Positive qPCR Research Articles

Retrospective investigation of porcine circoviruses in cases of porcine dermatitis and nephropathy syndrome

Porcine dermatitis and nephropathy syndrome (PDNS) is a severe condition that affects mainly growing pigs and is considered to be caused by a type III hypersensitivity reaction. Although porcine circovirus 2 (PCV-2) is the antigen linked to this condition, porcine circovirus 3 (PCV-3) has also been proposed to be causally associated with PDNS. Moreover, the initial description of porcine circovirus 4 (PCV-4) also related this novel agent to this clinicopathological entity. Therefore, this retrospective study included a large number of PDNS cases (n = 102) fulfilling specific histologic criteria in search of known porcine circoviruses (PCV-1 to PCV-4) by conventional and/or quantitative PCR (qPCR). All the samples were subjected to PCV-2 immunohistochemistry (IHC) or conventional in situ hybridization (C-ISH), and RNAscope® (R-ISH) was used to study PCV-2 and PCV-3 localization in a subset of the samples. All PDNS cases were PCV-2 positive by qPCR, while 30 of them (29.4%) yielded PCV-3 qPCR positivity; PCV-2 viral loads were significantly greater than PCV-3 viral loads. All animals were negative for PCV-1 and PCV-4. By C-ISH/IHC, 63 cases (61.8%) were positive for PCV-2, with low to moderate amounts of antigen. R-ISH demonstrated higher sensitivity, as all studied cases were positive; however, neither PCV-2 nor PCV-3 were consistently found within characteristic PDNS lesions. These results indicate that all PDNS-affected pigs were infected with PCV-2, emphasizing the likelihood that this viral antigen is causally linked to this condition. In contrast, no evidence of the association of PCV-1, PCV-3 or PCV-4 with PDNS was found.

A-238 Lyophilized Bead Multiplex Assays for CT/NG/TV Detection

Abstract Background Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Trichomonas vaginalis (TV) cause the three most prevalent sexually transmitted infectious diseases in developed countries, contributing to approximately 300 million new infections worldwide, annually. Due to the challenges of culturing and using immunoassays to detect these pathogens, DNA-based molecular tests have been instrumental, and current trends in molecular testing for CT/NG/TV have moved toward point-of-care tests. Lyophilization provides benefits required for point-of-care tests, such as ambient storage, extended shelf life, simplified downstream workflow, and variable formats. A lyophilized-bead format enables an assay to be placed in sealed consumables and stored at room temperature for up to two years. An additional consideration is the need for endogenous and exogenous controls. Exogenous in-process controls can be used to validate the performance of workflows culminating in a qPCR reaction and provide flexibility to test developers. An ideal exogenous in-process control is nonhomologous to human or human pathogen genome sequences and does not align with primers or probes designed for pathogen detection. The objective of the current study was to develop a lyophilized-bead-format assay containing an ideal exogenous control and establish whether it is a valid option for the accurate detection of CT, NG, and TV. Methods A synthetic DNA control containing targets for CT/NG/TV/RNase P (RP)/exogenous control was used to establish an analytical LOD by qPCR. The 5-plex assay, lyophilized in beads, was hydrated and tested for linearity over an 8-log range of the synthetic DNA control. Further, the qPCR lyophilized bead with assay was tested with a proficiency sample by extracting DNA from ZeptoMetrix NATtrol CT/NG/TV Positive Control and spiking-in the exogenous DNA control. qPCR was performed on the extracted DNA and human cDNA. Results The analytical LOD for the control DNA was determined to be 5 copies/reaction. Additionally, linearity was observed by qPCR over an 8-log range of the synthetic DNA control for all five targets in multiplex with good efficiencies and R2 values. Finally, all targets were amplified and detected by qPCR using DNA extracted from ZeptoMetrix NATtrol CT/NG/TV Positive Control with spiked-in exogenous DNA control. The detection of the exogenous sequence in the qPCR multiplex reaction indicated the extraction was successful. Conclusions We have developed a multiplex qPCR assay in lyophilized-bead format that can identify infectious agents, such as CT/NG/TV, in a single reaction. We have included RP as a human host control, plus an exogenous in-process control, for a total of 5-plex in separate fluorescent channels. We have shown that our lyophilized beads with assay produce a positive qPCR result when combined with a proficiency sample.

