Filarial disease in the Brazilian Amazon and emerging opportunities for treatment and control.

Following the successful eradication of Wuchereria bancrofti, there are now just three species of conventional microfilaremic human filarial parasites endemic to the Brazilian Amazon region: Mansonella ozzardi, Mansonella perstans and Onchocerca volvulus. The zoonotic filarial parasite Dirofilaria immitis is also found in the Amazon region as are several sylvatic filarial parasites, some of which have been recorded causing zoonoses and some of which have never been recorded outside the region. Onchocerca volvulus is only found in the Amazonia onchocerciasis focus in the Brazilian state of Roraima where it affects the people of the Yanomami tribe living around the densely forested Venezuela border region. Mansonella ozzardi is by far the most common filarial parasite in Brazil and has a broad but patchy distribution throughout the western Amazon region. Recorded in the Brazilian states of Acre, Roraima, Matto Grosso, and within almost every municipality of Amazonas state, it is believed that pollution of the urban stream and river systems prevents the development of the simuliid vectors of M. ozzardi and explains the parasite's reduced distribution within urban areas and an absence of recent reports from the state capital Manaus. Decades of WHO-led periodic ivermectin treatment of Yanomami tribe's people have resulted in the partial suppression of O. volvulus transmission in this focus and has also probably affected the transmission of M. ozzardi in the region. Mansonella perstans, O. volvulus and very probably M. ozzardi infections can all be treated and most likely cured with a 4-6-week treatment course of doxycycline. The Brazilian Ministry of Health does not, however, presently recommend any treatment for mansonellosis infections and thus parasitic infections outside the Amazonia focus are typically left untreated. While the long treatment courses required for doxycycline-based mansonellosis therapies preclude their use in control programmes, new fast-acting filarial drug treatments are likely to soon become available for the treatment of both onchocerciasis and mansonellosis in the Amazon region. Filarial disease management in the Brazilian Amazon is thus likely to become dramatically more viable at a time when the public health importance of these diseases is increasingly being recognized.

Dirofilaria immitis parasite infection in cats: first case reported in the Legal Amazon region, Brazil: case report / Infecção por Dirofilaria immitis em gato: primeiro registro na região da Amazônia Legal, Brasil: relato de caso

A case of infection with Dirofilaria immitis in a cat is reported here with clinical signs of apathy, anorexia, dyspnea, polypnea, slight dehydration and pale mucus membranes. The radiographic examination showed cardiomegaly, lobar arteries dilation of the cranial lobes and tortuosity, enlargement of the caudal lobar arteries. In the right lobe of the lung parenchyma, interstitial pulmonary opacification tending to alveolar opacification was seen. The clinical signs, the movements, and the morphology of the microfilariae in the direct examination of fresh blood, peripheral blood smear and Knott's modified test supported the diagnosis. We alert to the need for clinicians to consider feline heartworm diseases as a differential diagnosis in endemic areas when cats show respiratory signs.

Descreve-se um caso de infecção por Dirofilaria immitis em gato com sinais clínicos de apatia, anorexia, dispneia, polipneia, leve desidratação e mucosas pálidas. O exame radiográfico demonstrou cardiomegalia, dilatação da artéria lobar cranial e tortuosidade, alargamento dos lobos caudais da artéria lobar. No lobo direito do parênquima pulmonar, opacificação pulmonar intersticial tendendo à opacificação foi observada. O diagnóstico foi baseado nos sinais clínicos, nos movimentos e na morfologia das microfilárias detectadas no exame de sangue a fresco, no esfregaço de sangue periférico e no teste de Knott modificado. Alertou-se para a necessidade de os clínicos considerarem a dirofilariose felina como diagnóstico diferencial em áreas endêmicas quando os gatos apresentam sinais respiratórios.

Correlated prevalence of hydrocele and microfilaremia in Amazon (Belém, 1951-2005).

