BACKGROUND Massive bee stings can cause systemic manifestations and life-threatening complications. In French Guiana, data on such envenomations are scarce. This study aimed to describe the epidemiology, clinical characteristics, and management of patients presenting to the emergency department. METHODS We retrospectively reviewed medical records of all patients admitted for bee stings over the period 2014-2023 at Cayenne Hospital. A composite variable of systemic involvement was created (neurological, respiratory, hemodynamic and digestive). All analyses were descriptive. An exploratory two-graph receiver operating characteristic (TG-ROC) analysis was used to describe the sensitivity and specificity of sting-count cut-offs for four binary indicators of systemic involvement. RESULTS Among 143 patients included, 40% (n = 57) presented at least one systemic manifestation. The median number of stings was 50 [20-150]. In the exploratory TG-ROC analysis, the cut-offs maximizing the Youden index were approximately 72 stings for digestive and hemodynamic manifestations and 99 stings for neurological and respiratory manifestations, with modest sensitivity (0.50-0.76) and specificity (0.68-0.76). Overall mortality was low (0.7%, n = 1/143). CONCLUSIONS This study provides the first detailed epidemiological and clinical description of massive bee envenomations in French Guiana. Exploratory analyses suggested that systemic manifestations may occur at sting counts below the conventional 200-sting threshold. These findings should not be interpreted as a validated clinical cutoff and require confirmation in prospective multicenter studies.
Oropouche virus (OROV) is an arthropod-borne virus transmitted mainly by Culicoides paraensis midges in Latin America and the Caribbean, though evidence suggests occasional transmission by mosquitoes. Oropouche fever has been reported primarily in the Amazon Basin since the 1950s. In 2024, the number of Oropouche fever cases rose sharply and spread beyond the Amazon region, which has been associated with the emergence of a new reassortant OROV strain. We assessed whether increased case numbers could be explained by enhanced replication or transmission of the reassortant strain in peri-urban Culex quinquefasciatus and Aedes albopictus. Laboratory colonies established from Salvador, Brazil were orally exposed to the ancestral OROV strain BeAn 19991 or the contemporary strain 240023 (10⁴-10⁶ PFU/mL), and viral replication was quantified in bodies, legs, and saliva. To evaluate the influence of mosquito genotype on infection outcomes, infection rates were compared between Ae. albopictus from Salvador City (Brazil) and Houston (USA). In Cx. quinquefasciatus, the outbreak strain replicated less efficiently than the historical strain at low viral doses but not at high infection doses. Regardless of strain or dose, vector competence was extremely low, with only 0-1% of mosquitoes exhibiting infectious OROV particles in their saliva after extrinsic incubation. Conversely, Ae. albopictus showed consistently higher body infection rates for the 240023 strain than for BeAn 19991 at both low and high doses. However, overall transmission potential remained limited: only 0-6.4% of leg or saliva samples were positive across OROV strains and doses. The higher infection rates of the 240023 strain was consistent across both Ae. albopictus genotypes, but infectious saliva was detected only in mosquitoes from the Salvador line (up to 20%) and not in the Houston line (0%). Taken together, this suggests that the recent geographic expansion of OROV is unlikely to be driven by a vector shift from midges to these mosquitoes. Importantly, our findings do indicate higher infectivity of the 240023 strain in Ae. albopictus across different mosquito lines which may have future implications for further adaptation to OROV.
INTRODUCTION Brucellosis is a major zoonotic infection worldwide, with the highest burden reported in the Mediterranean region. The therapeutic role of fluoroquinolones in this disease continues to be controversial. This systematic review and meta-analysis aimed to evaluate the efficacy and safety of fluoroquinolone-containing regimens compared with standard non-fluoroquinolone regimens for the treatment of human brucellosis. METHODS In accordance with PRISMA recommendations, this systematic review and meta-analysis assessed the efficacy and safety of fluoroquinolone-based regimens for treating brucellosis. It was prospectively registered in PROSPERO (CRD420251142019). A comprehensive search of PubMed, Scopus, Web of Science, and the Cochrane Library was carried out, including studies published through August 2025. Randomized controlled trials comparing fluoroquinolones with conventional therapies (such as doxycycline with streptomycin or rifampicin) were included. Therapeutic failure, relapse, adverse events, and time to defervescence were the main outcomes. To compute pooled risk ratios and mean differences with 95%CIs, data were analyzed using STATA v18. The GRADE method and the RoB 2 tool were used to evaluate the risk of bias and the certainty of the evidence. RESULTS The analysis comprised 9 clinical studies with 602 brucellosis patients. When compared to standard regimens, fluoroquinolone-based regimens were linked to a significantly higher risk of therapeutic failure (RR = 2.11, 95% CI: 1.26-3.51; P = 0.004) and a higher, though not statistically significant, risk of relapse (RR = 1.88, 95% CI: 0.94-3.74; P = 0.07). No statistically significant between-study heterogeneity was observed for either outcome (I² = 0%). Subgroup analyses showed a significantly increased risk of therapeutic failure in patients with uncomplicated brucellosis and in studies with treatment durations >8 weeks, although between-subgroup differences were not statistically significant. On the other hand, no statistically significant difference in adverse events was observed between fluoroquinolone-based and standard regimens under the random-effects model (RR = 0.62, 95% CI: 0.29-1.33; P = 0.22). Although the point estimate favored fluoroquinolone-based regimens, the confidence interval included the null effect. Fluoroquinolone-based regimens were also associated with a significantly longer time to defervescence compared with standard regimens (MD = 1.20 days, 95% CI: 0.66-1.74; P < 0.001). The certainty of evidence was moderate for therapeutic failure, and time to defervescence, and low for relapse and adverse events according to the GRADE evaluation. CONCLUSION Compared with conventional doxycycline-based combinations, fluoroquinolone-based regimens were associated with a higher risk of therapeutic failure and longer time to defervescence, while the overall risk of relapse did not differ significantly. No significant difference in adverse events was observed with the random-effects model, although the point estimate favored fluoroquinolone-based regimens. Overall, these findings do not support the routine use of fluoroquinolones as first-line therapy for adult brucellosis. Further well-designed randomized controlled trials are needed.
