Factors associated with seroprevalence of Neospora caninum in dairy cattle in southeastern Brazil

Abstract

Neosporosis is an infectious disease caused by Neospora caninum, an obligate intracellular cyst-forming protozoan considered a major cause of miscarriage in dairy cattle in many parts of the world. This cross-sectional study evaluated the relationship between reproductive abnormalities and seropositivity to N. caninum in 1,204 dairy cows from 40 farms located in the state of Minas Gerais, southeastern Brazil. Producers were interviewed, and blood samples were collected to perform indirect immunofluorescence tests (IFAT 1:200). Association between reproductive abnormalities and seropositivity in cattle was evaluated with generalized estimating equations. The true herd-level seroprevalence of N. caninum was 95 % (83.3-99.1), while the individual-level true seroprevalence was 21.6 % (19.2-24.2). Several reproductive abnormalities were significantly associated with seropositivity to N. caninum: occurrence of repeated estrus (p=0.02; OR=3.84; 95 % CI=1.239-11.893), repeated miscarriages (p=0.001; OR=2.54; 95 % CI=1.423-5.402), and temporary anestrus (p=0.001; OR=3.44; 95 % CI=1.976-5.994). Furthermore, loose dogs (p=0.041; OR=2.20; 95 % CI=1.033-4.672) when fed raw meat (p=0.001; OR=1.91; 95 % CI=1.443-2.519) are risk factors for N. caninum infection. We observed that seropositivity to N. caninum in cattle increases risk of miscarriage by almost twice throughout the reproductive life of cows (p=0.004; OR=1.978; 95 % CI=1.249-3.131). Serologic evidence in this study indicates that N. caninum infection is widely distributed among dairy herds and significantly associated with reproductive disorders, especially miscarriage, repeated estrus, and temporary anestrus.

Seroprevalence and risk factors associated with Neospora caninum in crossbred dairy cows in Uberlândia

“…This reinforces the importance of other risk factors such as individual repeated breeding, which increased the risk 5.9 fold in this study. This clinical sign was associated with the seroprevalence of N. caninum, as was previously described in dairy cattle from southeastern Brazil (BRUHN et al, 2013). Dogs were constantly present on the properties, and could be infected due to the ingestion of tissue containing bradyzoites (DUBEY et al, 2007).…”

“…Poor quality of water, the presence of dogs, poor hygiene conditions, and a history of abortions have already been reported as risk factors (GHALMI et al, 2012;SUN et al, 2015). In Brazil, the type of herd, method of herd management, presence of definitive hosts (SARTOR et al, 2005), and reproductive problems such as repeated breeding, history of abortion, and anestrus (BRUHN et al, 2013) have been reported as risk factors. Abortion is considered the main clinical manifestation of cows infected with N. caninum (HUSSIEN et al, 2012).…”

Infection by Neospora caninum in dairy cattle belonging to family farmers in the northern region of Brazil

“…There was a significant association between seropositivity for N. caninum and occurrences of abortions among dairy cows, thus reinforcing the role of N. caninum as a major cause of reproductive disorders (DUBEY et al, 2006;BRUHN et al, 2013;GHALMI et al, 2012). It is important to note that the reproductive problems described on 36 farms (57.14%) were occurrences of abortions, while on 26 (41.26%), they consisted of birth of weak calves, among which some evolving to death.…”

Toxoplasma gondii, Neospora caninum and Leishmania spp. serology and Leishmania spp. PCR in dogs from Pirassununga, SP

“…Some studies have found an increased prevalence of antibodies against N. caninum in dogs from rural areas, suggesting a greater exposure to horizontal transmission from contact with aborted fetuses and fetal membranes (BRUHN et al, 2013;NOGUEIRA et al, 2013). However, De Sousa et al (2012) obtained a seroprevalence of 4.2%, with half of the dogs' population from urban areas and half from rural areas with no significant difference observed between the groups.…”