A study on neonatal calf diarrhea induced by rotavirus

This review summarizes the results of a study on rotaviruses isolated from calves affected by neonatal diarrhea.

The results indicated that rotavirus infection is widespread and supported the evidence for an etiologic role of these viruses in neonatal diarrhea. Differences in virulence among bovine rotaviruses appeared also to be confirmed.

Conventionally reared calves were fully susceptible to the experimental infection induced by rotaviruses originating from heterologous hosts, i.e. monkeys, pigs and rabbits.

When rotavirus strains of bovine, simian and rabbit origin were compared by cross neutralization tests, it was found the simian and porcine strains were indistinguishable and both appeared to relate antigenically to the bovine strain.

Finally, it was proven that feeding newborn calves with colostrum and first milk of their dams, previously vaccinated with an inactivated adjuvanted rotavirus vaccine, could prevent the neonatal diarrhea from occurring.     

Detection of rotavirus in faecal specimens with a monoclonal antibody enzyme-linked immunosorbent assay: Comparison with polyclonal antibody enzyme immuno-assays and a latex agglutination test

Monoclonal antibodies have been produced against the 81/36F strain of rotavirus. One of them, was chosen as diagnostic reagent: it showed high ELISA reactivity with all the bovine, human and porcine rotavirus strains tested and reacted with VP6, structural protein product known to support the common rotavirus antigen.

A sandwich ELISA procedure using the chosen monoclonal as “capture and detecting” antibody was performed to detect rotavirus in faecal samples from experimentally inoculated newborn calves: it always gave a negative response with meconium and a positive response for the stool specimens which rotavirus have been isolated. This assay was compared with Enzygnost and Slidex Rota Kit tests and with a non-commercial sandwich ELISA test using polyclonal antibodies: it showed more sensitivity than the agglutination test and was as sensitive as the other two tests to detect rotavirus in routine diagnostic material. The test evaluated showed no equivocal results.     

Serotypes of Escherichia coli strains isolated from piglets with diarrhea in swine industrial farms

Serotypes of E. coli strains isolated from piglets, which died with symptoms of diarrhea in 9 swine industrial farms, were determined. Large numbers of serotypes (from 16 to 27) in individual farms were detected. The sets of serotypes from 9 investigated farms differed among each other significantly, depending on the farm and time of examination. It was found that more than one serotype of E. coli may exist in the pig body and contribute to the development of disease. The predominant serotypes, i.e. those comprising more than 10% of serologically determined strains, were found to exist in 6 of the investigated farms and not in the remaining ones. Among the predominant serotypes, particularly important seem to be strains with K88 antigen. For prophylaxis of piglet colibacteriosis in industrial farms in Poland two vaccines for sows are recommended: one containing the K88 antigen only and the other the following serotypes: 0149:K91,K88; 020:K57; 020:K83; 0157:K88; 01:K1; 0136:K78; 024:K?; 078:K80 and 0118:K? Strains belonging to these serotypes were the most prevalent in our strain collection.     

The effectiveness of inactivated vaccines applied parenterally to sows to control Escherichia coli diarrhea in piglets in an industrial fattening farm

Different vaccines against Escherichia coli diarrhea of piglets were applied parenterally in pregnant sows at an industrial fattening farm. The following vaccines were used: vaccine No. 1 with non-complete Freund's adjuvant. Tween 80 and Arlacel A, comprising O149:K91,K88; O139:K82; O8:K87,K88; O141:K85,K88; and O64:K? E. coli serotypes; vaccine No. 2 with paraffin oil instead of Freund's adjuvant, comprising the same E. coli serotypes as the vaccine No. 1; stable specific vaccine with 10% aluminium hydroxide, based on E. coli serotypes most frequently isolated from piglets which died at the farm (O149:K91,K88; O8:K87,K88; O20:K17; O64:K?); Gletvax K88 (Wellcome) and NOBI-VAC LT-K88 (Intervet International). The number of piglets which died up to the moment of weaning in comparison to the number of born ones was considered as an indicator of acquired protection. It was found that the most effective in conferring protection against E. coli diarrhea were: vaccine No. 1 and NOBI-VAC. The differences in the mortality rate between piglets originating from sows vaccinated with these vaccines and those from unvaccinated ones were statistically significant (P < 0.05). No significant differences were noted between controls and animals vaccinated with the remaining vaccines.     

