Complement Fixation Research Articles

Serological prevalence of Brucella spp. at the livestock-human interface in Jordan

Despite its endemic status in the Middle East, key knowledge gaps persist regarding the prevalence, transmission rate, and geographical distribution of both human and livestock brucellosis in Jordan. This study aimed to investigate the seroprevalence of human and livestock brucellosis as well as the incidence of brucellosis in humans in Jordan. A total of 500 human participants (202 exposed and 296 unexposed to livestock) were enrolled in the study. Sampling was conducted at baseline and 1.5 years later. Additionally, a total of 700 livestock were sampled, comprising 20 animals per taxa (camels, cattle, sheep, goats) per site, at both baseline (N = 350) and the 1.5-year follow-up (N = 350). Human participants were longitudinally followed, whereas livestock sampling was conducted opportunistically. Blood samples obtained from both humans and livestock at baseline and follow-up were tested for Brucella spp. serum antibodies using the Rose Bengal test (RBT) and complement fixation test (CFT). The overall seroprevalence of brucellosis in humans at baseline was 3.4 % (95 % CI: 2.0–5.4). Positive test results in humans were detected from all five sites with no significant regional variation observed. Seroprevalence was higher in individuals regularly exposed to livestock (6.1 %; 95 % CI: 3.5–9.9) compared to those not regularly exposed (0.80 %; 95 % CI: 0.10–2.9). Incidence of human brucellosis was 924 seropositives per 100,000 person-years, with all incident seropositives occurring in the livestock-exposed cohort. In livestock, the overall seroprevalence of brucellosis was 5.4 % (95 % CI: 3.5–8.3) at baseline compared to 2.6 % (95 % CI: 1.4–4.8) at follow-up. Seropositive livestock were detected at all sites apart from Al-Zarqa, and in all species apart from camels. In conclusion: Brucellosis burden was higher among humans regularly exposed to livestock, re-emphasizing the need for disease control in livestock populations to prevent primary infection in humans.

Evaluation of three serological tests for the diagnosis of Brucella suis in dogs using Bayesian latent class analysis

Brucella suis infection of dogs is an emerging issue worldwide requiring specific management to address zoonotic risks and animal welfare concerns. Diagnosis in dogs is routinely based on serological testing, but to date these tests have only been validated for use in production animal species and humans. This study aimed to assess the diagnostic performance of three commonly used serological tests in dogs. Canine sera (n = 989) were tested with the Rose Bengal rapid plate agglutination test (RBRPT), the complement fixation test (CFT) and a competitive ELISA (C-ELISA). Diagnostic test performance was evaluated using a three test, two population Bayesian latent class analysis accounting for conditional dependence between the three tests. Positive and negative predictive values (PPV, NPV) were calculated for a range of expected prevalence estimates for the individual tests and test combinations interpreted in series and parallel. The RBRPT showed the highest individual Se of 0.902 (95 % posterior credible interval [PCI] 0.759–0.978) and the CFT the highest individual diagnostic specificity (Sp) of 0.914 (95 % PCI 0.886–0.946). The C-ELISA had marginally the best overall diagnostic performance (Youden’s index = 0.807). The CFT and the C-ELISA interpreted in parallel returned the highest combined Se and Sp (0.988 and 0.885, respectively). All tests returned NPVs of > 0.982 in 2–8 % prevalence settings. Series interpretation of the three-test combination as well as the two-test combinations of the RBRPT and the C-ELISA and the CFT and the C-ELISA produced a PPV of 0.502 when the estimated prevalence was 8 %. While all tests are suitable for the detection of B. suis antibodies in dogs, they should not be interpreted in isolation as their diagnostic value is dependent on the pre-test probability of the disease. As such they are useful tools for the diagnosis of B. suis in dogs when exposure, history and clinical presentation indicate a risk of brucellosis.

Epidemiological Investigation of Animal Brucellosis in Domestic Ruminants in Greece from 2015 to 2022 and Genetic Characterization of Prevalent Strains.

