Acta tropica最新文献

{"title":"Effectiveness of a timed praziquantel treatment of school children in relation to seasonal transmission of urogenital schistosomiasis in Northwestern Tanzania","authors":"Nyanda C. Justine ,&nbsp;Humphrey D. Mazigo ,&nbsp;Antje Fuss ,&nbsp;Bonnie L. Webster ,&nbsp;Eveline T. Konje ,&nbsp;Titus R. Leeyio ,&nbsp;Klaus Brehm ,&nbsp;Andreas Mueller","doi":"10.1016/j.actatropica.2025.107530","DOIUrl":"10.1016/j.actatropica.2025.107530","url":null,"abstract":"<div><h3>Background</h3><div>Regular mass drug administration of praziquantel has a positive impact on reducing the burden of human schistosomiasis, however transmission still persists in many areas. To reach disease elimination; tailored interventions are needed to not only further reduce infections but also to tackle areas of persistent high prevalences of infection. One proposed approach is timed treatment based on the natural disease transmission cycle in relation to seasons. This study assessed the effectiveness of timed praziquantel treatment in a seasonal transmission foci of <em>S. haematobium</em> in northwestern Tanzania.</div></div><div><h3>Methods</h3><div>A longitudinal study was conducted among school aged children (SAC) between November 2022 and May 2023 in the Simiyu region, Tanzania. A single urine sample was collected from each of the participant and examined for <em>S. haematobium</em> eggs by the urine filtration method. Infected children were divided into two cohorts and treated with one dose of praziquantel, 40mg/kg of body weight in two different seasons. The first cohort was treated during the low transmission season, following the conclusion of the dry season in November 2022. In contrast, cohort two was treated during the high-transmission season, after the rainy season ended in May 2023. Cure rates and egg reduction rates were recorded at three-weeks post-praziquantel treatment for both cohorts.</div></div><div><h3>Results</h3><div>Out of 5265 screened participants, 517 and 274 <em>S. haematobium</em> infected SAC from the first and second cohorts respectively, participated in the study. The mean age for both cohorts was 11.2 ± 1.8 years. The prevalence of <em>S. haematobium</em> infection decreased by 12.0 %, from 17.7 % (95 %CI:16.4–19.1) to 5.7 % (95 %CI: 4.9–6.5) in cohort one, and by 11.4 %, from 15.5 % (95 %CI:13.9–17.1) to 4.1 % (95 %CI:3.2–5.0) in cohort two. The mean intensity of infection also decreased by 37.4 eggs/10 ml, from 41.2 to 3.8 eggs/10 ml of urine in cohort one (<em>p</em> &lt; 0.001), and by 4.1 eggs/10 ml, from 10.3 to 6.2 eggs/10 ml of urine in cohort two (<em>p</em> &lt; 0.001). The egg reduction rate was higher in cohort one (91 %) than in cohort two (40 %). Finally, there was a non-significant difference in cure rates between cohort one (64.2 %) and cohort two (69.7 %), (χ²(1) = 2.4107, <em>p</em> = 0.121).</div></div><div><h3>Conclusion</h3><div>Timed treatment with Praziquantel was effective in both cohorts, in terms of reduction in prevalence, heavy intensities, cure rate and egg reduction rates. However, it was less effective in the second cohort, which was treated during the high transmission season. In areas with seasonal transmission of <em>Schistosoma haematobium</em>, praziquantel should be administered during the low-transmission season to enhance its efficacy and increase the effectiveness of preventive chemotherapy programmes.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"262 ","pages":"Article 107530"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143045441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wing geometric morphometrics is effective to separate sand fly species (Diptera, Psychodidae, Phlebotominae) related with leishmaniasis transmission in Mexico","authors":"Yokomi N. Lozano-Sardaneta ,&nbsp;Oscar F. Mikery-Pacheco ,&nbsp;Herón Huerta ,&nbsp;Jorge Eduardo Rojas-Soriano ,&nbsp;Atilano Contreras-Ramos","doi":"10.1016/j.actatropica.2025.107523","DOIUrl":"10.1016/j.actatropica.2025.107523","url":null,"abstract":"<div><div>Nearly 32 % of sand fly species recorded in Mexico are related to <em>Leishmania</em> transmission. A correct morphological identification of sand flies is essential to improve epidemiological and control strategies. Wing geometric morphometrics (GM) has proven to be a complementary tool for classical taxonomy, allowing us to explore variations in structure and shape between species. This study evaluated whether the use of wing morphometric traits aids to identify vector sand fly species independently of their geographic distribution. The specimens were identified morphologically using specialized keys, and the right wings were analyzed using 17 landmarks. Principal Component Analysis, Canonical Variate Analysis, and Mahalanobis distances were calculated to quantify morphological differentiation. A total of 305 specimens from nine species were analyzed. Procrustes ANOVA showed significant differences (<em>P</em> &lt; 0.0001) in shape and size for species, as well as significant differences across their distribution between populations of <em>Lutzomyia cruciata</em> (<em>P</em> &lt; 0.0001) and <em>Psathyromyia shannoni</em> (<em>P</em> &lt; 0.0001), respectively. The use of GM tools was effective to separate species at interspecific and intraspecific level, evidencing population differences in vector sand fly species that could favor the transmission of <em>Leishmania</em>.