This study was carried out to determine the usefulness of standard electrocardiography for the diagnosis of early canine heartworm disease. Baseline electrocardiograms were recorded in 12 dogs. Thirty artificial Dirofilaria immitis worms were inserted in the pulmonary artery of each dog. New electrocardiograms were recorded on days 1-4, 7, 14, 21, 28 and 35 after insertion of worms. A significant attenuation of amplitude of Q wave in lead I was recorded on days 1-4, 7, 14, 21, 28 and 35; of R wave in lead II on days 21, 28 and 35; and of S wave in lead aVR on days 7, 14, 21, 28 and 35. Duration of the QRS complex in lead AVF was significantly prolonged on day 14. In 41.6% of the dogs, right axis deviation was recorded. These results suggest that for a dog whose normal baseline standard electrocardiogram is known, a comparison of the QRS complex of the baseline with those of subsequent standard electrocardiograms may suggest early canine heartworm disease when there is an attenuation of amplitude of Q wave in lead I, R wave in lead II and S wave in lead aVR. An additional indication can be right axis deviation.

Dirofilaria immitis, commonly known as dog heartworm, is a dangerous filarial nematode that is transmitted by a mosquito vector. Although this parasite is historically localized to regions closer to the equator, the last few decades have experienced an increase in the amount of dog heartworm cases in Northern California, most notably in Lake and San Joaquin Counties. The primary vector of D. immitis in Northern California is Aedes sierrensis, but it is not prevalent enough in some counties to explain the increase in infections. Because of this, more prevalent and abundant species should be assessed for their ability to transmit heartworm. Culex pipiens complex (wild) and Culiseta incidens (laboratory-raised colonies) were chosen as potential vectors during this study due to their ability to meet several key vector criteria, their relative abundance in the areas of interest, and the fact that they habitually take bloodmeals from domestic dogs. Additionally, Ae. sierrensis colonies were used in this study, based on previous knowledge that they are highly competent vectors. Female mosquitoes were infected with 2.5, 5, or 10 mff/ul of D. immitis-infected blood, and decapitated at 15, 18, and 21 days post-infection. Mosquitoes were subsequently tested via qPCR for the presence and relative quantification of D. immitis DNA. We found that Ae. sierrensis and Cx. pipiens complex were both able to support the development of D. immitis to its infective stage, while Cs. incidens was not a competent vector. We also concluded that including a standard curve of known amounts of D. immitis larvae makes it possible to approximate the intensity of the infection in the mosquito. The identification of these important vectors, and the ability to assess infection intensity, may be helpful in the continued vector control efforts in Northern California and beyond.

BACKGROUND:This paper examines the individual factors that influence prevalence rates of canine heartworm in the contiguous United States. A data set provided by the Companion Animal Parasite Council, which contains county-by-county results of over nine million heartworm tests conducted during 2011 and 2012, is analyzed for predictive structure. The goal is to identify the factors that are important in predicting high canine heartworm prevalence rates.METHODS:The factors considered in this study are those envisioned to impact whether a dog is likely to have heartworm. The factors include climate conditions (annual temperature, precipitation, and relative humidity), socio-economic conditions (population density, household income), local topography (surface water and forestation coverage, elevation), and vector presence (several mosquito species). A baseline heartworm prevalence map is constructed using estimated proportions of positive tests in each county of the United States. A smoothing algorithm is employed to remove localized small-scale variation and highlight large-scale structures of the prevalence rates. Logistic regression is used to identify significant factors for predicting heartworm prevalence.RESULTS:All of the examined factors have power in predicting heartworm prevalence, including median household income, annual temperature, county elevation, and presence of the mosquitoes Aedes trivittatus, Aedes sierrensis and Culex quinquefasciatus. Interactions among factors also exist.CONCLUSIONS:The factors identified are significant in predicting heartworm prevalence. The factor list is likely incomplete due to data deficiencies. For example, coyotes and feral dogs are known reservoirs of heartworm infection. Unfortunately, no complete data of their populations were available. The regression model considered is currently being explored to forecast future values of heartworm prevalence.