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 in pet dogs from the metropolitan area of the Colombian Caribbean.

A cross-sectional study was carried out to determine the frequency and factors associated with Dirofilaria immitis infection in pet dogs in the metropolitan area of the Colombian Caribbean (northern Colombia). A total of 173 dogs were analyzed by a commercial rapid immunochromatographic test (RIT) and a nested PCR of the cytochrome oxidase subunit I gene, in parallel. Ninety-two (53.2%) of the dogs showed positive results to the RIT, while 59 (34.1%) animals had D. immitis DNA by PCR. Positivity to one or both diagnostic techniques was detected in 104 (60.1%; CI95%: 53.8-67.4) of the sampled dogs. In PCR-positive dogs, phylogenetic analyses evidenced high nucleotide identity (100%) with sequences previously obtained from mosquitoes, dogs and other mammals in different countries. Exercise intolerance (p = 0.002; OR: 2.33; CI95%: 1.37-3.96) and thrombocytopenia (p = < 0.001; OR: 1.95; CI95%: 1.11-3.43) were the main factors associated with D. immitis infection in dogs. The high frequency of D. immitis in dogs indicates a wide distribution of this parasite in the metropolitan area of the Colombian Caribbean, which can be of animal and public health concern. Our results highlight the need to combine different methods to increase the diagnostic accuracy of D. immitis.

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.

Dirofilaria immitis is endemic in rural areas of the Brazilian Amazonas state capital, Manaus / Dirofilaria immitis é endêmica em áreas rurais da capital do estado do Amazonas, Manaus

The canine filarial parasite Dirofilaria immitis has not been reported in Brazil´s Amazonas state capital, Manaus, for over a century. Here, we report one imported and 27 autochthonous D. immitis infections from a microfilarial survey of 766 domestic dog blood samples collected between 2017 and 2021 in Manaus. An Overall prevalence estimate of 15.44% (23/149) was calculated from our two rural collection sites; a prevalence of 1.22% (4/328) was estimated at our periurban collection site, and an overall prevalence of 0.35% (1/289) was calculated from our two urban clinic collections. Our data suggest that in the urban areas of Manaus, where the parasites are very likely vectored by the same species of mosquito that historically vectored Wuchereria bancrofti (Culex quinquefasciatus), prevalence levels are very low and possibly maintained by an influx from rural areas where sylvatic reservoirs and/or more favorable vector transmission dynamics maintain high prevalences.(AU)

O parasita filarial canino, Dirofilaria immitis, causa doença zoonótica, mas não tem sido registrado em Manaus, capital do estado do Amazonas, há mais de um século. Neste trabalho, foi relatado uma infecção por D. immitis alóctone e 27 autóctones de um levantamento de microfilárias em 766 amostras de sangue em cães domésticos, coletados entre 2017 e 2021 em Manaus. A prevalência de 15,44% (23/149) foi estabelecida em áreas rurais, 1,22% (4/328) para áreas periurbanas e de 0,35% (1/289) para duas clínicas veterinárias localizadas na zona urbana da cidade. Estes dados sugerem, portanto, que nas áreas urbanas de Manaus, nas quais o parasita é provavelmente vetorizado pela mesma espécie de mosquito que, historicamente, transmitiu Wuchereria bancrofti (Culex quinquefasciatus). Também os níveis de prevalência são baixos e, possivelmente, mantidos por um influxo de áreas rurais onde reservatórios silvestres e/ou dinâmicas de transmissão vetorial mais favoráveis mantêm uma prevalência mais elevada.(AU)

The emergence of Dirofilaria repens in a non-endemic area influenced by climate change: dynamics of transmission using a mathematical model.

