First report on surface aspects of Mansonella ozzardi (spirurida: onchocercidae) microfilariae by scanning electron microscopy: preliminary results

Blood samples from Mansonella ozzardi infected volunteers from Vila Antimary (Amazonas State) were processed and a protocol to isolate and prepare microfilariae was carried out in order to perform Scanning Electron Microscopy (SEM) analysis. Data obtained from ultrastructure showed some undescribed structural points of the parasite such as a dimple in the anterior end of the larva and small points ­orifice-like­ that may be related to amphidial structures or simply pores. Another interesting feature was the tip of the tail which is very similar to that found in the rodent parasite Dunnifilaria meningica

Hallazgo incidental de microfilarias de Mansonella ozzardi en un paciente pediátrico con linfoma T anaplásico / Incidental finding of Mansonella ozzardi in a paediatric patient with anaplastic lymphoma

Resumen Las filariasis son parasitosis producidas por nemátodos hemáticos de la familia Filariidae, la Mansonella ozzardi, es uno de los agentes etiológicos distribuido ampliamente en el continente americano y en el Caribe. Presentamos el caso de una paciente de 13 años de edad, previamente diagnosticada con linfoma T de célula grande anaplásico. Como parte de la evaluación antes del segundo ciclo B de quimioterapia, se realizó un extendido de sangre periférica en el que se encontró una microfilaría tipificada como Mansonella ozzardi, se dio manejo con una dosis única de ivermectina y se logró resultado negativo en el control a las 24 horas. Actualmente la paciente se encuentra asintomática y sin evidencia de recurrencia de la parasitemia y terminando su tratamiento oncológico.

Abstract Filariasis is caused by nematodes in the blood. Mansonella ozzardi is one of the aetiological agents widely distributed in the Americas and the Caribbean. The case is presented on a paediatric patient previously diagnosed with T-cell anaplastic large cell lymphoma. As part of the evaluation before the second cycle B chemotherapy, a peripheral blood smear was performed, in which were found microfilaria, identified as Mansonella ozzardi. The treatment was a single dose of ivermectin, with a negative result being obtained at 24 hours. The patient is currently asymptomatic and with no evidence of recurrence of the parasitaemia, and able to finish the cancer treatment.

Sensitivity of diagnostic methods for Mansonella ozzardi microfilariae detection in the Brazilian Amazon Region

BACKGROUND The human filarial worm Mansonella ozzardi is highly endemic in the large tributaries of the Amazon River. This infection is still highly neglected and can be falsely negative when microfilariae levels are low. OBJECTIVES This study investigated the frequency of individuals with M. ozzardi in riverine communities in Coari municipality, Brazilian Amazon. METHODS Different diagnostic methods including polymerase chain reaction (PCR), blood polycarbonate membrane filtration (PCMF), Knott's method (Knott), digital thick blood smears (DTBS) and venous thick blood smears (VTBS) were used to compare sensitivity and specificity among the methods. Data were analysed using PCMF and Bayesian latent class models (BLCM) as the gold standard. We used BLCM to calculate the prevalence of mansonelliasis based on the results of five diagnostic methods. FINDINGS The prevalence of mansonelliasis was 35.4% by PCMF and 30.1% by BLCM. PCR and Knott methods both possessed high sensitivity. Sensitivity relative to PCMF was 98.5% [95% confidence interval (CI): 92.0 - 99.7] for PCR and 83.5% (95% CI: 72.9 - 90.5) for Knott. Sensitivity derived by BLCM was 100% (95% CI 93.7 - 100) for PCMF, 100% (95% CI: 93.7 - 100) for PCR and 98.3% (95% CI: 90.6 - 99.9) for Knott. The odds ratio of being diagnosed as microfilaremic increased with age but did not differ between genders. Microfilariae loads were higher in subjects aged 30 - 45 and 45 - 60 years. MAIN CONCLUSIONS PCMF and PCR were the best methods to assess the prevalence of mansonelliasis in our samples. As such, using these methods could lead to higher prevalence of mansonelliasis in this region than the most commonly used method (i.e., thick blood smears).

