Canine Monocytic Ehrlichiosis (CME) is a systemic disease prevalent in the entire world caused by the obligate intracellular bacteria Ehrlichia canis . The occurrence of myocarditis with a high prevalence of arrhythmias in dogs affected by this disease in the cytopenic phase has already been proven. This study aims to evaluate the concentrations of CK MB, cTnI and NT-proBNP in dogs affected by Ehrlichia canis in the chronic phase since the intense stimulation of the immune system can lead to myocarditis; to evaluate if the condition can lead to arrhythmic events and, if so, define their frequency and classification through conventional and ambulatory electrocardiogram tests (Holter method) for a period of 24 hours; to analyze heart rate variability in the time domain and whether the condition can lead to autonomic imbalance; and to determine the survival rate of affected dogs, identifying possible risk factors for mortality at this stage of the disease. For this purposes, we evaluated clinical, hematological and biochemical data, as well as the concentrations of cardiac biomarkers Creatine Kinase-MB (CK MB), Cardiac Troponin I (cTnI) and N-terminal pro-peptide natriuretic type B (NT-proBNP). We also analyzed conventional and ambulatory electrocardiography (24-hour Holter) and heart rate variability (HRV) in 20 dogs afflicted by cytopenic CME in the chronic phase of the disease (G1) and compared the results with a control group comprised of ten healthy dogs (G2). G1 was monitored during the treatment for 28 days, during which eight (8) of the 20 infected dogs died (40%). Anorexia, vomiting, fatigue, hypoalbuminemia, heart murmurs and increased concentrations of alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were common clinical signs. The mean concentrations of cTnI and CKMB were significant (0.24 ng / mL ± 0.5, 229 ± 205 IU / mL) in comparison to the control group (0.042 ± 0.07 ng / mL, 126 ± 46.12 IU / mL). No significant differences were observed between NT-proBNP concentrations in G1 (135.46 ± 29.7) and G2 (138.28 ± 19.77). Nine of the twenty dogs (45%) presented a high frequency of arrhythmias during 24-hour recording, ranging from first and second-degree atrioventricular block, ventricular and supraventricular ectopic events and sinus tachycardia. No sinus pause was observed. One dog had 120 episodes of unsustained ventricular tachycardia and two episodes of sustained ventricular tachycardia. The short-term and long-term HRV data, represented by SDNN (ms), SDANN (ms) and pnn50 (%) were also significant lower (83 ± 65, 56.05 ± 37.3 and 14.56 ± 20, respectively) in comparison to the healthy animals (268 ± 74.6, 168.3 ± 39.14 and 55.87 ± 12.8, respectively). These results suggest that cytopenic CME is characterized by an arrhythmogenic component and intense stimulation of the sympathetic autonomic nervous system in the heart, reflecting an imbalance in the activity of the ANS.

Com a relação mais estreita entre as pessoas e os animais, as zoonoses tornam  se mais  importante na saúde pública. Entre elas podem ser destacadas a raiva, leishmaniose, brucelose canina, febre maculosa, toxoplasmose e leptospirose que apresentam aspectos epidemiológicos e de controle diferentes entre elas. A Raiva é 100 % fatal em animais e humanos, causando encefalomielite aguda, sendo considerada ainda grave problema de saúde pública. Desde as décadas de 1950 e 1960, quando houve elevado número de casos de raiva humana transmitida principalmente por cães no Brasil, pôde-se observar uma preocupação nas atividades governamentais, como por exemplo a implantação do “Programa Nacional de Profilaxia da Raiva Humana” (PNPR) em 1973, a nível nacional, e posteriormente, em 1983 o “Plano de Ação para Eliminação da Raiva Urbana das Principais Cidades da América Latina”, desenvolvido pela Organização Pan-Americana da Saúde (OPAS). Alguns avanços foram obtidos no controle dessa doença, com redução do número de casos humanos, tendo sido reportado apenas um caso de raiva humana no Brasil em 2015. A Leishmaniose Visceral Canina (LVC) vem sem expandindo no Brasil. É uma zoonose de extrema importância para a saúde pública. Seu agente etiológico é um protozoário do gênero Leishmania, transmitido pela picada de mosquitos flebotomíneos. Os cães são os principais reservatórios primários da doença, enquanto os humanos, os hospedeiros acidentais. Esta doença em cães traz muita polêmica, já que o Ministério da Saúde juntamente com o Ministério da Agricultura Pecuária e Abastecimento (MAPA) criaram a Portaria Interministerial nº 1426 que proíbe seu tratamento com produtos de uso humano ou não registrados no MAPA, recomendando a eutanásia dos cães infectados ou doentes. A Brucelose canina é caracterizada como uma antropozoonose infecciosa crônica, que apesar de menor incidência na população humana, possui grande importância socioeconômica, pois é a principal causa de infertilidade em canídeos domésticos em todo o mundo e trata-se de uma zoonose ocasional, mesmo no caso da doença em cães que pode infectar humanos em suas atividades laborais, principalmente no caso de cães de canil. A Febre maculosa brasileira é causada pela bactéria gram negativa, intracelular obrigatória, Rickettsia rickettssi tem como vetor o carrapato Ixodideo Amblyomma cajennense. Com a proximidade das áreas urbana e rural, a incidência da doença em humanos tem aumentado, já que a exposição ao vetor e aos animais infectados ou doentes  é cada vez mais frequente. A doença tem evolução aguda e seu diagnóstico rápido é importante, pois pode ser fatal na maioria dos casos, se não houver a instituição do tratamento rapidamente. A Toxoplasmose é uma das zoonoses de ampla difusão mundial, causada pelo protozoário Toxoplasma gondii, que apresenta três genótipos distintos. Tem como hospedeiro definitivo o gato e outros felideos, e devido a crescente importância como animal de estimação, há necessidade de maiores esclarecimentos sobre sua transmissão, especialmente quando há o envolvimento de gestantes. Há conceitos controversos e errôneos sobre o contato direto com esses animais e a sua transmissão. Precários hábitos de higiene e ingestão de alimentos crus são as principais fontes de contaminação em humanos, e desta forma profissionais da saúde devem orientar a população quanto a medidas essenciais de higiene para diminuir sua incidência. A Leptospirose é outra zoonose de distribuição mundial causada principalmente pela bactéria Leptospira interrogans, e afeta diversas espécies de mamíferos domésticos e selvagens. Os cães e o gatos além de outras espécies animais eliminam leptospiras pela urina, tendo importante papel epidemiológico na sua disseminação, que prevalece em locais com falta de saneamento básico. A bactéria penentra no organismo pelo contato com água ou urina contaminada, pela pele lesada e mucosas. Vencendo as defesas naturais do organismo se aloja principalmente no rim e fígado. A vacinação e o manejo ambiental são as principais formas de prevenção.

