Natural Infection Research Articles

The Natural Infection of Freshwater Snails with the Avian Air Sac Fluke, Cyclocoelum mutabile (Trematoda: Cyclocoelidae), in Brazil

Trematodes of the family Cyclocoelidae are parasites mainly of the respiratory system of birds and present a cosmopolitan distribution. Although infection with these flukes can result in pathological changes and even bird death, information on their life cycles is scarce and almost entirely based on experimental infection data. Thus, the generation of knowledge on the mollusks that act as natural intermediate hosts of cyclocoelids is necessary and can aid control measures against these air sac trematodes. In the present study, gastropod mollusks collected in an urban stream from Belo Horizonte, Minas Gerais, Brazil, were subjected to the compression technique for the detection of non-emerging larval trematodes. Tailless cercariae with confluent ceca were found in 8/30 (26.7%) specimens of Biomphalaria glabrata and 3/33 (9.1%) specimen of Physella acuta. Samples of the cercariae were subjected to morphological characterization and genetic study (28S, Cox-1, and Nad-1). For comparative purposes, adult trematodes previously collected in the air sac of a common gallinule (Gallinula galeata) found dead in another waterbody from the same region were also characterized. The molecular sequences obtained revealed a high degree of similarity (100% in 28S, 99.2% in Cox-1, and 99.5% in Nad-1) between larval stages found in mollusks and adult parasites found in G. galeata and morphologically identified as Cyclocoelum mutabile. The conspecificity with this widely distributed cyclocoelid was also corroborated by phylogenetic analysis and comparison with isolates of this species previously characterized in Peru and the Czech Republic (99.4–100% and 96.7–97.0% of similarity in Nad-1, respectively). Thus, the integrative analysis carried out in the present work enabled us to identify C. mutabile in mollusks in South America for the first time. The finding of B. glabrata and P. acuta as new intermediate hosts corroborates the importance of freshwater gastropods in the transmission of C. mutabile, as well as the low specificity to the mollusk group, as previously characterized through experimental studies.

Factors Influencing Breast Milk Antibody Titers during the Coronavirus Disease 2019 Pandemic: An Observational Study.

The COVID-19 pandemic has highlighted the role of breastfeeding in providing passive immunity to infants via specific anti-SARS-CoV-2 antibodies in breast milk. We aimed to quantify these antibodies across different lactation stages and identify influencing factors. This prospective study involved mother-child dyads from Innsbruck University Hospital, Austria, with a positive maternal SARS-CoV-2 test during pregnancy or peripartum between 2020 and 2023. We collected breast milk samples at various lactation stages and analyzed anti-Spike S1 receptor-binding domain (S1RBD) immunoglobulins (Ig). Maternal and neonatal data were obtained from interviews and medical records. This study included 140 mothers and 144 neonates. Anti-S1RBD-IgA (72.0%), -IgG (86.0%), and -IgM (41.7%) were highly present in colostrum and decreased as milk matured. Mothers with natural infection and vaccination exhibited higher anti-S1RBD-IgA and -IgG titers in all milk stages. Mothers with moderate to severe infections had higher concentrations of anti-S1RBD-IgA and -IgG in transitional milk and higher anti-S1RBD-IgA and -IgM in mature milk compared to those with mild or asymptomatic infections. Variations in antibody responses were also observed with preterm birth and across different virus waves. This study demonstrates the dynamic nature of breast milk Ig and underscores the importance of breastfeeding during a pandemic.

Establishment of an A/T-Rich Specifically MGB Probe digital droplet PCR Assays Based on SNP for Brucella wild strains and vaccine strains

In recent years, immunization with the S2 live-attenuated vaccine has been recognized as the most economical and effective strategy for preventing brucellosis in Inner Mongolia, China. However, there are still challenges related to vaccine toxicity and the inability to distinguish between vaccine immunization and natural infection. Therefore, in this study, we developed a digital droplet polymerase chain reaction (ddPCR) assay based on single-nucleotide polymorphism (SNP) loci to identify wild Brucella strains and S2 vaccine strains. The assay demonstrated excellent linearity (R2> 0.99) with a lower detection limit of 10 copies/µL for both wild and vaccine strains. Additionally, the ddPCR assay outperformed the real-time fluorescent quantitative PCR (qPCR) assay in screening 50 clinical samples. We have established an effective and highly sensitive ddPCR assay for Brucella, providing an efficient method for detecting and differentiating wild strains of Brucella from the S2 vaccine strain.