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-06-15T12:42:03Z No. of bitstreams: 1 Lorena Adao Vescovi Sellos Costa.pdf: 1088156 bytes, checksum: b47a8ec22863f3dbd59c57bb1699875b (MD5) / Made available in DSpace on 2016-06-15T12:42:03Z (GMT). No. of bitstreams: 1 Lorena Adao Vescovi Sellos Costa.pdf: 1088156 bytes, checksum: b47a8ec22863f3dbd59c57bb1699875b (MD5) Previous issue date: 2016-02-04 / The main clinical signs of heartworm disease in dogs are characterized by respiratory manifestations which are associated to signs such as dry cough, exercise intolerance, tachypnea, hemoptysis and dyspnea. Although, the radiographic examination of thorax has been used to identify changes in the pulmonary patterns, the Computed Tomography (CT) has been currently considered the method of choice for evaluation of pulmonary parenchyma and lower airways. Therefore, the aim of this study was to assess pulmonary changes in dogs naturally infected by Dirofilaria immitis by using CT. Domiciled dogs (n = 12) living in the Metropolitan Region of Recife were used in this study. All animals positive for D. immitis were physically examined, and analyzed through the microscopic examination of blood samples, serological analysis (D. immitis and Leishmania infantum), electrocardiography and CT. The quantitative assessment of pulmonary radiodensity presented mean value of -628.58 ± 56.60 HU, which was significantly higher than the normal parameter of lung parenchyma of dogs. Moreover, the results revealed the presence of interstitial infiltrate, increase of tortuosity of caudal arteries, increase of bronchial arteries and gap filling of pulmonary artery were present in different degrees, including in the animals that present occult heartworm. Afterwards, a female Dachshund with eight-year-old was treated with Ivermectin and Doxycycline, being monitored twice by CT. The CT examination performed before the treatment showed the presence of D. immitis adults in the pulmonary artery, vascular tortuosity and parenchymal inflammation. After therapy, it was observed an improvement in the clinical status of the animal, which scored negative at serological examination. In addition, it was observed the remission of pulmonary changes and absence of D. immitis adults in blood vessels and heart chambers. In conclusion, the CT may be considered an important tool to detect changes in pulmonary parenchyma of dogs naturally infected by D. immitis, in addition, it allows the diagnosis of occult heartworm. / As principais manifestações clínicas da dirofilariose em cães são respiratórias e causam prejuízo à função pulmonar, que se encontra associada a sinais clínicos de tosse seca, intolerância ao exercício, taquipneia, hemoptise e dispneia. Apesar do estudo radiográfico de tórax permitir a identificação da alteração de padrões pulmonares da doença, a tomografia computadorizada (TC) tem sido considerada o exame de eleição para avaliação do parênquima pulmonar e vias aéreas inferiores. Sendo assim, o objetivo deste trabalho foi avaliar por meio da TC as alterações pulmonares de cães infectados naturalmente por Dirofilaria immitis. Para tanto, inicialmente foram selecionados 12 cães com diagnósticos positivos para dirofilariose, domiciliados na região metropolitana do Recife, Pernambuco, Brasil, os quais foram submetidos ao exame clínico, pesquisa de microfilaria circulante, exame sorológico, pesquisa de anticorpos IgG anti- Leishmania infantum, eletrocardiográfico e TC pulmonar apresentou valores médios de -628,58 ± 56,60 HU, apresentando-se significativamente maior quando comparado com os valores do parênquima pulmonar para cães hígidos. Os resultados revelaram que a presença de infiltrado intersticial periarterial, aumento e tortuosidade das artérias pulmonares caudais, aumento da relação arteriobronquial e falhas de contraste iodado nas artérias pulmonares foram presentes em graus variáveis, inclusive nos cães com dirofilariose oculta. Posteriormente, um desses animais, uma cadela de oito anos de idade, da raça Dachshund foi submetida ao tratamento com ivermectina e doxiciclina, sendo monitorada em dois momentos pela TC. Dentre os achados no exame tomográfico pré-tratamento, destacam-se sinais tromboembolismo vascular sugerindo a presença de D. immitis em artéria pulmonar, tortuosidade vascular e processo inflamatório parenquimatoso. Após a terapia estabelecida o animal apresentou pesquisa de antígeno circulante negativa, além da remissão dos achados pulmonares, ausência de imagens sugestivas de D. immitis em vasos e câmaras cardíacas, e melhora clínica significativa. Conclui-se que a TC pode ser utilizada como ferramenta no estadiamento das alterações causadas pela infecção por D. immitis em cães, monitorar a terapia, além de permitir o diagnóstico da dirofilariose oculta.