Humans seropositive for Trypanosoma cruzi co-infected with intestinal helminths have higher infectiousness, parasitaemia and Th2-type response in the Argentine Chaco

BackgroundThe Gran Chaco ecoregion is a well-known hotspot of several neglected tropical diseases (NTDs) including Chagas disease, soil-transmitted helminthiasis and multiparasitic infections. Interspecific interactions between parasite species can modify host susceptibility, pathogenesis and transmissibility through immunomodulation. Our objective was to test the association between human co-infection with intestinal parasites and host parasitaemia, infectiousness to the vector and immunological profiles in Trypanosoma cruzi-seropositive individuals residing in an endemic region of the Argentine Chaco.MethodsWe conducted a cross-sectional serological survey for T. cruzi infection along with an intestinal parasite survey in two adjacent rural villages. Each participant was tested for T. cruzi and Strongyloides stercoralis infection by serodiagnosis, and by coprological tests for intestinal parasite detection. Trypanosoma cruzi bloodstream parasite load was determined by quantitative PCR (qPCR), host infectiousness by artificial xenodiagnosis and serum human cytokine levels by flow cytometry.ResultsThe seroprevalence for T. cruzi was 16.1% and for S. stercoralis 11.5% (n = 87). We found 25.3% of patients with Enterobius vermicularis. The most frequent protozoan parasites were Blastocystis spp. (39.1%), Giardia lamblia (6.9%) and Cryptosporidium spp. (3.4%). Multiparasitism occurred in 36.8% of the examined patients. Co-infection ranged from 6.9% to 8.1% for T. cruzi-seropositive humans simultaneously infected with at least one protozoan or helminth species, respectively. The relative odds of being positive by qPCR or xenodiagnosis (i.e. infectious) of 28 T. cruzi-seropositive patients was eight times higher in people co-infected with at least one helminth species than in patients with no such co-infection. Trypanosoma cruzi parasite load and host infectiousness were positively associated with helminth co-infection in a multiple regression analysis. Interferon-gamma (IFN-γ) response, measured in relation to interleukin (IL)-4 among humans infected with T. cruzi only, was 1.5-fold higher than for T. cruzi-seropositive patients co-infected with helminths. The median concentration of IL-4 was significantly higher in T. cruzi-seropositive patients with a positive qPCR test than in qPCR-negative patients.ConclusionsOur results show a high level of multiparasitism and suggest that co-infection with intestinal helminths increased T. cruzi parasitaemia and upregulated the Th2-type response in the study patients.Graphical

Resurgence of Bordetella pertussis, including one macrolide-resistant isolate, France, 2024.

As other European countries, France is experiencing a resurgence of pertussis in 2024. Between 1 January and 31 May 2024, 5,616 (24.9%) positive Bordetella pertussis qPCR tests were identified, following a 3-year period of almost null incidence. Of 67 cultured and whole genome sequenced B. pertussis isolates, 66 produced pertactin and 56 produced FIM2, in contrast to pre-COVID-19 years. One isolate of genotype Bp-AgST4 was resistant to macrolides. Pertussis resurgence may favour isolates that produce FIM2 and pertactin.

Molecular Characterization of Leptospira Species among Patients with Acute Undifferentiated Febrile Illness from the Municipality of Villeta, Colombia.

Leptospira is a bacterial genus that includes several pathogenic species related to leptospirosis. In Colombia, leptospirosis is a mandatorily reported disease, widely distributed across the country. In the Villeta municipality, leptospirosis has been identified as an important cause of febrile illness; however, to date, no studies have been performed to identify the circulating species. A genus-specific qualitative qPCR was performed on DNA extracted from febrile patients' acute-phase whole-blood samples targeting a fragment of the rrs gene. Positive qPCR samples were further amplified for the adk, icdA, LipL32, LipL41, rrs, and secY genes through conventional PCR for sequencing. All high-quality obtained sequences were further assessed through concatenated phylogenetic analysis. A total of 25% (14/56) of febrile patients' acute blood samples were positive for Leptospira spp. High-quality sequences were obtained for only five genes, and analysis through concatenated phylogeny identified that all sequences clustered within the P1/pathogenic clade; some of them formed a robustly supported clade with Leptospira santarosai, and others were closely related with other Leptospira species but exhibited considerable genetic divergence. We describe the presence of pathogenic Leptospira species among febrile patients from the Villeta municipality and identify L. santarosai and other Leptospira species as causative agents of leptospirosis in the region.

