Abstract:

Concurrent evaluation of the antiparasitic efficacy of synthetic and natural compounds can provide novel insights into the development of anti-Toxoplasma drugs. We assessed 16 synthetic compounds and fractions derived from the leaves of two Tabebuia tree species for their in vitro activity against live parasites, employing strains that express green fluorescent protein and specific identification of bradyzoites with an anti-BAG1 monoclonal antibody. This study successfully identified several promising synthetic compounds with potent anti-Toxoplasma activity and favorable in vitro selectivity profiles, notably pyrazoline 2 and thiazolidinone 9. One thiazolidinone compound exhibited significant activity against extracellular tachyzoites, whereas one tree fraction demonstrated excellent activity against both tachyzoites and bradyzoites. Additionally, their in silico ADMET properties suggest their potential for good in vivo performance and CNS penetration. Although the natural extracts showed less potency in their crude form, they provide a basis for future purification efforts. The simultaneous evaluation of compounds sourced from diverse discovery pipelines can offer valuable insights into the development of drugs that target various biological pathways.

Abstract: This scoping review of original literature published before 1 March 2025 examined the de-mographic, clinical and simple laboratory findings associated with the development of severe leptospirosis. The definition of severe leptospirosis varied in different studies, but for the purposes of this review it included death or patients with a more complicated clinical course. There were 35 articles that satisfied the review’s inclusion criteria. Increasing age was asso-ciated with severe disease in 7 studies. Abnormal respiratory examination findings (18 stud-ies), hypotension (11 studies), oliguria (8 studies), jaundice (7 studies) and altered mental status (4 studies) also helped identify high-risk patients. Abnormal laboratory tests – specifi-cally the complete blood count (17 studies), measures of renal function (16 studies) and liver function (14 studies) – were also associated with severe disease. There was geographical heterogeneity in the clinical phenotype of severe disease, but the presence of hypotension, respiratory or renal involvement had prognostic utility in all regions. Simple bedside findings and basic laboratory tests can provide valuable clinical information in patients with lepto-spirosis. Integration of these indices into early risk stratification tools may facilitate recogni-tion of the high-risk patient and expedite escalation of care in resource-limited settings where most cases of life-threatening leptospirosis are seen.

Abstract: Lung involvement in patients with leptospirosis is associated with a more complicated disease course. However, the demographic and clinical associations of lung involvement are incompletely defined, and its optimal management is uncertain. This retrospective study examined consecutive patients admitted to a referral hospital in tropical Australia, with laboratory-confirmed leptospirosis between January 2015, and June 2024. Lung involvement was defined as new lung parenchymal changes on chest imaging at any point during the patients’ hospitalisation. The demographics, clinical findings and clinical course of the patients with – and without – lung involvement were compared. The median (interquartile range (IQR)) age of the 109 patients was 39 (24-56) years; 93/109 (85%) were male. Lung involvement was present in 62/109 (57%), 55 (89%) of whom had no documented comorbidities. Patients with lung involvement re-ceived antibiotics later in their disease course than those without lung involvement (median (IQR): 5 (4-6) versus 3 (2-5) days of symptoms, p=0.001). Lung involvement was frequently just one component associated with multi-organ failure: patients with lung involvement were more likely to require inten-sive care unit admission than patients without lung involvement (41/62 (66%) versus 15/47 (32%), p< 0.001). Overall, 30/109 (28%) satisfied criteria for acute respiratory distress syndrome (ARDS) and 26/109 (24%) developed pulmonary haemorrhage. Patients with lung involvement received cautious fluid resuscitation, vasopressor support and prompt initiation of additional supportive care – including me-chanical ventilation, renal replacement therapy and extracorporeal membranous oxygenation – guided by the patients’ physiological parameters and clinical trajectory. All 109 patients in the cohort were alive 90 days after discharge. Life-threatening lung involvement can complicate leptospirosis in young and otherwise well individuals. However, in Australia’s well-resourced health system excellent outcomes can be achieved using a standard contemporary approach to the management of a patient with undif-ferentiated infection while a confirmed diagnosis of leptospirosis is awaited.