Brucellosis is one of the most important zoonotic diseases in Greece, causing a significant burden on both human and animal vitality as well as economic loss. The present study was conducted from 2015 to 2022 on 711,415 serum samples by determining the seroepidemiology of Brucellosis among livestock in 24 geographical areas in Greece using the Rose Bengal Test (RBT) and the complement fixation test (CFT) and further performing genetic analysis of Brucella spp. by species-specific real-time PCR and MLVA Brucella analysis. A total of 3086 serum samples from goats, sheep, and cattle showed positive results using the RBT and CFT, and only strongly positive samples (n = 800) were preserved in the Βlood Bank of the Veterinary Laboratory of Brucellosis. From these, 212 sera samples were randomly selected for molecular and genetic analysis. The results indicated that the incidence rate of Brucellosis is higher in cattle herds in comparison with other animal species. Overall, 48 samples tested positive by real-time PCR, of which forty-seven of them were B. abortus and one was B. melitensis. Genetic analysis of two B. abortus samples revealed a common pattern, indicating two Bruce04, two Bruce18, four Bruce07, two Bruce09, three Bruce16, and four Bruce30 for both samples, which, interestingly, were not identical with the known genotypes in the public MLVA Brucella database. Our findings substantiate that animal Brucellosis remains a health issue in Greece, with a stable but apparent incidence rate, and further investigation is needed to fully characterize the newly identified Brucella strains in Greece.

Applying a Fluorescence Polarization Assay for Detection of Brucellosis in Animals Using the Fluorescently Labeled Synthetic Oligosaccharides as Biosensing Tracer.

Brucellosis in animals is an infectious disease caused by bacteria of the genus Brucella. Known methods for diagnosing brucellosis face some challenges, due to the difficulties in isolating and standardizing the natural brucellosis antigen. In this work, we investigated the possibility of using the fluorescence polarization assay (FPA) with synthetic glycoconjugate biosensing tracers to detect antibodies against Brucella as a new methodology for diagnosing brucellosis. Based on the received results, the synthetic fluorescein-labeled trisaccharide tracer is most effective for Brucellosis detection. This tracer is structurally related to the immune determinant fragment of the Brucella LPS buildup of N-formyl-d-perosamine units, connected via α-(1→3)-linkage at the non-reducing end and α-(1→2)-linkage at the reducing end. The sensitivity and specificity in the case of the use of trisaccharide tracer 3b were 71% and 100% (Yuden's method) and 87% and 88% (Euclidean method), respectively, which is comparable with the diagnostic efficiency of traditionally used serological methods, such as the agglutination test (AT), complement fixation test (CFT), and Rose Bengal test (RBT). Given the known advantages of FPA (e.g., speed, compactness of the equipment, and standard reagents) and the increased specificity of the developed test system, it would be appropriate to consider its widespread use for the diagnosis of brucellosis in animals, including rapid testing in the field.

Antibody mechanisms of protection against malaria in RTS,S-vaccinated children: a post-hoc serological analysis of phase 2 trial

