Peracute Death Research Articles

Silent Infection of Highly Pathogenic Avian Influenza Virus (H5N1) Clade 2.3.4.4b in a Commercial Chicken Broiler Flock in Italy.

From October 2021 to January 2022, different incursions of clade 2.3.4.4b H5N1 HPAIV (Highly Pathogenic Avian Influenza Virus) occurred in several Italian regions with its main diffusion in Densely Poultry Populated Areas (DPPAs) of north-eastern Italy. Monitoring and control activities applied in the affected area clearly evidenced that turkeys and broilers were the most affected species, although several flocks of broilers at times resulted HPAIV H5N1 infected in absence of increased mortality and/or clinical signs. Thus, an approach based on sampling dead birds was adopted in the broiler sector to improve the early detection of infection; this protocol allowed us to confirm that 15 farms were HPAIV-infected with birds ready to be delivered to the slaughterhouse. The aim of this report is to describe the results of the diagnostic activities carried out in one HPAIV H5N1-infected broiler farm, three days after laboratory confirmation during the pre-movement testing without showing increased mortality or clinical signs. Thus, clinical signs, daily cumulative mortality rate (CMR), virus shedding, seroconversion, pathobiology of clade 2.3.4.4b H5N1 HPAIV as well as Avian Influenza Viruses (AIVs) environmental contamination were thoroughly examined in the infected holding. Such in-depth investigation demonstrated low infection prevalence in live birds, low environmental contamination, no seroconversion for AIVs, gross and microscopic findings compatible with systemic infection with peracute death in H5N1 HPAIV-infected birds.

Clostridium perfringens Types A and D Involved in Peracute Deaths in Goats Kept in Cholistan Ecosystem During Winter Season

Enterotoxemia is a severe and peracute disease caused by Clostridium perfringens (C. perfringens) rendering high mortality leading to huge economic losses, especially in small ruminants. The bacterium induces peracute death in animals based on the rapid production of different lethal toxins. Mortality occurred three private herds of two breeds, i.e., Makhi Cheeni and Beetal, and one non-descriptive (Teddy) herds reared in the desert area of Bahawalpur, Pakistan. At necropsy, tissue samples for histopathology and intestinal contents for bacterial isolation and culture were collected. Following the standard procedure, tissue slides were prepared. Multiplex PCR was used to identify toxinotypes using specific primers. Morbidity, mortality, and case fatality in Makhi Cheeni, Beetal, and Teddy goats caused by enterotoxemia were 87.58, 75.81, and 76.11%, respectively. Based on toxinotypes in the present outbreaks, C. perfringens type A (cpα = 20.7%; cpα + cpβ2 = 11.2%) and C. perfringens type D (cpα + cpβ2 + etx = 47.7%; cpα + etx = 20.7%) were detected. Deaths due to C. perfringens type D (68.10%) were significantly higher (p < 0.001) compared with deaths by C. perfringens type A (34.90%). Petechiation of serosal surfaces, hemorrhage of intestines, lungs, and liver were seen. Kidneys were soft, and under the microscope, tubules were studded with erythrocytes. There was stunting and fusion in the intestinal villi. From this study, we concluded that endotoxemia can occur in any season; thus, a proper vaccination schedule must be followed for the protection of small ruminants' health.

Outbreaks of Typhlocolitis Caused by Hypervirulent Group ST1 Clostridioides difficile in Highly Immunocompromised Strains of Mice.