Historic accounts of Mansonella parasitaemias in the South Pacific and their relevance to lymphatic filariasis elimination efforts today

There are two species of filarial parasites with sheathless microfilariae known to commonly cause parasitaemias in humans: Mansonella perstans and Mansonella ozzardi. In most contemporary accounts of the distribution of these parasites, neither is usually considered to occur anywhere in the Eastern Hemisphere. However, Sir Patrick Manson, who first described both parasite species, recorded the existence of sheathless sharp-tailed Mansonella ozzardi-like parasites occurring in the blood of natives from New Guinea in each and every version of his manual for tropical disease that he wrote before his death in 1922. Manson's reports were based on his own identifications and were made from at least two independent blood sample collections that were taken from the island. Pacific region Mansonella perstans parasitaemias were also later (in 1923) reported to occur in New Guinea and once before this (in 1905) in Fiji. Although Mansonella-parasitaemias are generally regarded as benign, they are thought to be of public health importance because they can affect the epidemiological monitoring of other filarial diseases. In this article, we reviewed the historic literature concerning Pacific-origin Mansonella-parasitaemias in an attempt to explain how, despite repeated reports of Pacific-region Mansonella-parasitaemias, by as early as the 1970s, the WHO had arrived at the present-day view that Wuchereria bancrofti is the only cause of filarial parasitaemias in Papua New Guinea. We have also evaluated the evidence supporting the contemporary existence of Pacific-area parasitaemia-causing Mansonella parasites and assessed the relevance such parasites could have for present-day lymphatic filariasis elimination efforts in the region.

Historic accounts of Mansonella parasitaemias in the South Pacific and their relevance to lymphatic filariasis elimination efforts today

There are two species of filarial parasites with sheathless microfilariae known to commonly cause parasitaemias in humans: Mansonella perstans and Mansonella ozzardi. In most contemporary accounts of the distribution of these parasites, neither is usually considered to occur anywhere in the Eastern Hemisphere. However, Sir Patrick Manson, who first described both parasite species, recorded the existence of sheathless sharp-tailed Mansonella ozzardi-like parasites occurring in the blood of natives from New Guinea in each and every version of his manual for tropical disease that he wrote before his death in 1922. Manson's reports were based on his own identifications and were made from at least two independent blood sample collections that were taken from the island. Pacific region Mansonella perstans parasitaemias were also later (in 1923) reported to occur in New Guinea and once before this (in 1905) in Fiji. Although Mansonella-parasitaemias are generally regarded as benign, they are thought to be of public health importance because they can affect the epidemiological monitoring of other filarial diseases. In this article, we reviewed the historic literature concerning Pacific-origin Mansonella-parasitaemias in an attempt to explain how, despite repeated reports of Pacific-region Mansonella-parasitaemias, by as early as the 1970s, the WHO had arrived at the present-day view that Wuchereria bancrofti is the only cause of filarial parasitaemias in Papua New Guinea. We have also evaluated the evidence supporting the contemporary existence of Pacific-area parasitaemia-causing Mansonella parasites and assessed the relevance such parasites could have for present-day lymphatic filariasis elimination efforts in the region.

Prevalencia y factores asociados con la filariosis por Mansonella ozzardi en 2 comunidades periurbanas de Iquitos, 2009 / Prevalence of filariasis by Mansonella ozzardi and associated factors among 2 suburban communities of Iquitos, 2009

Introducción: Tres casos de infección por Mansonella ozzardi (M. ozzardi) en muestras de malaria que provenían de 2 comunidades periurbanas de Iquitos (Perú) dieron la sospecha de transmisión local. El objetivo del estudio fue determinar la prevalencia y factores asociados con la filariosis por M. ozzardi en estas comunidades. Materiales y métodos: Se realizó un estudio transversal en las comunidades de Laguna Azul y La Unión en Iquitos. A todos los pobladores se les tomó una gota gruesa para la detección de M. ozzardi y se les realizó una encuesta epidemiológica. Se realizó colecta de larvas y mosquitos para identificación de potenciales vectores. Se calcularon los OR ajustados (ORa) usando regresión logística múltiple. Resultados: Se evaluaron a 433 personas; 58% fueron mujeres; la mediana de edad fue de 20 años; 58,2% fueron migrantes, 3,7% pescadores y 12,9% habían viajado por las cuencas del Alto anay. La prevalencia de M. ozzardi fue de 1,4% (6/433) y el más joven de los casos tuvo 31 años; se encontró asociación con ser pescador (ORa: 8,7; IC 95: 1,1-76,0) y con haber realizado viajes por la cuenca del Alto Nanay (ORa: 11,2; IC 95: 1,2-112,5). No se evidenció densidad significativa de vectores simúlidos o culicoides. Conclusión: Las comunidades estudiadas tuvieron una baja prevalencia de M. ozzardi y por la edad de los casos y los factores asociados encontrados se sospecha infección foránea a la zona de estudio, en especial en la cuenca del Alto Nanay.

