Rapid Agglutination Test Research Articles

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.

Quantification of the effect of vaccination on the control of horizontal transmission of Mycoplasma synoviae under field conditions

ABSTRACT Beside biosecurity, vaccination is important for Mycoplasma synoviae (MS) control as it has been shown to contribute to the reduction of economic impact and, experimentally, also lessens horizontal transmission. In this study, the effect of MS live vaccination on horizontal transmission was quantified under field conditions by analysing 4-year MS monitoring data from non-MS-vaccinated broiler and layer breeders and MS-vaccinated broiler breeders with good biosecurity in single-age housing systems. Flocks were monitored at 20 and 30 weeks of age and every 12 weeks thereafter. At every sampling, 60 blood samples or 24 tracheal swabs were tested using rapid plate agglutination test and ELISA serially or MS DIVA PCR, respectively. The MS incidence rate was calculated and the association with vaccination was analysed by logistic regression. The average MS incidence rate per 1000 weeks was 11.6 cases for non-MS-vaccinated broiler breeders and decreased from 29.6 to 5.6 cases with successive vaccinated production cycles. In non-MS-vaccinated layer breeders it was 3.6. A significant negative association with MS incidence was found after vaccinating four to six successive production cycles compared to non-MS-vaccinated or only one production cycle vaccinated breeders (odds ratio (OR) = 0.23, P = 0.05 & OR = 0.12, P = 0.01, respectively). A significant negative association with MS in non-MS-vaccinated layer breeders (OR = 0.29, P = 0.00) was observed compared to non-MS-vaccinated broiler breeders, possibly due to more controlled contact structures within the layer breeder industry. The results suggest that vaccination and control of contacts contribute to the reduction of between-farm MS transmission.

A Salmonella Pullorum outbreak with neurological signs in adult layers and outbreak investigation using whole genome sequencing

ABSTRACT This report describes a Salmonella enterica subspecies enterica Serovar Gallinarum Biovar Pullorum (SP) outbreak in a Dutch laying flock of 65 weeks of age (W) showing increased mortality, decreased egg production, and neurological signs. The flock was vaccinated three times with a live S. enteritis and S. typhimurium vaccine in the rearing period. At 71 W, as mortality peaked, a live SG 9R vaccine was applied. At 76 W, mortality decreased and egg production stabilized but did not return to a normal level. Post-mortem, histological, bacteriological, and serological examinations were frequently performed. Gross findings in diseased and dead birds were characterized by hepatomegaly, splenomegaly, and oophoritis. SP was frequently isolated from the liver, spleen, ovary, and bone marrow, and the isolation rate did not vary significantly between the different organs. In birds with neurological signs, histological examination and immunostaining showed cerebral granulomas in the presence of Salmonella. Previous Salmonella vaccinations did not hamper the detection of specific SP antibodies (positive at serum dilution ≥ 1:8) using a commercial rapid plate agglutination test. At 85 W, 40 clinically healthy birds were investigated and three had ovarian lesions, explaining egg production not returning to normal. These birds had antibodies against SP, indicating contact with the bacterium, but carrier status could not be confirmed by culture. Phylogenetic analysis showed SP isolates within this outbreak to be clonal and differing from SP isolates from previous outbreaks. RESEARCH HIGHLIGHTS Cerebral granulomas are associated with nervous signs in Salmonella Pullorum outbreak. Bone marrow is also a recommended tissue for isolation of Salmonella Pullorum. Rapid plate agglutination test detects Pullorum antibodies in a vaccinated flock. Phylogenetic analysis showed clonality of isolates within the outbreak.

Prevalence of major infectious diseases in backyard chickens from rural markets in Morocco.