The orbivirus genus. Diversity, structure, replication and phylogenetic relationships

The general properties of the orbiviruses have been examined at the physical, structural and molecular level. At the structural level, the orbiviruses (with the exception of the Kemerovo serogroup) appear similar. The replicative events are also similar, however differences in the ultrastructure of virus-specific structures and their association with components of the host cell have been observed. Further research in this area may be used to differentiate between the serogroups and even some serotypes, of orbiviruses. At the molecular level the properties of the genome can be used to determine relationships between members of the orbivirus genus. These relationships are revealed using a variety of techniques including serology and gene sequence analysis. Not only are the different serological responses to gene products present in the mature virus particle used for differential diagnosis, but the gene sequences themselves can also be utilized. Understanding of the relationships between these viruses is progressing to the point that insights into orbivirus molecular epidemiology is now possible.     

Affinity of microorganisms of the genus Ureaplasma to the reproductive organs of cattle

The purpose of this work was to define more precisely the role of Ureaplasma organisms in the aetiology of granular vulvovaginitis and balanoposthitis (GVVBP) of cattle. To contribute to this question the frequency and degree of infection with Ureaplasmas in two main groups of cattle was taken into account: (a) in cattle with symptoms of the mentioned disease, (b) in cattle without clinical symptoms. The samples of semen from 301 sires with symptoms of GVVBP and from 43 healthy sires as also vaginal mucus swabs from 96 cows with GVVBP and from 40 cows mated by the sire infected with Ureaplasma organisms and from 50 cows inseminated with semen which contained Ureaplasma organisms were taken for bacteriological examinations. The control group in relation to the above mentioned cows constituted of 22 heifers free from symptoms of GVVBP and neither inseminated nor mated naturally. It has been shown that on an average 78.1% of sires with pathological changes in the mucosa of the penis or prepuce and only 25.6% of healthy sires were infected with Ureaplasma organisms. The concentration of Ureaplasma organisms was also significantly higher in material obtained from sires with symptoms of the disease than in that from healthy animals. Ureaplasma organisms were demonstrated more frequently (72.7%) in cows with GVVBP than in cows without these symptoms (13.3%). Similarly, as in the material obtained from sires, in the material taken from cows with symptoms of the disease the concentration of Ureaplasma organisms was significantly higher than that in the material originating from the healthy cows. The obtained findings may indicate that Ureaplasma organisms play a role in the aetiology of GVVBP.     

Experimental infection and cross protection tests in calves with cytopathic strains of bovine rotavirus

Four cytopathic strains (81/32F, 81/36F, 81/40F, 82/80F) of bovine rotavirus were shown to be pathogenic for conventionally reared newborn calves. Calves were infected orally, using 3 calves for each isolate. All became febrile, were depressed and diarrhoeic. Two calves, one of which in the group of those infected with 81/36F isolate, and the other infected with strain 81/40F, were killed when moribund. A 3rd calf from the 81/36F infected group, died. At necropsy localized lesions of the small intestines, which are considered to be typical of rotavirus infection, were found. Virus was consistently isolated from the fecal samples of the inoculated calves up to 13 days post-inoculation. It was speculated that some differences existed in the virulence of the bovine rotaviruses tested. The cross protection tests revealed that 1 strain (81/36F) might be antigenically more complex than the others.     

猪轮状病毒腹泻病的诊断方法研究

猪轮状病毒性腹泻病主要引起猪的腹泻,对幼龄猪危害最大,以4周龄仔猪最易感。本文对猪轮状病毒腹泻病的临床诊断、电镜观察诊断、免疫学诊断以及基因分子诊断等方法的研究状况作了详细的论述。     

A serologic survey of bovine rotavirus infection in Italy

Serum neutralization tests conducted by microtiter procedure on 2970 serum samples from calves, heifers and adult cows from representative regions of Italy indicate that rotaviruses, and the infection which they cause, existed in Italy long before the virus was isolated. At the present time the infection is distributed fairly uniformly throughout the cattle population with both sexes and all age groups being equally susceptible.     

Prevalence of antibody to rotavirus in Moroccan cattle

A serological survey was carried out in order to determine the prevalence of antirotavirus antibodies in Moroccan cattle under different management conditions. From the 493 serum samples examined, 325 (65.9%) were found positive, using a counter-immunoelectroosmophoresis technique. Animals of indigenous breed coming from farms with rapid turnover or large number of animals, or having frequent contacts with imported cattle, had a higher rate of seropositivity; however, positive sera were also found in cattle from small farms in remote areas, showing that rotavirus infection is ubiquitous in that country. No relationship was found between the prevalence of anti-rotavirus antibodies and the frequence of calf diarrhoea. The percentage of seropositive animals in a herd has to be considered as an epidemiological indicator.     

Viral diarrhea of young animals: A review

A brief presentation is given of the enteric viral infections of young animals. The general characteristics of rotaviruses, coronaviruses and parvoviruses are reported, and the different aspects of the diseases associated with these viruses are discussed. Certain suggestions are made regarding the prevention of these diseases.     

