Acta Scientiae Veterinariae

Host Skin during Tick Infestation: Unearthing the Local Immunity to Lead an Anti-Tick Vaccine

2025-03-19T21:12:53-03:00

Background: The host skin is the first line of defense against most microorganisms and parasites such as bacteria, fungi and ticks. The immune system present in skin takes part of a sophisticate defense mechanism, firstly as physical, cellular and chemical barriers, followed by a wide range of antimicrobial molecules and specialized immune cells. These cells are responsible for inflammatory processes, antigen uptake and presentation, allergic responses that untimely could control the pathogens.
Review: Concerning tick parasitism, skin immunity has a paramount role during tick attachment and blood feeding through both the innate and adaptive responses. In recent years, an increasing number of discoveries in tick physiology revealed a more detailed picture of the role of immune cells and their mediators against tick parasitism. Therefore, a systematic review and summarization of this information can give a more comprehensive understanding of the orchestration of the diverse and complex host immune response mechanisms that reject at least part of infesting ticks and give clues to suggest potential applications to develop better methods for tick control.
Conclusion: The local skin immune response to tick and other ectoparasite infestations is intricately influenced by the microenvironment created by parasite attachment components and secreted proteins, attracting and engaging local immune cells. Host immune status further contributes to this dynamic. This review discusses the major cellular responses, functional diversity, and host skin immunity mechanisms stimulated by ticks. However, more research is needed to fill existing gaps and fully understand how the skin responds to ticks and other parasites. For example, studying B-cell responses, their diversity, and exploring the full Th2 immune response could provide valuable insights for improving tick control strategies.
Keywords: tick, skin, immunity, parasite, vaccine

Quadriceps Contracture in Companion Animals - Physical Therapy

2024-07-09T11:26:33-03:00

Background: Quadriceps muscle contracture (QC) that develops because of orthopedic interventions in the distal femur, proximal tibia or knee joint is a difficult process and may require a new series of orthopedic surgeries. However, despite everything, the prognosis is considered poor. The use of various physical therapy methods in musculoskeletal system and pain control is becoming more common in veterinary practice. This study aimed to investigate the effectiveness of transcutaneous electrical nerve stimulation (TENS), therapeutic ultrasound (TU) and low-level laser therapy (LLLT) applications in the treatment of QC in 1 cat and 6 dogs.

Materials, Methods & Results: The study was conducted on 6 dogs and 1 cat diagnosed with QC. All animals had undergone previous surgery. TENS+TU+LLLT was applied to the animals in the study for physical therapy for 3 or 4 weeks. The findings of the study were found to be extremely satisfactory, in terms of opening the muscle contracture and regaining the use of the leg. After each case was examined clinically, the relevant extremity was evaluated orthopedically. The hip-knee joint, femur, tibia and surrounding soft tissues were examined. Quadriceps femoris muscle (QFM) tension, knee and knee joint range of motion, QFM atrophy, pain, hip joint function, abduction and adduction ranges were examined. In addition, the patient's history and the development of the disease were noted to determine the etiology. Additionally, craniocaudal and mediolateral X-ray images of the extremity were taken. The diagnosis of quadriceps contracture was made based on clinical examination findings. Physical therapy was then planned with TENS, TU and LLLT sequences. When the cases were evaluated, it was understood that some of them were caused by faulty/insufficient and malpractice practices (4 cases), while some (3 cases) developed QC due to the patient's inability to use their extremities. In all cases, the knee joint was stiff, and it was very difficult to move the joint. The quadriceps muscles were stiff and atrophied. No problems or difficulties were experienced in the implementation of physical therapy procedures. In the animals that the owner showed interest, it was noticed that the knee joint gap and contracture started to decrease after the 2nd session and the recommended passive movements were performed at home. In the other patients, there was a significant relief at the end of the 1st week. At the end of the 3rd week, the animal was able to use its extremities clinically and the owner was satisfied. No case required surgical treatment for QC.