Abstract: Background: The global incidence of dengue has markedly increased over the last decades. Consequently, the risk for infection has increased significantly. This resulted in record numbers of imported cases in various European countries and elsewhere in 2024 and large numbers of travellers with dengue are treated in the endemic destination countries. Methods: In early 2023, TAK003, a novel, live attenuated vaccine against dengue became available in Germany. At the Berlin Centre for Travel & Tropical Medicine, we delivered 56,459 doses during the first 24 months from February 2023 until February 2025. In order to gain data on the tolerability of the vaccine in travellers, an active follow-up survey was initiated. Results: 30,306 (53.7%) vaccinees agreed to being contacted. Out of those 11,827 (39.0%) completed the anonymous questionnaire ≥4 weeks after the vaccination. Overall, 6,856 (58.0%) were female, 565 subjects (4.8%) reported to have had a prior dengue infection. The average age was 42.1 years (median 35 years, range 4-86 years). The journey to an endemic area had been completed by 6,309 subjects before answering the questionnaire and among those, 46 (0.7%) reported a dengue infection while abroad. All cases were mild, no complications were reported. TAK003 was applied with other vaccines in 7,363 (62.3%) travellers. Local adverse reactions were reported by 5,263 (47.5%) of subjects, mostly local pain. Systemic reactions were reported by 4,891 subjects (41.4%), most frequently fatigue, myalgia, and flu-like symptoms. The majority of adverse events manifested in the second week after vaccination (average 9.3 days, median 8 days) and were mostly limited to a duration of 1-3 days. A macular exanthema was described by 1,844 subjects (15.6%), typically during the second week after the vaccination. Conclusions: Side effects were frequently reported but generally well tolerated. Age groups above 50 years showed a decline of reactogenicity. Co-vaccination was frequent and led to an increase of systemic adverse events. Denominator data of the study population suggest a strong reporting bias towards adverse events. This survey adds evidence on the chronology and characteristics of adverse events associated with TAK003 and may support decision making when vaccinating dengue naïve travellers.

Abstract: Cystic echinococcosis (CE) is an endemic zoonotic disease caused by Echinococcus granulosus, which forms cysts in ungulates’ intermediate hosts. Humans are accidental hosts, and CE affects more than one million people worldwide. Imaging remains the diagnostic gold standard, outperforming serological methods. This study presents an in silico analysis of two glyceraldehyde-3-phosphate dehydrogenase (GAPDH) isoenzymes from E. granulosus (EgGAPDH), isolated from a parasite cell line (EGPE). EgGAPDHs were recognized by sera from CE patients, identified through LC-MS/MS and PCR from metacestodes’ cattle liver. One isoenzyme is intracellular (IC) (UniProt: W6UJ19), and the other is extracellular (EC) (UniProt: W6V1T8). GAPDH is involved in host-parasite interactions and metabolic processes. We characterized the physicochemical properties, linear epitopes, and amino acid domains of EgGAPDH, its hosts and other parasites. W6UJ19 emerged as the most promising isoenzyme as a marker of infection. Molecular dynamics simulations of isoenzymes, performed in the presence or absence of two bisphosphonates (BPs), revealed how drug binding alters conformational epitopes and suggest that enzymatic activity is more likely associated with W6UJ19. Binding affinity analysis using the MMPBSA method revealed that etidronate (EHDP) binds EgGAPDH with greater affinity than phosphate (Pi) and alendronate (AL), in the order: EHDP > Pi > AL.

