Pathogenic characterization in mice of Neospora caninum isolates obtained from asymptomatic calves

Parasitology ◽  
2010 ◽  
Vol 137 (7) ◽  
pp. 1057-1068 ◽  
Author(s):  
D. PEREIRA GARCÍA-MELO ◽  
J. REGIDOR-CERRILLO ◽  
E. COLLANTES-FERNÁNDEZ ◽  
A. AGUADO-MARTÍNEZ ◽  
I. DEL POZO ◽  
...  
Keyword(s):  
Mouse Model ◽  
Neospora Caninum ◽  
Late Phase ◽  
Clinical Signs ◽  
Parasite Burden ◽  
Brain Lesions ◽  
Organ Distribution ◽  
Igg2a Isotype ◽  
Species Variability ◽  
Igg2a Response

SUMMARYIn this study, we characterized 8 new isolates obtained from healthy but congenitally infected calves using a BALB/c mouse model. Neospora caninum-infected mice survived without exhibiting any clinical signs of disease. Nevertheless, differences among isolates in parasite organ distribution, parasite burden and the severity of histopathological lesions were determined. Mice infected with the Nc-Spain 5H, Nc-Spain 7 and Nc-Spain 9 isolates showed higher parasite burdens and more severe brain lesions during the late phase of infection compared to mice infected with the Nc-Spain 2H, Nc-Spain 3H or Nc-Spain 6 isolates. Furthermore, differences in the immunoglobulin IgG1 and IgG2a isotype kinetics induced by these isolates were observed, with a more rapid IgG2a response seen in mice infected with the Nc-Spain 2H and Nc-Spain 3H isolates. These results confirm the intra-species variability of N. caninum pathogenicity.

Vaccination of mice against experimental Neospora caninum infection using NcSAG1- and NcSRS2-based recombinant antigens and DNA vaccines

Parasitology ◽  
2003 ◽  
Vol 126 (4) ◽  
pp. 303-312 ◽  
Author(s):  
A. CANNAS ◽  
A. NAGULESWARAN ◽  
N. MÜLLER ◽  
S. EPERON ◽  
B. GOTTSTEIN ◽  
...  
Keyword(s):  
Protective Effect ◽  
Neospora Caninum ◽  
Clinical Signs ◽  
Parasite Burden ◽  
Positive Control ◽  
Recombinant Antigen ◽  
Eukaryotic Expression ◽  
Caninum Infection ◽  
Recombinant Antigens ◽  
Specific Pcr

NcSAG1 and NcSRS2, the two major immunodominant tachyzoite surface antigens of the apicomplexan parasite Neospora caninum, were investigated for their potential as vaccine candidates in mice. Recombinant recNcSRS2 and recNcSAG1 were expressed in Escherichia coli as poly-histidine-tagged fusion proteins. Separate groups of mice were immunized with purified recNcSAG1, recNcSRS2, or a combination of both, and were then challenged with N. caninum tachyzoites. Subsequent experiments included intramuscular vaccination of mice with the eukaryotic expression plasmid pcDNA3 containing either NcSRS2 or NcSAG1 cDNA inserts, followed by a single booster with the corresponding recombinant antigens. Immunization with a crude somatic antigen (NC1-extract) was included in the experiments. Following challenge, the presence of the parasite in the different organs was assessed by a N. caninum-specific PCR, while the parasite burden in infected brain tissue was assessed by quantitative real-time PCR. Immunization of mice employing individual recombinant antigens, or combined recNcSAG1/recNcSRS2, resulted in a lower degree of protection against cerebral infection, when compared to combined DNA/recombinant antigen vaccination. Serological analysis showed that this protective effect was associated with the occurrence of antibodies directed against native parasite antigens in those animals receiving combined DNA/recombinant antigen vaccination. Conversely, mice immunized with recombinant antigens alone generated antibodies recognizing only the recombinant antigens. Mice experiencing clinical signs such as walking disorders, rounded back, apathy and paralysis were observed only in the untreated positive control groups, but never in the vaccinated groups. Our results suggest that a combined DNA/recombinant antigen-vaccine, based on NcSAG1 and NcSRS2, respectively, exhibited a highly significant protective effect against experimentally induced cerebral neosporosis in mice.

