Afzal Sajjid

Bio: Afzal Sajjid is an academic researcher. The author has contributed to research in topics: Dairy cattle & Seroprevalence. The author has an hindex of 1, co-authored 1 publications receiving 16 citations.

Effects of Age and Breed on the Prevalence of Neospora caninum in Commercial Dairy Cattle from Pakistan

Abstract: Neospora caninum is a major cause of bovine abortion worldwide. A serological survey was carried out to determine the seroprevalence of exposure to N. caninum in dairy cattle based on age and breed from Punjab and Sindh provinces, Pakistan. Serum samples from 641 animals from 12 herds from Punjab (n = 7) and Sindh (n = 5) provinces were tested for antibodies against N. caninum using a commercially available competitive enzyme-linked immunosorbent assay. Positive reactions to N. caninum were seen in 277 (43%) of the 641 of the samples. Seropositive animals were present in all 12 herds. Animals over 2 yr of age (47%) and crossbreds (55%) were more likely to be seropositive than the other cattle examined. These results indicate that N. caninum infection is widespread among dairy cattle in Pakistan.

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

Abstract: 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.

Neospora caninum versus Brucella spp. exposure among dairy cattle in Ethiopia: a case control study.

Abstract: This case-control study aimed at assessing the relative association of Neospora caninum and Brucella species exposure with reproductive disorders. The study was carried out between October 2011 and June 2012 on 731 dairy cows sampled from 150 dairy farms in selected 17 conurbations of Ethiopia. Two hundred sixty-six of the cows were categorized as cases based on their history of abortion or stillbirth while the remaining 465 were controls. The presence of antibody to N. caninum was screened using indirect ELISA, while Brucella spp. exposure was assayed serially using Rose Bengal Plate Test and Complement Fixation Test. Exposure to N. caninum was more frequently observed among cases (23.8 %) than controls (12.7 %), while no significant difference (p > 0.05) was noted for Brucella exposure between the two groups. Moreover, the proportion of cows with disorders like retention of fetal membrane, endometritis and increased inter-calving period were significantly higher (p < 0.05) among Neospora seropositive cows. In conclusion, the finding discloses the strong association of N. caninum with reproductive disorders compared to Brucella spp. exposure. However, neither N. caninum nor Brucella spp. could explain the majority (73.2 %) of the reported abortions and stillbirths in cattle. Hence, this observation underscores the need for more intensive investigation on the identification of causes of the aforementioned disorders in dairy cattle of Ethiopia.

Seroprevalence and risk factors assessment of the three main infectious agents associated with abortion in dairy cattle in Isfahan province, Iran

Abstract: This study aimed to determine the seroprevalence and identify the risk factors associated with Neospora caninum, Bovine herpesvirus type 1 (BHV-1), and Bovine viral diarrhea virus (BVDV) infection on industrial Holstein dairy cattle farms in Isfahan province, Central Iran. Blood samples were taken from 216 apparently healthy cattle from 16 randomly selected Holstein dairy farms in the North, South, East, and West of Isfahan in the summer of 2017. The antibodies to N. caninum, BHV-1, and BVDV were detected using a commercially available ELISA kit. The overall seroprevalence for N. caninum, BHV-1, and BVDV was 19%, 72.2%, and 52.8%, respectively. The significant major risk factors of BHV-1 in cattle were identified as farm direction, age groups, parity, and milk yield by the univariate analysis (p < 0.05). The significant major risk factors of BVDV in cattle were identified as age groups, parity, milk yield, and stage of pregnancy (p < 0.05). The only significant major risk factor of N. caninum was farm direction (p < 0.05). A significant association of concurrent infection with BVDV and BHV-1 has shown in the current study (p < 0.05). This study is the first to report the risk factors for N. caninum, BHV-1, and BVDV infection in the central part of Iran and allows us to conclude that these agents are widely distributed in this region.

The Sero-epidemiology of Neospora caninum in Cattle in Northern Tanzania.

Abstract: Neospora caninum is a protozoan intracellular parasite of animals with a global distribution. Dogs act as definitive hosts, with infection in cattle leading to reproductive losses. Neosporosis can be a major source of income loss for livestock keepers, but its impacts in sub-Saharan Africa are mostly unknown. This study aimed to estimate the seroprevalence and identify risk factors for N. caninum infection in cattle in northern Tanzania, and to link herd-level exposure to reproductive losses. Serum samples from 3,015 cattle were collected from 380 households in 20 villages between February and December 2016. Questionnaire data were collected from 360 of these households. Household coordinates were used to extract satellite derived environmental data from open-access sources. Sera were tested for the presence of N. caninum antibodies using an indirect ELISA. Risk factors for individual-level seropositivity were identified with logistic regression using Bayesian model averaging (BMA). The relationship between herd-level seroprevalence and abortion rates was assessed using negative binomial regression. The seroprevalence of N. caninum exposure after adjustment for diagnostic test performance was 21.5% [95% Credibility Interval (CrI) 17.9–25.4]. The most important predictors of seropositivity selected by BMA were age greater than 18 months [Odds ratio (OR) = 2.17, 95% CrI 1.45–3.26], the local cattle population density (OR = 0.69, 95% CrI 0.41–1.00), household use of restricted grazing (OR = 0.72, 95% CrI 0.25–1.16), and an increasing percentage cover of shrub or forest land in the environment surrounding a household (OR = 1.37, 1.00–2.14). There was a positive relationship between herd-level N. caninum seroprevalence and the reported within-herd abortion rate (Incidence Rate Ratio = 1.03, 95% CrI 1.00–1.06). Our findings suggest N. caninum is likely to be an important cause of abortion in cattle in Tanzania. Management practices, such as restricted grazing, are likely to reduce the risk of infection and suggest contamination of communal grazing areas may be important for transmission. Evidence for a relationship between livestock seropositivity and shrub and forest habitats raises questions about a potential role for wildlife in the epidemiology of N. caninum in Tanzania.