLIN use, indoor versus outdoor human presence and sleeping patterns, were paired in a crossover design with mosquito sampling using US Centers for Disease Control light traps (CDC LT) as a proxy for mosquito biting behavior. The study was conducted during the peak (October-December 2022) and minor (March-May 2023) malaria transmission seasons ('peak' and 'minor') for a total of 368 nights. In the highlands, four villages consisting of eight households per village were selected for surveillance; in the lowlands, four villages consisting of two resident villages and two farm sites with migrant workers, with eight households/structures per village or farm, were used for data collection. CDC LT and HBO data were integrated to evaluate HBO-adjusted human biting rates (HBO-adjusted HBR) of Anopheles mosquitoes.</p><p><strong>Results: </strong>In the highland villages, residents predominantly engaged in indoor activities, with their peak activity overlapping with the peak biting hours (1800-2200 hours). A substantial proportion of inhabitants slept indoors without LLINs in the peak and minor seasons (42.8% and 39.2%, respectively). Highland residents were significantly more exposed to malaria vectors indoors (88.4% peak, 88.6% minor) than outdoors during both transmission seasons. In lowland villages, both resident and seasonal migrant worker populations exhibited predominantly outdoor activity, particularly during peak biting hours (1800-2300 hours). Both residents and temporary migrants were significantly more exposed to Anopheles mosquitoes outdoors (resident: 65.0% peak, 67.1% minor; migrant: 70.5% peak, 80.0% minor) than indoors during both transmission seasons. LLIN usage was minimal and offered limited protection, with < 16.63% of person-time spent under nets by resident populations and 10.7% by migrant workers.</p><p><strong>Conclusions","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"520"},"PeriodicalIF":3.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11658354/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142854943","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}
Amri S Abas, Alfred J Simfukwe, John P Masalu, Najat F Kahamba, Ismail H Nambunga, Dickson S Msaky, Alex J Limwagu, Abdallah R Kipekepeke, Carsten Wergin, Rukiyah M Njalambaha, Elison E Kemibala, Amour Seleman, Yeromin P Mlacha, Marceline Finda, Uli Beisel, Esther G Kimaro, Halfan S Ngowo, Fredros O Okumu
{"title":"Risk of Aedes-borne diseases in and around the Tanzanian seaport of Tanga despite community members being more concerned about malaria.","authors":"Amri S Abas, Alfred J Simfukwe, John P Masalu, Najat F Kahamba, Ismail H Nambunga, Dickson S Msaky, Alex J Limwagu, Abdallah R Kipekepeke, Carsten Wergin, Rukiyah M Njalambaha, Elison E Kemibala, Amour Seleman, Yeromin P Mlacha, Marceline Finda, Uli Beisel, Esther G Kimaro, Halfan S Ngowo, Fredros O Okumu","doi":"10.1186/s13071-024-06586-x","DOIUrl":"10.1186/s13071-024-06586-x","url":null,"abstract":"<p><strong>Background: </strong>Increased global trade, while beneficial economically, can also increase the spread of vector-borne diseases, particularly those transmitted by Aedes mosquitoes spreading via trade routes. Given the heightened trade-induced activity at ports of entry, it is particularly crucial to assess the risk of mosquito-borne diseases in these settings. This study compared the risks of Aedes-borne disease in and around the eastern Tanzanian seaport of Tanga.</p><p><strong>Methods: </strong>A 200 m × 200 m grid-based system was used to sample mosquitoes within the port area, and in surrounding areas at 2 km, 2.5 km, and 5 km away, between June and December 2023. We characterized mosquito breeding habitats, collected mosquito larvae using standard dippers and tested susceptibility of raised adult Aedes aegypti populations to different insecticides. Adult mosquitoes were collected using BG sentinel traps (daytime) and Centers for Disease Control (CDC) light traps (night-time). Additionally, more than 200 port users and neighboring residents were surveyed to assess their experiences with and perceptions of mosquito biting and disease risks.