Evaluation of three commercially-available chikungunya virus immunoglobulin G immunoassays.

The emergence of chikungunya virus in the Americas means the affected population is at risk of developing severe, chronic, rheumatologic disease, even months after acute infection. Accurate diagnostic methods for past infections are essential for differential diagnosis and consequence management. This study evaluated three commercially-available chikungunya Immunoglobulin G immunoassays by comparing them to an in-house Enzyme-Linked ImmunoSorbent Assay conducted by the Centers for Disease Control and Prevention (Atlanta, Georgia, United States). Results showed sensitivity and specificity values ranging from 92.8% - 100% and 81.8% - 90.9%, respectively, with a significant number of false-positives ranging from 12.5% - 22%. These findings demonstrate the importance of evaluating commercial kits, especially regarding emerging infectious diseases whose medium and long-term impact on the population is unclear.

Evaluation of three commercially-available chikungunya virus immunoglobulin G immunoassays / Evaluación de tres inmunoensayos comercializados de inmunoglobulina G para el diagnóstico del virus del chikungunya

The emergence of chikungunya virus in the Americas means the affected population is at risk of developing severe, chronic, rheumatologic disease, even months after acute infection. Accurate diagnostic methods for past infections are essential for differential diagnosis and consequence management. This study evaluated three commercially-available chikungunya Immunoglobulin G immunoassays by comparing them to an in-house Enzyme-Linked ImmunoSorbent Assay conducted by the Centers for Disease Control and Prevention (Atlanta, Georgia, United States). Results showed sensitivity and specificity values ranging from 92.8% – 100% and 81.8% – 90.9%, respectively, with a significant number of false-positives ranging from 12.5% – 22%. These findings demonstrate the importance of evaluating commercial kits, especially regarding emerging infectious diseases whose medium and long-term impact on the population is unclear.

Como consecuencia de la aparición del virus del chikungunya en las Américas, la población afectada corre el riesgo de padecer reumatismos crónicos graves, aun meses después de la infección aguda. Es fundamental contar con métodos precisos para diagnosticar los antecedentes de la infección a fin de elaborar un diagnóstico diferencial y abordar las manifestaciones de la fase crónica. Se han estudiado tres inmunoensayos comercializados de detección de inmunoglobulinas G para el diagnóstico del chikungunya, comparándolos con el enzimoinmunoanálisis de adsorción (ELISA) propio. Los resultados señalan valores de sensibilidad del 92,8% al 100% y de especificidad del 81,8% al 90,9%, así como un número significativo de falsos positivos, de entre el 12,5% y el 22%.

Riparian rehabilitation planning in an urban-rural gradient: Integrating social needs and ecological conditions.

In the present context of global change and search for sustainability, we detected a gap between restoration and society: local communities are usually only considered as threats or disturbances when planning for restoration. To bridge this gap, we propose a landscape design framework for planning riparian rehabilitation in an urban-rural gradient. A spatial multi-criteria analysis was used to assess the priority of riversides by considering two rehabilitation objectives simultaneously-socio-environmental and ecological-and two sets of criteria were designed according to these objectives. The assessment made it possible to identify 17 priority sites for riparian rehabilitation that were associated with different conditions along the gradient. The double goal setting enabled a dual consideration of citizens, both as beneficiaries and potential impacts to rehabilitation, and the criteria selected incorporated the multi-dimensional nature of the environment. This approach can potentially be adapted and implemented in any other anthropic-natural interface throughout the world.

Evaluation of three commercially-available chikungunya virus immunoglobulin G immunoassays / Evaluación de tres inmunoensayos comercializados de inmunoglobulina G para el diagnóstico del virus del chikungunya

ABSTRACT The emergence of chikungunya virus in the Americas means the affected population is at risk of developing severe, chronic, rheumatologic disease, even months after acute infection. Accurate diagnostic methods for past infections are essential for differential diagnosis and consequence management. This study evaluated three commercially-available chikungunya Immunoglobulin G immunoassays by comparing them to an in-house Enzyme-Linked ImmunoSorbent Assay conducted by the Centers for Disease Control and Prevention (Atlanta, Georgia, United States). Results showed sensitivity and specificity values ranging from 92.8% - 100% and 81.8% - 90.9%, respectively, with a significant number of false-positives ranging from 12.5% - 22%. These findings demonstrate the importance of evaluating commercial kits, especially regarding emerging infectious diseases whose medium and long-term impact on the population is unclear.(AU)