Discussion: Treatment options for QC, which often develops after incorrect or poor/insufficient orthopedic interventions, are limited even today. The patient remains in a situation that can lead to amputation of the relevant extremity. In addition, it is known that strain or hyperflexion movements during physical therapy will cause ruptures or fractures at the point where the muscle attaches to the tibia. In our study, different physical therapy applications such as TENS, TU and LLLT were used in combination without applying any force or pressure to the region. Of course, different doses and durations than the ones we chose could have been chosen, but the patient owner constantly stated that the patient's pain was relieved in our applications. In addition, it was clearly seen that the muscle contraction began to resolve significantly at the end of the 1st week of treatment and the knee joint range of motion began to increase. As a result, it should be known that in cases where QC develops, with effective physical therapy in the early period, the patient can regain his/her former health and surgery will not be necessary.

Keywords: cats, dogs, low level laser therapy, LLLT, transcutaneous electrical nerve stimulation, TENS, therapeutic ultrasound, TU.

Airsacculitis - Molds Isolated from Lungs of Broilers from Slaughterhouse under Control of the Federal Inspection Service

2024-10-21T13:27:10-03:00

Background: Molds are filamentous saprophytic fungi with worldwide distribution, which are found in various environmental substrates. Among them, the Aspergillus genus stands out as one of the main causes of lung disease. Commercial poultry such as chickens and turkeys, as well as captive and free-ranging wild birds species are most frequently affected. The infection occurs by the inhalation of conidia, which are dispersed in the air by wind. The most frequent acute clinical manifestation is usually observed in young animals, often with episodes of outbreaks in poultry farms, whereas chronic disease is more frequently observed in adult birds. In slaughterhouses, carcass inspection is very important for the detection of certain diseases and for monitoring their occurrence. The objective of this study was to assess the occurrence of aerosacculitis caused by molds in commercial broilers slaughtered in one establishment under Federal Inspection Service (SIF) through mycological, histopathological and molecular diagnosis.
Materials, Methods & Results: The samples (n = 76) came from 9 flocks localized in the Vale do Taquari - State of Rio Grande do Sul, RS, Brazil. Lungs were collected from broilers with airsacculitis, directly from the slaughter line and kept under refrigeration (4 oC). The evaluation and condemnation of carcasses were performed by the sanitary inspection department of the slaughterhouse. The molds were identified as the causal agent through fungal culture, histopathology and PCR analysis. Sixteen (21.0%) lung samples were positive in mycological culture, being Aspergillus sections Fumigati and Flavi the most frequent, and 2 (2.7%) samples showed fungal elements (hyaline, branching septate hyphae). The respective isolates were identified as Aspergillus fumigatus sensu stricto following the amplification of β-tub gene fragments and gel electrophoresis. Among the remaining 58 samples: no fungal growth in 61.9% (47/76) cultures and in 14.4% (11/76) were isolated colonies of hyaline septate fungi and of zygomycetes which were considered as common environmental fungi belonged to genera: Aspergillus, Penicillium, Fusarium, Scopulariopsis, Mucor and Rhizopus.
Discussion: Poultry become infected through aspiration in large numbers of conidia of molds. According to the literature,
A. fumigatus sensu stricto, which belongs to the section Fumigati, is the most ubiquitous in the environment and frequently associated with lung diseases in humans and animals. Identification of fungi to species level is important in order to determine the etiology of the disease and also to detect potential novel agents. Our results corroborate previous studies that showed A. fumigatus to be the prevalent etiological agent identified in commercial poultry. Although in smaller quantities, isolates of the section Flavi were also recovered from the lungs of healthy chickens. In the present study, only A. fumigatus was cultivated from airsacculitis cases. In poultry, many environmental factors may be present and influence the development of aspergillosis, including excessive ammonia and humidity, inadequate temperature and degraded litter. Our results are in agreement with other research where Aspergillus was detected in the lungs of chicken condemned by the inspection service. The eco-epidemiology of Aspergillus sections Fumigati and Flavi needs to be reevaluated, especially considering the transmission from environment to animals and humans. Further studies should be conducted in order to correlate clinical aspects with molecular diversity and antifungal profile among Aspergillus, as well as, investigate mold diversity isolated from commercial poultry in locations where the poultry industry is economically significant.

