The use of commercial immunoenzyme and latex preparations for the demonstration of human rotavirus antigens

The results of using enzyme immunoassay and latex preparations for the diagnosis of rotavirus gastroenteritis are presented. High effectiveness of the enzyme immunoassay system developed in the USSR with latex diagnostic agents, such as Rotalex (Orion Diagnostica, Finland), Slidex Rota Kit (BioMérieux, France), The Wellcome Rotavirus Latex Kit (Wellcome Foundation Ltd., Great Britain), 48-63% and 21-41% respectively, has been noted. The results of the comparison of the system developed in the USSR with Wellcozyme Rotavirus, an enzyme immunoassay system manufactured by Wellcome Foundation Ltd. (Great Britain), are practically comparable. The results of the block test and the confirmation test used for control indicate that the Soviet preparation is specific. Materials on the practical evaluation of the assay system at health institutions are presented. Good prospects for the use of this system in the diagnosis of rotavirus gastroenteritis, as well as in the realization of epidemiological surveillance on this infection, are substantiated.     

Screening adenoviruses in stool samples: evaluation of a genus-specific monoclonal antibody based enzyme immunoassay

To screen fecal samples for adenovirus antigens a genus-specific monoclonal antibody based enzyme immunoassay was developed. In a comparative analysis with commercial latex agglutination test, high sensitivity was demonstrated. The assay did not detect other viruses usually found in faeces suggesting its specificity. One hundred and eighty stool samples collected in Baranya County were tested and 13 (7.2%) of them showed reactivity. The application of our immunoassay combined with other, more sophisticated methods may help us to determine the serotype specificity of these adenovirus isolates and assess the importance of adenoviruses in viral gastroenteritis.     

Electron microscopy in the diagnosis of viral gastroenteritis in hospitalised children in the Czech Republic

Our study has been aimed at demonstrating the main role of viruses in the aetiology of acute gastroenteritis in children less than 5 years old and at pointing out the diagnostic potential of electron microscopy in the diagnosis of viral gastroenteritis. A prospective study was conducted to analyse the aetiology of diarrhoeal diseases in children less than 5 years of age admitted to the Department of Infectious Diseases between September 2006 and December 2008. All children were tested by faecal culture, latex agglutination and electron microscopy. A total of 832 children were included in the study. An aetiological agent was detected in 788 children (94.6 %). A bacterial aetiology was found in 22 (2.6 %) children and bacterial–viral co-infection was found in 146 (17.6 %) patients. The most frequent causative agents of gastroenteritis in children were viruses, which were detected in 620 (74.5 %) patients. The main causes of viral gastroenteritis were rotaviruses (detected in 410 children), followed by caliciviruses (42), coronaviruses (28), adenoviruses (19) and astroviruses (14). Dual viral infections were detected in 107 children, with rotavirus–calicivirus co-infection being the most common. Electron microscopy proved to be a more sensitive method in comparison with the latex agglutination test for the diagnosis of rotaviruses and adenoviruses. The major role of viruses in diarrhoeal diseases among children under 5 years of age in the Czech Republic has been confirmed. The diagnostic potential of electron microscopy, particularly in small outbreaks of gastroenteritis, was clearly shown.     

Large-scale validation of a latex agglutination test for diagnosis of tuberculosis

Large-scale validation of a simple latex agglutination test for the diagnosis of tuberculosis is described. Soluble antigens extracted from a non-pathogenic saprophytic mycobacterium, Mycobacterium w, which shares antigenic determinants with Mycobacterium tuberculosis, were covalently linked to carboxylated polystyrene latex beads. Batch to batch reproducibility of coated latex was ensured. Latex reagents were standardized to overcome non-specific agglutination. Reagents of the test are stable for 1 year at 4 degrees C. A total of 1,058 serum samples of pulmonary and extrapulmonary tuberculosis patients or patients with other pulmonary diseases and healthy controls living in endemic areas were tested. Sensitivity of 94% for pulmonary tuberculosis and 87% for extrapulmonary tuberculosis was obtained. Specificity is 92.2% for healthy controls and patients with other respiratory diseases. We conclude that the latex agglutination test can be utilized for mass screening for both pulmonary and extrapulmonary tuberculosis where diagnosis by existing methods is much more difficult.     

