Revisión sistemática de la exactitud diagnóstica de la gota gruesa en comparación con la reacción en cadena de la polimerasa para malaria asociada al embarazo, 2010-2022 / Systematic review of the diagnostic accuracy of thick smear compared to polymerase chain reaction for pregnancy-associated malaria, 2010-2022

RESUMEN Objetivos. Evaluar la exactitud de gota gruesa (GG) frente a la reacción en cadena de la polimerasa (PCR) cuantitativa para la malaria asociada al embarazo (MAE). Materiales y métodos. Se realizó una revisión sistemática de pruebas diagnósticas en nueve bases de datos. Se evaluó la calidad metodológica con QUADAS. Se estimó sensibilidad, especificidad, cociente de probabilidad positivo (CPP) y negativo (CPN), razón de odds diagnóstica (ORD) y área bajo la curva ROC. Se determinó la heterogeneidad con el estadístico Q de Der Simonian-Laird y la incertidumbre con el porcentaje de peso de cada estudio sobre el resultado global. Resultados. Se incluyeron diez estudios con 5691 gestantes, 1415 placentas y 84 neonatos. En los estudios con nPCR (PCR anidada) y qPCR (PCR cuantitativa) como estándar, los resultados de exactitud diagnóstica fueron estadísticamente similares, con sensibilidad muy baja (50 y 54%, respectivamente), alta especificidad (99% en ambos casos), alto CPP y deficiente CPN. Usando nPCR la OR diagnóstica fue 162 (IC95%=66-401) y el área bajo la curva ROC fue 95%, mientras que con qPCR fueron 231 (IC95%=27-1951) y 78%, respectivamente. Conclusiones. Mediante un protocolo exhaustivo se demostró el bajo desarrollo de investigaciones sobre la exactitud diagnóstica de la GG en MAE. Se demostró que la microscopía tiene un desempeño deficiente para el diagnóstico de infecciones asintomáticas o de baja parasitemia, lo que afianza la importancia de implementar otro tipo de técnicas en el seguimiento y control de las infecciones por malaria en las gestantes, con el fin de lograr el control y posible eliminación de la MAE.

ABSTRACT Objective. To evaluate the accuracy of thick smear (TS) versus quantitative polymerase chain reaction (PCR) for pregnancy-associated malaria (PAM). Materials and methods. We carried out a systematic review of diagnostic tests in nine databases. Methodological quality was evaluated with QUADAS. Sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and area under the ROC curve were estimated. Heterogeneity was determined with the Der Simonian-Laird Q method and uncertainty with the weighted percentage of each study on the overall result. Results. We included 10 studies with 5691 pregnant women, 1415 placentas and 84 neonates. In the studies with nested PCR (nPCR) and quantitative PCR (qPCR) as the standard, the diagnostic accuracy results were statistically similar, with very low sensitivity (50 and 54%, respectively), high specificity (99% in both cases), high PLR and poor NLR. When nPCR was used, the DOR was 162 (95%CI=66-401) and the area under the ROC curve was 95%, while with qPCR it was 231 (95%CI=27-1951) and 78%, respectively. Conclusions. We demonstrated that research on the diagnostic accuracy of TS in PAM is limited. Microscopy showed poor performance in the diagnosis of asymptomatic or low parasitemia infections, which reinforces the importance of implementing other types of techniques for the follow-up and control of malaria infections in pregnant women, in order to achieve the control and possible elimination of PAM.