Clostridioides difficile is an enteric pathogen that can cause significant clinical disease in both humans and animals. However, clinical disease arises most commonly after treatment with broad-spectrum antibiotics. The organism's ability to cause naturally occurring disease in mice is rare, and little is known about its clinical significance in highly immunocompromised mice. We report on 2 outbreaks of diarrhea associated with C. difficile in mice. In outbreak 1, 182 of approximately 2, 400 NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) and related strains of mice became clinically ill after cessation of a 14-d course of 0.12% amoxicillin feed to control an increase in clinical signs associated with Corynebacterium bovis infection. Most mice had been engrafted with human tumors; the remainder were experimentally naïve. Affected animals exhibited 1 of 3 clinical syndromes: 1) peracute death; 2) severe diarrhea leading to euthanasia or death; or 3) mild to moderate diarrhea followed by recovery. A given cage could contain both affected and unaffected mice. Outbreak 2 involved a small breeding colony (approximately 50 mice) of NOD. CB17-Prkdcscid/NCrCrl (NOD-scid) mice that had not received antibiotics or experimental manipulations. In both outbreaks, C. difficile was isolated, and toxins A and B were detected in intestinal content or feces. Histopathologic lesions highly suggestive of C. difficile enterotoxemia included fibrinonecrotizing and neutrophilic typhlocolitis with characteristic 'volcano' erosions or pseudomembrane formation. Genomic analysis of 4 isolates (3 from outbreak 1 and 1 from outbreak 2) revealed that these isolates were closely related to a pathogenic human isolate, CD 196. To our knowledge, this report is the first to describe naturally occurring outbreaks of C. difficile-associated typhlocolitis with significant morbidity and mortality in highly immunocompromised strains of mice.

Borna disease outbreak with high mortality in an alpaca herd in a previously unreported endemic area in Germany.

Borna disease virus 1 (BoDV-1) is the causative agent of Borna disease, an often fatal neurologic condition of domestic mammals, including New World camelids, in endemic areas in Central Europe. Recently, BoDV-1 gained further attention by the confirmation of fatal zoonotic infections in humans. Although Borna disease and BoDV-1 have been described already over the past decades, comprehensive reports of Borna disease outbreaks in domestic animals employing state-of-the-art diagnostic methods are missing. Here, we report a series of BoDV-1 infections in a herd of 27 alpacas (Vicugna pacos) in the federal state of Brandenburg, Germany, which resulted in eleven fatalities (41%) within ten months. Clinical courses ranged from sudden death without previous clinical signs to acute or chronic neurologic disease with death occurring after up to six months. All animals that underwent necropsy exhibited a non-suppurative encephalitis. In addition, six apparently healthy seropositive individuals were identified within the herd, suggesting subclinical BoDV-1 infections. In infected animals, BoDV-1 RNA and antigen were mainly restricted to the central nervous system and the eye, and sporadically detectable in large peripheral nerves and neuronal structures in other tissues. Pest control measures on the farm resulted in the collection of a BoDV-1-positive bicoloured white-toothed shrew (Crocidura leucodon), while all other trapped small mammals were negative. A phylogeographic analysis of BoDV-1 sequences from the alpacas, the shrew and BoDV-1-positive equine cases from the same region in Brandenburg revealed a previously unreported endemic area of BoDV-1 cluster 4 in North-Western Brandenburg. In conclusion, alpacas appear to be highly susceptible to BoDV-1 infection and display a highly variable clinical picture ranging from peracute death to subclinical forms. In addition to horses and sheep, they can serve as sensitive sentinels used for the identification of endemic areas.

One Decade of Experience with Endoscopic Stenting for Intrathoracic Anastomotic Leakage after Esophagectomy: Brilliant Breakthrough or Flash in the Pan?

Management of intrathoracic anastomotic leakage after esophagectomy by means of endoscopic stent insertion has gained wide acceptance as an alternative to surgical reintervention. Between January 2004 and March 2013 all patients who underwent esophagectomy at a German high-volume center for esophageal surgery were included in this retrospective study. The study comprises 356 patients. Anastomotic leakage occurred in 49 cases. There were no significant differences in age, American Society of Anesthesiologists (ASA) score, or frequency of neoadjuvant therapy between cases with and without leak. However, leak patients sustained significantly more often postoperative pneumonia, pleural empyema, sepsis, and acute renal failure. Moreover, leak victims had higher odds for fatal outcome (16 of 49 vs 33 of 307; odds ratio, 5.94; 95% confidence interval, 2.65 to 13.15; P < 0.0001). The leakage was amendable by endoscopic stenting in 29 cases, whereas rethoracotomy was mandatory in 20 patients. Between stent and rethoracotomy cases, we observed no significant differences in age, ASA score, neoadjuvant therapy, occurrence of pneumonia, pleural empyema, or tracheostomy rate. Rethoracotomy patients sustained more often sepsis (16 of 20 vs 14 of 29; P = 0.04) and acute renal failure (nine of 20 vs four of 29; P = 0.02) as expression of more severe septic disease. Nevertheless, there was no significant difference in mortality (seven of 29 vs nine of 20; P = 0.21). Furthermore, we observed three cases of stent-related aortic erosion with peracute death from exsanguination. Despite being the preferred treatment option, endoscopic stenting was only feasible in approximately 60 per cent of all intrathoracic leaks. The results are marred by the occurrence of deadly vascular erosion. Therefore, individualized strategies should be preferred to a general recommendation for endoscopic stenting.