Controlled human hookworm infection remodels plasmacytoid dendritic cells and regulatory T cells towards profiles seen in natural infections in endemic areas

Hookworm infection remains a significant public health concern, particularly in low- and middle-income countries, where mass drug administration has not stopped reinfection. Developing a vaccine is crucial to complement current control measures, which necessitates a thorough understanding of host immune responses. By leveraging controlled human infection models and high-dimensional immunophenotyping, here we investigated the immune remodeling following infection with 50 Necator americanus L3 hookworm larvae in four naïve volunteers over two years of follow-up and compared the profiles with naturally infected populations in endemic areas. Increased plasmacytoid dendritic cell frequency and diminished responsiveness to Toll-like receptor 7/8 ligand were observed in both controlled and natural infection settings. Despite the increased CD45RA+ regulatory T cell (Tregs) frequencies in both settings, markers of Tregs function, including inducible T-cell costimulatory (ICOS), tumor necrosis factor receptor 2 (TNFR2), and latency-associated peptide (LAP), as well as in vitro Tregs suppressive capacity were higher in natural infections. Taken together, this study provides unique insights into the immunological trajectories following a first-in-life hookworm infection compared to natural infections.

Chronological Management of Adjuvant Effect for Optimized mRNA Vaccine Inspired by Natural Virus Infection.

The efficacy and safety of mRNA vaccines both rely on a fine-tuning of specific humoral and cellular immune responses. Instead of adjustments in vaccine component, we proposed a concept of chronological management of adjuvant effect to modulate the adaptive immune potency and preference inspired by natural virus infection. By simulating type I interferon expression dynamics during viral infection, three vaccine strategies employing distinct exposure sequences of adjuvant and mRNA have been developed, namely Precede, Coincide, and Follow. Follow, the strategy of adjuvant administration following mRNA, effectively suppressed tumor progression, which was attributed to enhanced mRNA translation, augmented p-MHC I expression, and elevated CD8+ T cell response. Meanwhile, Follow exhibited improved biosafety, characterized by reduced incidences of cardiac and liver toxicity, owing to its alteration to the vaccination microenvironment between successive injections. Our strategy highlights the importance of fine-tuning adjuvant effect dynamics in optimizing mRNA vaccines for clinical application.

Longer interval between maternal RSV vaccination and birth increases placental transfer efficiency.

Respiratory Syncytial Virus (RSV) is associated with significant neonatal and infant morbidity and mortality. Maternal bivalent RSVpreF RSV vaccination to protect neonates and infants was approved in September 2023 for administration between 32+0 and 36+6 weeks to protect neonates and infants. This approved timeframe is narrower than the 24-36 week window evaluated in the clinical trial, due to the possible association between preterm birth and vaccine administration. Currently, data are lacking on how maternal vaccine timing within the approved window affects the transfer of antibodies from mother to fetus, critical information that could influence clinical practice. We sought to examine how gestational age at vaccination and time elapsed from maternal RSV vaccination to delivery impacted transfer of maternal antibodies measured in the umbilical cord at delivery and in peripheral blood of 2-month infants. We also examined differences in maternal and cord RSV antibody levels achieved by vaccination versus natural RSV infection. A prospective cohort study was conducted at two academic medical centers between September 20, 2023 and March 21, 2024, enrolling 124 individuals who received the RSV vaccine during pregnancy. Infant capillary blood was collected at 2 months of age from 29 of the infants. Maternal and cord IgG levels achieved by RSV vaccination were compared to those associated with maternal natural RSV infection, using banked blood from 20 maternal:cord dyads collected prior to the availability of the maternal RSV vaccine. Levels of IgG against RSV strain A2 and B fusion (F) and attachment (G) proteins and against pertussis toxin (as a comparator antigen from a vaccine routinely administered earlier in pregnancy) were measured using a Binding Antibody Multiplex Assay. Differences in titers between vaccination and natural infection were examined using Wilcoxon rank sum test. Differences in cord:maternal transfer ratios and 2-month infant antibody levels by timing of maternal vaccination were evaluated by Kruskal-Wallis testing. Maternal RSV vaccination resulted in significantly higher maternal and cord anti-F RSV antibody levels than natural infection (5.72 vs 4.82 log 10 MFI, p < 0.0001 maternal; 5.81 vs 5.03 log 10 MFI, p < 0.0001 cord). Maternal vaccination 2-3 weeks and 3-4 weeks prior to delivery was associated with significantly lower cord:maternal transfer ratios than were observed when vaccination occurred > 5 weeks prior to delivery (p = 0.03 for 2-3 weeks, p = 0.007 for 3-4 weeks), and significantly lower transfer ratios than observed for pertussis vaccination administered prior to 30 weeks' gestation (p = 0.008 for 2-3 weeks, p = 0.03 for 3-4 weeks, similar at > 4 weeks). Vaccine administration earlier in the approved 32-36 week window (at least 5 weeks prior to delivery) results in the highest transplacental transfer of maternal antibodies to the neonate. These results should inform the counseling of pregnant individuals on optimal vaccination timing.