Prevalence of asymptomatic Plasmodium vivax infections in the north-eastern focus of malaria of Venezuela / Prevalencia de infecciones asintomáticas por Plasmodium vivax en el foco malárico oriental de Venezuela

Malaria remains as a public health problem in Venezuela. In 2015 there were 136,402 cases reported by the Ministry of Popular Power for Health, being the parasite prevalence 73.95% for Plasmodium vivax, 17.6% for Plasmodium falciparum, 0.0095% for Plasmodium malariae and 8.42% mixed infections (P. vivax + P. falciparum). During the period 1999-2002 the number of cases in Venezuela ranged between 21,685 and 29,337, being the Sucre State with highest levels of malaria prevalence, with Plasmodium vivax as the unique specie in this region. In 2002 the Municipality of Cajigal had the highest Annual Parasite Incidence (API) of country, being 260 cases per 1000 inhabitants. In view of the difficulty in controlling malaria in this area, the prevalence of asymptomatic carriers was investigated as one of the epidemiological factors contributing to the persistence of malaria transmission. One hundred fifty people were included in the study, with no history of recent malaria infection, or any symptom and also, not having used antimalarial drugs during the 30 days prior to study entry. To do this, a malaria Rapid Diagnostic Test (mRDTs) was used for the determination of antigenemic (OptiMAL®) and PCR (polymerase chain reaction) in conjunction with the reference "Gold Standard", the conventional thick and thin blood smears (TTBS). It was found a prevalence of infection of 1.33% by mRDTs and TTBS and 8% by PCR which allowed the detection of 10 asymptomatic cases in addition, with a sensitivity and specificity of 100% and 93.4% respectively. The presence of asymptomatic carriers in this area reveals the difficulties that face the Malaria Control Program in the eventual elimination of this specific malaria foci. It is necessary reinforces the maintenance of the epidemiological surveillance using more sensitive diagnostic techniques, as well as to adapt the control measures based on the current findings.

La malaria sigue siendo un problema de salud pública en Venezuela. Para el año 2015 el Ministerio del Poder Popular para la Salud reportó 136.402 casos, siendo la fórmula parasitaria 73,95% para Plasmodium vivax, 17,6% para Plasmodium falciparum, 0,0095 para Plasmodium malariae y 8,42% para infecciones mixtas (P. vivax + P. falciparum). Durante el período 1999-2002, el número de casos en Venezuela estuvo entre 21.685 y 29.337, siendo el Estado Sucre el que mostró los niveles más altos de prevalencia de malaria, con P. vivax como única especie en la región. En el año 2002 el Municipio Cajigal registró el Índice Parasitario Anual (IPA) más alto del país, siendo 260 casos por 1000 habitantes. En vista de las dificultades para controlar la malaria en esta área, se investigó la prevalencia de portadores asintomáticos como uno de los factores contribuyentes en la persistencia de la transmisión malárica. Ciento cincuenta personas fueron incluidas en el estudio sin historia de infección reciente por malaria o ningún síntoma, así como no haber consumido drogas antimaláricas durante los 30 días anteriores de ingresar al estudio. Para ello, se usó la prueba rápida de diagnóstico para malaria (PRDxm) para la determinación de antígenemia (OptiMAL®) y la técnica de biología molecular basada en la Reacción en Cadena de la Polimerasa (PCR), conjuntamente con la "prueba oro," como método convencional, la Gota Gruesa y Extendido de Sangre (GGES). Se encontró una prevalencia de infección de 1,33% por GGES y por prueba rápida de diagnóstico OptiMAL® y 8% mediante PCR. La técnica de PCR permitió la detección adicional de 10 casos asintomáticos con una sensibilidad y especificidad del 100% y 93,4% respectivamente. La presencia de portadores asintomáticos en esta área revela las dificultades que enfrenta el Programa de Control de la Malaria en la eliminación eventual de esta parasitosis en este foco. Es necesario reforzar el mantenimiento de la vigilancia epidemiológica usando técnicas de diagnóstico más sensibles, así como adoptar medidas de control basadas en estos hallazgos.