Comparison of ELISA with shell vial cell culture method for the detection of human rotavirus in fecal specimens

The aim of the study was to compare an enzyme immunoassay method with shell vial cell culture method for detection of rotavirus in fecal specimens. In addition, the correlation between laboratory results and clinical scores of patients with gastroenteritis was evaluated. A total of 219 fecal specimens from children (ages 3 weeks to 5 years) with acute gastroenteritis submitted to pediatric emergency room were evaluated by both ELISA and shell vial cell culture. A Vesikari score was used for assessing the severity of the illness. Among 219 stool samples tested, 107 (48.9%) were determined to be positive. Two specimens were positive by shell vial cell culture method while they were ELISA negative. According to these results the calculated sensitivity, specificity, PPV, and NPV of ELISA were 98.1%, 100%, 100%, and 98.2%, respectively. The mean severity score for the 107 episodes of rotavirus diarrhoea was 11.0 +/- 3.6 compared to 4.5 +/- 1.9 for the 112 episodes of non-rotavirus diarrhea in the same population. Our study indicates that ELISA, which is easier to perform, faster and cheaper than cell culture methods may be suitable for routine diagnosis of rotavirus infections. The severity of rotavirus positive gastroenteritis was significantly higher than that of rotavirus negative patients.     

The use of the latex agglutination reaction for the diagnosis of a Brucella infection

The authors have developed the optimum conditions for the preparation of antigenic diagnosticum based on latex manufactured in the USSR. To sensitize latex with the diameter of microspheres equal to 0.83 microns, Brucella polysaccharide was used in a dose of 100 micrograms/ml. As stabilizer, polyvinylpyrrolidone at a concentration of 0.1% was used. The specificity and sensitivity of the diagnosticum were studied in analysis of serum samples taken from 102 healthy donors and patients with infectious diseases of nonbrucellar etiology and from 120 patients with different forms of brucellosis. The specificity of the diagnosticum was found to be 94.1% and its sensitivity, 77.5%. Comparative study of the latex agglutination test with other serological tests showed that the former test is highly effective both in acute and chronic forms of the disease. A high degree of correlation between the agglutination test, Coombs' test, the passive hemagglutination test and the latex agglutination test was established (r = 0.83, 0.72 and 0.62, respectively).     

Evaluation of the usefulness for the latex agglutination test for serodiagnosis of Mycoplasma pneumoniae infections

The usefulness of latex agglutination test prepared in our laboratory for the diagnosis of M. pneumoniae infections was assessed. A total of 628 serum samples obtained from patients with respiratory tract infections were tested by complement fixation test and by latex test, from among them 274 serum samples were additionally tested by ELISA--Ig A/--IgG/--IgM and by immunoelectroprecipitation test. The highest sensitivity and specificity was displayed by the latex test in relation to ELISA when determining mycoplasmal antibodies of IgM class (respectively 82.1% and 89.6%) and to the complement fixation test (81.0% and 89.0%). Positive latex test results in our investigations were associated only with the presence of IgM antibodies and were not dependent on the IgA and IgG antibody classes. The latex agglutination test may be used in routine serodiagnosis of mycoplasmosis under condition that the results obtained in this test will be confirmed by the complement fixation test or ELISA.     

杭州地区腹泻儿童轮状病毒与腺病毒感染调查

目的分析不同季节及不同年龄段腹泻患儿感染轮状病毒(RV)与腺病毒(Eads)情况,为临床提供早期、快速、准确、可靠的依据,以便及时采取相应的治疗使患儿早日康复。方法采用杭州艾博医药有限公司提供的轮状病毒(A组)/腺病毒检测试剂盒(乳胶法),对2012年1月至2015年12月浙江省人民医院门诊和住院就诊的3 368例腹泻儿童粪便标本进行轮状病毒和腺病毒抗原检测。结果 3 368例腹泻儿童粪便中,RV阳性578例占17.16%,Eads阳性106例占3.15%。11月至次年1月为轮状病毒感染的高发月份,1~3岁为儿童感染的高发年龄;腺病毒感染阳性率低,呈散发性。结论杭州地区近年1~3岁婴幼儿的腹泻主要是由轮状病毒和腺病毒引起,其中轮状病毒感染率明显高于腺病毒,且有明显的季节性;而腺病毒感染呈散发流行,未表现出明显的季节性及年龄分布。     

Serological investigation of Theileria sergenti using latex agglutination test in South Korea

Theileria sergenti causes persistent theileriosis in cattle, characterized by fever and chronic anemia. Theileriosis causes losses in feed efficiency and growth retardation through cycling infections in endemic areas. Among several major proteins of T. sergenti merozoites, the surface protein p33 is reported to be the most immunogenic. In this study, we investigated the use of p33 as a diagnostic antigen in a latex agglutination test to monitor antibodies against T. sergenti. When compared with TaqMan polymerase chain reaction, the sensitivity and specificity of the latex agglutination test were 86.5 and 92.5%, respectively. An epidemiological survey using the latex agglutination test was conducted with 1,046 sera collected from 4 slaughterhouses and 2 individual pasture farms throughout South Korea; 27.3% of samples were seropositive, depending on the areas in which the cattle were raised. This study indicated that the latex agglutination test could be used as a convenient tool for epidemiological monitoring of T. sergenti infections in the field.     