Cytologic detection of Toxoplasma gondii in the cerebrospinal fluid of a dog and in vitro isolation of a unique mouse-virulent recombinant strain

2021 ◽  
pp. 104063872199668
Author(s):  
Waléria Borges-Silva ◽  
Mariana M. Rezende-Gondim ◽  
Gideão S. Galvão ◽  
Daniele S. Rocha ◽  
George R. Albuquerque ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Toxoplasma Gondii ◽  
Recombinant Strain ◽  
Neospora Caninum ◽  
Clinical Signs ◽  
Species Identity ◽  
Cytologic Examination ◽  
Pcr Rflp ◽  
Tissue Homogenates

Parasites resembling Neospora caninum or Toxoplasma gondii were detected by cytologic examination of cerebrospinal fluid (CSF) from a dog with neurologic disease. The dog became severely ill and was euthanized. Canine tissue homogenates were used for direct parasite isolation in cell culture, bioassay in 2 mouse lineages, and PCR. T. gondii was isolated in monkey kidney cells, and species identity was confirmed by PCR. Inoculated parasites were highly virulent for mice, which developed clinical signs and were euthanized immediately. PCR-RFLP for T. gondii using the cultured isolate (TgDgBA22) was conducted with 12 genetic markers, and a unique recombinant strain was identified. Detection of T. gondii by CSF cytology, although described in humans, had not been reported previously in dogs, to our knowledge, and was crucial for the diagnosis of toxoplasmosis in the examined dog.

scholarly journals Neospora caninuminfection in birds: experimental infections in chicken and embryonated eggs

Parasitology ◽  
2007 ◽  
Vol 134 (14) ◽  
pp. 1931-1939 ◽  
Author(s):  
P. I. FURUTA ◽  
T. W. P. MINEO ◽  
A. O. T. CARRASCO ◽  
G. S. GODOY ◽  
A. A. PINTO ◽  
...  
Keyword(s):  
Laying Hens ◽  
Neospora Caninum ◽  
Parasite Burden ◽  
Asymptomatic Infection ◽  
Igg Antibodies ◽  
Intermediate Hosts ◽  
Susceptibility To Infection ◽  
Experimental Infections ◽  
Inoculum Dose ◽  
Specific Igg

SUMMARYNeospora caninumcauses economical impact in cattle-raising farms since it is implicated as the major cause of bovine abortions. Although infection by the parasite has been widely described in mammals, the role of birds in its life-cycle is still obscure. Therefore, this work aimed to evaluate the infection byN. caninumin different chicken models. Experimental infections were conducted in 7-day-old chicks, laying hens and embryonated eggs, where samples were analysed for parasite burden, IgG antibodies and lesions promoted. Chickens demonstrated an asymptomatic infection, although with seroconversion and systemic replication of the parasite. In laying hens, no signs of vertical transmission were observed. However, embryonated eggs inoculated by the allantoic cavity route demonstrated susceptibility to infection, with mortality rates around 50% independent of the inoculum dose. Additionally, dogs became infected after ingestion of different amounts of inoculated eggs, producing either oocysts or specific IgG antibodies. The results herein presented demonstrate that chickens may be intermediate hosts ofN. caninumand that embryonated eggs could be a useful model to study the parasite's biology.

Neospora caninum (Protozoa: Apicomplexa) infections in rats

1990 ◽  
Vol 68 (7) ◽  
pp. 1595-1599 ◽  
Author(s):  
David S. Lindsay ◽  
J. P. Dubey
Keyword(s):  
Rattus Norvegicus ◽  
Neospora Caninum ◽  
Clinical Signs ◽  
Hepatic Necrosis ◽  
Female Rats ◽  
Methylprednisolone Acetate ◽  
Laboratory Rats ◽  
Experimental Inoculation ◽  
Caninum Tachyzoites ◽  
Subcutaneous Inoculation

