The role of sheep in the epidemiology of Bovine alphaherpesvirus 1 (BoHV-1).

Bovine alphaherpesvirus 1 (BoHV-1) as a cusative agent for some diseases in cattle infects sheep and goat; and it is believed that these animals may be reservoir host for this virus. Thus, BoHV-1 infection in sheep and goat should be considerd when there is a program for control and eradication of this virus in cattle. Therefore, the aim of this study was to determine the seroprevalence of BoHV-1 in sheep, relationship between host and environmental factors with infection, and the role of sheep in the epidemiology of the BoHV-1. Blood samples were randomly collected from 310 healthy sheep in 6 cities of Khuzestan province (Southwest of Iran) including Ahvaz, Hendijan, Shushtar, Dezful, Masjed Soleyman and Behbahan. Sera were analyzed by virus neutralisation (VN) test for detection antibodies to BoHV-1. According to VN test, apparent and true seroprevalence seroprevalence of BoHV-1 infection was 28.4 % (95%CI: 23.4-33.4%) and 28.4 % (95%CI: 23.3-33.4%), respectively. Logistic regression revealed that the odds of infection between the age was 1.06 (95%CI: 0.9-1.25) (P > 0.05), implying that the odds of infection increased 6 % with rising one year of age. Besides, the relative frequency of infection in males was more than females', and the odds of infection in male sheep was identified to be 1.13 (95%CI: 0.47-2.71) (P > 0.05), compared to that in females. Moreover, in comparison to sheep with no history of abortion, the odds of infection in sheep with a history of abortion was 1.28 (95%CI: 0.57-2.87) (P > 0.05). The seroprevalence in Shushtar, Masjed Soleyman, Dezful, Ahvaz, Hendijan, and Behbahan were found to be 48.3, 46.7, 31.7, 20, 16.7, and 12 percent, respectively and 13.1 of fluctuation in infection can be justified by different geographical locations investigated in this study (P < 0.001). Considering the significant seroprevalence of BoHV-1, present study confirmed the role of sheep in the epidemiology of this virus and control of BoHV-1 in sheep should be considered by animal health authorities in areas where BoHV-1 is prevalent.

Development of a new method based on unmodified gold nanoparticles and peptide nucleic acids for detecting bovine viral diarrhea virus-RNA.

A simple colorimetric assay is presented for detecting bovine viral diarrhea virus (BVDV)-RNA based on aggregation of gold nanoparticles (AuNPs) in the presence of charge-neutral peptide nucleic acids (PNA). Free charge-neutral PNA oligomers tended to be adsorbed onto AuNPs and act as a coagulant, whereas hybridizing complementary RNA with PNA disrupted PNA-induced AuNP aggregation, and the NPs remained stable. However, non-complementary RNA did not have this effect, and PNA induced aggregation of the AuNPs that resulted in a color change of the reaction from red to blue. The label-free colorimetric assay developed was estimated to have a 10.48 ng/reaction BVDV-RNA detection limit for the visual assay and 1.05 ng/reaction BVDV-RNA using a spectrophotometer. Diagnostic sensitivity and specificity for the assay was in accordance with real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and nested RT-PCR results were 98 and 100%, respectively. Absorption of the 520/620 nm ratio was linear, along with an increase in the target RNA concentration of 1.64-52.4 ng/reaction (R2 = 0.992), which showed a linear correlation for the quantitative assay. This study established a rapid visual label and enzyme-free diagnostic assay for detecting BVDV that is applicable in any clinical laboratory.

Seroprevalence of Bluetongue in sheep in Kohgiluyeh and Boyer-Ahmad province, Iran.

Bluetongue (BT) is a viral disease of ruminants transmitted by Culicoides biting midges and has the ability to spread rapidly over large distances. The disease occurs almost worldwide between latitudes approximately 35˚ S and 50˚ N. Among the numerous diseases of ruminants, BT has gained considerable importance in recent years as one of the best examples of the effects of climate change on disease spread. Sheep are major livestock species in Iran, but studies of BT have not gained the priority compared to other diseases. Thus, the objective of this study was to describe the distribution and seroprevalence of bluetongue virus (BTV) infections in sheep in Kohgiluyeh and Boyer-Ahmad province of Iran, and to identify factors associated with the exposure of these sheep to BTV infection. Sera from 262 apparently healthy sheep were collected during the year 2011. The collected sera of the animals were screened with competitive enzyme like immunosorbent assay (c-ELISA). Two hundred and three (77.48%) out of 262 sera tested were positive to BTV antibodies. Statistically significant differences were found in the seroprevalence BT, between sex and age of sheep (p < 0.001). No statistically significant differences were observed in BTV seroprevalence among different seasons, nor among recently aborted and normally delivered.