Pathogens最新文献

Novel antigenic variant strains of the infectious bursal disease virus (IBDV) classified into genogroup A2d have been found in the western part of Japan since 2017. Novel antigenic variant IBDVs now occur in higher frequencies in poultry houses and have been detected in the eastern part of Japan, indicating the spread of IBDVs despite the usual IBDV vaccination. We isolated a novel antigenic variant IBDV, designated as the B2977CE2C3 strain. The B2977CE2C3 strain had two genogroup A2d specific amino acids-lysine and isoleucine, at 221 and 252 aa-along with the other genogroup A2 common amino acids in the projection domains of the VP2 protein corresponding to the virus-neutralizing epitopes and viral pathogenicity. Experimental infection of the B2977CE2C3 strain did not produce any apparent clinical signs in the specific-pathogen-free chickens during the observation period (21 days), but atrophy of the bursa of Fabricius (BF) was apparent. The mean BF to the body weight ratio was 0.35 in negative control chickens at 21 days post-infection (pi) but 0.06 in the B2977CE2C3 infected group. An extremely high copy number of the IBDV genome (>10⁸ copies/µL) was observed in the BF at 3 days pi, while a high copy number of the IBDV genome (>10⁶ copies/µL) was observed in the thymus, spleen cecal tonsil, and bone marrow even though macroscopic lesions were not apparent in these organs.

Background: The increased prevalence of antibiotic resistance among Gram-negative bacteria presents a severe public health challenge, leading to increased mortality rates, prolonged hospital stays, and higher medical costs. In Greece, the issue of multidrug-resistant Gram-negative bacteria is particularly alarming, exacerbated by overuse of antibiotics and inadequate infection control measures. This study aimed to detect the prevalence of extensively drug-resistant (XDR) Gram-negative bacteria in a tertiary hospital in Western Greece over the last eight years from 2016 to 2023. Materials and Methods: In the present study, all Carbapenem-resistant (CR) Acinetobacter baumannii, K. pneumoniae and Pseudomonas aeruginosa. bloodstream isolates from patients hospitalized in the University General Hospital of Patras in Western Greece, from January 2016 to December 2023, were recorded. XDR strains were defined as non-susceptible to at least one agent in all but two or fewer antimicrobial categories (i.e., bacterial isolates remain susceptible to only one or two categories). The prevalence and distribution of these pathogens across different hospital wards and their susceptibility patterns to key antibiotics (aminoglycosides, trimethoprim-sulfamethoxazole, tigecycline, colistin, ampicillin-sulbactam, ceftolozane-tazobactam and ceftazidime-avibactam) were recorded. Results: A total of 1142 blood cultures growing carbapenem-resistant Klebsiella pneumoniae (CRKp), Acinetobacter baumannii (CRAB) and Pseudomonas aeruginosa (CRPsA) were studied. In the present study, we found an increased resistance of both A. baumannii and K. pneumoniae in colistin. Acinetobacter baumannii had colistin resistance rates between 8.4% and 49.3%, showing a stable increase during the study period. K. pneumoniae showed an increased colistin-resistance rate in 2022 and 2023 (46.8% and 31.2%, respectively) Regarding P. aeruginosa, amikacin was almost inactive with a rate 68.4% and 87.5% in 2020 and 2023, respectively. Of all CR isolates, 69.3% were extensively drug-resistant (XDR). Acinetobacter baumannii had the highest percentage of XDR isolates (34.3%), followed by K. pneumoniae (26.8%) and P. aeruginosa (8.1%). Most XDR pathogens were isolated from the ICU (73.4%), followed by the internal medicine units (64%) and surgical units (22%). Conclusions: The rate of antimicrobial resistance and extensive drug resistance is alarmingly high, which calls for strict surveillance, control measures, and antibiotic stewardship to prevent the development of further resistance.