Comparative evaluation of disease dynamics in wild boar and domestic pigs experimentally inoculated intranasally with the European highly virulent African swine fever virus genotype II strain “Armenia 2007”

Since the reintroduction of African swine fever virus (ASFV) in Europe in 2007 and its subsequent spread to Asia, wild boar has played a crucial role in maintaining and disseminating the virus. There are significant gaps in the knowledge regarding infection dynamics and disease pathogenesis in domestic pigs and wild boar, particularly at the early infection stage. We aimed to compare domestic pigs and wild boar infected intranasally to mimic natural infection with one of the original highly virulent genotype II ASFV isolates (Armenia 2007). The study involved euthanising three domestic pigs and three wild boar on days 1, 2, 3, and 5 post-infection, while four domestic pigs and four wild boar were monitored until they reached a humane endpoint. The parameters assessed included clinical signs, macroscopic lesions, viremia levels, tissue viral load, and virus shedding in nasal and rectal swabs from day 1 post-infection. Compared with domestic pigs, wild boar were more susceptible to ASFV, with a shorter incubation period and earlier onset of clinical signs. While wild boar reached a humane endpoint earlier than domestic pigs did, the macroscopic lesions were comparatively less severe. In addition, wild boar had earlier viremia, and the virus was also detected earlier in tissues. The medial retropharyngeal lymph nodes were identified as key portals for ASFV infection in both subspecies. No viral genome was detected in nasal or rectal swabs until shortly before reaching the humane endpoint in both domestic pigs and wild boar, suggesting limited virus shedding in acute infections.

Multiplex Assay to Determine Acute Phase Proteins in Modified Live PRRSV Vaccinated Pigs.

Acute phase protein (APP) response to vaccine challenges is an attractive alternative to natural infection for identifying pigs with increased disease resilience and monitoring the productive performance. Currently, the methods used for APP quantification are diverse and often based on techniques that use antibodies that are not necessarily pig specific. The objective of this work is the development of a method based on a UPLC-SRM/MS system for simultaneous determination of haptoglobin, apolipoprotein A1, C-reactive protein, pig-major acute protein, and serum amyloid A and its application in pigs to monitor the effect of a vaccine administered against porcine reproductive and respiratory syndrome virus (PRRSV). With the aim of tracing the complete analytical process for each proteotypic peptide, a synthetic QconCat polypeptide construct was designed. It was possible to develop an SRM method including haptoglobin, apolipoprotein A1, pig-MAP, and serum amyloid A1. The PRRSV vaccine only affected haptoglobin. The pigs with positive viremia tended to show higher values than negative pigs, reaching significant differences in the three haptoglobin SRM-detected peptides but not with the data acquired by immunoenzymatic and spectrophotometric assays. These results open the door to the use of SRM to accurately monitor APP changes in experimental pigs.

Temporal Dynamics of Purinergic Receptor Expression in the Lungs of Marek's Disease (MD) Virus-Infected Chickens Resistant or Susceptible to MD.

