Rotaviral and coronaviral diarrhea

A number of different viruses can be primary pathogens in the neonatal calf diarrhea complex. By far the most common viruses causing calfhood diarrhea found throughout the world are rotaviruses and coronaviruses. Primary infection of newborn calves with either one of these viruses can cause severe intestinal alterations and diarrhea. Rotaviruses can produce high-morbidity outbreaks of diarrhea in calves under 10 days of age. Morality is variable mainly owing to secondary bacterial infections and electrolyte imbalances. Rotavirus infection of the small intestinal mucosa leads to loss of enterocytes of the upper third of the intestinal villi with subsequent villous atrophy and malabsorption. There is growing evidence that different rotavirus serotypes of different pathogenicity exist. Coronavirus infections can produce high-morbidity outbreaks of diarrhea in calves under 20 days of age, with variable mortality due to secondary complications. Coronaviruses affect not only the small intestinal mucosa, producing significant villous atrophy, but also the colon, causing a very severe intestinal damage that can lead to death due to subsequent electrolyte disturbances. All coronaviruses associated with neonatal calf diarrhea appear to be of the same serotype. The etiologic diagnosis of viral diarrheas of calves requires the support of the laboratory. One of the most useful diagnostic methods is the examination of fecal extracts for the presence of virus particles by electron microscopy. Other antigen-detection procedures like enzyme immunoassays have been found to be useful in the diagnosis of rotaviral diarrheas. The sample of choice for these diagnostic tests is a fresh fecal sample collected directly from the calf as close as possible to the onset of diarrhea. Samples from more than one calf during the outbreak enhance the laboratory ability to establish a proper viral diagnosis.     

Rotaviral antibodies in cow's milk.

In the past, it has been reported that neonatal diets made from unheated cow's milk were superior to those made from heated cow's milk. It was observed that piglets were equally protected from rotaviral diarrhea when they were fed diets made from either unheated milk that came from a cow immunized against porcine rotavirus or from a cow that was not immunized. Because of this observation, we examined four pools of "normal" cows' colostrum and 58 samples of "normal" cow's milk for the presence of antibody to rotavirus. All pools of colostrum, collected in four different years, had immunofluorescent antibody titers of 1:100 to rotavirus. Seventy-two percent of the samples of milk were also positive--titer no higher than 1:10. Antibodies to rotavirus were found in cow's milk at a creamery prior to but not after pasteurization. Rotaviral antibodies were detected in one out of eight brands of milk bought at the market--perhaps indicating inadequate pasteurization for this brand. These results support the proposition that, at least in part, unheated milk is superior to heated milk because unheated milk contains antibody to an ubiquitous enteropathogen like rotavirus.     

Feline immunodeficiency virus: a brief review.

Feline immunodeficiency virus (FIV), previously known as feline T-lymphotropic lentivirus (FTLV), was first described by Pedersen et al. (1987) who isolated the virus from cats with a variety of clinical signs suggestive of immunodeficiency. Since then FIV has become one of the most studied feline viruses, not least because of its similarity to human immunodeficiency viruses (HIV) which cause acquired immunodeficiency syndrome (AIDS) in man.     

Feline retroviruses: a brief review

Representatives of all three retrovirus subfamilies are recognized in the cat: feline leukaemia virus (an Oncovirus), feline syncytium-forming virus (a Spumavirus) and feline immunodeficiency virus (a Lentivirus). Each of these is briefly reviewed.     

Dietary clays alleviate diarrhea of weaned pigs

Two experiments were conducted to determine whether 3 different clays in the nursery diet reduce diarrhea of weaned pigs experimentally infected with a pathogenic Escherichia coli. Weaned pigs (21 d old) were housed in individual pens of disease containment chambers for 16 d [4 d before and 12 d after the first challenge (d 0)]. The treatments were in a factorial arrangement: 1) with or without an E. coli challenge (F-18 E. coli strain; heat-labile, heat-stable, and Shiga-like toxins; 10(10) cfu/3 mL oral dose daily for 3 d from d 0) and 2) dietary treatments. The ADG, ADFI, and G:F were measured for each interval (d 0 to 6, 6 to 12, and 0 to 12). Diarrhea score (DS; 1 = normal; 5 = watery diarrhea) was recorded for each pig daily. Feces were collected on d 0, 3, 6, 9, and 12 and plated on blood agar to differentiate β-hemolytic coliforms (HC) from total coliforms (TC) and on MacConkey agar to verify E. coli. Their populations on blood agar were assessed visually using a score (0 = no growth; 8 = very heavy bacterial growth) and expressed as a ratio of HC to TC scores (RHT). Blood was collected on d 0, 6, and 12 to measure total and differential white blood cell (WBC) counts, packed cell volume (PCV), and total protein (TP). In Exp. 1 (8 treatments; 6 replicates), 48 pigs (6.9 ± 1.0 kg of BW) and 4 diets [a nursery control diet (CON), CON + 0.3% smectite (SM), CON + 0.6% SM, and CON until d 0 and then CON + 0.3% SM] were used. The SM treatments did not affect growth rate of the pigs for the overall period. In the E. coli challenged group, the SM treatments reduced DS for the overall period (1.77 vs. 2.01; P < 0.05) and RHT on d 6 (0.60 vs. 0.87; P < 0.05) and d 9 (0.14 vs. 0.28; P = 0.083), and altered differential WBC on d 6 (neutrophils, 48 vs. 39%, P = 0.092; lymphocytes, 49 vs. 58%, P = 0.082) compared with the CON treatment. In Exp. 2 (16 treatments; 8 replicates), 128 pigs (6.7 ± 0.8 kg of BW) and 8 diets [CON and 7 clay treatments (CON + 0.3% SM, kaolinite, and zeolite individually and all possible combinations to total 0.3% of the diet)] were used. The clay treatments did not affect growth rate of the pigs. In the E. coli challenged group, the clay treatments reduced DS for the overall period (1.63 vs. 3.00; P < 0.05), RHT on d 9 (0.32 vs. 0.76; P < 0.05) and d 12 (0.13 vs. 0.39; P = 0.094), and total WBC on d 6 (15.2 vs. 17.7 × 10(3)/μL; P = 0.069) compared with the control treatment. In conclusion, dietary clays alleviated diarrhea of weaned pigs.     

