Experimental infection of BALB/c mice with felid alphaherpesvirus 1

Felid alphaherpesvirus type 1 (FHV-1) is an important cause of respiratory and ocular diseases in cats worldwide. Mice have been widely used to study the pathogenesis of several human and animal viruses, especially herpesviruses. This study aimed to verify whether BALB/c mice are susceptible to FHV-1 infection. The animals were intranasally inoculated with FHV-1 and their clinical signs were observed from 3 days post-infection (dpi). At 10 dpi, the animals were euthanized and the lungs, liver, spleen, and kidneys were collected for histopathological examination and quantitative polymerase chain reaction. The results showed that mice were infected with FHV-1 and reproduced several features of the disease observed in its natural host. Histological lesions and viral DNA were found in all sampled tissues, with a higher frequency of FHV-1 DNA copies detected in the lungs. All mice were seroconverted to FHV-1 at 7 dpi. To our knowledge, this is the first report of experimental infection of BALB/c mice with FHV-1. Our findings demonstrate that this murine model can contribute to understanding of FHV-1 pathogenesis and may be useful for trials against this virus.

Current Understanding of the Pathogenesis of Porcine Circovirus 3

Circoviruses are closed, circular, single-stranded DNA viruses belonging to the family Circoviridae and the genus Circovirus. To date, at least four porcine circoviruses (PCVs) have been recognized, including PCV1 to PCV4, respectively. Similar to PCV2 pathogenesis, PCV3 has been reported worldwide with myriad clinical and pathological presentations such as reproductive disorders, respiratory diseases, diarrhea etc. Current understanding of PCV3 pathogenesis is very limited since the majority of studies were mostly field observations. Interpretation of the results from such studies is not always simple. Various confounding factors affect the clinical appearance and pathological changes of the infected pigs. Recently, several experimental PCV3 infection studies have been reported, providing a better understanding of its pathogenesis. In this review, we focused on novel findings regarding PCV3 pathogenesis from both field observation and experimental infection studies. Possible factors involved in the conflicting results among the experimental infection studies are also discussed. This review article provides important insight into the current knowledge on PCV3 pathogenesis which would aid in prioritizing research in order to fill the knowledge gaps.

Characterization of a Nigerian Lumpy Skin Disease Virus Isolate after Experimental Infection of Cattle

Lumpy skin disease virus (LSDV), together with sheeppox virus and goatpox virus, belong to the genus Capripoxvirus within the family Poxviridae. Collectively, they are considered the most serious poxvirus diseases of agricultural livestock. Due to their severe clinical course and consequent loss of production, as well as high mortality of naïve small and large ruminant populations, they are known to have a significant impact on the economy and global trade restrictions of affected countries. Therefore, all capripox diseases are classified as notifiable under the guidelines of the World Organization of Animal Health (OIE). Since the 1970s, several outbreaks of LSD have been recorded in Nigeria. Until now, only a little information on the virus strains leading to the reported outbreaks have been published, dealing mainly with the phylogenetic relationship of those strains and the description of field outbreaks. During the present study, we experimentally infected cattle with a low-passage Nigerian LSDV strain isolated from a skin sample of LSD positive cattle in Nigeria in 2018. Clinical, molecular and serological data indicate that this LSDV isolate is highly pathogenic in cattle since it induced a severe clinical course and approximately 33% mortality in naïve Holstein Friesian cattle after experimental infection.

Effect of biotherapy T. cruzi 7x in several therapeutic schemes on experimental infection by Trypanosoma cruzi