Introduction: Three cases of M. ozzardi infection from 2 suburban communities in Iquitos, Peru, led to a suspicion of local transmission. The objective of the study was to determine the prevalence of filariasis by M. ozzardi and its associated factors among these communities. Materials and methods: A cross-sectional study was performed, as well as an epidemiological survey and a thick smear blood test. Larvae and mosquitoes were collected. The adjusted OR (aOR) using multiple logistic regression was calculated. Results: A total of 433 participants were enrolled; 58% were women. The prevalence of M. ozzardi was 1.4% and the associated factors included being a fisherman (aOR: 8.7; 95%CI: 1.1-76.0) and being on the Alto Nanay river (aOR: 11.2; 95%CI: 1.2-112.5). No significant evidence of simulidos or culicoides was found. Conclusion: The low prevalence of M. ozzardi found suggests a foreign infection, probably derived from the Alto Nanay river.

Mansonelosis por Mansonella ozzardi en voluntarios para despistaje de malaria en la Amazon¡a peruana / Mansonelosis by Mansonella ozzardi in volunteers undergoing screening for malaria in the peruvian Amazon

Objetivos. Determinar la frecuencia, manifestaciones cl¡nicas y factores asociados a la infecci¢n por Mansonella ozzardi en voluntarios de una campa¤a de despistaje de malaria en el distrito de Alto Nanay en la selva amaz¢nica del Per£. Materiales y m‚todos. Se realiz¢ un estudio descriptivo, anal¡tico y transversal. Los participantes fueron entrevistados y examinados por un m‚dico y los datos fueron registrados en una ficha cl¡nica. El diagn¢stico de infecci¢n por M. ozzardi se realiz¢ mediante la t‚cnica de gota gruesa y frotis. Resultados. La frecuencia de mansonelosis en esta poblaci¢n fue 47,8% (IC 95%: 39,1–56,6). Mediante el an lisis bivariado se encontr¢ que el reporte de disminuci¢n de la agudeza visual o visi¢n borrosa y la presencia de tumoraciones subcut neas fueron los signos y s¡ntomas estad¡sticamente asociados con la infecci¢n por microfilarias (p<0,05). La regresi¢n log¡stica encontr¢ asociaci¢n estad¡stica para la residencia en localidades del r¡o Pintuyacu o Alto Nanay, la ocupaci¢n en lugares alejados del centro poblado, la presencia de tumores subcut neos y el engrosamiento de la piel (p<0,05).Conclusiones . Existe una elevada frecuencia de mansonelosis por M. ozzardi en el distrito de Alto Nanay, la cual se encontr¢ significativamente relacionada con ocupaciones realizadas fuera del centro poblado, residencia en localidades del r¡o Pintuyacu y lesiones cut neas.

Objectives. To determine the frequency, clinical features, and factors associated with M. ozzardi infection in volunteers of a malaria screening campaign in the district of Alto Nanay in the Amazon jungle of Peru. Materials and methods. A descriptive, analytical and cross-sectional study was performed. The participants were interviewed and examined by a physician and the data were recorded in a medical record. The diagnosis of M. ozzardi infection was performed using the method of thick blood smear and film. Results.The frequency of mansonelosis in this population was 47.8% (95% CI: 39.1 to 56.6). Through bivariate analysis we found that the report of decreased visual acuity or blurred vision and presence of subcutaneous tumors were the signs and symptoms statistically associated with the infection of microfilariae (p<0.05). Logistic regression found statistical association for residency in localities of the Pintuyacu or Alto Nanay rivers, employment in places far from the town center, the presence of subcutaneous tumors and skin thickening (p<0.05). Conclusions. There was a high number of mansonelosis by M. ozzardi in the district of Alto Nanay which was significantly related to working outside the town center, residing in the area of the Pintuyacu River, and skin lesions.

