First inter-laboratory comparison of Echinococcus granulosus sensu lato diagnosis in Latin America

[ABSTRACT]. Objective. To compare the performance of polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) tests for diagnosing Echinococcus granulosus in dog feces among national reference laboratories in Argentina, Chile, Peru, and Uruguay. Methods. National laboratories affiliated with the Ministry of Health/Agriculture of each country exchanged panels of 10 positive/negative samples obtained from their regular national surveillance programs in November 2015 – November 2016. All laboratories applied PCR; two also applied ELISA techniques. Sensitivity and specificity were determined for each laboratory and concordance of results among the laboratories was evaluated by Cohen Kappa coefficient. Results. Poor concordance (3 of 10 paired comparisons had values of Kappa > 0.4), low sensitivity and specificity across all laboratories, and poor performance of both techniques in detecting E. granulosus in canine feces was demonstrated in this study. An ex-post comparison of the laboratories’ test protocols showed substantial heterogeneity that could partially explain poor concordance of results. Conclusion. The results underscore the heterogeneity of canine echinococcosis diagnosis across the region and indicate possible sources of variability. Efforts to standardize canine echinococcosis testing must be included in the plan of action for the Regional Initiative for the Control of Cystic Echinococcosis. Future comparisons with fecal samples of known parasite load are needed.

[RESUMEN]. Objetivo. Comparar el rendimiento de los ensayos de la reacción en cadena de la polimerasa y el enzimoinmunoanálisis de adsorción en fase sólida (o ELISA, por su sigla en inglés) para diagnosticar Echinococcus granulosus en heces caninas en los laboratorios de referencia nacionales de Argentina, Chile, Perú y Uruguay. Métodos. Los laboratorios nacionales, afiliados a los ministerios de salud y agricultura y ganadería de cada país, intercambiaron paneles de diez muestras positivas y negativas obtenidas de sus respectivos programas nacionales de vigilancia desde el mes de noviembre del año 2015 hasta el mismo mes del año siguiente. Todos los laboratorios emplearon la reacción en cadena de la polimerasa y dos emplearon también técnicas de ensayo inmunoenzimático (ELISA). Se determinó la sensibilidad y la especificidad de cada laboratorio y se evaluó la concordancia entre los resultados de los laboratorios mediante el coeficiente kappa de Cohen. Resultados. Este estudio descubrió una escasa concordancia (3 de 10 comparaciones de pares obtuvieron valores de kappa > 0,4), una sensibilidad y especificidad bajas en todos los laboratorios y un rendimiento deficiente de ambas técnicas de diagnóstico de Echinococcus granulosus en heces caninas. La comparación ex post de los protocolos de ensayo de los laboratorios mostró una heterogeneidad sustancial que podría explicar parcialmente la escasa concordancia de los resultados. Conclusiones. Los resultados subrayan la heterogeneidad del diagnóstico de equinococosis canina en toda la región e indican posibles fuentes de esta variabilidad. Deben incluirse medidas para estandarizar la prueba de equinococosis canina en el plan de acción de la Iniciativa Sudamericana para el Control de la Equinococosis Quística. En el futuro serán necesarias comparaciones adicionales con muestras fecales con una carga de parásitos conocida.

[RESUMO]. Objetivo. Comparar o desempenho dos métodos de reação em cadeia da polimerase (PCR) e ensaio imunoenzimático (ELISA) no diagnóstico de infecção pelo Echinococcus granulosus em fezes de cães entre laboratórios de referência nacional na Argentina, Chile, Peru e Uruguai. Métodos. Laboratórios nacionais conveniados ao Ministério da Saúde/Agricultura de cada país participante intercambiaram grupos de 10 amostras positivas/negativas coletadas rotineiramente pelos programas nacionais de vigilância no período de novembro de 2015 a novembro de 2016. Todos os laboratórios empregaram o método de PCR e dois empregaram também o método de ELISA. A sensibilidade e a especificidade dos métodos foram determinadas em cada laboratório, e a concordância dos resultados entre os laboratórios participantes foi avaliada com o coeficiente kappa de Cohen. Resultados. Observou-se fraca concordância (3 de 10 comparações pareadas com kappa >0,4), baixa sensibilidade e especificidade e fraco desempenho de ambos os métodos na identificação do E. granulosus em amostras fecais de cães nos laboratórios participantes do estudo. Uma comparação retroativa revelou considerável heterogeneidade dos protocolos de análise laboratorial, o que poderia em parte explicar a fraca concordância entre os resultados. Conclusões. Os resultados deste estudo apontam para a falta de uniformidade no diagnóstico de equinococose canina em toda a Região e indicam possíveis causas para variabilidade. A padronização da análise laboratorial da equinococose canina deve constar do plano de ação para a Iniciativa Regional para Controle da Hidatidose. Outras comparações de amostras fecais de parasitas conhecidos devem ser realizadas.