Dirofilaria repens is a nematode affecting domestic and wild canids, transmitted by several species of mosquitoes of different genera. It usually causes a non-pathogenic subcutaneous infection in dogs and is the principal agent of human dirofilariasis in the Old World. The geographic distribution of D. repens is changing rapidly, and several factors contribute to the spread of the infection to non-endemic areas. A mathematical model for transmission of Dirofilaria spp. was built, using a system of ordinary differential equations that consider the interactions between reservoirs, vectors, and humans. The transmission simulations of D. repens were carried out considering a projection in time, with intervals of 15 and 100 years. For the dynamics of the vector, seasonal variations were presented as series with quarter periodicity during the year. The results of the simulations highlight the peak of contagions in the reservoir and in humans, a product of the action of the vector when it remains active throughout the year. A 300% infection increase in the reservoir was observed during the first decade and remains present in the population with a representative number of cases. When the vector maintains its density and infectivity during the year, the incidence of the infection in humans increases. Accumulated cases amount to 45 per 100,000 inhabitants, which corresponds to a cumulative incidence of 0.05%, in 85 years. This indicates that early prevention of infection in canids would significantly reduce the disease, also reducing the number of accumulated cases of human dirofilariasis by D. repens. The interaction between the simulations generated by the model highlights the sensitivity of the epidemiological curve to the periodicity of seasonality, reaffirming the hypothesis of the probability of movement of the zoonotic disease to non-endemic areas, due to climate change.

Report of Dirofilaria immitis infection with acute cardiopulmonary complications in a cat from Northeastern Brazil / Relato de infecção por Dirofilaria immitis com complicações cardiopulmonares agudas em um gato no Nordeste do Brasil

Dirofilariasis is a zoonotic disease caused by Dirofilaria immitis, a nematode found mainly in the pulmonary artery and right chambers of the heart, lungs, and large vessels of dogs. This parasitism also occasionally occurs in cats, causing an amicrofilaremic and asymptomatic infection, resulting in severe illness and rapid death. In this case report, it was described acute clinical signs and histopathological alterations in a domestic cat with heartworm disease from the city of Mossoró, the Rio Grande do Norte, Brazil. The nematode species, D. immitis, was confirmed by morphological and molecular analyses. This is the first documented and full report of feline heartworm disease in northeastern Brazil.(AU)

A dirofilariose é uma doença zoonótica causada por Dirofilaria immitis, um nematódeo que parasita cães, principalmente a artéria pulmonar e as câmaras direitas do coração, pulmões e grandes vasos. Este parasita também ocorre ocasionalmente em gatos, geralmente causando uma infecção amicrofilarêmica e assintomática, que pode resultar em doença grave e morte rápida. Neste relato de caso, são apresentados os sinais clínicos agudos e alterações histopatológicas em um gato doméstico do município de Mossoró, Rio Grande do Norte, Brasil, com dirofilariose. A espécie de nematóide, D. immitis, foi confirmada por análises morfológicas e moleculares. Este é o primeiro relato documentado e completo de dirofilariose felina no Nordeste do Brasil.(AU)

Report of Dirofilaria immitis infection with acute cardiopulmonary complications in a cat from Northeastern Brazil / Relato de infecção por Dirofilaria immitis com complicações cardiopulmonares agudas em um gato no Nordeste do Brasil

Dirofilariasis is a zoonotic disease caused by Dirofilaria immitis, a nematode found mainly in the pulmonary artery and right chambers of the heart, lungs, and large vessels of dogs. This parasitism also occasionally occurs in cats, causing an amicrofilaremic and asymptomatic infection, resulting in severe illness and rapid death. In this case report, it was described acute clinical signs and histopathological alterations in a domestic cat with heartworm disease from the city of Mossoró, the Rio Grande do Norte, Brazil. The nematode species, D. immitis, was confirmed by morphological and molecular analyses. This is the first documented and full report of feline heartworm disease in northeastern Brazil.(AU)

A dirofilariose é uma doença zoonótica causada por Dirofilaria immitis, um nematódeo que parasita cães, principalmente a artéria pulmonar e as câmaras direitas do coração, pulmões e grandes vasos. Este parasita também ocorre ocasionalmente em gatos, geralmente causando uma infecção amicrofilarêmica e assintomática, que pode resultar em doença grave e morte rápida. Neste relato de caso, são apresentados os sinais clínicos agudos e alterações histopatológicas em um gato doméstico do município de Mossoró, Rio Grande do Norte, Brasil, com dirofilariose. A espécie de nematóide, D. immitis, foi confirmada por análises morfológicas e moleculares. Este é o primeiro relato documentado e completo de dirofilariose felina no Nordeste do Brasil.(AU)

PREVALENCE AND MOLECULAR CHARACTERIZATION OF DIROFILARIA IMMITIS (FILARIOIDEA: ONCHOCERCIDAE) IN DOGS FROM ENDEMIC AREAS OF RIO DE JANEIRO STATE, BRAZIL.

