Seroprevalence of toxoplasmosis in sheep in South Africa

Serum samples from 600 sheep were collected from 5 different provinces randomly chosen in South Africa. Two sheep abattoirs (representing formal slaughter of sheep) and 1 rural location (representing informal slaughter of sheep) per province were also selected randomly. The serum samples were tested for anti-Toxoplasma gondii IgG antibodies using 2 different serological tests : an indirect fluorescent antibody (IFA) test and an enzyme-linked immunosorbent assay (ELISA) test available as a commercial kit. This study provides the first published data on seroprevalence of toxoplasmosis in sheep in South Africa, although positive titres have been found previously in wild felids, ferrets, chinchillas and a dog. Data on seroprevalence in sheep is considered important because consumption of mutton is universally considered to be a source of zoonotic transfer to humans. Seroprevalence in humans in South Africa was previously found to be 20% and it is postulated that this may be linked to the informal slaughter and consumption of mutton. During this study, the overall national seroprevalence per province in sheep was found to be 5.6 % (IFA) and 4.3 % (ELISA), respectively. This is lower than in other countries, possibly because South Africa has an arid climate. Differences in seroprevalence in different areas studied suggested an association with the climate and a significant correlation (P > 0.05) was detected between the prevalence of T. gondii and the minimum average temperature. The seroprevalence was found to be significantly higher (P < 0.01) in sheep originating from commercial farms (7.9 %) than in rural sheep in the informal sector (3.4 %). Also, sheep managed extensively had a seroprevalence of 1.8 %, which was significantly lower (P < 0.05) than the seroprevalence in sheep under semi-intensive or intensive management systems (5.3 %). An incidental finding of interest was the considerable movement of sheep to abattoirs and mutton after slaughter. The highest consumption of mutton was in the Western Cape Province (29.9 %) while the highest concentration of sheep is found in the Eastern Cape Province (30.1 %).

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Dengue pre-vaccination screening test evaluation for the use of dengue vaccine in an endemic area

PLoS ONE ◽

10.1371/journal.pone.0257182 ◽

2021 ◽

Vol 16 (9) ◽

pp. e0257182

Author(s):

Umaporn Limothai ◽

Sasipha Tachaboon ◽

Janejira Dinhuzen ◽

Taweewun Hunsawong ◽

Prapapun Ong-ajchaowlerd ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Geometric Mean ◽

Dengue Infection ◽

Reference Method ◽

Elisa Test ◽

Enzyme Linked Immunosorbent Assay ◽

Dengue Vaccine ◽

Serum Samples ◽

Serological Tests ◽

Low Sensitivity

Background The dengue vaccine (Dengvaxia) is only recommended for individuals with prior dengue infection (PDI). This study aimed to perform a serosurvey to inform decision-making for vaccine introduction and identify appropriate target populations. We also evaluated the performance of the serological tests using plaque reduction neutralization test (PRNT) as a reference test in identifying PDI to determine suitability for pre-vaccination screening. Methods We enrolled 115 healthy individuals between 10 and 22 years of age living in the Ratchaburi province of Thailand. The serum samples were tested by PRNT to measure the prevalence and concentration of serotype-specific neutralizing antibodies. The performance of the IgG rapid diagnostic test (RDT, SD Bioline, Korea) and IgG enzyme-linked immunosorbent assay (ELISA, EUROIMMUN, Germany) in identifying PDI were evaluated by using PRNT as a reference method. Results Ninety-four (81.7%) individuals neutralized one or more dengue serotypes at a titer threshold greater than or equal to 10. Multitypic profiles were observed in 70.4% of the samples which increased to 91.9% in subjects aged 19–22. Among monotypic samples, the highest proportion was reactive against DENV-1 followed by DENV-2, DENV-3, and DENV-4. The highest anti-dengue antibody titers were recorded against DENV-1 and increased with age to a geometric mean NT50 titer (GMT) of 188.6 in the 19–22 age group. While both RDT and ELISA exhibited 100% specificity, RDT demonstrated low sensitivity (35%) with ELISA displaying much greater sensitivity (87%). Conclusions Almost 80% of adolescents and youth in Ratchaburi province had already been exposed to one or more of the dengue virus serotypes. The dengue IgG RDT displayed low sensitivity and is likely not be suitable for dengue pre-vaccination screening. These results support the use of IgG ELISA test for dengue vaccination in endemic areas.