Keywords: moulds, Aspergillus spp., Aspergillus section Fumigati, Aspergillus section Flavi, poultry, airsacculitis.

Osteotomy Gap Consolidation in Dogs after Tibial Tuberosity Advancement with and without Cancellous Bone Graft

2024-10-31T14:48:33-03:00

Background: Cranial cruciate ligament disease is the leading cause of lameness in dogs. The application of autogenous cancellous bone graft within the osteotomy gap has been indicated to accelerate bone healing, but prospective clinical studies evaluating the effects of autogenous cancellous bone graft on osteotomy gap healing after TTA have produced mixed results. The aim of this study was evaluate bone healing time in dogs with cranial cruciate ligament disease that underwent osteotomy for tibial tuberosity advancement with or without autogenous cancellous bone graft. We hypothesized that an autogenous cancellous bone graft would accelerate bone consolidation after tibial tuberosity advancement.

Materials, Methods & Results: A total of 30 dogs (8 male; 22 female) of various breeds with unilateral or bilateral cranial cruciate ligament disease (CCLD), a minimum weight of 20 kg (44 lbs), and a tibial plateau angle up to 25° were randomly assigned to Group A [15 dogs; graft] or B [15 dogs; control]. Dogs underwent tibial tuberosity advancement (TTA) with [Group A] or without [Group B] autogenous cancellous bone graft harvested from their tibia. All surgical procedures were performed by the same experienced orthopedic surgeon. They were assessed through monthly radiographs (at postoperative [PO] day 30, 60, 90, and, as required to cover complete healing, 120, 150, 180, and 210 days). Radiographic evaluation was conducted by an experienced veterinarian who was familiar with the TTA procedure and was blinded to the treatment group (images without identification - name/group). Significantly more dogs in Group A achieved 100% osteotomy gap consolidation at 30 days PO (P = 0.0002) and 60 days PO (P = 0.0016) than Group B. The average time to 100% bone consolidation was 56 days (± 15.4) for Group A and 108 days (± 46.47) for Group B, and was significantly shorter for group A (P < 0.0001).

Discussion: Our results have showed bone consolidation time in dogs with CCLD undergoing the surgical technique of TTA is significantly faster when aided by an autogenous cancellous bone graft at 30 and 60 days PO. Therefore, we accept our hypothesis that autogenous cancellous bone graft accelerates bone consolidation. These results support the findings of another study, that noted that the use of autograft resulted in significantly higher osteotomy healing scores at 6 and 10 weeks postoperatively. The divergence of results between studies evaluating osteotomy gap consolidation following TTA may be partly explained by the subjective and different methods of bone consolidation evaluation used in these investigations. This is a standard limitation when using radiographic evaluation, however, the selection of this method is justified by the fact that this imaging modality is commonly used in routine clinical practice to evaluate bone consolidation – it is, therefore, clinically representative. The present study is subject to certain limitations. Firstly, variables other than bone graft treatment may have influenced bone consolidation time, such as age, weight, and cage size. However, these variables were not significantly different between the evaluated groups (P > 0.05), thus eliminating the effects of these potentially confounding variables. Secondly, the investigator evaluating radiographic bone consolidation could not be completely blinded to the treatment group, as some degree of radiation attenuation was associated with the cancellous bone graft. In conclusion, one consolidation time in dogs with CCLD undergoing the surgical technique of TTA is significantly faster when aided by an autogenous cancellous bone graft.

Keywords: stifle, knee, TTA, cranial cruciate ligament, rupture.

Feline Interstitial Cystitis - Analysis of Clinical-epidemiological Findings and Inflammatory Biomarkers

2024-12-01T18:08:49-03:00

Background: Feline Interstitial Cystitis (FIC) is a prevalent condition within Feline Lower Urinary Tract Diseases (FLUTD), frequently affecting male, mixed-breed cats aged 1-10 years. Despite its high incidence, data on FIC in Ceará, Brazil, remain limited. This study evaluates the prevalence of FIC among cats treated at the Veterinary Hospital of Ceará State University (UECE) and explores the utility of inflammatory biomarkers, including the serum albumin/creatinine ratio (SACR) and urine specific gravity/albumin ratio, as potential diagnostic and prognostic tools for disease monitoring.