Submitted by (edna.saturno@ufrpe.br) on 2016-10-19T17:36:44Z No. of bitstreams: 1 Marco Antonio Granja Barbosa.pdf: 251854 bytes, checksum: 0a11e9c0c9eb675917e79b17a0de1714 (MD5) / Made available in DSpace on 2016-10-19T17:36:44Z (GMT). No. of bitstreams: 1 Marco Antonio Granja Barbosa.pdf: 251854 bytes, checksum: 0a11e9c0c9eb675917e79b17a0de1714 (MD5) Previous issue date: 2004-02-07 / Studies were performed in two groups of mixed-breed male dogs containing six (Experimental Group) and two (Control Group) animals which were administered IV a crude, whole-body extract of female heartworms or saline solution respectively. The frequency of clinical signs and shock-like reaction as well as changes in clinical parameters such as electrocardiographic record, RBC and WBC counts, serum alanine amino transferase, aspartate amino transferase, creatine phosphokinase and also urea were monitored. The results had been analyzed by the test of Wilcoxon e Mann-Whitney for Clinical hematological, clinical chemistry and by the test of Fischer to electrocardiographic values respectively. Shock with clinical signs such as the pale color of the visible mucous membranes, respiratory disorders, developed in all crude, whole-body extract inoculated dogs. It was observed a significative difference not only between the lynfocytes count and CPK values but also with RBC and eosinophil count absolute. These results indicated that some products present on whole-body extract of female heartworms might be responsible for the onset of shock in dogs. / Foram realizados estudos em dois grupos de caninos,machos, sem raça definida, sendo um grupo experimental composto de seis animais e dois animais no grupo controle, os quais foram inoculados com extrato bruto de fêmeas de Dirofilaria immitis e solução salina respectivamente, com objetivo de avaliar as alterações clínicas, hematológicas e bioquímico séricas. A freqüência dos sinais clínicos apresentados durante o choque foram monitoradas, assim como as modificações nos parâmetros eletrocardiográficos, hematológicos, bioquímico séricos no período compreendido entre cinco minutos a 24 horas após o inicio do experimento. Os resultados foram analisados através dos testes de Wilcoxon e Mann-Witney para as alterações clínicas, hematológicas e bioquímicas, e o teste de Fischer para os valores do eletrocardiograma. Sinais clínicos compatíveis com choque como palidez das membranas mucosas visíveis e distúrbios respiratórios, foram observados em todos os animais inoculados com extrato bruto de Dirofilaria immitis. Diferença significativa foi observada não apenas entre a contagem de linfócitos e os valores de CK, mas também na contagem total de hemácias e na contagem absoluta de eosinófilos.Os resultados indicam que substâncias presentes nos nematóides fêmeas foram responsáveis pelo aparecimento de choque.