Molecular characterization of bovine rotavirus strains circulating in northern Italy, 2003-2005

A total of 232 stools collected from calves with rotavirus infection in herds located in northern Italy from 2003 to 2005 was investigated. Determination of the rotavirus G and P types was carried out using nested RT-PCR. G6 was the most prevalent genotype, accounting for 78.5% of samples, G10 accounted for 9.9% of samples and viruses of G8 type were found in 4.7% of samples. In 3% of samples, viruses were not classified due to concomitant infection with more G type strains, whereas viruses in 3.9% of samples could not be characterized with any of the G-specific primers used in this study. Most common P types were P[11] and P[5], accounting for 65.1% and 25%, respectively. In 2.6% of cases, samples reacted with multiple P-specific primers; no P[1] serotype was identified. The G6P[11] combination was predominant throughout the study period, i.e. 52.5% in 2003, 50% in 2004 and 40% in 2005. The incidence of G6P[5] increased from 13.1% in 2003 to 27% in 2004 and 25.5% in 2005. The G10P[11] combination decreased markedly from 18% in 2003 to 2.6% in 2004, rising again to 7.3% in 2005. G8P[11] viruses were similarly present in 2003 (5%) and 2004 (4.3%), declining slightly in 2005 (1.8%).     

Comparative study of rotavirus strains of bovine and rabbit origin

Newborn calves were susceptible to infection with a rotavirus strain isolated from rabbits and, conversely, rabbits 4–5 weeks of age became ill and some died when inoculated with the rotavirus strain of bovine origin. However, the latter isolate appeared to be more virulent than the rabbit isolate in either calves or rabbits. Moreover, in reciprocal cross protection tests, carried out in calves and in rabbits, the rabbit rotavirus antiserum afforded only weak protection to challenge infection with either the homologous or the heterologous virus. By contrast, the protective level of the bovine rotavirus antiserum was relatively high.     

The duration of the foot-and-mouth disease virus carrier state in African buffalo (i) in the individual animal and (ii) in a free-living herd

The maintenance of a virus depends on a number of factors, including the duration of infectivity and the size of the available host population. In this work, foot-and-mouth disease virus was shown to persist in individual African buffalo (Syncerus caffer) for up to at least five years; thus, the duration of infectivity is more than adequate to cover the normal periods between calving peaks. In a small isolated free-living population which varied from 30 to 100 buffalo, two immunological types of foot-and-mouth disease virus were maintained for at least 24 years and through several generations.     

Effects in calves of mixed infections with bovine viral diarrhea virus and several other bovine viruses

The objective of this study was to verify whether a mixed infection in calves with bovine viral diarrhea virus (BVDV) and other bovine viruses, such as bovid herpesvirus-4 (BHV-4), parainfluenza-3 (PI-3) and infectious bovine rhinotracheitis (IBR) virus, would influence the pathogenesis of the BVDV infection sufficiently to result in the typical form of mucosal disease being produced.

Accordingly, two experiments were undertaken. In one experiment calves were first infected with BVDV and subsequently with BHV-4 and IBR virus, respectively. The second experiment consisted in a simultaneous infection of calves with BVDV and PI-3 virus or BVDV and IBR virus.

From the first experiment it seems that BVDV infection can be reactivated in calves by BHV-4 and IBR virus. Evidence of this is that BVDV, at least the cytopathic (CP) strain, was recovered from calves following superinfection. Moreover, following such superinfection the calves showed signs which could most likely be ascribed to the pathogenetic activity of BVDV. Superinfection, especially by IBR virus, created a more severe clinical response in calves that were initially infected with CP BVDV, than in those previously given the non-cytopathic (NCP) biotype of the virus. Simultaneous infection with PI-3 virus did not seem to modify to any significant extent the pathogenesis of the experimentally induced BVDV infection whereas a severe clinical response was observed in calves when simultaneous infection was made with BVDV and IBR virus.     

Identification of a G2-like porcine rotavirus bearing a novel VP4 type, P[32]

A porcine group A rotavirus (GARV) strain, 61/07/Ire, was isolated from a 4–5 week asymptomatic piglet, during an epidemiological survey of porcine herds in Southern Ireland, in 2007. The nucleotide (nt) and amino acid (aa) sequence of the full-length VP4 protein of the PoRV strain 61/07/Ire was determined. Based on the entire VP4 open reading frame (nt), strain 61/07/Ire displayed ≤ 76.5% identity to representatives of the established 31 P-types, a value far lower than the percentage identity cutoff value (80%) established by the Rotavirus Classification Working Group (RCWG) to define a novel P genotype. Strain 61/07/Ire revealed low aa identity, ranging from 57.1% to 83.6%, to the cognate sequences of representatives of the various P genotypes. The aa identity was lower in the VP8* trypsin-cleavage fragment of the VP4, which encompasses the VP4 hypervariable region, ranging from 36.9% to 75.3%. Sequence analyses of the VP7, VP6, and NSP4 genes revealed that the GARV strain 61/07/Ire possessed a G2-like VP7, an E9 NSP4 genotype and an I5 VP6 genotype. Altogether, these results indicate that the GARV strain 61/07/Ire should be considered as a prototype of a new VP4 genotype, P[32], and provide further evidence for the vast heterogeneity of group A rotaviruses.     

