Immunochromatographic Rapid Diagnostic Tests Research Articles

Investigation of rotavirus and enteric adenovirus antigens in children between 0-14 years old

Acute gastroenteritis (AGE) is an important cause of mortality and morbidity, especially in children. Rotavirus, norovirus, and adenovirus are the most common viral AGE agents in Turkey. We aimed to investigate of rotavirus and adenovirus antigens in children between 0-14 years old with acute gastroenteritis admitted to the Bolu Abant Ýzzet Baysal University Training and Research Hospital. Rotavirus and adenovirus antigens were investigated by a combo rapid immunochromatographic diagnostic test (Eco test®, United Kingdom) in a total of 2,675 stool samples. One or more viruses were detected in 238 (8.9%) stool samples. Rotavirus antigen was detected in 191 (7.14%) stool specimens and adenovirus antigen were detected in 47 (1.75%) stool specimens. Both virus antigens were detected positive in 13 (6.8%) the stool samples. The detected rotavirus antigen positivity was higher under the age of 5 than other age groups; a statistically significant difference was found between age groups (p< 0.05; p< 0.00). In conclusion, rotavirus and adenovirus-associated AGE were most commonly found in the age group between 0–5 in this study. Also, the prevalence rates of viral AGE were found to be lower in the authors’ region when compared to other regions, probably due to the higher rates of rotavirus vaccination.

1655. Performance of Molecular and Serologic Tests for the Diagnosis of Scrub Typhus

BackgroundDiagnosis of scrub typhus, caused by the bacterium Orientia tsutsugamushi, is challenging because of the overlap of its nonspecific symptoms with other infections coupled with the lack of sufficient data on the performance of diagnostic tests. Early diagnosis of scrub typhus is crucial to improve outcomes and this study evaluated the diagnostic performance of various tests.MethodsAdult patients with acute febrile illness and manifestations suggestive of scrub typhus confirmed by positive PCR in the blood or eschar were characterized as cases. Patients with acute febrile illness and a confirmed alternate etiology such as culture-confirmed typhoid, smear/PCR positive for malaria, PCR/NS1 antigen positive for dengue, PCR positive for influenza, PCR/MAT positive for leptospirosis, PCR positive for spotted fever were characterized as controls with other infections. The healthy controls consisted of subjects from the same geographic region. We performed the following tests on blood samples for scrub typhus and calculated the sensitivity, specificity, positive predictive value, and negative predictive value: (1) Quantitative PCR using 47 kDa gene (qPCR); (2) Conventional PCR using 56kDa gene (cPCR); (3) Loop-mediated isothermal amplification assay (LAMP assay); (4) Immunofluorescence assay (IFA); (5) Enzyme-linked immunosorbent assay (ELISA); (6) Weil–Felix test (WF test); and (7) Immunochromatographic Rapid Diagnostic Test (RDT).ResultsAmong the 302 participants, 152 had confirmed scrub typhus (cases) and 150 were controls. ELISA and RDT detecting IgM antibodies had excellent discriminative potential with sensitivities and specificities of 94%, 93% and 92%, 93%, respectively. False-positive IgM serology was observed with spotted fever and leptospirosis. The sensitivity and specificity of IFA were found to be 80% and 85%, respectively. qPCR exhibited excellent sensitivity (96%) and perfect specificity.ConclusionELISA and RDT detecting IgM antibodies have excellent sensitivity and specificity while the sensitivity of IFA is suboptimal for the diagnosis of scrub typhus. Given its perfect specificity and superior sensitivity, qPCR is preferred for diagnostic confirmation in reference laboratories.Disclosures All authors: No reported disclosures.

Rapid immunochromatographic tests for the diagnosis of chronic Chagas disease in at-risk populations: A systematic review and meta-analysis.