Clinical Features, Intestinal Histopathology, and Outcome in Protein‐Losing Enteropathy in Yorkshire Terrier Dogs

BackgroundA poorly understood protein‐losing enteropathy (PLE) disorder has been reported in Yorkshire Terrier dogs.ObjectivesTo describe clinical features, intestinal histopathology, and outcome in Yorkshire Terrier dogs with PLE, and to identify variables predictive of outcome.AnimalsThirty client‐owned Yorkshire Terrier dogs with PLE.MethodsRetrospective study. Records of dogs with a diagnosis of PLE were reviewed. Intestinal histopathology was interpreted using the World Small Animal Veterinary Association gastrointestinal histopathology classification system. Discriminate analysis techniques were used to identify variables predictive of outcome.ResultsFemales outnumbered males (20/30). Median age was 7 years (range 1–12). Common clinical signs were diarrhea (20/30), vomiting (11), ascites and abdominal distension (11), and respiratory difficulty (8). Histopathologic abnormalities included villous lymphatic dilatation, crypt lesions, villous stunting, and variable increases in cellularity of the lamina propria. All dogs were treated with glucocorticoids. Of 23 dogs with long‐term follow‐up, 9 had complete, and 3 had partial, resolution of signs, and 11 failed to respond to treatment. Median survival of responders was 44 months and of nonresponders was 12 months, with 4 dogs experiencing peracute death. Vomiting, monocytosis, severity of hypoalbuminemia, low blood urea nitrogen concentration, and villous blunting were predictive of survival <4 months.ConclusionsIn addition to classic GI signs, Yorkshire Terriers with PLE often show clinical signs associated with hypoalbuminemia and low oncotic pressure. Lymphatic dilatation, crypt lesions, and villous stunting are consistent histopathologic findings. Clinical outcomes are variable, but many dogs experience remission of clinical signs and prolonged survival.

Quantitative immunohistochemical analysis of human brain basic fibroblast growth factor, glial fibrillary acidic protein and single-stranded DNA expressions following traumatic brain injury

Previous studies demonstrated the healing process after traumatic brain injury (TBI), usually at the site or in the area adjacent to the injury, in connection with wound timing. However, the whole brain condition after TBI has not been elucidated clearly. In the present study, we investigated immunohistochemistry of the basic fibroblast growth factor (bFGF), glial fibrillary acidic protein (GFAP) and single-stranded DNA (ssDNA) in the parietal lobe and hippocampus distant from the primary injury site in forensic autopsy cases of TBI (n=174). Characteristic findings were detected with regard to brain compression signs and survival time (ST). Peracute deaths (n=22) had a lower GFAP positivity in the parietal white matter. Fatalities without a brain compression sign (parahippocampal herniation/Duret hemorrhage; n=53) had a lower brain weight without glial loss; however, GFAP positivity in the parietal white matter was decreased during ST of <12h, and glial bFGF positivity was increased at each site in deaths after 12h to 3 days, followed by a delayed neuronal loss after 3 days. Fatalities with a brain compression sign (n=78) showed a higher brain weight, and gradual glial and neuronal losses with an early increase of glial bFGF positivity in the parietal cerebral cortex (ST <0.5h). This was followed by an increase of glial bFGF positivity in other sites (ST, 6–24h), and final decreases of glial bFGF and GFAP positivities with increased neuronal ssDNA positivity in the parietal lobe and hippocampus (ST >3 days), which were detected in earlier deaths despite decompressive craniectomy (ST, 12–60h; n=21). These observations suggest that the combined use of bFGF, GFAP and ssDNA immunohistochemistry can be used to evaluate the severity of damage and response of brain after TBI.