First inter-laboratory comparison of Echinococcus granulosus sensu lato diagnosis in Latin America.

OBJECTIVE: To compare the performance of polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) tests for diagnosing Echinococcus granulosus in dog feces among national reference laboratories in Argentina, Chile, Peru, and Uruguay. METHODS: National laboratories affiliated with the Ministry of Health/Agriculture of each country exchanged panels of 10 positive/negative samples obtained from their regular national surveillance programs in November 2015 - November 2016. All laboratories applied PCR; two also applied ELISA techniques. Sensitivity and specificity were determined for each laboratory and concordance of results among the laboratories was evaluated by Cohen Kappa coefficient. RESULTS: Poor concordance (3 of 10 paired comparisons had values of Kappa > 0.4), low sensitivity and specificity across all laboratories, and poor performance of both techniques in detecting E. granulosus in canine feces was demonstrated in this study. An ex-post comparison of the laboratories' test protocols showed substantial heterogeneity that could partially explain poor concordance of results. CONCLUSION: The results underscore the heterogeneity of canine echinococcosis diagnosis across the region and indicate possible sources of variability. Efforts to standardize canine echinococcosis testing must be included in the plan of action for the Regional Initiative for the Control of Cystic Echinococcosis. Future comparisons with fecal samples of known parasite load are needed.

Building the road to a regional zoonoses strategy: A survey of zoonoses programmes in the Americas.

BACKGROUND: In recent years, global public health security has been threatened by zoonotic disease emergence as exemplified by outbreaks of H5N1 and H1N1 influenza, SARS, and most recently Ebola and Zika. Additionally, endemic zoonoses, such as rabies, burden countries year after year, placing demands on limited finances and personnel. To survey the baseline status of the emerging and endemic zoonoses programmes of the Latin American and the Caribbean (LAC) countries, the Pan American Health Organization (PAHO) conducted a survey of priority emerging and endemic zoonoses, countries´ prioritization criteria and methodologies, and suggestions to strengthen countries capacities and regional approaches to zoonoses control. METHODS: A fillable online questionnaire was sent to the zoonoses programme managers of the Ministries of Health (MOH) and Ministries of Agriculture (MAg) of 33 LAC countries from January to April of 2015. The questionnaire comprised 36 single, multiple choice and open-ended questions to inform the objectives of the survey. A descriptive exploratory analysis was completed. RESULTS: Fifty-four ministries (26 MOH, 25 MAg, and 3 combined responses) in 31 LAC countries responded to the survey. Within the ministries, 22 (85%) MOH, 5 (20%) MAg, and 2 (67%) combined entities indicated they had specialized zoonoses units. For endemic zoonoses, 32 of 54 ministries responded that they conduct formal prioritization exercises, most of them annually (69%). The three priority endemic zoonoses for the MOHs were leptospirosis, rabies, and brucellosis while the three priorities for the MAgs were brucellosis, rabies, and tuberculosis. Diagnosis for rabies and leptospirosis were cited as the capacities most in need of development. The most needed cross-cutting capacity was coordination between stakeholders. For emerging zoonoses, 28 ministries performed formal prioritization exercises. The top prioritization criteria were probability of introduction into the country and impact. The three priority emerging zoonoses for the MOHs were Ebola viral disease, avian influenza, and Chikungunya while for the MAgs were avian influenza, bovine spongiform encephalopathy and West Nile virus disease. Surveillance for avian influenza and Ebola, and diagnosis for BSE were quoted as the capacities most needed. For all zoonoses, the majority of respondents (69%) ranked their relationship with the other Ministry as productive or very productive, and 31% minimally productive. Many countries requested a formal regional network, better regional communication and collaboration, and integrated surveillance. CONCLUSIONS: The survey is the first comprehensive effort to date to inform the status of zoonoses programmes in LAC. The information collected here will be used to develop a regional strategy for zoonoses (both endemic and emerging), increase efforts, advocacy, and promote prompt identification and management of EIDs and improvement of endemic programmes.