Natural killer (NK) and CD8⁺ T cell function is compromised in human immunodeficiency virus type 1 (HIV-1) infection by increased expression of inhibitory receptors such as TIGIT (T cell immunoreceptor with Ig and ITIM domains). Blocking inhibitory receptors or their ligands with monoclonal antibodies (mAb) has potential to improve antiviral immunity in general and facilitate HIV eradication strategies. We assessed the impact of TIGIT engagement and blockade on cytotoxicity, degranulation, and interferon-gamma (IFN-γ) production by CD8⁺ T cells from persons living with HIV (PLWH). The effect of TIGIT engagement on non-specific anti-CD3-redirected cytotoxicity was assessed in redirected cytotoxicity assays, and the effect of TIGIT blockade on HIV-specific CD8⁺ T cell responses was assessed by flow cytometry. In 14/19 cases where peripheral blood mononuclear cells (PBMC) mediated >10% redirected cytotoxicity, TIGIT engagement reduced the level of cytotoxicity to <90% of control values. We selected PLWH with >1000 HIV Gag or Nef-specific IFN-γ spot forming cells per million PBMC to quantify the effects of TIGIT blockade on HIV-specific CD8⁺ T cell responses by flow cytometry. Cell surface TIGIT expression decreased on CD8⁺ T cells from 23/40 PLWH following TIGIT blockade and this loss was associated with increased anti-TIGIT mAb fluorescence on monocytes. In total, 6 of these 23 PLWH had enhanced HIV-specific CD8⁺ T cell degranulation and IFN-γ production with TIGIT blockade, compared to 0/17 with no decrease in cell surface TIGIT expression. Reduced CD8⁺ T cell TIGIT expression with TIGIT blockade involved trogocytosis by circulating monocytes, suggesting that an effector monocyte population and intact fragment crystallizable (Fc) functions are required for mAb-based TIGIT blockade to effectively enhance HIV-specific CD8⁺ T cell responses.

Herpes simplex virus (HSV) in humans and pseudorabies virus (PRV) in pigs are both alphaherpesviruses. Plasmacytoid dendritic cells (pDCs) make part of the peripheral blood mononuclear cells (PBMCs) and are specialized in producing large amounts of antiviral type I interferon (IFN-I). IFN-I production by PBMCs in response to both HSV-1 and PRV can be virtually exclusively attributed to pDCs. Recently, we discovered that cells infected with gEnull PRV trigger increased production of IFNalpha by porcine PBMCs/pDCs compared with cells infected with wild-type (WT) PRV. This increased IFNalpha response correlates with increased extracellular virus production triggered by gEnull PRV compared with WT PRV. The gE protein and some of its currently described functions are conserved in different alphaherpesviruses, including PRV and HSV-1. In the current study, we report that cells infected with gEnull HSV-1 trigger increased IFNalpha production by human PBMCs and increased extracellular virus production compared with WT HSV-1. Hence, these recently described functions of PRV gE are conserved in HSV-1 gE. Since the increased extracellular virus production and IFNalpha response have also been reported for successful (gEnull) PRV vaccines, the current findings may have important consequences for the rational design of HSV vaccines.

Malaria remains a major public health threat in Sub-Saharan Africa. According to the World Health Organization (WHO) estimates, Plasmodium falciparum species account for nearly 100% of the malaria cases occurring on the African continent. According to the Centers for Disease Control and Prevention (CDC), falciparum malaria predominates, but non-falciparum species are also present in Africa. The aim of the study was to assess the occurrence of asymptomatic malaria cases, as well as to identify Plasmodium species at two different settings with the lowest index of infections in Tanzania (according to the Tanzanian Ministry of Health < 1%), i.e., on the mainland (Arusha Region) and on the Pemba Island (Zanzibar Archipelago). The study was conducted in June 2023 and involved 722 individuals, including 449 residents of mainland Tanzania and 273 residents of the Zanzibar Archipelago. The screening consisted of two phases. In the first one, which was carried out at two different settings, i.e., in the Karatu Lutheran Hospital (Arusha Region, mainland Tanzania) and the Amal Hospital (Pemba, Zanzibar Archipelago), mRDTs (malaria rapid diagnostic tests) were performed, haemoglobin concentrations were measured, and blood samples for further molecular tests were collected onto Whatman micro cards from each of the individuals involved. In the second phase (conducted in Poland, Europe), RT-PCR tests for malaria were performed. The screening found asymptomatic Plasmodium infections in 4.2% of the study subjects from mainland Tanzania and in 4.8% from the Archipelago. The research confirmed cases of P. falciparum malaria but also found single cases of mixed infections with P. falciparum + P. malariae or P. ovale. The results demonstrated that the occurrence of malaria in northern mainland and Zanzibar Archipelago is higher than the official MoH reports present. The study findings are consistent with the reports by CDC, which suggest that non-falciparum species are also present in Sub-Saharan Africa.