</p><p><strong>Results: </strong>There were 2931 breeding sites, with (60.8%, n = 1782) positive for Aedes larvae. The percentage of water-holding containers infested with Aedes immatures, i.e., the container index (CI), was highest in the port area (66.2%), and lowest 5 km away (44.6%). The port area also had a greater proportion of temporary breeding sites (64.9%) than did the surrounding areas. The adult mosquito surveys revealed 20,449 mosquito species including: Culex quinquefasciatus (56.2%), Mansonia uniformis (38.6%), Ae. aegypti (5.1%), Anopheles gambiae (0.1%), and Anopheles funestus. Ae. aegypti were more abundant in the port area than in the surrounding areas (P < 0.001), whereas Culex sp., and Mansonia sp., were significantly outside (P < 0.001). Adult Anopheles sp., were found only in the port area, but Anopheles larvae were found both within and outside the port areas. Tests on Ae. aegypti sp., revealed susceptibility to bendiocarb and DDT, and resistance to permethrin. Awareness of mosquito-borne diseases among respondents was high for malaria (64.8%), but low for dengue (26.3%) and Chikungunya (1.7%). Most respondents reported being bothered by mosquitoes mostly at night (53.4%) or in the evening (40.7%). In addition to insecticidal bednets, which are used primarily against malaria, preventive measures for Aedes-borne diseases are limited.</p><p><strong>Conclusions: </strong>This study identified significant potential risk of Aedes species, specifically Ae. aegypti sp., and associated diseases, but low perception of risk and inadequate personal protection measures in the study area. This low perception of risk highlights the need to improve public knowledge of the transmission and control of Aedes-borne diseases.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"512"},"PeriodicalIF":3.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11657424/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142855009","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}
Ingo Schäfer, Mathieu Faucher, Yaarit Nachum-Biala, Lluís Ferrer, Marina Carrasco, Alexandra Kehl, Elisabeth Müller, Torsten J Naucke, Gad Baneth
{"title":"Evidence for in vivo resistance against allopurinol in a dog infected with Leishmania infantum by reduction in copy numbers of the S-adenosylmethionine synthetase (METK) gene.","authors":"Ingo Schäfer, Mathieu Faucher, Yaarit Nachum-Biala, Lluís Ferrer, Marina Carrasco, Alexandra Kehl, Elisabeth Müller, Torsten J Naucke, Gad Baneth","doi":"10.1186/s13071-024-06583-0","DOIUrl":"10.1186/s13071-024-06583-0","url":null,"abstract":"<p><strong>Background: </strong>In Europe, canine leishmaniasis is commonly caused by Leishmania infantum. Allopurinol is the main drug for long-term management of the disease, and clinical relapses of L. infantum infection treated with this drug are described. Resistance to allopurinol has been demonstrated in-vitro, but there is only little knowledge on in vivo resistance in dogs.</p><p><strong>Findings: </strong>A two-year-old female spayed Akita Inu that was adopted from a breeding facility near Nice in France was initially diagnosed with primary immune-mediated hemolytic anemia. Immunosuppressive treatment was initiated, and the dog was referred for a second opinion to the Clinique Veterinaire Alliance in France. PCR testing for L. infantum was performed out of EDTA blood and IFA as well as ELISA testing out of serum. Resistance to allopurinol was associated with chromosome and gene copy number (CN) variations including a decrease in the S-adenosylmethionine synthetase (METK) gene CN.</p><p><strong>Results: </strong>The dog showed pale mucous membranes, fever (39.1 °C), and a relapse of the anemia. The diagnosis of leishmaniasis was based on the cytological finding of Leishmania amastigotes (bone marrow, spleen, liver), positive PCR testing, and positive IFAT serology. The dog was treated with allopurinol over a period of 1316 days and additionally received two cycles of Glucantime® (meglumine antimoniate), before samples were submitted to the LABOKLIN laboratory to test for resistance against allopurinol. The laboratory work-up revealed mild thrombocytopenia, mild hyperproteinemia with hyperglobulinemia, a marked elevation of the c-reactive protein, and decreased iron concentration. Serum protein electrophoresis showed a polyclonal peak in the gamma globulins. Serology was positive in both ELISA (21.5 LE) and IFAT (1:1024). Quantitative PCR testing of blood was positive with low numbers of Leishmania (10/ml blood) at the timepoint of suspicion for resistance. The urinary protein-to-creatinine ratio was markedly elevated (2.5) and xanthine crystalluria was detected. A CN level of below 3 is considered suspicious for resistance, as revealed in the described Akita Inu dog.