The RTS,S malaria vaccine is currently recommended for children aged 5-6months in regions with moderate-to-high Plasmodium falciparum transmission. However, vaccination only confers 55% efficacy over 12months and wanes within 18months. The immunological mechanisms of RTS,S-mediated immunity are poorly understood; therefore, we aimed to identify antibody response types associated with protection against malaria in children vaccinated with RTS,S. In this post-hoc analysis, we evaluated antibody responses in 737children aged 1-4 years vaccinated with RTS,S in a phase 2b clinical trial conducted in Mozambique in 2003. We evaluated all available samples collected from children 30days after the three-dose vaccination schedule at study month 3 (M3; n=737available of 803children allocated to receive RTS,S). For comparison, we tested a subset of samples collected before vaccination at study month 0 (M0; n=50) and from children in the control vaccine group (M0 n=25; M3 n=99). We quantified the induction of antibodies to different regions of the vaccine antigen that function by fixing serum complement proteins and binding to Fcγ receptors (FcγRs; FcγRI, FcγRIIa, and FcγRIII) expressed on immune cells as potential mechanisms of immunity. Functional antibody responses to the C-terminal region of the vaccine antigen, circumsporozoite protein (CSP), were associated with a reduced risk of malaria (C1q p=0·0060, FcγRIIa p=0·014, and FcγRIII p=0·019). These associations remained significant in male participants when the analyses were stratified by sex (C1q p=0·012, FcγRIp=0·023, FcγRIIa p=0·0070, and FcγRIII p=0·0080). IgA to the central repeat (p=0·0010) and C-terminal (p=0·0040) regions of CSP were also associated with protection. We show that IgA can bind FcαRI and mediate opsonic phagocytosis using a serum pool and monoclonal antibodies. Multiparameter analysis using machine-learning methods suggest that IgA, complement fixation, and FcγRI binding were most predictive of protection against malaria (hazard ratio <1) and suggested that associations differed between male and female participants. We provide evidence that functional antibody responses mediated by IgG and IgA are associated with protection against malaria in young children vaccinated with RTS,S, and suggest potential differences in the correlates of immunity between males and females. These findings reveal new avenues that could be used to achieve malaria vaccines with higher efficacy. National Health and Medical Research Council, Australia, and Thrasher Research Fund.

The epizootic situation of bovine paratuberculosis in Ukraine for the period 2019–2023

Paratuberculosis (Johne’s disease) is a contagious infectious disease, the etiological agent of which affects various species of mammals, mainly ruminants. The causative agent is the acid-resistant bacterium Mycobacterium avium subsp. paratuberculosis (MAP), which belongs to the family Mycobacteriaceae. The most sensitive to it are domestic ruminants (cattle, sheep, goats etc.), which are the main reservoirs of infection for the various species of animals and humans (the zoonotic potential of the pathogen requires further study). In Ukraine, the main methods for diagnosing paratuberculosis are serological and bacteriological techniques. The authors analyzed the epizootic situation of paratuberculosis among cattle in Ukraine during 2019–2023 by systematizing the data of their own research and official reports of state veterinary laboratories in regions. The results of the investigation are presented without taking into account the temporarily occupied territories of Luhansk and Donetsk oblasts and the Autonomous Republic of Crimea, as well as part of the territory where military operations were conducted. In total, over the five-year period, 41 679 samples were examined serologically in the complement fixation test and 13 405 – bacteriologically, by microscopy and cultivation of biological materials on the nutrient media. During the investigation, specific antibodies to the pathogen were detected in 36 samples (prevalence, about 0.1%; BCI, 0.06–0.12%) from the ten regions. The analysis of the serological studies shows that the disease is sporadic and has a significant downward trend in the number of positive cases (17 positive samples were detected in 2019 and 2020, and only two in 2023). As for bacteriological examination, no positive cases have been registered during the 5-year period. In addition to the scrupulous work of the veterinary medicine service, both the persistent decrease in the cattle population and the ongoing hostilities in Ukraine have a considerable impact on improving the epizootic situation., as the number of serological tests conducted after 2022 has almost halved (especially in the eastern and southern regions), and bacteriological tests have decreased fivefold. The visualization of the data shows that antibodies were mostly detected in animals from the central, eastern, northern, and northwestern regions of the country.

Three dermatologists who were nominated for a Nobel Prize: Albert Neisser, Erich Hoffmann, and Aaron B. Lerner

