Neospora caninum as causative agent of bovine encephalitis in Brazil

Abstract

<jats:p>For supporting the Brazilian bovine encephalitis surveillance program this study examined the differential diagnosis of Neospora caninum in central nervous system (CNS) by histological analysis (HE staining), immunohistochemistry (IHC), and nested-PCR using a set of primers from the Nc5 region of the genomic DNA and ITS1 region of the ribosomal DNA. A sample of 302 cattle presenting neurological syndrome and negative for rabies, aged 0 to 18 years, from herds in 10 Brazilian states was evaluated for N. caninum from January 2007 to April 2010. All specimens tested negative with IHC and nested-PCR using primers from the ITS1 region of ribosomal DNA, while two positive cases (0.66%) were found using primers from the Nc5 region of genomic DNA: a 20 month-old male and a 72 month-old female, both from São Paulo State. Only the male presented severe multifocal necrotizing encephalitis associated with mononuclear cell infiltration, a pathognomonic lesion caused by parasites of the family Sarcocystidae, and only this case was associated with N. caninum thus representing 0.33% positivity. Future studies should explore the association of IHC and nested-PCR with real-time PCR, a quantitative method that could be standardized for improving the detection of N. caninum in bovine CNS specimens.</jats:p>

Lesions and distribution of Neospora caninum in tissues of naturally infected female goats

“…Lymphoplasmacytic myocarditis and myositis, lymphoplasmacytic perivascular cuffing and foci of gliosis, all of which suggest protozoan infection, were found in the goats, but PCR was more efficient for detecting N. caninum in tissues than IHC, with 47.8% PCRpositive samples. These results are consistent with those described in adult animals, whose definitive diagnosis was only possible by isolating the agent in cell culture or by PCR (Sawada et al, 2000;Koyama et al, 2001;Bishop et al, 2010;Malaguti et al, 2012;Suteu et al, 2013).…”

“…Some studies showed that N. caninum does not produce tissue cysts efficiently (Weiss et al, 1999;Vonlaufen et al, 2004;Goodswen et al, 2013) in naturally infected animals or in experimental models such as rats and gerbils (Weiss et al, 1999;Vonlaufen et al, 2004;Goodswen et al, 2013). It is possible that the parasite induces chronic infection in adult animals or that adult animals could be subclinical hosts that are immunologically protected, thereby hindering the occurrence of lesions and cyst formation (Malaguti et al, 2012).…”

Effects of Neospora caninum on reproductive performance and the efficacy of treatment with a combination of sulphadiazine-trimethoprim and toltrazuril: a longitudinal field study

“…Encephalomyelitis was the predominant type of lesion in the neonatal calves. Other symptoms included flexion or hyperextension of the hind limbs and forelimbs, ataxia, decreased patellar reflex, exophthalmia or asymmetry in the eyes, scoliosis, hydrocephalus, and narrowing of the spinal cord (Dubey et al , 2007Innes, 2007;Malaguti et al 2012). Four neonatal calves from seropositive cows had neurological symptoms, such as exophthalmia, ataxia, and lack of coordination.…”

“…It has been reported that 12-42% of aborted foetuses are infected with N. caninum and that this protozoan is one of the most important abortion agents in cows worldwide (Dubey 1999(Dubey , 2003Jenkins et al 2002;Hall et al 2005;Dubey et al 2007;Piagentini et al 2012;Xu et al 2012). In addition to abortions, N. caninum causes foetal viability disorders, neurological symptoms in newborns (Lassen et al 2012;Malaguti et al 2012), an inability to grow, low average birth weight (Dubey and Schares 2011) and decreases in milk production (Tiwari et al 2007), and reproductive performance (VanLeeuwen et al 2010b). It has also been reported that N. caninuminfected cows require more inseminations per pregnancy, have a longer time of open days, and have a higher culling rate than seronegative cows (Hall et al 2005;Tiwari et al 2005;Kamga-Waladjo et al 2010).…”

Neospora caninum, A potential cause of reproductive failure in dairy cows from Northern Greece

“…The abortions can occur starting with month three of gestation until delivery (Dubey et al, 2013;Reiterová et al, 2009;Dubey et al, 2007) in an epidemic or endemic manner (Wouda et al, 1999). N. caninum can also cause fetal viability disorders or neurological birth defects in newborn calves (Lassen et al, 2012;Malaguti et al, 2012) and those younger than 2 months of age (Dubey, 2003). The N. caninum-infected young calves may present neurologic signs, low birth weight (Dubey and Schares, 2011), difficulties to rise and stand, flexed or hyperextended hind and/or forelimbs, and in some cases exophthalmia or asymmetrical appearance of the eyes.…”