Environmental Fungal Contamination Characterization of Three Inpatient Units Utilizing Optimized Detection Methods

Background: Environmental sampling and detection methods for fungi in healthcare settings are not well-established. We previously refined methods for fungal sampling and detection in a controlled laboratory environment and aimed to validate them in a real-world healthcare setting. Methods: We performed a microbiological analysis of air and surfaces in three inpatient units at a tertiary care center. Surface samples were obtained with foam sponges from 3 locations in patient rooms (Patient bedrails, bathroom floor, HVAC export) and 5 locations in units (HVAC exports 3x, clean linen storage, soiled linen storage). Air samples were taken with an active air sampler directly below HVAC exports. Sponges were processed using the stomacher technique. Samples underwent DNA extraction followed by qPCR with FungiQuant primers targeting the 18S rRNA gene. Amplicons from positive samples were sequenced (NextSeq 1000, 300bp PE) and SmartGene databases were used to interpret sequence data. For comparison to culture methods, samples were also plated onto Sabouraud and HardyCHROM Candida + auris medias. Fungal growth underwent DNA extraction, 18S PCR and Sanger sequencing for genus and species identification. Results: A total of 85 samples were obtained, from 15 patient rooms and three units resulting in 61 surface and 24 air samples. Patients in study rooms had a median age of 53, 9 (60%) were male, and no patients had an invasive fungal infection during their hospital encounter. 44 (53%) and 39 (46%) samples were positive for fungi via qPCR and culture, respectively. Of the 44 positive qPCR samples, microbiome analyses identified at least one fungi to the species, genus and family levels in 43 (98%), 28 (64%), 18 (41%) samples, respectively (Table 1). 114 total isolates were identified of which the most common were Mallassezia restricta (30 [26%]), Malassezia globose (29 [25%]), and Pennicillium paradoxum (4 [4%]). 39 genera were identified of which the most common were Mucor (19 [49%]) and Candida (8 [21%]). Of the 39 culture positive samples, 90 total isolates were recovered. The most common species were Paradendryphiella arenariae (19 [21%]), Aspergillus niger (12 [13%]) and Penicillium commune (12 [13%]). Conclusion: These results demonstrate the presence of diverse fungal species in both air and surface samples across inpatient units. Higher sensitivity was noted utilizing qPCR, however, identified genera and species were markedly different between qPCR and culture methods. Larger studies are needed to assess the efficacy of qPCR for fungal detection in the healthcare environment.

New insights into swine dysentery: faecal shedding, macro and microscopic lesions and biomarkers in early and acute stages of Brachyspira hyodysenteriae infection

BackgroundSwine dysentery (SD) is a severe mucohaemorrhagic colitis in pigs caused classically by Brachyspira hyodysenteriae. Although several aspects of B. hyodysenteriae infection dynamic are already described, further research in the early stage of this infection is required. In this study, 7-week-old pigs were orally challenged with B. hyodysenteriae to obtain information about faecal shedding, macro and microscopic intestinal lesions and serum acute phase proteins in pigs at the onset of B. hyodysenteriae shedding (early infection group, n = 8), in pigs with mucohaemorrhagic diarrhoea (acute infection group, n = 8) and in non-infected controls (n = 16).ResultsFirst B. hyodysenteriae detection by q-PCR and first loose stools with blood and mucus occurred both at 8 days post-inoculation. The lapse between a positive q-PCR and observation of mucohaemorrhagic diarrhoea ranged from 0 to 3 days, except in a single pig in which this period lasted 5 days. Macroscopic lesions were observed in the large intestine from both infected groups although more frequent and severe in acute infection group. Microscopic observation of the apex mucosa revealed that in early infection only higher ulceration values were observed compared to healthy controls. In contrast, the acute infection group exhibited higher ulceration, neutrophils infiltration and increased mucosal thickness compared to the other two groups. Among the serum biomarkers tested, only haptoglobin, C-reactive protein, and creatine kinase showed a significant increase in pigs in the acute infection period compared to controls, whereas haptoglobin was the only factor with a significant increase at the early infection compared to non-infected animals.ConclusionsThis study provides new insights about SD and remarks the complex and limited options to perform an early detection of infected animals beyond PCR diagnosis.