BackgroundDespite of a high disease burden, mainly in Latin America, Chagas disease (CD) is underdiagnosed and undertreated. Rapid diagnostic tests (RDTs) might improve the access to diagnosis. The aim of this study is to review the accuracy of commercially available RDTs used in field conditions for the diagnosis of chronic CD in populations at risk, in endemic and non-endemic countries.Methods/Principal findingsWe undertook a comprehensive search of the following databases: PubMed, SCOPUS, LILACS (last up-date on the 01st July, 2017), without language or date limits. Non-electronic sources have been also searched. This review included clinical studies with cohort recruitment of individuals at risk of T. cruzi exposure, without age limits; adequate reference standards for the diagnosis of CD. We excluded case-control studies and those testing RDTs during acute CD. Data on test accuracies were pooled through a bivariate random-effects model. Only one index test was evaluated separately. Geographical area, commercial brand, disease prevalence, study size, and risk of bias were explored as possible source of heterogeneity. Values of sensitivity and specificity were computed to obtain summary positive/negative likelihood ratios, and summary diagnostic odds ratio. Ten studies were included on six different immunochromatographic RDTs. The pooled sensitivity and specificity of the RDTs resulted 96.6% (95% CI 91.3–98.7%) and 99.3% (95% CI 98.4–99.7%), respectively. Test accuracy was particularly good in endemic areas (98.07%/99.03% of sensitivity/specificity, respectively). One test (Stat-Pak) showed an overall sensitivity of 97% (95% CI 87.6–99.3) and specificity of 99.4% (95% CI 98.6–99.8).Conclusions/SignificanceRDTs demonstrated to be sufficiently accurate to recommend their use for screening in endemic areas, even as stand-alone tests. This approach might increase the accessibility to the diagnosis. However, an additional confirmatory test in case of positive result remains a prudent approach.

Parasite-based confirmation of malaria with rapid diagnostic tests: Challenges and Advantages

The key to effective case management of malaria is prompt and accurate diagnosis of malaria which is necessary to prevent morbidity and mortality. Accurate and practical malaria diagnostic such as immunochromatographic rapid diagnostic test can avert unnecessary treatments and save lives. Malaria presents a diagnostic challenge in most tropical countries. The urgency and importance of obtaining results quickly from the examination of blood samples from patient with suspected malaria is possible with the introduction of rapid malaria diagnostic test. Rapid diagnostic tests are useful in guiding therapeutic intervention, can be accessible to rural and urban populations, easy to perform and to interpret, affordable, requires no sophicated equipment and prompt treatment of malaria. The use of rapid diagnostic test in the case management of malaria has a lot of challenges which includes: persistent of histidine rich protein 2 in circulation after therapy and parasite death, effect of genetic diversity, lack of quality control on microscopy examination, poor transportation and storage condition, poor regulatory mechanism, lot-to-lot variation, parasite density and lack of extensive training prior to the use of rapid diagnostic test and supervision.

Prevalence of malaria among blood donors in blood bank, Jhalawar Hospital &amp; Medical College Society, Jhalawar, Rajasthan

Introduction: Transfusion Transmitted Malaria (TTM) is the great concern in endemic countries. Transmission of malaria by blood transfusion was one of the first recorded incidents of transfusion transmitted infection. The drugs and cosmetic act in India mandates the testing of all blood donations for human immunodeficiency virus (HIV) hepatitis B surface antigen (HbsAg), hepatitis C virus(HCV), malaria and syphilis. The present study aims to determine the prevalence of malarial among voluntary and replace­ment blood donors in Blood Bank, Jhalawar Hospital &amp; Medical college society, Jhalawar, Rajasthan. Material and Methods: A retrospective review of donors record covering the period between Jan 2017 to Dec 2017 at Blood Bank, Jhalawar Hospital &amp; Medical college society, Jhalawar, Rajasthan, India. The blood samples were then obtained by standard procedures of venepuncture. Malarial parasites were screened by microscopy (peripheral blood smear) and rapid Antigen card detection in blood bank. The study detected the presence of malaria parasites in donated blood units. Results: 5 out of 16495 donor population were positive(Prevalence 0.03%) on Immunochromatographic rapid diagnostic test for malarial antigen detection (Rapid Antigen Card Test). Conclusion: Blood donors in Blood Bank, Jhalawar Hospital &amp; Medical college society, Jhalawar, Rajasthan, India have a 0.03% prevalence and voluntary donations are safer as compared to replacement donation. By strict donor selection, proper donor testing and post testing counselling,the rate of TTM can be further minimized.

The Unknown Nature of the Antigen in the Direct Agglutination Test for Visceral Leishmaniasis Hampers Development of Serodiagnostic Tests.