Genotypes of rotavirus associated with acute gastroenteritis in Seoul, Korea

Acute viral gastroenteritis is one of the most common infectious diseases in infants and young children. Rotavirus is mainly important in childhood. The present study determined the detection rate, seasonality and G and P genotypes of rotaviruses in children hospitalized for acute gastroenteritis in Seoul, Korea in 2009. A total of 1,423 stool specimens were screened by ELISA for the presence of rotavirus antigens and the rotavirus-positive stools genotyped by RT-PCR. The G genotype was determined for 90% of samples (242/269) and the P genotype for 93.3% (251/269). During the study, 25 G-P combinations were detected with G1P[8] in 38.3% (n= 103) and G4P[6] in 5.9% (n= 16) cases. These data provided information on rotavirus in patients with acute gastroenteritis in Seoul, Korea and provided baseline data to motivate for the implementation of control measures for rotavirus disease.     

Molecular epidemiology and clinical characterization of group A rotavirus infections in Tunisian children with acute gastroenteritis

Rotaviruses are the most common cause of severe viral gastroenteritis in early childhood worldwide. Thus, the objectives of our study were to determine the molecular epidemiology and the clinical features of rotavirus gastroenteritis in Tunisia. Between January 2003 and April 2007, a prospective study was conducted on 788 stool samples collected from children under 12 years of age who were suffering from acute gastroenteritis. Rotavirus was detected by multiplex RT-PCR in 27% (n = 213) of samples, among them 79.3% (n = 169) cases were monoinfections. The frequency of rotavirus infections was significantly higher among inpatients (29%) than among outpatients (13%) (P < 0.001). The seasonal distribution of rotavirus diarrhea showed a winter peak, with an unusual peak from June to September. The mean duration of hospitalization was 6.5 ± 8.1 days and the mean age was 15.8 ± 22.8 months for rotavirus monoinfections. Fever, vomiting, abdominal pain, and dehydration were observed in 88, 98, 13, and 80 cases, respectively, in children with rotavirus monoinfections. G3P[8] (45.6%) and G1P[8] (23.9%) were the most common genotypes found in our study. The determination of rotavirus infection prevalence and the characterization of the rotavirus strains circulating will help us to better understand the molecular biology and epidemiology of the disease in our country.     

The use of latex agglutination tests for determining Campylobacter species

A comparison was made between three commercially available latex agglutination tests for the detection of Campylobacter. All tests showed clear agglutination with pure cultures of several Campylobacter strains in both the spiral and coccoid form. The Microscreen test was able to detect 10 times less cells than the Campyslide and Meritec tests. The latex tests were also applied to enrichment broth cultures of chicken products. Sixty-nine per cent of the Campylobacter positive enrichment broth cultures were positive with the Microscreen test. The Meritec test detected 63% of the positive samples. The Campyslide test detected only 15% of the positive samples and often showed non-specific agglutination.     

Household Catastrophic Healthcare Expenditure and Impoverishment Due to Rotavirus Gastroenteritis Requiring Hospitalization in Malaysia

Background

While healthcare costs for rotavirus gastroenteritis requiring hospitalization may be burdensome on households in Malaysia, exploration on the distribution and catastrophic impact of these expenses on households are lacking.

Objectives

We assessed the economic burden, levels and distribution of catastrophic healthcare expenditure, the poverty impact on households and inequities related to healthcare payments for acute gastroenteritis requiring hospitalization in Malaysia.

Methods

A two-year prospective, hospital-based study was conducted from 2008 to 2010 in an urban (Kuala Lumpur) and rural (Kuala Terengganu) setting in Malaysia. All children under the age of 5 years admitted for acute gastroenteritis were included. Patients were screened for rotavirus and information on healthcare expenditure was obtained.

