Vectorial competence of Aedes aegypti (Linnaeus 1762) Rio de Janeiro Strain, to Dirofilaria immitis (Leidy 1856)

Dirofilaria immitis (Leidy 1856), a nematode parasite, is the etiologic agent of canine heartworm disease and mosquitoes are essential intermediate hosts. Mosquito susceptibility to the worms differ with species, strains and also among individuals of the same strain. To evaluate the degree of susceptibility of Rio de Janeiro laboratory raised strain of Aedes aegypti, we fed mosquitoes on canine blood with different densities of microfilariae (mf). There was no significant difference in the rate of development among the three different densities of mf. Infective larvae were found in the head and proboscis of all mosquitoes provided bloodmeals with different densities of mf after the 11th day post-infection. The infection rate of mosquitoes after ingestion of blood containing 3,000 mf/ml, 5,000 mf/ml and 7,000 mf/ml were 55.3%, 66.7% and 100%, respectively. The vector efficiency indices ranged from 1.6 to 9.3. The finding of L3 stage larvae, high infection rates and vector efficiency indices suggest that Ae. aegypti, Rio de Janeiro laboratory strain, is a potential vector of D. immitis, although of low efficiency.

Leishmaniaasi ja sydänmatotauti tuontikoiralla : tapausselostus

Summary: Leishmaniasis and heartworm disease in an imported dog

Endothelium-dependent and -independent hepatic artery vasodilatation is not impaired in a canine model of liver ischemia-reperfusion injury

We investigated whether hepatic artery endothelium may be the earliest site of injury consequent to liver ischemia and reperfusion. Twenty-four heartworm-free mongrel dogs of either sex exposed to liver ischemia/reperfusion in vivo were randomized into four experimental groups (N = 6): a) control, sham-operated dogs, b) dogs subjected to 60 min of ischemia, c) dogs subjected to 30 min of ischemia and 60 min of reperfusion, and d) animals subjected to 45 min of ischemia and 120 min of reperfusion. The nitric oxide endothelium-dependent relaxation of hepatic artery rings contracted with prostaglandin F2a and exposed to increasing concentrations of acetylcholine, calcium ionophore A23187, sodium fluoride, phospholipase-C, poly-L-arginine, isoproterenol, and sodium nitroprusside was evaluated in organ-chamber experiments. Lipid peroxidation was estimated by malondialdehyde activity in liver tissue samples and by blood lactic dehydrogenase (LDH), serum aspartate aminotransferase (AST) and serum alanine aminotransferase (ALT) activities. No changes were observed in hepatic artery relaxation for any agonist tested. The group subjected to 45 min of ischemia and 120 min of reperfusion presented marked increases of serum aminotransferases (ALT = 2989 ± 1056 U/L and AST = 1268 ± 371 U/L; P < 0.01), LDH = 2887 ± 1213 IU/L; P < 0.01) and malondialdehyde in liver samples (0.360 ± 0.020 nmol/mgPT; P < 0.05). Under the experimental conditions utilized, no abnormal changes in hepatic arterial vasoreactivity were observed: endothelium-dependent and independent hepatic artery vasodilation were not impaired in this canine model of ischemia/reperfusion injury. In contrast to other vital organs and in the ischemia/reperfusion injury environment, dysfunction of the main artery endothelium is not the first site of reperfusion injury.

Contribuição para o estudo da prevalência de Dirofilariose Felina na Sub-Região do Baixo Vouga

A Dirofilariose é uma doença parasitária, provocada por um nemátode, Dirofilaria immitis que, não obstante ser considerada rotineiramente como diagnóstico diferencial em canídeos, é bastante subdiagnosticada em felinos. Nestes, a infecção caracteriza-se por uma baixa carga parasitária e microfilarémia rara ou transitória, tornando o diagnóstico num desafio clínico, não só pela sintomatologia inespecífica, como pelas limitações dos meios de diagnóstico. Por exemplo, em Portugal ainda não é comercializado o teste de detecção de anticorpos contra D. immitis. O objectivo deste estudo foi estimar a prevalência de D. immitis em felinos por pesquisa de antigénios, na sub-região do Baixo Vouga, recorrendo ao teste SNAP® Feline Triple® Test (Idexx). Para o efeito foi colhida uma amostra de setenta e dois gatos, sintomáticos e assintomáticos. Esta zona possui uma prevalência de Dirofilariose em cães assintomáticos de 9,3%. Nenhum dos animais testados apresentou microfilarémia no teste de gota fresca. A detecção sérica de antigénios de D. immitis foi de 1,4%, resultado que poderá alertar a comunidade veterinária para o risco de gatos manifestarem esta doença, bem como o dever de implementar uma correcta profilaxia, sobretudo por se tratar de uma doença severa e mortal para os felídeos e pelos riscos que representa para a Saúde Pública, uma vez que se trata de uma zoonose.

