Mansonella ozzardi in Brazil: prevalence of infection in riverine communities in the Purus region, in the state of Amazonas (original) (raw)
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Revista da Sociedade Brasileira de Medicina Tropical, 2011
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%. Infection was higher in men (27.6%) than in women (14.3%) (p < 0.001) and occurred in most age groups, with the highest prevalence in the following age groups: 38-47 (40%), 48-57 (53.1%) and >58 (60.5%). The highest prevalence rates were observed in the retired (64%), followed by farm workers (47.1%). Infection by M. ozzardi was only identified in Cerqueirellum amazonicum (Simuliidae) with a PIR of 0.6%. 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.
Revista da Sociedade Brasileira de Medicina Tropical, 2011
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.
Memórias do Instituto Oswaldo Cruz, 2014
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.
Memórias do Instituto Oswaldo Cruz, 2014
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.
High Prevalence of Mansonella ozzardi Infection in the Amazon Region, Ecuador
Emerging Infectious Diseases, 2019
We reviewed Giemsa-stained thick blood smears, obtained through the national malaria surveillance program in the Amazon region of Ecuador, by light microscopy for Mansonella spp. microfilariae. Of 2,756 slides examined, 566 (20.5%) were positive. Nested PCR confirmed that the microfilariae were those of M. ozzardi nematodes, indicating that this parasite is endemic to this region. A lthough mansonelliases is probably the most prevalent filarial infection worldwide, it is the least studied and is considered a neglected parasite infection (1,2). Human infection with members of the filarial nematode genus Mansonella, including M. ozzardi, M. perstans, and M. streptocerca nematodes, is common and widespread in the Western Hemisphere and Africa. M. ozzardi nematodes are found exclusively in the Western Hemisphere from southern Mexico to northwestern Argentina but have not been reported in Ecuador, Chile, Uruguay, and Paraguay (1,2). M. perstans infections are found mainly in sub-Saharan Africa, with sporadic cases in a few countries in South America, whereas M. streptocerca infections are found only in Africa (1-4). Epidemiologic studies have reported that M. ozzardi nematodes are highly prevalent in the Amazon Basin (Brazil, Colombia, Peru, Bolivia, Venezuela, and Argentina) and on some Caribbean islands. In the general population, the prevalence rate of infection ranges from 0% to 46%; however, in some areas it is 92.3% (2). Community health workers from the malaria control program in the Amazon region of Ecuador have reported that filaria-like nematodes are seen in thick blood smears, suggesting the presence of a Mansonella sp. in this area. Mansonella spp. nematodes are transmitted by dipteran flies. In particular, M. ozzardi nematodes are transmitted by biting midges of the genera Culicoides and by black flies from the genus Simulium (1). Both of these vectors are present in the Amazon region of Ecuador (Renato Leon, Universidad San Francisco de Quito, pers. comm., 2018 Dec 5).
Acta Amazonica, 2004
Mansonella ozzardi is transmitted by two dipterian families, Ceratopogonidae (midges) and Simuliidae (black flies). In Brazil, black flies are vectors for this filariasis until now. In this paper, we determined the seasonality, parity capacity and parasitic infection rate of Cerqueirellum argentiscutum. The work was carried out in the Porto Japão community, Lower Solimões River, Amazonas, Brazil. Results show that the black flies were more abundant during the rainy season (from December to May). The number of parous flies was higher in every sampling during the course of year. Monthly Biting Rate (MBR1 123742.00, MBR2 86701.50) was high, although Parasitic Infection Rate (PIR1 0.06, PIR2 0.08) and Annual Transmission Potential (ATP 7.25) were low in numbers.
Transfusion, 2018
BACKGROUNDIn the Brazilian Amazon, the filarial nematode Mansonella ozzardi co‐exists with malaria parasites and thick blood smear microscopy is considered the diagnostic gold standard. Transfusion of M. ozzardi microfilariae does not establish new infections, however microfilariae can survive approximately 2 years in blood‐recipients with unknown risk of pathology. Data on transfusion‐transmitted filariasis are lacking. This study investigated M. ozzardi parasitemias in blood donors from decentralized centers of “Fundação Hematologia e Hemoterapia do Estado do Amazonas/HEMOAM,” Northern Brazil.STUDY DESIGN AND METHODSCross‐sectional investigation employing blood smear microscopy (n = 356) and qualitative nested‐M. ozzardi‐PCR (227 out of 356) in donor candidates from 19 hemocenters in interior/rural municipalities of Amazonas state. FINDINGS: Participants were mostly young males. Positivity by microscopy was 7.9% (28 out of 356) and 23.8% by M. ozzardi‐PCR (54 out of 227). Parasita...
Revista da Sociedade Brasileira de Medicina Tropical, 2016
Introduction: Mansonella ozzardi is a widely distributed fi laria worm in the Amazon region. This study aimed to determine the prevalence of M. ozzardi infection in riverine communities of Lábrea municipality, Amazonas State, Brazil. Methods: A diagnostic blood fi ltration method in a polycarbonate membrane was used. Results: M. ozzardi was found in 50.3% of the sample, with the highest prevalence in farmers/fi shermen (69.4%; χ 2 = -19.14, p<0.001). The prevalence was higher in longerterm residents (≥11 years; 60.2%). Conclusions: M. ozzardi infection rates are high near the Purus River, much greater than those previously reported based on diagnosis using thick blood smears.