Raising backyard chickens is a common practice in Morocco, mainly in rural or periurban areas. Constraints due to devastating avian diseases have been recognized as a major limiting factor in backyard poultry production. Consequently, these flocks could potentially be implicated as reservoirs for poultry diseases. However, there is a considerable lack of information on disease prevalence in this production system, and the risk represented by these small flocks remains under debate. This study aimed to estimate the seroprevalence and identify related risk factors of a range of bacterial and viral pathogens of outstanding importance for the economy and public health in backyard poultry in Morocco. A total of 712 sera samples and 258 cloacal swabs were collected from 712 backyard chickens from 15 rural markets in the Khemisset and Skhirat-Temara provinces. None of the sampled chickens received any vaccination. Sera samples were screened for antibodies against Newcastle disease virus (NDV) and low pathogenic avian influenza H9N2 subtype (LPAI H9N2) using a hemagglutination-inhibition test, against bursal infectious disease virus (IBDV) and infectious bronchitis virus (IBV) using enzyme-linked immunosorbent assay, and against Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) using a rapid serum agglutination test. Swab samples were compiled into 86 pools and submitted for molecular detection using real-time reverse-transcription-polymerase chain reaction (RT-PCR). The seroprevalences in backyard chickens for NDV, LPAI H9N2, IBDV, IBV, MG, and MS were 52.1% (371/712), 63.5% (452/712), 84.7% (603/712), 82.2% (585/712), 58% (413/712), and 74.8% (533/712), respectively. Based on the RT-PCR results, 2.3% (2/86), 62.8% (54/86), 2.3% (2/86), 63.9% (55/86), 40.7% (35/86), and 29.1% (25/86) of the pools were positive for NDV, H9N2 LPAI, IBDV, IBV, MG, and MS, respectively. Multiple coinfections (H9N2-IBV-MG), (H9N2-IBV-MS), or (IBV-MG-MS) were observed in 15.1%, 8.5%, and 8.5% of the tested samples, respectively. The results show that backyard chicken flocks and rural markets have the potential to serve as reservoirs or amplifiers for poultry pathogens and could pose a risk to the commercial poultry sector. This highlights the need for a comprehensive and adapted vaccination plan for backyard chickens, and extension of efforts to increase flock owners' awareness of avian diseases and incite the implementation of biosecurity measures at the farm level.

TECHNIQUES OF PURIFICATION of ANTIGEN O ISOLATES of Escherichia coli AND IN VIVO ANALYSIS OF ANTIGEN IMMUNOGENICITY IN POULTRY

Lipopolysaccharide (LPS) is a major surface component of most Gram-negative bacteria and is recognized by immune cells as pathogen-associated molecules. Antibodies against O antigens can provide protection against infection and vaccines have been developed by conjugating O antigens to carrier proteins to enhance immunogenicity. This study aims to produce O antigen from Escherichia coli and analyze the in vivo test results in poultry using ELISA technique. The methods used in this study were E. coli Bacterial Culture, O Antigen Purification, SDS PAGE, Inoculation on Experimental Animals, Rapid Plate Agglutination Test, and ELISA. Based on the results of the research conducted, it can be concluded that the O antigen of Escherichia coli injected into chickens can induce the formation of specific antibodies against E. coli in the blood. Specific antibodies to E. coli formed can be detected using the rapid plate agglutination test and ELISA technique.

Seroprevalence of Salmonella spp. infection in different types of poultry and biosecurity measures associated with Salmonellosis

Salmonella spp. infection is considered a crucial trouble of the poultry industry in Bangladesh. Hence, this study was aimed to estimate the seroprevalence of Salmonella spp. in poultry along with biosecurity practices that are associated with this Salmonella spp. infection. The study was conducted during the period from January to September, 2021 in Mymensingh and Gazipur district of Bangladesh. A total of 314 samples were considered to determine the seroprevalence. Seroprevalence was determined by performing the rapid serum plate agglutination test. The result revealed that the overall Salmonella spp. seroprevalence was 47.77% in the study area. The higher seroprevalence was in Mymensingh (51.59%) than Gazipur (45.21%) without significant (p>0.05) difference. The highest seroprevalence was in broiler (51.33%) where in layer and sonali was 32.67% and 16% respectively. Seroprevalence was significantly (p<0.05) higher in summer for layer (56.45%), broiler (60.64%) and sonali (51.22%) than the winter seasons. In layer farms, the flock size of >2000 to <2500 had significantly (p<0.05) higher (71.43%) seroprevalence. In broiler farms, 15 to 30 days old birds had significantly (p<0.01) higher (77.05%) seroprevalence than other age. Among the different categorical level of biosecurity practices, the poultry farms that used surface water (OR=0.182, 95% CI=0.106-0.314); disinfectant regularly (OR=0.296, 95% CI=0.171-0.511); having density of 8-10 birds/meter2 (OR=0.379, 95% CI=0.219-0.654); cleaned waterer and feeder regularly (OR=0.503, 95% CI=0.294-0.862); and having visitor restriction (OR=0.375, 95% CI=0.219-0.643) showed lower tendency (p<0.001) to seroprevalence. In brief, Strict farm hygienic practice and biosecurity measures are significantly linked to decrease the Salmonella spp. seroprevalence.

