Evaluation of Toxoplasma gondii and Neospora caninum infections in sheep from Uberlândia, Minas Gerais State, Brazil, by different serological methods

Abstract

Toxoplasmosis and neosporosis have been recognized as economically important diseases with considerable impact on the livestock industry. Considering the scarce information on the occurrence of Toxoplasma gondii and Neospora caninum infections in sheep from Uberlândia, Minas Gerais State, Brazil, this study aimed to investigate the frequency of antibodies against these parasites in sheep sera from this region by using different serological methods. A total of 155 sheep serum samples were analyzed by the indirect fluorescence antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) for the detection of IgG against T. gondii and N. caninum. Seroreactivity by IFAT showed 80% of samples with titers between 512 and 2048 for T. gondii (cutoff ≥ 64) and 78% presenting titers between 50 and 200 for N. caninum (cutoff ≥ 50). Seroreactivity by ELISA showed 75% of samples with ELISA index (EI) between 2.0 and 3.0 for T. gondii (cutoff ≥ 1.3) and 54% presenting EI between 1.3 and 2.0 for N. caninum (cut off ≥ 1.3). Discordant results by both tests were analyzed by immunoblot, resulting in a total seropositivity of 61% for T. gondii and 23% for N. caninum, with 41% to T. gondii only, 3% to N. caninum only, and 20% to both parasites. There was a significant positive association between seropositivity to T. gondii and age over one year (P<0.001), but such association was not found for N. caninum infection. In conclusion, as T. gondii and N. caninum infections are simultaneously present in sheep flocks of this region, it should be emphasized the importance to carry out a regular monitoring of Toxoplasma infection due to its high prevalence, its zoonotic potential and induction of reproductive disorders leading to economic losses. For neosporosis, sheep farmers should be instructed about the presence of the parasite in the flock, its risk factors and potential abortifacient role in sheep. Differential flock management could be valuable tool to establish the association of serological positivity and reproductive disease induced by N. caninum in sheep.

Neospora caninum seroprevalence and risk factors for ewes from Santa Catarina Plateau, Brazil

“…The prevalence of N. caninum infection observed in this study (7%) was similar to results from other surveys conducted in Brazil (FIGLIUOLO et al, 2004;ROMANELLI et al, 2007;UENO et al, 2009;SALABERRY et al, 2010;MUNHOZ et al, 2010;FARIA et al, 2010;MACHADO et al, 2011;ANDRADE et al, 2012) and in other countries, such as China (HUI, 2008), Czech Republic (BARTOVA et al, 2009 and Spain (PANADERO et al, 2010), with reported seropositivity rates for N. caninum ranging from 8.0 to 13.91% in the sheep samples analyzed using ELISA or IFAT. An association between the prevalence of N. caninum and crossbreed animals (P=0.0249) was observed.…”

“…In these properties, animal management is more appropriate, reducing the contact with sources of N. caninum infection. However, Salaberry et al (2010) found no correlation between breed and N. caninum infection and Nasir et al (2012), on the contrary, found higher infection prevalence in purebred animals. ¹ Relationship between the total number of positive animals per variable and the total number of animals from each variable.…”

“…In 39 (42.4%) of the 92 properties assessed at least one animal was positive for N. caninum (Table 1), with prevalence rates ranging from zero to 40%, which shows the widespread occurrence of coccidiosis among animals at the Plateau of Santa Catarina. AlMajali et al (2008), Aguiar et al (2004), Figliuolo et al (2004), Soares et al (2009), Faria et al (2010 and Salaberry et al (2010) found 45.8%, 60%, 86.6%, 17.1%, 53.8% and 83.3% of the properties with animals that tested positive for N. caninum, respectively.…”

Prevalence and risk factors associated with anti-Toxoplasma gondii antibodies in sheep from Bahia state, Brazil

“…Risk factors such as age, contact with cats, breeding system, and water supply can be highlighted and have been previously identified in ovine toxoplasmosis in Brazil (ROMANELLI et al, 2007;PINHEIRO et al, 2009;LOPES et al, 2010;ROSSI et al, 2011). Considering the importance of toxoplasmosis and the lack of epidemiological information in the state of Bahia, the aims of this study were to determine the prevalence of T. gondii infection in sheep flocks from southern Bahia state and identify possible risk factors associated with the infection.…”

Occurrences of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from four districts of Tocantins state, Brazilian Legal Amazon Region

“…Although comparison of frequencies of infection between regions are difficult, differences could be due to sampling methods employed herein. Rossi et al (2011), in a study of neosporosis using different serological methods, suggest that variations among frequencies rate may also be due to differential environment contamination and climatic conditions. Indeed, regions that present high annual rainfall index, such as Rondônia state, present higher occurrence rate for N. caninum.…”