Evaluation of eDNA qPCR monitoring as an early detection tool for a non-native mysid in Great Lakes Waters

Early detection of aquatic invasive species (AIS) is vital to cost-effective prevention of their spread in the Great Lakes. Unfortunately, AIS surveillance has been generally too slow and geographically limited to support this purpose. Environmental DNA (eDNA) detection using quantitative polymerase chain reaction (qPCR) offers more rapid and affordable detection of likely AIS presence, but it does not directly discern live/dead status. Vital status verification using conventional surveys following positive eDNA qPCR detections could resolve this barrier, but only if the latter are adequately reliable and sensitive. Here we explore the reliability and sensitivity of eDNA qPCR monitoring for the bloody red shrimp (Hemimysis anomala), an AIS established in the southern Great Lakes but not yet widely distributed in Lake Superior, against conventional microscopy-based methods. We conducted this comparison using 1) harbor water from Muskegon Lake, MI where H. anomala is established, and 2) raw ballast water from ships transporting ballast from lower Lake Michigan to western Lake Superior. Our studies showed positive eDNA qPCR detections of H. anomala in all harbor and ballast samples for which conventional detection results were positive, and in some samples for which conventional results were negative. These results suggest that qPCR assays with adequate specificity could be an important tool in support of more effective and affordable early detection of target species in Great Lakes water, especially when combined with confirmatory conventional monitoring.

The frequency and associated factors of typhoid carriage in patients undergoing cholecystectomy for gallbladder disease in Pakistan: A cross-sectional study.

Enteric fever is caused by Salmonella enterica serovars Typhi (S. Typhi) and Paratyphi A, B, and C. It continues to be a significant cause of morbidity and mortality worldwide. In highly endemic areas, children are disproportionately affected, and antimicrobial resistance reduces therapeutic options. It is estimated that 2-5% of enteric fever patients develop chronic asymptomatic infection. These carriers may act as reservoirs of infection; therefore, the prospective identification and treatment of carriers are critical for long-term disease control. We aimed to find the frequency of Salmonella Typhi carriers in patients undergoing cholecystectomy. We also compared the detection limit of culturing versus qPCR in detecting S. Typhi, performed a geospatial analysis of the carriers identified using this study, and evaluated the accuracy of anti-Vi and anti-YncE in identifying chronic typhoid carriage. We performed a cross-sectional study in two centers in Pakistan. Gallbladder specimens were subjected to quantitative PCR (qPCR) and serum samples were analyzed for IgG against YncE and Vi by ELISA. We also mapped the residential location of those with a positive qPCR result. Out of 988 participants, 3.4% had qPCR-positive gallbladder samples (23 S. Typhi and 11 S. Paratyphi). Gallstones were more likely to be qPCR positive than bile and gallbladder tissue. Anti-Vi and YncE were significantly correlated (r = 0.78 p<0.0001) and elevated among carriers as compared to qPCR negative controls, except for anti-Vi response in Paratyphi A. But the discriminatory values of these antigens in identifying carriers from qPCR negative controls were low. The high prevalence of typhoid carriers observed in this study suggests that further studies are required to gain information that will help in controlling future typhoid outbreaks in a superior manner than they are currently being managed.

Prevalence of Hemoplasma spp. positivity in potential feline blood donors and study of the association with selected clinical variables.

Hemotropic mycoplasmas, hemoplasmas, are epi-erythrocytic parasitic bacteria that can be transmitted through blood transfusion. To study the prevalence of hemoplasma infection of potential feline blood donors and investigate the association between Hemoplasma spp. quantitative polymerase chain reaction (qPCR) positivity in blood units and selected variables. Seven thousand five hundred seventy-three blood units from 4121 privately-owned potential donor cats. Retrospective observational cross-sectional study. The Banco Sangue Animal (BSA)-Animal Blood Bank medical database was reviewed for all feline donations performed in 2022 in Portugal, Spain, and Belgium. Baseline characteristics and results of blood-borne pathogens screening tests were extracted from the medical records. Two hundred twelve of 4034 Portuguese donor cats and 2 of 70 Spanish donor cats tested positive for Hemoplasma spp. qPCR in 2022 leading to an overall estimated prevalence of 5.2% (95% CI: 4.5%-5.9%) in potential blood donors. Using multivariable generalized estimation equation models, Hemoplasma spp. qPCR was more often positive among blood units issued from male cats (OR = 1.9, 95% CI: 1.4-2.6, P < .0001), units positive for FeLV (OR = 2.8, 95% CI: 1.4-5.6, P = .0023), and units collected in winter months (OR = 2.5, 95% CI: 1.7-3.6, P < .0001). This study underscores the importance of Hemoplasma spp. and other relevant blood-borne pathogens screening at every donation. Implementing stringent screening protocols is crucial to mitigate the risk of hemoplasma transmission via blood transfusions, thereby safeguarding the health and welfare of cats receiving transfusions.

Development and Evaluation of Mycoplasma gallisepticum Challenge Model in Layer Pullets.