Background: Biotherapy is used against infectious diseases treatment and prophylaxis and has been investigated by many researchers [1,2]. Aim: Assess the effect of biotherapy 7x T. cruzi on several treatment schemes, upon experimental infection by T. cruzi. Methodology: A blind, controlled and randomized by drawing experiment was performed. Male Swiss mice, four weeks old were utilized. Groups evaluated: IC – Infection Control (treated with water – 9 animals); TBBA7x3days – Treated with biotherapy 7x 3 days before and 3 days after infection (5 animals); TBB7x3days – Treated with 7x biotherapy 3 days before infection (5 animals); TBBAI7x3days – Treated with 7x biotherapy 3 days before infection and after infection indefinitely (6 animals). Animals were inoculated intraperitoneally with 1400 blood trypomastigotes Y strain. Biotherapy: prepared according to Farmacopéia Homeopática Brasileira [3]. Treatment plan: offered ad libitum, in the water (10µL/mL). Parasitological parameters: parasitemia was assessed according Brener’s technique. [4]. Clinical parameters: body hair aspect, edema, movement, diarrhea, body weight, temperature, food and water intake. Ethics: Registration 030/2008 UEM Ethics Committee for Experiments in Animals. Statistical analysis: was performed using the tests Kruskal Wallis and Mann-Whitney testes, significance 5%. Results: The best effect obtained was with the TBBA7x3days, both for clinical and parasitological parameters. It was expressed by lower parasitemia curve (p=0.04) and decrease of patent period tendency, of total parasitemia, of mortality and survival of the animals increase (Table 1). Evolution of parasitemia was distinct for the several treatment schemes. Survival of at least one mouse by treated groups is an extremely important data, since Y strain causes 100% mortality in Swiss mice. TBBAI7x3days group showed begger tendency in raising total parasitemia compared with IC. Although it might have occurred, this group presented 80% mortality rate compared with other groups. Animals from TBBA7x3days also showed better evolution of weight body, temperature, food (p=0.078-10%) and water intake, body hair aspect and edema development. Diarrhea and paralysis were only observed in IC group mice, highlighting the biotherapy use benefits. Conclusions: Best effect was obtained TBBA7x3days, both for clinical and parasitological parameters. It’s possible to speculate that in this regimen, biotherapy was able to modulate, more effectively, the host’s immune system, decreasing the number of parasites.

Evaluation of biotherapies T.cruzi 15x, 16x, 17x and "potency chords" in experimental infection by Trypanosoma cruzi.

Background: The biotherapies are drugs widely utilized against infectious diseases. Biotherapies’ profylatic and therapeutic action against Chagas Disease is currently being investigated, but it is needed to develop further controlled experiments “in vivo”, which could define more clearly: dilution, dose, time of use and, if possible, the action mechanisms of these ultradiluted medicaments [1,2]. Aim: Evaluate the effect biotherapies T. cruzi 15x, 16x, 17x and “potency chords”, on experimental infection by T. cruzi. Methodology: A blind, controlled and randomized by drawing test was performed. Animals: 29 male Swiss mice, four weeks old were utilized. The animals were kept at Parasitology Vivarium/State University of Maringá (UEM), in ideal conditions of temperature (22±2)ºC and photoperiod (light / dark cycle 12h). Mice have been inoculated intraperitoneally with 1400 blood trypomastigotes Y strain and divided in groups: IC – Infection control (treated with distilled water – 9 animals); TBBA15x3days – Treated with biotherapy 15x 3 days before and 3 days after infection (5 animals); TBBA16x3days – Treated with biotherapy 16x 3 days before and 3 days after infection (5 animals); TBBA17x3days – Treated with biotherapy 17x 3 days before and 3 days after infection (5 animals); TBBAChords3days – Treated with biotherapy 15x, 16x, 17x “potency chords”, 3 days before and 3 days after infection (5 animals). Biotherapies: prepared by a homeopathic pharmacist from UEM, according to Farmacopéia Homeopática Brasileira [3]. Biotherapies treatment schedule: diluted in distilled water (10µL/mL in ambar bottles – renewed each two days) offered ad libitum, 3 days before and 3 days after infection in all groups. Parasitological parameters: parasitemia was assessed from infection until death, according to Brener’s technique [4] with 5µL of blood collected from the tail vein and examined in optical microscope. Pre-patent period, patent period, total parasitemia, survival and morbidity were obtained from the parasitemia curve. Clinical parameters: Visually assessed (presence or absence): body hair aspect (bristling), edema, movement and diarrhea. Measured: body weight, temperature, food and water intake. Ethics: This study has been approved by the UEM Ethics Committee for Experiments in Animals - Registration 030/2008. Statistical analysis: was performed using the tests Kruskal Wallis and Mann-Whitney tests, significance of 5%. Results: There was not statistical difference between total parasitemia of the groups treated with biotherapies and the IC group (p=0.6819). The parasitemia curve of group TBBAChords3days was greater then the IC (p=0.0418). Despite this increase, patent period and mortality both showed a decreasing tendency, while pre patent period and survival time increased (p=0.373). The same tendency results were observed for TBBA17x3days results (Table 1). Survival of at least one mice in groups TBBA17x3days and TBBAChords3days is worthy of discussion, since Y strain causes 100% mortality in these experimental conditions. Groups TBBA17x3days and TBBAChords3days showed better evolution than IC group for body weight, temperature, food and water intake (p=0.05), body hair aspect and edema developing. Diarrhea and hind legs paralysis were only observed in mice belonging to groups IC and TBAA16x3days. Conclusions: Superior effect was obtained with biotherapies 17x and “Potency Chords”, both for clinical and parasitological parameters. “Potency chords” has proper effect which distinguishes it from the individual effects of the dilutions that compound it.