Canine dirofilariasis is common in Brazil, but molecular diagnosis is rare even though molecular studies increase our knowledge about molecular epidemiology and circulating genotypes from helminths worldwide. This study aims to estimate the prevalence of infection with a modified Knott's test and to perform molecular characterization of Dirofilaria immitis (Leidy, 1856) Railliet and Henry, 1911, in dogs from endemic areas of Maricá and Niterói municipalities, Rio de Janeiro State, Brazil. Molecular characterization was performed in 33 blood samples from dogs positive for microfilariae and 4 adult worms obtained from 2 other dogs. DNA extraction followed by PCR for mitochondrial target 12S rDNA and cytochrome oxidase subunit 1 (COI) of D. immitis were performed, and the amplified products were sequenced. All sequences were identical for both gene targets and showed 100% identity with D. immitis sequences from different animal species from various countries. The study concluded that this genotype of D. immitis might be dispersed worldwide.

Human pulmonary dirofilariasis with secondary myocarditis

Abstract Dirofilariasis is a little-known zoonosis, with dogs and cats as definitive hosts. It is caused by nematodes and transmitted by mosquito bites. We report the case of a 67-year-old man with a consumptive syndrome with two subpleural pulmonary opacities. A transthoracic lung biopsy revealed a Dirofilaria worm. Myocardial nuclear magnetic resonance (NMR) demonstrated dilated cardiomyopathy after myocarditis related to dirofilariasis. Human infection is rare and occurs accidentally. The most common radiological alteration is a mainly subpleural coin lesion. Dirofilariasis is a neglected emergent disease and knowledge about it is important for differential diagnoses from neoplastic pulmonary nodules.

Melanization of Dirofilaria immitis Larvae in Different Culicid Species.

BACKGROUND: Dirofilaria immitis is an important filarioid transmitted by culicids. The vector role of these arthropods may be influenced by biological events as melanization against D. immitis larvae. This study aimed to detect the occurrence of melanization in Culex quinquefasciatus, Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus experimentally infected with D. immitis. METHODS: Five populations (Cx. quinquefasciatus RECIFE (P1), Ae. albopictus RECIFE (P2), Ae. aegypti RECIFE (P3), Ae. aegypti CAMPINAS (P4) and Ae. aegypti ROCKEFELLER (P5)) were artificially fed with infected blood containing D. immitis microfilariae. Ten mosquitoes per day from each population were dissected for 14 days. RESULTS: Melanized larvae of D. immitis were observed in all population except in P3. The period in which melanized larvae were found varied from the third to the 14th day post-infection. Difference in the number of these larvae was observed between P5 and P2-P3 (P< 0.01), and between P5 and P4 (P< 0.05). Third-stage larvae of D. immitis were detected in all population 14 d post-infection, except in P3, which presented high mortality 24 h post-infection. The melanization observed in the populations herein studied did not indicate refractory since third-stage larvae were observed at the end of the experiment. Most likely, this immune response aimed to control the number of larvae, in order to maintain the equilibrium between vector-parasite. CONCLUSION: The melanization did not seem to be a limiting factor to the development of this filarioid in these local Brazilian Culicidae populations.

Dirofilariasis involving the oral cavity: report of the first case from South America

Oral dirofilariasis is very rare with non-specific clinical manifestations. Here, we report the case of a 65-year-old South American woman with a submucosal nodule on her right buccal mucosa. The nodule was slightly tender and painful. Differential diagnoses included mesenchymal (lipoma or fibrolipoma, solitary fibrous tumor, and neurofibroma) or glandular benign tumors (pleomorphic adenoma) with secondary infections. We performed excisional biopsy. A histopathological examination revealed a dense fibrous capsule and a single female filarial worm showing double uterus appearance, neural plaque, well-developed musculature and intestinal apparatus. Dirofilariasis was diagnosed, and the patient was followed-up for 12 months without recurrence.