Mansonelliasis, a neglected parasitic disease in Haiti

Reported in Haiti as early as 1923, Mansonella ozzardi is still a neglected disease ignored by the health authorities of the country. This review is an update on the geographic distribution of the coastal foci of mansonelliasis in Haiti, the epidemiological profile and prevalence rates of microfilariae in people living in endemic areas, the clinical impact of the parasite on health and the efficiency of the transmission of the parasite among three Culicoides biting-midge species identified as vectors in Haiti. Additionally, interest in establishing a treatment programme to combat this parasite using a single dose of ivermectin is emphasised.

Outstanding insecurities concerning the use of an Ov16-based ELISA in the Amazonia onchocerciasis focus

In a recent issue of Memórias do Instituto Oswaldo Cruz, published in Rio de Janeiro in February 2014 (109: 87-92), Adami et al. have published a survey reporting Mansonella parasite prevalence in the Amazon Region. This report makes a useful contribution to the existing knowledge of filarial parasite distribution within the Amazon area, parasite prevalence rates in relation to age and occupation and provides observations on the possible clinical impact of Mansonella ozzardi. Their publication also provides an account of what appears to be a novel ELISA that has recently been used in the Simuliidae and Onchocerciasis Laboratory of the Oswaldo Cruz Institute, Rio de Janeiro, Brazil. We are concerned that the publication of this ELISA may have created an excessively positive impression of the effectiveness of the onchocerciasis recrudescence serological surveillance tools that are presently available for use in the Amazonia onchocerciasis focus. In this letter we have, thus, sought to highlight some of the limitations of this ELISA and suggest how continuing insecurities concerning the detection of antibodies to Onchocerca volvulus within the Amazonia onchocerciasis focus might be minimised.

Mansonella ozzardi in the municipality of Tefé, Amazonas, Brazil, 60 years after the first report: an epidemiologic study

The prevalence of mansonelliasis was studied in the municipality of Tefé, state of Amazonas, Brazil. The prevalence (thick blood smear method) was 13.6% (147/1,078), higher in the Solimões River region (16.3%) than in the Tefé River region (6.3%). In the sampled communities in the Solimões River region, a higher density of cases was observed, as indicated by a kernel analysis (odds ratio 0.34; 95% confidence interval: 0.20-0.57). Males had a higher prevalence (χ2 = 31.292, p < 0.001) than women. Mansonella ozzardi prevalence was higher in retirees and farmers (28.9% and 27%, respectively). Prevalence also significantly increased with age (χ2 = -128.17, p < 0.001), with the highest numbers occurring in persons older than 67 years.

New records of Mansonella ozzardi: a parasite that is spreading from the state of Amazonas to previously uninfected areas of the state of Acre in the Purus River region

Mansonella ozzardi infections are common in the riverside communities along the Solimões, Negro and Purus Rivers in the state of Amazonas (AM). However, little is known about the presence of this parasite in communities located in regions bordering AM and the state of Acre. The prevalence rate of M. ozzardi infections was determined in blood samples from volunteers according to the Knott method. A total of 355 volunteers from six riverine communities were enrolled in the study and 65 (18.3%) were found to be infected with M. ozzardi. As expected, most of the infections (25%) occurred in individuals involved in agriculture, cattle rearing and fishing and an age/sex group analysis revealed that the prevalence increased beginning in the 40-50-years-of-age group and reached 33% in both sexes in individuals over 50 years of age. Based on the described symptomatology, articular pain and headache were found to be significantly higher among infected individuals (56 and 65% prevalence, respectively, p < 0.05). Sera from volunteers were subjected to ELISA using a cocktail of recombinant proteins from Onchocerca volvulus to evaluate the specificity of the test in an endemic M. ozzardi region. No cross-reactions between M. ozzardi-infected individuals and recombinant O. volvulus proteins were detected, thus providing information on the secure use of this particular cocktail in areas where these parasites are sympatric.