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"262 ","pages":"Article 107523"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142969189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feeding sources of mosquitoes in Galapagos Islands: A potential threat to wildlife conservation","authors":"Carla Andreea Culda ,&nbsp;Luciana Cătălina Panait ,&nbsp;Cristina Daniela Cazan ,&nbsp;Rommel Lenin Vinueza ,&nbsp;Diego Páez-Rosas ,&nbsp;Erika Guerrero Vásquez ,&nbsp;Renato Leon ,&nbsp;Andrei Daniel Mihalca","doi":"10.1016/j.actatropica.2025.107528","DOIUrl":"10.1016/j.actatropica.2025.107528","url":null,"abstract":"<div><div>Vector-borne diseases pose significant threats to both human and animal health, including wildlife, particularly in vulnerable island ecosystems like the Galapagos Islands. This study examines the mosquito community composition around domestic dogs and Galapagos sea lion rookeries across four islands: San Cristobal, Isabela, Santa Cruz, and Floreana. Using BG-Sentinel traps, a total of 292 mosquitoes were collected, identifying three species: <em>Culex quinquefasciatus, Aedes aegypti</em>, and <em>A. taeniorhynchus. Culex quinquefasciatus</em> was the most abundant, with diverse feeding patterns identified through blood meal analysis, revealing host ranges that included domestic chicken, domestic dogs, and sea lions. The presence of <em>Dirofilaria immitis</em> was confirmed in <em>C. quinquefasciatus</em> individuals, indicating a potential risk for heartworm transmission to dogs and to the endangered Galapagos sea lions. Continued surveillance and targeted control measures are crucial for reducing zoonotic disease risks in this fragile ecosystem, emphasizing the need for further research to inform human and animal health prevention strategies.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"262 ","pages":"Article 107528"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142977066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vitro antischistosomal activity of Artemisia species","authors":"Dehan Malan ,&nbsp;Suzanne Van Niekerk ,&nbsp;Cécile Häberli ,&nbsp;Jennifer Keiser ,&nbsp;Frank Van der Kooy","doi":"10.1016/j.actatropica.2025.107535","DOIUrl":"10.1016/j.actatropica.2025.107535","url":null,"abstract":"<div><div>Praziquantel is currently the only effective treatment for schistosomiasis, but several limitations underscore the need for new therapeutic agents. Recent promising <em>in vitro</em> results with <em>Artemisia</em> species and the success of <em>A. annua</em> and its active compound artemisinin in treating parasitic infections warrant the need for further studies. Here we evaluate the <em>in vitro</em> activity of nine <em>Artemisia</em> species, including previously untested species, against newly transformed schistosomula (NTS) and adult <em>Schistosoma mansoni</em>. Three extracts were prepared: an aqueous infusion, a dichloromethane (DCM) fraction of the aqueous infusion, and a DCM extract. All samples were tested for activity at concentrations ranging from 1–25 μg/ml against NTS and the most promising against the adult <em>S. mansoni.</em> All aqueous infusions showed inferior activity against NTS as opposed to the DCM fractions of the infusions and DCM extracts of <em>A. abrotanum, A. arborescens, A. afra,</em> and <em>A. scoparia</em> which displayed superior activity as compared to the positive control praziquantel. The DCM fraction infusions of <em>A. afra</em> (BB) were the most active with IC₅₀ values of 0.35 μg/ml against NTS and 4.5 μg/ml against adult worms. Chemical fingerprinting using High-performance liquid chromatography (HPLC) analysis of the samples revealed some phytochemical similarities and significant differences between the species tested. This study provides supporting evidence of the antischistosomal potential of <em>Artemisia</em> spp. and warrants more in-depth research to identify potential novel therapeutic agents for the treatment of schistosomiasis.