Salmonella Pullorum in a Free-range Chicken Farm in Western Bahia, Brazil

Background:Industrial poultry farming has developed progressively in Brazil, conferring the country a prominent position on the national and international scene. Likewise, alternative poultry farming is an important economic activity for small-scale family farmers. However, shortcomings related to sanitary management lead to increased occurrence of avian diseases, such as those caused by Salmonella spp. Despite salmonellosis has been described in industrial establishments, reports in alternative farms are less common, therefore the objective of this study was to describe the occurrence of salmonellosis in free-range chickens in the municipality of Barra, Western Bahia, Brazil. Cases: The poultry farmer reported the occurrence of diarrhoea in his chicken flock since the acquisition of the batch of chicks. Initially, carrying out the medicinal treatment of the birds, there was clinical improvement, however, successive recurrences of clinical signs occurred, such as diarrhoea, apathy, anorexia, and death of some birds. Upon learning about the case, an epidemiological investigation of the flock was carried out, and it was noted that some of the birds were retracted, apathetic, anorexic, and a lot of diarrheic faeces of a yellowish-white appearance were also observed. The entire flock had a history of vaccination against diseases: newcastle disease, infectious bronchitis, gumboro disease, and fowlpox. For better evaluation, five birds were necropsied, enabling the observation that the animals had a good body score. However, the necropsy revealed lesions such as splenomegaly, hepatomegaly, and enteritis in the three birds initially analysed (Animals 1, 2, and 3). The other birds (Animals 4 and 5) were submitted to evaluation for Eimeria sp. oocysts by means of scrapings from the intestinal mucosa, and there were no structures compatible with oocysts. Faecal samples were collected from another six birds in the flock for coproparasitological examination, and the presence of oocysts was not detected. Finally, sera from 20 birds in the flock were collected for the Rapid Serum Agglutination Test (SAR) for the detection anti-Salmonella Pullorum antibodies. Discussion: The diagnosis was based on clinical evaluation, post-mortem pathological findings of the necropsied birds, epidemiological data and confirmed with SAR testing, whereby 11 birds were seropositive for Salmonella enterica subspecies enterica serovar Pullorum. The prevalence of S. Pullorum is poorly described in alternative farming. Based on the farmer's report, it is believed that the chicks were purchased already infected, because birds from the same batch, also purchased by neighbouring producers, showed the same clinical signs. The unsatisfactory sanitation in the flock was another factor that may have favoured the persistence of the bacteria, since, the lack of removal of organic matter is a source of nutrients for microorganisms, and this may have favoured the multiplication and maintenance of the bacteria in the down feathers, feed, and water. The elimination of S. Pullorum through the faeces, in addition to the density of the birds, may have led to transmission to the other healthy birds. However, the knowledge and adoption of prophylactic measures in free-range chicken farms is a crucial factor in minimizing the occurrence of outbreaks and thus avoiding a future public Health Problem. Keywords: poultry pathology, alternative poultry farming, salmonellosis. Título: Samonella Pullorum em criação de galinhas caipiras no Oeste da Bahia, Brasil Descritores: patologia aviária, avicultura alternativa, salmoneloses.

Sero Survey of Salmonellosis in Broiler at Sylhet City of Bangladesh

The present study was undertaken to know the seroprevalence of Salmonella infection in broiler chickens in the Sylhet area, Northeastern Bangladesh. This investigation was conducted from 10 December 2018 through 20 January 2019. A total of 250 sera samples were collected from five live bird market of the Sylhet metropolitan area and subjected to rapid serum plate agglutination (RSPA) test using commercial salmonella antigen (LilliTest) to detect the presence of antibodies against salmonella infection. The overall prevalence of salmonella infection in the five live bird market visited in this investigation were recorded as 30.6%. The highest prevalence (46%) was reported from the samples of Lama bazar. And the lowest prevalence (20%) was reported from the samples of Mirabazar. It has been found that Salmonella infections are still significant disease problems in broiler farms in the Sylhet region. Keywords: Prevalence, Mirabajar, Antigen, Agglutination, Infection DOI: 10.7176/JNSR/12-20-01 Publication date: October 31 st 2021