Mansonella ozzardi (Nematoda: Onchocercidae) in the riverine population of the Tefé River, State of Amazonia, Brazil

Introduction: This study assessed the prevalence of Mansonella ozzardi in riverine communities of the Tefé River, Amazonas, Brazil. Methods: The prevalence of M. ozzardi was estimated by microscopic examination of thick blood smears. Results: The M. ozzardi prevalence rate was 6.3% (19/300). Filarial infection was found in 8 of the 11 communities surveyed, with prevalence rates varying from 2.5% to 22.2%. Conclusions: Tefé is a region of oil and natural gas exploration, in which there is a high turnover of workers. Migration patterns may facilitate the dissemination of mansonelliasis to other regions. .

Mansonelliasis: a brazilian neglected disease

Mansonelliasis is a filariasis whose etiological agents are Mansonella ozzardi, Mansonella perstansand Mansonella streptocerca. Only the first two cited species occur in Brazil. M. ozzardi is widely distributed in Amazonas state and it is found along the rivers Solimões, Purus, Negro and their tributaries while M. perstans is restricted to the Upper Rio Negro. In this update, we report the occurrence of M. ozzardi in Amazonas since the 1950s, and we show that over the years this filariasis has been sustained with high prevalence, while maintaining a constant cycle of transmission in endemic areas due to the lack of treatment and control policies. M. perstans has so far only been recorded in indigenous populations in the Upper Rio Negro. However, the continuous flow of migrants to other regions may cause an expansion of this infection.

A mansonelose é uma filariose cujos agentes etiológicos são Mansonella ozzardi, M. perstans e M. strepotcerca. Somente as duas primeiras ocorrem no Brasil. M. ozzardi apresenta ampla distribuição no estado do Amazonas sendo encontrada ao longo dos rios Solimões, Purus e Negro e afluentes, ao passo que M. perstans possui distribuição restrita à região do Alto Rio Negro. Nesta atualização, é relatada a ocorrência de M. ozzardi no Amazonas desde a década de 1950 e, ao longo dos anos, esta filariose tem sustentado elevadas prevalências, mantendo um ciclo constante de transmissão nas áreas endêmicas em virtude da falta de políticas de tratamento e controle. Até o momento, M. perstans só foi registrada nas populações indígenas da região do Alto Rio Negro, mas, em razão da existência de um fluxo migratório contínuo para outras regiões, existe a possibilidade de sua expansão.

Comportamiento clínico, epidemiológico y microbiológico de las filariosis en la población de Mouila en Gabón / Clinical, epidemiological and microbiological behavior of filariases in the population of Mouila, Gabon

Introducción: las filarias son nematodos pertenecientes a la familia Filariidae, aunque existen alrededor de 200 filarias parasitas, solo unas pocas parasitan al hombre. Objetivos: realizar una breve descripción de estas parasitosis, que sirviera como guía al gran número de médicos cubanos colaboradores en países africanos, donde es particularmente frecuente este padecimiento, así como describir el comportamiento de las infecciones por filarias en pacientes atendidos en el Hospital Regional de Mouila, Gabón. Métodos: se realizó un estudio observacional, descriptivo, de corte transversal. Se incluyeron 87 pacientes de los 2 sexos, de 15 años de edad y más, en los que se logró confirmar algún tipo de filariosis. Resultados: se observó que 3,7 por ciento de los pacientes presentó una filariosis, 93,1 por ciento por Loa loa, 5,7 por ciento por Mansonella perstans y 1,1 por ciento por coinfección de ambas. El grupo de más de 65 años y el sexo femenino resultaron los más afectados. El síntoma más frecuente fue el prurito (59,8 por ciento), seguido por la poliartralgia, el dolor lumbar y la astenia. La eosinofilia se apreció en 100 por ciento y la anemia fue más frecuente en pacientes parasitados con Mansonella perstans. La intensidad de la infección para ambos tipos de filarias fue baja. En 86,1 por ciento de los pacientes tratados con dietilcarbamazina y 82,4 por ciento de los tratados con ivermectina, la respuesta fue satisfactoria. Conclusiones: Loa loa predominó, sobre todo en mujeres; el prurito, la anemia y la eosinofilia fueron las manifestaciones principales, la respuesta tratamiento con ivermectina mostró ventajas