</p><p><strong>Conclusions: </strong>Relapse of L. infantum infection after applying allopurinol for 1316 days due to resistance was suspected clinically. Positive PCR testing, consistent hematological and biochemistry abnormalities, and reduction in the METK gene CN backed up the clinical suspicion of resistance. Dogs infected with allopurinol resistant strains of L. infantum may represent a great risk for infection of naïve dogs, cats, and humans.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"506"},"PeriodicalIF":3.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11650845/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142838672","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}
Natalie Jakobs, Sandro Andreotti, Sabrina Ramünke, Georg von Samson-Himmelstjerna, Jürgen Krücken
{"title":"Differences in constitutive gene expression of cytochrome P450 enzymes and ATP-binding cassette transporter gene expression between a susceptible and a highly macrocyclic lactone-resistant Haemonchus contortus isolate in the absence of drug-inducible expression.","authors":"Natalie Jakobs, Sandro Andreotti, Sabrina Ramünke, Georg von Samson-Himmelstjerna, Jürgen Krücken","doi":"10.1186/s13071-024-06568-z","DOIUrl":"10.1186/s13071-024-06568-z","url":null,"abstract":"<p><strong>Background: </strong>Anthelmintic resistance in ruminants is a widespread problem that has a severe impact on productivity and animal welfare. The helminth Haemonchus contortus is generally considered the most important parasite in small ruminants due to its high pathogenicity and the widespread occurrence of anthelmintic resistance in it. Although the molecular mechanisms associated with resistance against the anthelmintics benzimidazoles (BZs) and levamisole are relatively well understood, the resistance mechanisms against the widely used anthelmintic macrocyclic lactones (MLs) ivermectin (IVM) and moxidectin (MOX) remain poorly understood. Detoxifying enzymes and xenobiotic transporters have been frequently proposed to play a role in ML resistance in multiple organisms, including nematodes.</p><p><strong>Methods: </strong>The reference genome of H. contortus was screened for cytochrome P450 genes (cyp genes) by using the Basic Local Alignment Search Tool, and maximum-likelihood phylogenetic analysis was used to assign the sequences to gene families. Fourth-stage larvae of the susceptible (McMaster) and the ML-resistant (Berlin-selected) H. contortus isolates were generated in vitro and compared regarding basal expression levels of cyp genes and ATP-binding cassette (ABC) transporters by using RNA sequencing. The resistant isolate was further incubated with 100 nM IVM or MOX for 3, 6 and 12 h, and the effects of incubation time and drugs were evaluated.</p><p><strong>Results: </strong>Twenty-five cyp genes were identified in the H. contortus genome and assigned to 13 different families. The ML-resistant isolate showed significantly higher and lower constitutive expression of 13 and four cyp genes, respectively. Out of the 50 ABC transporter genes, only six showed significantly higher expression in the ML-resistant isolate, while 12 showed lower expression. The fold changes were in general low (range 0.44-5.16). Only pgp-13 showed significant downregulation in response to IVM (0.77 fold change at 6 h, 0.96 fold change at 12 h) and MOX (0.84 fold change at 12 h). In contrast, mrp-5 was significantly, albeit minimally, upregulated in the presence of IVM, but not MOX, after 12 h (1.02 fold change).</p><p><strong>Conclusions: </strong>Despite little observable ML-inducible gene expression in the isolate examined here, some of the changes in the baseline expression levels might well contribute to ML resistance in the context of additional changes in a multigenic resistance model. However, neither cyp genes nor the ABC transporters appear to be the main drivers that can explain the high levels of resistance observed in the resistant isolate examined here.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"505"},"PeriodicalIF":3.0,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11636055/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142818811","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}
