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.

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. .

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.

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.

Mansonella ozzardi in Amazonas, Brazil: prevalence and distribution in the municipality of Coari, in the middle Solimões River

This study investigated some epidemiological aspects of the Mansonella ozzardi in municipality of Coari, Amazonas. Clinical symptoms were correlated with the filarial infection and the parasitic infection rates (PIR) were estimated in simuliid vectors. The general M. ozzardi human prevalence rate was 13.3 percent (231/1733), of which 10.2 percent (109/1069) were from the urban area and 18.4 percent (122/664) from the rural area. The prevalence rates were higher in men (14.5 percent urban and 19.7 percent rural) than in women (6.7 percent urban and 17.2 percent rural) and occurred in most age groups. The indices of microfilaremics were higher in people > 51 years old (26.9 percent urban and 61.5 percent rural). High prevalence rates were observed in retired people (27.1 percent urban area), housewives and farmer (41.6 percent and 25 percent, respectively, in rural area). The main clinical symptoms were joint pains and sensation of leg coldness. Only Cerqueirellum argentiscutum (Simuliidae) transmits M. ozzardi in this municipality (PIR = 5.6 percent urban and 7.1 percent rural). M. ozzardi is a widely distributed parasitic disease in Coari. Thus, temporary residency in the region of people from other localities involved with the local gas exploitation might be a contributing factor in spreading the disease.

Ocorrência da Mansonella ozzardi (Nematoda, Onchocercidae) em comunidades ribeirinhas do rio Purus, Município de Boca do Acre, Amazonas, Brasil / Occurrence of Mansonella ozzardi (Nematoda, Onchocercidae) in riverine communities of the Purus river, Boca do Acre municipality, Amazonas State, Brazil

Este estudo teve o objetivo de estimar as prevalências de Mansonella ozzardi e calcular taxa de infecção parasitária nos simulídeos. O trabalho foi realizado em comunidades ribeirinhas do rio Purus, Boca do Acre, Amazonas, Brasil. As prevalências foram obtidas por meio do método de gota espessa de sangue obtido por porção digital. Os simulídeos coletados foram dissecados para estimar a taxa de infecção parasitária. A prevalência de M. ozzardi foi de 27,3 por cento (282/77). Foram observadas maiores prevalências nos homens (31,97 por cento) que nas mulheres (22,22 por cento), nos agricultores (48 por cento) e nos indivíduos entre: 38-47 (60 por cento), 48-57 (66,66 por cento) e 58-67 (75 por cento). A microfilaremia foi maior nos indivíduos entre 58-67 anos (média = 58,41mf/40µL), sexo masculino (41,44mf/40µL) e nos agricultores (49,94mf/40µL). Somente o simulídeo Cerqueirellum amazonicum foi encontrado infectado com taxa de infecção parasitária de 0,98 por cento.

The study aimed to estimate the prevalence of Mansonella ozzardi and calculate the parasitic infection rate in simuliid blackflies. The research was conducted in communities on the Purus River, Boca do Acre municipality, Amazonas State, Brazil. Prevalence was measured using the thick smear method. Captured blackflies were dissected to verify the parasitic infection rate. M. ozzardi prevalence was 27.30 percent (77/282). The study showed higher prevalence in men (31.97 percent) than women (22.22 percent), farmers (48.99 percent), and individuals in the 38-47 (60.00 percent), 48-57 (66.66 percent), and 58-67-year age brackets (75.00 percent). Microfilaremia was higher in individuals 58 to 67 years of age (average= 58.41mf/40µl), men (41.44mf/40µl), and farmers (49.94mf/40µl). Only the simuliid Cerqueirellum amazonicum was found infected with a parasitic infection rate of 0.98 percent.

Mansonella ozzardi in Brazil: prevalence of infection in riverine communities in the Purus region, in the state of Amazonas

This study was undertaken to investigate the prevalence of Mansonella ozzardi infection and to estimate the parasitic infection rate (PIR) in simuliid black flies in the municipality of Pauini, Amazonas, Brazil. We used thick blood films to examine 921 individuals in 35 riverine communities along the Pauini and Purus Rivers. Simuliids were caught in several communities. Flies were identified, stained with haematoxylin and dissected. Overall, 44 (24.86 percent) of 177 riverines were infected in communities on the Pauini River and 183 (24.19 percent) of 744 on the Purus. The prevalence was higher in men (31.81 percent and 29.82 percent) than in women (17.98 percent and 19.18 percent) and occurred in most age groups. The prevalence increased sharply in the 28-37 (50 percent and 42.68 percent) age group and increased in the older age classes. The highest prevalence was in farmers (44 percent and 52.17 percent, respectively) in the Pauini and Purus Rivers. Only Cerqueirellum amazonicum (Simuliidae) transmits M. ozzardi in this municipality, and we found a PIR of 0-8.43 percent and infectivity rate of 0-3.61 percent. These results confirm that rates of M. ozzardi infection are high in Pauini and suggest that its prevalence may be far greater than has been previously reported due to the absence of a program for treating the population.