Abstract: Leptospirosis is a globally distributed zoonotic disease caused by pathogenic bacteria of the Leptospira genus. Genome editing in Leptospira has been difficult to perform. Currently, the functionality of the CRISPR-Cas system has been demonstrated in species such as Leptospira interrogans. However, the different CRISPR-Cas systems present in most of the 77 species are unknown. Therefore, the objective of this study was to identify the CRISPR-Cas systems present in the genomes of the Leptospira genus using bioinformatics tools. Methods: bioinformatics workflow was followed: the genomes were downloaded from the NCBI database, Cas proteins detection was carried out using the CRISPR-CasFinder and RAST web servers, functional analysis of Cas proteins (InterProScan, ProtParam, Swiss Model, Alphafold3, Swiss PDB Viewer, and Pymol), conservation pattern detection (MEGA12, and Seqlogos), spacer identification (Actinobacteriophages db and BLAST), and bacteriophage detection (Phaster, and Phastest). Results: Cas proteins were detected in 36/77 species of the Leptospira genus, these proteins were (Cas1-Cas9, and Cas12). The proteins were classified into class 1 and class 2 systems, and types I, II, and V. Direct repeats and spacers were detected in 19 species. The direct repeats presented two nucleotide conservation motifs. With the spacer sequences, 270 different bacteriophages were identified. Three intact bacteriophages were detected in the genome of four Leptospira species. Two saprophytic species have complete CRISPR-Cas systems. Conclusions: The presence of Cas proteins, direct repeats, and spacer sequences homologous to bacteriophage genomes suggests a functional CRISPR-Cas system in at least 19 species.

Abstract: HTLV-1/2 coinfection in people with HIV (PWH) has been little studied in the Peruvian Amazon, an endemic area for both viruses. We aimed to estimate its prevalence and describe the main clinical and epidemiological features of co-infected individuals. We conducted a prospective, cross-sectional study (October–December 2023) at the Divi-sion of Infectious Diseases and Tropical Medicine from the Regional Hospital of Loreto, in Iquitos. We performed a screening test (recombinant HTLV I+II ELISA) and confirm the results with INNO-LIA. Among 293 PWH analyzed, 14 (4.1%) were HTLV positive: 1 was HTLV-1 (0.3%; 95% CI: 0.06-0.9), 11 were HTLV-2 (3.8%; 95% CI: 2.1-6.8) and 2 were non-typeable (0.7%; 95% CI: 0.1-2.7). Compared with HIV-monoinfected indi-viduals, coinfected patients were older (55 vs. 39 years; p=0.001) and more often had low education (35.7% vs. 15.4%; p=0.05). In conclusion, HIV–HTLV-2 coinfection is relatively common (~4%) in the Peruvian Amazon, particularly among older, ru-ral-born individuals, underscoring the need for targeted screening and prevention strategies in endemic areas.

Abstract: Kala-azar is associated with lethality rates of up to 10%, even with timely treatment. Early identification of mortality biomarkers can significantly reduce this risk. This study, strengthened by a relatively high number of kala-azar-related deaths, aimed to identify serum cytokines as predictive biomarkers of fatal kala-azar. We compared 48 deceased patients with kala-azar to 42 survivors. The concentrations of IL-1β, IL-6, IL-8, IL-10, IL-12, and tumor necrosis factor-α (TNF-α) were measured by flow cytometry. Cytokine levels, were compared between groups using the Wilcoxon rank-sum test. Receiver-operating-characteristic (ROC) analysis, coupled with Youden's index, defined the optimal diagnostic threshold. Upon admission, IL-8 concentrations were substantially higher in deceased kala-azar patients (median 76.5 pg/mL [IQR 35.2–242.4 pg/mL]) than in survivors (median 26.4 pg/mL [IQR 15.1–47.7 pg/mL]; p &lt; 0.0001). ROC analysis identified 49.3 pg/mL as the optimal cutoff. When rounded to the clinically convenient value of 50 pg/mL, IL-8 predicted a fatal outcome with an area under the curve of 0.75, sensitivity of 70.8%, and specificity of 76.2%. In contrast, IL-1β, IL-6, IL-10, IL-12, and TNF-α showed no significant prognostic utility. Our findings suggest that IL-8 levels equal to or greater than 50 pg/mL are a reliable predictor of fatal kala-azar.

