Canine Infection Research Articles

Working towards the development of vaccines and chemotherapeutics against neosporosis-With all of its ups and downs-Looking ahead.

Neospora caninum is an apicomplexan and obligatory intracellular parasite, which is the leading cause of reproductive failure in cattle and affects other farm and domestic animals, but also induces neuromuscular disease in dogs of all ages. In cattle, neosporosis is an important health problem, and has a considerable economic impact. To date there is no protective vaccine or chemotherapeutic treatment on the market. Immuno-prophylaxis has long been considered as the best control measure. Proteins involved in host cell interaction and invasion, as well as antigens mediating inflammatory responses have been the most frequently assessed vaccine targets. However, despite considerable efforts no effective vaccine has been introduced to the market to date. The development of effective compounds to limit the effects of vertical transmission of N. caninum tachyzoites has emerged as an alternative or addition to vaccination, provided suitable targets and safe and efficacious drugs can be identified. Additionally, the combination of both treatment strategies might be interesting to further increase protectivity against N. caninum infections and to decrease the duration of treatment and the risk of potential drug resistance. Well-established and standardized animal infection models are key factors for the evaluation of promising vaccine and compound candidates. The vast majority of experimental animal experiments concerning neosporosis have been performed in mice, although in recent years the numbers of experimental studies in cattle and sheep have increased. In this review, we discuss the recent findings concerning the progress in drug and vaccine development against N. caninum infections in mice and ruminants.

Diagnóstico molecular de infecção por Ehrlichia canis e Babesia vogeli e diagnóstico sorológico de infecção por Neospora caninum e Toxoplasma gondii em cães provenientes do município de Cândido Sales-BA e microrregião

ABSTRACT The occurrence of Toxoplasma gondii, Neospora caninum, Ehrlichia canis and Babesia vogeli in dogs from the municipality of Cândido Sales, Bahia, was investigated. Total and peripheral blood samples were obtained from 131 dogs. Blood smears were performed to check for morulae. Toxoplasma gondii and N. caninum infections were determined by an Indirect Immunofluorescence Reaction. Nested-PCR and PCR were used for the diagnoses of E. canis and B. vogeli infections, respectively. Additionally, the risk factors associated with infection by these agents were analyzed. The frequency of infection was 70.2% for N. caninum, 67.9% for T. gondii and 37.4% for E. canis. None of the dogs tested positive for B. vogeli. Morulae of Ehrlichia spp. were identified in two animals and the piroplasm in one animal. Age (> 3 years) was considered a risk factor for infections by E. canis and N. caninum and the rural habitat for infections by N. caninum. Co-infections were frequent, mainly with N. caninum and T. gondii (45.03% of dogs). Ehrlichia canis infection was significantly associated with N. caninum and T. gondii infection. These findings indicated a high occurrence of T. gondii, N. caninum, and E. canis in the studied region.

Dynamics of ex vivo cytokine transcription during experimental Toxocara canis infection in Balb/c mice.

The cytokine microenvironment is crucial in generating and polarizing the immune response. A means of monitoring this environment would be of great value for better understanding Toxocara canis immune modulation. The aim of this study was to analyze the dynamics of cytokine transcription ex vivo, during early (24-48 hours) and late (15-30 days) times post-infection, in the mesenteric lymph nodes, spleen and intestinal mucosa of Balb/c mice experimentally infected with T. canis larvae. Mice in the treated group were infected with 100 third-stage larvae (L3), whereas mice in the control group were not infected. Analyses were performed at different times: 24-48 hours post-infection (HPI), 15-30 days post-infection (DPI). IL4, IL10, IL12 and Ym1 mRNA transcriptions were analyzed through qPCR. This study showed cytokine transcription mediated by migrating larvae in the mesenteric lymph nodes and spleen at 24-48 HPI, whereas cytokine transcription in the intestinal mucosa was observed only at late times (15-30 DPI). These results suggest that the T. canis larvae migration during infection might play a role in cytokine dynamics. Since the cytokine microenvironment is crucial in modulating immune response, knowledge of cytokine dynamics during T. canis infections pave the way to better understand its interaction with the host.