Zoonotic mosquito-borne viruses, including West Nile, Rift Valley fever and Japanese encephalitis viruses, present a substantial public health burden in some countries, with transmission involving complex interactions between multiple vector and host species, making control difficult. While host community composition is known to affect transmission, the role of host community structure coupled with mosquito aggregation behaviour remains poorly understood. Motivated by furthering understanding of potential Japanese encephalitis virus transmission routes and persistence in contexts where cattle – dead-end hosts – are dominant in the community, we developed a patch model in which host distributions and the resulting mosquito biting allocation among patches are fixed within each simulation. This framework represents mosquito host-seeking across two scales: long-range aggregation toward host-dense patches and short-range host species choice determined by local host availability and innate vector preference. Using this model, assuming that vectors prefer dead-end hosts (choosing them 90% of the time if given an equal choice of other hosts), we explored the potential effect of host clustering, patch fragmentation, and the strength of mosquito aggregation on the basic reproduction number. Our results show that identical host communities can yield very different transmission outcomes depending on how they are distributed and the level of mosquito aggregation. Under circumstances where dead-end hosts are preferred by vectors, if competent hosts are clustered and mosquitoes aggregate strongly, transmission may be amplified compared with uniformly distributed hosts and vectors. If dead-end hosts are clustered, transmission may be diluted as mosquitoes aggregate in patches where dead-end hosts are dominant in the host community. Fragmentation effects are context-dependent: when competent hosts are clustered and mosquitoes aggregate, increasing patches increases transmission. When dead-end hosts are clustered, transmission decreases under strong mosquito aggregation with increasing number of patches. These findings highlight that variations in the local spatial context of host-vector interactions can lead to variations in disease risk. Locally-informed surveillance and targeted interventions may therefore be important in attempts to prevent outbreaks of zoonotic mosquito-borne viruses.
The development of an efficacious vaccine against Plasmodium vivax malaria remains a top global health priority. P. vivax forms hypnozoites, dormant forms of the parasite in the liver that can become reactivated after a few months or even years, causing relapse malaria and enhancing transmission. Therefore, targeting antigens expressed during the pre-erythrocytic stages offers the potential to prevent clinical malaria from both primary and relapse infections. The circumsporozoite protein (CSP) is the leading pre-erythrocytic vaccine candidate and forms the basis for the current P. falciparum malaria vaccines RTS, S and R21/Matrix M. Studies have shown that in P. vivax , CSP attributes limited protection, highlighting the need to identify additional pre-erythrocytic antigens to improve vaccine efficacy. Evaluation of new candidates often requires human volunteers, making initial screening complex and highlighting the need for robust preclinical models. In this study, we generated transgenic P. berghei parasite lines as research tools to investigate the potential efficacy of two P. vivax pre-erythrocytic vaccine candidates, SSP3 and SPECT1. The chimeric Pb-Pv SSP3 and Pb-Pv SPECT1 lines showed normal development throughout the parasite life cycle, in both mice and mosquitoes. Antisera raised against recombinant Pv SSP3 and Pv SPECT1 using TitreMax Gold adjuvant exhibited reduction in sporozoite invasion of hepatocytes in vitro , with mean inhibitions of 27% and 14%, respectively. In vivo sporozoite challenge studies showed sterile protection in 10% of mice immunized with r Pv SPECT1, whereas r Pv SSP3 provided no detectable protection. Although substantial protection was not observed for either antigen under the conditions tested, the transgenic P. berghei lines generated in this study serve as useful platforms for evaluating the efficacy of these antigens as vaccine candidates across different delivery systems and adjuvanted formulations.
