Lymphocytic choriomeningitis virus (LCMV) is a neglected zoonotic arenavirus primarily transmitted by house mice (Mus musculus). In humans, LCMV infection can cause encephalitis, meningitis, or severe birth defects. In New World (NW) primates, LCMV causes acute and fatal callitrichid hepatitis (CH). We detected a continuous occurrence of LCMV lineages I and II in the house mouse population of a zoo, with the first occurrence of lineage II in 2014 and lineage I in 2021. Although the total LCMV...

Aedes albopictus is a primary vector of multiple arboviruses, including dengue, chikungunya, yellow fever, and Zika virus. Its control relies heavily on pyrethroid insecticides. The V1016G mutation in the voltage...

Tsetse flies are major vectors of trypanosomes in Sub-Saharan Africa, posing risks to livestock and human health. This study investigated the diversity, distribution, and infection rates of tsetse species, as well as the genetic diversity of drug resistance-associated trypanosome strains in Kenya. Flies were collected from Kwale, Taita-Taveta, Kajiado, Narok, and Turkana counties between November 2024 and February 2025. DNA analyses targeting rRNA and transporter genes (TbAT/P2, E6M6, DMT, TcoAde2) identified infections and resistance-associated mutations among 4693 sampled flies. Apparent density was highest in Kwale (101.52 flies/trap/day) and lowest in Turkana (1.18). Species distribution varied by county, with Kwale dominated by G. pallidipes, G. austeni, and G. brevipalpis; Taita-Taveta G. pallidipes, and G. brevipalpis; Kajiado G. pallidipes and G. longipennis; Narok G. pallidipes, G. brevipalpis, G. swynnertoni, and G. longipennis; and Turkana only G. pallidipes. Trypanosoma congolense was most prevalent, especially in Kwale, while T. brucei was common in Kajiado and Kwale. G. brevipalpis, G. austeni, and G. pallidipes showed higher infection risks. Drug resistance-associated T. congolense strains were found in Kwale and Taita-Taveta, with TcoAde2 and E6M6 gene diversity linked to Kenyan isolates. These findings highlight the need for targeted control of high-risk tsetse species and drug-resistant trypanosomes in Kenya.

Among the Ixodid ticks, Hyalomma anatolicum is a well-known vector that transmits various pathogens to terrestrial and semi-terrestrial vertebrates including humans, and its population differ in ecology and vector competence. Expansion of this tick to new areas changes the genetic structure, and lead to affect the vector-pathogen interaction and disease outcomes. The present study was designed to infer the haplotype diversity, demographic dynamics, gene flow and genetic differentiation, and...

As a global hub for trade and tourism, Shanghai faces escalating risks of dengue fever due to imported and local transmission. Aedes albopictus, the primary dengue vector in the region, is predominantly controlle...

by Marina Meester, Cecilia Valenzuela Agüí, Tijs J. Tobias, Renate W. Hakze van der Honing , Claire Guinat, Martijn Bouwknegt, Louis du Plessis, Egil A.J. Fischer, Mirlin Spaninks, Tanja Stadler, Wim H.M. van der Poel, Arjan Stegeman Worldwide, many pig farms are affected by hepatitis E virus (HEV) genotype 3, a zoonotic virus that causes hepatitis in humans. People can become infected after eating contaminated pork, making HEV control in pig farms crucial for public health. However, knowledge of HEV transmission dynamics and control options within farms is limited. Our findings reveal that HEV persists in the farm environment, enabling transmission between pigs separated in space and time. We investigated HEV transmission on two Dutch finishing farms for nine months in 2022. In both farms, samples from three compartments (confined rooms), holding 12 pens with pigs each, were collected and tested weekly across three batches (consecutively housed groups of pigs). Additionally, at least one sample per HEV-positive pen was sequenced per batch, retrieving 89 near-complete sequences. We integrated epidemiological data on duration and timing of infection with phylogenetic data to quantify transmission. We observed phylogenetic clustering of pens per compartment in both farms. In farm A, some sequences from different compartments and different batches also clustered, suggesting transmission between pigs housed separately. In farm B, only one compartment became HEV-positive during one batch. Within that compartment, between-pen transmission was efficient, with an effective reproduction number (Re) of 3.6 (95% HPD interval 1.3–6.7). The other compartments and batch may have remained HEV-negative thanks to stringent biosecurity measures applied on that farm. In farm A, the Re’s for transmission between pens within and across compartments were not significantly above 1, yet all sampled pens became positive in all batches. A combination of transmission routes, in conjunction with persistence of HEV in the environment, is required to explain why all pens tested positive. These findings show not only how HEV effectively spreads without pigs sharing housing, yet also that reduction of HEV’s zoonotic risk may be achieved by improved biosecurity within farms.