Trypanosoma evansi em cães de Barão de Melgaço, Mato Grosso: prevalência molecular

ABSTRACT: Trypanosoma evansi, the hemoflagellate pathogen that causes “surra,” is a protozoan that infects the widest variety of mammals worldwide, primarily horses, camels, dogs, and wild animals. Cases of canine trypanosomiasis caused by T.evansi have been reported in the Brazilian pantonal region. This study determined the prevalence of T.evansi and investigate risk factors. The study used blood samples from dogs in the municipality of Barão de Melgaço in the pantonal of the state of Mato Grosso, Brazil. The owner was given a structured epidemiological questionnaire containing information about the risk factors. The quantitative polymerase chain reaction technique was used to detect T.evansi DNA using species-specific oligonucleotides TevF and TevR of the gene encoding a 227-bp portion of the glycoprotein of the variant surface (VSG) T.evansi Rode Trypanozoon (RoTat) 1.2. Two (prevalence of 0.5%) genetic materials of T.evansi were reported in the403 samples. Although, no risk factor was associated with infection (P > 0.05), proximity to vegetation and streams, as well as the presence of tabanids, rodents, and marsupials, which are factors in the occurrence of infection, were observed in positive dogs, implying that the municipality of Barão de Melgaço has epidemiological characteristics that allow canine infection by T.evansi.

Exploring antibiotic resistance profiles in Escherichia coli strains isolated from canine wound infections: A comprehensive antibiogram analysis

Exploring antibiotic resistance profiles in Escherichia coli strains isolated from canine wound infections: A comprehensive antibiogram analysis

Characterization of biofilm-forming Escherichia coli in canine urinary tract infections: Phenotypic and genotypic insights

Characterization of biofilm-forming Escherichia coli in canine urinary tract infections: Phenotypic and genotypic insights

Epidemiological, and molecular investigation of Canine parvovirus-2 infection in Egypt.

Canine parvovirus enteritis (CPE) is a contagious viral disease of dogs caused by the canine parvovirus-2 (CPV-2) associated with high morbidity and mortality rates. CPV-2 has a high global evolutionary rate. Molecular characterization of CPV-2 and understanding its epidemiology are essential for controlling CPV-2 infections. This study examined the risk factors and survival outcomes of dogs infected with CPV-2. Molecular characterization of CPV-2 genotypes circulating in Egypt was performed to determine the evolution of CPV-2 nationally and globally. An age-matched case-control study was conducted on 47 control and 47 CPV-infected dogs. Conditional logistic regression analysis examined the association between the potential risk factors and CPE in dogs. Survival analysis was performed to determine the survival pattern of the infected dogs. Thirteen fecal samples from infected dogs were collected to confirm the CPV genotype by CPV-2 VP2 gene sequencing, assembly of nucleotide sequences, and phylogenic analysis. Unvaccinated and roamer dogs had eight and 2.3 times higher risks of CPV infection than vaccinated dogs and non-roamer dogs, respectively. The risk of death from CPE was high among dogs without routine visits to veterinary clinics and among non-roamer dogs. Molecular characterization of CPV-2 confirmed its genotype identity and relationship with the CPV-2 c and b clade types. This study highlights the potential factors for CPE control, especially vaccination and preventing dogs from roaming freely outside houses. Isolated CPV genotypes are closely related to southern Asian genotypes, suggesting a substantial opportunity for global transmission.

Importance of Biomarkers and Cytokines in the Prognosis of Canine Parvovirus Infection

Importance of Biomarkers and Cytokines in the Prognosis of Canine Parvovirus Infection

Estimation of latamoxef (moxalactam) dosage regimens against β-lactamase-producing Enterobacterales in dogs: a pharmacokinetic and pharmacodynamic analysis using Monte Carlo simulation.

One of the most significant research areas in veterinary medicine is the search for carbapenem substitutes for the treatment of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-E). This study applied a pharmacokinetic/pharmacodynamic (PK/PD) strategy in validating optimal latamoxef (LMX) therapeutic regimens against canine ESBL-E infections. Five dogs were administered a bolus dose of 40 mg/kg LMX intravenously to measure serum drug concentrations and determine PK indices using the noncompartmental model. The highest minimum inhibitory concentration (MIC) with a probability of target attainment ≥90% was used to compute the PK/PD cutoff values for bacteriostatic (time for which the unbound drug concentration was above the MIC [fTAM] ≥ 40%) and bactericidal (fTAM ≥ 70%) effects when administered at 20, 30, 50, and 60 mg/kg, in addition to 40 mg/kg. The cumulative fraction of response (CFR) was determined using the MIC distribution of wild-type ESBL-E in companion animals. The PK/PD cutoff values can be increased by reducing the dosing interval rather than increasing the dose per time. Based on the calculated CFRs for ESBL-producing Escherichia coli and Klebsiella pneumoniae, all LMX regimens in this study and those administered at 30-60 mg/kg every 8 and 6 hr were found to be optimal (CFR ≥ 90%) for exerting bacteriostatic and bactericidal effects, respectively. However, the regimens of 50 and 60 mg/kg every 6 hr may merely exert bacteriostatic effects on ESBL-producing Enterobacter cloacae. Further clinical trials are required to confirm the clinical efficacy of LMX.