Abstract: Background: Chikungunya virus (CHIKV) has historically been regarded as a low-fatality infection; however, growing evidence from diverse study designs demonstrates a substantial mortality burden during large-scale epidemics. In 2025, Réunion Island experienced a major CHIKV outbreak, raising renewed concerns about its fatal impact. Methods: We conducted an ecological time-series analysis of all-cause mortality in Réunion Island from March to May 2025, focusing on individuals aged ≥65 years. Excess deaths were estimated using a log-linear model adjusted for long-term trends and seasonality, with a baseline derived from the preceding five years. Observed deaths were compared to officially reported CHIKV fatalities and contextualized with data from previous epidemics worldwide. Results: An estimated 208 excess deaths occurred among older adults during the three-month epidemic, corresponding to a mortality rate ratio of 1.34 (95% CI: 1.22–1.47; p < 0.000001) in April 2025. Officially, only 27 deaths were attributed to CHIKV during this period (17 direct, 10 indirect), highlighting a substantial discrepancy between excess and reported mortality. Similar patterns have been repeatedly documented across different regions, including India (2006), the French Caribbean (2014), Puerto Rico (2014), Brazil (2015–2023), Jamaica (2014), and Mauritius (2006), where thousands of excess deaths far exceeded confirmed counts. Conclusions: Chikungunya epidemics are consistently associated with substantial underrecognized mortality worldwide. Routine surveillance relying solely on laboratory confirmation underestimates the true burden of disease. Integrating excess mortality analysis, strengthening diagnostic and postmortem investigations, and implementing timely mitigation measures are essential to accurately assess and reduce preventable deaths during future CHIKV outbreaks.

Abstract: The increasing incidence of Streptococcus suis (S. suis)-associated meningitis, which is significantly associated with sudden deafness, necessitates further investigation into its clinical characteristics and outcomes. To evaluate the clinical features and outcomes of S. suis-associated meningitis in a tertiary hospital in Bali, Indonesia, this cross-sectional study reviewed the medical records of patients diagnosed with suspected S. suis-associated meningitis from 2022 to 2024. The diagnosis of meningitis was based on the presence of fever, headache, neck stiffness, and altered mental status. Blood cultures were performed to confirm S. suis-associated meningitis. The diagnosis was confirmed when a blood culture was positive for S. suis and was probable based on a history of consuming raw pork. Both cases were categorized as S. suis-associated meningitis. Out of 67 patients, 34 (50.7%) presented with deafness. Common symptoms of meningitis include fever (100%), neck stiffness (100%), and severe headache (28.4%). Blood cultures revealed S. suis in 10.5% of cases. The total number of S. suis-associated meningitis cases was 31 out of 67 (46.3%), comprising probable cases (30, 44.8%) and confirmed cases (7, 10.4%). S. suis bacteremia caused deafness in 85.7% of cases. This study found no significant association between raw pork consumption and deafness (p = 0.151; odds ratio = 1.538, 95% CI = 0.584-4.055). The overall case fatality rate was 4.5%, with a 1.5% mortality rate among patients with confirmed S. suis-associated meningitis. The most common complications noted in this study were septic shock and sudden deafness. Increased awareness and preventive measures regarding pig-related exposure are crucial for managing this emerging public health threat.

Abstract: Human T-cell lymphotropic virus type 1 (HTLV-1) affects between 10 and 20 million people worldwide and remains a neglected infection in endemic areas such as southwestern Colombia. This study aimed to describe the clinical and demographic characteristics of forty-four patients with confirmed HTLV-1 infection treated at a referral center between January 2021 and December 2023. A retrospective case series analysis was conducted, including twenty-three pediatric patients, sixteen adults, and five pregnant women, with confirmation by Western Blot. Among the pediatric population, 52.2% presented with anemia, leukocytosis, and pulmonary coinfections, mainly due to Aspergillus spp. and Mycobacterium tuberculosis; 47.8% had infective dermatitis, and 45.5% had malnutrition. In adults, adult T-cell leukemia/lymphoma (ATLL) was the main manifestation (56.3%), followed by neurological involvement (43.7%). The mortality rate among adults was 68.7%, and one death was recorded in the pediatric group. The pregnant women had a mean age of 33 years and an average gestational age of 31.6 weeks at diagnosis; all were asymptomatic carriers. These findings highlight the clinical burden of HTLV-1 across different age groups and reinforce the need to implement public health strategies, including prenatal screening and comprehensive clinical follow-up in endemic areas.