Emergence and establishment of Usutu virus infection in wild and captive avian species in and around Zurich, Switzerland—Genomic and pathologic comparison to other central European outbreaks

In late summer 2006 considerable mortality in wild and captive Passeriformes and Strigiformes was observed in Zurich, Switzerland. All animals were found in a range of 2 km 2. Observed clinical signs involved depression, ruffled plumage, incoordination, seizures and peracute death. Nutritional status was generally moderate to poor in wild birds, and variable in captive animals. Necropsy showed marked splenomegaly, a mild hepatomegaly, and pulmonary hyperemia in most animals. Histopathologic lesions were very discrete and consisted mainly of neuronal necrosis, leucocytolysis in and around the brain blood vessels, and miliary liver necrosis. The diagnosis Usutu virus (USUV) infection was established by USUV-specific immunohistochemistry and reverse transcription-polymerase chain reaction. Partial nucleotide sequence comparisons revealed > 99% identity between the viruses that emerged in Zurich in 2006, in Vienna in 2001, and in Budapest in 2005. Since 2008 a significantly lower mortality was observed in wild Passeriformes, but USUV infection was confirmed for the first time beyond Zurich city limits. Indoor housing and regular treatment against ectoparasites are likely to have prevented acute USUV disease in captive Strigiformes. USUV is a mosquito-borne flavivirus causing fatalities in various avian species. After the initial European outbreaks in Austria in 2001 it appears that the virus has extended its range in Central Europe and has established a transmission cycle between local bird and mosquito species. Further episodes of increased avian mortality in the forthcoming years, with impact on wild and captive bird populations, predominantly Passeriformes and Strigiformes, can be anticipated. Furthermore, the possibility of broader dispersal of USUV in Europe during the next mosquito seasons must be considered and an increased mortality in Passeriformes and Strigiformes must be expected until protective “flock immunity” is established. Collections of valuable and endangered Passeriformes and Strigiformes, especially young of the year, should therefore be housed indoors or treated against ectoparasites at acceptable intervals between July and September each year.

Multiple peracute deaths in a colony of Syrian hamsters (Mesocricetus auratus)

Multiple peracute deaths in a colony of Syrian hamsters (Mesocricetus auratus)

Plantas tóxicas para ruminantes e eqüídeos no Norte Piauiense

Este trabalho teve por objetivo realizar um levantamento sobre as plantas tóxicas para ruminantes e equídeos na Mesorregião Norte do Piauí. Foram feitas 71 entrevistas a médicos veterinários, engenheiros agrônomos, técnicos agrícolas e produtores de 16 municípios, entrevistando pelo menos quatro pessoas por município. As plantas comprovadamente tóxicas que foram apontadas com maior frequência na região estudada foram Ipomoea asarifolia, que causa intoxicações em pequenos ruminantes em todas as áreas visitadas. Stryphnodendron coriaceum pelas mortes que ocasiona é, aparentemente, a planta que causa maiores perdas econômicas na mesorregião estudada. Enterolobium contortisiliquum também foi citada como causa importante de sinais digestivos, abortamentos e fotossensibilização em bovinos da região. Os entrevistados confirmaram a ocorrência de surtos de intoxicação em bovinos por Thiloa glaucocarpa no inicio do período chuvoso. Manihot spp. e Piptadenia macrocarpa são plantas cianogênicas apontadas como causa de mortes superagudas em bovinos. Outras plantas relatadas como tóxicas pelos entrevistados, mas sem que haja comprovação de sua toxicidade, foram Buchenavia tomentosa, Caesalpinia sp., Brunfelsia sp., Luetzelburgia sp., Hybantus ipecaconha, Phisalys angulata e Spondias luta. De acordo com os entrevistados os frutos de Buchenavia tomentosa causam sinais digestivos e abortos em caprinos, ovinos e bovinos. Produtores relatam surtos de intoxicação em caprinos que apresentam sinais digestivos e morte após a ingestão de favas de Luetzelburgia sp. Brunfelsia sp. é relatada como causa de alterações nervosas, no começo das chuvas, quando os animais ingerem as folhas e flores e os asininos são aparentemente mais afetados. Os frutos de Spondias luta foram mencionados como causa de diarréia em caprinos. Experimentos não publicados demonstraram a toxicidade de Brunfelsia sp. em ovinos e de Luetzelburgia sp. como causa de sinais digestivos e mortes em caprinos. Novos experimentos devem ser feitos para comprovar a toxicidade de outras plantas mencionadas nas entrevistas.