Clinical variability of Toxocara canis infection in children

Toxocariasis maintains significant relevance at present. This study focuses on presenting the diversity of clinical symptoms and the specific clinical course of toxocariasis in children. Early diagnosis becomes crucial for initiating effective antiparasitic treatment, thereby contributing to reducing the risk of recurrence and chronicity of the condition.

Dirofilaria immitis in dogs from the coastal tourist region of the state of Alagoas, Brazil.

Canine dirofilariasis, caused by Dirofilaria immitis, is prevalent worldwide. However, the frequency of canine infection in the state of Alagoas, Brazil is scarcely unknown. This study aimed to evaluate the frequency of D. immitis infection in dogs from the coastal municipalities of Alagoas and analyze the risk factors associated with the infection. A cross-sectional study was performed using 426 dogs of different breeds and sex distributed across 15 coastal municipalities in the state of Alagoas. Blood samples were collected from each dog and analyzed for circulating microfilariae and free D. immitis antigens. To investigate the risk factors associated with D. immitis infection, we collected information on dog environments using an epidemiological questionnaire. The results revealed that 12.7% of dogs tested positive for D. immitis. Dogs with travel history were 3.52 times more likely to be infected. Thus, infected dogs in the coastal region of Alagoas should be regularly monitored and the public health system should plan strategies to control this zoonotic disease.

SEROLOGICAL SCREENING FOR Neospora caninum INFECTION IN A DAIRY CATTLE FARM WITH REPRODUCTIVE DISORDERS, IN SOUTH-EASTERN ROMANIA

Neospora caninum is an apicomplexan protozoa parasite that causes reproductive disorders in cattle worldwide. Despite the high seroprevalence reported in Romania, there are limited data on N. caninum infection in dairy cattle, and no studies have evaluated the presence of infection over time in a limited area. Therefore, this study aimed to assess the seroprevalence of N. caninum in a dairy cattle farm in Southeastern Romania where a previously study reported about the cattle exposure to N. caninum infection. A total of 85 cattle, assigned in four groups, according to the reproductive status (repeated breeding syndrome, history of abortion, pregnant cows, and fresh cows) were tested for the presence of N. caninum antibodies, using an indirect ELISA test. The overall seroprevalence was 28.23% (95% CI: 18.67–37.80). According to the reproductive groups, the seroprevalence varied between 19.04% (95% CI: 2.25-35.84) in fresh cows to 38.09% (95% CI: 17.32 - 58.87) in cows with repeated breeding syndrome. By these findings new information is provided about the disease's presence in the studied farm, implying that infection with N. caninum may be the primary cause of reported reproductive disorders, as well as about the infection's persistent nature.

A Current Update on Neospora caninum

Neospora caninum is an apicomplexan protozoan parasite, which was first identified as a cause of canine paralysis. This parasite is now recognized as an important cause of reproductive problems and abortion in cows. Prior to its first recognition in Norwegian dogs in 1984 and consequential classification as a distinct species in 1988, many N. caninum infections were misdiagnosed as toxoplasmosis. Neospora has a complex life cycle and transmission routes. Carnivores probably become infected by ingesting tissue cysts containing bradyzoites, and herbivores probably become infected by the ingestion of food or drinking water contaminated by N. caninum sporulated oocysts from the feces of carnivores. During pregnancy it becomes activated again, breaks out of the tissue cysts and migrates to the placenta. Infection of the placenta may lead to abortion, which would provide a source of contaminated meat for definitive hosts. In addition, the parasite may be transmitted to the foetus, which can lead to the birth of congenitally and persistently infected calves. Most reports of neosporosis outbreaks have occurred in cows that are intensively managed; thus, the incidence increases as larger cattle farms with intensive feeding practices become more common. Immunofluorescent antibody test (IFAT) and indirect enzyme-linked immunosorbent assay (ELISA) and histopathology of fetus are used for diagnosis. At present, there is no effective treatment for bovine neosporosis. Control of abortion in infected cattle depends on saving food and water sources and the grazing environment from feces of carnivores, properly discarding aborted feoutus and control of dog.

Sensitivity & Specificity of ELISA Kit for Antibody Detection of Canine Parvovirus and Canine Distemper Infection in Dogs

Sensitivity & Specificity of ELISA Kit for Antibody Detection of Canine Parvovirus and Canine Distemper Infection in Dogs

Serological and molecular detection of Toxoplasma gondii and Neospora caninum in free-ranging rats from Nagpur, India.

