Porcine Brucellosis Research Articles

Histopathologic and immunohistochemical findings in the placentas and fetuses of domestic swine naturally infected with Brucella suis biovar 2.

Porcine brucellosis, which is caused by Brucella suis biovar (bv) 2, is a re-emerging disease that causes reproductive problems in pigs in Europe. The pathogenesis and lesions of B. suis intrauterine infection are poorly characterized; characterization could facilitate the diagnosis and investigation of porcine brucellosis. We collected samples of placentas and fetuses for histologic and microbiologic studies during an outbreak of abortions on a pig-breeding farm in Spain. Brucella was cultured from the vaginal swabs obtained from sows that had aborted, some placentas, and fetal tissues (spleen, liver, lung, gastric content); molecular testing confirmed B. suis bv 2 infection. Histologically, there was necrotizing and hemorrhagic placentitis; suppurative hepatitis; lymphoid depletion and sinusoidal histiocytosis in the spleen, lymph nodes, and thymus; and bronchointerstitial pneumonia. Hemorrhages were observed in the umbilical cord, heart, kidneys, and brain. We detected Brucella by immunohistochemistry (IHC) in all of the placentas and fetal organs studied, specifically in the trophoblasts of the chorionic epithelium, in the cytoplasm of macrophages in the chorionic stroma, and extracellularly in necrotic debris. Furthermore, we assessed the lymphocyte population in the placentas through the use of IHC (anti-CD3, anti-Pax5 antibodies), revealing that the lymphocytic response was composed of T cells but not B cells.

Seroprevalence of Brucella Infection in Wild Boars (Sus scrofa) of Bavaria, Germany, 2019 to 2021 and Associated Genome Analysis of Five B. suis Biovar 2 Isolates

Brucella species are highly pathogenic zoonotic agents and are found in vertebrates all over the world. To date, Germany is officially declared free from brucellosis and continuous surveillance is currently limited to farm ruminants. However, porcine brucellosis, mostly caused by B. suis biovar 2, is still found in wild boars and hares. In the present study, a three-year monitoring program was conducted focusing on the wild boar population in the state of Bavaria. Serologic screening of 11,956 animals and a direct pathogen detection approach, including a subset of 681 tissue samples, was carried out. The serologic incidence was 17.9%, which is in approximate accordance with previously published results from various European countries. Applying comparative whole genome analysis, five isolated B. suis biovar 2 strains from Bavaria could be assigned to three known European genetic lineages. One isolate was closely related to another strain recovered in Germany in 2006. Concluding, porcine brucellosis is endemic in Bavaria and the wild boar population represents a reservoir for genetically distinct B. suis biovar 2 strains. However, the transmission risk of swine brucellosis to humans and farm animals is still regarded as minor due to low zoonotic potential, awareness, and biosafety measures.

Monoclonal Antibody based Blocking ELISA for Diagnosis of Brucellosis

Background: Porcine brucellosis is a contagious and emerging zoonosis but neglected in most of the endemic countries including India. The disease in pigs is rarely reported due to non-availability of diagnostics or major focus is on bovine brucellosis. Hence, the necessity was felt to diagnose porcine brucellosis by Monoclonal antibody based ELISA, RBPT and STATS for the detection of anti-Brucella antibodies and to record spatial seroprevalence of porcine brucellosis in the country. Methods: The Rose Bengal Plate Test (RBPT), Standard tube agglutination test (STAT) and Bru Alert monoclonal antibody based c-ELISA was employed to screen 148 sera samples for the presence of Brucella antibody. Result: A total 148 samples were collected and tested, the overall prevalence of Brucella infection in pig was 43.2% per cent (64/148) by C-ELISA followed by RBPT 40% (60/148) and STAT 25% (40/148) in the study area comparatively high seropositivity was found in female animals. The agreement between the two test was excellent (Kappa = 0.167) and also, chisquare test indicated an evidence of strong diagnostic weapon for detection of swine brucellosis.

Environment and Offspring Surveillance in Porcine Brucellosis.