Marek's disease virus (MDV) is an economic concern for the poultry industry due to its poorly understood pathophysiology. Purinergic receptors (PRs) are potential therapeutic targets for viral infections, including herpesviruses, prompting our investigation into their role in MDV pathogenesis. The current study is part of an experimental series analyzing the expression of PRs during MDV infection. To address the early or short-acting P2 PR responses during natural MDV infection, we performed an "exposure" experiment where age-matched chickens were exposed to experimentally infected shedders to initiate natural infection. In addition, select non-PR regulatory gene responses were measured. Two groups of naïve contact chickens (n = 5/breed/time point) from MD-resistant (White Leghorns: WL) and -susceptible (Pure Columbian) chicken lines were housed separately with experimentally infected PC (×PC) and WL (×WL) chickens for 6 or 24 h. Whole lung lavage cells (WLLC) were collected, RNA was extracted, and RT-qPCR assays were used to measure specific PR responses. In addition, other potentially important markers in pathophysiology were measured. Our study revealed that WL chickens exhibited higher P1 PR expression during natural infection. WL chickens also showed higher expression of P1A3 and P2X3 at 6 and 24 h when exposed to PC-infected chickens. P2X5 and P2Y1 showed higher expression at 6 h, while P2Y5 showed higher expression at 6 and 24 h; regardless of the chicken line, PC chickens exhibited higher expression of P2X2, P2Y8, P2Y10, P2Y13, and P2Y14 when exposed to either group of infected chickens. In addition, MDV infection altered the expression of DDX5 in both WL and PC groups exposed to PC-infected birds only. However, irrespective of the source of exposure, BCL2 and ANGPTL4 showed higher expression in both WL and PC. The expression of STAT1A and STAT5A was influenced by time and breed, with major changes observed in STAT5A. CAT and SOD1 expression significantly increased in both WL and PC birds, regardless of the source of infection. GPX1 and GPX2 expression also increased in both WL and PC, although overall lower expression was observed in PC chickens at 24 h compared to 6 h. Our data suggest systemic changes in the host during early infection, indicated by the altered expression of PRs, DDX5, BCL2, ANGPTL4, and other regulatory genes during early MDV infection. The relative expression of these responses in PC and WL chickens suggests they may play a key role in their response to natural MDV infection in the lungs and long-term pathogenesis and survival.

Postexposure Pestes-des-petits-ruminants vaccination with oxytetracycline therapy mitigates severe disease and increases survivability in natural infections

Postexposure Pestes-des-petits-ruminants vaccination with oxytetracycline therapy mitigates severe disease and increases survivability in natural infections

First Report of Diaporthe tectonendophytica Causing Leaf Spot on Dalbergia odorifera in Guangxi, China.

Dalbergia odorifera T. Chen (Family: Fabaceae) is a national level II protected plant in China, with extremely high economic value and medical properties (Zhao et al. 2020). In June 2023, an unknown leaf spot was found in a garden land of Pingxiang city, Guangxi, China, and approximately 80% of the plants covered an area of 500 m2 displayed similar symptoms. The spots were grey to white, 4~6 mm in diameter (n=30) with black pycnida on the spots surface (Fig S1, A-D). Multiple disease spots were observed on a single leaf. The pycnida on the lesion were picked and mashed, to make a conidia suspension using sterile water. The conidial solution was then spread onto a potato dextrose agar (PDA) plate containing streptomycin, with 10 mg of streptomycin per 100 mL, and incubated for 3 days at 28°C with a 12 hour photoperiod. Three isolates (GXPX01, GXPX02 and GXPX03) were obtained by re-culturing the colonies on fresh PDA plates. The colony on PDA were white with aerial mycelia (Fig S1, E-F). Black conidiomata developed at 28°C with a 12 hour photoperiod in 20 days (Fig S1, G-H). Alpha conidia were 4.2~6.4 μm × 1.8~2.6 μm (average =5.1 × 2.3 μm, n = 30), mostly bi-guttulate, hyaline, ellipsoid, apex bluntly rounded, base obtuse to subtruncate, smooth (Fig S1, I). Beta conidia were 15.1~33.5 μm × 1~1.8 μm (average = 24.5 × 1.5 μm, n = 30), filiform, hyaline, curved or hamate, aseptate, base subtruncate (Fig S1, J). Morphological characteristics of the three isolates matched those of Diaporthe spp.(Gomes et al. 2013). The rDNA internal transcribed spacer (ITS) region, the translation elongation factor 1-α (TEF1), the calmodulin (CAL), the histone H3 (HIS) and the β-tubulin (TUB2) genes of the three isolates were amplified using the primer pairs ITS4/ITS5, EF1-728F/EF1-986R, CAL-228F/CAL2Rd, CYLH3F/H3-1B, and T1 /CYLTUB1R, respectively (Crous et al. 2004, Sun et al. 2021). The sequences were all deposited in GenBank (accession numbers OR437511 to OR437513 for ITS, OR454965 to OR454967 for TEF1, OR454968 to OR454970 for CAL, OR454971 to OR454973 for TUB2, OR454974 to OR454976 for H3). Sequences had 98.36% to 100% homology with the corresponding sequences of known Diaporthe tectonendophytica strains MFLUCC 13-0471 in the NCBI database. Phylogenetic analysis was based on combined ITS, TEF1, TUB2 and CAL sequences data using MEGA 11 software to construct phylogenetic tree with Maximum Likelihood (Doilom et al. 2017). In the phylogenetic tree, the combined sequences attributed the three isolates to the D. tectonendophytica (Fig S2). The pathogenicity was tested on leaves of 1.5-year-old D. odorifera seedlings. Three leaves were wounded with a sterile needle and individually inoculated with a 5 mm mycelial disk of PDA culture from each isolate. Sterile PDA disks inoculated leaves as a control. The test was repeated three times. The inoculated plants were placed in a greenhouse at 25℃ and 90% humidity, with a photoperiod of 12 hours. Five days after inoculation, necrotic lesions appeared on inoculated leaves and symptoms from all three isolates were the same as those form natural infections ( Fig S1, K-N), whereas all the control remained symptomless (Fig S1, P). The pathogen was reisolated from the inoculated leaves and again identified as D. tectonendophytica, with the same methodology used for the initial identification. D. tectonendophytica was reported to cause plant diseases, such as stem gray blight of red-fleshed dragon fruit (Hylocereus polyrhizus) (Rahim et al. 2021), leaf spots disease on Elaeagnus conferta and Pometia pinnata (Sun et al. 2021). To our knowledge, this is the first report of D. ctonendophytica causing leaf spot disease on D. odorifera.