.Current diagnostic tests for visceral leishmaniasis (VL) are either not adapted for use in resource-poor settings or are insufficiently accurate in Eastern Africa. Only the direct agglutination test (DAT), based on whole Leishmania promastigotes, is highly reliable in all endemic regions, but its implementation is hampered by the need for a cold chain, minimal laboratory conditions, and long incubation times. Integrating the DAT antigen(s) in an immunochromatographic rapid diagnostic test (RDT) would overcome these disadvantages. Unfortunately, the identity of the DAT antigen(s) involved in the agglutination reaction is unknown. For this study, we reviewed all publications that might shed some light on this issue. We conclude that the DAT antigen is a mixture of Leishmania-specific epitopes of protein, carbohydrate, and lipid nature. To develop an accurate RDT for VL diagnosis in Eastern Africa, we suggest to complement the classical protein antigen discovery with approaches to identify carbohydrate and lipid epitopes.

Evaluation of a rapid immunochromatographic diagnostic test (RIDT) for diagnosis of rabies in samples from Argentina.

Rabies is a globally widespread zoonosis of viral origin that causes fatal encephalitis in humans and animals. In countries where rabies is endemic and there is a lack of well-equipped diagnostic laboratories, a rapid immunochromatographic diagnostic test (RIDT) for detection of rabies could be an indispensable tool. In this study we evaluated the limit of detection, as well as specificity and sensitivity of RIDT, compared to the standard fluorescent antibody test (FAT). A total of 174 samples were diagnosed by both RIDT and FAT. Fresh clinical samples, poorly conserved samples and brains in advanced state of decomposition generated under laboratory conditions were used to resemble field conditions. The sensitivity of RIDT was evaluated with CVS fixed strain of rabies virus (RABV), previously titrated in 21-day old albino mice and compared with the Reverse Transcription - Polimerase Chain Reaction (RT-PCR) technique in parallel. Additionally, the Mouse Inoculation Test (MIT) was used to perform the antigenic characterization of Rabies virus variants. The limit of detection of RIDT was 100 LD50 / 0.03 mL and its performance, as compared to that of FAT, showed a sensitivity of 97.96%, a specificity of 100% and a concordance by the Kappa test of 0.98 with 95% CI. RIDT provides results comparable to those of FAT and this test can be considered as an appropriate method under the field conditions, even in samples that are not suitable for FAT due to their state of decomposition.

Analytical performances of simultaneous detection of HIV-1, HIV-2 and hepatitis C- specific antibodies and hepatitis B surface antigen (HBsAg) by multiplex immunochromatographic rapid test with serum samples: A cross-sectional study

BackgroundThe HIV/HCV/HBsAg Triplex consists in manually performed, visually interpreted, lateral flow, immunochromatographic rapid diagnostic test simultaneously detecting in 15min human immunodeficiency virus (HIV)-1 and HIV-2 and hepatitis C virus (HCV)- specific antibodies (Ab) (IgG and IgM) and hepatitis B virus (HBV) surface antigen (HBsAg) in serum, plasma and whole blood. MethodsA hospital-based cross-sectional study was conducted on a prospective panel of serum samples from adult inpatients included from routine analysis irrespectively of age and sex, including 250 sera positive for HIV-1-specific Ab, 250 for HCV-specific Ab, 250 for HBsAg and 250 sera negative for HIV- and HCV- Ab and HBsAg, and from 110 HIV-2-infected patients living in Ivory Coast, according to the results obtained by the reference chemiluminiscent microparticle immunoassay (CMIA) Abbott Architect i2000SR analyzer (Abbott Diagnostic, Chicago, IL, USA). Among HCV-seropositive sera, 187 were positive for HCV RNA (chronic infection), whereas 63 were negative (resolved infection), respectively. Serum samples were further tested blindly by HIV/HCV/HBsAg Triplex according to manufacturers’ recommendations. ResultsHIV/HCV/HBsAg Triplex showed very high sensitivity and specificity, as well as excellent concordance with CMIA Abbott results, as shown in the Table. Lower sensitivity was observed only in individuals who had cleared their HCV infection (presence of HCV-specific Ab in absence of HCV RNA). The mean lower limit of HBsAg detection was 2.38±0.63 IU/ml. Erythrocytes-spiked serum samples gave similar results than serum samples. ConclusionsAdvantages of HIV/HCV/HBsAg Triplex for HIV-1, HIV-2, HCV and HBV include the requirement for less overall specimen volume, fewer finger-sticks if capillary whole blood is used, cost savings through lower cost per virus tested, improved patient flow with results for multiple viruses available at the same time, overall service delivery efficiencies with less time required per infected patient; and patient benefits from fewer visits and lower cost associated with each clinic attendance. The screening of chronic HIV, HCV and HBV by multiplex HIV-1/HIV-2/HCV/HBsAg Triplex may improve the “cascade of screening” and quite possibly linkage-to-care with reduced cost.