Porcine brucellosis, caused by Brucella suis (B. suis), is a notifiable disease causing significant economic losses in production systems. Most infected pigs may act as carriers and shed B. suis even if asymptomatic. This can contribute to environmental persistence, thus hindering control efforts. Here, the environment and the offspring were investigated during and after a B. suis outbreak at a sow breeding farm. The diagnosis of B. suis in sows (n = 1,140) was performed by culture and polymerase chain reaction (PCR) from vaginal swabs, indirect enzyme-linked immunosorbent assay (I-ELISA) from sera, and brucellin skin test (BST). B. suis diagnosis in post-weaning pigs (n = 899) was performed by I-ELISA in sera and BST. The environmental surveillance programme was implemented by placing gauze sponges (n = 175) pre-hydrated in a surfactant and inactivating liquid for Brucella DNA detection by PCR in different farm areas. Our results showed that the offspring of infected sows reacted to in vivo techniques for B. suis. Furthermore, the offspring born during the outbreak displayed higher seropositivity (I-ELISA) and reactivity (BST) than those pigs born after. Brucella DNA was detected in pregnant sow areas, boxes, boots, and post-weaning pig areas. In addition, Brucella DNA environmental detection was higher during the B. suis outbreak than the post B. suis outbreak. The environmental approach has proven to be a simple, practical, valuable, and safe method to detect and monitor B. suis. These results suggest a role of the environment and the offspring that should be considered in porcine brucellosis surveillance and control programmes.

Selected Endemic Zoonoses in Pigs Presenting for Slaughter in Kampala, Uganda.

.Leptospirosis, brucellosis, and Q fever (coxiellosis) are bacterial zoonoses that cause acute febrile illness in people as well as reproductive losses in pigs. Pig keeping is an increasingly important livelihood to millions of smallholder farmers in Uganda because of exponential increases in demand for pork. The prevalence of leptospirosis and Q fever in pigs is unknown, and the few studies of porcine brucellosis have estimated a range of seroprevalence. Therefore, we undertook a prevalence survey of leptospirosis, brucellosis, and Q fever in pigs using quantitative real-time PCR to determine the potential importance of these zoonoses to the growing pig sector in Uganda. Six hundred forty-nine pigs were sampled in 2015–2016 at an urban pork slaughterhouse. Ten percent of pigs (n = 68) had leptospiral DNA in either their kidney or reproductive tissue. In adjusted analyses, variables predictive of leptospiral status included female sex (odds ratio [OR]: 2.37, P < 0.01) and pigs sampled in March 2016 (OR: 2.23, P = 0.02) and October 2016 (OR: 0.30, P = 0.04). DNA fingerprinting revealed circulation of at least four distinct serovars in these pigs. Brucella spp. and Coxiella burnetii DNA were not detected in any sampled pig. This is the first report of widespread circulation of pathogenic Leptospira spp. in pigs in Uganda, suggesting that leptospirosis likely has a greater impact on the health of pigs than was previously recognized. Pig farmers, pig traders, and slaughterhouse workers may be at greatest occupational risk because of their direct contact with infective leptospires in aborted fetuses, bodily fluids, and other tissues.

Seroepidemiological survey of brucellosis and isolation of Brucella suis from swine herds of Meghalaya, North-East India

Brucellosis is a well-known and wide spread zoonotic disease. It is endemic in several parts of Asia, including India. In this study, seroprevalence of porcine brucellosis was studied among apparently healthy pigs in Meghalaya where pig keeping plays a significant function in socio-economic development. Serum samples (3,597) from pigs were screened using Rose Bengal Plate Test (RBPT) and indirect ELISA. Isolation of Brucella was attempted in clinical samples. A total of 13 (0.36%) were positive by RBPT and 72(2%) by Indirect ELISA. Brucella suis isolate was recovered from placenta of an aborted pig. Risk factors involved in the transmission of brucellosis amongst swine herd were studied. It was observed that age (OR=0.590; P=0.04) and sex (OR=0.557; P=0.04) were significant intrinsic risk factors for transmission of porcine brucellosis. Although the seroprevalence is low, isolation of B. suis from an aborted pig indicated that disease is actively circulating among swine herds of Meghalaya.