Current profile of Mansonella ozzardi (Nematoda: Onchocercidae) in communities along the Ituxi river, Lábrea municipality, Amazonas, Brazil

The objective of this paper was to describe the current status of Mansonella ozzardi prevalence among the inhabitants of 12 communities along the Ituxi river, in Lábrea municipality, state of Amazonas. The prevalence of M. ozzardi was determined using thick blood smears obtained by digital punctures. M. ozzardi was found in 30.23 percent of the samples collected (39/129), with similar prevalence between genders (males: 30.30 percent; females: 30.16 percent); the highest prevalence was found in homemakers (45.45 percent) followed by farmers (38.77 percent). Among age groups, males and females older than 48 exhibited the highest rates. These results show a significative increase in the prevalence when compared to a epidemiological study made 26 years ago in the same area as well as a different epidemiological profile (gender and occupation) in relation to other areas in Amazonas.

The feasibility of a bed net impregnation program to enhance control of Malayan filariasis along a swamp forest in southern Thailand.

The purpose of this study is to document the potential feasibility of using a bed net impregnation program to enhance the control of Malayan filariasis in southern Thailand. A survey was conducted in one Muslim and one Buddhist village along the swamp forest in Narathiwat Province. Face-to-face interview was employed to collect data on practice of bed net use, knowledge and attitudes on filarial control and acceptance if a bed net impregnation program were to be introduced. Bed nets were used by 98.5% of the study households. Both Muslims and Buddhists were all in bed by 23.00 hrs. By 03.00 hrs, more than 20% of Buddhists were out of bed for rubber tapping, whereas more than 90% of the Muslim were still in bed until 04.30 hrs. Combining our data with biting rate from a previous study, approximately one-third of Mansonia bites were protected by the current bed net practice. The impregnation program was potentially welcome by both groups of villagers. From this study, we conclude that a bed net impregnation program in this area is feasible.

Prevalencia de mansonelosis en comunidades del río Atabapo del departamento de Guainía, Colombia / Prevalence of mansonellosis in communities of the River Atabapo, Guainía Department, Colombia

En el departamento de Guainía, Colombia, se realizó un estudio tipo encuesta de prevalencia de corte en siete comunidades del río Atabapo, donde se calculó una muestra poblacional de 181 personas mayores de 10 años que se debían examinar. Se les tomó muestra de sangre que se examinó mediante cuatro técnicas (examen en fresco, gota gruesa, prueba de Knott y conteo po c.c.), examen médico, estudio de saneamiento y encuesta por vivienda. Se encontró una prevalencia de 57 por ciento en el grupo examinado que, por ser muestra representativa de la población, se puede decir que es la prevalencia de la zona. Se tomó como unidad de análisis a 37 viviendas escogidas aleatoriamente. Existe una relación dada por la razón de prevalencia entre la presencia de la enfermedad con la ocupación de ser agricultor y síntomas como cefalea, dolor en el cuello, escalofríos y decaimiento, que fueron estadísticamente significativas. De las pruebas diagnósticas utilizadas, además de la prueba de Knott, el conteo por cc fue la que mejor resultado brindó en el estudio. Las condiciones de saneamiento ambiental en la zona fueron muy similares y no permitieron detectar diferencias entre las comunidades estudiadas. Se trató de tomar muestras entomológicas para la identificación de vectores que no se puedieron identificar plenamente

Comparación de pruebas de diagnóstico de mansonelosis en el estudio de prevalencia en comunidades del río Atabapo, departamento del Guainía, Colombia 1996 / Comparison of mansonellosis diagnostic test in a prevalency study in communities situated along the River Atabapo in the Guainía Department, Colombia, 1996

En el departamento de Guainía, Colombia, se realizó un estudio tipo encuesta de prevalencia de corte en siete comunidades del río Atabapo, donde se calculó una muestra poblacional de 181 personas mayores de 10 años que se debían examinar, tomando, como unidad de análisis, 37 viviendas escogidas aleatoriamente. Se les tomó una muestra de sangre que se examinó mediante cuatro técnicas (examen en fresco, gota gruesa, prueba de Knott y conteo por cm cúbicos), examen médico, estudio de saneamiento y encuesta por vivienda. Se encontró una prevalencia de 57 por ciento en el grupo examinado que, por ser muestra representativa de la población, se puede decir que es la prevalencia de la zona. De las tres pruebas diagnósticas utilizadas, además de la prueba de knott, el conteo por cm cúbicos fue la que mejor resultado brindó en el estudio, dando una sensibilidad, especificidad y valor predictivo positivo similar y mejor que la de la prueba de oro que se tomó como referencia