Performance Evaluation of the CellaVisionTM DM9 6 Analyzer During Detection of Intracellular Parasites of Peripheral Blood Smears / 现代检验医学杂志

Objective To evaluate the performance of the CellaVisionTM DM96 analyzer during detection of intracellular para-sites of peripheral blood smears.Methods This study compared the detection rates of Plasmodium and Babesia species on peripheral blood smears utilizing the CellaVision DM9 6 with the rates for a routine red blood cell morphology scan.A total of 307 slides were analyzed,consisting of 142 slides positive for Plasmodium or Babesia species and 165 negative controls. Slides were blinded,randomized,and analyzed by CellaVision 9 6 and microscopy for red cell morphology scans.The technolo-gists were blinded to prior identification.Results The examination of common technician and blood professional technician, whether using optical microscope or CellaVision DM9 6 could accurately identify all the negative control,its specificity was 100%.The sensitivity of blood professionals using CellaVision DM96 was not statistically significant in the sensitivity of the laboratory and the use of light microscopy for the detection of Plasmodium parasites (χ2=0.24,0.03,0.43,P>0.05).The higher percentage of Plasmodium in blood smear,the higher detection rate of CellaVision DM9 6 .When the blood smear Plas-modium white rate greater than 1%,only 2 contain Plasmodium falciparum samples were negative for the miscarriage of j us-tice.The blood smear percentage was higher than 2% CellaVision of Plasmodium DM96 will all the blood smear 100% cor-rect interpretation.Conclusion This study demonstrates that CellaVision had the potential to detect intracellular parasites in routine screening of blood smears resource for storing images to be used for educational purposes,including training technol-ogists in the detection of intracellular parasites.

Canine heartworm disease in Porto Velho: first record, distribution map and occurrence of positive mosquitoes / Dirofilariose canina em Porto Velho: primeiro registro, mapa de distribuicao e ocorrencia de mosquitos positivos

The aim of this study was to make the first report on canine heartworm disease in the state of Rondônia and confirm its transmission in this state. Blood samples were randomly collected from 727 dogs in the city of Porto Velho. The samples were analyzed to search for microfilariae and circulating antigens, using three different techniques: optical microscopy on thick blood smears stained with Giemsa; immunochromatography; and PCR. Mosquitoes were collected inside and outside the homes of all the cases of positive dogs and were tested using PCR to search for DNA of Dirofilaria immitis. Ninety-three blood samples out of 727 (12.8%) were positive according to the immunoassay technique and none according to the thick smear method. Among the 93 positive dogs, 89 (95.7%) were born in Porto Velho. No difference in the frequency of infection was observed between dogs raised indoors and in the yard. PCR on the mosquitoes resulted in only one positive pool. This result shows that the transmission of canine heartworm disease is occurring in the city of Porto Velho and that there is moderate prevalence among the dogs. The techniques of immunochromatography and PCR were more effective for detecting canine heartworm than thick blood smears. The confirmation of canine heartworm disease transmission in Porto Velho places this disease in the ranking for differential diagnosis of pulmonary nodules in humans in Rondônia.

O objetivo deste estudo foi de registrar pela primeira vez a dirofilariose canina no estado de Rondônia e confirmar sua transmissão neste estado. Amostras de sangue de 727 cães foram colhidas aleatoriamente na cidade de Porto Velho. As amostras foram analisadas em busca de microfilárias e antígenos circulantes usando três técnicas diferentes: microscopia ótica de gota espessa corada com Giemsa e imunocromatografia de fluxo lateral e PCR. Mosquitos foram colhidos no domicilio e peridomicílio de todos os casos de cães positivos, estes mosquitos foram testados pela PCR na detecção de DNA de Dirofilaria immitis. Noventa e três das 727 amostras de sangue foram positivas na técnica de imunoensaio (12,8%). Nenhuma amostra foi positiva na gota espessa. Entre os 93 cães positivos, 89 (95,7%) foram nascidos em Porto Velho. Nenhuma diferença na frequencia de infecção foi observada entre cães criados dentro da casa ou no quintal. O PCR dos mosquitos resultou em apenas um pool positivo. Este resultado mostra que a transmissão de dirofilariose canina está ocorrendo na cidade de Porto Velho e a frequência que ocorre nos cães é considerada moderada. As técnicas de imunocromatografia e PCR são mais eficazes na detecção de dirofilariose comparadas a gota espessa. A confirmação de transmissão de dirofilariose canina em Porto Velho, coloca esta doença no ranking de diagnóstico diferencial de nódulos pulmonares em seres humanos em Rondônia.