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Serological Evaluation of Specific-Antibody Levels in Patients Treated for Chronic Chagas' Disease

Clinical and Vaccine Immunology ◽

10.1128/cvi.00106-07 ◽

2007 ◽

Vol 15 (2) ◽

pp. 297-302 ◽

Cited By ~ 38

Author(s):

Olga Sánchez Negrette ◽

Fernando J. Sánchez Valdéz ◽

Carlos D. Lacunza ◽

María Fernanda García Bustos ◽

María Celia Mora ◽

...

Keyword(s):

Chagas Disease ◽

Treatment Effectiveness ◽

Enzyme Linked Immunosorbent Assay ◽

Serum Samples ◽

Serological Tests ◽

Recombinant Antigens ◽

Antibody Titers ◽

Laboratory Procedures ◽

The Individual ◽

Antibody Levels

ABSTRACT Serological tests are the main laboratory procedures used for diagnosis during the indeterminate and chronic stages of Chagas' disease. A serological regression to negativity is the main criterion used to define parasitological cure in treated patients. The aim of this work was to monitor the individual specificities of antibody levels for 3 years posttreatment in 18 adult patients. Conventional serological techniques (hemagglutination assays and enzyme-linked immunosorbent assay [ELISA]) were modified by using recombinant antigens to detect early markers of treatment effectiveness. For this purpose, serum samples were taken before and during treatment and every 6 months after treatment for at least 3 years. When hemagglutination assays were used, a decrease in antibody levels was observed in only one patient. When ELISA with serum dilutions was used, antibody clearance became much more apparent: in 77.7% (14/18) of the patients, antibody titers became negative with time. This was observed at serum dilutions of 1/320 and occurred between the 6th and the 30th months posttreatment. The immune response and the interval for a serological regression to negativity were different for each patient. For some of the recombinant antigens, only 50% (9/18) of the patients reached the serological regression to negativity. Recombinant antigen 13 might be a good marker of treatment effectiveness, since 66.6% (six of nine) of the patients presented with an early regression to negativity for specific antibodies to this antigen (P = 0.002).

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Serological survey of bovine viral diarrhoea virus in Namibian and South African kudu (Tragelaphus strepsiceros) and eland (Taurotragus oryx)

Journal of the South African Veterinary Association ◽

10.4102/jsava.v84i1.937 ◽

2013 ◽

Vol 84 (1) ◽

Cited By ~ 2

Author(s):

Terence P. Scott ◽

Eleanor Stylianides ◽

Wanda Markotter ◽

Louis Nel

Keyword(s):

South Africa ◽

South African ◽

Southern Africa ◽

Bovine Viral Diarrhoea Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Bovine Viral Diarrhoea ◽

Serum Samples ◽

Diarrhoea Virus ◽

Central Regions ◽

Tragelaphus Strepsiceros

Bovine viral diarrhoea virus (BVDV) is a pestivirus that affects members of the order Artiodactyla, including members of the subfamily Bovinae. Little is known about the seroprevalence of BVDV in southern Africa, especially the prevalence in wild ruminant populations such as kudu (Tragelaphus strepsiceros). A handful of random surveys suggested that seroprevalence ranged between 6% and 70% in southern African wild ruminants. The present study aimed to determine the seroprevalence of BVDV amongst kudu and eland (Taurotragus oryx) from Namibia and South Africa. A BVDV-specific enzyme-linked immunosorbent assay was performed on 50 serum samples from kudu and eland from South Africa and Namibia. The seroprevalence of BVDV in South African kudu was 71%, identical to that in Namibian kudu. The seroprevalence in Namibian eland was 40%. The kudu and cattle farming (free ranging) regions in Namibia predominantly overlap in the central regions, ensuring ample opportunity for cross-species transmission of BVDV. It is therefore important to determine the true prevalence of BVDV in southern Africa in both domesticated and wild animals. In addition, a potential link between BVDV incidence and a devastating rabies epidemic in Namibian kudu was proposed and such a notion could be supported or discredited by comparative prevalence data.

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Increased detection of schistosomiasis with Kato-Katz and SWAP-IgG-ELISA in a Northeastern Brazil low-intensity transmission area

Revista da Sociedade Brasileira de Medicina Tropical ◽

10.1590/s0037-86822012000400019 ◽

2012 ◽

Vol 45 (4) ◽

pp. 510-513 ◽

Cited By ~ 17

Author(s):

Teiliane Rodrigues Carneiro ◽

Marta Cristhiany Cunha Pinheiro ◽

Sara Menezes de Oliveira ◽

Ana Lúcia de Paula Hanemann ◽

José Ajax Nogueira Queiroz ◽

...