​Incidence and Pathology of Paratyphoid Infection in Poultry

Background: Paratyphoid infection of poultry is caused by non-host adapted motile salmonellae and are responsible for numerous cases of food borne illness worldwide. The present study was carried out from July 2019 to February 2020 in Jabalpur to know the occurrence and pathology of paratyphoid bacteria in poultry. Methods: Whole blood agglutination test was performed to know the prevalence of salmonellosis in and areas surrounding Jabalpur region and pooled fecal samples were collected from poultry farms to perform microbe culture and biochemical characterization. Serotyping of Salmonella isolates was done using polyvalent antisera. Necropsy examination was conducted to observe gross and histopathological lesions. Conclusion: Rapid whole blood agglutination test determined the percent prevalence of Salmonella as 28.0% from 25 private poultry outlets. The percent prevalence of salmonellosis by collecting pooled fecal samples from 15 broiler and 11 layer farms was recorded as 20.0% and 45.4% respectively. Salmonellosis was recorded in 1.58% of total necropsy cases of birds examined for gross and histopathological studies. Polyvalent antisera diagnosed 27.27% motile paratyphoid salmonellae, out of which 18.18% tested positive for Salmonella Enteritidis while 9.09% tested positive for Salmonella Typhimurium. Birds with paratyphoid infection showed hepatomegaly, discoloration, hemorrhagic and necrotic foci in liver and various grades of hemorrhagic to catarrhal enteritis were recorded.

Investigation on Seroprevalence of Mycoplasma Gallisepticum Infection in Commercial Layer Farms in Rajshahi District Using Rapid Serum Plate Agglutination Test

Mycoplasma gallisepticum (MG) infection is very common in birds that cause respiratory infections in chickens, turkeys, and other avian species. It has brought about a considerable amount of financial losses to the poultry sector in Bangladesh. We conducted a study on the Seroprevalence of MG infection in two different geographical areas of Bangladesh under Rajshahi district, namely Paba and Bagmaraupazila. 800 sera samples were collected and tested with Rapid Serum Plate Agglutination Test (RSA) to identify the MG antibodies using commercial Mycoplasma gallisepticum antigen. The gross Seroprevalence of MG infection was 59.25% in the study area. The maximum rate (68.80%) of infection was found in the winter season, followed by the summer season (49.36%). The result further revealed that the condition was higher (69.01%) in larger-sized flocks than in small (53.63%). We noticed that younger birds having 10-20 weeks of age are more prone to be affected with avian mycoplamosis with an infection rate of 72% compared to their adult counterpart of 71+ weeks with 52% morbidity. Our study revealed that Mycoplasma gallisepticum infection is prevalent in Paba and Bagmaraupazila in Rajshahi. The farms should take strict bio-security measures to mitigate this infection in the mentioned areas. Proper medications for the affected birds and timely prophylactic measures for the healthy ones could be practical and preventive strategies against avian mycoplasmosis. Amid limitations, we conducted our experiments, and thus further research is warranted to substantially assess and validates our observations.

Brucellosis and its associated risk factors to humans and domestic ruminants in Kagera Ecosystem, Tanzania.

Brucellosis is an important disease for both veterinary and public health. A study was conducted to understand the seroprevalence of brucellosis and its associated risk factors in pastoral areas of Kagera, Tanzania. Sera from 156 patients with malaria-like symptoms were analyzed using the commercial rapid agglutination test (specific for B.abortus and B.melitensis detection) and Fluorescence Polarization Assay (FPA). Sera from 426 cattle, 206 goats and 197 sheep were analyzed using Rose Bengal Plate (RBPT) and Competitive ELISA (c-ELISA) tests. In humans, overall brucellosis, B. abortus, and B. melitensis sero-prevalences were 7.7% (95%CI: 3.8-12.2%), 1.9% (95% CI: 0.4-4.5%), and 5.8 % (95%CI: 2.6-10.6%), respectively. At animal level, seropositivity was 5.9% (95%CI: 4.0-8.6%), 2.5% (95%CI: 0.8-5.7%) and 0.5% (95%CI: 0.01-2.8%) in cattle, goats and sheep, respectively. At herd level, seropositivity was 18.2% (95%CI: 12.0-25.8%) in cattle and 6.9% (95%CI: 2.2-15.3%) in small ruminants. Brucellosis was associated with assisting in parturition without wearing protective gears (OR= 5.6; p= 0.02) in humans, herds of 50-200 animals (OR= 4.2, p= 0.01) and cattle (OR=3.5; p=0.01). The knowledge of brucellosis among pastoralists (OR=0.1; p<0.01) was a protective factor. Brucella infections could be occurring in pastoralists and domestic ruminants in Kagera. Community health education is necessary for the control of brucellosis in Tanzania.