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"262 ","pages":"Article 107535"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transcriptome analysis reveals significant discrepancies between two in vitro models of host-trematode interaction","authors":"Ekaterina A. Lishai ,&nbsp;Dmitry V. Ponomarev ,&nbsp;Oxana G. Zaparina ,&nbsp;Maria Y. Pakharukova","doi":"10.1016/j.actatropica.2025.107534","DOIUrl":"10.1016/j.actatropica.2025.107534","url":null,"abstract":"<div><div>Cell models emulating an <em>in vitro</em> parasitic infection can greatly improve our understanding of helminthiases. Nonetheless, it remains challenging to select an appropriate <em>in vitro</em> model to study molecular pathogenesis of infections by trematodes having a complex life cycle. Therefore, adequate models are in high demand. The epidemiologically important foodborne trematode <em>Opisthorchis felineus</em> parasitizes bile ducts of fish-eating mammals, including humans. The human infection leads to chronic inflammation and biliary intraepithelial neoplasia, which is considered precancerous. This study was aimed at evaluating two useful <em>in vitro</em> research tools based on human cholangiocytes’ (H69 cells’) response to the trematode: coculture with live worms or incubation with parasite-derived excretory–secretory products (ESPs). We assessed H69 cells’ proliferation, migration rate, cell cycle shift, and cytokine production. We also conducted genome-wide transcriptome analysis to identify affected cascades of regulatory signaling events. We demonstrated significant discrepancies between the two <em>in vitro</em> models of host–parasite interactions. Although differences between the two models in cell proliferation and cell migration rate were weak, there were substantial differences in the production and release of cytokines IL-6, IL-4, and TNF. A total of 144 genes in H69 cells were found to be differentially expressed after coculture with live worms, whereas 537 genes were differentially expressed after exposure to ESPs. Transcriptomic analysis revealed only 11 common upregulated genes and six common downregulated genes. Functional enrichment analysis of the gene sets also revealed some striking differences between the <em>in vitro</em> models. Our data will contribute to a deeper understanding of biliary neoplasia associated with liver fluke infection. This study underscores the importance of choosing an appropriate <em>in vitro</em> model to accurately emulate host–parasite interactions. The data also highlight the need for further investigation into the pathogenesis of the precancerous biliary lesions associated with liver fluke infection.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"262 ","pages":"Article 107534"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143045443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predictors of encephalitis in children with scrub typhus-associated acute febrile illness","authors":"Neha Srivastava ,&nbsp;Shahnawaz Jamal ,&nbsp;Kamran Zaman ,&nbsp;Hirawati Deval ,&nbsp;Rohit Beniwal ,&nbsp;Bhoopendra Sharma ,&nbsp;Urmila Gupta ,&nbsp;Rajni Kant ,&nbsp;Aman Agarwal ,&nbsp;Umaer Alam ,&nbsp;Manoj Murhekar ,&nbsp;Mahima Mittal","doi":"10.1016/j.actatropica.2025.107525","DOIUrl":"10.1016/j.actatropica.2025.107525","url":null,"abstract":"<div><div>Scrub typhus (ST) is an emerging public health concern in India. Despite being treatable, 20–30 % of acute febrile illnesses (AFI) progress to encephalitis in endemic regions. This study aimed to identify early markers for encephalitis development in children hospitalized with AFI and positive <em>Orientia tsutsugamushi</em> (Ots) serology. This prospective cohort study was conducted during January-December 2018, involved AFI patients (age ≤ 16 years) tested positive for IgM antibodies against Ots. These patients were followed up prospectively to monitor the development of encephalitis. The clinical and biochemical data from ST-AFI cases developed encephalitis were compared with ST-AFI cases did not develop encephalitis. Univariate and multivariate logistic regression analysis were used to determine predictors of encephalitis. Total 41 out of 190 (21.6 %) ST-AFI patients progressed to encephalitis. The multivariate regression analysis identified initiation of antibiotic therapy after more than 5 days from illness onset (OR 4; 95 % CI [1.4–11.6]), vomiting (&gt;3 episodes) (OR: 10.9; 95 % CI [2.3–51.4]), Glasgow Coma Scale (9–12) (OR 6; 95 %CI [1.9–19]), calcium level (≤8 mg/dL) (OR 6.1 95 % CI [1.1–32.6]), serum creatinine (&gt;1 mg/dL) (OR 16.8, 95 % CI [1.5–191.9]), and oxygen support requirement (OR 19.5, 95 % CI[6.4–59.3]) at admission as predictor of encephalitis in ST-AFI cases. The sensitivity and specificity of model was 67.50 % and 93.96 % respectively, Hosmer-Lemeshow test (χ2 = 8.82, <em>P</em> = 0.3584), and an area under the ROC curve of 0.9514. Study found initiation of antibiotic more than 5 days after illness onset, multiple vomiting episodes, low GCS, hypocalcaemia, high creatinine, and oxygen need as predictors of encephalitis in ST-AFI patients.