Onyong-nyong virus (ONNV) is a mosquito-borne alphavirus first isolated in Uganda in 1959. Since its discovery, ONNV has caused several outbreaks in Africa, manifesting clinically as fever, rash, and joint/muscle pain lasting months. Currently, we have a limited understanding of ONNV infection and disease in relevant animal models, which restricts the evaluation of vaccines and therapeutics. In 1967, Binn et al. reported that infection of rhesus macaques (RMs) with ONNV failed to induce viremia in two animals. This may be attributed to the potential attenuation of the virus through extensive passaging. To mitigate this issue, we constructed an infectious clone from the sequence of ONNV-UVRI0804 (ONNV0804), a 2017 clinical isolate from a febrile patient in Uganda. This strain demonstrated high pathogenicity in immunocompetent mice, resulting in an earlier and more severe onset of disease and significantly higher viremia compared to a highly passaged control strain ONNVUgMP30. In the current study, three male and three female rhesus macaques were subcutaneously inoculated with ONNV0804. All animals became viremic at 2 days post inoculation (dpi). Both classical and nonclassical monocytes were activated (CD169+), peaking at 3 dpi, which corresponded with the peak of viremia. Additionally, CD4+ and CD8+ effector memory T cells and memory B cells began proliferating in peripheral blood by day 7, peaking at day 10, which also corresponded to the timing of neutralizing antibody development, indicating a robust adaptive immune response to ONNV0804. Finally, key clinical disease manifestations were recapitulated, including lymphadenopathy and histological features of early-stage arthritis. Taken together, rhesus macaque infection with ONNV0804 clinical isolate is a promising model for investigating immune responses to alphaviruses and evaluating vaccines to protect against future epidemics.

Background: In sub-Saharan Africa, Plasmodium falciparum is unequivocally responsible for almost all malaria cases and deaths. However, the long-neglected human P. vivax, P. ovale, and P. malariae parasites also emerge as relevant, though their prevalence and contribution to the burden of the disease are very poorly appreciated. This study aimed to bridge this gap and surveyed the circulation of non-falciparum malaria parasites among febrile patients in four regions in south Senegal. Methods: Blood samples were obtained from 1990 febrile patients during the malaria transmission seasons of 2020, 2021, and 2022 in four southern regions in Senegal (Kedougou, Kolda, Tambacounda, and Ziguinchor). Genomic DNA was isolated and tested for Plasmodium infections by using a combination of Plasmodium genus-specific qPCR and Plasmodium species-specific nested PCR. Frequencies and distribution of Plasmodium species according to region, period, and patient demographics were analyzed using R. Spatial patterns of infection were further explored and visualized with QGIS software version 3.30.2. Results: The Plasmodium positivity rate was 73.43% of which 67.92% were unique Plasmodium species infections and 32.08% were co-infections by two or three Plasmodium species. The results described the ongoing circulation of all non-falciparum species in three of the four study regions, the non-detection of P. vivax and P. malariae parasites among the samples tested in Ziguinchor, the first evidence of non-falciparum infections in Kolda and Tambacounda, as well as the first report of P. ovale in Ziguinchor. Conclusions: Our data call on clinicians to account for these species in clinical prognoses, but also on the National Malaria Control Programme to consider these species in their policy of reducing the incidence of the disease with a view to eliminating malaria in Senegal.