Evaluation of buffered Trypanosoma evansi antigen and rapid serum agglutination test (BA/Te) for the detection of anti-T. evansi antibodies in horses in Brazil

Surra is an infectious disease caused by Trypanosoma evansi, which affects a large number of domestic and wild animal species. Infection control is based on rapid diagnosis followed by treatment of sick animals. This study aimed to evaluate a buffered T. evansi antigen and rapid serum agglutination test (BA/Te) for the detection of anti-T. evansi antibodies in serum samples of horses. For this purpose, 445 serum samples from horses were evaluated and the results compared with the diagnosis by CATT/T. evansi. Our data show a sensitivity of 92%, specificity of 91% and a degree of agreement kappa (κ) of 0.82 (95% CI: 0.771–0.877, P < 0.01) between BA/Te and CATT/T. evansi. Antigen specificity was also evaluated against reactive serum for other infectious agents circulating in equine herds. In conclusion, our findings show that BA/Te has the potential to be a practical and quick screening method for the detection of anti-T. evansi antibodies in horses.

Brucella melitensis B115-based ELISA to unravel false positive serologic reactions in bovine brucellosis: a field study

BackgroundBrucellosis is a zoonosis whose incidence is not declining worldwide despite the global effort to control the disease. Accurate and precise diagnosis is a crucial step in any prophylaxis program but single tests to unequivocally detect animals infected with Brucella spp. are currently unavailable. In Italy, serological diagnosis of bovine brucellosis is performed with two official tests: a rapid agglutination test (i.e., Rose Bengal Plate test, RBPT) and a complement fixation test (CFT) that detect antibodies directed mainly to the smooth lipopolysaccharide (S-LPS). Neither of the two tests is able to avoid the detection of false positive serological reactions (FPSRs) caused by bacteria sharing S-LPS components with Brucella spp. and responsible for the single reactors (SR) phenomenon. A B. melitensis R strain-based ELISA showed a good diagnostic performance in unravelling FP animals; however, since a limited number of animals were analyzed in that study, a large field study was conducted here to discriminate between Brucella-infected from FP animals, with the final aim of reducing the unnecessary slaughter of the latter. An ELISA based on a R strain of Brucella, i.e., Brucella melitensis B115, was employed to measure specific IgG responses in a collection of bovine sera (n = 648). Sera were obtained from 180 farms (either officially brucellosis-free or not brucellosis-free) recruited during an extended period of time (2014–2018) and were preliminarily assayed with the official tests by the Italian Reference Centers and then subjected to the ELISA.ResultsNegative sera, when subjected to the ELISA, gave O.D. values below the cutoff; SR sera, i.e. RBPT positive and CFT negative, as well as double positive (DP) sera, i.e. RBPT and CFT positive, gave O.D. values that were below the cutoff. All positive sera, i.e. from Brucella-infected animals, were RBPT positive and CFT positive (ICFTU ranging from 20 to 1280) and gave ELISA O.D. values above the cutoff.ConclusionsThe B. melitensis B115-based ELISA systematically unravelled all false positive (FP) sera while confirming the diagnosis in Brucella-infected animals. Thus, the test employed in the present study may complement the official assays to avoid the costly slaughter of FP animals.

Rate of false positive reactions in 11 M. gallisepticum and M. synoviae serological tests in samples obtained from SPF birds inoculated with heterologous mycoplasma species

