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Query: UMLS:C0012739 (disseminated intravascular coagulation)
 8,673 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rhesus monkeys inoculated intravenously with Rift Valley fever (RVF) virus presented clinical disease syndromes similar to human cases of RVF. All 17 infected monkeys had high-titered viremias but disease ranged from clinically inapparent to death. Three (18%) RVF virus-infected monkeys developed signs of hemorrhagic fever characterized by epistaxis, petechial to purpuric cutaneous lesions, anorexia, and vomiting prior to death. The 14 remaining monkeys survived RVF viral infection but, 7 showed clinical signs of illness characterized by diminished food intake, cutaneous petechiae, and occasional vomiting. The other 7 monkeys showed no evidence of clinical disease. All monkeys had detectable serum interferon 24-30 h after infection, but 4 of 7 monkeys that did not develop clinical illness had serum interferon titers within 12 h after infection. In lethally infected macaques, indices of hepatic function and blood coagulation were abnormal within 2 days, implicating early pathogenetic events as critical determinants of survival. Serum transferase values were elevated in proportion to severity of clinical disease and outcome of infection. Both myocardial damage and laboratory evidence consistent with disseminated intravascular coagulation were present in fatal infections. All surviving monkeys developed neutralizing antibodies to RVF virus 4-7 days after infection, and this coincided with termination of viremia. Two fatally infected monkeys were viremic until death on days 6 and 8, and the third cleared viremia on day 5 and developed antibody on day 6 but died on day 15. There was a significant correlation between a delayed interferon response and mortality, suggesting that the early appearance of interferon was influential in limiting the severity of disease.
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PMID:Pathogenesis of Rift Valley fever in rhesus monkeys: role of interferon response. 169 May 34

The hamster, Mesocricetus auratus, was examined as a possible model for investigating the poorly defined pathogenesis of the family Bunyaviridae, genus Phlebovirus. Punta Toro virus (PTV) isolates from Eastern Panama were highly virulent for two outbred and five inbred hamster strains, while isolates from western Panama were of low virulence. The Adames strain (eastern Panama) of PTV (LD50 approximately 1 PFU, sc) caused an acute fatal disease (average survival time, 3.8 days) in 10-week-old Lak: LVG (SYR) hamsters. Severe necrosis of the liver, spleen, and small intestine was associated with extensive expression of viral antigen in these organs. The Balliet strain (western Panama) of PTV (LD50 greater than 6 log10 PFU, subcutaneously) caused a mild hepatocellular infection with peak viral liver titers of 3-4 log10 PFU/g compared to 8-9 log10 PFU/g for the Adames strain. We observed histological lesions in the red pulp of the spleen or the lamina propria of the small intestine with the Adames strain. Lesions in the hamsters had characteristics of disseminated intravascular coagulation (DIC). The PTV-hamster model shares similarities to Rift Valley fever (phleboviral disease), which causes fatal disease in man and domesticated ruminants.
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PMID:Pathogenesis of a phleboviral infection (Punta Toro virus) in golden Syrian hamsters. 212 75

Although many viral infections have on occasion been associated with hemorrhagic complications, infection with any of several RNA viruses regularly results in vascular involvement and the syndrome called viral hemorrhagic fever (VHF). In spite of clinically useful similarities among various VHFs, there are significant differences in their pathogenesis and clinical evolution; these are often related to characteristics of their viral taxon. Infection with Rift Valley fever (RVF) virus, a phlebovirus, appears to be regulated by interferon and terminated by neutralizing antibody. In contrast, Lassa fever (LF) virus, an arenavirus, is resistant to interferon, and LF is terminated by cellular immune effector mechanisms. The lytic virus-cell interaction typical of RVF virus suggests its major effects occur by direct, virus-induced cellular necrosis, particularly in the liver. In the primate RVF model, disseminated intravascular coagulation (DIC) may be important. LF virus--characteristically noncytopathic--may exert its effects through induction of mediator secretion from infected macrophages. DIC does not appear to be a central pathogenetic mechanism in LF. Pichinde virus, which is not pathogenic for humans, provides an alternate model for study of LF. Infected guinea pigs do not show histologic lesions that could explain their body wasting, cardiovascular deterioration, and pulmonary edema. In the heart, for example, loss of tissue mass, protein, and contractile function proceed without direct viral involvement or myocarditis. Sulfidopeptide leukotrienes have been implicated as one relevant soluble mediator participating in the disease state.
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PMID:Pathogenesis of viral hemorrhagic fevers: Rift Valley fever and Lassa fever contrasted. 266 11