Fluorescence polarization assay: Diagnostic evaluation for porcine brucellosis

Brucellosis in pigs, caused by the bacterium Brucella suis, is an important zoonotic infection. In the present study, fluorescence polarization assay (FPA) was standardized and compared with indirect enzyme linked immunosorbent assay (iELISA) and competitive ELISA (cELISA) for diagnosis of porcine brucellosis. Test performances were evaluated using representative panel (n = 100), samples from swine brucellosis outbreak (n = 300), samples from brucellosis suspected animals (n = 291) and sera samples from apparently healthy animals (n = 1121). With panel samples, the FPA cut-off ≥11ΔmP was arrived with sensitivity (Se) and specificity (Sp) of 95.00 and 98.75%, respectively. Testing of samples from swine brucellosis outbreak, the diagnostic Se and Sp of 100 and 95.14% by iELISA, 73.91 and 100% by cELISA and 86.96 and 100% by FPA, respectively were recorded. Similarly, in case of swine brucellosis suspected samples, relative performance of FPA with cELISA had revealed higher kappa value of 0.864 with an accuracy of 93.47. Indirect ELISA was found to be highly sensitive but showed cross reactivity mainly for Yersinia enterocolitica O9 antibodies than cELISA and FPA. The high specificity of FPA test recorded in various types of samples in the study indicated that, FPA could serve as confirmatory test for individual animal diagnosis, outbreak confirmation, surveillance and quarantine of swine brucellosis cases.

Brucella suis biovar 2 multi locus sequence type ST16 in wild boars (Sus scrofa) from Abruzzi region, Italy. Introduction from Central-Eastern Europe?

Porcine brucellosis occurs in many countries where pigs are farmed, often representing an underrated problem. B. suis biovar 2 is the most common isolate in Europe, with high prevalence reported in wild boars in which it is generally isolated in the absence of gross lesions. In the last five years, we tested for Brucella spp. 389 lymph nodes of wild boars collected during hunting seasons or during necropsy procedures.In this paper, we describe the first case of isolation of B. suis biovar 2 from a wild boar aborted foetus, and we analyse the genomic relationships with B.suis biovar 2 strains isolated in the past five years in Abruzzi Region, Central Italy. The genetic fingerprint revealed that the isolates under study belong to the MLST ST16 and to the MLVA11 Gt 57, similar to the Central-Eastern European strains. Massive restocking (for hunting purpose) of wild boars from Eastern Europe have been done since 1950 in Italy contributing to the increasing of population size and distribution, as well as to the interbreeding between these foreign breeds and the local population. The contamination of pastures with infected material such as aborted wild boars foetuses can increase the risk of transmission of Brucella among wild and domestic animals. The contact of B. suis with domestic ruminants may also cause serological reactions to brucellosis serological testing, and even unapparent infection, thus hampering the efforts made in the brucellosis eradication campaign.

Record of porcine brucellosis in India by indigenously developed indirect ELISA

Porcine brucellosis is a contagious and emerging zoonosis but neglected in most of the endemic countries including India. The disease in pigs is rarely reported due to non-availability of diagnostics or major focus is on bovine brucellosis. Hence, the necessity was felt to develop indirect ELISA for the detection of anti-Brucella antibodies and to record spatial seroprevalence of porcine brucellosis in the country. The relative diagnostic sensitivity and specificity of the developed indirect ELISA were 94.0% and 92.0%, respectively and kappa agreement with rose bengal plate test, serum agglutination test and commercial indirect ELISA kit was found to be 0.86 (95% confidence interval 0.78–0.93). A total of 2 576 random serum samples sourced from 10 states were screened by indirect ELISA and true prevalence of 7.2% (95% confidence interval 5.6–8.7) was recorded. The study concluded the prevalence of brucellosis in swine population in many states of the country and indirect ELISA as an alternate test to rose bengal plate test and serum agglutination tests.

A genome-wide SNP-based phylogenetic analysis distinguishes different biovars of Brucella suis

Brucellosis is an important zoonotic disease caused by Brucella spp. Brucella suis is the etiological agent of porcine brucellosis. B. suis is the most genetically diverged species within the genus Brucella. We present the first large-scale B. suis phylogenetic analysis based on an alignment-free k-mer approach of gathering polymorphic sites from whole genome sequences. Genome-wide core-SNP based phylogenetic tree clearly differentiated and discriminated the B. suis biovars and the vaccine strain into different clades. A total of 16,756 SNPs were identified from the genome sequences of 54 B. suis strains. Also, biovar-specific SNPs were identified. The vaccine strain B. suis S2–30 is extensively used in China, which was discriminated from all biovars with the accumulation of the highest number of SNPs. We have also identified the SNPs between B. suis vaccine strain S2–30 and its closest homolog, B. suis biovar 513UK. The highest number of mutations (22) was observed in the phosphomannomutase (pmm) gene essential for the synthesis of O-antigen. Also, mutations were identified in several virulent genes including genes coding for type IV secretion system and the effector proteins, which could be responsible for the attenuated virulence of B. suis S2–30.