Susceptibility of mosquito vectors to Dirofilaria immitis on Madeira Island, Portugal

Dirofilaria immitis (Leidy, 1856), an agent of heartworm disease, is an important parasite from both the veterinary standpoint and as a model to study human filariasis. It is a mosquito-borne filarial nematode which inhabits the right ventricle and pulmonary arteries of dogs. D. immitis is an important disease agent on Madeira Island with about 30% of dogs testing positive for this worm. Nevertheless, the vectors of this parasite in Madeira have never been studied, nor has the interaction between pathogen and vector, or the environmental variables that might influence heartworm transmission. Innate susceptibility to infection is only one component of vector competence, and field isolation of naturally infected mosquitoes has shown the capability of D. immitis to exploit a great diversity of vector species under natural conditions. The purpose of this work was to determine which mosquitoes are vectors of heartworm disease, the relation between population density and environment, and the association between immune response of the vector to the filarial parasite. Seasonal abundance of Culex theileri and Culex pipiens molestus was studied. Correlation and canonical correspondence analysis were performed using abundance data of these two species with selected weather variables, including mean temperature, relative humidity and accumulated precipitation. The most important factor determining Cx. theileri abundance was accumulated precipitation, while Cx. pipiens molestus abundance did not have any relationship with weather variables. Field studies were performed to verify whether Cx. theileri Theobald functions as a natural vector of D. immitis on Madeira Island, Portugal. Cx. theileri tested positive for D. immitis for the first time. The same study was made regarding Cx. p. molestus. Two abnormal L2 stage filarial worms were found in Malpighian tubules in field caught Cx. p. molestus. In the laboratory, two strains of Cx. p. molestus were studied for their susceptibility to D. immitis. None presented infective-stage larvae. Finally, because Cx. p. molestus is an autogenous mosquito, we evaluated the reproductive costs when this mosquito mounts an immune response against D. immitis in the absence of a blood meal. This mosquito showed an active immune response when inoculated intrathoracically with microfilariae (mf) of the heartworm. The ovaries from mosquitoes undergoing melanotic encapsulation developed more eggs than those which could not melanize the mf. This fact is contradictory with some previous studies of reproductive costs in Armigeres subalbatus and Ochlerotatus trivittatus, and it was the first time that an autogenous mosquito was used to study this subject.

Dirofilariose: zoonose emergente negligenciada

A dirofilariose é uma zoonose pouco conhecida causada por Dirofilaria spp., nematódeo mais conhecido como verme do coração dos cães (Dirofilaria immitis), parasita do sistema circulatório desses animais, mas que também pode acometer gatos e o ser humano. Sua ocorrência está intimamente ligada à presença de mosquitos vetores (Aedes spp., Anopheles spp., Culex spp.), condições climáticas favoráveis, assim como trânsito entre regiões indenes e endêmicas/epidêmicas. O ser humano pode se infectar com D. immitis (pulmão), Dirofilaria repens (pulmão, subcutâneo) e Dirofilaria tenuis (subcutâneo). A fisiopatologia está intimamente ligada à morte do parasita onde, no cão, pode induzir a obstrução de vasos circulatórios e no ser humano produzir uma lesão nodular com intensa reação inflamatória no parênquima pulmonar com formato de moeda observada nas radiografias. Pode ser diagnosticada pelo exame físico, pela detecção de microfilárias na circulação sangüínea, imunoadsorção enzimático (ELISA), alterações radiográficas, ecocardiografia, ultrassonografia e necropsia. Há riscos no tratamento, sendo a prevenção com a utilização de drogas nos animais o método mais eficaz, principalmente em visitas a áreas endêmicas ou epidêmicas, diminuindo-se, assim, o risco para saúde pública devido à disseminação do parasita.

Infection in domestic dogs (Canis lupus familiaris, Linnaeus, 1758) from Guaratuba, Parana, Brazil by circulating microfilariae of Acanthocheilonema reconditum (Grassi, 1889)

The epidemiologic frameworks of zoonosis periodically change in some of its aspects, involving the emergence or reemergence of men and animals' worsening of health. In this scenario, in which rapid changes can happen, the analysis of the prevalence of diseases, as the filariasis diagnosed in dogs from the coastline of Parana, has significant relevance. This study has been carried out with 422 dogs and aimed to determine the prevalence of circulating microfilariae of Acanthocheilonema reconditum, both in animals accommodated at the municipal kennels, as those that live in the district COHAPAR II, both places located in the metropolitan area of the city of Guaratuba-Parana, through two blood tests: evaluation of fresh blood, by the technique of the 'thick drop' and method of Knott modified by Newton and Wright. Thirty of the evaluated animals (7.10%), twenty two males and eight females, showed the presence of microfilariae of A. reconditum as result.