Keyword(s):

Serological Test ◽

Laboratory Diagnosis ◽

Elisa Test ◽

Northeastern Brazil ◽

Enzyme Linked Immunosorbent Assay ◽

Serological Tests ◽

Predictive Values ◽

Transmission Area ◽

Elisa Technique ◽

Endemic Areas

INTRODUCTION: The laboratory diagnosis of schistosomiasis is based mainly on the detection of parasite eggs in stool samples through the Kato-Katz (KK) technique, reading one slide by test. However, a widely known limitation of parasitological methods is reduced sensitivity, particularly in low endemic areas. METHODS: To increase sensitivity, we conducted further slide readings from the same stool sample using the parasitological method associated with a serological test. We used the KK method (three slides) and the IgG anti-Schistosoma mansoni-enzyme-linked immunosorbent assay (ELISA) technique to diagnose schistosomiasis in low endemic areas in the Brazilian State of Ceará. Fecal samples and sera from 250 individuals were analyzed. RESULTS: Sixteen percent and 47.2% of samples were positive in parasitological tests and serological tests, respectively. Parasitological methods showed that 32 (80%) individuals tested positive on the first slide, 6 (15%) on the second slide, and 2 (5%) on the third. The performance of the ELISA test in the diagnosis, using the KK method as diagnostic reference, showed a negative predictive value of 100%, with specificity and positive predictive values of 62.8% and 33.9%, respectively. CONCLUSIONS: In this study, the increase from one to three slides analyzed per sample using the KK technique was shown to be a useful procedure for increasing the diagnostic sensitivity of this technique.

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The genus Xiphinema in South Africa. XXVI. New information on X. bolandium, with description of the four juvenile stages (Nematoda: Longidoridae)

Koedoe ◽

10.4102/koedoe.v44i2.174 ◽

2001 ◽

Vol 44 (2) ◽

Author(s):

J. Heyns

Keyword(s):

South Africa ◽

Western Cape ◽

Eastern Cape Province ◽

Eastern Cape ◽

Western Cape Province ◽

New Information ◽

Wilderness Area ◽

Juvenile Stages ◽

First Time ◽

New Distribution

A population of Xiphinema bolandium from the Baviaanskloof Wilderness Area in the Eastern Cape Province was studied, and the four juvenile stages described and figured for the first time. New distribution records are listed from several localities in the Western Cape Province, mostly from vineyards and peach orchards, as well as from fynbos.

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Serodiagnosis of Louse-Borne Relapsing Fever with Glycerophosphodiester Phosphodiesterase (GlpQ) fromBorrelia recurrentis

Journal of Clinical Microbiology ◽

10.1128/jcm.38.10.3561-3571.2000 ◽

2000 ◽

Vol 38 (10) ◽

pp. 3561-3571 ◽

Cited By ~ 54

Author(s):

Stephen F. Porcella ◽

Sandra J. Raffel ◽

Merry E. Schrumpf ◽

Martin E. Schriefer ◽

David T. Dennis ◽

...

Keyword(s):

Serological Test ◽

Geometric Mean ◽

Eastern Africa ◽

Enzyme Linked Immunosorbent Assay ◽

Relapsing Fever ◽

Serum Samples ◽

Serological Tests ◽

Whole Cell ◽

Convalescent Phase ◽

Glycerophosphodiester Phosphodiesterase

Human louse-borne relapsing fever occurs in sporadic outbreaks in central and eastern Africa that are characterized by significant morbidity and mortality. Isolates of the causative agent,Borrelia recurrentis, were obtained from the blood of four patients during a recent epidemic of the disease in southern Sudan. TheglpQ gene, encoding glycerophosphodiester phosphodiesterase, from these isolates was sequenced and compared with the glpQ sequences obtained from other relapsing-fever spirochetes. Previously we showed that GlpQ of Borrelia hermsii is an immunogenic protein with utility as a serological test antigen for discriminating tick-borne relapsing fever from Lyme disease. In the present work, we cloned and expressed theglpQ gene from B. recurrentis and used recombinant GlpQ in serological tests. Acute- and convalescent-phase serum samples obtained from 42 patients with louse-borne relapsing fever were tested with an indirect immunofluorescence assay (IFA) and an enzyme-linked immunosorbent assay (ELISA) that used whole cells ofB. recurrentis and with immunoblotting to whole-cell lysates of the spirochete and Escherichia coli producing recombinant GlpQ. The geometric mean titers of the acute- and convalescent-phase serum samples measured by IFA were 1:83 and 1:575, respectively. The immunoblot analysis identified a high level of reactivity and seroconversion to GlpQ, and the assay was more sensitive than the whole-cell IFA and ELISA using purified, recombinant histidine-tagged GlpQ. Serum antibodies to GlpQ and other antigens persisted for 27 years in one patient. We conclude that assessment of anti-GlpQ antibodies will allow serological confirmation of louse-borne relapsing fever and determination of disease prevalence.