RESUMEN Como consecuencia de la aparición del virus del chikungunya en las Américas, la población afectada corre el riesgo de padecer reumatismos crónicos graves, aun meses después de la infección aguda. Es fundamental contar con métodos precisos para diagnosticar los antecedentes de la infección a fin de elaborar un diagnóstico diferencial y abordar las manifestaciones de la fase crónica. Se han estudiado tres inmunoensayos comercializados de detección de inmunoglobulinas G para el diagnóstico del chikungunya, comparándolos con el enzimoinmunoanálisis de adsorción (ELISA) propio. Los resultados señalan valores de sensibilidad del 92,8% al 100% y de especificidad del 81,8% al 90,9%, así como un número significativo de falsos positivos, de entre el 12,5% y el 22%.(AU)

Measuring Haitian children's exposure to chikungunya, dengue and malaria.

OBJECTIVE: To differentiate exposure to the newly introduced chikungunya virus from exposure to endemic dengue virus and other pathogens in Haiti. METHODS: We used a multiplex bead assay to detect immunoglobulin G (IgG) responses to a recombinant chikungunya virus antigen, two dengue virus-like particles and three recombinant Plasmodium falciparum antigens. Most (217) of the blood samples investigated were collected longitudinally, from each of 61 children, between 2011 and 2014 but another 127 were collected from a cross-sectional sample of children in 2014. FINDINGS: Of the samples from the longitudinal cohort, none of the 153 collected between 2011 and 2013 but 78.7% (48/61) of those collected in 2014 were positive for IgG responses to the chikungunya virus antigen. In the cross-sectional sample, such responses were detected in 96 (75.6%) of the children and occurred at similar prevalence across all age groups. In the same sample, responses to malarial antigen were only detected in eight children (6.3%) but the prevalence of IgG responses to dengue virus antigens was 60.6% (77/127) overall and increased steadily with age. Spatial analysis indicated that the prevalence of IgG responses to the chikungunya virus and one of the dengue virus-like particles decreased as the sampling site moved away from the city of Léogâne and towards the ocean. CONCLUSION: Serological evidence indicates that there had been a rapid and intense dissemination of chikungunya virus in Haiti. The multiplex bead assay appears to be an appropriate serological platform to monitor the seroprevalence of multiple pathogens simultaneously.

West Nile virus ecology in a tropical ecosystem in Guatemala.

West Nile virus ecology has yet to be rigorously investigated in the Caribbean Basin. We identified a transmission focus in Puerto Barrios, Guatemala, and established systematic monitoring of avian abundance and infection, seroconversions in domestic poultry, and viral infections in mosquitoes. West Nile virus transmission was detected annually between May and October from 2005 to 2008. High temperature and low rainfall enhanced the probability of chicken seroconversions, which occurred in both urban and rural sites. West Nile virus was isolated from Culex quinquefasciatus and to a lesser extent, from Culex mollis/Culex inflictus, but not from the most abundant Culex mosquito, Culex nigripalpus. A calculation that combined avian abundance, seroprevalence, and vertebrate reservoir competence suggested that great-tailed grackle (Quiscalus mexicanus) is the major amplifying host in this ecosystem. West Nile virus transmission reached moderate levels in sentinel chickens during 2007, but less than that observed during outbreaks of human disease attributed to West Nile virus in the United States.

Detection of West Nile viral RNA from field-collected mosquitoes in tropical regions by conventional and real-time RT-PCR.