Background: Anopheles funestus, a major vector of malaria in Africa, has proven difficult to colonize in laboratory settings, impeding research on its biology and control. After several attempts, our team recently succeeded in colonizing a strain of An. funestus from Tanzania (FUTAZ). The objective of this study was to analyse the key fitness and genotypic characteristics of these mosquitoes during multiple filial generations of laboratory adaptation and compare them to wild An. funestus from Tanzania and a pre-existing colony of An. funestus from Mozambique (FUMOZ). Methods: Measures of mating success (percentage of female mosquitoes inseminated), body size (wing length), fecundity (number of eggs laid per female), and insecticide susceptibility (percentage of 24-hour mortality after exposure to insecticides) were compared between the newly established colonies of Tanzanian An. funestus (FUTAZ colonies), the long-established FUMOZ colonies, and a colony of Anopheles arabiensis maintained in the same laboratory. The maternal lineages of the An. funestus mosquitoes were investigated through a hydrolysis probe analysis of their mitochondrial DNA to identify distinct clades, I and II. Additionally, other intragenomic variations were examined through a PCR analysis of restriction fragment length polymorphisms (RFLP) on the third domain of 28S ribosomal DNA. These molecular markers were used to compare the FUTAZ colonies, FUMOZ colonies in Tanzania and South Africa, and the wild-collected An. funestus from Tanzania. Result: The mating success and body size of FUTAZ females declined significantly from filial generations F1 to F6 relative to the founder population (F0), but then increased from F7 onwards eventually matching FUMOZ by F9. Fecundity was similar across all colonies tested. However, it took significantly longer for 50% of the females in the FUTAZ and FUMOZ colonies (over 10 days) to mate compared to females in the An. arabiensis colony (approximately 5 days). Insecticide resistance appeared to be lost during colonization, but this varied with insecticide classes. Majority of mosquitoes in the FUTAZ colony, as well as the wild-caught Tanzanian An. funestus belonged to Clade I (80.4-89.4%) and RFLP type "Y" (90.5-91.4%), while the FUMOZ colonies were mostly Clade II (65.5-88.5%) and RFLP type "MW" (90.5-91.5%). Conclusion: This study suggests that the mating success and body size of An. funestus decreases significantly during the early stages of colonization, then increase as the mosquitoes adapt to laboratory conditions. It is therefore crucial to have a large enough founder population to persist through these early generations in order to achieve stable colonization of An. funestus. The Clade and RFLP genotyping demonstrated the genetic similarities between the FUTAZ mosquitoes and wild-caught Tanzanian An. funestus, but also showed that the new colony can be distinguished from the FUMOZ colony.

To preserve proteome homeostasis and survive at higher-than-optimal temperatures, organisms have evolved the conserved heat shock (HS) response (HSR), characterised by increased expression of specific chaperone-encoding genes. In the human blood, malaria parasites are frequently exposed to elevated temperatures associated with host fever episodes. The protective HSR of Plasmodium falciparum, the parasite that produces the vast majority of malaria clinical cases and deaths, is regulated by the transcription factor AP2-HS. Here, we systematically investigated the conditions that trigger the AP2-HS-dependent HSR and found that even mild HS conditions that do not compromise parasite viability can activate this response. Similar to other organisms, activation of the HSR in P. falciparum is rapid, as it was observed after an only 10 min HS. Artemisinin (ART), a drug that produces proteome damage, also triggered the HSR, indicating that activation of the malarial HSR is not restricted to thermal stress. The AP2-HS-dependent HSR can be activated in all asexual blood stages, with the exception of very young rings, but not in intermediate or mature gametocyte stages. Accordingly, these gametocyte stages are highly sensitive to HS. Since mature gametocytes are the only stage that can mediate human-to-mosquito transmission, these results suggest that malaria patients with high fever may become transiently uninfective.