A Bacterial Glycoengineered Antigen for Improved Serodiagnosis of Porcine Brucellosis.

Brucellosis is a highly zoonotic disease that affects animals and human beings. Brucella suis is the etiological agent of porcine brucellosis and one of the major human brucellosis pathogens. Laboratory diagnosis of porcine brucellosis mainly relies on serological tests, and it has been widely demonstrated that serological assays based on the detection of anti O-polysaccharide antibodies are the most sensitive tests. Here, we validate a recombinant glycoprotein antigen, an N-formylperosamine O-polysaccharide-protein conjugate (OAg-AcrA), for diagnosis of porcine brucellosis. An indirect immunoassay based on the detection of anti-O-polysaccharide IgG antibodies was developed coupling OAg-AcrA to enzyme-linked immunosorbent assay plates (glyco-iELISA). To validate the assay, 563 serum samples obtained from experimentally infected and immunized pigs, as well as animals naturally infected with B. suis biovar 1 or 2, were tested. A receiver operating characteristic (ROC) analysis was performed, and based on this analysis, the optimum cutoff value was 0.56 (relative reactivity), which resulted in a diagnostic sensitivity and specificity of 100% and 99.7%, respectively. A cutoff value of 0.78 resulted in a test sensitivity of 98.4% and a test specificity of 100%. Overall, our results demonstrate that the glyco-iELISA is highly accurate for diagnosis of porcine brucellosis, improving the diagnostic performance of current serological tests. The recombinant glycoprotein OAg-AcrA can be produced in large homogeneous batches in a standardized way, making it an ideal candidate for further validation as a universal antigen for diagnosis of "smooth" brucellosis in animals and humans.

Characterisation of Brucella suis isolates from Southeast Europe by multi-locus variable-number tandem repeat analysis

Porcine brucellosis is a common bacterial zoonosis which can cause significant financial losses. Its diverse and often complicated factors have hampered efforts to control disease spread.The aim of the study was to assess the epidemiological situation of porcine brucellosis primarily in Croatia and its relationship to genotypes present in other, mostly European countries. One hundred and seven Brucella suis strains isolated from swine, hares, cattle, humans, wild hares, a wild boar and a mare originating mainly from Croatia (112), but also a few from Slovenia, Bosnia and Herzegovina, Serbia and Macedonia (15) were tested using classical microbiological testing, Bruce-ladder, RFLP, Multiplex-suis and genotyped using multi-locus variable-number tandem repeat analysis (MLVA).We determined 43 Brucella suis genotypes. Strains were grouped according to phylogenetic and geographic relationships, revealing both regional specificity and uniqueness and suggesting possible sources and modes of spread among animals. Our study also confirmed problems with Bruce19 locus that may hinder comparisons of new types with those in the international database.Forty-one novel genotypes were identified and deposited into the international database. Our study supports the idea of wild animals as a source of disease in domestic animals and also gives evidence to hypothesis of cross-border animal trafficking between former Yugoslavian countries. It also highlights the need to expand such research across more of southeast Europe, especially to countries with poorer social and economical situation in order to prevent a realistic outbreak and for better understanding of the biology of this pathogen.

A Serosurvey for Brucellosis in Wild Boar (Sus scrofa) in Sardinia, Italy.

Porcine brucellosis is a zoonotic disease caused by Brucella suis and hosted by pigs (Sus scrofa). Both domestic pigs and wild boars are affected. We measured the prevalence of antibody to Brucella spp. in wild boars in Sardinia, Italy. During 1 November 2009 to 31 January 2010, we collected 570 serum samples from legally hunted wild boars and tested them using a commercial competitive enzyme-linked immunosorbent assay. Sex and age class of the sampled wild boars were also recorded. Thirty-five samples were positive for an apparent antibody prevalence of 6.1%. Antibody prevalences did not differ between sexes or among age classes.