Toxoplasma gondii and Neospora caninum are cyst-forming coccidian parasites that infect both wild and domestic non-felids as intermediate hosts, with rodents serving as important reservoir hosts during their life cycles. This study was aimed at investigating T. gondii and N. caninum infections and identifying factors favouring T. gondii infection in free-ranging rats from India. A total of 181 rodents were trap-captured, and blood and brain samples were subsequently collected for serological and molecular examination of T. gondii and N. caninum. Antibodies against T. gondii and N. caninum were detected by MAT/NAT and IFAT in 13.8% (25/181) and 1.65% (3/181) of rodents, respectively. All three N. caninum samples positive by NAT/IFAT were also positive for ELISA, while for T. gondii, 19 of 25 MAT/IFAT positive samples were also positive for ELISA. The antibody titers (MAT/NAT/IFAT) of rodents seropositive for T. gondii ranged from 25 to 400, while those of rats seropositive for N. caninum ranged from 25 to 100. Also, using PCR, DNA from T. gondii (B1 gene) and N. caninum (NC5 gene) was found in 2.76% (5/181) of brain samples and 0.55% (1/181) of brain samples. All PCR positive samples were also seropositive. No mixed infections were observed in the serological and molecular detections. A Chi-square analysis revealed that older rats and rats living in urban areas are significantly associated with T. gondii infection; however, rodent species, gender, location, habitat types, and seasonality were statistically nonsignificant. Overall, this study demonstrated that T. gondii was widely distributed while N. caninum was less prevalent among free-ranging rats in the studied area.

Toxocara canis-induced changes in host intestinal microbial communities

BackgroundToxocara canis is a roundworm that resides in the gastrointestinal tract of dogs and causes various pathological changes. The dog’s intestinal system consists of a diverse and dynamic bacterial community that has extensive effects on intestinal physiology, immunity and metabolics. In the case of intestinal parasites, interactions with the host intestinal flora are inevitable during the process of parasitism.MethodsWe studied the role of T. canis in regulating the composition and diversity of the intestinal flora of the host by high-throughput sequencing of the 16S ribosomal RNA gene and various bioinformatics analyses.Results The α-diversity analysis showed that Toxocara canis infection resulted in a significant decrease in the abundance and diversity of host intestinal flora. The β-diversity analysis showed that the intestinal flora of infected dogs was similar to that carried by T. canis. Analysis of the microflora composition and differences at the phylum level showed that the ratio of Firmicutes to Bacteroidetes (F/B ratio) increased with T. canis infection. Analysis of species composition and differences at the genus level revealed that the proportion of some of the pathogenic bacteria, such as Clostridium sensu stricto and Staphylococcus, increased after T. canis infection.ConclusionsToxocara canis infection affected the composition and diversity of the flora in the host intestinal tract. These results not only shed light on the potential mechanism of T. canis invasion and long-term survival in the intestinal tract, but also provide a new basis for the development of anthelmintic drugs.Graphical

EPIDEMIOLOGY OF TOXOPLASMA GONDII AND NEOSPORA CANINUM INFECTION IN GOATS FROM AGUASCALIENTES, MEXICO.

The objective of this study was to describe the epidemiology of Toxoplasma gondii and Neospora caninum infection by estimating seroprevalence and its association with certain risk factors in goats from Aguascalientes, Mexico. A total of 150 blood samples was taken from 10 farms and serum samples were subjected to enzyme-linked immunosorbent assay indirect test to detect T. gondii and N. caninum antibodies; the association between seroprevalence and some potential risk factors was estimated through logistic regression analysis. The general seroprevalence for T. gondii was 12.6%, observed in the farms in a range of 6.6 to 60%, finding seropositive animals in 80% of them; for N. caninum the seroprevalence was 3.3% and in farms a range of 6.6 to 13.3% was identified and 30% of them had at least 1 seropositive animal. The coinfection was 0.66%. The risk analysis for T. gondii identified a history of abortions (odds ratio 9.25) as a factor associated with seroprevalence; for N. caninum, no risk factor was identified.