No abstract

The evaluation of the autonomic cardiac functions may be performed through the analysis of the heart rate variability. Heart rate variability is defined as the fluctuations in the heart rhythm or rate, and represents a useful tool in the evaluation of the autonomic nervous system through the sympathetic and parasympathetic components, as well as its balance and its reflexes on the cardiorespiratory control system. Fetal electrocardiography provides important information regarding the well-being of the fetus since, in human fetuses, there are changes in the behavior of the fetal heart rate during the second and third trimesters of pregnancy due to an increase in parasympathetic activity. Therefore, considering the importance of evaluating fetal viability, this study aims at evaluating the behavior of fetal heart rate and heart rate variability in Dorper sheep, as well as the activity of the autonomic nervous system during fetal life and in newborn lambs. The species is often used in experimental studies and autonomic nervous system activity is a prognostic index, therefore, the diagnosis of modifications in the sympathovagal balance may represent an early index for fetal viability and well-being in lambs. The analyses were performed in 10 Dorper sheep during pregnancy and in 10 lambs after birth until 120 days of age. There was a decrease in the fetal heart rate and heart rate variability indexes during the fifth month of pregnancy, but without statistical significance for the period evaluated. The heart rate of the lambs decreased gradually until they were 21 days old. The indexes SDNN (standard deviation of RR intervals) and RMSSD (square root of the mean of successive differences between adjacent RR intervals) diverged according to age, being high at day 60. Fetal viability is relevant in sheep fetuses to avoid losses during pregnancy and risks to the health of the mother. In the species, there seems to be a predominance of parasympathetic activity starting from the 21st day of age. Heart rate variability may be employed as a tool in the evaluation of the fetus and development of lambs, since changes in its behavior may represent an adverse effect to fetal and neonatal health.

Background: The modulation of heart rate by autonomic nervous system may be evaluated by the heart rate variability (HRV), which illustrates the fluctuations between RR intervals. To evaluate this analysis, the intervals between 2 QRS complexes are measured. In general, high HRV values are expected in healthy individuals; otherwise, low values are indicative of organism dysfunction. Studies conducted in healthy humans show that HRV suffers reduction with ageing and that there is autonomic immaturity in neonates. The aim of this study was to describe the characteristic pattern of cardiac autonomic behavior in healthy dogs in different age groups through short-term HRV analysis.Materials, Methods & Results: A total of 87 healthy dogs were studied. HRV was analyzed in time and frequency domain, using Holter and heart rate monitor. It was observed that puppies (below one year old) presented a lower parasympathetic predominance and, consequently, lower HRV values on time domain (SDNN, PNN50% e RMSSD) compared to the other 2 groups and on frequency domain (LF, HF and LF/HF) compared to the adult animals group (between 1 and 7-year-old), which presented higher HRV values when compared to the other groups. Elderly dogs (over 8-year-old) exhibited a natural tendency to decrease cardiac parasympathetic HRV indexes.Discussion: The use of the HRV method as a prognostic index and as an arrhythmogenic marker for various canine heart diseases presents interesting perspectives. However, before it may be employed for these purposes, a better understanding should be established regarding the physiological behavior of autonomic cardiac modulation in different age groups to serve as a basis for future analyses. This study observed that puppies presented higher values for HR and, therefore, shorter RR intervals than the other groups (adult and elderly dogs), what was observed on Holter and heart rate monitor methods (HRM). There were significant differences between puppies and the other 2 groups (adults and elderly) for all time-domain variables using both methods (Holter and HRM methods). SDNN was significantly lower in puppies compared to adults and elderly dogs. In addition, both RMSSD and PNN50%, which were more reliable over shorter periods of time, also presented means and medians that were significantly lower in puppies. Regarding frequency-domain HRV parameters observed on Holter method, these indexes were decreased on the elderly group compared to adult dogs, which is a possible effect of aging. Also, puppies revealed lower frequency-domain HRV parameters on both methods when compared to adult dogs. The influence of age on HRV is possibly related to the stage of development of an individual, starting at conception up to the maturity in relation to the mechanisms that cause variations in HR. There are studies in humans that suggest a gradual increase in parasympathetic activity during childhood, followed by a steady decrease as aging occur. The present study observed the same pattern in dogs. The balance between sympathetic and parasympathetic systems is influenced by age in dogs, which alters HRV values in the short-term. The HRV method´s analysis is relatively simple and non-invasive for assessing cardiac autonomic function; also, it is widely used in human medicine as a risk measure for sudden cardiac death. The 24-hour HRV analysis is highly challenging, as it is time-consuming, expensive, delays diagnosis, and has a large number of artifacts; in this way, standards for its short-term analysis were developed. Keywords: cardiology, autonomic nervous system, heart rate monitor, Holter.