BACKGROUND & OBJECTIVES: For decades, the city of Belém in Brazil's eastern Amazon was the second city in the country with highest prevalence of cases of filariasis due to Wuchereria bancrofti infection. However, this prevalence decreased over time until reaching null records, concomitantly with a decrease in frequency of recorded hydrocele cases. In this context, we analyzed cross-sectional data to evaluate the degree of correlation between prevalence of positive blood microfilariae results during surveillance screening occurred along 54 years (1951-2005) and prevalence of hydrocele cases recorded in the same time period. METHODS: The dataset regarding hydrocele cases was obtained from two local hospitals. The Endemic Diseases Control Division of the Health Surveillance Department of the Municipal Health Department of Belém provided dataset regarding positive blood microfilariae cases. Prevalence calculus and linear correlation statistics were performed. RESULTS: Both positive blood microfilariae and hydrocele cases are well correlated statistically in absolute frequency (r = 0.871, 95%CI = 0.788 to 0.923, R2 = 0.759, p < 0.0001) and in prevalence (r = 0.835, 95%CI = 0.732 to 0.901, R2 = 0.698, p < 0.0001). INTERPRETATION & CONCLUSION: We have concluded that blood microfilariae detection and hospitalized hydrocele cases are well correlated in our dataset. In addition, these results support the hypothesis that hydrocele prevalence can be useful to filariasis surveillance and control in endemic areas. However, limitations to hydrocele prevalence as an epidemiological indicator of filariasis are evidenced.

Vector-borne diseases in Haiti: a review.

Haiti lies on the western third of the island of Hispaniola in the Caribbean, and is one of the poorest nations in the Western hemisphere. Haiti attracts a lot of medical attention and support due to severe natural disasters followed by disastrous health consequences. Vector-borne infections are still prevalent there with some unique aspects comparing it to Latin American countries and other Caribbean islands. Although vector-borne viral diseases such as dengue and recently chikungunya can be found in many of the Caribbean islands, including Haiti, there is an apparent distinction of the vector-borne parasitic diseases. Contrary to neighboring Carribbean islands, Haiti is highly endemic for malaria, lymphatic filariasis and mansonellosis. Affected by repeat natural disasters, poverty and lack of adequate infrastructure, control of transmission within Haiti and prevention of dissemination of vector-borne pathogens to other regions is challenging. In this review we summarize some aspects concerning diseases caused by vector-borne pathogens in Haiti.

Valoración clínica y parasitológica del tití gris (Primates: Cebidae: Saguinus leucopus) en dos poblaciones naturales presentes en San Carlos y San Rafael (Antioquia, Colombia) / Clinical and parasitological evaluation of White-footed Tamarins (Primates: Cebidae: Saguinusleucopus) from two free-range populations located in San Carlos and San Rafael (Antioquia, Colombia) / Valoração clínica e parasitológica do sagui cinza (Primates: Cebidae: Saguinus leucopus) em duas populações naturais que se encontram em San Carlos e San Rafael (Antioquia, Colômbia)

Resumen El estudio de individuos en cautiverio de primates Neotropicales ha permitido conocer aspectos básicos de su historia natural. Sin embargo las condiciones medioambientales pueden determinar diferencias ecológicas y fisiológicas en poblaciones silvestres. En el caso del tití gris (Saguinus leucopus), primate endémico del noroccidente colombiano, diferentes parámetros fisiológicos han sido evaluados en cautiverio. Con el fin de diagnosticar el estado de salud en condiciones naturales, se evaluaron varias características externas y parámetros fisiológicos, así como la comunidad de parásitos de dos poblaciones naturales. Aunque en general no se detectaron signos de deterioro en las condiciones generales de salud, se identificaron once taxones de parásitos entre helmintos y protozoos, algunos con alta prevalencia (filarias y Trypanosoma spp). Las comunidades de parásitos en cautiverio y en estado silvestre muestran diferencias notables. Igualmente, se identificó una aparente variación entre poblaciones silvestres e incluso entre grupos sociales circundantes con respecto a los perfiles hematológicos y de química sanguínea, que sugiere diferencias en la respuesta fisiológica ante condiciones medioambientales. Ninguna de dichas variables fisiológicas pareció estar relacionada con los parásitos encontrados. Los resultados revelaron una amplia diversidad de parásitos y una elevada tasa de infecciones parasitarias en poblaciones naturales de S. leucopus, que parecen no estar asociadas con indicadores de la condición de salud. Futuros estudios deberán enfatizar en aspectos ecológicos, genéticos y demográficos que determinen las condiciones de salud de S. leucopus en su medio natural. Se recomienda que la rehabilitación de individuos en cautiverio tenga presente posibles diferencias en variables fisiológicas y epidemiológicas entre poblaciones naturales y grupos en cautiverio con el fin de restringir la transmisión de agentes infecciosos entre ...