The biological characteristics of DAstV molecular epidemiology and pathogenicity of duck astrovirus causing hepatitis in ducks and chickens in Southeast China

A suspected outbreak of duck astrovirus (DAstV) disease occurred in a large Muscovy duck farm in Guangdong Province, China, in June 2022, which severely affected the production performance and health of Muscovy ducks. This study aimed to investigate the prevalence of DAstV disease in Southeast China. Herein, we employed semi-nested PCR ethodto screen 5203 swab and liver samples from 11 Muscovy duck farms in 5 provinces of China for the presence of DAstV. Among them, 1356 samples (26.06%, 1356/5203) tested positive for DAstV, out of which 11 DAstV strains were isolated after 10 generations of blind transmission through Leghorn male hepatoma (LMH) cells and performed their whole-genome sequencing. The alignment results showed that the 11 DAstV isolates exhibited relatively low homology (15.4%-75%) with the astrovirus isolates from other species published in GenBank, whereas their homology (nucleotide: 90.4%-99.99%; amino acid: 94%-99.8%) with the DAstV type 1 (DAstV-1) reference strain was higher, indicating considerable homology. The results indicated that DAstV-1 was the main pathogenic factor. Herein, we successfully recreated the clinical symptoms of natural infection in 28-day-old specific-pathogen-free (SPF) ducks using the DAstV-1-GDB-2022 strain. The primary clinical manifestations included liver enlargement, hemorrhaging, and disruptions in liver function. Additionally, we confirmed the cross-species transmission potential of DAstV-1, marking the first occurrence of clinical symptoms of DAstV in 28-day-old SPF chickens. Our findings provide new perspectives on the epidemiology and pathogenicity of DAstV-1 and may help in advancing the development of DAstV vaccines.

Study about environmental naturally fungi infection in pet animals with experimental study

The current study was designed to investigate Environmental and natural fungi infection in pet animals and then experimentally to study fungi effects on tissues. Naturally infectious samples were fifty swabs in different pet animals (dogs, cats, rats, pigeons, and chickens) from the veterinary hospital of Eden Square in January 202. The findings were Cladosporum spp at (16%) ; Aspergillus flavus, Aspergillus niger at (14%); Rhizopus spp at (8%); Aspergillus ochraceus, Aspergillus terreus, and Penicillium chrysogenum at (6%); Chrysosporium spp, and Cryptococcus neoformans at (4%); Aspergillus fumigatus , Aspergillus ustus and Fusarium spp at (2%) in percentage with other unknown fungi. In doge, only 9 (9/50) samples of fungi, mainly Aspergillus flavus at (33.3%) with cladogram spp.at (22.3%). In cats, also 9 (9/50), mainly Penicillium spp at (22.25 %). In wild rats, fifty cotton swabs showed 12 (12/50) mainly Aspergillus niger, besides Rhizopus spp. At (25%). While in pigeons, only 10 (10/50), mainly Aspergillus niger, Cladosporum spp., and Cryptococcus neoformans at (20%). In chicken, only 5 (5/50), mainly Aspergillus ochraceus at (40%). Fifty albino mice aged 6-8 weeks and 25± 3gm body weight. They were separated in plastic cages and kept for adaptation at 2-3 weeks in the Animal House of the College of Veterinary Medicine, and they were fed standard pellets and water. These animals were divided into 5 groups containing 10 mice each: 1st one: control group treated with normal saline; 2nd Group infected with 0.1ml of Aspergillus flatus intraperitoneally; 3rd group infected with Aspergillus ochraceus 0.1ml intraperitoneally (IP); 4th group infected with 0.1ml Aspergillu niger IP; 5th group mice infected with Cryptococcus neoformans 0.1ml IP at single dose. After 3 weeks animals were scarified. Histopathological examination, in general, reports high incidences of necrotic lesions with granuloma and severe destructive changes, mainly in areas containing fungi hyphae that appear very clearly enclosed to necrotic and inflammatory foci, lung tissues suffering from prominent interstitial pneumonia with thick exudation, mainly fibrinous type. Liver tissues show massive necrosis with Kupfer cells and other inflammatory cell proliferation and evidence of apoptosis. Kidney samples appear with heavy degenerative changes ranging from swelling tubules to necrosis associated with severe inflammation caused by pyelonephritis and phlebitis. also, we saw fungi in the affected area. Spleen shows severe depletion and megakaryocyte proliferation and necrotic lesion. Fungi naturally infects occurs in pet animals and can transmitted to other animals in different environmental; area and can causes severe pathological lesions.