West Nile virus (WNV) is an emerging mosquito-borne flavivirus, which has rapidly spread and is currently widely distributed. Therefore, efforts for WNV early detection and ecological surveillance of this disease agent have been increased around the world. Although virus isolation is known to be the standard method for detection and identification of viruses, the use of RT-PCR assays as routine laboratory tests provides a rapid alterative suitable for the detection of viral RNA on field-collected samples. A method for WNV RNA genome detection in field-collected mosquitoes is presented in this chapter. This method has been designed for virus surveillance in tropical regions endemic for other flaviviruses. Reverse Transcriptase-PCR (RT-PCR) assays, both standard and real time, to detect WNV and other flaviviruses are described. A first screening for flavivirus RNA detection is performed using a conventional RT-PCR with two different sets of flavivirus consensus primers. Mosquito samples are then tested for WNV RNA by a real-time (TaqMan) RT-PCR assay. Sample preparation and RNA extraction procedures are also described.

Construction of yellow fever/St. Louis encephalitis chimeric virus and the use of chimeras as a diagnostic tool.

St. Louis encephalitis (SLE) and West Nile (WN) flaviviruses are genetically closely related and cocirculate in the United States. Virus neutralization tests provide the most specific means for serodiagnosis of infections with these viruses. However, use of wild-type SLE and WN viral strains for laboratory testing is constrained by the biocontainment requirements. We constructed two highly attenuated yellow fever (YF) virus chimeras that contain the premembrane-envelope (prM-E) protein genes from the virulent MSI-7 (isolated in the United States) or the naturally attenuated CorAn9124 (Argentina) SLE strains. The YF/SLE (CorAn version) virus and the previously constructed YF/WN chimera were shown to specifically distinguish between confirmed human SLE and WN cases in a virus neutralization test using patient sera. These chimeras have the potential for use as diagnostic reagents and vaccines against SLE and WN.

Vector competence of Brazilian Aedes aegypti and Ae. albopictus for a Brazilian yellow fever virus isolate.

Because the potential urban yellow fever (YF) mosquito vectors Aedes aegypti and Ae. albopictus are at historical highs in Brazil, both in terms of density and geographical range, we assessed the risk of an urban YF epidemic in Brazil. We evaluated and confirmed in a laboratory setting the vector competence of Brazilian Ae. aegypti for a currently circulating strain of YF virus, and investigated the potential for Brazilian Ae. albopictus to transmit YF.

Evaluation of oral erythromycin and local isoniazid instillation therapy in infants with Bacillus Calmette-Guerin lymphadenitis and abscesses

A randomized placebo-controlled prospective trial was conducted to evaluate the efficacy of erythromycin therapy in 69 patients affected with Bacillus Calmette-Guerin lymphadenitis. When patients who developed subsequent regional abscesses were excluded, erythromycin caused significantly earlier resolution of lymphadenitis (5.1 months vs. 5.7 months for placebo; p < 0.001) compared with placebo. There was no significant difference in the proportion of patients who developed subsequent regional abscesses between the 2 groups (47 percent for erythromycin, 60 percent for placebo, p = 0.14). When the entire group of 69 patients was evaluated for "duration to heal" (regardless of subsequent abscess formation), erythromycin therapy (4.1 +/- 1.5 sd months) did not differ significantly from the placebo group (3.5 +/- 1.3 months, p = not significant). Patients who develop subsequent abscess (n = 36) along with those with B. Calmette-Guerin regional abcesses at presentation (n = 27) were further studied to compare oral erythromycin therapy with that of single dose 50-mg intranodal isoniazid instillation. Local isoniazid therapy caused significantly earlier resolution of the abscesses (3.9 months) compared with erthromycin therapy (5.2 months; p < 0.001). (AU)

Outbreak of Bacillus Calmette-Guerlin-associated lymphadenitis and abscesses in Jamaican children

An outbreak of axillary lymphadenitis and abscesses after Bacillus Calmette-Guerlin (BCG) vaccination (Pasteur Paris, Batch N5122) occurred in 139 Jamaican children between January and July, 1988. The overall rate of this complication was 0.95 percent. The attack rate was 1.92 percent among the 0- to 6 week age group and 0.6 percent in the 7- to 52-week age group. Of 139 patients there were 77 males and 62 females and the mean age at presentation was 4 months. The mean size of the BCG scar, duration of healing and Mantoux reaction size differed significantly in patients compared with those of control infants (P less than 0.01). Mycobacterium bovis was isolated from 11 patients. Immunologically index patients and controls differed significantly only with respect to T lymphocyte subpopulation percentages and concanavalin A stimulation indices. Evaluation of the BCG vaccine did not reveal either increased potency or microbial contamination. We conclude that increased susceptibility to the Pasteur strain of BCG might have contributed to the increased incidence of complications in these Jamaican children and hence caution should be exercised in switching one vaccine for another as is often done in the developing countries. (AU)