Helmintofauna de cães errantes (Canis lupus familiaris) de Cuiabá, Centro-Oeste do Brasil / Helminths parasites of stray dogs (Canis lupus familiaris) from Cuiabá, Midwestern of Brazil

Helminths cause respiratory and gastrointestinal infections in animals, especially in neonates and young animals. Some species of helminth parasites of domestic animals have zoonotic potential, becoming a public health problem, especially when combined with lack of information about the population of these zoonosis and lack of control over of their hosts. This study aimed to identify and quantify the species of helminths from dogs that are not domiciled in the region of Cuiabá, in the Midwest region of Brazil. A total of 100 animals, from the Center for Zoonosis Control of Cuiabá were euthanized and necropsied for helminth searching. Overall 8,217 helminths were found in 85 animals identified in six species: Ancylostoma caninum, Ancylostoma. braziliense, Trichuris vulpis, Toxocara canis, Dirofilaria immitis and Dipylidium caninum. It was evidenced the wide distribution of helminths pathogenic to domestic dogs and especially with zoonotic potential as A. caninum, T. canis, D. caninum and D. immitis. The presence of D. immitis is an important finding, since it is a potentially zoonotic agent, however, this finding is considered sporadic.(AU)

Helmintos causam infecções respiratórias e gastrointestinais em animais, especialmente em neonatos e animais jovens. Algumas espécies de helmintos de animais domésticos possuem potencial zoonótico, se tornando um problema de saúde pública, especialmente quando adicionados a falta de informação da população sobre estas zoonoses e a falta de controle da população de hospedeiros. Este estudo objetivou identificar e quantificar as espécies de helmintos de cães não domiciliados na região de Cuiabá, Centro-Oeste do Brasil. Um total de 100 animais do Centro de Controle de Zoonoses de Cuiabá foram eutanasiados e necropsiados para a procura de helmintos. Ao todo 8.217 helmintos foram encontrados em 85 animais e identificados em seis espécies: Ancylostoma caninum, Ancylostoma. braziliense, Trichuris vulpis, Toxocara canis, Dirofilaria immitis e Dipylidium caninum. Ficou evidente a alta distribuição de helmintos patogênicos para cães e especialmente com potencial zoonótico como A. caninum, T. canis, D. caninum e D. immitis. A presença de D. immitis é um achado importante, considerando o potencial zoonótico do agente, entretanto, o achado é considerado esporádico.(AU)

Helmintofauna de cães errantes (Canis lupus familiaris) de Cuiabá, Centro-Oeste do Brasil / Helminths parasites of stray dogs (Canis lupus familiaris) from Cuiabá, Midwestern of Brazil

Helminths cause respiratory and gastrointestinal infections in animals, especially in neonates and young animals. Some species of helminth parasites of domestic animals have zoonotic potential, becoming a public health problem, especially when combined with lack of information about the population of these zoonosis and lack of control over of their hosts. This study aimed to identify and quantify the species of helminths from dogs that are not domiciled in the region of Cuiabá, in the Midwest region of Brazil. A total of 100 animals, from the Center for Zoonosis Control of Cuiabá were euthanized and necropsied for helminth searching. Overall 8,217 helminths were found in 85 animals identified in six species: Ancylostoma caninum, Ancylostoma. braziliense, Trichuris vulpis, Toxocara canis, Dirofilaria immitis and Dipylidium caninum. It was evidenced the wide distribution of helminths pathogenic to domestic dogs and especially with zoonotic potential as A. caninum, T. canis, D. caninum and D. immitis. The presence of D. immitis is an important finding, since it is a potentially zoonotic agent, however, this finding is considered sporadic.

Helmintos causam infecções respiratórias e gastrointestinais em animais, especialmente em neonatos e animais jovens. Algumas espécies de helmintos de animais domésticos possuem potencial zoonótico, se tornando um problema de saúde pública, especialmente quando adicionados a falta de informação da população sobre estas zoonoses e a falta de controle da população de hospedeiros. Este estudo objetivou identificar e quantificar as espécies de helmintos de cães não domiciliados na região de Cuiabá, Centro-Oeste do Brasil. Um total de 100 animais do Centro de Controle de Zoonoses de Cuiabá foram eutanasiados e necropsiados para a procura de helmintos. Ao todo 8.217 helmintos foram encontrados em 85 animais e identificados em seis espécies: Ancylostoma caninum, Ancylostoma. braziliense, Trichuris vulpis, Toxocara canis, Dirofilaria immitis e Dipylidium caninum. Ficou evidente a alta distribuição de helmintos patogênicos para cães e especialmente com potencial zoonótico como A. caninum, T. canis, D. caninum e D. immitis. A presença de D. immitis é um achado importante, considerando o potencial zoonótico do agente, entretanto, o achado é considerado esporádico.