Manufacturers of Mycoplasma gallisepticum (MG) modified live vaccines usually recommend a single application at 8 wk of age. This makes 12-16-wk-old layer pullets suitable for challenge studies intended to evaluate these vaccines. Numerous challenge models in different poultry species and ages have been reported. However, there is not an established layer pullet challenge model for this age. The aim of this study is to develop a suitable challenge model in 12-wk-old layer pullets. MG Rlow strain was used as the challenge strain, and its ability to induce clinical signs and lesions in 12-wk-old Hy-Line W-36 layer pullets was evaluated. Three different doses (low, 7.95 × 104 color-changing units [CCU]/bird; medium, 7.95 × 106 CCU/bird; and high, 7.95 × 108 CCU/bird) via three different routes (eye drop, fine spray, and contact infection) were compared and evaluated using different parameters. At 14 days post-challenge, there were no mortalities in any of the groups throughout the study. Layer pullets directly challenged with the high dose via the fine spray route showed the clearest and most consistent results (clinical signs, positive quantitative real-time PCR [qPCR], seroconversion, air sac scoring, and histopathological changes of the tracheal mucosa). Medium and low challenge doses applied via fine spray or eye drop did not show consistent results. Rlow strain was able to spread to the contact infection birds, as confirmed by the positive qPCR results; however, none of the contact-infected birds showed any clinical signs or gross or microscopic lesions. Our results suggest that a high dose (7.95 × 108 CCU/bird) administered through a fine spray route is the model of choice in any future MG vaccine evaluation trials in 12-wk-old layer pullets.

Comparison of qPCR and metabarcoding for environmental DNA surveillance of a freshwater parasite.

Analysis of environmental DNA (eDNA) has been successfully used across freshwater ecological parasitology to inform management of ecologically and economically important species. However, most studies have used species-specific quantitative polymerase chain reaction (qPCR) assays to detect target taxa. While generally effective, this approach limits the amount of community and management-supporting data that can be obtained from eDNA samples. If eDNA metabarcoding could be conducted with the same accuracy of a single species approach, researchers could simultaneously detect a target species while obtaining vast community data from eDNA samples. We sampled 38 freshwater sites on Fort McCoy, Wisconsin and compared qPCR to metabarcoding for eDNA detection of the ectoparasitic gill louse Salmincola edwardsii, an obligate parasite of Salvelinus fishes (chars). We found no evidence to suggest S. edwardsii occupancy or detection probabilities differed between qPCR and metabarcoding. Further, we found that the number of S. edwardsii reads from metabarcoding were negatively predictive of C T values from qPCR (C T value indicates cycle a significant amount of target eDNA is detected, with lower C Ts indicative of more DNA), demonstrating that our metabarcoding reads positively predicted qPCR DNA quantities. However, the number of reads was not predictive of overall qPCR score (number of positive qPCR replicates). In addition to S. edwardsii, metabarcoding led to the detection of a vast community of over 2600 invertebrate taxa. We underscore the necessity for conducting similar analyses across environments and target species, as the ecology of eDNA will vary on a per-study basis. Our results suggest that eDNA metabarcoding provides a highly sensitive and accurate method for detecting parasitic gill lice while also illuminating the broader biological community and co-occurrence of species in the environment.

Diagnostic Utility of Cytomegalovirus (CMV) DNA Quantitation in Ulcerative Colitis.

Cytomegalovirus (CMV) colitis is a critical condition associated with severe complications in ulcerative colitis (UC). This study aimed to investigate the diagnostic value of the presence of CMV DNA in intestinal mucosa tissue and blood samples in patients with active UC. This study included 81 patients with exacerbated symptoms of UC. Patient data were obtained from the Hospital Information Management System. CMV DNA in colorectal tissue and plasma samples were analyzed using a real-time quantitative PCR assay. CMV markers were detected using immunohistochemistry and hematoxylin-eosin staining. Immunohistochemistry positivity was observed in tissue samples from eight (9.9%) patients. Only one (1.2%) patient showed CMV-specific intranuclear inclusion bodies. CMV DNA was detected in 63.0% of the tissues (median: 113 copies/mg) and in 58.5% of the plasma samples (median: 102 copies/mL). For tissues, sensitivity and the negative predictive value (NPV) for qPCR were excellent (100.0%), whereas specificity and the positive predictive value (PPV) were low (41.9% and 15.7%, respectively). For plasma, sensitivity and NPV were high (100.0%) for qPCR, whereas specificity and PPV were low (48.6% and 24.0%, respectively). CMV DNA ≥392 copies/mg in tissue samples (sensitivity 100.0% and specificity 83.6%) and ≥578 copies/mL (895 IU/mL) in plasma samples (sensitivity 66.7% and specificity 100.0%) provided an optimal diagnosis for this test. The qPCR method improved patient management through the early detection of CMV colitis in patients with UC. However, reliance on qPCR positivity alone can lead to overdiagnosis. Quantification of CMV DNA can improve diagnostic specificity, although standardization is warranted.