A dirofilariose canina é uma parasitose de distribuição mundial cujo agente etiológico é um verme nemátoda filarióide. Em sua fase adulta, os vermes produzem microfilárias por meio de reprodução sexuada. Sua transmissão ocorre por meio de mosquitos que atuam como hospedeiros intermediários. No Brasil, até o momento, a dirofilariose canina foi encontrada em 15 estados de todas as regiões. A maioria dos estudos está concentrada nas regiões sudeste e sul. A prevalência nacional é de 2%, embora alguns trabalhos tenham encontrado prevalências locais mais elevadas. Neste trabalho apresentamos o primeiro registro de dirofilariose canina para o estado de Rondônia com mapas de distribuição dos cães positivos e análise de mosquitos. Amostras de sangue de 727 cães foram coletadas aleatoriamente na cidade de Porto Velho. As amostras forma analisadas em busca de microfilárias e antígenos circulantes usando duas técnicas: microscopia ótica de gota espessa corada com Giemsa e imunocromatografia de fluxo lateral (ICT). As amostras positivas foram também testadas por PCR, as negativas forma testadas na mesma técnica em pools. Mosquitos foram coletados no domicilio e peridomicílio de todos os casos de cães positivos, estes mosquitos foram testado por PCR em busca de DNA de Dirofilaria immitis. Um mapa de distribuição dos casos de cães positivos foi elaborado. Noventa e três amostras de sangue foram positivas no ICT, representando 12,8% da amostra total, nenhuma amostra foi positiva na gota espessa. O PCR das amostras de sangue resultou em 10% para as positivas no ICT e 0% nas negativas no mesmo teste. Entre os 93 cães positivos, 89 (95,7%) nasceram em Porto Velho. Nenhuma diferença estatística foi observada entre cães que moram em quintais ou intradomicílio. O mapa de distribuição indica um hotspot na região norte da cidade. O PCR dos mosquitos resultou em apenas um pool positivo. A transmissão de dirofilariose canina ocorre na cidade de Porto velho e a frequência que ocorre nos cães é considerada moderada. A técnica de imunocromatografia e PCR são mais eficazes na detecção de dirofilariose comparadas a gota espessa. A confirmação de transmissão de dirofilariose canina em Porto Velho, coloca esta doença no ranking de diagnóstico diferencial de nódulos pulmonares em Porto Velho. / Heartworm is an infectious disease with worldwide distribution. Mosquitoes acts as intermediary host and vectors. In Brazil, until now, heatworm was found in 15 states with an national average of 2%. This present work aims to report for the first time canine heartworm in the state of Rondônia and confirms the transmission of the disease in the state. Blood samples were randomly collected from 727 dogs in the municipality of Porto Velho. The samples were analyzed for the presence of microfilariae and circulating antigens using two different techniques: thick blood microscopy stained with Giemsa and immunochormatography for the detection of filarial antigens. Aiming to test the efficacy of the immunoassay test, all the positive cases were examined by PCR and pools of negative samples were also examined. Mosquitoes were collected at the domiciles presenting positive cases and analyzed by PCR. A distribution map was made with positive cases. Ninety three blood samples out of 727 (12.8%) were positive by the immunoassay technique and none by the thick smear method. All the positive cases by the immunoassay technique were examined by PCR and pools of all negatives samples were also examined resulting in 10% and 0% positivity frequency, respectively. Among the 93 positive dogs, 89 (95.7%) were born in Porto Velho. No differences in the frequency of infection were observed between dogs raised indoor or in the yards. The distribution map indicates a hotspot in the north area of the city. Mosquitoes were analyzed by PCR, resulting in only one positive pool. This result shows that the transmission of canine heartworm is occurring in the municipality of Porto Velho and has moderate prevalence among dogs. The immunoassay technique and the PCR method are more efficient in detecting D. immitis infections in dogs when compared to the blood smear technique. The confirmation of heartworm transmission in Porto Velho also includes this disease among the ranks of differential diagnosis of pulmonary nodules in humans in Rondônia.

A dirofilariose canina é uma parasitose de distribuição mundial cujo agente etiológico é um verme nemátoda filarióide. Em sua fase adulta, os vermes produzem microfilárias por meio de reprodução sexuada. Sua transmissão ocorre por meio de mosquitos que atuam como hospedeiros intermediários. No Brasil, até o momento, a dirofilariose canina foi encontrada em 15 estados de todas as regiões. A maioria dos estudos está concentrada nas regiões sudeste e sul. A prevalência nacional é de 2%, embora alguns trabalhos tenham encontrado prevalências locais mais elevadas. Neste trabalho apresentamos o primeiro registro de dirofilariose canina para o estado de Rondônia com mapas de distribuição dos cães positivos e análise de mosquitos. Amostras de sangue de 727 cães foram coletadas aleatoriamente na cidade de Porto Velho. As amostras forma analisadas em busca de microfilárias e antígenos circulantes usando duas técnicas: microscopia ótica de gota