Laboratory evaluation of immunochromatographic rapid diagnostic tests for cholera in Haiti

BackgroundRapid diagnostic tests (RDT) for cholera are promising tools for detecting cholera in areas with limited laboratory infrastructure. However, evidence on the characteristics of the many available RDTs is scarce, and their use has been limited by suboptimal performance. We evaluated the performance characteristics of three cholera RDTs from Span Diagnostics, Artron Laboratories, and Standard Diagnostics in a regional laboratory in Haiti.Methodology/Principal findingsWe retrospectively reviewed records from May 2014 to October 2015 of a laboratory-based surveillance program for Vibrio cholerae at Hôpital Saint-Nicolas in Saint-Marc, Haiti. We compared the results of 511 Crystal VC, 129 Artron and 451 SD Bioline RDTs to bacterial culture as the gold standard. Of 905 cultures, 477 (52.7%) were positive for V. cholerae O1, of which 27.7% were serotype Inaba. No cultures grew V. cholerae O139. Sensitivity and specificity of Crystal VC were 98.6% (95%CI: 96.5%-99.6%) and 71.1% (95%CI: 64.7%-76.9%), respectively. Artron demonstrated a sensitivity of 98.6% (95%CI: 92.7%-100%) and specificity of 69.1% (95%CI: 55.2%-80.9%). SD Bioline demonstrated a sensitivity of 81.1% (95%CI: 75.6%-85.8%) and specificity of 92.8% (95%CI: 88.4%-95.9%). Crystal VC and Artron frequently showed false positive O139 bands, whereas none were seen with SD Bioline.Conclusions/SignificanceThere is significant variation in the performance of different cholera diagnostic RDTs. Artron and Crystal VC RDTs have high sensitivity and low specificity, while SD Bioline RDT has low to moderate sensitivity and high specificity when performed by laboratory technicians in Haiti. Study limitations included its retrospective design. The suboptimal characteristics of these tests limit their use as clinical point-of-care tests; however, they may be useful in outbreak response, surveillance, and research in resource-limited settings.

Prevalence of Malaria in blood donor population from a tertiary care centre and effective donor notification and counselling policy

Background and ObjectiveTransfusion‐transmitted malaria is of great concern in endemic countries. From 1940, the Drugs and Cosmetic Act in India mandates the testing of all blood donations for human immunodeficiency virus (HIV), hepatitis B surface antigen (HbsAg), hepatitis C virus (HCV), malaria and syphilis. The present study was undertaken to assess the prevalence of malaria among blood donors and to summarize our experience with the notification algorithm that was developed for infected donors.Materials and MethodsRecords of all eligible donors, which were collected between 2011 and 2015, were analysed for the prevalence of malaria. Malaria screening was performed using by WHO‐approved immunochromatographic rapid diagnostic test (RDT) (Malascan®; Zephyr Biomedicals, India) for malarial antigen and confirmed by thick and thin blood smear. Those testing positive for malaria were called for post‐test counselling.ResultsA total of 108184 blood donors donated during the analysed period. Twenty‐six donors (0·024%) tested positive for malarial antigen by RDT. One (3·8%) of the 18 donors with double band on RDT showed the presence of mixed infection (Plasmodium vivax and Plasmodium falciparum). Fifteen (83·3%) donors were infected with P. falciparum. In the remaining two (11·1%) positive samples, further analysis by microscopy failed to find any evidence of malaria. There were eight non‐falciparum cases of P. vivax. Twenty‐one (80·8%) infected donations were avoided by post‐test counselling strategy as these donors underwent treatment prior to scheduling their next blood donation.ConclusionBlood donors in our region have a 0·024% prevalence of malaria. With proper donor testing, notification and post‐test counselling the rate of TTM can be further minimized.