The susceptibility of laboratory rats (Rattus norvegicus) to experimental inoculation with tachyzoites of Neospora caninum was examined. Groups of female rats were intramuscularly injected with 0, 2, or 4 mg of methylprednisolone acetate (MPA) 7 days prior to, and on the day of, subcutaneous inoculation with 0 or 1.5 × 105 tachyzoites. Clinical signs of disease or deaths did not occur in rats given nothing or only N. caninum tachyzoites. Rats given only 4 mg MPA failed to grow as well as rats given nothing or only N. caninum tachyzoites but were otherwise healthy. All of 20 rats given 4 mg MPA and tachyzoites died of hepatitis and pneumonia within 12 days postinoculation. Hepatic necrosis was the most striking lesion seen in these rats, and other milder lesions consisted of pneumonia, encephalitis, and myositis. The response of rats given 2 mg MPA and tachyzoites was less severe. Three of 20 rats died with encephalitis, myositis, hepatitis, and pancreatitis. Mild lesions, but no N. caninum tachyzoites, were seen in 3 of 14 rats inoculated only with tachyzoites. Rats given the 4 mg MPA treatment and inoculated with N. caninum tachyzoites appear to be suitable subjects for examining acute neosporosis and could be used in studies designed to examine treatment of acute disease.

Susceptibility of Common Family Anatidae Bird Species to Clade 2.3.4.4e H5N6 High Pathogenicity Avian Influenza Virus: An Experimental Infection Study

2021 ◽  
Author(s):  
Kosuke Soda ◽  
Yukiko Tomioka ◽  
Chiharu Hidaka ◽  
Mayu Matsushita ◽  
Tatsufumi Usui ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Late Phase ◽  
Clinical Signs ◽  
Bird Species ◽  
Oral Route ◽  
Post Inoculation ◽  
Infectious Dose ◽  
Epidemic Season ◽  
Source Of Infection ◽  
High Pathogenicity

Abstract Background: There were large outbreaks of high pathogenicity avian influenza (HPAI) caused by clade 2.3.4.4e H5N6 viruses in the winter of 2016–2017 in Japan, which caused large numbers of deaths among several endangered bird species including cranes, raptors, and birds in Family Anatidae. In this study, susceptibility of common Anatidae to a clade 2.3.4.4e H5N6 HPAI virus was assessed to evaluate their potential to be a source of infection for other birds. Eurasian wigeons (Mareca penelope), mallards (Anas platyrhynchos), and Northern pintails (Anas acuta) were intranasally inoculated with 106, 104, or 102 50% egg infectious dose (EID50) of clade 2.3.4.4e A/teal/Tottori/1/2016 (H5N6). Results: All birds survived for 10 days without showing any clinical signs of infection. Most ducks inoculated with ≥104 EID50 of virus seroconverted within 10 days post-inoculation (dpi). Virus was mainly shed via the oral route for a maximum of 10 days, followed by cloacal route in late phase of infection. Virus remained in the pancreas of some ducks at 10 dpi. Viremia was observed in some ducks euthanized at 3 dpi, and ≤106.3 EID50 of virus was recovered from systemic tissues and swab samples including eyeballs and conjunctival swabs. Conclusions: These results indicate that the subject duck species have a potential to be a source of infection of clade 2.3.4.4e HPAI virus to the environment and other birds sharing their habitats. Captive ducks should be reared under isolated or separated circumstances during the HPAI epidemic season to prevent infection and further viral dissemination.

scholarly journals A Listeria monocytogenes-Based Vaccine Formulation Reduces Vertical Transmission and Leads to Enhanced Pup Survival in a Pregnant Neosporosis Mouse Model

Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1400
Author(s):  
Dennis Imhof ◽  
William Robert Pownall ◽  
Camille Monney ◽  
Anna Oevermann ◽  
Andrew Hemphill
Keyword(s):  
Listeria Monocytogenes ◽  
Mouse Model ◽  
Neospora Caninum ◽  
Post Partum ◽  
Systemic Infection ◽  
Surface Protein ◽  
Control Group ◽  
Protective Effects ◽  
Igg Antibody ◽  
Th2 Response