Dirofilariose humana em Joinville-SC: avaliação clinicopatológica dos primeiros casos relatados na região Sul / Human dirofilariasis in Joinville-SC: clinical-pathological assessment of the first cases reported in the Southern region

INTRODUÇÃO: Dirofilariose é uma zoonose rara causada pelo gênero Dirofilaria e acomete principalmente os pulmões, sendo capaz de simular neoplasia pulmonar. Pouca informação está disponível na literatura sobre a ocorrência e a distribuição de dirofilariose humana na América do Sul. Até 2004, haviam sido descritos apenas 50 casos de dirofilariose humana pulmonar no Brasil, sendo 37 apenas em São Paulo. OBJETIVO: Comprovar a existência de dirofilariose na região de Joinville-SC. MATERIAIS E MÉTODOS: Revisão de arquivos de laboratórios de anatomia patológica da cidade à procura de casos com os termos granuloma parasitário, helminto, helmintíase, verme, Dirofilaria e dirofilariose. Foram incluídos na pesquisa casos que satisfizeram os critérios para dirofilariose, segundo literatura específica. Os prontuários foram revisados e as amostras reprocessadas e analisadas histologicamente por seis colorações diferentes. RESULTADOS: Encontrou-se um caso em globo ocular e sete casos pulmonares, sendo o lobo inferior a localização preferencial (cinco casos). A análise microscópica revelou, nos casos pulmonares, nódulo bem delimitado, frequentemente centrado em uma artéria, com reação granulomatosa e necrose associada à fibrose e infiltrado inflamatório mono e polimorfonuclear, sendo possível identificar segmentos do parasita degenerado, compatível com Dirofilaria immitis. DISCUSSÃO: Todos os parasitas encontrados apresentam características morfológicas idênticas às relatadas na literatura para Dirofilaria immitis. A presença de D. immitis no globo ocular, como observada em um dos pacientes na presente revisão, é rara. CONCLUSÃO: A ocorrência de dirofilariose humana foi confirmada em Joinville e região, sendo causada pela Dirofilaria immitis.

INTRODUCTION: Dirofilariasis is a rare zoonosis caused by Dirofilaria genus, which affects mainly the lungs and may be misdiagnosed as lung cancer. Little information is available regarding the occurrence and distribution of human dirofilariasis in South America. Only 50 cases of human pulmonary dirofilariasis were described in Brazil until 2004, of which 37 were located in São Paulo. OBJECTIVE: To prove the existence of dirofilariasis in Joinville, SC. MATERIAL AND METHODS: The records of anatomic pathology laboratories of the city were reviewed in search for cases with the terms parasitic granuloma, helminth, helminthiasis, worm, Dirofilaria and dirofilariasis. According to specific literature, the cases that met the criteria for dirofilariasis were included in the study. The medical records were reviewed and the samples reprocessed and histologically analyzed by six different stains. RESULTS: We found one ocular case and seven pulmonary cases. The lower lobe was the main location (five cases). In all pulmonary cases, microscopic analysis revealed well defined nodules, frequently centered in a pulmonary artery, with granulomatous reaction and necrosis associated with fibrosis and mono and polymorphonuclear inflammatory infiltrate. It was also possible to identify segments of the deteriorated worm consistent with Dirofilaria immitis. DISCUSSION: All parasites found in this study show morphological characteristics similar to those reported in the literature on Dirofilaria immitis. The presence of D. immitis in the eye, as reported in one of the patients from this review, is rare. CONCLUSION: The occurrence of human dirofilariasis was confirmed in Joinville and region and it was caused by Dirofilaria immitis.