Abstract: The case-fatality rate of severe leptospirosis can exceed 50%. This retrospective cohort study examined 111 individuals with laboratory-confirmed leptospirosis admitted to Cairns Hospital, a referral hospital in tropical Australia, between January 2015 and June 2024. We examined the patients’ demographic, clinical, laboratory and imaging findings at presentation and correlated them with disease course. Severe disease was defined as the presence of pulmonary haemorrhage or a requirement for intensive care unit (ICU) admission. The patients’ median (interquartile range) age was 38 (24-55) years; 85/111 (77%) were transferred from another health facility. Only 13/111 (12%) had any comorbidities. There were 63/111 (57%) with severe disease, including 56/111 (50%) requiring ICU admission. Overall, 56/111 (50%) required vasopressor support, 18/111 (16%) required renal replacement therapy, 14/111 (13%) required mechanical ventilation and 2/111 (2%) required extracorporeal membrane oxygenation. Older age – but not comorbidity – was associated with the presence of severe disease. Hypotension, respiratory involvement, renal involvement and myocardial injury – but not liver involvement – frequently heralded a requirement for ICU care. Every patient in the cohort survived to hospital discharge. Leptospirosis can cause multi-organ failure in otherwise well young people in tropical Australia; however, outcomes are usually excellent in the country’s well-resourced health system.

Abstract: Background: From 2018-2021, travel-related extensively drug-resistant (XDR) Salmonella Typhi was identified in Ontario, Canada. There remain opportunities to characterize typhoidal Salmonella antimicrobial susceptibility trends within a large health authority in British Columbia, Canada. Methods: This retrospective study included patients with Salmonella Typhi or Paratyphi A, B or C bacteremia identified at Fraser Health regional microbiology laboratory from 2018-2024. Primary outcome was proportion of cases with multi-drug resistant (MDR) and XDR typhoidal Salmonella. Secondary outcomes included annual antimicrobial susceptibility for ampicillin, ceftriaxone, ciprofloxacin, trimethoprim-sulfamethoxazole, ertapenem, meropenem and azithromycin. Clinical outcomes included hospitalization length, and 30-day mortality, clinical cure and infection relapse. Results: Among 271 patients, most were previously healthy and recently travelled. There were extended spectrum beta-lactamase (1.1%) and MDR (1.5%) typhoidal Salmonella, with no XDR cases observed. In 2024, ciprofloxacin resistance was 96% while susceptibility rates were high for other studied antimicrobials. Within 30 days, no deaths were reported; however, 6 patients (3%) had infection relapse. Conclusion: Currently in British Columbia, MDR typhoidal Salmonella remains rare. Empiric ciprofloxacin should be avoided due to persistently high resistance rates. With ongoing travel patterns, it is beneficial for institutions to continue typhoidal Salmonella antimicrobial susceptibility surveillance, and travelers should seek pre-travel health assessments.

Abstract:

Neurobrucellosis is a rare but serious complication of brucellosis, a zoonotic disease caused by bacteria of the genus Brucella. The most common clinical manifestations of neurobrucellosis include meningitis, encephalitis, and seizures. The diagnosis of neurobrucellosis should be considered when patients present with undulant fever, lethargy, seizures, or other features of meningitis/encephalitis. Occupational exposure to Brucella bacteria, particularly through contact with infected animals or their products, is a significant risk factor for developing neurobrucellosis. Certain occupations, such as farmers, veterinarians, and slaughterhouse workers, are at a higher risk of exposure. Recent research has suggested a potential link between neurobrucellosis and Parkinson's disease, although further investigation is needed to fully understand this association. Prevention and control of neurobrucellosis involve measures such as occupational hygiene, vaccination of livestock, and public education campaigns.