BACKGROUND: Endectocides are a novel vector control tool that reduce the survival and fertility of blood sucking arthropods that feed upon treated humans or animals. Ivermectin mass drug administration is under evaluation as a complementary strategy for malaria vector control. The BOHEMIA consortium conducted two cluster-randomized trials, one in Mozambique, reported here and one in Kenya, reported elsewhere.

Genome three-dimensional organization is essential for eukaryotic gene expression. The chromosomes of the pathogen Trypanosoma brucei contain hundreds of silent variant surface glycoprotein (VSG) genes in subtelomeric regions. T. brucei transcribes a single VSG gene and periodically changes the VSG expressed, altering its surface coat to escape host antibodies by antigenic variation. We show that T. brucei core and subtelomeric chromosome compartments are separated by distinct boundaries and...

Culex modestus is a primary vector of West Nile virus (WNV) in Europe, feeding on both avian and mammalian hosts. Since its rediscovery in the UK in Kent in 2010, its range has been reported throughout the coasta...

Publication date: Available online 23 November 2025 Source: Acta Tropica Author(s): Suitombaye Noubaramadji Yamti, Amine Akouya, Koutaya Dezoumbe, Leabaneng Tawe, Setho Ruth Taboka Kgakatsi, Abel Dafogo Djibagaou, Monique Routoubé, Giulia Cappelli, Sabrina Atturo, Ghyslaine Bruna Djeunang Dongho, Gianluca Russo, Guy Rodrigue Takoudjou Dzomo, Vittorio Colizzi, Giacomo Maria Paganotti

Acquiring data about ecology over long periods of time and large geographical areas is often difficult, expensive, and takes a long time. Here, we explore whether, through millions of daily posts on social networks, we could be constantly and unconsciously accumulating data regarding important biological patterns over the years. Data analysis from generalist social networks has been successfully applied in different research fields, most notably in political science and epidemiology. Here, we evaluate their potential and drawbacks for studying biological patterns of other organisms over time. To that end, we used millions of posts on Twitter (currently X), over 11 years, on four different insect groups: cockroaches, crickets, Monarch butterflies, and mosquitoes. Our results show that through millions of daily tweets, we could identify temporal periodic patterns that reflect their unique known phenology of the four insect taxa studied. Given the 11-year span of the dataset, we could also track changes in their patterns over the years that might be related to environmental factors. Using a sentiment analysis, we could also characterize the emotions of people towards these animals, which is important for the design of awareness campaigns. We also discuss the limitations of these data, such as the potential that social media data might have for spatial tracking of migrations. In summary, we show compelling evidence for the use of social network data for biologists and provide a theoretical and practical framework for exploring these sources of data.

by Julia W. Muita, Joel L. Bargul, JohnMark O. Makwatta, Ernest M. Ngatia, Simon K. Tawich, Daniel K. Masiga, Merid N. Getahun

Francisella tularensis is the causative agent of tularemia, a zoonotic disease named after the city of Tulare, California. Symptoms include sudden fever, chills, fatigue, and swollen lymph nodes, among others, and without treatment it is very serious or even fatal. In addition, F. tularensis is considered a potential bioterrorism threat due to its high infectivity and lethality. Ribosomes are key targets for many classes of antibiotics. In this study, we examined the F. tularensis ribosome and determined its structure at 2.5A resolution using cryo-electron microscopy. Notably, we observed the stress-induced ribosome-associated inhibitor A (RaiA) protein bound to the ribosome. RaiA functions as a molecular hibernation factor, inhibiting bacterial translation in response to stress or nutrient deprivation. This mechanism parallels that described in the model organism Escherichia coli and in several pathogenic bacteria, such as Staphylococcus aureus. Furthermore, we solved structures of the antibiotics chloramphenicol and gentamicin bound to the F. tularensis ribosome. Collectively, these results provide structural insights that highlight previously unexplored opportunities for therapeutic intervention.