Identificación morfológica y molecular de filarías caninas en una comuna semi-rural de la Región Metropolitana, Chile / Morphological and molecular identification of canine filariae in a semi-rural district of the Metropolitan Region in Chile

Introduction: To date, there has been no definitive confirmation of the presence of zoonotic dirofilariasis in dogs in Chile. Objectives: To study the presence of dirofilarias in blood samples from dogs collected in a semi-rural district near Santiago and to compare their frequency in dogs with and without dermatological manifestations. Methods: We examined 100 blood samples for dog filariae infections using microscopic methods (modified Knott technique). 50 dogs presented dermatological symptoms or signs compatible with filarial infections and 50 were asymptomatic. ITS-2 and 12s rDNA gene amplification by PCR and sequencing were performed in samples microscopically positive for microfilariae. Results. We observed microfilariae in 22 dogs (22%). Of these, 16/50 (32%) were symptomatic and 6/50 (12%) were asymptomatic (p = 0.02). Morphologically, the majority of micro-filariae were similar to Dirofilaria repens, although many had a bigger size than previously described. Nucleotide sequencing of the amplified genes showed no more than 95% homology with the D. repens sequences available for comparison. D. reconditum and D. dracunculoides infections were also identified. Conclusions: These features might indicate the presence of new species of Dirofilaria or a D. repens close related variant in Chile.

Introducción: A la fecha no hay datos concluyentes en Chile respecto a la presencia de dirofilariasis zoonótica en perros. Objetivos: Identificar la presencia de dirofilarias en sangre de perros de una comuna semi-rural cercana a Santiago y comparar su frecuencia en animales con y sin manifestaciones dermatológicas. Materialy Métodos. Se examinó un frotis sanguíneo de 100 perros en busca de microfilarias mediante observación microscópica (técnica de Knott modificada). Cincuenta perros presentaban síntomas o signos dermatológicos que se han asociado a esta parasitosis y 50 eran asintomáticos. Se amplificaron los genes ITS-2 y 12s ADNr de filarías en las muestras con microfilarias al frotis, secuenciando los fragmentos amplificados. Resultados: Se observaron microfilarias en 22 perros (22%), 16/50 (32%) sintomáticos y 6/50 (12%) asintomáticos (p = 0,02). Morfológicamente, la mayoría de las microfilarias observadas fueron similares a D. repens; sin embargo, una gran proporción mostró un tamaño mayor al descrito para esta especie. Las secuencias nucleotídicas de los genes amplificados mostraron una homología no mayor al 95% con las secuencias de D. repens disponibles para comparación. Se identificaron además dos especies poco patógenas, D. reconditum por morfología y secuenciación genética y D. dracunculoides por morfología. Conclusiones: Los resultados indican la existencia de una nueva especie de Dirofilaria cercanamente relacionada a D. repens o de una variante de esta especie.

Diagnóstico de Dirofilaria immitis en el municipio Sucre, estado Sucre, Venezuela / Diagnosis of Dirofilaria immitis in the municipality of Sucre, Sucre state, Venezuela

La dirofilariasis es una patología parasitaria, causada por los nematodos Dirofilaria immitis y D. repens, principalmente. Mientras que D. immitis presenta distribución mundial, D. repens se extiende por el viejo mundo. Ambas especies afectan a caninos y felinos domésticos y salvajes, así como a humanos, por lo que es un problema de salud pública mundial. En este estudio se determinó la prevalencia de D. immitis, en caninos del municipio Sucre, estado Sucre, Venezuela. Se tomaron muestras sanguíneas a 138 caninos domésticos, mayores de seis meses, sin distinción de raza ni sexo, previo consentimiento informado por sus propietarios. El diagnóstico parasitológico de las microfilarias circulantes se realizó por examen directo y método de concentración Knott modificado; las características morfológicas fueron observadas en extendidos teñidos con Giemsa. Se utilizó un estuche comercial, para la captura de antígenos de excreción-secreción de D. immitis. De los 138 caninos estudiados, 12 casos positivos (8,7%) fueron detectados parasitológicamente, mientras que por el estuche comercial se detectaron antígenos en 20 caninos (14,5%), lo que demuestra que existe una dirofilariasis oculta en el 5,8% de los casos evaluados. Uno de los perros microfilarémicos, no presentó antígenos circulantes. La prevalencia de dirofilariasis en el municipio Sucre, estado Sucre fue de 15,2%. Este reporte de dirofilariasis canina en el municipio Sucre, representa un importante aporte en el levantamiento epidemiológico de la enfermedad. Futuros estudios permitirán evaluar el riesgo de infección de las personas que conviven con los perros con dirofilariasis.