Ivo Petersen, Susanne Goebel-Lauth, Thierry Pobel, Maria J Gil, Wolfgang Löhlein, Oliver Wolf, Eva Zschiesche, Bjoern Welzel, Lea Heinau
{"title":"Clinical efficacy and safety of a single administration of fluralaner injectable suspension (BRAVECTO<sup>®</sup> injectable) vs. monthly administration of oral afoxolaner (NexGard<sup>®</sup>) in dogs for tick and flea control over one year under European field conditions.","authors":"Ivo Petersen, Susanne Goebel-Lauth, Thierry Pobel, Maria J Gil, Wolfgang Löhlein, Oliver Wolf, Eva Zschiesche, Bjoern Welzel, Lea Heinau","doi":"10.1186/s13071-024-06590-1","DOIUrl":"10.1186/s13071-024-06590-1","url":null,"abstract":"<p><strong>Background: </strong>Year-round control of canine flea and tick infestations requires owner compliance with recommendations for regular treatments. Compliance failures can result in increased exposure of dogs to tick-borne pathogens and resurgence of flea populations. This study investigated the year-long efficacy of fluralaner 150 mg/ml injectable suspension (BRAVECTO<sup>®</sup> injectable), developed to remove the need for multiple owner-administered, within-year treatments.</p><p><strong>Methods: </strong>This randomized, examiner-masked, non-inferiority study enrolled household dogs at veterinary clinics in Germany, France, and Spain. Each household contained a primary dog infested with ≥ 4 ticks or ≥ 5 fleas. Additional dogs in each household received the same treatment as the primary dog, either a single injection with fluralaner (15 mg/kg) on day 0, or 12 monthly treatments with oral afoxolaner (NexGard<sup>®</sup>) beginning on day 0. Owners presented their dogs for tick and flea assessments at visits 2 through 10 (days 14, 28, 56, 84, 112, 224, 280, 336, 365). Primary endpoints were the percentages of primary dogs free of live ticks or fleas at visit 10. Secondary endpoints were the percentage reductions of live ticks and fleas in primary dogs. All treated dogs were observed for adverse reactions throughout the study.</p><p><strong>Results: </strong>The analyzed per-protocol population included 415 primary dogs (fluralaner 279, afoxolaner 136) from 976 treated dogs (fluralaner 653, afoxolaner 323). From visits 2 through 10, ≥ 95% of primary dogs in each group were tick-free, and ≥ 93% were flea-free. The percentage of dogs free of ticks or fleas was non-inferior (P ≤ 0.0048) in the fluralaner group compared to the afoxolaner group at visit 10 and all earlier visits. Compared to baseline, fluralaner-group tick and flea counts were reduced by > 99%; afoxolaner-group tick and flea counts by > 98% and > 97%, respectively. There were no unexpected adverse events in any treated dog in either group, nor any sign of interactions between concomitantly administered vaccines and medications.</p><p><strong>Conclusions: </strong>A single subcutaneous fluralaner injection provided a level of tick and flea control equivalent to that of 12 monthly administrations of afoxolaner. The sustained fluralaner efficacy helps maintain canine health by retaining treatment with the veterinarian and eliminating treatment-compliance failures by pet owners between veterinary visits.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"504"},"PeriodicalIF":3.0,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11626764/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142801884","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}
Rahul Chaubey, Ashish Shukla, Anurag Kumar Kushwaha, Shakti Kumar Singh, Om Prakash Singh, Rajiv Kumar, Phillip Lawyer, Edgar Rowton, Christine A Petersen, Scott A Bernhardt, Shyam Sundar