Materials, Methods & Results: This study evaluated 227 cats diagnosed with FIC among 3,900 treated at the Veterinary Hospital of Ceará State University, indicating a prevalence of 5.82%. Data were collected on sex, age, reproductive status, diet, clinical signs, urinalysis results, and laboratory parameters including urine specific gravity (USG), creatinine, albumin, and inflammatory biomarker ratios (SACR and USG/albumin). Of the 227 cats, 102 presented with the obstructive form (OC) and 125 with the non-obstructive form (NOC). All OC cats were male, 75% were intact, and 25% neutered, while 56% of NOC cats were female. The clinical signs observed in OC cats included hematuria (69.6%), dysuria (50%), periuria (19.6%), stranguria (18.6%), and polyuria (4.9%). Dry food predominated as the primary diet in 80% of OC and 83% of NOC cats. Urinalysis showed struvite crystals in 41% of OC and 28% of NOC cats, while 55.8% of OC and 69.6% of NOC cats had no crystals. Laboratory analysis revealed no significant differences between groups for USG, creatinine, and albumin levels. However, SACR values were lower in OC cats compared to NOC cats, and the USG/albumin ratio showed no statistical difference between groups.

Discussion: This study highlights the prevalence of FIC at 5.82% in cats treated at the Veterinary Hospital of Ceará State University, providing important insights into its clinical and epidemiological characteristics. The findings confirm that male cats are disproportionately affected by the obstructive form (OC), with 100% of cases occurring in males, of which 75% were intact. Hematuria, dysuria, and periuria were the most frequent clinical signs in OC cases, aligning with previous studies. The predominance of dry food as the primary diet in both OC and NOC groups underscores its potential role in urinary health, although no direct causation was established. Urinalysis revealed a higher occurrence of struvite crystals in OC cases (41%) compared to NOC (28%), while more NOC cats had no crystals (69.6%). These findings suggest that other factors, beyond crystalluria, contribute to the inflammatory processes underlying FIC. The significant reduction in serum albumin/creatinine ratio (SACR) in OC cats emphasizes its potential as a biomarker for inflammation and impaired renal function. However, the lack of difference in USG/albumin ratio between groups suggests that additional studies are needed to validate its clinical utility. In conclusion, the study underscores the epidemiological and clinical relevance of FIC, emphasizing the potential of SACR as a diagnostic and monitoring tool. Further prospective studies are encouraged to deepen the understanding of the disease’s pathophysiology and explore the role of inflammatory biomarkers in its management.

Keywords: lower urinary tract disease, urine specific gravity, epidemiology, albumin to creatinine ratio.

Feline Panleukopenia - Effects of Treatment with Filgrastim on Mortality, Hematological and Biochemical Parameters