Heartworm is a parasitic disease, caused by nematodes Dirofilaria immitis and D. repens, mainly. While D. immitis presents worldwide distribution, D. repens extends the old world. Both species affect canines and felines domestic and wild, as well as human, so it is a global public health problem. In this study we determined the prevalence of D. immitis in dogs in the municipality of Sucre, Sucre state, Venezuela. Blood samples were taken for 138 domestic dogs, over six months, regardless of race or sex, prior informed consent by their owners. The parasitological diagnosis of circulating microfilariae was done by direct examination and concentration method modified Knott, the morphological characteristics were observed in Giemsa-stained smears. We used a commercial kit, for the capture of excretory-secretory antigens of D. immitis. Of the 138 dogs studied, 12 cases (8.7%) were detected parasitologically, whereas the commercial kit antigens were detected in 20 dogs (14.5%), demonstrating that there is an occult infections in 5.8% of the cases. One of the dogs with microfilariae in blood, did not submit antigens circulating. The prevalence of heartworm in the municipality of Sucre, Sucre state was 15.2%. This report of canine heartworm in the municipality of Sucre, represents an important contribution in an epidemiologic survey of the disease. Future studies will assess the risk of infection for people living with dogs with heartworm disease.

Dirofilaria immitis infection in dogs from Maceió, Alagoas, Northeast region of Brazil

De 2.007 amostras de sangue examinadas de cães da cidade de Maceió-AL, foram detectados 62 (3,1%) animais positivos para a presença de microfilárias (mf). Em 11 cães, escolhidos aleatoriamente, foi colhido sangue venoso para a identificação específica de Dirofilaria immitis. Para tal, foram utilizadas a motilidade, o tamanho, a morfologia das mf e a presença de antígenos solúveis do parasito, sendo encontrados cinco animais portadores de D. immitis. Mosquitos da espécie Culex quinquefasciatus foram alimentados com sangue de um cão portador de D. immitis. O desenvolvimento de formas larvárias foi observado nos túbulos de Malpighi, confirmando a ocorrência da dirofilariose canina causada por D. immitis na cidade de Maceió-AL.

Epidemiological aspects of canine dirofilariasis in the metropolitan area of Cuiabá, Mato Grosso: the use of "Immunoblot" and of modified Knott test / Aspectos epidemiológicos da dirofilariose canina no perímetro urbano de Cuiabá, Mato Grosso: emprego do "Immunoblot" e do teste de Knott modificado

The present research focused on studying, through blood and sorology tests, epidemiological aspects of canine dirofilariasis in the metropolitan area of the city of Cuiabá, Brazil. Blood samples from 822 dogs were tested. The research detected, through "Immunoblot" test, antibodies against adult Dirofilaria immitis antigens in 11.81% of the samples, while 0.41% of the dogs presented, through the modified Knott test, microfilariae of D. immitis. The prevalence of canine dirofilariasis in Cuiabá, in the period between June and November 1977, reached 120.8 case per 1,000 dogs. The "Immunoblot" diagnosed as positive 11.27% of the samples previously tested negative when using the modified Knott test. The research statistically analyzed information on the dogs breed, sex, age and region of origin. It also took into account the possibility that the dogs researched might have traveled to endemic regions, might have been given microfilaricides or might be presenting a compatible symptomatology. The environmental characteristics of the dogs dwelling places were also studied. Dogs from one to nine years old, living in the Center-West region of Cuiabá, were statistically found to be the most affected. The majority of them has not been treated with microfilaricide, and has never left the Cuiabá metropolitan area. They lived, however, in neighborhoods close to streams and/or in houses adja

O presente trabalho refere-se a pesquisa dos aspectos epidemiológicos da dirofilariose canina no perímetro urbano de Cuiabá, através de exame de sangue e sorologia. Examinou-se o sangue de 822 cães: em 11,81% das amostras, detectaram-se, por meio de "Immunoblot", anticorpos contra antígenos de Dirofilaria immitis adulto, enquanto em 0,41% foram encontradas, por meio do teste de Knott modificado, microfilárias de D. immitis. A prevalência da dirofilariose canina em Cuiabá, no período de junho a novembro de 1997, e com a metodologia aplicada, foi de 120,8 casos em cada 1.000 animais. O "Immunoblot" diagnosticou como positivas 11,27% das amostras que estavam consideradas negativas pelo teste de Knott modificado. Os autores analisaram estatisticamente informações sobre raça, sexo, idade e região administrativa de origem dos cães pesquisados. Foi questionada a possibilidade de que os animais pesquisados tivessem viajado a regiões endêmicas, usado microfilaricidas, ou apresentado sintomatologia compatível, bem como estudadas as características ecológicas do local de moradia. Cães com idade variando entre um e nove anos e residentes na região Centro-Oeste apresentaram maior índice de positividade. A maioria não apresentava sintomatologia compatível com a doença, não tinha história clínica do uso de microfilaricidas e/ou preventivos contra dirofilariose canina e nunca havia saído do pe