{"title":"Monitoring alpha-cypermethrin susceptibility of Phlebotomus argentipes, the vector of visceral leishmaniasis in India, using the CDC bottle bioassay.","authors":"Rahul Chaubey, Ashish Shukla, Anurag Kumar Kushwaha, Shakti Kumar Singh, Om Prakash Singh, Rajiv Kumar, Phillip Lawyer, Edgar Rowton, Christine A Petersen, Scott A Bernhardt, Shyam Sundar","doi":"10.1186/s13071-024-06579-w","DOIUrl":"10.1186/s13071-024-06579-w","url":null,"abstract":"<p><strong>Background: </strong>Visceral leishmaniasis (VL), known as Kala-azar on the Indian subcontinent, is a parasitic disease caused by the flagellated protozoa Leishmania donovani and can be fatal if left untreated. The sand fly Phlebotomus argentipes is the only proven vector of VL in the Southeast Asia region, and VL control in this region has relied on the use of synthetic insecticides for indoor residual spraying (IRS). The use of DDT in VL control programmes has led to the development of resistance to this insecticide in sand flies, resulting in DDT being replaced with the insecticide alpha-cypermethrin. However, alpha-cypermethrin has a similar mode of action as DDT and, therefore, the risk of resistance development in sand flies increases under the pressure of regular exposure to this insecticide. In the present study we assessed the susceptibility status of wild-caught sand flies and F1 progeny using the CDC bottle bioassay.</p><p><strong>Methods: </strong>Sand flies were collected from 10 villages in Muzaffarpur District, Bihar, India. Eight of these villages are receiving continuous IRS with alpha-cypermethrin, one village had discontinued IRS with alpha-cypermethrin and one village had never received IRS with alpha-cypermethrin. The collected sand flies were exposed to a pre-determined diagnostic dose for a specific time duration (3 µg/ml for 40 min), and knockdown and mortality at 24 h post-exposure were recorded.</p><p><strong>Results: </strong>Knockdown ranged from 91.19% to 99.47% for wild-caught sand flies and from 91.70% to 98.89% for their F1 progeny. At 24 h post-exposure, mortality ranged from 89.34% to 98.93% for wild-caught sand flies and from 90.16% to 98.33% for F1 progeny.</p><p><strong>Conclusions: </strong>The results of this study showed that P. argentipes is potentially developing resistance, signalling the need for continuous monitoring and vigilance to sustain the validation of elimination once achieved.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"503"},"PeriodicalIF":3.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11622483/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142785308","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}
William Atherton, Luke Ambrose, James Wisdom, Bryan D Lessard, Nina Kurucz, Cameron E Webb, Nigel W Beebe
{"title":"Nuclear and mitochondrial population genetics of the Australasian arbovirus vector Culex annulirostris (Skuse) reveals strong geographic structure and cryptic species.","authors":"William Atherton, Luke Ambrose, James Wisdom, Bryan D Lessard, Nina Kurucz, Cameron E Webb, Nigel W Beebe","doi":"10.1186/s13071-024-06551-8","DOIUrl":"10.1186/s13071-024-06551-8","url":null,"abstract":"<p><strong>Background: </strong>The mosquito Culex annulirostris Skuse (Diptera: Culicidae) is an important arbovirus vector in Australasia. It is part of the Culex sitiens subgroup that also includes Cx. palpalis and Cx. sitiens. Single locus mitochondrial and nuclear DNA sequencing studies suggest that Cx. annulirostris consists of a complex of at least two species. We tested this hypothesis by analysing both nuclear microsatellite data and additional mitochondrial sequence data to describe the population genetics of Cx. annulirostris through Australia, Papua New Guinea (PNG) and the Solomon Archipelago.</p><p><strong>Methods: </strong>Twelve novel microsatellite markers for Cx. annulirostris were developed and used on over 500 individuals identified as Cx. annulirostris by molecular diagnostics. Ten of the 12 microsatellites then used for analysis using Discriminant Analysis of Principal Components, a Bayesian clustering software, STRUCTURE, along with estimates of Jost's D statistic that is similar to F<sub>ST</sub> but better suited to microsatellite data. Mitochondrial cytochrome oxidase I (COI) DNA sequence were also generated complementing previous work and analysed for sequence diversity (Haplotype diversity, Hd and Pi, π), Tadjima's D, and pairwise F<sub>ST</sub> between populations. An allele specific molecular diagnostic with an internal control was developed.