Various Salmonella serotypes have caused numerous foodborne outbreaks associated with food vehicles in different categories. This study provides evidence on the occurrence and inter-relations between Salmonella serotypes and the number of deaths mediated by the number of illnesses and hospitalizations. Confirmed foodborne outbreaks of Salmonella serotypes (n = 2868) that occurred between 1998 and 2021 were obtained from the Centers for Disease Control and Prevention National Outbreak Reporting System. Causal mediation analysis was performed based on 500 bootstrap samples. The serotypes and the Interagency Food Safety Analytics Collaboration (IFSAC) food categories as confounding effects were considered as categorical variables. A total of 106 single Salmonella serotypes were associated with foodborne outbreaks. Foodborne outbreaks caused by Salmonella serotypes resulted in 81,996 illnesses, 11,018 hospitalizations, and 115 deaths between 1998 and 2021 in the United States. The serotypes Enteritidis (815 outbreaks, 28.42%), Typhimurium (359 outbreaks, 12.52%), and Newport (220 outbreaks, 7.67%) accounted for almost half of Salmonella-linked outbreaks. Poultry products, "chickens", "eggs", and "turkey", were the leading IFSAC food categories, accounting for 14.02% of total outbreaks and 10.44% of total deaths. Certain serotypes had a significant effect on illness, hospitalization, and death counts. Two serotypes, Heidelberg and Saintpaul, and "fruits" as the food vehicle in IFSAC categories had a significant direct effect on the number of illnesses, hospitalizations, and deaths as outcomes of Salmonella outbreaks (p ≤ 0.05). There was strong evidence that illness and hospitalization counts played a key role in the pathway from serotype to death counts on foodborne outbreaks caused by Salmonella based on causal mediation analysis. The findings of this study can help outbreak investigations and lead to prevention and control measures by providing insightful information about the frequencies of Salmonella serotypes and the associated food vehicles causing foodborne diseases.

Orthorubulavirus suis (LPMV) is the etiologic agent of blue eye disease (BED), which affects pigs of all ages, and it has been endemic in central Mexico since the 1980s. To date, no disease control program has been established. Therefore, there is a need for a serological diagnostic method with high sensitivity and specificity. In this study, the recombinant protein NP of LPMV was produced in the E. coli BL21 system and then purified using affinity chromatography. The purified protein was used to coat plates for an indirect ELISA assay (iELISA). To determine the sensitivity and specificity of the test, a 2 × 2 contingency table was constructed using positive and negative control sera. The specificity and sensitivity levels were 98.1% and 98.7%, respectively. According to our findings, 45% of serum samples (378/839) were positive, with seropositivity percentages in the analyzed states ranging from 72.5% to 6%. To confirm the presence of antibodies, the indirect immunofluorescence technique was applied to iELISA-positive serum samples. In this study, antibodies against the LPMV nucleoprotein were detected, indicating that the virus or defective particles may be circulating in Mexican pigs and highlighting the risk of LPMV spreading to disease-free areas.