Genetic relatedness of Brucella suis biovar 2 isolates from hares, wild boars and domestic pigs

Porcine brucellosis generally manifests as disorders in reproductive organs potentially leading to serious losses in the swine industry. Brucella suis biovar 2 is endemic in European wild boar (Sus scrofa) and hare (Lepus europeus, Lepus capensis) populations, thus these species may play a significant role in disease spread and serve as potential sources of infection for domestic pigs. The aim of this study was an epidemiologic analysis of porcine brucellosis in Hungary and a comparative analysis of B. suis bv. 2 strains from Europe using multiple-locus variable-number tandem repeat analysis (MLVA). MLVA-16 and its MLVA-11 subset were used to determine the genotypes of 68 B. suis bv. 2 isolates from Hungary and results were then compared to European MLVA genotypes. The analyses indicated relatively high genetic diversity of B. suis bv. 2 in Hungary. Strains isolated from hares and wild boars from Hungary showed substantial genetic divergence, suggesting separate lineages in each host and no instances of cross species infections. The closest relatives of strains from Hungarian wild boars and domestic pigs were mainly in the isolates from German and Croatian boars and pigs. The assessment of the European MLVA genotypes of wild boar isolates generally showed clustering based on geographic origin. The hare strains were relatively closely related to one another and did not cluster based on geographic origin. The limited relationships between geographic origin and genotype in isolates from hares might be the result of cross-border live animal translocation. The results could also suggest that certain B. suis strains are more adapted to hares. Across Europe, isolates from domestic pigs were closely related to isolates originating from both hares and wild boars, supporting the idea that wild animals are a source of brucellosis in domestic pigs.

The porcine brucellosis – evidence of the role of Yersinia enterocolitica O:9 in occurrence of false positive serological reactions

Forty four pigs with typical characteristics for false positive serolpgical reactions (FPSR) were examined for the presence of Yersinia enterocolitica O:9. The positive reactions were observed in rose bengal test (RBT, N = 23 sera), serum agglutination test (SAT, N = 16), complement fixation test (CFT, N = 9), indirect ELISA (i-ELISA, N= 11) in first, and in RBT (N = 14), SAT (N = 8), CFT (N = 7) and i-ELISA (N = 18) in second examination, respectively. In bacteriological examination Y enterocolitica was confirmed in 12 cases. Six of these isolates were identified with PCR as Y enterocolitica 0:9.

High-Density Dependence But Low Impact on Selected Reproduction Parameters ofBrucella suisBiovar 2 in Wild Boar Hunting Estates from South-Western Spain

Porcine brucellosis is a disease caused by Brucella suis, which is characterized by reproductive disorders in pigs. The number of cases of swine brucellosis has risen in many European countries, likely because of the presence of a wild reservoir of B.suis in wild boar. This study aimed at evaluating factors that may influence the probability of infection with Brucella spp. in wild boar and at assessing the impact of a previous contact with Brucella spp. on reproductive parameters of wild boar. Two hundred and four wild boar living in Extremadura (south-western Spain) were studied. The presence of anti-Brucella antibodies was determined using an indirect ELISA, while the presence of living bacteria in genital organs was evaluated through microbiological cultures. Sex, age, density of wild boar in summer and presence of outdoor pigs were selected as possible risk factors for being seropositive for Brucella spp. in wild boar. In addition, reproductive parameters such as breeding status or potential fertility in females and testis weight in males were estimated and related to the presence of anti-Brucella antibodies. A total of 121 animals were seropositive, resulting in a prevalence of 59.3% (95% CI). In addition, seven isolates of B.suis biovar 2 were obtained. Wild boar density in summer, as well as age and sex, was proposed as factors to explain the probability of Brucella seroconversion, although wild boar density in summer was the key factor. Current measures of reproductive parameters were not influenced by a previous contact with Brucella spp. Isolation of B.suis confirms that wild boar could represent a risk to domestic pig health in the study area. Wild boar density seems to have a great influence in the probability of infections with B.suis and suggests that density management could be useful to control Brucella infection in wild boar.

Zoonosis Due to &amp;lt;i&amp;gt;Bruella suis&amp;lt;/i&amp;gt; with Special Reference to Infection in Dogs (Carnivores): A Brief Review

Brucella suis (B. suis) is the major cause of porcine brucellosis. Zoonosis due to B. suis infection associated with transmission by various animal species is reported. Recently an increase in brucellosis associated with feral swine transmitted B. suis infection in humans and hunting dogs is emerging. Reports on B. suis infection in carnivores including dogs is scant. This report gives a brief review of B. suis zoonosis with particular reference to B. suis infection in dogs (carnivores).