Mansonelosis en el area Sur-oriental de la Orinoquia Venezolana / Mansonelliasis in the southeast Venezuelan Orinoquia region

Physical exam and skin biopsy were performed and peripheral blood samples drawn from 10 of the inhabitants of 26 jungle villages of the State of Bolívar, Venezuela. One hundred and fifty three Indians and an inhabitant of mixed blood from 13 different communities were found to be infected with mansonelliasis representing a global index of 36.40 in the endemic area. The parasitosis was found to be concentrated in three areas. The largest, located in the southwest of the country and forming part of an extent infected area embarking neighboring parts of Venezuela and Brazil, contains villages with a parasite index of 80.76 and 94.44. A second focus is located in the southeast, its carriers, as those of the first, are infected with Mansonella ozzardi. In a third, central eastern focus infections with Mansonella pertans were found. The patients infected with M. ozzardi were apparently asymptomatic and their physical exam was normal, even though individual parasite densities up to 30,000 microfilariae/ml blood and 22,000/gr skin were found.

Mansonella ozzardi en el Darién (Panamá) / Mansonella ozzardi in Darien (Panama)

La prevalencia de la filaria humana Mansonella ozzardi entre los indígenas residentes en tres aldeas ubicadas a lo largo del río Chucunaque en la Provincia de Darién, Panamá, se evaluó mediante el examen de 25 microlitros de sangre capilar extraída del lóbulo de la oreja de cada persona. Se examinó una gota gruesa teñida con Giensa y se observó la característica microfilaria. En Mortí, de 123 personas analizadas, 83 (67.5%) resultaron microfilarémicas; en Uala, de 60, 11 (18.3%); y en Membrillo, de 129 personas, 14 (10.9%) resultaron positivas. En Mortí se obtuvo, en la recogida periódica de simúlidos (Díptera: Simuliidae) que eran considerados posibles vectores de la filaria, un promedio de 398 simúlidos por hora por hombre. Todos estos simúlidos fueron recogidos en el momento de picar a una persona e identificados como Simulium sanguineum. En la disección de los simúlidos silvestres se observaron larvas de tercera fase, en la cápsula cefálica del simúlido, después de siete días de capturados al momento de haber ingerido sangre de personas infectadas. La larva de la tercera fase es la forma infectante para humanos y puede ser transmitida al momento de la picadura del simúlido. El grado de infectividad de esas larvas no fue determinado en este estudio. Hemos llegado a la conclusión de que el S. sanguineum es un vector potencial de M. ozzardi en la Provincia de Darién, Panamá

Mansonelose / Mansonellasis

Analisa-se, a incidência da mansonelose na Amazônia, seguramente, a única filariose humana autóctone, constatada entre as populaçöes indígenas. Apresentam-se, dados estatísticos, sobre a prevalência "Mansonella Ozzardi" em índios Ticunas do Alto Solimöes, Estado do Amazonas, em 1975

Filariasis en Colombia: presencia de Dipetalonema perstans en la Comisaria del Guainia / Filariasis in Colombia: presence of Dipetalonema perstans in the Comisaria del Guainia

Al examinar 75 muestras de sangre (metodo de Knott) colectadas en Puerto Inirida, Coco y Pajuil en la Comisaria del Guainia, Colombia, se descubrieron 26 portadores de micofilarias. En 18 personas habia unicamente Mansonella ozzardi; 3 tenian infeccion con M. ozzardi; 3 tenian infeccion con M. ozzardi y Dipetalonema perstans; y cinco solo con D. perstans. La infeccion por M. ozzardi se observo en blancos y en indigenas de las tribus curripacos, puinaves, tukanos, guananos y salivas, pero D. perstans se encontro solamente entre los curripacos. El numero de microfilarias (mf) circulantes fue bajo, 73% de los portadores tenian menos de 200 mf/ml de sangre; las personas que presentaron unicamente D. perstans tenian menos de 310 mf/ml. Estos resultados confirman la presencia de D. perstans en Colombia y sugieren que su prevalencia y distribucion en la Comisaria del Guainia y areas cercanas pueden ser mas altas de lo que se ha sospechado hasta el momento