Non-protective immunity against tetanus in primiparous women and newborns at birth in rural and urban settings in Ibadan, Nigeria.

IntroductionNigeria remains among the few countries that are yet to achieve eradication of neonatal tetanus in the world despite the availability of an effective vaccine. This study investigated immunity against tetanus in primiparous mothers and neonates at birth, and identified associated factors.MethodsThis cross-sectional study involved consecutive selection of 244 primiparous mother-neonate pairs (119 from rural areas, 125 from urban areas, 137 male neonates and 107 female neonates) delivered at primary healthcare facilities in Ibadan, Nigeria. Socio-demographic characteristics, obstetric history, immunisation and birthweight were obtained from mothers by interview. A validated immunochromatographic rapid diagnostic test kit was used to test for immunity against tetanus. Positive and negative results were interpreted as protective immunity against tetanus (PIaT) and non-protective immunity against tetanus (NPIaT), respectively. Data were analysed using descriptive statistics, Chi-square and logistic regression at p = 0.05.ResultsThe mean age of mothers was 27.9±3.4 years (range: 20-33) and median birthweight was 2700g (range: 1760-3300). Of the 244 mothers, 198 (81.1%) received at least two doses of tetanus toxoid injection during pregnancy and prevalence of NPIaT and PIaT was 28.7% and 71.3%, respectively. The prevalence of PIaT was significantly higher among mothers in urban areas (n= 96; 80.7%) than rural (n=78; 62.4%), p<0.001.The prevalence of NPIaT among neonates was 36.5% (n= 89). Predictors of NPIaT among neonates were residence in rural LGA (OR = 2.22; 95% CI = 1.23-3.99) and maternal tetanus immunisation <2 doses (OR = 11.68; 95% CI = 4.05-21.75).ConclusionLack of protective immunity against tetanus among neonates of primiparous women in Ibadan is prevalent and a more conscientious enforcement of routine tetanus prevention practices is needed.

Novel molecular diagnostic tools for malaria elimination: a review of options from the point of view of high-throughput and applicability in resource limited settings.

As malaria transmission continues to decrease, an increasing number of countries will enter pre-elimination and elimination. To interrupt transmission, changes in control strategies are likely to require more accurate identification of all carriers of Plasmodium parasites, both symptomatic and asymptomatic, using diagnostic tools that are highly sensitive, high throughput and with fast turnaround times preferably performed in local health service settings. Currently available immunochromatographic lateral flow rapid diagnostic tests and field microscopy are unlikely to consistently detect infections at parasite densities less than 100 parasites/µL making them insufficiently sensitive for detecting all carriers. Molecular diagnostic platforms, such as PCR and LAMP, are currently available in reference laboratories, but at a cost both financially and in turnaround time. This review describes the recent progress in developing molecular diagnostic tools in terms of their capacity for high throughput and potential for performance in non-reference laboratories for malaria elimination.

Influence of Rheumatoid Factors and Bilirubin on the Sensitivity of Immunochromatographic Rapid Diagnostic Tests for HIV/AIDS and Hepatitis B in Cameroon

Influence of Rheumatoid Factors and Bilirubin on the Sensitivity of Immunochromatographic Rapid Diagnostic Tests for HIV/AIDS and Hepatitis B in Cameroon

Addressing Barriers to the Development and Adoption of Rapid Diagnostic Tests in Global Health.

Immunochromatographic rapid diagnostic tests (RDTs) have demonstrated significant potential for use as point-of-care diagnostic tests in resource-limited settings. Most notably, RDTs for malaria have reached an unparalleled level of technological maturity and market penetration, and are now considered an important complement to standard microscopic methods of malaria diagnosis. However, the technical development of RDTs for other infectious diseases, and their uptake within the global health community as a core diagnostic modality, has been hindered by a number of extant challenges. These range from technical and biological issues, such as the need for better affinity agents and biomarkers of disease, to social, infrastructural, regulatory and economic barriers, which have all served to slow their adoption and diminish their impact. In order for the immunochromatographic RDT format to be successfully adapted to other disease targets, to see widespread distribution, and to improve clinical outcomes for patients on a global scale, these challenges must be identified and addressed, and the global health community must be engaged in championing the broader use of RDTs.