猪增生性肠炎与育肥猪的腹泻问题

消化道疾病往往导致养猪生产中相当大的经济损失,尽管最初的症状只是粪便黏稠不成形.一方面可能是致病性因素改变了猪消化道环境,使机体变得虚弱;另一方面,当育成猪受到腹泻影响时,应该考虑到还有很多可能的原因.     

断奶仔猪营养性腹泻及其防治措施

1　断奶仔猪的营养生理特点1.1　代谢机能旺盛,相对生长迅速仔猪物质代谢旺盛,生长快,2 0日龄仔猪体重为初生时的4 .5倍,每千克体增重的蛋白质沉积量为9～14 g ,而成年猪每千克体增重沉积的蛋白质仅为0 .3～0 .4 g ,前者是后者的30～35倍。仔猪6 0日龄体重为初生重的15 .7倍,钙     

Organic acid profiles in feces of pigs with pathogenic or non-pathogenic diarrhea.

A chemical characteristic of the feces of diarrheal piglets permits differentiation among piglets receiving antibiotic treatment and those with colibacillosis or dyspepsia. A high concentration of lactic or succinic acid was observed in the diarrheic feces of piglets receiving antibiotic treatments and those with dyspepsia; however, no lactic or succinic acids were detected in piglets with colibacillosis. There was, however, little difference in the total concentration of organic acids among the three types of diarrheal illnesses. A quantitative analysis of lactic and succinic acids in diarrheic feces might provide a means for rapidly differentiating between colibacillosis and non-pathogenic diarrheas in piglets.     

Pneumonia of pigs: a review

Pneumonia of pigs is one of the more important disease factors limiting pig production. Of the varieties of pneumonia affecting this species enzootic pneumonia caused by Mycoplasma spp. is the most common and most important. The major effects of this disease are lowered food conversion ratio and poor weight gain. Deaths are usually the result of secondary infection by necrotising, pus-forming bacteria. Eradication of the disease is expensive and requires depopulation and restocking. Control and treatment by antimicrobial agents is most effective if the drug combination used takes regard of the bacteria complicating the disease on any particular property. Other forms of pneumonia such as those caused by Haemophilus pleuropneumoniae, Salmonella cholerae-suis and Aujeszky’s disease virus can be important on individual farms. The role of other agents such as Bordetella bronchiseptica and adenoviruses in respiratory disease of pigs remain to be clarified.     

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.     

Porcine epidemic diarrhea: an emerging disease in Tibetan pigs in Tibet,China

Tropical Animal Health and Production - Porcine epidemic diarrhea virus (PEDV) is a devastating cause of diarrhea in pigs worldwide, and has caused enormous economic losses in the pork industry. To...     

Humoral immune response to human cytomegalovirus proteins: a brief review.

Although human cytomegalovirus (HCMV) has a genome of 150 x 10(6) Da, and a protein-coding content of over 200 open reading frames, few viral proteins seem able to elicit a strong antibody response in the natural host during viral infection. The immunodominant polypeptides include a component of 72 kDa among immediate early proteins, a polypeptide of 52 kDa among delayed early proteins and a glycoprotein complex of 58 and 93-130 kDa and two phosphoproteins of mol. wt 150 and 65 kDa among the structural proteins. Following a general overview of the humoral immune response, this brief survey mainly deals with the antibody response to these proteins. As significant epitopes of the major HCMV immunogenic polypeptides have been expressed in procaryotic cells over the last few years, an overview of the state of the art in this particular field will also be given.     

Rotaviruses: diversity and zoonotic potential--a brief review

Rotaviruses, a genus within the family Reoviridae, are among the most important etiological agents of severe diarrhoeal illness in humans and animals worldwide. Their genome, consisting of 11 segments of double-stranded RNA, is characterized by genetic variability including (i) point mutations, (ii) genomic reassortment, and (iii) genome rearrangements, thus leading to the considerable diversity of rotaviruses. Animal rotaviruses are regarded as a potential reservoir for genetic exchange with human rotaviruses.There is now increasing evidence that animal rotaviruses can infect humans, either by direct transmission of the virus or by contributing one or several genes to reassortants with essentially a human strain genetic background. As mixed infections are a prerequisite for reassortment events, cosurveillance of animal and human rotavirus strains will be vital to gain a better understanding of the relationships between cocirculating viruses, as well as assessing any relevant vaccination programs.     

The pathogenesis of edema disease in pigs. A review.

Edema disease is known to cause important losses in the period shortly after weaning. Although the disease is known for many decades, intensive studies with bacterial lysates of pathogenic E. coli, followed by biotechnological research the last ten years, has led to a better understanding of its pathogenesis. Especially the impact of the toxin is clearly established. Evidence also exists that adhesion factors play a crucial role in the pathogenesis of edema disease.