Comparison of two enzyme immunoassays for the detection of Haemonchus contortus infections in sheep

Two enzyme-linked immunosorbent assays (ELISA) using either excretory/secretory (ES) products or crude somatic antigens (CSA) of adult Haemonchus contortus were compared for their ability to detect antibodies against H. contortus in sheep. Serum samples obtained from a group of 32 H. contortus mono-infected sheep were tested in the two ELISAs and the obtained data were compared with the results of the faecal examinations of these sheep. The first sheep became patent 3 weeks post infection (p.i.) and all sheep had positive egg counts at week 5 p.i. The first antibodies against H. contortus were detected 1 week p.i. and all sheep were found positive by both ELISAs at week 4 p.i. Using sera from a large number of H. contortus-infected sheep a difference in sensitivity between the ES ELISA (97.7%) and the CSA ELISA (89.2%) was found. The specificity of each assay was determined by testing sera obtained from sheep with mono-infections of H. contortus, Trichostrongylus colubriformis, Trichostrongylus vitrinus, Ostertagia circumcincta, Nematodirus battus, Cooperia curticei, Fasciola hepatica, Taenia ovis or Eimeria spp. The specificity of the ES ELISA was 87.2%, whereas the specificity of the CSA ELISA was 82.7

Nuancing stigma through ethnography: The case of cutaneous leishmaniasis in Suriname

Health-related stigma and its dramatic consequences for those stigmatized have long been a crucial concern for public health authorities globally. However, before concluding that stigma spoils the lives of people with a particular disease or disability and is a major obstacle to obtaining/providing adequate health care, it is necessary to first determine whether there is actual stigmatization related to the condition concerned. The purpose of this article is to nuance the concept of stigma through a detailed ethnographic exploration of the experiences and views of patients and others affected by the parasitic skin disease cutaneous leishmaniasis (CL) in Suriname, South America. Qualitative data on the perceptions, treatment and illness experiences of CL in Suriname was collected in 2009 and 2010 among 205 CL patients at the Dermatology Service in the capital city Paramaribo, and among 321 people in different rural hinterland villages. The exploration reveals the complex and sometimes confusing statements of patients and observers of social reactions to the disease. The authors conclude that – in contrast to other societies – CL is not generally a stigmatized disease in Suriname (though this is not to deny that stigmatization may occur occasionally). Over the past decades, the concepts of stigma and stigmatization have been abundantly theorized. But when theory drifts away from ethnographic evidence, it may turn into imprecise popular speech. In this article, we warn against inflation of the term stigma and show, through an in-depth qualitative description of reactions to symptoms of CL in Suriname, why negative reactions may not necessarily entail stigma

Molecular diagnosis of malaria in the field: development of a novel 1-step nucleic acid lateral flow immunoassay for the detection of all 4 human Plasmodium spp. and its evaluation in Mbita, Kenya

Microscopy is frequently used for malaria diagnosis, but at low parasitemia, it becomes less sensitive and time consuming. Molecular tools allow for specific/sensitive diagnosis, but current formats, such as polymerase chain reaction (PCR) combined with gel electrophoresis and real-time PCR assays, are difficult to implement in resource-poor settings. Development of a simple, fast, sensitive, and specific detection system, nucleic acid lateral flow immunoassay (NALFIA) for amplified pan-Plasmodium PCR products, is described. The NALFIA lower detection limit is 0.3 to 3 parasites/¿L, 10-fold more sensitive than gel electrophoresis analysis. Evaluating 650 clinically suspected malaria cases with the pan-Plasmodium assay under field conditions (rural Kenya) revealed that NALFIA detected more positives than microscopy (agreement, 95%; ¿ value = 0.85), and there was an excellent agreement between gel electrophoresis and NALFIA (98.5%; ¿ value = 0.96). In conclusion, NALFIA is more sensitive than microscopy and a good alternative to detect PCR products while circumventing using electricity or expensive equipment, making NALFIA the 1st step toward molecular field diagnosis

Molecular diagnosis of malaria in the field: development of a novel 1-step nucleic acid lateral flow immunoassay for the detection of all 4 human Plasmodium spp. and its evaluation in Mbita, Kenya

Microscopy is frequently used for malaria diagnosis, but at low parasitemia, it becomes less sensitive and time consuming. Molecular tools allow for specific/sensitive diagnosis, but current formats, such as polymerase chain reaction (PCR) combined with gel electrophoresis and real-time PCR assays, are difficult to implement in resource-poor settings. Development of a simple, fast, sensitive, and specific detection system, nucleic acid lateral flow immunoassay (NALFIA) for amplified pan-Plasmodium PCR products, is described. The NALFIA lower detection limit is 0.3 to 3 parasites/¿L, 10-fold more sensitive than gel electrophoresis analysis. Evaluating 650 clinically suspected malaria cases with the pan-Plasmodium assay under field conditions (rural Kenya) revealed that NALFIA detected more positives than microscopy (agreement, 95%; ¿ value = 0.85), and there was an excellent agreement between gel electrophoresis and NALFIA (98.5%; ¿ value = 0.96). In conclusion, NALFIA is more sensitive than microscopy and a good alternative to detect PCR products while circumventing using electricity or expensive equipment, making NALFIA the 1st step toward molecular field diagnosis

A magneto-optic route toward the in vivo diagnosis of malaria: preliminary results and preclinical trial data

We report the development of magneto-optic technology for the rapid quantitative diagnosis of malaria that may also be realizable in a noninvasive format. Hemozoin, the waste product of malarial parasitic action on hemoglobin, is produced in a form that under the action of an applied magnetic field gives rise to an induced optical dichroism characteristic of the hemozoin concentration. Here we show that precise measurement of this induced dichroism may be used to determine the level of malarial infection because this correlates, albeit in a complex manner throughout the infection cycle, with the concentration of hemozoin in the blood and tissues of infected patients. Under conservative assumptions for the production of hemozoin as a function of parasitemia, initial results indicate that the technique can match or exceed other current diagnostic techniques. The validity of the approach is confirmed by a small preliminary clinical trial on 13 patients, and measurements on live parasitized cells obtained from in vitro culture verify the possibility of producing in vivo diagnostic instrumentation