Tick-borne diseases (TBDs) pose a growing threat to companion animals, especially dogs, due to the increasing abundance of tick populations in Europe, driven by climate change, urbanization, and the mobility of humans and animals. This study aimed to assess the prevalence of tick-borne pathogens in clinically ill dogs suspected of having developed TBDs during the autumn-winter season, as well as to detect pathogens in ticks collected during the same period in the Warmian-Masurian Voivodeship in Poland. A total of 30 dogs with clinical symptoms of babesiosis and 45 ticks from dogs were acquired for this study. Clinical symptoms in dogs included elevated body temperature > 39.0 °C (73.3%), anemia (56.7%), thrombocytopenia (80%), and dark urine (53.3%). Co-infections with Babesia spp. were identified in two combinations (Babesia spp. and Mycoplasma spp. (n = 5), Babesia spp. and Borrelia spp. (n = 2)) and one co-infection with Anaplasma spp. and Borrelia spp., highlighting the complexity of TBD diagnosis and treatment. The analyzed tick species were Ixodes ricinus (86.7%; n = 39; 18 females and 21 males) and Dermacentor reticulatus (13.3%; n = 6; 4 females and 2 males). In I. ricinus, Babesia spp. were identified in 7.7% (3/39), Mycoplasma spp. in 7.7% (3/39), Borrelia in 25.6% (10/39), and Anaplasma spp. in 10.3% (4/39). In D.reticulatus, only two pathogens-Borrelia spp. and Anaplasma spp.-were detected, both only once (16.7%; 1/6). No significant differences were observed between the prevalence of the studied pathogens and tick species, sex, or developmental stage. This study emphasizes the year-round risk of TBDs in dogs, particularly during the autumn-winter months, and underscores the need for continuous vigilance in tick prevention, broad-spectrum diagnostics, and treatment strategies.

The West Nile virus (WNV) has recently become more widespread, posing a threat to both human and animal health. In Western Europe, most outbreaks have been caused by WNV lineage 1, while in Eastern Europe, WNV lineage 2 has led to human and bird mortality. The ability to appropriately manage this threat is dependent on integrated surveillance and early detection. This study aimed to quantify the prevalence of WNV infection in mosquitoes and to identify the circulating viral lineage in eastern Croatia. Mosquito traps were set up in rural and urban areas during the 2021-2023 seasons, and the collected specimens were identified morphologically. Mosquito species Culex pipiens and Aedes albopictus were tested for Flaviviruses using conventional PCR in a heminested system. The positive samples were then subjected to a specific real-time PCR designed to detect WNV. A total of 385 mosquito pools were tested, and positive pools were found in samples from Osijek-Baranja and Vukovar-Srijem, both of which contained Cx. pipiens mosquitoes. Sequencing of amplicons revealed WNV lineage 2 partial NS5 gene sequences. Phylogenetic analysis suggests the Hungarian origin of strain, which complements birds' migratory routes. These findings indicate the first detection of WNV in mosquitoes in Croatia. This suggests that human cases in this region are likely due to infections with lineage 2 transmitted by local Culex mosquitoes.

Disease monitoring informs the opportunities for intervention by natural resource agencies tasked with managing chronic wasting disease (CWD) in wild cervids. However, allocating funds toward testing can reduce those available for education, outreach, and disease reduction. Implementation of more efficient testing strategies can help meet both an expanding need by resource managers and a burgeoning demand from the hunting public in North America. Here, we evaluated the efficacy of pooled testing using the enzyme-linked immunosorbent assay (ELISA), the current screening test used by veterinary diagnostic laboratories in the United States, and real-time quaking-induced conversion (RT-QuIC), an amplification assay that is being evaluated by the U.S. Department of Agriculture but is not yet approved or commercially available. The samples used in this study consisted of medial retropharyngeal lymph nodes (RPLNs) routinely collected by the Iowa Department of Natural Resources during the 2019-2020 surveillance season. The test pools contained tissue from one positive deer diluted in tissue from an increasing number of undetected deer, with each individual contributing an equal tissue volume. ELISA remained positive with pooling thresholds of 1:1, 1:2, 1:4, and 1:9 at a standard volume of tissue homogenate, whereas RT-QuIC remained positive with pooling thresholds of 1:1, 1:2, 1:4, 1:9, 1:19, and 1:49 at a 0.02% tissue dilution. Our results suggest that pooled testing can reduce diagnostic costs multi-fold, and RT-QuIC can be a viable screening test compatible with current field collection standards.