PATHOMORPHOLOGY OF EXPERIMENTAL INFECTION CAUSED BY DORMANT YERSINIA PSEUDOTUBERCULOSIS STRAINS

In the 2000s, with the development of scientific research on the uncultivated (dormant) state of pathogenic bacteria, the ideas about persistent, chronically recurrent infections, difficult to respond to antibiotic therapy have begun to shape. However, regarding human pseudotuberculosis (Far Eastern scarlet-like fever, FESLF), this question remains open. While analyzing the pathology of pseudotuberculosis, its clinical and epidemic manifestation as FESLF, we identified the etiopathogenetic prerequisites for the disease recurrence and development of persistent infection [3]. In this study, it was found that the strains of Yersinia pseudotuberculosis, which were in a dormant state, caused the development of a peculiar granulomatous inflammation in target organs with pronounced delayed-type hypersensitivity reactions in vivo. To reproduce the experimental infection, sexually mature white mice were inoculated with the strain 512 Y. pseudotuberculosis, serotype I sored for 10 years at the Museum of the Research Somov Institute of Epidemiology and Microbiology and transformed into a dormant state. For comparative studies, a dormant form from vegetative bacteria of the strain 512 Y. pseudotuberculosis was obtained by exposure to a large dose of kanamycin (the minimum antibiotic dose was exceeded 25 times). The infecting dose of both forms of bacteria was 108 µ/mouse. Samples of target organs (lung, liver, spleen) were collected for histological examination on days 3, 7, 10, 14, 21 and 32 after infection. Histological sections with 3-5 µm thickness were stained with hematoxylin and eosin according to standard techniques. It was established that strains of Y. pseudotuberculosis in dormant state caused in vivo development of a peculiar granulomatous inflammation due to delayed-type hypersensitivity reactions (DHR), which characterizes the protective reaction in infected host and reflects formation of local, tissue immunity in target organs. The peculiarities of granulomatous inflammation were revealed, in comparison with that of found during infection with vegetative ("wild") Y. pseudotuberculosis bacteria, namely: the granulomas were predominantly small in size, clearly delimited from the surrounding tissue, without destruction of central zone cells and formation of the so-called "granulomas with central karyorrhexis" (terminology proposed by A.P. Avtsyn) [4]; perivascular infiltrates and vasculitis consisted mainly of lymphocytes and often had a follicle-like appearance, resembling the follicles in lymphoid organs; in the lungs, a well-marked reaction of the bronchial-associated lymphoid tissue was observed, and in the spleen, a follicular hyperplasia, indicating a T-cell defense reaction, was observed. Thus, the causative agent of Y.pseudotuberculosis infection / FESLF, being in a dormant state, initiates the development of immunomorphological changes of a protective nature such as productive granulomatous inflammation with reactions of local tissue immunity in target organs and can contribute to the formation of persistent infection.

SKIN CONDITION IN EXPERIMENTAL INFECTION OF SHEEP WITH CONTAGIOUS DERMATITIS

As a result of the study, it was found that with contagious pustular dermatitis, the damage affects the epidermis and dermis of the skin. The most severe damage is recorded in the epidermis on day 9, fragments of organelles and viroplast clusters are observed in the cytoplasm. On the 22nd day, regenerative and regenerative processes prevail in the epidermis and dermis, in the form of proliferation, cell differentiation and organization of intercellular substance.