Monitoring the Long-Term Effectiveness of Miltefosine in Indian Post-Kala-Azar Dermal Leishmaniasis.

Post-kala-azar dermal leishmaniasis (PKDL), the dermal sequel to visceral leishmaniasis (VL), is characterized by hypopigmented macules (macular) and/or papules and nodules (polymorphic). Post-kala-azar dermal leishmaniasis plays a significant role in disease transmission, emphasizing the need for monitoring chemotherapeutic effectiveness. Accordingly, this study aimed to quantify the parasite burden in PKDL patients after treatment with miltefosine by a quantitative polymerase chain reaction (qPCR). A Leishmania kinetoplastid gene-targeted qPCR was undertaken using DNA from skin biopsy specimens of patients with PKDL at three time points, i.e., at disease presentation (week 0, n = 157, group 1), upon completion of treatment (week 12, n = 39, group 2), and at any time point 6 months after completion of treatment (week ≥36, n = 54, group 3). A cycle threshold (Ct) <30 was considered the cutoff for positivity, and load was quantified as the number of parasites/µg genomic DNA (gDNA); cure was considered when samples had a Ct >30. The parasite load at disease presentation (group 1) was 10,769 (1,339-80,441)/µg gDNA (median [interquartile range]). In groups 2 and 3, qPCR results were negative in 35/39 cases (89.7%) and 48/54 cases (88.8%), respectively. In the 10/93 (10.8%) qPCR-positive cases, the parasite burdens in groups 2 and 3 were 2,420 (1,205-5,661)/µg gDNA and 22,195 (5,524-100,106)/µg gDNA, respectively. Serial monitoring was undertaken in 45 randomly selected cases that had completed treatment; all cases in groups 2 or 3 had a Ct >30, indicating cure. Overall, qPCR confirmed an 89.2% cure (as 83/93 cases showed parasite clearance), and the persistent qPCR positivity was attributed to nonadherence to treatment or unresponsiveness to miltefosine and remains to be investigated.

Use of the Mucorales qPCR on blood to screen high-risk hematology patients is associated with better survival.

Our objective was to determine whether the twice-weekly screening of high-risk hematology patients by Mucorales qPCR on serum affects the prognosis of mucormycosis. Results from all serum Mucorales qPCR tests performed on patients from the hematology unit from January 2017 to December 2022 were analyzed. Patients with positive results were classified as having proven, probable or 'PCR-only' mucormycosis. One-month mortality for the local cohort was compared with that of a national cohort of cases of mucormycosis collected by the French surveillance network for invasive fungal disease ('Réseau de surveillances des infections fongiques invasives en France' (RESSIF)) from 2012 to 2018. From 2017 to 2022, 7825 serum Mucorales qPCR tests were performed for patients from the hematology unit; 107 patients with at least one positive Mucorales qPCR (164 positive samples) were identified. Sixty patients (70 positive samples, median Cq=40) had no radiological criteria for mucormycosis and were considered not to have invasive fungal disease (70/7825, 0.9% false positives). It was not possible to classify disease status for six patients (12 positive samples, median Cq=38). Forty-one patients (82 positive samples, median Cq=35) had a final diagnosis of mucormycosis. In comparison with the RESSIF cohort, the local cohort was independently associated with a 48% lower one-month all-cause mortality rate (age-, sex-, and primary disease-adjusted hazard ratio=0.52; 95% confidence interval: 0.29-0.94; P 0.03). Proactive screening for invasive mold diseases in high-risk hematology patients, including twice-weekly Mucorales qPCR on serum, was associated with mucormycosis higher survival.

Snake Fungal Disease in Free-Ranging Northern Pine Snakes (Pituophis melanoleucus melanoleucus) in New Jersey: Lesions, Severity of Sores and Investigator's Perceptions.