espessa corada com Giemsa e imunocromatografia de fluxo lateral (ICT). As amostras positivas foram também testadas por PCR, as negativas forma testadas na mesma técnica em pools. Mosquitos foram coletados no domicilio e peridomicílio de todos os casos de cães positivos, estes mosquitos foram testado por PCR em busca de DNA de Dirofilaria immitis. Um mapa de distribuição dos casos de cães positivos foi elaborado. Noventa e três amostras de sangue foram positivas no ICT, representando 12,8% da amostra total, nenhuma amostra foi positiva na gota espessa. O PCR das amostras de sangue resultou em 10% para as positivas no ICT e 0% nas negativas no mesmo teste. Entre os 93 cães positivos, 89 (95,7%) nasceram em Porto Velho. Nenhuma diferença estatística foi observada entre cães que moram em quintais ou intradomicílio. O mapa de distribuição indica um hotspot na região norte da cidade. O PCR dos mosquitos resultou em apenas um pool positivo. A transmissão de dirofilariose canina ocorre na cidade de Porto velho e a frequência que ocorre nos cães é considerada moderada. A técnica de imunocromatografia e PCR são mais eficazes na detecção de dirofilariose comparadas a gota espessa. A confirmação de transmissão de dirofilariose canina em Porto Velho, coloca esta doença no ranking de diagnóstico diferencial de nódulos pulmonares em Porto Velho. / Heartworm is an infectious disease with worldwide distribution. Mosquitoes acts as intermediary host and vectors. In Brazil, until now, heatworm was found in 15 states with an national average of 2%. This present work aims to report for the first time canine heartworm in the state of Rondônia and confirms the transmission of the disease in the state. Blood samples were randomly collected from 727 dogs in the municipality of Porto Velho. The samples were analyzed for the presence of microfilariae and circulating antigens using two different techniques: thick blood microscopy stained with Giemsa and immunochormatography for the detection of filarial antigens. Aiming to test the efficacy of the immunoassay test, all the positive cases were examined by PCR and pools of negative samples were also examined. Mosquitoes were collected at the domiciles presenting positive cases and analyzed by PCR. A distribution map was made with positive cases. Ninety three blood samples out of 727 (12.8%) were positive by the immunoassay technique and none by the thick smear method. All the positive cases by the immunoassay technique were examined by PCR and pools of all negatives samples were also examined resulting in 10% and 0% positivity frequency, respectively. Among the 93 positive dogs, 89 (95.7%) were born in Porto Velho. No differences in the frequency of infection were observed between dogs raised indoor or in the yards. The distribution map indicates a hotspot in the north area of the city. Mosquitoes were analyzed by PCR, resulting in only one positive pool. This result shows that the transmission of canine heartworm is occurring in the municipality of Porto Velho and has moderate prevalence among dogs. The immunoassay technique and the PCR method are more efficient in detecting D. immitis infections in dogs when compared to the blood smear technique. The confirmation of heartworm transmission in Porto Velho also includes this disease among the ranks of differential diagnosis of pulmonary nodules in humans in Rondônia.

Dirofilaria immitis Leidy (dog heartworm) is a life-threatening parasite transmitted by mosquitoes to domestic dogs. Endemic in the eastern United States, cases have become more prevalent over the last few decades. While prevalence in California is generally low, Lake and San Joaquin Counties have reported rates comparable to the East Coast at 3.73% and 0.71%(CAPC 2017), respectively. Aedes sierrensis is thought to be responsible for transmission in California, but in some cases, it exists in inadequate quantities and temporal ranges to explain parasite activity. Based on Huang et al. (2013) and Tran (2016), bloodfeeding patterns, and other vector criteria, Culex pipiens complex and Culiseta incidens were chosen to evaluate for vector competence. Female field-caught mosquitoes were reared, infected (2.5-5 mff/μl), and decapitated at 15, 18, or 21 days post infection (dpi). Cs. incidens was reluctant to feed using an artificial feeding system and will require additional trials. On the contrary, trials on Ae. sierrensis and Cx. pipiens complex were both completed successfully. Both species were determined to be competent vectors of D. immitis. Based on our findings, more than half of Ae. sierrensis females produced emerging L3s by 21 dpi, while Cx. pipiens complex never produced L3s in more than 5% of females. In conjunction with other factors such as the detection of D. immitis in wild mosquitoes, host-seeking preferences for domestic dogs, and appropriate temporal overlap, this suggests that both Ae. sierrensis and Cx. pipiens complex may play central roles in Lake or San Joaquin Counties, CA when abundant. Targeted control efforts are necessary to reduce the incidence of canine heartworm in these areas. While Lake and San Joaquin Counties, CA were the focus of this study, our results may be applicable to the western United States when these species are relevant.