Association of Increased Pathogenicity of Asian H5N1 Highly Pathogenic Avian Influenza Viruses in Chickens with Highly Efficient Viral Replication Accompanied by Early Destruction of Innate Immune Responses

The Asian H5N1 highly pathogenic avian influenza (HPAI) viruses have been increasing in pathogenicity in diverse avian species since 1996 and are now widespread in Asian, European, and African countries. To better understand the basis of the increased pathogenicity of recent Asian H5N1 HPAI viruses in chickens, we compared the fevers and mean death times (MDTs) of chickens infected with the Asian H5N1 A/chicken/Yamaguchi/7/04 (CkYM7) strain with those infected with the H5N1 Duck/Yokohama/aq10/03 (DkYK10) strain, using a wireless thermosensor. Asian H5N1 CkYM7 caused peracute death in chickens before fever could be induced, whereas DkYK10 virus induced high fevers and had a long MDT. Real-time PCR analyses of cytokine mRNA expressions showed that CkYM7 quickly induced antiviral and proinflammatory cytokine mRNA expressions at 24 h postinfection (hpi) that suddenly decreased at 32 hpi. In contrast, these cytokine mRNA expressions increased at 24 hpi in the DkYK10 group, but decreased from 48 hpi onward to levels similar to those resulting from infection with the low-pathogenicity H5N2 A/chicken/Ibaraki/1/2004 strain. Sequential titrations of viruses in lungs, spleens, and kidneys demonstrated that CkYM7 replicated rapidly and efficiently in infected chickens and that the viral titers were more than twofold higher than those of DkYK10. CkYM7 preferentially and efficiently replicated in macrophages and vascular endothelial cells, while DkYK10 grew moderately in macrophages. These results indicate that the increased pathogenicity in chickens of the recent Asian H5N1 HPAI viruses may be associated with extremely rapid and high replication of the virus in macrophages and vascular endothelial cells, which resulted in disruption of the thermoregulation system and innate immune responses.

A Review of Highly Pathogenic Avian Influenza in Birds, With an Emphasis on Asian H5N1 and Recommendations for Prevention and Control

Avian influenza is a disease of both veterinary and public health importance. Influenza A viruses infect a range of hosts, including humans, and can cause significant morbidity and mortality. These viruses have high genetic variability, and new strains develop through both mutation and reassortment. Modes of transmission as well as the location of viral shedding may differ both by host species and by viral strain. Clinical signs of influenza A virus infection in birds vary considerably depending on the viral subtype, environmental factors, and age, health status, and species of the bird and range from decreased egg production and gastrointestinal manifestations to nervous system disorders and respiratory signs. Most commonly, peracute death with minimal clinical disease is observed in poultry infected with a highly pathogenic avian influenza virus. There are various prevention and control strategies for avian influenza, including education, biosecurity, surveillance, culling of infected animals, and vaccination. These strategies will differ by institution and current federal regulations. Each institution should have an established biosecurity protocol that can be properly instituted. Lastly, human health precautions, such as proper hand hygiene, personal protective equipment, and employee health monitoring, are imperative for at-risk individuals.

Pharmacokinetics and Safety of Acyclovir in Tragopans (Tragopan species)

In response to multiple peracute deaths caused by herpesvirus in several pheasant species, a study was designed to determine the absorption, distribution, and linearity of acyclovir in hybrid tragopans (Tragopan caboti × Tragopan temminckii). Acyclovir was administered to 5 healthy adult tragopans, 3 males and 2 females, in a single dose of 40, 80, or 120 mg/kg PO. Blood samples were collected at 1, 2, 6, 12, and 24 hours after administration, and concentrations of acyclovir were measured by reverse phase high-performance liquid chromatography (HPLC) with a C-8 column and ultraviolet (UV) detection. Although plasma concentrations were not linear, results from this study suggest that a dosage of 120 mg/kg PO q12h in tragopans may achieve effective plasma concentrations (1.0 μg/ml) for potential treatment and prevention of herpesviral infections. However, further studies are needed to determine if this dosage is safe for repeated administration.