ABSTRACT No recent information is available on the specificity of current M. synoviae (Ms) and M. gallisepticum (Mg) serological tests. In this study the performance of a currently available Mg and Ms Rapid Plate Agglutination (RPA) test, and three Mg, three Ms and three Mg/Ms combination ELISAs were evaluated on SPF sera that were obtained from days (D) 0–28 after M. gallinarum, M. imitans or M. gallinaceum inoculation, after sham inoculation and without inoculation. Tracheal swabs for mycoplasma culture were obtained before inoculation (D0), 7 and 28 days post inoculation (d.p.i.) in all groups except the sham inoculated group. The different mycoplasma species colonized well. In the early stage after inoculation (7–14 d.p.i.) with heterologous mycoplasma species, the specificity varied from 85% to 100% in the Mg RPA test and from 70% to 85% in the Ms RPA test. The specificity of both Mg and Ms RPA test was 100% in the sham inoculated samples and ruled out the effect of sham medium. In the late stage (21-28 d.p.i.) specificity was 100% for both RPA tests. The test specificity was 100% for seven ELISAs except for two combination ELISAs where a specificity of 95% was found in the late stage after inoculation. However, this was not significantly different from the specificity of all other tests in the late stage of these groups. These results show that it is not advisable to establish Mg and Ms seromonitoring programmes on the Mg and Ms RPA test alone as other mycoplasma species frequently occur in poultry.

Seroprevalence of brucella antibodies in horses in Sokoto metropolis, Nigeria

The study was conducted to determine the prevalence of Brucella antibodies in horses reared in Sokoto metropolis using the rapid-plate test, serum agglutination test and Competitive ELISA. A total of 347 horses were sampled comprising of 329 males and 9 females within the age range of 1 to above ten years. The serum samples were harvested and subjected to Rapid Plate Test, CompELISA and Serum Agglutination Test. Out of the 347 horses sampled, 48 were found to be positive for the Rapid Plate Test and CompELISA while 41 were positive for Serum Agglutination Test. Thus, an overall prevalence of 13.83% was realized. Also, 7 horses had antibody titre of 1:40, 12 had 1:60 titre, while 29 had 1:80. The prevalence of Brucella antibodies was highest in males (14.28%) compared to females (0%). The seroprevalence to brucella antibodies was found not to be statistically significantly associated with sex of the horses as observed in this study. Horses between the age of 6 to 10 years had a higher prevalence of Brucella antibodies 24 (16.32%) as compared to those 0 to 5 years 21 (12.5%) and those above ten years 3 (9.37%). Age was also not a significant factor for brucella antibody seropositivity (p = 0.588). This study indicates that Brucellosis is prevalent in horses in Sokoto. Hence, horse attendants and livestock reared together are at risk of contracting brucella infection.

Relative contribution of vertical, within-farm and between-farm transmission of Mycoplasma synoviae in layer pullet flocks

ABSTRACT In this study, the relative contribution of vertical transmission, within-farm transmission and between-farm transmission of Mycoplasma synoviae in layer pullet flocks was quantified using logistic regression analysis. Data from 311 Dutch pullet flocks, of which 172 (55%) were positive for M. synoviae, were included in the study. Also the M. synoviae status of the parent stock of these flocks was included. The M. synoviae status was determined with the M. synoviae rapid plate agglutination test. Data analysis showed that vertical transmission was the most important transmission route for M. synoviae in layers as is demonstrated by an odds ratio of 5.8 (P = 0.000). A positive association with M. synoviae infections was found for layer pullet flocks on a multi-house farm where at least one other flock was M. synoviae-positive compared to single-house farms (odds ratio 3.1, P = 0.022), while a negative association was found when no other M. synoviae-positive flocks were present (odds ratio = 0.2, P = 0.003). No association was found between M. synoviae status of pullet flocks and poultry farm density. Odds ratios were 0.54 (P = 0.288) and 0.34 (P = 0.073), respectively, for medium and highest poultry farm density compared to lowest poultry farm density. This is the first time that the relative contribution of horizontal and vertical transmission of M. synoviae has been quantified. These results can be extrapolated to M. synoviae control in general, and emphasize the importance of M. synoviae control in parent stock and practical channelling.

Seroprevalence of Salmonella Infection in Commercial Layer Chickens in Cox’s Bazar District, Bangladesh

Salmonellosis is a zoonotic disease, usually transmitted from animal to human and vice versa and causes huge economic losses in poultry industry of Bangladesh. This study was aimed to estimate the seroprevalence of Salmonella infection in commercial layer farms of Cox’s Bazar district of Bangladesh, during the period from February to April, 2016. A total of 200 blood samples were collected from 20 farms of 4 randomly selected upazillas of Cox’s Bazar considering the age groups, and flock sizes. Rapid serum plate agglutination test was done and 42% chickens were found positive for Salmonella infection. With respect to age groups, the seroprevalence was higher (68%) in adults compared to young (20%) chickens. However, the seroprevalence of Salmonella infection was recorded remarkably (54.28%) in large flocks compared to small flocks. In conclusion, we can say that, Salmonella infection is prevalent in the commercial layer chickens of Cox’s Bazar district, Bangladesh. Appropriate measures and strategies should be taken for successful prevention and control of this disease in Bangladesh.