During the past 125 years, three dermatologists have been nominated for the Nobel Prize in Physiology or Medicine: Albert Neisser (1855-1916), Erich Hoffmann (1868-1959), and Aaron B. Lerner (1920-2007). Neisser was nominated 22 times for his discovery of the gonococcus and for his work on the serologic testing for syphilis through complement fixation. Hoffmann was nominated three times for his role in the discovery of Treponema pallidum. Lerner was nominated twice, once for his work on melanocyte-stimulating hormone and a second time for his work on melatonin. Although neither Neisser, Hoffmann, nor Lerner won the Nobel Prize, it is still a notable accomplishment that each of them was nominated multiple times for this prestigious award. This contribution highlights the lives and careers of these three distinguished dermatologists, including the landmark discoveries they made that led to their being nominated for a Nobel Prize.As of 2023, there were 114 Nobel Prizes in Physiology or Medicine awarded to 227 individuals, none of whom were dermatologists. There were, however, three distinguished dermatologists who were nominated for this illustrious prize: Albert Neisser (1855-1916), Erich Hoffmann (1868-1959), and Aaron Bunsen Lerner (1920-2007) (Figures 1-3). Although these three dermatologists failed to win the Nobel Prize, it remains a signal accomplishment for each of them to have been nominated for such a prestigious award on multiple occasions in recognition of their outstanding discoveries that have had a significant impact on modern-day medicine. This Fun Facts About Dermatology presentation highlights the lives and careers of Neisser, Hoffmann, and Lerner and the important scientific contributions that led to their nominations for medicine's most coveted award: the Nobel Prize.

Testing for Blastomycosis, Coccidioidomycosis, and Histoplasmosis at a Major Commercial Laboratory, United States, 2019-2024.

Blastomycosis, coccidioidomycosis, and histoplasmosis are environmentally acquired fungal diseases that clinically resemble bacterial and viral community-acquired pneumonia and require laboratory testing for diagnosis. Patients frequently present to primary care and experience diagnostic delays when a fungal etiology is not initially suspected. Current national-level public health surveillance for these diseases is limited and does not include laboratory data, so nationwide testing practices are unknown. We identified laboratory tests for blastomycosis, coccidioidomycosis, and histoplasmosis ordered during 1 March 2019-29 February 2024 and performed within a major national commercial laboratory system. We analyzed test results, patient and healthcare provider features, reasons for testing, and temporal trends. Results included 5693 Blastomyces complement fixation tests (of those, 12% were positive), 71 858 immunodiffusion tests (0.1% positive), and 1186 serum enzyme immunoassay (EIA) tests (11% positive); 154 989 Coccidioides EIA immunoglobulin M results (5% positive) and 154 968 immunoglobulin G results (8% positive); and 46 346 Histoplasma complement fixation tests (30% positive), 49 062 immunodiffusion tests (1% positive), 35 506 serum EIA tests (4% positive), and 82 489 urine EIA tests (2% positive). Most histoplasmosis (58%-74%) and blastomycosis (42%-68%) tests were ordered from hospitals, whereas coccidioidomycosis tests were most frequently ordered by primary care providers (40%). A yearly average of 2727 positive tests were ordered by healthcare providers in states without public health surveillance for these diseases. Blastomycosis, coccidioidomycosis, and histoplasmosis are likely underdetected in primary care settings or by public health surveillance. Increased testing by primary care providers and expanded surveillance are needed to reduce disease burden.

Characteristics of Early Antibody Mediated Rejection in Antibody Incompatible Living Donor Kidney Transplantation.

Antibody incompatible transplantation (AIT) may be an only option for highly sensitized patients. Severe form of early antibody mediated rejection (AMR) adversely affects graft survival after AIT. The aim of this study was to identify individuals at risk of AMR. We analyzed 213 living donor AITs performed at our center. Among 120 ABOi, 58 HLAi and 35 DSA + FCXM-negative cases, the rates of early AMR were 6%, 31%, and 9%, respectively (p < 0.001). On multivariate analysis for graft loss, early AMR had a HR of 3.28 (p < 0.001). The HLAi group had worse death-censored graft survival (p = 0.003). In the HLAi group, Patients with aggressive variant AMR (AAMR) had greater percentage of C3d complement fixing DSA, higher baseline class I and total DSA MFI levels and B-cell FCXM RMF. C1q and C3d complement fixing DSA and strong positivity of baseline B- or T-cell FXCM as predictors of AAMR had 100% sensitivity. Early AMR is of significant clinical concern in AIT as it results in poor graft survival and is not well described in literature. An aggressive variant is characterized by massive rise in DSA levels at rejection. Baseline DSA, C1q, and C3d and baseline FCXM values can be used to risk-stratify candidates for AIT.