Abstract: Introduction: Leishmaniasis is a globally widespread zoonotic infection, including in the Mediterranean basin. There are four known types of disease: cutaneous, mucocutaneous, visceral and post Kala-Azar dermal leishmaniasis. Visceral Leishmaniasis (VL) is caused by Leishmania (L.) infantum and L. donovani. It manifests through general symptoms, hepatosplenomegaly and pancytopenia in children younger than ten years old and immunocompromised adults. Case presentation: An 18-year-old female patient is admitted for evaluation, in the context of prolonged febrile syndrome, after successive respiratory intercurrents, weight loss, night sweats and arthromyalgias, with the onset 8 months before. When interviewing the patient, one travel to Valencia, in October 2023, was reported. General laboratory analysis and abdominal ultrasound investigations showed no alterations. However, a specific Western blot test for anti-L. infantum IgG antibodies, was positive. Under treatment with amphotericin B, symptoms resolved and the following PCR test was negative. Conclusions: Leishmaniasis was identified in a female patient without specific risk factors. The finding underlines the need for a closer collaboration with infectious disease specialists, depending on the clinical and epidemiological context.

Abstract: The appearance of new clinical manifestations (for example subcutaneous or skin abscesses) during anti-tuberculosis treatment is generally indicative of therapeutic failure. The cause of therapeutic failure may be the presence of a drug-resistant Mycobacterium infection or to the failure to achieve a sufficient concentration of the drugs in the bloodstream. Here we report the case of a 25-year-old man suffering from tuberculosis infection with lymph nodes and pulmonary involvement and an atypical response to specific therapy. Two weeks after starting the 4-drug antitubercular treatment, the patient began to experience fever, pain and functional impotence in the left foot and ankle with subsequent evidence of ankle and tarsal osteomyelitis. Later on, four weeks after starting treatment, the patient presented with several widespread painful subcutaneous abscesses on the trunk, back and right lower limb. Drainage was performed from the ankle and from one of the abscesses and the polymerase chain reaction (PCR) showed positive result for Mycobacterium tuberculosis in both samples with absence of resistance to drugs. Anti-tubercular medications were continued with resolution of the pulmonary and bone involvement but with persistence of subcutaneous abscesses, although subsequent drainages showed the absence of mycobacterium tuberculosis. We describe an unusual presentation of paradoxical reaction in the form of osteomyelitis and subcutaneous abscesses in an immunocompetent TB patient and we reported other similar cases of paradoxical reactions described in the literature in the last ten years, which demonstrate the importance of considering paradoxical reactions in patients who present with new or worsening signs and symptoms after starting tuberculosis treatment.

Abstract:

Oropouche fever is caused by the Oropouche virus (OROV; Bunyaviridae, Orthobunyavirus), one of the most frequent arboviruses that infect humans in the Brazilian Amazon. This year, an OROV outbreak was identified in Brazil, and its vertical transmission was reported, which was associated with fetal death and microcephaly. We describe the clinical manifestations identified in three cases of congenital OROV infection with confirmed serology (OROV-IgM) in the mother-newborn binomial. One of the newborns died, and post-mortem molecular analysis using real-time RT-qPCR identified the OROV genome in several tissues. All three newborns were born in the Amazon region in Brazil, and the mothers reported fever, rash, headache, myalgia, and/or retroorbital pain during pregnancy. The newborns presented with severe microcephaly secondary to brain damage and arthrogryposis, suggestive of an embryo/fetal disruptive process at birth. Brain and spinal images identified overlapping sutures, cerebral atrophy, brain cysts, thinning of the spinal cord, corpus callosum, and posterior fossa abnormalities. Fundoscopic findings included macular chorioretinal scars, focal pigment mottling, and vascular attenuation. The clinical presentation of vertical OROV infection resembled congenital Zika syndrome to some extent but presents some distinctive features on brain imaging and in several aspects of its neurological presentation. A recognizable syndrome with severe brain damage, neurological alterations, arthrogryposis, and fundoscopic abnormalities can be associated with in-utero OROV infection.