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New social bandits? A comparative analysis of gangsterism in the Western and Eastern Cape provinces of South Africa

Criminology & Criminal Justice ◽

10.1177/1748895817750436 ◽

2018 ◽

Vol 19 (2) ◽

pp. 179-196

Author(s):

Theodore Petrus ◽

Irvin Kinnes

Keyword(s):

South Africa ◽

Comparative Analysis ◽

Social Contexts ◽

Effective Intervention ◽

Gang Violence ◽

Western Cape ◽

Eastern Cape ◽

The Social

Gang violence has been extensively highlighted as an issue of national concern in South Africa. Gangs also pose concerns about the social contexts of the communities in which they are found. The Western Cape and Eastern Cape provinces have had the most prolific occurrences of gangsterism. Here gangs have demonstrated unique characteristics that set them apart from gangs in other areas. This article examines the context of gangsterism in the selected provinces by means of a comparative analysis. The purpose is to provide some strategies for effective intervention. The discussion also interrogates how or why intervention efforts may have failed and what could be improved in order to strengthen the chances of success of future interventions in affected communities.

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Evaluation of the Serologic Cross-Reactivity between Transmissible Gastroenteritis Coronavirus and Porcine Respiratory Coronavirus Using Commercial Blocking Enzyme-Linked Immunosorbent Assay Kits

mSphere ◽

10.1128/msphere.00017-19 ◽

2019 ◽

Vol 4 (2) ◽

Cited By ~ 4

Author(s):

Ronaldo Magtoto ◽

Korakrit Poonsuk ◽

David Baum ◽

Jianqiang Zhang ◽

Qi Chen ◽

...

Keyword(s):

Culture Medium ◽

Large Deletion ◽

Cross Reactivity ◽

Enzyme Linked Immunosorbent Assay ◽

Transmissible Gastroenteritis Virus ◽

Serum Samples ◽

Serological Tests ◽

Transmissible Gastroenteritis ◽

Respiratory Coronavirus ◽

Porcine Respiratory

ABSTRACTThis study compared the performances of three commercial transmissible gastroenteritis virus/porcine respiratory coronavirus (TGEV/PRCV) blocking enzyme-linked immunosorbent assays (ELISAs) using serum samples (n = 528) collected over a 49-day observation period from pigs inoculated with TGEV strain Purdue (n = 12), TGEV strain Miller (n = 12), PRCV (n= 12), or with virus-free culture medium (n = 12). ELISA results were evaluated both with “suspect” results interpreted as positive and then as negative. All commercial kits showed excellent diagnostic specificity (99 to 100%) when testing samples from pigs inoculated with virus-free culture medium. However, analyses revealed differences between the kits in diagnostic sensitivity (percent TGEV- or PRCV-seropositive pigs), and all kits showed significant (P < 0.05) cross-reactivity between TGEV and PRCV serum antibodies, particularly during early stages of the infections. Serologic cross-reactivity between TGEV and PRCV seemed to be TGEV strain dependent, with a higher percentage of PRCV-false-positive results for pigs inoculated with TGEV Purdue than for TGEV Miller. Moreover, the overall proportion of false positives was higher when suspect results were interpreted as positive, regardless of the ELISA kit evaluated.IMPORTANCECurrent measures to prevent TGEV from entering a naive herd include quarantine and testing for TGEV-seronegative animals. However, TGEV serology is complicated due to the cross-reactivity with PRCV, which circulates subclinically in most swine herds worldwide. Conventional serological tests cannot distinguish between TGEV and PRCV antibodies; however, blocking ELISAs using antigen containing a large deletion in the amino terminus of the PRCV S protein permit differentiation of PRCV and TGEV antibodies. Several commercial TGEV/PRCV blocking ELISAs are available, but performance comparisons have not been reported in recent research. This study demonstrates that the serologic cross-reactivity between TGEV and PRCV affects the accuracy of commercial blocking ELISAs. Individual test results must be interpreted with caution, particularly in the event of suspect results. Therefore, commercial TGEV/PRCV blocking ELISAs should only be applied on a herd basis.

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Human herpes virus 8 antibodies in HIV-positive patients in Surabaya, Indonesia

Infectious Disease Reports ◽

10.4081/idr.2020.8746 ◽

2020 ◽

Author(s):

Devi Oktafiani ◽

Ni Luh Ayu Megasari ◽

Elsa Fitriana ◽

Nasronudin ◽

Maria Inge Lusida ◽

...