</p><p><strong>Results: </strong>We confirm the existence of multiple genetically and geographically restricted populations. Within mainland Australia, our findings show that Cx. annulirostris consists of two genetically and geographically distinct populations. One population extends through northern Australia and into the south-east coast of Queensland and New South Wales (NSW). The second Australian population occurs through inland NSW, Victoria, South Australia, extending west to southern Western Australia. These two Australian populations show evidence of possible admixture in central Australia and far north Queensland. Australia's Great Dividing Range that runs down southeast Australia presents a strong gene-flow barrier between these two populations which may be driven by climate, elevation or river basins. In PNG we find evidence of reproductive isolation between sympatric cryptic species occurring through PNG and Australia's northern Cape York Peninsula. A PCR-based molecular diagnostic was developed to distinguish these two cryptic species.</p><p><strong>Conclusion: </strong>This study adds to the growing body of work suggesting that the taxon presently known as Cx. annulirostris now appears to consist of at least two cryptic species that co-occur in northern Australia and New Guinea and can be distinguished by a ITS1 PCR diagnostic. The Solomon Islands population may also represent a distinct species but in light its geographic isolation and lack of sympatry with other species would require further study. Additionally, the mitochondrial and nuclear DNA evidence of popul","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"501"},"PeriodicalIF":3.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11619117/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142780535","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}
Kimberly L Evasco, Craig Brockway, Tamara Falkingham, Margaret Hall, Nerida G Wilson, Abbey Potter
{"title":"First detection of Culex tritaeniorhynchus in Western Australia using molecular diagnostics and morphological identification.","authors":"Kimberly L Evasco, Craig Brockway, Tamara Falkingham, Margaret Hall, Nerida G Wilson, Abbey Potter","doi":"10.1186/s13071-024-06566-1","DOIUrl":"10.1186/s13071-024-06566-1","url":null,"abstract":"<p><strong>Background: </strong>Culex tritaeniorhynchus has long been considered the primary vector of Japanese encephalitis virus (JEV), but until recently, it was considered exotic to Australia. When the species was detected in the country's Northern Territory (NT) for the first time, the Western Australia (WA) Department of Health was cognisant of the risk it posed to the State because of the shared border and continuous mosquito habitat adjoining the two jurisdictions. The aim of this study was to undertake intensive mosquito surveillance in the Kimberley region to ascertain whether Cx. tritaeniorhynchus was present in WA, define the extent of its distribution and undertake phylogenetic analysis of select specimens to support hypothesized routes of entry into the state.</p><p><strong>Methods: </strong>Carbon dioxide (CO<sub>2</sub>)-baited encephalitis virus surveillance (EVS) mosquito traps were deployed at various sites throughout the Kimberley region by surveillance officers within the Medical Entomology unit of the Western Australia (WA) Department of Health. Mosquitoes were then morphologically identified, and a subset of four specimens were confirmed as Cx. tritaeniorhynchus by molecular identification using Cytochrome Oxidase I (COI) DNA data and phylogenetic analysis.</p><p><strong>Results: </strong>From 31 March 2021 to 30 May 2024, a total of 211 female Cx. tritaeniorhynchus specimens were collected from 21 unique trap sites in the Kimberley's Shire of Wyndham-East Kimberley (SWEK). Four COI DNA barcode regions were amplified and successfully sequenced for analysis. These sequences fell within a clade recognised as Cx. tritaeniorhynchus and specifically all sequences were in a clade with other specimens from the NT and Timor-Leste.