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"262 ","pages":"Article 107525"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unravelling a new focus of spotted fever rickettsioses as causative agents of acute undifferentiated febrile illness in Odisha, a state in eastern coastal India","authors":"Dr CS Premnath ,&nbsp;Shriya Goel ,&nbsp;Prof Bijayini Behera ,&nbsp;Prof Manisha Biswal ,&nbsp;Prof Baijayantimala Mishra ,&nbsp;Prof Rashmi Ranjan Mohanty ,&nbsp;Prof Rashmi Ranjan Das","doi":"10.1016/j.actatropica.2025.107522","DOIUrl":"10.1016/j.actatropica.2025.107522","url":null,"abstract":"<div><div>Spotted fever group <em>Rickettsia</em> (SFGR) infections remain largely under-investigated as causative agents of acute undifferentiated febrile illness (AUFI) in resource-limited settings. Few studies are available on the prevalence of SFGR infections in India, especially in eastern India. In a cross-sectional study conducted in 192 hospitalized adult and paediatric patients with AUFI, the frequency of SFGR using sequential PCR targeting genes encoding citrate synthase (<em>gltA</em>), <em>17 kDa</em> lipoprotein precursor antigen (<em>17kDa</em>), outer membrane proteins A and B (<em>omp A</em> &amp; <em>omp B</em>) was 6.2% (12/192) including 7.4% (8/108) in adults and 4.7% (4/84) in paediatric patients with AUFI. Phylogenetic analysis of SFGR based on the concatenated sequences of <em>omp A-gltA-17kDa-omp B</em> showed that the patients' isolates obtained in the study clustered with <em>Rickettsia conorii</em> str. Malish 7 (AE006914.1). The SFGR cases described here, to the best of our knowledge, are the first human cases diagnosed in Odisha, eastern coastal India that were laboratory-confirmed by molecular detection and sequencing. The findings of this study will be beneficial for designing systematic future studies covering more geographical locations for continued surveillance of SFGR human infections along with vector surveillance.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"262 ","pages":"Article 107522"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142998391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular detection and diversity of Bartonella spp. in non-hematophagous bats from the Peruvian Amazon","authors":"Luis A. Gomez-Puerta ,&nbsp;Juana Ampuero-Riega ,&nbsp;Noelia Medrano-Uchuya ,&nbsp;Siever Morales-Cauti","doi":"10.1016/j.actatropica.2025.107539","DOIUrl":"10.1016/j.actatropica.2025.107539","url":null,"abstract":"<div><div>The <em>Bartonella</em> genus comprises a variety of species capable of infecting a wide range of mammals through hematophagous arthropods, such as fleas, ticks, flies, and lice. Domestic (dogs and cats) and wild (rodents and bats) reservoirs harbor species with zoonotic potential. This molecular study identified the diversity of <em>Bartonella</em> spp. in bats from the Peruvian Amazon. Blood samples from 62 bats were molecularly analyzed for the detection of <em>Bartonella</em> spp. by amplification of the 16S–23S internal transcribed spacer (ITS) region and the citrate synthase (<em>gltA</em>) gene. The ITS region amplification revealed the presence of <em>Bartonella</em> spp. DNA in 12 bats (19.4 %). These bats were four <em>Carollia perspicillata</em>, three <em>Uroderma bilobatum</em>, two <em>Phyllostomus hastatus</em>, a <em>Platyrrhinus infuscus</em>, and a <em>Noctilio albiventris</em>. Partial analysis of the <em>gltA</em> gene successfully assessed <em>Bartonella</em> genetic variants in 11 of the ITS-positive samples. Eleven genetic variants were identified, with differences ranging from 0.3 % to 18.0 % among them. Both a bat N<em>. albiventris</em> and a specimen of <em>C. perspicillata</em> exhibited two variants previously detected in N<em>. albiventris</em> from French Guiana and the bat fly <em>Strebla guajiro</em> collected from <em>C. perspicillata</em> in Brazil. The remaining nine variants correspond to newly identified <em>Bartonella</em> variants in bats. The results revealed a remarkable diversity of <em>Bartonella</em> spp. among bats in the Americas. These findings expand knowledge on the genetic variability of <em>Bartonella</em> infection in these mammals and provide new insights into the ecology of bat-borne <em>Bartonella</em> species.