2024-11-26T08:28:16-03:00

Background: Panleukopenia is a highly contagious and fatal disease of cats. Although infection may be prevented by intensive vaccination of animals in the home environment, infection is frequently seen in stray animals that are not vaccinated and are in contact with the virus. Treatment protocols in the disease consist of classical supportive therapies because there is no specific antiviral drug. The aim of this study is to evaluate the effects of Filgrastim administration on mortality, complete blood count, and serum biochemical parameters in the treatment of cats infected with Feline Panleukopenia Viruses (FPV).
Materials, Methods & Results: The study population consisted of 2-6 months old cats of different breeds and sexes who were brought to our clinic with complaints of lethargy, anorexia, high fever, diarrhoea and vomiting. A complete blood count was taken from the symptomatic patients during physical examination and FPV Ag test was performed. Fourteen cats with positive FPV antigen test and 7 healthy cats with negative FPV Ag test without clinical symptoms were included in the study. The study included 7 Panleukopenia-infected cats treated with Filgrastim in addition to conventional supportive therapy, 7 Panleukopenia-infected cats treated with conventional supportive therapy, and 7 healthy cats. Complete blood count and serum biochemical parameters were analyzed from the samples taken from the patients on days 0, 3 and 7. As a result of the treatment, the mortality rate was 14.28% in both groups. In this study, it was observed that the administration of Filgrastim (Group 1) had statistically significant results on WBC (P < 0.009), lymphocytes (P < 0.009) and granulocytes (P < 0.003) between days 0 and 7 in cats with FPV. This suggests that the administration of Filgrastim in addition to supportive therapy increases the number of lymphocytes and granulocytes. The administration of Filgrastim as an adjunct to supportive therapy had no effect on the serum biochemistry values of the patients. In conclusion, the administration of Filgrastim in the treatment of panleukopenia did not result in a change in the mortality rate.
Discussion: The incidence of FPV decreases as the age of the animal increases. In cats aged 3-5 months, the amount of antibody from the mother decreases. In this study, it was determined that the age of all FPV Ag positive cats included in group 1 and group 2 was 2-6 months. It has been reported that there may be a rapid increase in neutrophil counts in cats with FPV treated with filgrastim. In this study, it was observed that the use of Filgrastim (Group 1) in cats with FPV produced statistically significant results on WBC, lymphocytes and granulocytes between days 0 and 7. This shows that the use of Filgrastim in addition to supportive therapy increases the number of lymphocytes and granulocytes. The incidence of FPV decreases as the age of the animal increases. In cats aged 3-5 months, the amount of antibody from the mother decreases. In this study, it was determined that the age of all FPV Ag positive cats included in group 1 and group 2 was 2-6 months. Serum biochemistry parameters are not specific for FPV. Hypoalbuminaemia is the most common abnormality, probably due to decreased protein intake and leakage from mucosal lesions into the gastrointestinal tract. Similar to the literature, no significant change was observed in biochemical parameters. In addition, serum biochemical examinations have shown that Filgrastim can be administered to cats without any side effects. Before administering an immune modulator such as G-CSF, the stage of the disease and the status of the immune system should be taken into consideration.

Keywords: panleukopenia, filgrastim, granulocyte colony stimulating factor, feline parvovirus infection

Ovum Pick Up: Which Day of the Estrous Cycle Should be Performed in Cattle?

2024-10-20T04:43:46-03:00

Backgraund: The first step in the in vitro embryo production (IVEP) procedure is to obtain high-quality and viable oocytes. Therefore, the ovum pick-up (OPU) method was developed in cattle. Ovum pick up in cattle is usually performed once or twice a week. However, when a fixed time follicular aspiration procedure is planned, the OPU application is conducted on different days of the donor's estrous cycle. Furthermore, there is no recommendation as to the optimum day within the estrous cycle for OPU. Therefore, the main objective of the present study was to determine the effect of OPU application on oocyte yield, quality and blastocyst rates on different days of the estrous cycle.

Materials, Methods & Results: In the study, 18 Holstein heifers received OPU on days 2-3, 4-7, 8-12 and 13-16 of the estrous cycle. The OPU application was performed once in one oestrus cycle for all donors. The following OPU application waited at least one estrous cycle. Grade A quality oocytes were obtained in greater numbers in D 2-3 and D 4-7 groups than in D 13-16 group (P < 0.05). There was no difference in other oocyte quality and total number of oocytes between the groups. The number of viable oocytes was similar between D 2-3 and D 4-7 groups, but greater than D 13-16 group (P < 0.05). Concurrently, the number of viable oocytes was greater in D 4-7 group than in D 8-12 group (P < 0.05). There was no difference between D 2-3 and D 8-12 groups in terms of viable oocyte number. The number of blastocysts in D 2-3 and D 4-7 groups was greater than D 8-12 and similar to D 13-16 (P < 0.05).

