Seroprevalence of Neospora caninum Antibodies in Cattle in Veracruz, Mexico

Meta-analysis of the prevalence and risk factors associated with bovine neosporosis

Neospora caninum is one of the main infectious agents that cause reproductive disorders in cattle. However, knowledge about the prevalence and causal factors of bovine neosporosis is needed in order to establish control measures. The purpose of this study was to estimate the pooled prevalence and determine the risk factors of bovine neosporosis using meta-analytic methods. Searches for data on N. caninum seroprevalence and potential risk factors were conducted in the PubMed, LILACS, and SciElo databases. The random effects model was used for the meta-analysis of the included studies. The pooled prevalence of N. caninum in cattle was 24% (95% confidence interval (CI), 19-29) in North and Central America, 24% (95% CI, 20-28) in South America, 18% (95% CI, 14-21) in Asia, 15% (95% CI, 12-18) in Europe, 13% (95% CI, 11-16) in Africa, and 8% (95% CI, 4-14) in Oceania. A significant correlation was found between N. caninum infection and abortion in cows (odds ratio (OR) = 2.66, 95% CI, 1.97-3.59). The following risk factors were signicantly associated with N. caninum seroprevalence: presence of dogs on the farm (OR = 2.84; 95% CI, 1.40-5.80) and the type of cattle production system, with dairy cattle being more susceptible to bovine neosporosis (OR = 1.60; 95% CI, 1.16-2.19) than beef cattle. The adoption of measures to prevent the dissemination of N. caninum in cattle herds is suggested, aiming to reduce the economic losses incurred to the dairy and beef industry.

Seroprevalence of Neospora caninum and associated risk factors in intensive or semi-intensively managed dairy and breeding cattle of Ethiopia

A cross-sectional study of Neospora caninum infection was conducted in major milksheds of Ethiopia. Cattle (n=2334) from 273 farms were bled and the sera screened for antibodies against N. caninum using a commercial ELISA kit. Herd and individual animal level data were collected from farm records and a semi-structured questionnaire format. The overall animal level seroprevalence was 13.3%, while the prevalence at farm level was 39.6%. In urban and peri-urban smallholder dairy farms, the seroprevalence was 14.9%, while 12.9% and 9.8% reactors were found among commercial dairy farms and breeding cattle, respectively. At farm level, 35.7% of urban and peri-urban farms, 47.5% of the commercial farms and five of the breeding farms were found to have at least one infected animal. Purchased cows (OR: 2.3) and cows with history of maternal reproductive disorders (OR: 2.1) were associated with seropositivity at the individual animal level. Crossbred cattle (Holstein-Friesian crossed with indigenous zebu) were associated with lower risk than pure breeds (OR: 0.6). A trend of prevalence increment was observed for large herd sizes (OR: 1.8). Other factors that were associated with seropositivity were: presence of farm dogs for more than 5 years (OR: 1.9), access to farm by wild carnivores (OR: 3.1) and compromised farm hygienic status (OR: 3.4). Abortion, retention of foetal membrane and metritis were the most frequently reported clinical reproductive disorders among seropositive cattle. Together, these finding indicate that N. caninum infection is highly prevalent, widely distributed and clinically important in dairy and breeding cattle of Ethiopia. N. caninum should be considered an important infectious cause of reproductive disorders in Ethiopian cattle, and the risk factors for exposure identified here should be used as basis for implementing control measures that could limit the transmission of this infection.

Reproductive disorders in relation to Neospora caninum, Brucella spp. and bovine viral diarrhoea virus serostatus in breeding and dairy farms of central and southern Ethiopia

Abortion and stillbirth are important reproductive disorders in the dairy industry and are often caused by infectious agents. This study investigated whether bovine viral diarrhoea virus (BVDV), Brucella spp., and Neospora caninum are associated with abortion and/or stillbirth in dairy cattle in Ethiopia. Dairy cattle from 99 farms were categorized as cases (n = 134) or controls (n = 268) according to reproductive data. Blood samples were screened for antibodies for these infectious agents. The overall proportion of cattle that were seropositive for BVDV, Brucella spp., and N. caninum was 11·7%, 3·2%, and 17·2%, respectively. Seropositivity for BVDV and Brucella spp. was similar for cases and controls, but significantly more cases were seropositive for N. caninum (29·8%) than controls (10·8%). This is the first report demonstrating N. caninum is common in dairy cattle in Ethiopia, and is probably a greater impediment to reproductive success in Ethiopian dairy farms than either BVDV or Brucella spp.

Prevalence of Neospora caninum antibodies in dairy cattle and water buffaloes and associated abortions in the plateau of Southern Peninsular India

A seroprevalence study of bovine neosporosis was conducted among 1,927 dairy cattle and 341 water buffaloes from Karnataka and Andhra Pradesh states in plateau of southern peninsular India by employing competitive enzyme-linked immunosorbent assay. Overall, 12.61 and 9.97 % sera samples were found positive for the presence of Neospora caninum antibody, respectively, among cattle and water buffaloes. Out of 1,927 sera samples from cattle, 912 and 1,015 samples were collected from unorganized and organized herds, respectively. The cattle screened were of upgraded Holstein-Friesian and water buffaloes were of graded Surti breed. Significantly (p < 0.05) higher prevalence was found in the cattle in unorganized herds (16.66 %) in comparison to organized herds (8.96 %). The highest seroprevalence was recorded in the age group of 4 years and above in both type of cattle herds and water buffaloes. There was a significant variation of seroprevalence (p < 0.05) observed between different age groups of cattle. The rate of seroprevalence increased with the increment in the age of the animals suggesting a possibility of horizontal mode of transmission of the infection from the environment. The percentage of abortion history was more in seropositive group (51.65 %) in comparison to the seronegative group (5.84 %) and the seropositive cattle were 8.84 times more likely to experience abortion than the seronegative cattle. The occurrence of abortion among different age groups varied significantly (p < 0.05). The findings revealed the presence of neosporosis in the southern peninsular India among cattle and water buffaloes and a strong association between the seroprevalence and abortion.

First report of Neospora caninum infection in cattle in Sudan

A cross-sectional survey was conducted in Sudan to determine sero-prevalence and risk factors associated with Neospora caninum infection in non-vaccinated dairy herds and to assess importance of the disease. Blood samples were collected from a total of 262 animals from 25 herds. Sera were tested for antibodies against N. caninum using ELISA test. The prevalence rates of N. caninum antibodies in cattle were high both at herd level (44%) and at individual animal level (10.7%). Herd level infection rates were similar in Khartoum State (43.7%) and at Gazira States (44.4%). The overall prevalence rates were higher (16.1%) in Gazira State than in Khartoum State (9%) but with no significant variation. The sero-prevalence at individual animal level was significantly higher (p < 0.05) in animals with history of abortion (12.8%) than in apparently healthy animal (11.3%), animal with history of infertility (8.1%), or neonatal death of calves (4.3%). In addition, significantly higher (P < 0.05) sero-prevalence was observed in samples collected during the rainy season (6.87%) than winter (3.05%) or summer (0.76%). However, no significant differences in sero-prevalence due to locality, animal breed, sex, and age were observed (p > 0.05). This preliminary study reveals for the first time the existence of natural N. caninum infection in Sudan. Also, the findings of the present study indicated that this disease is highly prevalent in two major areas of dairy production in the country, and this calls for control strategy to be implemented.