Exploring multiplex qPCR as a diagnostic tool for detecting microfilarial DNA in dogs infected with Dirofilaria immitis: A comparative analysis with the modified Knott’s test

Current recommendations to diagnose cardiopulmonary dirofilariosis in dogs caused by Dirofilaria immitis involves tandem antigen and circulating microfilariae tests. The modified Knott’s test is an important tool in heartworm diagnosis, allowing identification of circulating microfilariae. However, the subjective nature of the modified Knott’s test affects its accuracy and diagnostic laboratories usually do not provide a quantitative outcome. Quantitative enumeration of microfilariae enables clinicians to track treatment progress and acts as a proxy for detecting emerging macrocyclic lactone resistance. There is a need for better diagnostic tools suitable for routine use to efficiently and accurately quantify the presence of D. immitis microfilaremia. The aim of this study was to determine whether the quantitative modified Knott's test can be substituted by multiplex quantitative polymerase chain reaction (qPCR) targeting D. immitis and associated Wolbachia endosymbiont DNA in canine blood samples. To do this, genomic DNA samples (n = 161) from Australian dogs, collected as part of a previous 2021 study, were assessed in a TaqMan qPCR targeting DNA of D. immitis, Wolbachia sp. and Canis lupus familiaris. Of the 161 genomic DNA samples, eight were considered positive for D. immitis microfilariae. The qPCR assay demonstrated good efficiency (E = 90 to 110%, R2 > 0.94). Considering the performance and efficient use of bench time, this TaqMan qPCR assay is a suitable alternative to the modified Knott’s test for quantitative enumeration of microfilariae (Cohen’s kappa coefficient [κ]: κ = 1 using D. immitis qPCR marker, κ = 0.93 using Wolbachia qPCR marker). The qPCR data demonstrated a comparable result to that of the quantitative modified Knott’s test in a 2022 survey of D. immitis in Australian dogs (n = 23) before and after macrocyclic lactone (ML) administration. Improving the detection and diagnosis of canine heartworm infections will assist veterinarians in better managing and controlling disease outcomes and will be valuable for tracking the spread of ML resistance in Australia.

The Diverse Pathogenicity of Various Babesia Parasite Species That Infect Dogs.

Babesia species infect a very wide range of mammal hosts across the globe, and zoonotic infections are of growing concern. Several species of the Babesia genus infect dogs, and some of these cause significant morbidity and mortality. The Apicomplexan parasite resides within the red cell and infections result in direct damage to the host through intra- and extravascular hemolysis. An exuberant inflammatory response by the host to some species of Babesia parasites also results in significant collateral damage to the host. Canine infections have been the subject of many studies as the well-being of these companion animals is increasingly threatened by the spread of tick vectors and an increasingly mobile dog population. There are currently no widely available and effective vaccines, and effective treatment can be challenging. Understanding disease pathogenesis underlies the development of new treatments. The varying pathogenicity of the various Babesia parasite species that infect dogs offers an opportunity to explore the molecular basis for the wide range of diseases caused by infection with this parasite genus. In this review, we focus on what has been reported about the clinical presentation of Babesia-infected dogs in an attempt to compare the severity of disease caused by different Babesia species.

Biotechnological and virological analysis of canine parvovirus infections by C-reactive protein levels, serological, hematological and molecular techniques.

The study aims to approach Canine Parvovirus (CPV) diagnosis using multi-method biotechnological techniques including molecular, serological, and hematological analyses. CPVs are causing severe global viral diseases with high dog mortality. Samples were taken from 52 unvaccinated dogs exhibiting symptoms between 2020 and 2021. These included stool, blood, serum, and patient data. CPV genomic DNA was extracted from fresh stools, with DNA concentration and purity measured using Nano drop-spectrophotometry. CPV genomic DNA was detected via RT-PCR in 29 samples (55.8%), CPV IgM-Ab and IgG-Ab were detected in the sera through ELISA in 27 samples (51.9%), and Canine parvovirus antigens were identified in the stool samples by immunochromatography in 20 samples (38.5%). Utilizing canine-specific quantitative ELISA kits, the average level of serum C-reactive protein (CRP) was determined to be 4.66 g/L (with a range of 3.27 to 6.05 g/L). Hematological analysis revealed lymphopenia in 89.6%, leucopenia in 44.8%, anemia in 68.9%, and low hematocrit in 82.8%. All the dogs examined were under 1 year of age, among which 21 (72.4%) were up to 3 months old, and 8 (27.6%) were up to 6 months old, testing positive for CPV. The highest CPV positivity, at 93.1% (n=27), was observed among dogs with outdoor access. The results indicated that hematological parameters and CRP alone were not specific for CPV diagnosis, but provided valuable data for prognosis and differential diagnosis. No significant differences were observed in RT-PCR and ELISA results. However, a noticeable reduction in positivity rates was evident in lateral immunochromatographic viral antigen detection in stool.