Development and Bayesian validation of a competitive inhibition ELISA for detection of antibodies against Brucella abortus in cattle

Bovine brucellosis is a zoonotic disease caused by Brucella abortus, responsible for abortions in cows. It is endemic in low- and middle-income countries, where the brucellosis control and eradication programs are based on compulsory vaccination, detection of infected cattle through serologic assays, and culling of infected animals at slaughterhouses. The development of high sensitivity and specificity, and low-cost serologic assays guarantee their implementation in countries where the disease is endemic. The aim of the present study was to develop and validate a competitive inhibition enzyme-linked immune assay (ciELISA) to detect anti-B. abortus antibodies in sera from cattle. The developed ciELISA was validated using 2833 serum samples from dairy and beef cattle. From these, 1515 sera were from uninfected cows that belonged to free of brucellosis herds and 1318 were from infected cows that belonged positive to brucellosis herds. Sera were analyzed with the developed ciELISA, the buffer plate antigen (BPA) test, and the complement fixation test (CFT). The brucellosis status of the herds was officially established according to the country legislation and consistent for at least 5 years and was defined for each cow using the CFT as gold standard. The cutoff for the ciELISA was calculated using a ROC curve and its sensitivity and specificity were analyzed using the Bayesian Latent Class Model (BLCM) approach. The agreement among tests was calculated using the kappa (κ) value. In addition, 15 calves were vaccinated with 3 × 1010 viable cells of B. abortus Strain 19 vaccine, and the dynamics of antibodies were measured by CFT, buffered plate antigen (BPA) test, and the developed ciELISA. The obtained cutoff for ciELISA was ≥ 47 percentage of inhibition (% I), at the BLCM approach the sensitivity was 99.01 % (95 % CI: 97.55–100) and the specificity 98.74 % (95 % CI: 97.68–99.8). The κ between the ciELISA and BPA was κ = 0.88 and between the ciELISA and CFT κ = 0.95. Antibodies against B. abortus were detected in all the vaccinated calves 7 days after vaccination (AV) by the three assays, at day 135 AV all the calves were negative to CFT (15/15), 93.3 % (14/15) to ciELISA and 73.3 % (11/15) to BPA, and at day 190 AV all the calves were negative to the three assays. The developed ciELISA showed a very good performance, could detect the majority of vaccinated animals as negative after 135 days and could be used for the detection of anti-B. abortus antibodies in serum samples for the brucellosis control and eradication program.

Diagnosis of Coccidioidomycosis with the Second-Generation Miravista IgG and IgM Enzyme Immunoassay and the Role of Adding Miravista Coccidioides Antigen Detection to Immunodiagnostic Assays.

In the present study, we validate and compare the second-generation Miravista Coccidioides IgG and IgM enzyme immunoassays (EIA) (MiraVista Diagnostics [MVD] Ab EIA) to Meridian Diagnostics Coccidioides IgG and IgM EIA (Meridian Ab EIA), immunodiffusion (ID) and complement fixation (CF). We also evaluated whether the addition of Coccidioides antigen testing to anti-Coccidioides antibody testing increased the sensitivity for the diagnosis of currently active coccidioidomycosis. We retrospectively studied 555 patients evaluated at Valleywise Health Medical Center between January 2013 and May 2017 for whom coccidioidomycosis was suspected and samples were submitted to MVD for testing. Specimens were tested for antigen in the MVD antigen enzyme immunoassay (MVD Ag EIA) and for IgG and IgM antibodies with MVD and Meridian Diagnostics EIAs. ID and CF were obtained from medical records. Sensitivity and specificity were 83.0% and 91.1% or MVD Ab EIA, 69.3% and 99.7% for Meridian Ab EIA, 85.4% and 100% for ID and 65.5% and 100% for CF. Combined MVD antigen and antibody detection by EIA and ID resulted in increased sensitivity in disseminated and pulmonary disease (MVD Ag/MVD Ab: 100%, 88.3%; MVD Ag/Meridian Ab: 98.2%, 78.6%; and MVD Ag/ID: 100%, 91.7%). The detection of antibodies by MVD EIA was more sensitive than Meridian EIA or CF but similar to ID. This study supports the use of antigen testing in immunocompromised patients and those with suspected disseminated disease. Furthermore, the addition of antigen detection by EIA to antibody detection resulted in higher sensitivity of all serological tests.