CONCLUSIONS: Aedes aegypti in Pakistan belong to a globally monophyletic lineage and show moderate mitochondrial diversity with higher population structure than the global population. The lack of detected Wolbachia infections suggests that natural strains are either absent or occur at very low prevalence. These findings provide a baseline for surveillance and support integrating Wolbachia-based biocontrol alongside conventional interventions in Pakistan.

Niemann-Pick type C1 (NPC1) disease is a rare neurodegenerative disorder linked to defective cholesterol biosynthesis and altered lipid regulation. In patients, the most common variant in the Npc1 gene is a missense mutation that leads to a misfolded and non-functional NPC1 protein. We used a mouse model carrying this mutation (I1061T, Npc1tm(I1061T)Dso) to investigate the olfactory system since olfaction is often negatively impacted in many neurodegenerative disorders, with olfactory decline frequently preceding other neurodegenerative symptoms. We characterized cell types in the olfactory epithelium (OE) in wild-type, heterozygous, and homozygous Npc1tm(I1061T)Dso mice to analyze neurodegeneration at two time points, namely 36 and 60 days after birth. In homozygous Npc1tm(I1061T)Dso mice the density of olfactory sensory neurons (OSNs) at 36 days after birth is decreased compared to wild type and heterozygous mice while the density of immature OSNs and the stem cell niche seems to not be affected. In the OE of the homozygous Npc1tm(I1061T)Dso mice we found an increased density of apoptotic cells and clear sign of neuroinflammation in macrophage/microglia infiltrating the OE. We analyzed the lipid profile of OE by positive MALDI-TOF and found increased markers of neuroinflammation homozygous Npc1tm(I1061T)Dso mice. These structural changes affected the functionality of the OE since we found reduced odorant responses in Npc1tm(I1061T)Dso mice compared to wild type. Additionally, our olfactory behavioral tests revealed deficits in odor-guided food-seeking tests in Npc1tm(I1061T)Dso but not in the wild type and heterozygous mice. We also analyzed the olfactory abilities of a family of three with the parents carrying two different mutations of the Npc1 gene, with the child carrying both mutations and being diagnosed with NPC1 disease. Using the Sniffin Sticks olfactory test, we found that all three were hyposmic with the child having severe hyposmia. Our work extensively characterized the OE structurally and functionally proposing it as a sentinel to monitor disease progression. We are the first to show that NPC1 patients are affected by severe hyposmia and that heterozygous parents could be monitored for olfactory abilities since it could be a biomarker for future neurological disorders.

Mammarenaviruses (MaAv) cause persistent infection in their natural rodent hosts across the world and via zoonotic events can cause severe disease in humans. Thus, the MaAv Lassa virus (LASV) in Western Africa and Junin virus (JUNV) in the Argentinean Pampas cause hemorrhagic fever diseases with significant case fatality rates in their endemic regions. In addition, the globally distributed MaAv lymphocytic choriomeningitis virus (LCMV) is an underrecognized human pathogen of clinical significance capable of causing devastating infections in neonates and immunocompromised individuals. Despite their impact on human health, there are currently no FDA-approved vaccines or specific an-tiviral treatments for MaAv infections. Existing anti-MaAv therapies are limited to the off-label use of ribavirin whose efficacy remains controversial, hence, the significance of developing novel therapeutics to combat human pathogenic MaAv. We employed a high-throughput cell-based infection assay to screen the Pandemic Response Box, a col-lection of 400 diverse compounds with established antimicrobial activity, for MaAv in-hibitors. We identified Ro-24-7429, an antagonist of the HIV-1 Tat protein and RUNX Family Transcription Factor 1 inhibitor; WO 2006118607 A2, a dihydroorotate dehy-drogenase inhibitor; and verdinexor, a novel selective inhibitor of nuclear export (SINE) targeting the CRM1/XPO1, as potent anti-MaAv compounds. Consistent with their distinct validated targets, verdinexor and WO 2006118607 A2 exhibited a very strong synergistic antiviral activity when used in combination therapy. Our findings pave the way for the development of verdinexor as a potent host-directed antiviral against MaAv, which could be integrated into the development of combination therapy with direct-or host-acting antivirals to combat human pathogenic MaAv.