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"262 ","pages":"Article 107539"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143073291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Serological evidence of Crimean-Congo haemorrhagic fever in domestic animals from eight regions of Namibia","authors":"Lourens de Villiers ,&nbsp;Umberto Molini ,&nbsp;Leandra van Zyl ,&nbsp;Siegfried Khaiseb ,&nbsp;Frank Busch ,&nbsp;Klaas Dietze ,&nbsp;Sascha Knauf ,&nbsp;Giovanni Franzo","doi":"10.1016/j.actatropica.2025.107524","DOIUrl":"10.1016/j.actatropica.2025.107524","url":null,"abstract":"<div><div>Crimean-Congo haemorrhagic fever (CCHF) is a viral zoonotic disease endemic to regions of Africa, the Balkans, the Middle East, and Asia, with increasing reports of cases in southern Europe. Human transmission occurs primarily through the bite of infected ticks and by body fluids from infected human. Crimean-Congo haemorrhagic fever virus (CCHFV) affects a broad host range, including both domestic and wild vertebrates. Recent studies have suggested a potential susceptibility of companion animals, posing an additional threat to public health. In the present study, the presence of CCHFV antibodies was evaluated by screening 374 dog and 238 cat serum samples collected from eight Namibian regions using a commercial enzyme-linked immunosorbent assay. Overall, dogs (11.50 %) showed significantly higher odds of seropositivity (OR = 7.60; 95 % CI = 3.02 - 25.51; <em>p</em>-value &lt; 0.001) compared to cats (1.68 %). Most of the positive dogs and all positive cats originated from the Kunene and Hardap regions. No other factors were found to affect seroprevalence. The limited development of farming systems in these regions, combined with the higher roaming activity of dogs, may suggest a greater exposure risk to wild animals or infected ticks. Tick species of the genus <em>Hyalomma</em> are not commonly reported to infest dogs in Namibia, and other tick species may also be involved in transmission. The detection of CCHFV antibodies in dogs and cats in Namibia should be considered by public health authorities as a potential threat, warranting further investigation to identify infection sources and risk factors. While the level and duration of viremia in companion animals, as well as their actual infectivity, remain unknown, efforts should focus on reducing contact between domestic pets, livestock, and wild animals, as well as regular prophylactic tick treatment of pets to prevent or minimise tick infestations.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"262 ","pages":"Article 107524"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142941549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intraspecific genetic variation in the lymphatic filariasis vector Mansonia dives (Diptera: Culicidae) in Thailand: Hidden species or genetically divergent populations?","authors":"Sedthapong Laojun ,&nbsp;Tanasak Changbunjong ,&nbsp;Tanawat Chaiphongpachara","doi":"10.1016/j.actatropica.2025.107526","DOIUrl":"10.1016/j.actatropica.2025.107526","url":null,"abstract":"<div><div><em>Mansonia dives</em> is recognized as a vector for brugian filariasis in Thailand. A recent study analyzing the cytochrome <em>c</em> oxidase subunit I (<em>COI</em>) gene revealed two distinct clades within the <em>Ma. dives</em> population in Thailand. This study aimed to examine the genetic diversity and structure of <em>Ma. dives</em> using the <em>COI</em> gene and the internal transcribed spacer 2 (ITS2) region to determine the presence of distinct species or genetically divergent populations. We analyzed 60 <em>COI</em> and 60 ITS2 sequences from <em>Ma. dives</em> populations in Narathiwat, Ranong, Tak, and Trat. The results showed a nucleotide diversity of 0.019 and a haplotype diversity of 0.979 for the <em>COI</em> gene, while the ITS2 region displayed a nucleotide diversity of 0.005 and a haplotype diversity of 0.545. Phylogenetic and haplotype network analyses of the <em>COI</em> gene identified two genetic lineages: one confined to Trat and another encompassing the other sites. However, species delimitation methods suggested that these genetic differences were insufficient to classify the lineages as distinct species. In contrast, the ITS2 analysis indicated a uniform genetic pattern across all populations. We conducted neutrality tests and mismatch distribution to examine the demographic history. For the <em>COI</em> gene, Tajima's <em>D</em> was slightly positive and non-significant (0.014), while Fu's <em>Fs</em> was negative (−9.750), indicating a potential expansion phase. Conversely, for the ITS2 region, Tajima's <em>D</em> and Fu's <em>Fs</em> were positive and non-significant, suggesting that the population might be in equilibrium or undergoing contraction. Moreover, the mismatch distribution analysis for the ITS2 region was inconclusive. The apparent discrepancies between these markers indicate the presence of genetically divergent populations, rather than distinct species.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"262 ","pages":"Article 107526"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142977118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}