Sero-epidemiological study of brucellosis in cattle under pastoral/agro-pastoral and mixed crop-livestock systems in South Omo, southern Ethiopia

BackgroundIn the pastoral/agro-pastoral communities in Ethiopia, like in South Omo, brucellosis constitutes a serious health threat for livestock and the public. The public health risk is especially high in these communities, as their way of life is highly linked with their herds. ObjectiveThe study was conducted to estimate the seroprevalence and identify potential risk factors of cattle brucellosis in South Omo zone in southern Ethiopia. MethodsA total of 614 traditionally managed local zebu female cattle, above six months old, were bled and data on hypothesized risk factors were collected using a semi-structured questionnaire. The preliminary screening of the sera for Brucella antibodies was done using Rose Bengal Plate Test (RBPT) and positive sera were further subjected to complement fixation test (CFT). ResultsThe overall animal level seroprevalence of brucellosis was 2.8 % (95 % CI: 1.72–4.41) while herd level prevalence was 11.3 % (95 % CI: 6.5–19.0). Among the risk factors considered, seroprevalence was associated with herd size, new animal introduction, district, history of occurrence of abortion, and retained fetal membranes (RFM), at both individual- and herd-level (p < 0.05). Higher seroprevalence of brucellosis was observed in cows than heifers and in animals older than 4 years (p < 0.05). Brucella seroprevalence was higher in herds in lowland areas than those in mid-altitude and highlands (p < 0.05). ConclusionThe individual and herd level prevalence observed in our study indicates endemicity of brucellosis and the potential public health threat it poses in pastoral and agro-pastoral areas of southern Ethiopia. The results of the study also suggest that the disease might be responsible for significant losses in cattle productivity due to impaired reproductive performance.

Full-length MSP1 is a major target of protective immunity after controlled human malaria infection.

The merozoite surface protein 1 (MSP1) is the most abundant protein on the surface of the invasive merozoite stages of Plasmodium falciparum and has long been considered a key target of protective immunity. We used samples from a single controlled human malaria challenge study to test whether the full-length version of MSP1 (MSP1FL) induced antibodies that mediated Fc-IgG functional activity in five independent assays. We found that anti-MSP1FL antibodies induced complement fixation via C1q, monocyte-mediated phagocytosis, neutrophil respiratory burst, and natural killer cell degranulation as well as IFNγ production. Activity in each of these assays was strongly associated with protection. The breadth of MSP1-specific Fc-mediated effector functions was more strongly associated with protection than the individual measures and closely mirrored what we have previously reported using the same assays against merozoites. Our findings suggest that MSP1FL is an important target of functional antibodies that contribute to a protective immune response against malaria.

Discovery of a Unique Set of Dog-Seroreactive Coccidioides Proteins Using Nucleic Acid Programmable Protein Array.