Abstract While much of the natural history of Neotropical primates has been revealed through studies conducted in captive individuals, environmental factors may impose ecological and physiological differences in free-range populations. For the white-footed tamarin (Saguinus leucopus), a primate endemic to Northwest Colombia, physiological parameters that have been assessed in captivity still remain to be measured in free-range populations. In order to diagnose the health status of this species in a natural environment, we assessed several external traits, measured hematological and blood-chemistry values, and characterized the parasite community of two natural populations. Despite the identification of eleven different parasite taxa and wide distribution of filaria and Trypanosoma spp., we faieled to detect signs of poor health condition. Substantial differences were found between captive and free-range tamarin populations in the composition of their parasite communities. Likewise, hematological and blood-chemistry profiles differed between free-range populations and even between neighboring social groups, suggesting a role of environmental factors in the physiological response. However, none of the physiological parameters varied as a response to parasite infection. Our results revealed a high diversity of parasites and elevated rates of parasitic infections in natural populations of S. leucopus, that do not seem to be associated with indicators of health conditions. Future studies should emphasize on ecological, genetic and demographic factors that determine the health conditions of S. leucopus in the wild. Lastly, geographic variation of physiological profiles and parasite distribution, as well as epidemiological differences between captive and wild populations, should be incorporated in rehabilitation plans of captive tamarins in order to restrict the transmission of infectious agents between populations.

Resumo O estudo de indivíduos em cativeiro de primatas Neotropicais tem permitido conhecer aspectos básicos da história natural. Embora as condições ambientais podem determinar diferenças ecológicas e fisiológicas em populações silvestres. No caso do sagui cinza (Saguinus leucopus), primata endémico do noroeste colombiano, diferentes parâmetros fisiológicos tem sido avaliados em cativeiro. Com o intuito de diagnosticar o estado de saúde em condições naturais, avaliaram-se vários rasgos externos e parâmetros fisiológicos, assim como a comunidade de parasitas de duas populações naturais. Ainda que em geral não se detectassem signos de deterioro nas condições gerais de saúde, identificaram-se onze táxones de parasitas entre helmintos e protozoários, alguns com alta prevalência (filarias e Trypanosoma spp). As comunidades de parasitas em cativeiro e no estado silvestre mostram diferenças notáveis. Igualmente, identificou-se uma aparente variação entre populações silvestres e entre grupos sociais circundantes com respeito aos perfis hematológicos e de química sanguínea, que sugere diferenças na resposta fisiológica diante condições ambientais do médio. Nenhuma das mencionadas variáveis fisiológicas pareceu estar relacionada com as parasitas encontradas. Os resultados revelaram uma grande diversidade de parasitas e uma alta taxa de infecção parasitária em populações naturais de S. leucopus, que não parecem estar associados com indicadores do condição de saúde. Estudos deste tipo no futuro deveram enfatizar em aspectos ecológicos, genéticos e demográficos que determinem as condições de saúde de S. leucopus em seu médio natural. Recomenda-se que a reabilitação de indivíduos em cativeiro tenha presente possíveis diferenças em variáveis fisiológicas e epidemiológicas entre populações naturais e grupos em cativeiro com o fim de restringir a transmissão de agentes infeciosos entre populações.

Mortality by filarial nematodes in passeriformes of species Oryzoborus maximiliani in Brazil

Descreve-se a ocorrência de filariose em passeriformes da espécie Oryzoborus maximiliani (bicudo) mantidos em cativeiro. Os sinais clínicos incluiram insuficiência respiratória e prostração, evoluindo para decúbito lateral e morte. Todos os indivíduos capturados adoeceram e morreram em poucos dias. As lesões mais significativas foram encontradas nos pulmões, que estavam acinzentados na região adjacente ao saco aéreo abdominal. Impressões do pulmão observadas ao microscópio em 100 aumentos permitiram a visualização de grande número de formas alongadas típicas de nematódeo. Considerando suas dimensões e os relatos da literatura consultada, especulou-se a possibilidade de filariose. As condições de estresse de captura e cativeiro podem ser determinantes do quadro agudo observado, o que permite sugerir esta suspeita em casos semelhantes. Considera-se importante, entretanto, a possibilidade de a manifestação clínica na forma crônica ou assintomática poder ser mais comum que a aguda.