Keyword(s):

Drug Users ◽

Sandwich Elisa ◽

Human Herpesvirus ◽

Intravenous Drug ◽

Enzyme Linked Immunosorbent Assay ◽

Hiv Positive ◽

Intravenous Drug Users ◽

Serum Samples ◽

Serological Tests ◽

Human Herpes Virus 8

Background: Human herpesvirus 8 (HHV-8) infection is etiologically related to Kaposi’s sarcoma. Antibodies directed against HHV-8 can be detected in 80%–95% of HIV-seropositive patients with KS. HHV-8 serological tests have been done in several countries in Southeast Asia such as Malaysia, and Thailand however no serological data is available in Indonesia. This study was to examine the presence of HHV-8 antibodies in HIV-positive patients in Surabaya, Indonesia. Material and methods: Ninety-one serum samples were collected from HIV-positive patients in Surabaya, Indonesia. Human immunodeficiency virus-positive serum samples were collected from 10 homosexual men, 25 intravenous drug users (IVDUs) and 56 heterosexuals. Serums were then tested for the presence of HHV-8 antibody by using sandwich ELISA (Abbexa Ltd, Cambridge, UK). Results: The total of 91 HIV-infected were testing with antibodies to HHV-8 using enzyme-linked immunosorbent assay. Antibodies of HHV-8 were detected in 7/91 (7.7%) of the samples. According to a gender, six men (85.7%) and a women (14.3%) were positive of HHV-8 antibodies. No correlation regarding the gender and age from this study. The antibodies of HHV-8 was detected among intravenous drug users (IVDUs) men 5/7 (42.8%) and 2/7 (28.6%) from homosexual and heterosexual, respectively. Conclusion: This study found the presence of HHV-8 antibodies in 7.7% of patients in Surabaya, Indonesia. This finding was higher more than Southeast Asian countries. The patients with a positive result could suggest measures to prevent HHV-8 infection.

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Detection of bluetongue virus antibodies in sheep from Paraná, Brazil

Semina Ciências Agrárias ◽

10.5433/1679-0359.2020v41n3p879 ◽

2020 ◽

Vol 41 (3) ◽

pp. 879

Author(s):

Maria Carolina Ricciardi Sbizera ◽

Luiz Fernando Coelho da Cunha Filho ◽

Michele Lunardi ◽

Simone Fernanda Nedel Pertile ◽

Thais Helena Constantino Patelli ◽

...

Keyword(s):

Bluetongue Virus ◽

Animal Health ◽

Enzyme Linked Immunosorbent Assay ◽

Test Results ◽

Serum Samples ◽

Agar Gel ◽

Serological Tests ◽

High Occurrence ◽

Predominant Factor ◽

World Organization

Bluetongue (BT) is an infectious and non-contagious disease caused by bluetongue virus (BTV) belonging to the genus Orbivirus. It is transmitted by a hematophagous vector, Culicoides sp., to ruminants, particularly to sheep, which are most susceptible to this disease. The main serological tests are agar gel immunodiffusion (AGID), which is recommended by the World Organization for Animal Health (OIE), and the competitive enzyme-linked immunosorbent assay (cELISA), which has the advantage of no cross-reaction with other orbiviruses. The aim was to compare the results of these two tests by conducting them on sera collected from sheep in the state of Paraná, Brazil. From March to October 2017, serum samples were collected from 270 sheep from 10 farms in six mesoregions of Paraná. The samples were subjected to AGID and cELISA to detect antibodies against BTV. Based on the test results, we classified the sheep as low, moderate, and high occurrence. The results demonstrated that 64.81% (175/270) of the sheep were seropositive through the cELISA test, showing a high occurrence, and 41.11% (111/270) were seropositive through the AGID test, indicating a moderate occurrence. The concordance between the tests was moderate (0.51) as determined by the Kappa coefficient. Among the studied farms, 90% (9/10) presented at least one seropositive sheep, and the number of animals tested positive by the cELISA test was higher than those by the AGID test. Favorable climate, which favors the presence and multiplication of the culicoid vector and the occurrence of infection, was the biggest predominant factor responsible for the obtained results. The low occurrence in farms with milder climate suggest that the presence of antibodies also occurs due to the low pathogenicity of circulating serotypes in the different mesoregions studied. It is concluded that BTV infection is present in the sheep herds in Paraná, and the occurrence was moderate detected by AGID test and high detected by cELISA test.

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