Detecção de anticorpo anti-Brucella sp. e anti-Leptospira spp. em búfalos (Bubalus bubalis) abatidos em matadouro na cidade de Belém, Pará

The present study aimed to detect the presence of buffalos serum reagents for Brucella sp. and Leptospira spp. Serum samples from 113 animals from Marajo Island, slaughtered at a slaughterhouse in the city of Belem, Para, were used, which were submitted to the Rapid Agglutination Test with buffered, acidified plate antigen (BAPA) and 2-Mercaptoethanol ( 2-ME) for the detection of antibodies against Brucella sp. and the Microscopic Agglutination Test (MAT) for the detection of agglutinins against Leptospira spp. From the 113 samples analyzed, 13.3% (15/113) were reagents for Brucella sp. antibodies in AAT and 6.1% (7/113) were confirmed in the 2-ME test. For Leptospira spp., 35.4% (40/113) of the buffalos were reactive with serovar Hardjo C.T.G., present in 75% (30/40) of the reactions. It was concluded that antibodies against the investigated agents were detected, demonstrating the need to make a more efficient sanitary control in the herd.

Rapid serum agglutination, cultural isolation and PCR for detection of M. gallisepticum and M. synoviae infection in poultry

Poultry mycoplasmosis, is an infectious disease of birds distributed worldwide causing serious economic loss to the poultry industry. Diagnosis of poultry mycoplasmosis is considered to difficult task due to different aspects of etiological agent from conventional bacteria. Therefore, the present study was aimed to detect mycoplasma infection in poultry using serological, cultural and molecular techniques. The specimens included were, sera samples and choanal swabs (150 each) collected from 150 birds housed in semi arid and costal area of Maharashtra (India). Mycoplasma gallisepticum (MG) was more prevalent than Mycoplasma synoviae (MS) in mycoplasmosis detected by rapid serum agglutination test (RSA), cultural isolation and direct PCR of samples. Nucleotide sequences of three representative MG isolates with NCBI accession nos. KY467400, KY467401 and KY467403 did not show any variations in their sequences analysed and matched with published strains of MG. RSA, cultural isolation and direct PCR yielded 93 (62%), 24 (16%) and 85 (56.67%) positive cases respectively. The sensitivity of PCR and RSA was 95.83% and 83.33% respectively. Thus, RSA and PCR were better than cultural isolation in diagnosis of poultry mycoplasmosis, therefore these methods can be used for screening the flocks for detection of mycoplasma infection depending on availability of specimens and facility.

Seroprevalence of brucellosis in different kinds of feline population in north-east of Iran

The objective of this survey was to assess the prevalence of brucellosis with focus on Brucella abortus and Brucella melletensis in different kinds of cats in north-east of Iran. Different kinds of cats included stray, pet, and cats which were located in dairy cattle herds tested. Blood sera of 48 (34.28%) stray, 42 (30%) pet, and 50 (35.71%) cats collected from 15 industrial dairy cattle herds. They were used for rapid and tube agglutination tests such as Rose Bengal, Wright, and 2-mercaptoethanol (2-ME). The comparison among age, sex, weight, and lifestyle of cats with serological tests of brucellosis were examined statistically. Totally, eight (5.71%) cats were mild positive with low titer. Only two (1.42%) cats reacted in 2-ME. There was no statistically significant relationship between sex of cat (male vs female) and serological results (P = 0.07). However, comparison among different age groups revealed significant differences (p = 0.009). There were no significant differences between the infected cats collected from dairy cattle herds and stray cats, but the stray cats and pet cats showed the significant differences (p = 0.028). This survey showed that Brucella infection (1) mainly occurred in male and stray cats aged 1–2 years and (2) is transiently mild, and (3) negative brucellosis in pet cats represents optimal hygiene and health monitoring of these cats by the owners. So, stray cats can be a risk factor for brucellosis in human and animal populations in north-east of Iran; thus, strong precautions over stray cats are necessary.