Effect of cyclosporin A on murine experimental Salmonellosis

Investigations were undertaken to evaluate the effect of cyclosporin A (CyA) on primary infection of mice with Salmonella typhimurium. Further, its effect on delayed-type hypersensitivity (DTH) and antibody response to porin, an outer membrane protein of S. typhimurium, has been characterized under different CyA regimen. When mice were infected i.p. with 5 × 10⁴ live medium virulent organisms, the bacterial growth increased by about 2 log₁₀ in CyA treated mice. CyA administered daily for 2 weeks following immunization with porin caused profound suppression of DTH and both IgM and IgG antibody responses. Given a single dose of CyA 24 h before DTH elicitation, the drug had a marked suppressive effect on DTH, but not on the antibody response to porin. Treatment on days 0–5 following immunization had no effect on the manifestation of the DTH response nor on the anti-porin IgM response whereas an enhanced level of IgG was observed in this group.     

The epizootology of caprine herpesvirus (BHV-6) infections in goat populations in Greece

Previous preliminary studies had shown that caprine herpesvirus (BHV-6) infections exist in many countries where goats play an economical role. The extensive serum survey made in Greece reveals that the virus must be widespread because more than 50% of the goats have antibodies. The bucks were found to have a higher evidence of infections than the female goats. The kids possessing maternal antibodies became seronegative at the age of 4 months and new antibodies appeared at the age of 7–8 months. Observations in 2 closed goat herds showed that the virus does not spread during the mating and lactating period. Neutralization titres increased or new infections in seronegative animals occurred after the summer when breeding took place. The virus is present in a latent state and recurrent infections are assumed to occur. In spite of that all our efforts to isolate the virus were unsuccessful, even after experimental immunosuppression.     

First report on Cryptosporidium parvum,Escherichia coli K99, rotavirus and coronavirus in neonatal lambs from north-center region,Algeria

The etiology of neonatal diarrhea is multifactorial and remains one of the greatest health problems in sheep livestock farming. Faecal samples from 559 neonatal lambs aged less than 30 days from 30 sheepfolds located in the north-center region of Algeria were screened with pathogen-specific antigen ELISA for Cryptosporidium parvum, Escherichia coli K99, rotavirus, and coronavirus. Of the 559 lambs, 312 (58.81 %), 155 (27.72 %), 72 (12.88 %) and 20 (3.57 %) were positives for C. parvum, E. coli K99, rotavirus and coronavirus antigens, respectively. The prevalence of C. parvum was the highest (p < 0.0001). C. parvum, E. coli K99, rotavirus and coronavirus were observed in 23 (76.66 %), 17 (56.66 %), 9 (30 %) and 3 (10 %) sheepfolds, respectively. Compared to age, the prevalence of C. parvum was highest during the second and third week of age (p < 0.001). In contrast, other pathogens were found to be more frequent in lambs aged ≤7 days (p < 0.001). The number of lambs with diarrhea was 280 (50.09 %) of which 280 (100 %), 127 (45.35 %), 52 (18.57 %) and 10 (3.57 %) were found to be infected with C. parvum, E. coli K99, rotavirus and coronavirus, respectively (p < 0.0001). In various combinations, mixed infections were detected only with C. parvum. This is the first report of C. parvum, E. coli K99, rotavirus, and coronavirus in ≤30-days old neonatal lambs in Algeria. Special attention should be given to the first colostrum feeding, hygiene of the farm, prevention and control measures for a better prevention of neonatal diarrhea in lambs.     

Description of electrophoretic loci and tissue specific gene expression in the horseshoe bat genus Rhinolophus (Rhinolophidae)

The number of loci encoding an enzyme system, tissue specificity of gene expression and the degree of gene expression in various tissues are often not mentioned in evolutionary studies, but could indirectly provide evidence of evolutionary relationships. Protein electrophoresis was used to study the distributions and tissue specificity of gene expression of enzymes encoded by 42 loci in Rhinolophus clivosus and R. landeri, the genetically most divergent of the ten species of southern African horseshoe bats. No differences in gene expression were found between R. clivosus and R. landeri and isozyme patterns may be compared with other bat species to derive possible phylogenetic relationships.