Comparative Study of Malaria Prevalence among Travellers in Nigeria (West Africa) Using Slide Microscopy and a Rapid Diagnosis Test.

Malaria is a major disease in Africa and leads to various public health problems. A study was carried out at the Aviation Medical Clinic Laboratory, Murtala Mohammed Airport, Ikeja, Lagos State, Nigeria, in 2014. The work aimed to determine the prevalence of malaria among patients attending the laboratory. Blood samples were therefore collected from 51 patients and subjected to both blood smear microscopy and a rapid immunochromatographic diagnostic test (SD BIOLINE Malaria Ag) for detection of, respectively, malaria parasites and antigens. At the end of the study, 22% of the patients were detected positive by the microscopic examination while 9.8% were tested positive when using SD BIOLINE Malaria Ag. The outcomes of the study show a high prevalence of malaria at the airport. This represents a serious risk factor leading to a high likelihood of spread and occurrence of malaria in other countries including Western countries whereby the disease is nonendemic. It also pointed out that the blood smear microscopy seems to be better than Rapid Diagnosis Test (RDT) for malaria diagnosis.

IgG1 as a potential biomarker of post-chemotherapeutic relapse in visceral leishmaniasis, and adaptation to a rapid diagnostic test.

BackgroundVisceral leishmaniasis (VL), caused by protozoa of the Leishmania donovani complex, is a widespread parasitic disease of great public health importance; without effective chemotherapy symptomatic VL is usually fatal. Distinction of asymptomatic carriage from progressive disease and the prediction of relapse following treatment are hampered by the lack of prognostic biomarkers for use at point of care.Methodology/Principal FindingsAll IgG subclass and IgG isotype antibody levels were determined using unpaired serum samples from Indian and Sudanese patients with differing clinical status of VL, which included pre-treatment active VL, post-treatment cured, post-treatment relapsed, and post kala-azar dermal leishmaniasis (PKDL), as well as seropositive (DAT and/or rK39) endemic healthy controls (EHCs) and seronegative EHCs. L. donovani antigen-specific IgG1 levels were significantly elevated in relapsed versus cured VL patients (p<0.0001). Using paired Indian VL sera, consistent with the known IgG1 half-life, IgG1 levels had not decreased significantly at day 30 after the start of treatment (p = 0.8304), but were dramatically decreased by 6 months compared to day 0 (p = 0.0032) or day 15 (p<0.0001) after start of treatment. Similarly, Sudanese sera taken soon after treatment did not show a significant change in the IgG1 levels (p = 0.3939). Two prototype lateral flow immunochromatographic rapid diagnostic tests (RDTs) were developed to detect IgG1 levels following VL treatment: more than 80% of the relapsed VL patients were IgG1 positive; at least 80% of the cured VL patients were IgG1 negative (p<0.0001).Conclusions/SignificanceSix months after treatment of active VL, elevated levels of specific IgG1 were associated with treatment failure and relapse, whereas no IgG1 or low levels were detected in cured VL patients. A lateral flow RDT was successfully developed to detect anti-Leishmania IgG1 as a potential biomarker of post-chemotherapeutic relapse.

KUPFFER CELLS: TARGETING FOR THE EFFECTIVE MANAGEMENT OF VISCERAL LEISHMANIASIS

Visceral leishmaniasis is a protozoan disease which infects the macrophages of body and Kupffer cells (KCs) in the liver resident macrophages, which constitute 80% of tissue macrophages of the body. KCs are the first cellular protective line in liver sinusoid, which come into contact with gut-derived pathogenic microbes, microbial debris and senescent erythrocytes and impede the exogenous materials by producing cytokines and directly phagocytosing and degrading them. Visceral leishmaniasis (VL) is a vector-borne disease and it is widely accredited that the frequency as well as transmission dynamics of VL is closely interrelated to socioeconomic, climatic, and environmental factors. Macrophages act so as to secrete IL-1, TNF and IL-6 at the time of injury and infection, and process and present antigen to help T cells. Mononuclear phagocytic system consists of monocytes circulating in the blood and macrophages in tissue. Macrophages are dispersed throughout the body and take up residence in some tissues. Human leishmanial infections may manifest in any of the four most common forms. Depending on the causative species, it can manifest as cutaneous leishmaniasis mucocutaneous leishmaniasis, visceral leishmaniasis or diffused cutaneous leishmaniasis. The cutaneous form of the disease accounts for more than 50% of new cases of leishmaniasis. The current method of VL diagnosis involves evaluating clinical symptoms that include fever for more than 2 week, the presence of splenomegaly and a positive serological rK39 immunochromatographic rapid diagnostic test (RDT). The rK39 RDT is used to detect the presence of antibodies against the Leishmania antigen K39 that contains a repetitive 39 amino acid sequence from the kinesin protein.