Abstract: Background/Objectives: Many Tropical diseases such as Malaria, Chagas, Human African Trypanosomiasis, and Lymphatic filariasis coexist in endemic countries, affecting more than 1 billion people worldwide, and are recognized as major global vector-borne diseases. Tackle this disease lies in a correct diagnosis, sensitive, specific, and fast. This study aims to describe and validate a new highly sensitive and specific multiple-analysis system that can effectively detect numerous etiological agents in a single test. Methods: A total of 230 human blood samples were evaluated retrospectively for parasite characterization and a total of 58 stool samples from Non-Human Primates (NHP). Results: The analytical specificity of the presented method was 100%, with no unspecific amplifications or cross-reactions with other blood parasitic diseases. The detection limit obtained was between 0.6 to 3.01 parasites/µl for Plasmodium species, 1,8 parasite/ml for Trypanosomatidae, and 2 microfilariae/ml in the case of Filariae. The sensitivity, specificity, predictive values, and kappa coefficient reached almost 100%, except for the sensitivity for Filariae, which dropped to 93,9%, and its NPV to 89.5%. The operational features described a turnaround and a hands-on time notably shorter than the compared methods with a lower cost per essay. Conclusions: This work presents a cost-effective and highly sensitive multiplexed tool (RT-PCR-bp) capable of performing a simultaneous detection for blood parasitic diseases using specific fluorescence probes, enabling the diagnosis of low parasite loads and co-infections.

Abstract:

Background/Objectives: This study aimed to evaluate the prevalence of viral agents identified by multiplex PCR in ARVI patients at Edirne Sultan 1. Murat State Hospital from April 2023 to April 2024, and to investigate the relationship between monthly average humidity and viral pos-itivity rates. Methods: The study included 764 adult patients (aged 18 and older) diagnosed with influenza symptoms. Respiratory viral samples were collected and analyzed using Multiplex PCR for COVID-19, Influenza A and B, and RSV, with results evaluated retrospectively. Group variability was assessed using SPSS version 22, employing chi-square and t-tests, with a significance level of p < 0.05. A stepwise multivariate logistic regression analysis for COVID-19 was also conducted. Results: COVID-19 PCR positivity was detected in 142 patients (18.6%), with INF-A in 13 (3.7%), INF-B in 15 (4.2%), and RSV in 2 (0.6%). Higher humidity was associated with reduced viral PCR positivity rates for COVID-19 and Influenza B, while lower humidity correlated with peak cases (p<0.05 for both). Stepwise logistic regression analysis indicated that high humidity levels offer protection against COVID-19 (OR: 0.356; 95% CI: 0.245-0.518). Conclusions: Our study provides essential epidemiological data by summarizing monthly virus distribution in our region, facilitating effective vaccine selection.

Abstract: Considering the sustained increase of dengue outbreaks in Latin America in recent years, this study proposes the use of machine learning (ML) tools with epidemiological data, meteorological climate parameters considering El Niño and La Niña (Niño 3.4 Index), and socioeconomic and demographic phenomena as a basis for the construction of an early warning system for dengue outbreaks in Zulia State, Venezuela. The study area covers 21 municipalities. Two ML models, support vector regression machine (SVM-R) and Gaussian process regression (GPR), were used. The data were used raw, standardised, and normalized for each model to be trained. The predictions of dengue outbreaks from the GPR and SVR algorithms show agreement with the dates of the real data; it was determined that there is a range of 2 to 3 weeks depending on the municipality. These coincide with previous studies showing that the algorithms do not work properly for some municipalities.