Introduction: filariae are nematodes from the family Filariidae. There are about 200 parasitic filariae, but only a few infect humans. Objectives: make a brief description of these parasitic diseases which may serve as guidance to the large number of Cuban cooperation doctors in African countries, where this condition is particularly common, and describe the behavior of filarial infections in patients cared for at Mouila Regional Hospital in Gabon. Methods: a cross-sectional observational descriptive study was conducted of 87 patients of both sexes aged 15 and over with confirmed filariasis. Results: it was found that 3.7 percent of patients had some kind of filariasis: 93.1 percent due to Loa loa, 5.7 percent due to Mansonella perstans and 1.1 percent due to coinfection by both. Females and persons over 65 were the most affected groups. The most common symptom was pruritus (59.8 percent), followed by polyarthralgia, lumbar pain and asthenia. Eosinophilia was present in 100 percent of subjects, and anemia was more frequent in patients infected with Mansonella perstans. Infection intensity was low in both filariases. The response was satisfactory in 86.1 percent of the patients treated with diethylcarbamazine and 82.4 percent of those treated with ivermectin. Conclusions: Loa loa was predominant mainly among women. Pruritus, anemia and eosinophilia were the main manifestations. Treatment with ivermectin was found to be effective

Aporte de la técnica de PCR en el diagnóstico de Mansonella ozzardi en zonas endémicas de la Argentina / Contribution of the PCR assay to the diagnosis of Mansonella ozzardi in endemic areas of Argentina

Mansonella ozzardi es un nematode parásito tisular, agente etiológico de mansonellosis en casi la totalidad de los países latinoamericanos. En Argentina la mansonellosis ha sido descrita a lo largo de la región de las yungas. Su diagnóstico microscópico puede dar resultados falsos negativos en microfilaremias bajas. El objetivo del presente estudio fue optimizar su diagnóstico molecular y comparar los resultados con los obtenidos mediante las pruebas microscópicas de Knott, de gota gruesa y de extendido hemático fino, en 92 muestras de sangre de pacientes de zona endémica. La técnica de PCR seguida de la secuenciación del producto amplificado presentó una sensibilidad del 100 % frente al método de Knott, considerado como referencia, e incluso permitió identificar 7 casos más de la parasitosis.

Mansonella ozzardi is a tissue-dwelling parasitic nematode, the causative agent of mansonelliasis in almost all Latin American countries. It has been described along the Argentine Yungas region. The microscopic diagnosis can yield false-negative test results at low microfilaremia levels. The aim of this study was to optimize the molecular diagnostic technique and compare it with the Knott's method and standard blood smear procedures (thin blood films and thick smears) in 92 blood samples of individuals from an endemic area. The PCR technique followed by the sequencing of the amplified product yielded 100 % sensitivity compared to the Knott's test, which is considered a reference method. Seven more cases of this parasitosis could only be identified with the molecular technique.

Investigation of the occurrence of Mansonella ozzardi in the State of Rondônia, Western Amazonia, Brazil / Investigação da ocorrência da Mansonella ozzardi no Estado de Rondônia, Amazônia Ocidental

INTRODUCTION: Mansonella ozzardi, a human filarial nematode transmitted by Diptera Simuliidae flies (black flies), is widely spread in the Amazon, while the occurrence of mansonelliasis in the State of Rondônia (Western Amazonia) has not been reported thus far. The existence of this parasitic disease in this state is investigated in this study. METHODS: A total of 4,452 people who lived alongside the Madeira, Mamore, Guapore, Machado and Preto Rivers, in the State of Rondônia, were examined using the thick blood smear method. Alongside the Machado and Guapore rivers, 2,112 adult simuliid specimens were captured. RESULTS: Infected people were not reported, although simuliids with vector potential such as Cerqueirellum pydanielli, C. argentiscutum and C. amazonicum were found. CONCLUSIONS: This study registered no infected people. This finding may be explained by the individuals' low level of microfilaremia that is below the limit of detection of the diagnostic method used in the study or insufficient migration of people infected with M. ozzardi from endemic areas, making it impossible to introduce the disease into Rondônia. Further studies using more sensitive diagnostic techniques could shed light on this question.