An account of chromosomal damage in PMCs of stripe rust infected barley

A study, on the effects of natural mild fungal infection on meiosis of Barley Pollen Mother Cells (PMCs), was done in order to analyze the chromosomal damage elicited by the pathogenic conditions. A pattern similar to common mutagens, of reduction in mitotic index and chiasma frequency, as well as, production of various aberrations that demonstrate chromosomal damage, was observed. The most common abnormalities were un-orientation and other spindle related aberrations, as well as stickiness and clumping of chromosomes. The disease induced a reduction in pollen viability as compared to the control plants. The results were compared with those of a high dose of a known mutagen ie gamma rays in order to draw commonalities between the two conditions.

Status of Infection during a Natural Outbreak of Brucellosis in Unvaccinated Buffaloes at a Livestock Farm of Madhya Pradesh in India by using Competitive Enzyme-linked Immunosorbent Assay

Background: Brucellosis is one of India’s most important bacterial diseases of large ruminants. It is of economic importance. It is caused by members of the Brucella species and responsible for abortion in pregnant bovines usually during the first term and generally after the fifth month of gestation. Hence, livestock farm with a history of abortion in pregnant animals has to be investigated for Brucellosis. Methods: Whole blood samples (of 50 individual buffaloes) were collected aseptically from a herd of buffaloes experiencing a natural outbreak of Brucellosis. Extracted serum samples were tested after clarification in commercially procured competitive enzyme-linked immunosorbent assay for the serological laboratory diagnosis of Brucellosis. Result: Out of 50 buffalo serum samples tested by using commercially procured competitive enzyme-linked immunosorbent assay, a total of 24 buffalo serum samples tested positive for the presence of Antibodies against Brucella species. Overall seropositivity of 48% was recorded for Brucellosis in the investigated buffalo herd experiencing a natural infection in the present study even after long-term storage of serum samples at deep freezing conditions.

Sero-epidemiological study and infection rate evaluation of pertussis in Henan Province

Objective: To analyze the epidemiological distribution characteristics, influencing factors, and infection rates of pertussis in the population of Henan Province. Methods: From 2022 to 2023, a cross-sectional survey was conducted to investigate the permanent population in Henan Province. Enzyme-linked immunosorbent assay (ELISA) was used to detect anti-pertussis toxin IgG (PT-IgG), analyze the antibody positivity rate (≥20 IU/ml) and median concentration (MC), and estimate the pertussis infection rate based on PT IgG ≥40 IU/ml. The rank sum test was used to compare antibody levels among groups, and the χ2 test was used to compare antibody positive rates and infection rates among groups. Results: A total of 4 810 research subjects were included in this study. The overall positive rate of PT-IgG was 12.10% and MC was 3.04 (0.35, 10.36) IU/ml. There were significant differences both in positive rates and antibody levels of PT-IgG among different regions or age groups (region positive rate: χ2=134.06, P<0.001, MC: H=337.74, P<0.001; age group positive rate: χ2=45.27, P<0.001, MC: H=134.49, P<0.001). Both the positive rate of PT-IgG (25.26%) and MC (8.01 IU/ml) were the highest within one year after completing a full course of vaccination. There were significant differences in positive rates and antibody levels among people receiving different types of pertussis vaccines (positive rate: χ2=12.38, P=0.006, MC: H=17.93, P<0.001). The antibody positivity rate (35.71%) and MC (8.88 IU/ml) of the people who received cell-free pertussis inactivated poliomyelitis influenza type b (combined) vaccine throughout the course were higher than those who received other types of vaccines. The natural infection rate of pertussis was evaluated for individuals aged≥3 years who had no history of pertussis vaccine immunization within the year prior to sampling. With a high vaccination rate, the estimated infection rate of pertussis in the population was 5 757.22/100 000. The infection rates in the 3-year-old (1 940.16/100 000) and 4-year-old (1 765.68/100 000) populations were at a low level among the entire population, reaching their peak at the age of 6 (12 656.71/100 000). Subsequently, although the infection rate continued to decline, it remained at a high level and peaked again at the age of 40-49 years (8 740.39/100 000). There was a statistically significant difference in the estimated infection rate of pertussis among different age groups (χ2=53.21, P<0.001). Conclusion: The PT-IgG level of pertussis in the population of Henan Province is generally at a low level. The estimated infection rate of pertussis is much higher than the reported incidence rate. A booster dose of pertussis vaccine is recommended at 6 years old.

