Characterization of an Outbred Pregnant Mouse Model of Neospora caninum Infection

Quinn, Helen; Miller, Catherine M.; Ryce, Cheryl; Windsor, Peter; Ellis, John

doi:10.2307/3285344

Cited by 13 publications

(34 citation statements)

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“…The isolates with the highest (100%) parasite DNA detection rates (Nc-Bahia and Nc-Liv) also produced the most severe clinical signs and the highest vertical transmission and pup mortality rates. The results for Nc-Liv (100% parasite detection, transmission and pup mortality) were consistent with the results of previous studies (Quinn et al 2002;Regidor-Cerrillo et al 2010). These observations suggest that, similar to bovine isolates, the more virulent isolates can spread more widely and achieve higher parasite burdens in infected mouse brains, leading to more severe lesions .…”

Section: Discussionsupporting

confidence: 93%

Clinical outcome and vertical transmission variability among canine Neospora caninum isolates in a pregnant mouse model of infection

et al. 2013

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We compared the clinical outcome and vertical transmission of six canine Neospora caninum isolates using a pregnant BALB/c model. Four of the isolates were obtained from oocysts of naturally infected dogs (Nc-Ger2, Nc-Ger3, Nc-Ger6 and Nc-6Arg) and two were from diseased dogs with neurological signs (Nc-Bahia and Nc-Liv). The dams were inoculated with 2×106 tachyzoites of each isolate at day 7 of pregnancy. Morbidity, mortality and the antibody responses were evaluated in both the dams and the offspring, as was parasite transmission to the progeny. The mortality rates varied from 100% in Nc-Bahia and Nc-Liv-infected pups to 19% or less for those infected with the isolates from oocysts. The vertical transmission rates varied from 9 to 53% for N. caninum from oocysts, compared with 100% for the Nc-Liv and Nc-Bahia isolates. All dams showed specific IgG responses against tachyzoite and rNc-GRA7 antigens, confirming Neospora infection. The highest IgG levels were detected in mice inoculated with the Nc-Liv and Nc-Bahia isolates. These results demonstrate marked differences in virulence between the N. caninum isolates obtained from oocysts and neurologically affected dogs. This variability could help us to explain the differences in the outcome of the infection in definitive and intermediate hosts.

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Section: Discussionsupporting

confidence: 93%

Clinical outcome and vertical transmission variability among canine Neospora caninum isolates in a pregnant mouse model of infection

et al. 2013

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“…A subsequent paper reported a mortality rate of 70 % in Balb/c mice within 41 days of an s.c. challenge with 5r10 5 NC1 strain tachyzoites (Lindsay et al 1999). in Balb/c mice infected with NC Liverpool strain N. caninum parasites (Quinn et al 2002). Symptoms of clinical neosporosis in mice include a rough coat, depressed appetite, dehydration, weight loss, tottering gait and reluctance to move (Lindsay and Dubey, 1989).…”

Section: Discussionmentioning

confidence: 99%

Long-term passage of tachyzoites in tissue culture can attenuate virulence ofNeospora caninum in vivo

et al. 2006

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To determine whether prolonged in vitro passage would result in attenuation of virulence in vivo, Neospora caninum tachyzoites were passaged for different lengths of time in vitro and compared for their ability to cause disease in mice. Groups of Balb/c mice were inoculated intraperitoneally with 5 x 10(6) or 1 x 10(7) of low-passage or high-passage N. caninum tachyzoites. The mice were monitored for changes in their demeanour and body weight, and were culled when severe clinical symptoms of murine neosporosis were observed. Mice inoculated with the high-passage parasites survived longer (P<0.05), and showed fewer clinical symptoms of murine neosporosis, compared to the mice receiving the low-passage parasites. The parasite was detected in the brains of inoculated mice using immunohistochemistry and ITS1 PCR. Tissue cysts containing parasites were seen in mice inoculated with both low-passage and high-passage parasites. When the in vitro growth rates of the parasites were compared, the high-passage parasites initially multiplied more rapidly (P<0.001) than the low-passage parasites, suggesting that the high-passage parasites had become more adapted to tissue culture. These results would suggest that it is possible to attenuate the virulence of N. caninum tachyzoites in mice through prolonged in vitro passage.

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“…Mouse inoculation was used as a tool to characterize and compare the virulence of the parasite isolates (Atkinson et al 1999;Quinn et al 2002). However, different strains of mice vary in their behavior to N. caninum infection; out-bred mice are resistant to neosporosis (Dubey and Lindsay 1996) while inbred strains are only moderate to acute neosporosis (Ramamoorthy et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Characterization of tissue distribution and histopathological lesions in Neospora caninum experimentally infected gerbils

et al. 2009

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Gerbils (Meriones unguiculatus) were inoculated intraperitoneally (i.p.) with Neospora caninum tachyzoites to examine parasite distribution and histological lesions at different time points over a 9-day period of infection. Gerbils were sacrificed 12 h post-infection (PI), then daily intervals up to day 9 PI. The parasite was detected by PCR assay targeting the Nc5 sequence of N. caninum. The parasite was not found in any organs until day 5 PI, however, from day 8 PI onwards, they were detected in all the organs examined as demonstrated by PCR. The first target organs in acute N. caninum infection were liver, spleen, and kidney, but not the blood as was expected. Histologic lesions were detected in the liver and spleen only, no lesions were found in other organs examined until the end of the experiment. Notably, the focal miliary hepatitis was observed in the liver of infected gerbils just after 1 day post-inoculation, whereas splenic lesions were not found until day 5 PI. These results reinforce the applicability of gerbils as a suitable model of acute neosporosis and provide new insights into the response of gerbils to N. caninum intraperitoneal infection.

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Characterization of an Outbred Pregnant Mouse Model of Neospora caninum Infection

Cited by 13 publications

References 0 publications

Clinical outcome and vertical transmission variability among canine Neospora caninum isolates in a pregnant mouse model of infection

Clinical outcome and vertical transmission variability among canine Neospora caninum isolates in a pregnant mouse model of infection

Long-term passage of tachyzoites in tissue culture can attenuate virulence ofNeospora caninum in vivo

Characterization of tissue distribution and histopathological lesions in Neospora caninum experimentally infected gerbils

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