The apicomplexan parasite Neospora caninum is the worldwide leading cause of abortion and stillbirth in cattle. An attenuated mutant Listeria monocytogenes strain (Lm3Dx) was engineered by deleting the virulence genes actA, inlA, and inlB in order to avoid systemic infection and to target the vector to antigen-presenting cells (APCs). Insertion of sag1, coding for the major surface protein NcSAG1 of N. caninum, yielded the vaccine strain Lm3Dx_NcSAG1. The efficacy of Lm3Dx_NcSAG1 was assessed by inoculating 1 × 105, 1 × 106, or 1 × 107 CFU of Lm3Dx_NcSAG1 into female BALB/c mice by intramuscular injection three times at two-week intervals, and subsequent challenge with 1 × 105N. caninum tachyzoites of the highly virulent NcSpain-7 strain on day 7 of pregnancy. Dose-dependent protective effects were seen, with a postnatal offspring survival rate of 67% in the group treated with 1 × 107 CFU of Lm3Dx_NcSAG1 compared to 5% survival in the non-vaccinated control group. At euthanasia (25 days post-partum), IgG antibody titers were significantly decreased in the groups receiving the two higher doses and cytokines recall responses in splenocyte culture supernatants (IFN-γ, IL-4, and IL-10) were increased in the vaccinated groups. Thus, Lm3Dx_NcSAG1 induces immune-protective effects associated with a balanced Th1/Th2 response in a pregnant neosporosis mouse model and should be further assessed in ruminant models.

scholarly journals Identification of the Genome Segments of Bluetongue Virus Type 26/Type 1 Reassortants Influencing Horizontal Transmission in a Mouse Model

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2208
Author(s):  
Houssam Attoui ◽  
Baptiste Monsion ◽  
Bernard Klonjkowski ◽  
Stéphan Zientara ◽  
Peter P. C. Mertens ◽  
...  
Keyword(s):  
Mouse Model ◽  
Bluetongue Virus ◽  
Reverse Genetics ◽  
Horizontal Transmission ◽  
Clinical Signs ◽  
Small Ruminants ◽  
Minor Role ◽  
Individual Genome ◽  
A Minor ◽  
Reassortant Viruses

Bluetongue virus serotypes 1 to 24 are transmitted primarily by infected Culicoides midges, in which they also replicate. However, “atypical” BTV serotypes (BTV-25, -26, -27 and -28) have recently been identified that do not infect and replicate in adult Culicoides, or a Culicoides derived cell line (KC cells). These atypical viruses are transmitted horizontally by direct contact between infected and susceptible hosts (primarily small ruminants) causing only mild clinical signs, although the exact transmission mechanisms involved have yet to be determined. We used reverse genetics to generate a strain of BTV-1 (BTV-1 RGC7) which is less virulent, infecting IFNAR(−/−) mice without killing them. Reassortant viruses were also engineered, using the BTV-1 RGC7 genetic backbone, containing individual genome segments derived from BTV-26. These reassortant viruses were used to explore the genetic control of horizontal transmission (HT) in the IFNAR(−/−) mouse model. Previous studies showed that genome segments 1, 2 and 3 restrict infection of Culicoides cells, along with a minor role for segment 7. The current study demonstrates that genome segments 2, 5 and 10 of BTV-26 (coding for proteins VP2, NS1 and NS3/NS3a/NS5, respectively) are individually sufficient to promote HT.

scholarly journals Immediate Interferon Gamma Induction Determines Murine Host Compatibility Differences between Toxoplasma gondii and Neospora caninum

2020 ◽  
Vol 88 (4) ◽  
Author(s):  
Rachel S. Coombs ◽  
Matthew L. Blank ◽  
Elizabeth D. English ◽  
Yaw Adomako-Ankomah ◽  
Ifeanyi-Chukwu Samuel Urama ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Immune Responses ◽  
Interferon Gamma ◽  
Neospora Caninum ◽  
Ectopic Expression ◽  
Parasite Burden ◽  
Interleukin 12 ◽  
Content Type ◽  
Ifn Γ ◽  
And Control