</p><p><strong>Conclusions: </strong>This study represents the first detection of Cx. tritaeniorhynchus in WA. Given the widespread nature of trap sites that yielded the species and consecutive seasons over which it was observed, the authors surmise that Cx. tritaeniorhynchus is now established within the northeast Kimberley region. The findings are significant given the detection of the species coincides with the first significant outbreak of JEV activity on mainland Australia involving an estimated 45 human cases of Japanese encephalitis, 80 impacted commercial piggeries and widespread feral pig activity. Although the role that Cx. tritaeniorhynchus may play in JEV transmission into the future is not yet understood, it presents a potential risk to public health in the region.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"500"},"PeriodicalIF":3.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11616137/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142780518","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}
Renke Lühken, Leif Rauhöft, Björn Pluskota, Unchana Lange, Michelle Helms, Norbert Becker, Jonas Schmidt-Chanasit, Carola Kuhn, Egbert Tannich, Stephanie Jansen, Anna Heitmann
{"title":"High vector competence for chikungunya virus but heavily reduced locomotor activity of Aedes albopictus from Germany at low temperatures.","authors":"Renke Lühken, Leif Rauhöft, Björn Pluskota, Unchana Lange, Michelle Helms, Norbert Becker, Jonas Schmidt-Chanasit, Carola Kuhn, Egbert Tannich, Stephanie Jansen, Anna Heitmann","doi":"10.1186/s13071-024-06594-x","DOIUrl":"10.1186/s13071-024-06594-x","url":null,"abstract":"<p><strong>Background: </strong>The incidence of human infections caused by arthropod-borne viruses, such as the chikungunya virus (CHIKV), has increased globally due to a number of factors, such as climate change and globalization. The exotic mosquito species Aedes albopictus is a significant vector for CHIKV, raising concerns about its transmission potential in temperate regions, including Central Europe. We have therefore investigated the vector competence of Ae. albopictus for CHIKV at constant and fluctuating temperatures between 15 °C and 24 °C to assess the transmission risk in Europe.</p><p><strong>Methods: </strong>Aedes albopictus mosquitoes were reared and artificially infected with CHIKV. Infection rates and transmission efficiencies (TEs) were determined after 14 days of incubation at constant and fluctuating (± 5 °C) mean temperatures of 15 °C, 18 °C, 21 °C and 24 °C. In addition, mosquito locomotor activity was measured under the same fluctuating temperature conditions. A risk map for CHIKV transmission in Europe was generated combining temperature data and the current distribution of Ae. albopictus.</p><p><strong>Results: </strong>CHIKV transmission was observed at all tested temperatures. The highest TEs were recorded at fluctuating temperatures of 18 °C (54.3%) and 21 °C (58.6%), while the lowest TE was observed at a constant temperature of 15 °C (5.6%). TEs at fluctuating temperatures of 15 °C and 24 °C were the same (32.5%). Mosquito activity showed a nocturnal unimodal activity pattern with a peak during the start of the scotophase (hour 20). The proportion of active mosquitoes per hour increased with temperature and was nearly zero at 15 °C. The risk map indicated that regions in Southern and Central Europe, including recently invaded areas north of the Alps, have temperatures theoretically allowing CHIKV transmission for at least some days per year.</p><p><strong>Conclusions: </strong>While CHIKV can be transmitted by Ae. albopictus at 15 °C, the activity of this mosquito is strongly decreased at this temperature, likely reducing the transmission risk. These findings emphasize the importance of considering both vector competence and mosquito activity when assessing the risk of arbovirus transmission in temperate regions. Further studies are needed to validate these laboratory findings under field conditions.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"502"},"PeriodicalIF":3.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11619113/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142780533","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}