Neospora caninum (Protozoa: Apicomplexa) infections in rats

1990 ◽  
Vol 68 (7) ◽  
pp. 1595-1599 ◽  
Author(s):  
David S. Lindsay ◽  
J. P. Dubey

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.

Parasitology ◽  
2020 ◽  
pp. 1-14
Author(s):  
Jana Ježková ◽  
Jitka Prediger ◽  
Nikola Holubová ◽  
Bohumil Sak ◽  
Roman Konečný ◽  
...  

Abstract The diversity and biology of Cryptosporidium that is specific for rats (Rattus spp.) are not well studied. We examined the occurrence and genetic diversity of Cryptosporidium spp. in wild brown rats (Rattus norvegicus) by microscopy and polymerase chain reaction (PCR)/sequencing targeting the small subunit rDNA (SSU), actin and HSP70 genes. Out of 343 faecal samples tested, none were positive by microscopy and 55 were positive by PCR. Sequence analysis of SSU gene revealed the presence of Cryptosporidium muris (n = 4), C. andersoni (n = 3), C. ryanae (n = 1), C. occultus (n = 3), Cryptosporidium rat genotype I (n = 23), Cryptosporidium rat genotype IV (n = 16) and novel Cryptosporidium rat genotype V (n = 5). Spherical oocysts of Cryptosporidium rat genotype I obtained from naturally-infected rats, measuring 4.4–5.4 μm × 4.3–5.1 μm, were infectious to the laboratory rats, but not to the BALB/c mice (Mus musculus) nor Mongolian gerbils (Meriones unguiculatus). The prepatent period was 3 days post infection and the patent period was longer than 30 days. Naturally- and experimentally-infected rats showed no clinical signs of disease. Percentage of nucleotide similarities at the SSU, actin, HSP70 loci between C. ratti n. sp. and the rat derived C. occultus and Cryptosporidium rat genotype II, III, IV, and V ranged from 91.0 to 98.1%. These genetic variations were similar or greater than that observed between closely related species, i.e. C. parvum and C. erinacei (93.2–99.5%). Our morphological, genetic and biological data support the establishment of Cryptosporidium rat genotype I as a new species, Cryptosporidium ratti n. sp.


2019 ◽  
Vol 202 ◽  
pp. 1-6 ◽  
Author(s):  
Luiz Daniel de Barros ◽  
Alessandra Taroda ◽  
Ana Carolina Miura ◽  
Ana Flávia Minutti ◽  
João Pedro Sasse ◽  
...  

2020 ◽  
Vol 72 (5) ◽  
pp. 1719-1726
Author(s):  
G. Toscan ◽  
A.S. Cezar ◽  
P. Bräunig ◽  
G.R. Pereira ◽  
A.C. Vargas ◽  
...  

ABSTRACT Neospora caninum is the main etiologic agent of neosporosis in domestic animals and its pathogenesis comprises two characteristic phases: acute and chronic. Rodents are used as experimental models to mimic acute and chronic bovine neosporosis. In this study, we inoculated a total of 27 female gerbils, with different doses of N. caninum tachyzoites aiming to induce chronic disease. DNA was extracted from different organs of each animal after spontaneous death or euthanasia. Encephalic tissues were submitted to a highly sensitive real time PCR aiming to detect chronically infected animals. All the other samples were submitted to standard PCR. A total of 11 gerbils died due to acute neosporosis, as confirmed by N. caninum DNA detection in organs. 5x103 tachyzoites/mL of N. caninum was the dosage of antigen that can induce chronic infection in gerbils. In the encephalon sections of some animals that showed clinical signs of persistent infection, we found 70% positive for the anterior encephalon section, suggesting this area as preferential for cyst formation. Therefore, we determined the doses of tachyzoites that cause acute or chronic infection and detection of positive tissues, preferably, systemic organs during acute and encephalon in chronic phases.


2021 ◽  
pp. 104063872199668
Author(s):  
Waléria Borges-Silva ◽  
Mariana M. Rezende-Gondim ◽  
Gideão S. Galvão ◽  
Daniele S. Rocha ◽  
George R. Albuquerque ◽  
...  

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.


2013 ◽  
Vol 44 (1) ◽  
pp. 60 ◽  
Author(s):  
Germán J Cantón ◽  
Frank Katzer ◽  
Julio Benavides-Silván ◽  
Stephen W Maley ◽  
Javier Palarea-Albaladejo ◽  
...  

Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 531 ◽  
Author(s):  
Eliane Dallegrave ◽  
Eliane Taschetto ◽  
Mirna Bainy Leal ◽  
Flavia Techera Antunes ◽  
Marcus Gomez ◽  
...  

Phα1β, a purified peptide from the venom of the spider Phoneutria nigriventer, and its recombinant form CTK 01512-2 are voltage-dependent calcium channel (CaV) blockers of types N, R, P/Q, and L with a preference for type N. These peptides show analgesic action in different pain models in rats. The aim of this study was to evaluate the acute intrathecal toxicity of the native and recombinant Phα1β toxin in Wistar rats. Clinical signs, serum biochemistry, organ weight, and histopathological alterations were evaluated in male and/or female rats. Dyspnea was observed in males, hyporesponsiveness in females, and Straub tail and tremors in both genders. There were no significant differences in male organ weight, although significant differences in the female relative weight of the adrenal glands and spleen have been observed; these values are within the normal range. Serum biochemical data revealed a significant reduction within the physiological limits of species related to urea, ALT, AST, and FA. Hepatic and renal congestion were observed for toxin groups. In renal tissue, glomerular infiltrates were observed with increased glomerular space. These histological alterations were presented in focal areas and in mild degree. Therefore, Phα1β and CTK 01512-2 presented a good safety profile with transient toxicity clinical signals in doses higher than used to obtain the analgesic effect.


2018 ◽  
Vol 7 (5) ◽  
pp. 412-418
Author(s):  
Mohd Urooj ◽  
◽  
Mohammad Ahmed Khan ◽  
G. Thejaswini ◽  
Munawwar Husain Kazmi ◽  
...  

Jawarish Shahi (JS) is a compound polyherbal Unani pharmacopoeial formulation indicated for Khafqan (Palpitation), Nafkh-e-Shikam (Flatulence) and Waswas (Insanity; false perception and hallucinations). Jawarish Shahi contains herbs like Halela (Terminalia chebula), Amla (Emblica officinalis), Kishneez (Coriandrum sativum), Elaichi Khurd, (Elettaria cardamomum), and Bed Mushk (Salix caprea). The present study was carried out as per OECD 408 guidance to evaluate 90 days repeated oral dose toxicity in male and female Sprague Dawley rats. The study was performed at dose levels 1028 and 2000 mg/kg bw. No adverse effects were reported with respect to body weight, feed intake, behavior and clinical signs indicative of systemic toxicity. The expected growth pattern was observed in body weight and feed intake as compared to control group at both dose levels in male and female rats. There were few significant alterations with respect to hematology, and clinical biochemistry, however the results were within normal range thus considered toxicologically insignificant. The microscopic examination of different organ/tissue showed that no histopathological changes were observed. The findings of the study showed that No Observed Adverse Effect Level (NOAEL) for JS is greater than 2000 mg/kg body weight


2015 ◽  
pp. 4455-4460
Author(s):  
Alexandre A. Tonin ◽  
Aleksandro S. Da Silva ◽  
Victor C. Pimentel ◽  
Daniele Zanini ◽  
Maria Rosa C. Schetinger ◽  
...  

Objective. This study aimed to investigate the presence and activity of the ecto adenosine deaminase (E-ADA) enzyme in tachyzoites of Neospora caninum (Nc-1 strain), as well as to assess the activity of a well-known E-ADA inhibitor, the deoxycoformycin. Materials and methods. The parasites were grown in cell culture, being subsequently separated in a pellet of tachyzoites, on which the E-ADA activity was tested using the concentrations 0 (control), 0.2, 0.4 and 0.8 mg mL-1. Results. The E-ADA showed high activity, progressively increasing its activity according to the enhancement of the protein concentration. The test was carried out with different concentrations of deoxycoformycin, showing that it was able to inhibit the E-ADA present on the free form of the parasite. Conclusions. Based on these results we conclude that the E-ADA is present on tachyzoites of N. caninum, and deoxycoformycin is able to inhibit this enzyme. In this sense, knowing the negative impact of N. caninum on reproductive issue in cattle (mainly abortion), might it is an alternative in order to deal with this parasitic infection.Key words: adenosine deaminase, deoxycoformycin, neosporosis (Source: CAB, MeSH).


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