A Global Comparative Evaluation of Commercial Immunochromatographic Rapid Diagnostic Tests for Visceral Leishmaniasis

Poor access to diagnosis stymies control of visceral leishmaniasis (VL). Antibody-detecting rapid diagnostic tests (RDTs) can be performed in peripheral health settings. However, there are many brands available and published reports of variable accuracy. Commercial VL RDTs containing bound rK39 or rKE16 antigen were evaluated using archived human sera from confirmed VL cases (n = 750) and endemic non-VL controls (n = 754) in the Indian subcontinent (ISC), Brazil, and East Africa to assess sensitivity and specificity with 95% confidence intervals. A subset of RDTs were also evaluated after 60 days' heat incubation (37°C, 45°C). Interlot and interobserver variability was assessed. All test brands performed well against ISC panels (sensitivity range, 92.8%-100%; specificity range, 96%-100%); however, sensitivity was lower against Brazil and East African panels (61.5%-91% and 36.8%-87.2%, respectively). Specificity was consistently > 95% in Brazil and ranged between 90.8% and 98% in East Africa. Performance of some products was adversely affected by high temperatures. Agreement between lots and readers was good to excellent (κ > 0.73-0.99). Diagnostic accuracy of VL RDTs varies between the major endemic regions. Many tests performed well and showed good heat stability in the ISC; however, reduced sensitivity against Brazilian and East African panels suggests that in these regions, used alone, several RDTs are inadequate for excluding a VL diagnosis. More research is needed to assess ease of use and to compare performance using whole blood instead of serum and in patients coinfected with human immunodeficiency virus.

Evaluation of a rapid immunochromatographic diagnostic test for the detection of rabies from brain material of European mammals

The surveillance of rabies relies on investigations conducted on dead suspected animals or animals showing clinical signs suggestive of rabies. An immunochromatographic method based on lateral flow principle has been evaluated against a collection of brain samples mainly of European mammals including bats. The performance of this new test has been compared to the conventional gold standard methods: the fluorescent Antibody Test (FAT) and the Rapid Tissue Culture Infection Test (RTCIT). This test enabled the detection of various rabies strains belonging to rabies species 1, 5, 6 and 7 and demonstrated an overall specificity of 100% and a sensitivity of more than 88% when compared to FAT and RTCIT. A total agreement between the Rapid Immunochromatographic Diagnostic Test and conventional technique results have been obtained for European bat samples.

Seroprevalence of malaria in blood donors and multi-transfused patients in Northern India: Relevance to prevention of transfusion-transmissible malaria

Background:Transfusion-transmissible malaria (TTM) is a major concern in malaria endemic countries. A study was therefore conducted to know sero-prevalence of malaria in blood donors and the risk of TTM to multi-transfused patients at our hospital.Materials and Methods:Study subjects were: eligible blood donors (n = 1000), donors deferred due to history of fever in the last 3 months (n = 100), and multi-transfused patients (n = 200). Screening for malaria was done by slide microscopy, immunochromatographic rapid diagnostic test (RDT) for malaria antigen, and anti-malaria antibody by enzyme linked immunosorbent assay.Results:Malaria antibody prevalence in eligible donors and donors with history of fever, thalassemia patients, and in other multi-transfused patients was 16.9%, 22%, 6%, and 15%, respectively. None of the donors were positive for malaria on microscopic examination. None of the blood donors except one donor with history of fever, tested positive with RDT.Conclusion:Malaria antibody prevalence in blood donors at our center is high. As blood units donated by such donors have high-risk potential, special processing may be undertaken to reduce the risk of TTM.