IgG, IgM, and Nonstructural Protein 1 Response Profiles after Receipt of Tetravalent Dengue Vaccine TAK-003 in a Phase 2 Randomized Controlled Trial.

The profiles of vaccine-induced dengue antibodies may differ from those produced following natural infection and could potentially interfere with the interpretation of diagnostic tests. We assessed anti-dengue IgG and IgM antibodies, and nonstructural protein 1 antigen profiles in the serum of adults who received a single dose of the tetravalent dengue vaccine TAK-003 as either an initially developed high-dose formulation or the standard approved formulation in a phase 2 study in Singapore (#NCT02425098). Immunoglobulin G and IgM profiles during the first 30 days postvaccination varied by baseline serostatus (microneutralization assay). Nonstructural protein 1 antigen was not detected in the serum of any participants. Vaccine-induced IgG and IgM antibodies can affect serological confirmation of subsequent dengue infection in vaccinees. These results highlight the limitations of using serological tests for dengue diagnosis, particularly in a postvaccination setting, and emphasize the need for more sensitive antigen- and molecular-based testing for accurate dengue diagnosis.

Anti-SARS-CoV-2 total immunoglobulin and neutralising antibody responses in healthy blood donors throughout the COVID-19 pandemic: a longitudinal observational study.

Quantifying antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and neutralising antibodies may help to understand protection at the individual and population levels. Determination of neutralising antibodies using classical virus neutralisation tests (VNT) is considered the gold standard, but they are costly and time-intensive. Enzyme-linked immunosorbent assay (ELISA)-based surrogate VNTs (sVNT) or anti-SARS-CoV-2 spike protein receptor binding domain immunoglobulins (anti-S-RBD Ig) may be suitable alternatives to VNTs. We aimed to (a) explore the correlations between anti-S-RBD Ig, VNT, and sVNT measurements and (b) describe humoral immunity against SARS-CoV-2 after vaccination, natural infection, and vaccine breakthrough infection in healthy blood donors. We measured total anti-SARS-CoV-2 Ig in 5714 serum samples from 2748 healthy individuals visiting the Swiss Red Cross Blood Donation Centre in Basel from 03/2020 to 04/2022. We used the Elecsys®Anti-SARS-CoV-2 immunoassay (Roche) against the N- and S-receptor binding domain (RBD) proteins. In a subset of 548 samples from 123 donors, we conducted sVNTs against the Wuhan wild-type SARS-CoV-2 (SARS-CoV-2 Neutralizing Antibodies Detection Kit; Adipogen™). In 100 samples from 40 donors, we correlated sVNT and VNTs against the wild-type (D614G WU1) virus. Surveys were sent to the blood donors to collect data on their SARS-CoV-2 infection and vaccination status. Using this data, donors were categorised as "vaccination only", "infection before vaccination", "post-vaccine breakthrough infection", and "natural infection only". Our longitudinal observation study cohort consisted of 50.7% males with a median age of 31 years (range 18-75 y). Anti-SARS-CoV-2 N protein positivity rates per month indicate 57.1% (88/154) of the cohort was infected up to 04/2022. No differences in seropositivity were found between sexes, age groups, blood types (AB0 or RhD), and cytomegalovirus serostatus. We observed a high correlation between anti-S-RBD Ig and inhibition percentage (Spearman'sρ= 0.92, Kendall'sτ= 0.77, p <0.0001). We determined the sensitivity and specificity for the manufacturers' thresholds for detecting virus-neutralising effects and computed the "best" cut-off based on our real-world data. We categorised 722/1138 (63.5%) donors as vaccination only (82.3%), post-vaccine breakthrough infection (7.8%), infection before vaccination (5.8%), and natural infection only (4.2%). We observed a lower inhibition percentage in the natural infection-only group than in all other vaccinated groups. The infection before vaccination group had higher anti-S-RBD Ig titres after the first vaccine dose than the other vaccinated groups. In total, 57.1% of healthy blood donors were infected with SARS-CoV-2, but natural infection without evidence of vaccination seems to result in substantially lower neutralising antibody levels. An estimate of antibody neutralisation may be helpful to assess reinfection risk. Total anti-S-RBD Ig correlates with surrogate virus neutralisation test results, a surrogate for neutralisation; therefore, we suggest that total anti-S-RBD Ig may estimate the level of neutralising antibodies. The threshold for protection from an unfavourable clinical outcome must be evaluated in prospective clinical cohorts.