Valley Fever (VF), caused by fungi in the genus Coccidioides, is a prevalent disease in southwestern and western parts of the United States that affects both humans and animals, such as dogs. Although the immune responses to infection with Coccidioides spp. are not fully characterized, antibody-detection assays are used in conjunction with clinical presentation and radiologic findings to aid in the diagnosis of VF. These assays often use Complement Fixation (CF) and Tube Precipitin (TP) antigens as the main targets of IgG and IgM reactivity, respectively. Our group previously reported evidence of over 800 genes expressed at the protein level in C. posadasii. However, antibody reactivity to the majority of these proteins has never been explored. Using a new, high-throughput screening technology, the Nucleic Acid Programmable Protein Array (NAPPA), we screened serum specimens from dogs against 708 of these previously identified proteins for IgG reactivity. Serum from three separate groups of dogs was analyzed and revealed a small panel of proteins to be further characterized for immuno-reactivity. In addition to CF/CTS1 antigen, sera from most infected dogs showed antibody reactivity to endo-1,3-betaglucanase, peroxisomal matrix protein, and another novel reactive protein, CPSG_05795. These antigens may provide additional targets to aid in antibody-based diagnostics.

Indirect hemagglutination assay for diagnosing brucellosis: Past, present, and future

Brucellosis is a zoonotic disease that causes enormous losses in livestock production worldwide and has a significant public health impact. None of the brucellosis-free countries is currently able to guarantee their ability to prevent the introduction of the pathogen due to the increase in tourism and the expansion of migration. The timely identification of infected animals is an effective means of preventing brucellosis and minimizing the epidemiological risk. The tube agglutination test, Rose Bengal plate test, complement fixation test, and enzyme-linked immunosorbent assay, which are routinely used to identify seropositive productive animals, have limitations and results that do not always correlate. The indirect hemagglutination assay (IHA) stands out among non-traditional methods because it is affordable, has a simple protocol, and is more reliable than classical serological tests, especially in cases of questionable and/or false-negative results. The diagnostic value of the IHA has long been studied by laboratories in several countries, but mostly by post-soviet research teams; therefore, the results continue to be published in Russian-language journals, ensuring that the local scientific community can access the results. In addition, the efficacy of this test for the diagnosis of brucellosis and other infectious diseases has not yet been reviewed. The purpose of this review was to summarize the results of studies on the development and use of IHA for the diagnosis of brucellosis and to determine the prospects for further improvement Keywords: brucellosis, diagnostic value, indirect hemagglutination assay, prospects for improving the test, serological tests.

A Review on Paragonimiasis and its Differential Diagnosis Technique

This review highlights the existence of Paragonimus (PRG) and how they are mistaken for Tuberculosis (TB) during diagnosis. PRG is a parasitic lung fluke (flatworm) that infect the lungs, human serves as the first hosts, crabs, crayfish, and snails as the second intermediate hosts. The north-eastern states of India are endemic to PRG and infection is acquired by consuming uncooked or partially cooked crustaceans. Due to their similar clinical presentation to TB, PRGs are usually misdiagnosed, leading to delayed treatment. Ziehl-Neelsen (ZN) stain, conventional wet film for staining the sputum, pleural fluid, and stool, and lung biopsy are different laboratory tests to determine PRG infection. In addition, efficient technique that can aid diagnosis are immunological assays, like Enzyme-linked immunosorbent assay (ELISA), dot-ELISA, complement fixation test (CFT), intradermal test (ID), Western blot, immunodiffusion and indirect haemagglutination test (IHA). In India, PRG infection is most likely to persist until medical professionals and governing bodies raise awareness to implement adequate management measures.