ABSTRACT Rodents are critical for the transmission of Toxoplasma gondii to the definitive feline host via predation, and this relationship has been extensively studied as a model for immune responses to parasites. Neospora caninum is a closely related coccidian parasite of ruminants and canines but is not naturally transmitted by rodents. We compared mouse innate immune responses to N. caninum and T. gondii and found marked differences in cytokine levels and parasite growth kinetics during the first 24 h postinfection (hpi). N. caninum-infected mice produced significantly higher levels of interleukin-12 (IL-12) and interferon gamma (IFN-γ) by as early as 4 hpi, but the level of IFN-γ was significantly lower or undetectable in T. gondii-infected mice during the first 24 hpi. “Immediate” IFN-γ and IL-12p40 production was not detected in MyD88−/− mice. However, unlike IL-12p40−/− and IFN-γ−/− mice, MyD88−/− mice survived N. caninum infections at the dose used in this study. Serial measures of parasite burden showed that MyD88−/− mice were more susceptible to N. caninum infections than wild-type (WT) mice, and control of parasite burdens correlated with a pulse of serum IFN-γ at 3 to 4 days postinfection in the absence of detectable IL-12. Immediate IFN-γ was partially dependent on the T. gondii mouse profilin receptor Toll-like receptor 11 (TLR11), but the ectopic expression of N. caninum profilin in T. gondii had no impact on early IFN-γ production or parasite proliferation. Our data indicate that T. gondii is capable of evading host detection during the first hours after infection, while N. caninum is not, and this is likely due to the early MyD88-dependent recognition of ligands other than profilin.

scholarly journals Review of idiopathic eosinophilic meningitis in dogs and cats, with a detailed description of two recent cases in dogs : review and clinical communication

2008 ◽  
Vol 79 (4) ◽  
Author(s):  
J.H. Williams ◽  
L.S. Koster ◽  
V. Naidoo ◽  
L. Odendaal ◽  
A. Van Veenhuysen ◽  
...  
Keyword(s):  
White Matter ◽  
Immunohistochemical Staining ◽  
Nervous Tissue ◽  
Mononuclear Cells ◽  
Age Of Onset ◽  
Neospora Caninum ◽  
Clinical Signs ◽  
Post Mortem ◽  
Central Nervous Tissue ◽  
Eosinophilic Meningoencephalitis

Eosinophilic meningoencephalitis (EME) has been described in various species of animals and in humans. In dogs it has been associated with protozoal infections, cuterebral myiasis and various other aetiologies. Ten cases of idiopathic eosinophilic meningoencephalitis have been reported in dogs and one in a cat where the origin was uncertain or unknown. The dogs were all males, of various breeds but with a predominance of Golden Retrievers and Rottweilers; they generally had a young age of onset. Two cases with no apparent underlying aetiology were diagnosed on post mortem examination. The 18-month-old, male Boerboel presented with sudden onset of cerebellar ataxia, as well as various asymmetrical cranial nerve deficits of 2 weeks' duration and without progression. Haematology revealed a peripheral eosinophilia. Necropsy showed extreme generalised congestion especially of the meninges and blood smear and histological sections of various tissues showed intravascular erythrocyte fragmentation with the formation of microcytes. Histopathology revealed severe diffuse cerebrocortical subarachnoidal meningitis and submeningeal encephalitis, the exudate containing variable numbers of eosinophils together with neutrophils and mononuclear cells. There was also deeper white matter and hippocampal multifocal perivascular mononuclear encephalitis and multifocal periventricular malacia, gliosis and phagocytosis of white matter. The cerebellum, brain stem and spinal cord showed only mild multifocal oedema or scattered occasional axon and myelin degeneration respectively, with no inflammation. Immunohistochemical staining of central nervous tissue for Toxoplasma gondii failed to show any antigen in the central nervous tissue. Ultrastructure of a single submeningeal suspected parasitic cyst showed it to be chromatin clumping within a neuron nucleus indicating karyorrhexis. Gram stain provided no evidence of an aetiological agent. The 3-year-old Beagle bitch had a Caesarian section after developing a non-responsive inertia 8 days prior to presentation. This animal's clinical signs included status epilepticus seizures unrelated to hypocalcaemia and warranted induction of a barbiturate coma. She died 4 hours later. Post mortem and histopathological findings in the brain were almost identical to those of the Boerboel and she also showed histological evidence of recent active intravascular haemolysis with microcyte formation. Rabies, distemper and Neospora caninum immunohistochemical stains were negative in the brains of both dogs. Immunohistochemical staining of the cerebral and meningeal exudates of the Beagle for T- and B-lymphocyte (CD3 and CD79a) markers showed a predominance of T-lymphocytes with fewer scattered B lymphocytes. A possible allergic response to amoxicillin / clavulanate is considered, as this appeared to be the only feature common to the recent history of both animals. An overview of EME in humans, dogs and cats is given and the previously published cases of idiopathic EME in dogs and the single published cat case are briefly reviewed.

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