Diagnosis of canine dirofilariasis, by ELISA test, in the State of São Paulo / Diagnóstico de dirofilariose oculta pelo teste de ELISA, em cães do Estado de São Paulo

The occult dirofilariasis is considered a great diagnostic problem and may be related to: a) pre-patent infections; b) infections caused by worms of one only sex; c) parasites sterility due to the age or induced by drugs action; d) iirmune mediate response. The present study estimated the prevalence of the dirofilariasis in dogs in São Paulo State by means R TM of the ELISA test (CITER Semi-Quant TM Canine Heartworm Antigen Test Kit) as well as it tried to caracterize the cause of the circulating microfilaraemia absence using subsidiary exams. From 244 examined sera, 35 (14.34%) showed to be positive. From these, 20 presented one or more alternations (radiographic/ haematologic/eletrocardiographic), besides the positive ELISA test, which were compatible with dirofilariasis diagnosis. In the 15 animals left, which were assintomatic and seropositive by means of the ELISA test, no pre-patent infection was possible in spite of being to the infection risk for 6 months. Also the parasite sterility in consequence to drugs action was no observed

A dirofilariose oculta constitui-se num grande problema diagnóstico e pode estar relacionada a: a) infecções pré-patentes; b) infecções causadas por vermes de um único sexo; c) esterilidade dos parasitas devido à idade ou induzida por ação de drogas; d) resposta imune mediada. Avaliou-se, no presente trabalho, a prevalência de dirofilariose em cães do Estado de São Paulo, através do teste de ELISA (CITER Semi-Quant TM Canine Heartworm Antigen Test Kit), bem  como se tentou caracterizar a causa da ausência de microfilaremia circulante, com auxílio de exames subsidiários. De 244 soros examinados, 35 (14,34%) mostraram-se positivos. Destes, 20 apresentaram, além do teste de ELISA positivo, una ou mais alterações (radiográficas /eletrocardiográficas), compatíveis com o diagnóstico de dirofilariose canina; e, nos demais 15 animais, assintomáticos, também soropositivos pelo teste de ELISA, descartou-se a forma de infecção prépatente, pois haviam sido expostos ao risco da infecção há mais de 6 meses, e também a esterilidade dos parasitas conseqüentemente à ação de drogas.

Dirofilaria immitis in the peritoneal cavity of a dog (São Paulo, Brazil): clinical features / Dirofilaria immitis na cavidade peritoneal, de cão: aspectos clínicos

An adult, male specimen from class Nematoda, superfamily Filaroidea, family Filaridae, species Dirofilaria immitis in the peritoneal cavity of a bitch, proceeding from São Sebastião, notrh costland of São Paulo State is described. The paciente presented ascitis, resulting from the right cardiac failure. When it was submitted to an abdominal paracenthesis, a parasite came out together the modified transudate, cumulated in peritoneal cavity. The results of the clinicopathological tests, electrocardiogram and radiographic examination are discussed.

Descreve-se o achado de exemplar adulto, macho da classe Nematoda, superfamilia Filaroidea, familia Filaridae, espécie Dirofilaria immitis, localizado na cavidade peritoneal de uma cadela provinda da cidade de São Sebastião, no litoral norte do estado de São Paulo. O animal apresentava ascite, decorrente de insuficiência cardíaca congestiva direita. Quando submetida a paracentese abdominal deparou-se com a saída do verme, no transudato modificado coletado na cavidade peritoneal da fêmea canina. Discutem -se os resultados dos exames laboratoriais, da pesquisa de microfilarias, dos exames eletrocárdio e radiográficos.