USING INDIRECT HEMAGGLUTINATION ASSAY FOR THE DIAGNOSIS OF CATTLE BRUCELLOSIS

Abstract: The possibility of using indirect hemagglutination assay (IHA) with milk (IHA/m) to differentiate post-infectious antibodies from post-vaccination ones in cows immunized with the Brucella abortus 82 was studied. Anti-Brucella antibodies by IHA/m were detected in the milk of all lactating animals (n=20) culled on the results of tube agglutination test (AT) and/or complement fixation test (CFT), while the milk ring test (MRT) were negative in 20% of cases. IHA/m, as well as IHA with blood serum (IHA/s), confirmed brucellosis in cows with AT- and/or CFT- negative or questionable results. The correlation coefficient between the results of the two IHA variants was very high (r = 793), and the hemagglutinin titers in the blood serum were significantly higher - 1:760 (+13.3%; -11.7%) than in AT-1:260 (+8.7%;-8.0%) (P≤0.01). Vaccination of cows caused increased production of complement-fixing, agglutinating and precipitating antibodies, which tended to weaken during observation of the animals: 30, 60 and 90 days post-vaccination (p.v.). By the end of the experiment, all vaccinated animals showed questionable AT; positive RID/O-PS and IHA/s were noted in 10% and 20% of cases, respectively. However, complement-fixing antibodies remained at diagnostic values in all animals until the end of the experiment. Despite the intense antibody immune response to the vaccine injection, there were no Brucella-specific agglutinins detected by IHA/m and MRT in the milk of cows even on the 30th day p.v. The results show the need for further study on a large population to determine the diagnostic value of IHA/m for differentiating infected from vaccinated animals.&#x0D;

Development and validation of a chemiluminescent western blot assay for glanders (Burkholderia mallei) serodetection.

Glanders, caused by Burkholderia mallei, is a zoonotic disease of equids. Serologic testing for glanders is required by disease-free countries before international movement of equids. The World Organisation for Animal Health Terrestrial Manual recommends the complement fixation test (CFT) for clearance of individual animals for movement, but the CFT is prone to false-positive results. A colorimetric western blot (WB) assay was developed and validated to resolve false-positive CFT results; however, that assay is relatively time-consuming, and the interpretation is subjective. We present here a procedurally similar chemiluminescent WB assay that performs comparably to the validated colorimetric WB assay and offers noticeable benefits of decreased time-to-result and greater ease of interpretation.

Etiological diagnostic methods and research progress of forest encephalitis

Forest encephalitis is a natural focal disease transmitted through the bite of hard ticks, and its pathogen is the tick-borne encephalitis virus from the Flaviviridae family. The mortality rate of forest encephalitis is relatively high, making laboratory testing significant in diagnosing this disease. This article elaborates on the etiological diagnostic methods and recent research progress in forest encephalitis. Laboratory tests for forest encephalitis mainly include routine examinations, serological tests, virus isolation, and molecular biological testing. The detection of serum-specific IgM antibodies against the forest encephalitis virus is of great importance for early diagnosis, and specific IgG antibodies serve as a "gold standard" for differentiation from other diseases. Techniques such as enzyme-linked immunosorbent assay (ELISA) or indirect immunofluorescence assay for detecting specific IgM antibodies in serum and/or cerebrospinal fluid, the serum hemagglutination inhibition test or serum complement fixation test, and the double serum hemagglutination inhibition test or complement fixation test all contribute to the early diagnosis. The development of molecular testing methods is rapid, and techniques such as metabolomics, digital PCR, and matrix metalloproteinases are also applied in the early diagnosis of forest encephalitis.

Seasonal Testing, Results, and Effect of the Pandemic on Coxsackievirus Serum Studies.

Coxsackieviruses (CVs) are common causes of infections and can be life-threatening. Unfortunately, rigorous studies guiding the clinician in interpreting CV serum antibody titer testing is lacking. To explore the epidemiology of circulating CVs and the serological test utility in aiding diagnosis of CV infections in our community, we obtained results of CV immunologic diagnostic tests between 2018 and 2022 from a regional healthcare database. For CV type A, rare individuals had positive CF (complement fixation) tests whereas all 16 individuals with IFA testing showed at least one positive serotype. For CV type B CF testing, 52.2% of 222 patients had at least one serotype positive, with B5 being most common and also the most common with higher titers (14.8% with ≥1:32). We found a significant reduction in seropositivity rate during the pandemic in 2020 compared to 2018, which continued through 2022 (OR: 0.2, 95% CI: 0.08-0.49, p-value < 0.001). During the pandemic, the seasonal pattern of positive tests varied from the pre-pandemic pattern. Testing for CVs was increased after the first year of the pandemic. Overall, the variability by month and seasonal change in our data support that CF testing can be used to identify recent CVB infection.