Ophidiomyces ophidiicola, the fungus causing snake fungal disease (SFD), has been identified in northern pine snakes (Pituophis melanoleucus) in New Jersey. In this paper, we (1) review the positivity rate of SFD on different locations on snakes' bodies, (2) determine the relationship between the sores and quantitative polymerase chain reaction (qPCR) positivity rates, and (3) explore the relationship between the investigators' clinical evaluation of the severity of sores, their evaluation of the likelihood of the sores being positive, and the qPCR positivity of SFD for the sores. Swabbing the sores was more effective at determining whether the snakes tested positive for O. ophidiicola than ventrum swabbing alone. The perception of the severity of the sores did not relate to qPCR positivity for O. ophidiicola. We suggest that the assessment of the rate of SFD among snakes in the wild needs to include the sampling of snakes with no clinical signs, as well as those with sores, and the swabbing of all the sores collectively. Clear terminology for sores, the identification of clinical signs of SFD, and distinguishing the rates of O. ophidiicola by PCR testing should be adopted. Overall, the pine snakes exhibited a higher rate of sores and positivity of O. ophidiicola swabs by PCR testing compared to the other snakes.

Epidemiology of Pathogenic Retroviruses and Domestic Cat Hepadnavirus in Community and Client-Owned Cats in Hong Kong.

Understanding the local epidemiology of feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) in Hong Kong will inform retrovirus prevention strategies. Domestic cat hepadnavirus (DCH), a novel hepatitis-B-like virus, is commonly detected among client-owned cats in Hong Kong, but community cats have not been studied. The aims of this study were to investigate the frequency and potential risk factors for (i) FeLV and FIV among community and client-owned cats and (ii) perform molecular detection of DCH among community cats in Hong Kong. Blood samples from 713 cats were obtained from client-owned (n = 415, residual diagnostic) and community cats (n = 298, at trap-neuter-return). Point-of-care (POC) testing for FeLV antigen and feline immunodeficiency virus (FIV) anti-p15 and p24 antibodies was performed. FeLV-positive samples were progressed to p27 sandwich enzyme-linked immunosorbent assay. Whole blood DNA was tested with qPCRs for FeLV U3 and gag, and nested PCRs where additional information was required. DCH qPCR was performed on a subset of community cats (n = 193). A single, regressive, FeLV infection was detected in a client-owned cat (1/415 FeLV U3 qPCR positive, 0.2%, 95% CI 0.0-1.3%). Five/415 client-owned cats tested presumably false FeLV-antigen positive (qPCR negative). No markers of FeLV infection were detected in community cats (0/298; 0%). FIV seroprevalence was much higher in community cats (46/298, 15.4%) than in client-owned cats (13/415, 3.1%) (p < 0.001). Mixed breed was a risk factor for FIV infection in client-owned cats. Neither sex nor age were associated with FIV infection. DCH DNA was detected in 34/193 (17.6%) community cats (median viral load 6.32 × 103 copies/reaction). FeLV infection is rare in Hong Kong, negatively impacting the positive predictive value of diagnostic tests. FeLV-antigen testing remains the screening test of choice, but confirmation of a positive result using FeLV qPCR is essential. FIV infection is common in community cats and the absence of a sex predisposition, seen previously in cats managed similarly, raises questions about virus-transmission dynamics in these groups. DCH infection is very common in Hong Kong, both in client-owned and community cats, highlighting the importance of understanding the pathogenic potential of this virus for cats.

The relationships among Leishmania infantum and phyllostomid bats assessed by histopathological and molecular assays

Bats have been reported as reservoir host of Leishmania spp. worldwide, mostly by molecular detection. However, it is still unclear whether bats act as reservoirs of Leishmania infantum to sandflies vectors. In this sense, the investigation of amastigotes forms in the target organs, and the characterization of their associated inflammation, may help to clarify the epidemiological importance of bats in endemic areas for leishmaniasis. The aim of this work was to investigate the host-parasite relationships under microscopic evaluation and predict the epidemiological role of two phyllostomid bats species naturally infected by L. infantum in an endemic area for human leishmaniasis. Fragments of skin, liver and spleen of L. infantum positive and negative bats (Artibeus planirostris and Carollia perspicillata) by qPCR, were studied by histological and immunohistochemical techniques. Both groups, positive and negative, did not show differences in the histopathological study, presenting only discrete tissue changes. Liver and skin showed mild inflammatory reactions. Findings on spleen consisted of reactivity of the lymphoid follicles, expressive presence of apoptotic cells and macrophages containing abundant phagocytic cells debris. We did not find amastigote forms in tissues by histological and IHC techniques in positive qPCR bats. Our results allow us to hypothesize that phyllostomid bats seem to have an important role in reducing the risk of transmission, possibly acting as dead-end host.