Evaluation of oral erythromycin and local instillation of INH therapy, in infants with BCG lymphadenitis - abstract

The most common adverse effect of BCG vaccination is regional lymphadenitis, but the treatment of this complication is controversial. A group of 69 patients, with BCG adenitis following vaccination were randomly assigned to receive either "no therapy" or oral erythromycin for one month. Systemic erythromycin therapy caused earlier resolution of the lymph node but failed to prevent progression to abscess formation. Patients who developed subsequent abscesses (36) and another group who had abscess at the time of presentation (27) showed more rapid resolution when treated with single instillation of isoniazid (50mg) into the abscess cavity, compared to oral erythromycin therapy (AU)

Subacute sclerosing panencephalitis in Jamaica

The clinical features, outcome, electroencephalographic (EEG) and laboratory findings in 12 children with subacute sclerosing panencephalitis are described. The diagnosis was made on the clinical features, the characteristic EEG pattern and the detection of measles complement-fization antibodies in the spinal fluid and serum. The autopsy findings in 2 of 6 patients who died were typical of subacute sclerosing panenecephalitis. This report suggests that the incidence of the condition is high in Jamaica. It is recommended that strenuous efforts be made to improve the measles immunisation status of children and that a registry for the disease be established in the island (AU)

Oral rehydration using high and low sodium and potassium solutions in dehydrated Jamaican children with diarrhoea - abstract

The indications and pathophysiological principles underlying the use of glucose electrolyte solutions for treating diarrhoea with dehydration are well understood. The exact composition for the Caribbean is disputed, because the WHO recommended solution which contains 90mmols/L of sodium was developed for cholera and may produce hypernatremia. To establish the value of this solution in Jamaican children, we studied 84 cases of diarrhoea in children aged 5 to 18 months attending Bustamante Children's Hospital, Kingston. The children were assessed clinically and body weight, blood samples, urine and stool samples were studied at 0, 6 and 24 hours. Treatment was with oral rehydration solution given at a rate of 200 mls per hour. Cases were divided at random into two groups, one given a solution containing 90 mmols Na, the other, 60 mmols of Na. In both groups, clinical and biochemical indices improved rapidly, weight increased, serum specific gravity fell and bicarbonates rose. In the high sodium group, 5 cases developed hypernatremia at 6 hours and persistence of hyponatremia was seen in a few cases in the low sodium group. In a second study, 25 children were given standard GE solution, but the potassium was increased from 20 to 35 mmols/1 and the cases divided randomly into high and normal potassium groups. The GEsol was given as 2 volumes of solution to 1 of water. In this study the high potassium group showed no cases of hypokalemia whereas 19 - 33 percent of the low potassium group had this problem at 24 hours. It was concluded that the standard oral rehydration fluid containing 90 mmols/1 of sodium, given as 2 volumes of water to 1 of water is safe and effective in the cases seen in Jamaica and that a higher potassium concentration of 35mmols/1 would be more effective in correcting hypokalaemia than the present 20 mmol/1 solution. This regime is now standard practise in both Bustamante Children's Hospital and at the University Hospital of the West Indies and has led to dramatic reductions in hospitalization rates, use of drip sets and of intravenous therapy (AU)

Reye's syndrome - a case report

A single case fulfilling the clinical and pathological criteria of Reye's syndrome is reported. The possible aetiology of the syndrome, the diferential diagnosis with special reference to toxic hypoglycaemia induced by ackee and renta yams, and the treatment of the disease are discussed. This report represents to our knowledge the first case of Reye's syndrome thus documented in Jamaica (AU)