Pathogenicity of Lasiodiplodia theobromae isolated from cocoa dieback disease in South Sulawesi, Indonesia

AbstractDieback disease is one of the constraints to cocoa production in Indonesia. A newly identified dieback symptom has been observed in cocoa farms in East Luwu since 2015 and later observed in Luwu, Pinrang, Enrekang and Soppeng Regency, South Sulawesi. The potential causal agent identity was determined using morphological characteristics, DNA sequences, and phylogenetic analyses. A total of four fungal isolates out of seven isolates that were recovered from diseased stems morphologically resembled Lasiodiplodia species. ITS and EF1α sequencing confirmed that three of the Lasiodiplodia isolates were Lasiodiplodia theobromae, and one isolate was Lasiodiplodia pseudotheobromae. The aggresiveness of all fungal isolates and control was further determined by a leaf disk assay. Experiments showed that L. theobromae isolate CAS0321 was the most aggressive isolate in a leaf disk assay, while other Lasiodiplodia isolates, Fusarium isolates and Diaporthe isolate, were less aggressive. L. theobromae isolate CAS0321 was further used for a pathogenicity test on cocoa seedlings. Two months after inoculation, L. theobromae isolate CAS0321 caused elongated streaks on seedling stems with dark brown to black streaking of vascular tissues similar to that observed in natural infections. This is the first report of a virulent isolate of L. theobromae associated with cocoa dieback in Sulawesi.

Global epidemiology of severe fever with thrombocytopenia syndrome virus in human and animals: a systematic review and meta-analysis

Since the initial identification of the Severe Fever with Thrombocytopenia Syndrome (SFTS) in ticks in rural areas of China in 2009, the virus has been increasingly isolated from a diverse array of hosts globally, exhibiting a rising trend in incidence. This study aims to conduct a systematic analysis of the temporal and spatial distribution of SFTS cases, alongside an examination of the infection rates across various hosts, with the objective of addressing public concerns regarding the spread and impact of the disease. In this systematic review and meta-analysis, an exhaustive search was conducted across multiple databases, including PubMed, Web of Science, Embase, and Medline, CNKI, WanFang, and CQVIP. The literature search was confined to publications released between January 1, 2009, and May 29, 2023. The study focused on collating data pertaining to animal infections under natural conditions and human infection cases reported. Additionally, species names were unified using the National Center for Biotechnology Information (NCBI) database. The notification rate, notification death rate, case fatality rate, and infection rates (or MIR) were assessed for each study with available data. The proportions were pooled using a generalized linear mixed-effects model (GLMM). Meta-regressions were conducted for subgroup analysis. This research has been duly registered with PROSPERO, bearing the registration number CRD42023431010. We identified 5492 studies from database searches and assessed 238 full-text studies for eligibility, of which 234 studies were included in the meta-analysis. For human infection data, the overall pooled notification rate was 18.93 (95% CI 17.02-21.05) per ten million people, the overall pooled notification deaths rate was 3.49 (95% CI 2.97-4.10) per ten million people, and the overall pooled case fatality rate was 7.80% (95% CI 7.01%-8.69%). There was an increasing trend in notification rate and deaths rate, while the case fatality rate showed a significant decrease globally. Regarding animal infection data, among 94 species tested, 48 species were found to carry positive nucleic acid or antibodies. Out of these, 14 species were classified under Arthropoda, while 34 species fell under Chordata, comprising 27 Mammalia and 7 Aves. This systematic review and meta-analysis present the latest global report on SFTS. In terms of human infections, notification rates and notification deaths rates are on the rise, while the case fatality rate has significantly decreased. More SFTSV animal hosts have been discovered than before, particularly among birds, indicating a potentially broader transmission range for SFTSV. These findings provide crucial insights for the prevention and control of SFTS on a global scale. None.