New Paradigms for Bovine Viral Diarrhea Virus

Bovine viral diarrhea virus (BVDV) continues to be the bane of the US beef and dairy industry. BVDV infections cause clinical signs that vary from peracute death to inapparent infection. Even these inapparent BVDV infections can result in persistent infection (PI) of susceptible fetuses. The macrophage expresses cell surface markers that are important for phagocytosis and bacteria killing, and also for stimulation of T helper cells and for immune surveillance and killing by cytotoxic T cells (CTL). In this study, our objective was to measure the effect of BVDV on the macrophage function (phagocytosis and pathogen killing) and surface marker expression (CD14, MHCI and MHCII).

Problems associated with the diagnosis of vitality in burned bodies

The most important signs of vitality in burned bodies are soot deposits in the respiratory tract, the esophagus and the stomach as well as elevated CO–Hb values in the blood. But these findings show only that a person was exposed to fire fumes while alive; they are no indicator for vital heat exposure. As the external findings in burned bodies are often not very conclusive due to postmortem consumption by the fire, the internal findings are all the more important. Macroscopic signs that hot fumes were inhaled may be edematous swelling and vesicular detachment of the mucosa in the pharynx, the larynx and/or the upper section of the esophagus. As histological changes in the respiratory tract soot deposits, vesicular detachment of the epithelium, hyperemia and edema of the tracheal and bronchial mucosa as well as increased secretion of mucus have been described. These findings may partly be absent although the victim was alive during the fire, which can make diagnosis more difficult. Especially in peracute deaths vitality findings are usually sparse. The significance of the macroscopic and histological parameters of vitality was systematically investigated on the basis of our own autopsy material from the years 1996–2002 (88 cases) and compared with the statements found in the literature. In our study material, the vitality parameters were incomplete in 23% of the burned corpses. In 3% of the cases the question whether there was an antemortem heat exposure could not be answered.

A quantitative RT-PCR assay of surfactant-associated protein A1 and A2 mRNA transcripts as a diagnostic tool for acute asphyxial death

Although an immunohistochemical investigation of pulmonary surfactant-associated protein A (SP-A) suggested a characteristic increase in fatal asphyxiation, no particular change was observed in the total amount of SP-A mRNA. SP-A is encoded by two highly similar genes, SP-A1 and SP-A2, which are differentially regulated in the expression. In the present study, to investigate the molecular pathology of SP-A, we established a method for quantitative RT-PCR assay of SP-A1 and SP-A2 mRNA transcripts. Using this method, fatalities from acute mechanical asphyxia ( n=12) and drowning ( n=9) were examined in comparison with control groups ( n=17) of acute myocardial infarction ( n=11) and peracute death due to brain lacerations ( n=6). The SP-A1/A2 ratio (mean value) was markedly elevated in mechanical asphyxia (6.72) and drowning (5.64), whereas it was low in controls (acute myocardial infarction, 2.80; brain lacerations, 2.56). The analysis of the SP-A1/A2 ratio may assist interpretation of the molecular alterations of SP-A related to acute asphyxial death.