Discussion: A follicle may be in 1 of 4 phases during the follicular wave: growth, dominance, static, or regression. In present study, the greater number of oocytes with greater quality and viability rate in D 2-3 and D 4-7 groups is thought to be due to the absence of follicles in the dominant stage in these two groups. In OPU/IVEP method, a greater number of oocytes per donor increases the rate of blastocysts and viable embryos and accordingly positively affects the post-transfer pregnancy rate. In current study, the number of Grade A oocytes and viable oocytes were greater in D 2-3 and D 4-7 groups of the cycle compared to D 13-16 group of the cycle. The reason for this is that when OPU is used on days 13-16 of the cycle, different follicular groups can be found on the ovary. In addition, the present study demonstrated that the number of viable oocytes and blastocysts was greater in the D 4-7 group compared to the D 8-12 group. This may be due to the greater number of atresia follicles (subordinal follicles) between days 8-12 of the cycle (compared to days 4-7) and the lower developmental competence of oocytes in the subordinal follicle. The most significant factors influencing the success of an in vitro embryo production process are the quality and viability of the oocyte. In the present study, the number of Grade A oocytes was greater in the D 2-3 and D 4-7 groups than in the D 13-16 group, but there was no difference in the number of blastocysts. However, in parallel with the number of viable oocytes, the number of blastocysts obtained in groups D 2-3 and D 4-7 was greater than in group D 8-12. In conclusion, the determination of the appropriate day of the cycle for OPU will rule out synchronisation or stimulation of the follicular wave and ablation of the dominant follicle. Therefore, the oocyte quality, number and most importantly the number of blastocysts can be increased by performing OPU between 2-3 or 4-7 days of the estrous cycle.

Keywords: blastocyst, holstein heifer, luteal phase, oocyte quality, ovum pick up.

Orf Virus (ORFV) Infection in the Mouth of Lambs and Kids Detected by Molecular Investigation

2024-09-22T17:28:09-03:00

Background: Contagious Ecthyma infections caused by Parapoxvirus ovis are an important viral disease of sheep and goats. It is an infection with high mortality that especially affects young animals. The majority of orf virus (ORFV) infections are diagnosed using molecular diagnostic techniques (multiplex, conventional, real-time PCR). Scab samples were collected from lesions developed due to ORFV in the mouths of 50 lambs and 50 kids that were not vaccinated against ecthyma disease from public pens in Burdur-Center and surrounding areas. The main objective of the study was to investigate the ORFV genome in the samples using the conventional PCR method with 25 different types of primers.

Materials, Methods & Results: Scab samples were collected from lesions defined because of ecthyma disease in the mouth (lips, gums) of 50 lambs and 50 kids aged ≤ 1 month to 3 months in various public pens. In the study, high viral genome positivity was determined in local breed lambs (Sakiz sheep; 40%) and kids (Kil goat; 36%). ORFV genome presence was detected more positivity in female lambs (60%) and kids (46%) than in males. ORFV genome presence was detected more positivity in lambs (36%) and kids (40%) aged ≤ 1 month, than in those in the 2- and 3-month age group. In this study, with use of PCR applications, ORFV was predominantly detected in the Burdur region; GIF/IL2, PPP1-PPP4, Orf1-Orf2, VIR1 VIR2, vIL-10-3 vIL-10-4, B2L and Alpha tubulin primers was detected. No positivity was obtained in PCR analysis using PPV JGR, ORFV 011-B and ORFV 109 primers. In our study, it was found that the groups with the most binary ORFV primers were found at the highest rate in the tissues.

Discussion: Contagious Ecthyma infection caused by Parapoxvirus ovis is an important viral disease of sheep and goats. It is an infection with high mortality that especially affects young animals. The infection primarily affects animals under one year of age, and it also affects animals three to four months after birth. Therefore, it is a disease that causes both economic and productivity loss. Due to factors like weight loss and weakened immunity brought on by limited amounts of breast milk and feed intake because the lesions are in the mouth, ecthyma has a more severe effect on lambs and kids than it does on adults. The susceptibility of animals to secondary infections may increase. Young animals die at a higher rate as a result. The mortality of the majority of the offspring in that herd at that time and the development of productivity losses are indicators of the spread of ORFV in small cattle farms over time. Many classical diagnosis methods are used in the disease. Molecular diagnostic methods are mainly used in ORFV infections because they are sensitive, rapid and low-cost. One of these is the PCR application, which is used worldwide and in Turkey and yields findings more quickly than other techniques. In the research, the presence of viral genome was investigated by PCR using 25 different types of primers in the oral lesions of lambs and kids. In this study, the presence of ORFV in lesions occurring in the mouth area of lambs and kids was investigated molecularly. In the current study, ORFV was detected in most of the 7 primers, and the groups with the most binary ORFV primers were found at the highest rates in the tissues. As a result, the presence of ORFV was detected molecularly in the lesions occurring in the mouth area of lambs and kids of different breeds.