INTRODUÇÃO: Mansonella ozzardi é uma filária humana que tem como vetor dípteros simulídeos e é amplamente distribuída na Amazônia. Não há informações sobre a ocorrência de casos de mansonelose no Estado de Rondônia, e neste trabalho procurou-se investigar a situação epidemiológica desta parasitose em áreas urbanas e ribeirinhas na Amazônia Ocidental. MÉTODOS: Foram examinados 4.452 moradores às margens dos rios Madeira, Mamoré, Guaporé, Machado e Preto em Rondônia, através da técnica da gota espessa de sangue. Capturou-se às margens do rio Machado e Guaporé 2.112 simulídeos adultos das espécies Cerqueirellum pydanieli e Chirostilbia pertinax. RESULTADOS: Não foram encontradas pessoas infectadas com M. ozzardi e foram encontradas diferentes espécies de simulídeos com potencial de transmissão da mansonelose. CONCLUSÕES: Não foram encontrados indivíduos infectados com M. ozzardi neste estudo. Este fato pode ser explicado pela existência de pacientes com baixas microfilaremias, associado à técnica diagnóstica de baixa sensibilidade utilizada no estudo. Pode-se ainda aventar a possibilidade de ter ocorrido migração insuficiente de pacientes infectados de áreas endêmicas, impossibilitando a implantação da endemia. Estudos posteriores com técnicas diagnósticas mais sensíveis podem ajudar a esclarecer esta questão.

Improvement of a PCR test to diagnose infection by Mansonella ozzardi / Adequação da técnica da PCR para diagnóstico de infecção de Mansonella ozzardi

INTRODUCTION: Mansonelliasis is caused by Mansonella ozzardi. It is widespread in the Amazon region, with a high prevalence. The common exam of thick blood smears stained with Giemsa shows low efficacy levels and has been an obstacle to diagnosing individuals with low blood parasitemia. METHODS: In order to increase diagnosis efficacy, the PCR technique was improved. RESULTS AND CONCLUSIONS: PCR demonstrated the best performance, with sensitivity and negative predictive values (NPV) of 100 percent, followed by blood filtration through membrane filters, which showed a sensitivity of 88.9 percent and a NPV of 84.6 percent, when compared to thick blood smears.

INTRODUÇÃO: A mansonelose é uma filariose causada pela Mansonella ozzardi, ocorrendo na Amazônia com prevalências de até 60 por cento. A técnica de diagnóstico habitual (hemoscopia através da gota espessa) tem baixa eficácia o para o diagnóstico de pacientes com baixa parasitemia. MÉTODOS: Neste contexto foi aperfeiçoada a técnica da PCR para seu diagnóstico. RESULTADOS E CONCLUSÕES: Quando comparada à gota espessa, a PCR apresenta sensibilidade de 100 por cento, e valor preditivo negativo (VPN) de 100 por cento mostrando eficácia bastante superior à técnica da filtração em membrana que apresenta sensibilidade de 88,9 por cento e VPN de 84,6 por cento, quando também comparada à gota espessa de sangue.

Prevalence of Mansonella ozzardi among riverine communities in the municipality of Lábrea, State of Amazonas, Brazil / Prevalências de Mansonella ozzardi entre comunidades ribeirinhas do município de Lábrea, Estado do Amazonas

INTRODUCTION: Estimate the prevalence of Mansonella ozzardi infection and calculate the parasitic infection rate (PIR) in simuliid black flies in the municipality of Lábrea, State of Amazonas, Brazil. METHODS: Prevalence was measured using the thick blood smear method collected from the fingers and was related to age, sex and occupation. Simuliidae were collected with a suction apparatus, then stained with hematoxylin and dissected to verify the PIR. RESULTS: The average prevalence rate of M. ozzardi among the 694 individuals examined was 20.7 percent. Infection was higher in men (27.6 percent) than in women (14.3 percent) (p < 0.001) and occurred in most age groups, with the highest prevalence in the following age groups: 38-47 (40 percent), 48-57 (53.1 percent) and >58 (60.5 percent). The highest prevalence rates were observed in the retired (64 percent), followed by farm workers (47.1 percent). Infection by M. ozzardi was only identified in Cerqueirellum amazonicum (Simuliidae) with a PIR of 0.6 percent. CONCLUSIONS: This study showed a high prevalence of M. ozzardi in the riverine communities of Lábrea due to the lack of policies regarding the treatment of microfilaremic individuals in the region and an abundance of competent vectors for M. ozzardi.