Case report

In the last three years, veterinary practitioners from Iowa, Minnesota and Wisconsin, USA, have reported, with increased frequency, a peracute, segmental haemorrhagic enteritis in mature dairy cattle. Based on these reports, clinicians at Iowa State University have begun to suspect Jejunal Haemorrhage Syndrome (JHS) as a new emerging disease syndrome. The morbidity rate for this disease has been sporadic, and mortality approaches 85-100% due to the peracute nature and severity of this disease. There are frequently no prodromal signs and the mature cow is found dead, or an individual cow is found down and in systemic collapse. Clinical signs include sternal recumbency, diaphoresis, enophthalmia and signs of shock due to occlusion of the small intestine. Ballotment of the standing cow in the lower right abdominal area can elicit a pronounced fluid slosh, due to backup of ingesta and fluid behind the occlusive lesion. Signs of abdominal pain include bruxism, vocalization, treading and kicking at the abdomen. At necropsy, segmental lesions localized to the jejunum are observed. These areas consist of frank haemorrhage and immediate clotting, forming a functional occlusion of the small intestinal lumen. Necrosis of the lumen may or may not be apparent. In April 1999, the Veterinary Diagnostic and Production Animal Medicine Department at the Iowa State University College of Veterinary Medicine was asked by a northeastern Iowa veterinarian to investigate recurring sporadic peracute death losses. Examination of affected cattle, production records, rations and post-mortem results led investigators to conclude that a variant of Clostridium perfringens, specifically type A, should be considered further as a possible cause of this disease syndrome. Recommendations for investigation of a problem herd are discussed. Specific items of increased risk in this particular herd included an association between increased milk production and death loss, an increased incidence rate associated with higher soluble carbohydrate feeding rates, and disease following re-introduction of culture-positive alfalfa haylage. There appear to be gut motility aberrations, evidenced by intussusceptions in tandem with Jejunal Haemorrhage Syndrome lesions.

Dual infection with enterotoxigenic Escherichia coli and porcine reproductive and respiratory syndrome virus observed in weaning pigs that died suddenly.

Diarrhea, sudden death after short duration of diarrhea and sudden death without apparent signs were observed in a herd of breeder pigs. Five pigs that died suddenly with diarrhea (SDD pigs) and 6 pigs that died suddenly without signs (SD pigs) were examined. The average age of the pigs was about 28 days. Twelve pigs of age 10 to 14 days old showing diarrhea (D pigs) were also examined. Eleven of them recovered. Large numbers of Escherichia coli were detected in all organs of every SDD and SD pig and in feces of D pigs. All of the isolates were identified as enterotoxigenic E. coli (ETEC) by the polymerase chain reaction (PCR). Porcine reproductive and respiratory syndrome (PRRS) virus cDNA was also detected from the lung of every SD and SDD pig by the RT-PCR. High and low titers of antibodies to PRRS virus were found in 10-day-old and 1-month-old pigs, respectively. In an experiment, 3 ETEC were isolated from 9 healthy weaning pigs during the quiescent stage in the herd. These data showed that growth of the ETEC was not active in healthy weaning pigs; however, following infection with PRRS virus ETEC infection became systemic and caused peracute death in the weaning pigs. It suggested also that infection with PRRS virus in 10-day-old pigs were protected by the colostral antibodies, and fatal infection by ETEC did not occur as a result.

Macrophage subtype patterns in protracted asphyxiation.

The question was examined whether protracted asphyxiation is associated with a distinct macrophage subtype pattern in lung tissue. Immunohistochemical preparations of lung specimens were tested with the antibodies MRP8, MRP14, 27E10 and 25F9 in cases of protracted asphyxiation (n = 8) and in "control" groups (hanging: n = 6; peracute deaths: n = 9). MRP8 and MRP14 interstitial cell counts showed a doubling in protracted asphyxiation. Furthermore, clear increases of 27E10 and 25F9 cells (intravascular and interstitial) were found in protracted asphyxiation, both in the intravascular and interstitial compartments. At present the results look promising as to an additional diagnostic criterion for the differential diagnosis between acute and protracted asphyxiation.

Effect of chemical sympathectomy on the neural spread of pseudorabies virus in mice

To investigate the routes of neural spread of pseudorabies (Aujeszky's disease) virus (PRV), the effects of chemical sympathectomy by 6-hydroxydopamine (6-OHDA) on clinical signs and viral spread in mice inoculated intraocularly with PRV were examined. Similar to non-treated mice, the treated mice developed pruritus as a major clinical sign, followed by peracute death, but the time of death tended to be slightly delayed in about half of the treated mice. On immunohistological examination, viral antigens in treated mice were found to be markedly reduced in all the ipsilateral retinae; they were detected diffusely in the forebrain area with a localization in the mammillary area. In the treated mice, viral antigens were also reduced in the ipsilateral trigeminal nerve ganglia as well as in its central nuclei. These findings indicate that both the sympathetic nervous system and the trigeminal nervous system play an important role in the neural spread of PRV. Possible involvement of the dopaminergic nervous system, particularly in the eye, as the main site of viral growth was discussed.