Babesia spp. infection in dogs from rural areas of São Paulo State, Brazil / Infecção por Babesia spp. em cães de áreas rurais do estado de São Paulo, Brasil

The status of Babesia spp. infection in dogs from rural areas of São Paulo State, Brazil was studied. For this, 150 animals were examined by blood smears and by PCR; the presence of tick infestation was also investigated. By the blood smear examination, 3 animals (2 percent) were detected positive and by PCR for Babesia spp. 12 (8 percent) were positive, with bands visualized in 450 bp. Rhipicephalus sanguineus or Amblyomma spp. were found on 36 (24 percent) of the 150 dogs. Amblyomma species found were A. cajennense (9/36-25 percent) and A. ovale (9/36-25 percent). It was not possible to correlate the presence of R. sanguineus and the infection with Babesia spp. The sequencing of four positive samples demonstrated close identity with B. canis vogeli already characterized in Brazil.

A presença de infecção por Babesia spp. em cães de áreas rurais do Estado de São Paulo, Brasil foi investigada. Para tanto, 150 cães foram examinados por técnicas parasitológicas de esfregaços sanguíneos e moleculares (PCR), e também, foi verificada a presença de carrapatos nestes animais. Pela análise de esfregaços sanguíneos, 3 (2 por cento) dos cães estavam infectados, enquanto pela PCR, 12 (8 por cento) dos animais foram positivos com bandas aproximadas de 450 pares de base (pb). Foram observados 36 (24 por cento) cães infestados com Rhipicephalus sanguineus ou com Amblyomma spp. As espécies de Amblyomma observadas foram A. cajennense (25 por cento) e A. ovale (25 por cento). Não foi possível correlacionar a presença de R. sanguineus com a infecção por Babesia spp. O seqüenciamento de quatro amostras positivas demonstrou alta identidade com B. canis vogeli, já caracterizada no Brasil.

Ocorrência de babesiose canina no Município de Uberlândia, Minas Gerais / Incidence of canine babesiosis in Uberlândia, Minas Gerais

Babesia canis é um protozoário intraeritrocítico transmitido pelo carrapato Rhipicephalus sanguineus que acomete principalmente canídeos domésticos e silvestres, causando manifestações clínicas como anorexia, pirexia, hemoglobinúria, esplenomegalia, hemoglobinemia, anemia grave, podendo o animal recuperar-se lentamente ou morrer. O objetivo desta pesquisa foi determinar a ocorrência da doença em Uberlândia – MG e comparar os métodos de esfregaços sangüíneos de ponta de orelha e Reação de Imunofluorescência Indireta (RIFI) no diagnóstico desta enfermidade. Para realização deste trabalho, foram colhidos aleatoriamente soros de 143 cães atendidos no Hospital Veterinário da Universidade Federal de Uberlândia para exame de RIFI enquanto que 772 esfregaços sangüíneos de ponta de orelha foram feitos e corados pelo Giemsa para a pesquisa do hemoparasito. Após a padronização da RIFI, considerou-se positivo soros com diluição igual ou superior a 1:20 e como negativos soros com diluição inferior a 1:20. Dos soros testados, através da RIFI, 51,74% estavam positivos e 48,26% negativos. Dos esfregaços sangüíneos 2,72% eram positivos para babesiose, 87,83% negativos e 9,45% positivos para outros hemoparasitos. Através do teste Qui-quadrado observou-se diferença significativa, em nível de significância 5%, entre os métodos comparados.

A modified field stain for rapid staining of thick and thin blood smears

A modified Field stain for the rapid and accurate diagnosis of malaria in both thick and thin smears is here described. It is particularly useful in routine laboratory diagnosis and is very economical. Its usefulness may also be taken advantage of in studies of bone marrow, splenic, and brain smears; in other hematological studies; and in staining other haemoprotozoan parasites such as trypanosomes and microfilaria (Conclusion)