Ehrlichia spp. infection worsens cardiac damage in dogs with canine visceral leishmaniasis.

In endemic areas for canine visceral leishmaniasis (CVL), the occurrence of coinfection with other pathogens, such as Ehrlichia spp., has been associated with worsening of the clinical condition. The study aimed to evaluate the occurrence of histological changes in the myocardia of dogs naturally infected with Leishmania chagasi with or without coinfection with Ehrlichia spp.. We evaluated paraffin-embedded myocardial sections from 31 dogs, affected by either L. chagasi alone or coinfected with L. chagasi and Ehrlichia spp., to compare the extent and degree of cardiac damage. The blocks were divided into two groups. G1 (dogs infected only by L. chagasi) and G2 (dogs coinfected with L. chagasi and Ehrlichia spp.). The right atrium free wall, right ventricle free wall, left ventricle, and interventricular septum of all groups were evaluated. Cardiac alterations were observed in 41.93% (52/124) of the fragments evaluated and inflammatory infiltrate was the most common pattern found. The G2 group showed a higher incidence of myocarditis, with 61.53% (32/52), compared to the G1 group, in which 20 out of 72 cases (27.7%) exhibited histopathological changes (p <0.05). These findings confirmed that coinfection can potentiate cardiac damage in dogs.

Refrigerated modified Knott concentrate enables long-term morphological viability of canine blood microfilariae.

There are several methods of laboratory diagnosis of filarids, the most used are the thick smear and the Knott method. Both are quick to perform, have a low cost and allow observing the presence, quantifying and analyzing the morphological characteristics of microfilariae. Knowing the morphological viability of fixed microfilariae is of practical importance, as it allows the transport of samples to a laboratory, facilitates epidemiological studies , and allows the storage of samples for didactic. Thus, the aim of this study was to evaluate the morphological viability of microfilariae fixed in the refrigerated modified knott test using 2% formalin. To perform the modified Knott technique, 10 samples of microfilaremic dogs aged over 6 months were used. To evaluate the morphological viability time of the microfilariae in the modified Knott concentrate, the evaluations were repeated after intervals of 0, 1, 7, 30, 60, 120, 180, 240, and 304 days. In the present study, we did not verify any difference in the morphology of the microfilariae in any of the analyzed intervals from day 0 to 304 days, and it is possible to conclude that the use of 2% formalin in the modified Knott technique allows the microfilariae to be identified in a period of 304 days. days after processing the sample without changes in its morphology.

Existem diversos métodos de diagnóstico laboratorial de filarídeos, os mais utilizados são a gota espessa e o método do Knott. Ambos são de rápida execução, possui baixo custo e permitem observar a presença, quantificar e analisar as características morfológicas das microfilárias. Conhecer a viabilidade morfológica das microfilárias fixadas tem importância prática, pois permite o transporte de amostras para um laboratório, facilita estudos epidemiológicos, e permite o armazenamento de amostras para fins didáticos. Desta maneira, o objetivo do trabalho foi avaliar a viabilidade morfológica das microfilárias fixadas em teste do knott modificado refrigerado utilizando formalina a 2%. Para realização da técnica de knott modificado foram utilizadas 10 amostras de cães microfilarêmicos, com idade superior a 6 meses. Para avaliar o tempo de viabilidade morfológica das microfilárias no concentrado de Knott modificado, foram repedidas as avaliações após intervalos de 0,1,7, 30, 60, 120, 180, 240 e 304 dias. No presente estudo não verificamos diferença na morfologia das microfilárias em nenhum dos intervalos analisados deste do dia 0 até 304 dias, sendo possível concluir que a utilização da formalina a 2% na técnica de Knott modificada permite que as microfilárias possam ser identificadas em período de 304 dias após o processamento da amostra sem que ocorram alterações na sua morfologia.