Chronic Trypanosoma cruzi infection remains a major cause of preventable cardiomyopathy in Latin America, yet prospective data from endemic rural populations after the interruption of domestic transmission are limited. This study characterizes the long-term clinical evolution, treatment response, and cardiovascular outcomes of 80 adults with confirmed chronic infection from Mogotes, Santander, Colombia. Participants were followed from 2015 to 2023 by means of standardized clinical, electrocardiographic, echocardiographic, serological, and qPCR evaluations. The primary outcome was progression from the indeterminate to the cardiac form; secondary outcomes included worsening to advanced cardiomyopathy and cardiovascular events. During 422 person-years of follow-up (median 61.5 months), 14 participants (17.5%) experienced clinical progression (3.3 per 100 person-years) and seven (9%) died (1.7 per 100 person-years). Benznidazole treatment was initiated in 42 participants and completed by 34 (81%); only 4 of 34 (12%) remained qPCR-positive after one year, compared with 21% among untreated individuals. Progression from the indeterminate form occurred in one participant (0.7 per 100 person-years), whereas deterioration clustered among those with baseline cardiomyopathy. Despite low mortality, stage-dependent progression persisted, highlighting the need for early diagnosis, treatment adherence, and sustained molecular and cardiac monitoring in post-certification settings. These findings provide rare longitudinal evidence on chronic T. cruzi infection under real-world endemic conditions.

Leishmaniasis is a vector-borne disease endemic in more than 99 countries and manifests primarily as cutaneous, mucocutaneous, or visceral forms. This study aimed to assess the impact of Leishmania RNA virus 2 (LRV2) on immune responses and disease pathology in mice infected with Leishmania tropica. BALB/c mice were inoculated subcutaneously in the right hind footpad with L. tropica either lacking or carrying LRV2 (LRV2- and LRV2 + groups, respectively) and monitored for 24 weeks. Footpad and...

Current treatment for visceral leishmaniasis (VL) is associated with toxicity, a high cost, and the emergence of drug-resistant parasite strains. Moreover, no human vaccine is available. In this context, immunotherapeutics combining vaccination and chemotherapy have emerged as a promising alternative. In this study, we combined a recombinant chimeric protein (ChimT) with the adjuvant 3-O-desacyl–monophosphoryl lipid A (MPLA) and the antileishmanial drug miltefosine (Milt) and used it to treat Leishmania infantum-infected mice. Parasitological, immunological, and toxicological assays were performed at 1 and 30 days post treatment. The ChimT/MPLA/Milt combination was the most effective therapeutic regimen, inducing robust Th1-type cellular and humoral immune responses, as demonstrated by increased levels of IFN-γ, IL-12, and TNF-α cytokines, nitrite, and IgG2a antibodies. These responses were associated with significant reductions in parasite load across various organs. Furthermore, the treatment showed low renal and hepatic toxicity at both evaluation time points. By contrast, ChimT alone, ChimT/MPLA, and Milt induced lower immunological and parasitological responses when compared with the ChimT/MPLA/Milt group. The results observed at 1 and 30 days post treatment demonstrated the potential of ChimT/MPLA/Milt combination against VL.

We evaluated the effects of climatic factors, host and parasite species richness, and their phylogenetic and functional diversity on the nestedness and modularity of mammal-flea interaction networks from four biogeographic realms. We also tested for the associations between pure structural network dissimilarity (i.e., dissimilarity between host-sharing-by-fleas networks, Dh, or dissimilarity between flea-sharing-by-hosts networks, Df) and environmental dissimilarity, and host and flea...

Aedes albopictus is a primary vector of multiple arboviruses, including dengue, chikungunya, yellow fever, and Zika virus. Its control relies heavily on pyrethroid insecticides. The V1016G mutation in the voltage...