INTRODUÇÃO: Estimar as prevalências de Mansonella ozzardi, e calcular a taxa de infecção parasitária nos simulídeos no município de Lábrea, Estado do Amazonas. MÉTODOS: As prevalências foram obtidas através do método de gota espessa a partir do sangue coletado da polpa digital e foram relacionadas com a idade, sexo e ocupação. Os simulídeos foram coletados com capturador de sucção, posteriormente foram corados com hematoxilina e dissecados para se obter a taxa de infecção parasitária. RESULTADOS: A prevalência de M. ozzardi entre as 694 pessoas examinadas foi de 20,7 por cento. A infecção foi maior nos homens (27,6 por cento) do que nas mulheres (14,3 por cento) (p < 0,001) e ocorreu na maioria das faixas etárias com maiores prevalências nos indivíduos entre 38-47 (40 por cento), 48-57 (53,1 por cento) e >58 (60,5 por cento) anos. As maiores prevalências foram observadas nos aposentados (64 por cento) e agricultores (47,1 por cento). Somente Cerqueirellum amazonicum (Simuliidae) foi encontrado infectado com M. ozzardi com uma taxa de infecção parasitária de 0,6 por cento. CONCLUSÕES: Este trabalho mostra elevadas prevalências de M. ozzardi nas comunidades ribeirinhas de Lábrea devido à ausência de políticas de tratamento dos microfilarêmicos na região e a abundância de vetores competentes.

Endemic mansonellosis in Emohua Local Government Area, Nigeria: human parasitaemia and Culicoides biting patterns.

Background & objectives: The study was aimed at elucidating the prevalence and intensity of Mansonella perstans microfilaraemia in the Emohua Local Government Area, Nigeria, and ascertaining the abundance, circadian, and the annual biting patterns of the Culicoides vector. Methods: Thick smear of 50 μl finger-prick blood stained with Giemsa was examined microscopically in a cross-sectional study. Vector landing collection on human bait was employed in a longitudinal study of the vector biting patterns, carried out between July 2005 and August 2006. Results: Of 1486 individuals examined, 11.2% of both males and females were positive for M. perstans microfilaraemia. Microfilaraemia appeared early in life. The overall geometric mean intensity among those with positive microfilaraemia was 117 mf/ml (121 mf/ml for males and 113 mf/ml for females). The differences in geometric mean intensity between different age groups were statistically significant (one-way analysis of variance; p <0.05), being highest in the oldest age group (266 mf/ml). A total of 1183 female Culicoides sp were caught from September 2005 to August 2006. The abundance of Culicoides sp was seasonal. The circadian biting activity had a broad peak between 0700 and 1200 hrs. The monthly biting rates ranged from zero bite per person per month in January 2006 to 1151 bites per person per month in June 2006. The annual biting rate was 7382 bites per person per year. Conclusion: Majority of those with positive microfilaraemia were poor socioeconomically, underscoring the need for health education and application of effective control measures against Culicoides biting midges in Emohua.

Importância do método de gota espessa de sangue no diagnóstico de filárias simpátricas no Amazonas, Brasil / The importance of thick blood film method for sympatric filarial diagnosis in Amazon basin

Esse trabalho relata os métodos de diagnósticos para filárias humanas no sangue, referindo-se a importância do método de gota espessa em relação aos métodos de filtração em membrana de policarbonato e Knott na diferenciação das espécies de microfilárias, principalmente em áreas de ocorrência de mais de uma espécie, como em regiões do Amazonas. Lâminas com microfilárias de Mansonella ozzardi foram montadas e fotografadas pelos diferentes métodos de diagnósticos. O método da gota espessa de sangue é o mais confiável, pois permite visualizar com nitidez o espaço cefálico e caudal, disposição dos núcleos caudais e formato da cauda, que são características morfológicas que diferenciam as espécies de microfilárias sanguíneas que ocorrem no Amazonas.

In this work, the visual diagnostic methods for human filarias in the blood are evaluated. The thick blood film method is more faithful to identify the microfilariae species if compared to policarbonate membrane filtration and Knott methods, especially in areas where more than one species occur, as in Amazon basin. Slides with Mansonella ozzardi microfilariae were mounted and photographed by different diagnosis methods. The thick blood film method is much easier to see the diagnostic morphological characters as cephalic and caudal space, pattern of nucleation of the tail and tail shape that can separate the blood Amazonian microfilariae species.