Keywords: ecthyma, kid, lamb, PCR, Orf virus.

Canine Experimental Autoimmune Encephalomyelitis: Potential Therapeutic Effect of Fingolimod

2024-07-29T01:55:11-03:00

Background: Meningoencephalitis of unknown etiology (MUE) is a representative sterile inflammatory disease of the central nervous system (CNS) in dogs. The treatment involves the use of immunosuppressive therapies. Despite intensive immunosuppressive therapy, the survival time of MUE remains short. Fingolimod is a novel immunomodulatory drug primarily used to treat human neuroinflammatory diseases such as multiple sclerosis. However, fingolimod has not yet been used in veterinary medicine. Therefore, this study aimed to identify the potential therapeutic effect of fingolimod as an alternative treatment agent for MUE in dogs, using a canine experimental autoimmune encephalomyelitis (EAE) model.

Materials, Methods & Results: The canine EAE model was induced using brain tissues obtained from client-owned dog. Eight grams of forebrain tissue were homogenized in an ice bath for 5 min with phosphate-buffered saline. The resulting suspension was emulsified with an equal amount of Freund’s complete adjuvant. A laboratory Beagle dog was subcutaneously injected with the homogenate in the axillary and inguinal regions (a total of 4 sites) under sedation. The dog received a booster injection 7 days later using the same procedure as the 1st injection. After 25 days of the 1st injection, the dog showed decreased activity and hyporexia. When a magnetic resonance imaging (MRI) examination was performed to determine whether the inflammatory lesion was induced, a lesion in the left white matter of the frontal lobe was identified as hyperintense in T2-weighted and fluid-attenuated inversion recovery images and hypointense to isointense in T1-weighted images. Additionally, cerebrospinal fluid analyses revealed a slight increase in total protein concentration and severe mononuclear pleocytosis. The EAE dog was prescribed oral fingolimod [0.05 mg/kg once daily]. At 14 and 28 days post-fingolimod therapy, assessments of clinical signs and 2nd and 3rd MRIs were performed to evaluate therapeutic effectiveness. The clinical signs and most lesions were no longer observed. CSF analysis results were also normal at 14 and 28 days after the commencement of fingolimod therapy.

Discussion: The canine EAE model and MUE share several key similarities, making the EAE model a valuable tool for studying MUE. Both conditions are characterized by immune-mediated inflammation of the CNS, leading to demyelination and neurological deficits. The treatment approaches for both conditions often involve the use of immunosuppressive therapies to control inflammation and prevent further neurological damage. These similarities in pathogenesis, clinical presentation, and therapeutic strategies emphasize the relevance of the EAE model in understanding the mechanisms underlying MUE and in developing effective treatments for MUE. Fingolimod was known to be well tolerated and effective, causing a swift decrease in peripheral lymphocytes without any adverse effects at oral doses ranging from 0.01 mg/kg to 0.1 mg/kg in dogs. Despite being a single case, this study evaluated fingolimod as a novel immunomodulatory agent for MUE. When applied for 4 weeks in a canine EAE model, fingolimod revealed a remarkable therapeutic effect by showing recovery of clinical signs, resolution of MRI lesions, and normalization of abnormal CSF findings. Therefore, fingolimod has shown potential as an alternative novel treatment agent for dogs with MUE.

Keywords: dog, EAE, fingolimod, treatment, meningoencephalitis, MUE, S1PR.