Results

Of the 658 stool samples collected at both centers, 248 (38%) were positive for rotavirus. Direct and indirect costs incurred were significantly higher in Kuala Lumpur compared with Kuala Terengganu (US$222 Vs. US$45; p<0.001). The mean direct and indirect costs for rotavirus gastroenteritis consisted 20% of monthly household income in Kuala Lumpur, as compared with only 5% in Kuala Terengganu. Direct medical costs paid out-of-pocket caused 141 (33%) households in Kuala Lumpur to experience catastrophic expenditure and 11 (3%) households to incur poverty. However in Kuala Terengganu, only one household (0.5%) experienced catastrophic healthcare expenditure and none were impoverished. The lowest income quintile in Kuala Lumpur was more likely to experience catastrophic payments compared to the highest quintile (87% vs 8%). The concentration index for out-of-pocket healthcare payments was closer to zero at Kuala Lumpur (0.03) than at Kuala Terengganu (0.24).

Conclusions

While urban households were wealthier, healthcare expenditure due to gastroenteritis had more catastrophic and poverty impact on the urban poor. Universal rotavirus vaccination would reduce both disease burden and health inequities in Malaysia.     

Latex agglutination test for diagnosing pneumococcal pneumonia in children in developing countries.

OBJECTIVE--To prepare and assess the sensitivity and specificity of a latex agglutination test specific for the serotype of antigen in diagnosing pneumococcal pneumonia in Gambian children. DESIGN--Comparison of agglutination test specific for serotype with culture of blood and lung aspirates, countercurrent immunoelectrophoresis, and commercial latex agglutination tests in diagnosing pneumococcal pneumonia. Cross reaction studies and investigation of 102 control children to determine specificity of agglutination test specific for serotype. SETTING--General medical ward of Medical Research Council laboratories, The Gambia. PATIENTS--101 Gambian children aged between 2 months and 10 years admitted with severe pneumonia. INTERVENTIONS--Serum samples were boiled and treated with edetic acid, and urine samples were boiled and concentrated 25 times before testing. END POINT--A latex agglutination test specific for the serotype of pneumococcal antigen that is sensitive and highly specific for detecting pneumococcus in the urine of patients with pneumococcal pneumonia. MEASUREMENTS AND MAIN RESULTS--Concentrated urine samples from 16 of the 21 children (76%) with pneumococcal pneumonia established by results of culture of blood or lung aspirates gave a positive result with the agglutination test specific for serotype, whereas only four of the 102 urine samples obtained from control children without pneumonia gave positive results. The serotypes of antigens detected in the urine of children with pneumococcal pneumonia and the serotypes of pneumococci isolated from cultures of blood or lung aspirates were the same in all cases. CONCLUSIONS--When performed on urine samples the agglutination test specific for serotype has a high specificity and is more sensitive than culture of blood or lung aspirates, commercial agglutination tests, or countercurrent immunoelectrophoresis in identifying pneumococcal pneumonia. It is easy to use and should be especially useful in communities with limited laboratory facilities.     

多重RT-PCR用于临床检测三种胃肠炎病毒的研究

轮状病毒、诺瓦克病毒和星状病毒是引起病毒性胃肠炎的主要病原因子。研究采用JV12/JV13、P1/P2和Mon340/Mon348三对引物,建立了同时检测这3种病毒的多重RT-PCR技术,并应用于128份临床粪便样本的检测,检出轮状病毒62份(48.44%),诺瓦克病毒8份(6.25%),星状病毒11份(8.59%)。在灵敏度试验中,轮状病毒的检测灵敏度为5pg/mL、诺瓦克病毒和星状病毒的检测灵敏度均为50pg/mL。该研究所建立3种常见胃肠炎病毒的多重RT-PCR方法具有特异性强、灵敏度高的特点,可用于临床病原诊断和溯源。     

Comparative evaluation of whole blood D-dimer test to plasma D-dimer test for diagnosis of disseminated intravascular coagulation

Three rapid D-dimer test methods were compared for the diagnosis of acute disseminated intravascular coagulation (DIC). These were (a) SimpliRED, an autologous red cell agglutination assay. (b) DIMERTEST latex agglutination assay, containing monoclonal antibody DD-3B6/22(6), and (c) D-DI latex agglutination assay containing mouse anti-human D-dimer monoclonal antibodies. The D-DI latex method having higher sensitivity (100%) and specificity (81%) in clinically acute DIC was postulated as the gold standard and compared with the other two methods. The results suggest that D-DI latex agglutination assay containing mouse anti-human D-Dimer monoclonal antibodies are the better assay methods amongst all the three kits analyzed. It is advisable to look for the nature of the antibody used to coat the latex particles in plasma based kits. In emergency setting RBC kits may be of some use as rapid diagnosis is advantageous.