Estudio de biomarcadores de daño cardiopulmonar en la dirofilariosis canina por Dirofilaria immitis

Programa de doctorado: Clínica e investigación terapéutica.

Evaluación de las proteínas de fase aguda en perros infectados por "Dirofilaria immitis"

Programa de doctorado: Clínica e investigación terapéutica

Neurologic complications after melarsomine dihydrochloride treatment for Dirofilaria immitis in three dogs.

Melarsomine dihydrochloride is highly effective against both sexes of adult and L5 Dirofilaria immitis. Common adverse reactions include injection site irritation and reluctance to move. Neurologic complications associated with i.m. injection of melarsomine dihydrochloride for treatment of heartworm disease in 3 dogs are described. Different degrees of neurologic complications have been identified; the pathophysiologic features are unknown. It is speculated that the compound migrates out of the injection site via fascial planes and causes an ascending inflammation along nerve roots. The resulting extradural cord compression secondary to extensive inflammation and necrosis of epidural fat could induce a variety of neurologic deficits. Alternatively, inappropriate injection technique may result in direct contact of melarsomine with neural tissue. A heightened awareness of proper injection technique might prevent the development of most neurologic complications.

Population structure of the peridomestic mosquito Ochlerotatus notoscriptus in Australia

Ochlerotatus notoscriptus (Skuse) (Diptera: Culicidae) is the predominant peridomestic mosquito in Australia where it is the primary vector of dog heartworm, Dirofilaria immitis (Leidy), and a potentially important vector of arboviruses (Barmah Forest, Ross River) with geographical variation of vector competence. Although widespread, Oc. notoscriptus has low dispersal ability, so it may have isolated subpopulations. The identification of gene flow barriers may assist in understanding arbovirus epidemiology and disease risk, and for developing control strategies for this species. We investigated the population structure of Oc. notoscriptus from 17 sites around Australia, using up to 31 putative allozyme loci, 11 of which were polymorphic. We investigated the effect of larval environment and adult morphology on genetic variation. At least five subpopulations were found, four in New South Wales (NSW) and one unique to Darwin. Perth samples appear to be a product of recent colonization from the Australian east coast. For NSW sites, a Mantel test revealed an isolation by distance effect and spatial autocorrelation analysis revealed an area of effective gene flow of 67 km, which is high given the limited dispersal ability of this species. No consistent difference was observed between 'urban' and 'sylvan' habitats, which suggests frequent movement between these sites. However, a finer-scaled habitat study at Darwin revealed small but significant allele frequency differences, including for Gpi. No fixed allozyme differences were detected for sex, size, integument colour or the colour of species-diagnostic pale scales on the scutum. The domestic habit of Oc. notoscriptus and assisted dispersal have helped to homogenize this species geographically but population structure is still detectable on several levels associated with geographical variation of vector competence.

Relatório de estágio em clínica e cirurgia de animais de companhia

O estágio curricular a que se refere o presente relatório foi realizado no Hospital Veterinário do Baixo Alentejo, em Beja, entre 15/09/2014 e 15/03/2015, sob orientação do Dr. André Cláudio. Na primeira parte é apresentada a casuística acompanhada durante o estágio e a segunda parte consiste numa monografia referente ao tema “Dirofilariose canina”, onde é apresentada uma revisão bibliográfica seguida de um caso clínico. A dirofilariose canina é uma doença endémica em Portugal causada por nemátodes do género Dirofilaria, que têm como hospedeiros definitivos preferenciais os canídeos domésticos. A prevalência desta doença tem vindo a aumentar, contudo, é pouco conhecida pela população em geral. Devido à sua morbilidade e caráter zoonótico tem grande importância Médico- Veterinária e para os proprietários de cães;Abstract: Traineeship report in clinic and surgery of companion animals. The traineeship referred to in this report was carried out at the Veterinary Hospital of the Lower Alentejo, in Beja, between 15/09/2014 and 15/03/2015, under the guidance of Dr. André Cláudio. The first part presents the casuistry observed during this traineeship and the second part consists of a monograph regarding the topic "Canine heartworm disease" where a literature review followed by a case is presented. The canine heartworm disease is an endemic disease in Portugal caused by nematodes of the genus Dirofilaria, whose preferred definitive hosts are domestic canids. The prevalence of this disease has increased, however, is little known by the general population. Due to its morbidity and zoonotic characteristics, has great importance in the Medical Veterinary field and for the dog owners.