Value of Fluorescence Polarisation Assay in Comparison to Traditional Techniques in Diagnosis of Porcine Brucellosis

Abstract The aim of this study was the evaluation of fluorescence polarisation assay (FPA) in the diagnosis of porcine brucellosis in comparison with Rose Bengal test (RBT), serum agglutination test (SAT), complement fixation test (CFT), 2-mercaptoethanol test, and ELISA. Eight hundred seventeen sera from pigs, including 612 sera from healthy animals, seven sera from Brucella suis bv2 culture positive animals, and 198 sera classified as false positive, originated from confirmatory investigations, were used. All sera from healthy animals, negative in RBT, SAT, CFT, and ELISA were also negative in FPA. All sera positive in serological examination, originated from Brucella infected animals, were also positive in FPA. Among sera classified as false positive almost half of the samples tested (49.49%) reacted positively in FPA. The examinations confirmed the usefulness of FPA in diagnosis of porcine brucellosis, but the method, like the other tests, does not allow resolving the problem of discrimination cross-reacting from specific antibodies.

Evaluation of five serological tests for the diagnosis of porcine brucellosis in French Polynesia

Porcine brucellosis due to Brucella suis biovar 1 raises important issues for pig breeders in French Polynesia. In this region, the disease is enzootic, spreads silently and engenders economic losses in infected farms as well as sporadic human cases. While serological tests are essential in surveillance and control programmes of animal diseases, to date none of the available tests have been shown to be reliable enough to be used as a gold standard in routine individual diagnosis of porcine brucellosis. Few studies about the estimation of the sensitivity and the specificity of porcine brucellosis screening tests have been published, none of them dealing with French Polynesia. The studied population included 1,595 pigs from French Polynesia. Five tests were evaluated: Rose Bengal test, fluorescence polarisation assay, indirect ELISA, and two competitive ELISAs (C-ELISA). The sensitivity and the specificity of each test were estimated. C-ELISA2 was the most sensitive test (Se C-ELISA2=0.954 [0.889; 0.992] 95% credibility interval (CrI)) while both C-ELISA and Rose Bengal test (RBT) were the most specific ones (Sp C-ELISA1=0.856 [0.806; 0.915] 95% CrI; Sp C-ELISA2=0.849 [0.817; 0.879] 95% CrI; Sp RBT=0.853 [0.812; 0.898] 95% CrI).

An evaluation of the capability of existing and novel serodiagnostic methods for porcine brucellosis to reduce false positive serological reactions

Porcine brucellosis is a zoonotic disease of truly global significance because even in countries without the disease the occurrence of false positive serological reactions (FPSRs) creates significant problems. Statutory diagnostic testing is required in many disease free countries or regions and is often a prerequisite for the movement of live animals. Currently this testing is dependent almost entirely on serological assays and these may result in a significant number of FPSRs. The aim of this study was to examine existing and novel serodiagnostic assays to evaluate their diagnostic sensitivity and resilience to FPSRs. The existing assays evaluated were the RBT, smooth lipopolysaccharide (sLPS) indirect (i) ELISA, sLPS competitive (c) ELISA, and the FPA. The novel assays evaluated were the sLPS TR-FRET assay, a rough (r) LPS iELISA, a recombinant protein BP26 iELISA and a cytoplasmic protein extract (Brucellergene™) iELISA. Four populations of sera were evaluated: those from Brucella suis infected swine (n=34), randomly selected samples from non-infected swine (n=161), sera from non-infected swine within herds exhibiting FPSRs (n=132) and sera from swine experimentally infected with Yersinia enterocolitica O:9 (n=4). The results show that all the assays dependent on the sLPS O-polysaccharide (OPS) for their sensitivity (the RBT, sLPS ELISAs, FPA and the sLPS TR-FRET) had significantly reduced diagnostic specificity when applied to the FPSR population, the RBT being most affected. Of the two rapid homogeneous assays, the TR-FRET was diagnostically superior to the FPA in this study. Neither of the protein based iELISAs demonstrated sufficient diagnostic sensitivity to resolve the FPSRs. The rLPS iELISA showed no cross reaction with the FPSRs and had diagnostic sensitivity similar to that of the OPS based assays.