Evaluation of parasitemia by qPCR in patients with chronic Chagas disease treated with benznidazole

Objective: To evaluate parasitemia by qPCR in patients undergoing etiological treatment and followed in a Brazilian reference center. Methods: Parasite load was quantified by qPCR in 32 participants with chronic Chagas disease who were treated with benznidazole. Serological analyses were performed before and after the treatment and parasite loads were compared prior and 12/18 months post the treatment. Results: Thirty-two participants were recruited and treated with benznidazole, and 20 were followed-up. Adverse events (AE) were observed in 22 out of 29 participants that had safety data (76%), and dermatological alterations were the most frequently observed AE. Of the 20 participants analyzed, 13 and 7 completed 12 and 18 months follow-up after the treatment, respectively. 12 Months after the final treatment, Trypanosoma cruzi was detectable in 3 patients by qPCR; 18 months after the final treatment, Trypanosoma cruzi was detectable per qPCR in 4 of the 7 participants. Thus, between 12 and 18 months, 7 participants of the 20 initial follow-up cases showed positive qPCR, indicating treatment failures. Conclusions: qPCR can be used as an alternative method for evaluating the effectiveness of the etiological treatment of CD, and can be applied to analyze early therapeutic failures. The study showed that benznidazole therapy had limited effectiveness in treating chronic CD patients, thus emphasizing the importance of conducting continued research for developing more effective therapies and diagnosis for CD.

Multiparametric Flow Cytometry-MRD Assay: Lesson from Phase II Trail REL AML 001

Background: Core-binding factor (CBF) AML with RUNX1/RUNX1T1 (AML1/ETO) and CBFB/MYH11 fusion genes is known as a heterogenous group, accounting for about 10% to 15% of AML. In the Phase II Trial REL AML 001 (EudraCT Number 2017-002094-18; ClinicalTrials ID: NCT 03686345) adult CBF leukemia patients treated with a continuation therapy with Midostaurin were included, and the measurable residual disease (MRD) was performed by molecular MRD assessment (qPCR) and multiparametric flow cytometric-MRD (MCF-MRD) assay. The findings of MCF-MRD assay were compared to qPCR. Methods: 31 patients with AML1/ETO (n=15) and CBFB/MYH11 (n=16) were evaluated between December 2018 to July 2022 with both techniques. A total of 145 determinations (n. AML1/ETO = 56 and n. CBFB/MYH11= 89) were performed. MCF panel included 2 10-color tubes: CD15 FITC/ CD56 PE/ CD34 PerCP-cy5.5/ CD117 PE-cy7/ CD7 APC/ CD13 APC-R700/ CD19 APC H7/ HLADR V450/ CD45 V500C/ CD33 BV630, specific for RUNX1/RUNX1T1 cases and CD64 FITC/ CD2 PE/ CD34 PerCP-cy5.5/ CD117 PE-cy7/ CD200 APC/ CD13 APC-R700/ CD14 APC H7/ HLADR V450/ CD45 V500C/ CD33 BV630, specific for CBFB/MYH11 cases. A mean of 1,733,240 CD45 positive events were acquired, with a mean lower limit of detection (LLOD) of 0.001% (ranging 0.01-0.0003%). In 10 cases (6 RUNX1 and 4 CBFB/MYH11) the molecular and phenotypical features at onset were not available. MCF analyses were performed by InfinicytTM software and reference image tool was used wherever possible. Results: We found a concordance of 76% between MCF cases and RUNX1/RUNX1T1 qPCR, and a concordance of 83% between MCF cases and CBFB/MYH11 qPCR (Tables 1a and 1b). In relapsed cases we observed a dynamic and continuous increase of abnormal MCF events, that was not found in cases without clinical relapse although with positive qPCR (Table 2). The HLADR expression evaluated as the geo mean intensity at presentation and/or at relapse resulted higher in RUNX1/RUNX1T1 patients than in CBFB/MYH11 cases (29845 vs 8979, respectively, p=0.0039 Figure 1). Interestingly, we found in a single case with atypical CBFB/MYH11 fusion gene a high value of HLADR geo mean (44522). The down-regulated expression of HLADR in CBFB/MYH11 blasts may be a useful clue to distinguish AML blasts from the scarcely represented normal CD2 positive myeloid precursors, and from the strongly HLADR positive elements that are found in a regenerating bone marrow background. Conclusion: Although MCF-MRD assay showed lower sensitivity than CBF qPCR, MCF offered interesting informations about the dynamics of the abnormal clone size with time, evaluated as the increasing number of MRD clustering events, which may predict an impending relapse.