Rift Valley fever (RVF) is an important cause of disease in animals and humans in sub-Saharan Africa. In a small percentage of human cases, the disease is complicated by hemorrhage, which often is associated with a fatal outcome. Inoculation of rhesus monkeys with the Zagazig Hospital strain of RVF virus produced a clinical picture similar to illness in humans. Ten of 17 monkeys developed clinical evidence of hemostatic impairment. When coagulation tests were performed, this group of monkeys had significant abnormalities, including evidence for disseminated intravascular coagulation. These abnormalities were much less pronounced in the remaining seven monkeys-whose only sign of illness was transient fever-and, in general, they paralleled the level of viremia and the degree of elevation in levels of serum hepatic enzymes. Autopsy of the three monkeys with severe disease revealed hepatic necrosis.
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PMID:Hemostatic derangement produced by Rift Valley fever virus in rhesus monkeys. 274 12

Infection rates were compared in Culex pipiens and Aedes taeniorhynchus after they fed on Rift Valley fever (RVF) viremic hamsters or ingested similar doses of RVF virus from blood-soaked pledgets. Infection rates were significantly lower for mosquitoes that ingested virus from a pledget than for those that ingested similar doses from viremic hamsters. The method used to prevent normal clot formation for the pledget feedings (i.e., defibrination by shaking with glass beads or addition of heparin) did not affect subsequent infection rates. Both inhibition of normal clot formation and freezing of virus after it had last been propagated were associated with significantly reduced infection rates with the pledget feedings. Laboratory studies using artificial feeding techniques may not give reliable estimates of the vector competence of mosquitoes for arboviruses.
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PMID:Reduced Rift Valley fever virus infection rates in mosquitoes associated with pledget feedings. 320 78

Rift Valley fever (RVF) is a major cause of human morbidity and mortality in endemic areas of sub-Saharan Africa and has the potential to cause epidemic disease in receptive areas world-wide. In this study, a RVF viral isolate from the 1977 Egyptian epidemic (ZH-501) inoculated intravenously into rhesus macaques caused a benign viremic infection in most, but resulted in the hemorrhagic fever syndrome in 20 per cent (3 of 15). Serious disease of this type has not previously been observed in nonhuman primates inoculated with RVF virus and may be a consequence of the viral strain used or the route of inoculation. Severe disease was accompanied by extensive liver necrosis, disseminated intravascular coagulation, and microangiopathic hemolytic anemia. We also attempted to prevent RVF by passive transfer of serum from vaccinated rhesus monkeys (plaque-reduction neutralization test titer 1:2,560). As little as 0.025 ml/kg prevented the development of viremia in naive rhesus monkeys after subcutaneous inoculation of virus. The monkey model should be helpful in understanding the pathogenesis and prevention of human RVF.
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PMID:Experimental Rift Valley fever in rhesus macaques. 335 74

Experimental infection of three indigenous breeds of sheep in Nigeria, namely the West African Dwarf (WAD), Yankasa and Ouda resulted in fatal disease with the Zinga Rift Valley Fever virus. Infected sheep of the three breeds responded by pyrexia within 24 h of infection, that lasted 6 to 7 days, but peaked between day 2 and 4 post-infection. Viraemia coincided with pyrexia and peaked (10(9) PFU/ml) 3 days p.i. in Yankasa and WAD sheep, but with highest titre (10(7.5) PFU/ml) in Ouda sheep. Zinga Rift Valley Fever virus infection of sheep was characterised by hyperactivity, watery and mucoid nasal discharges, projectiles and bloody diarrhoea, external haemorrhage and clinical manifestations of nervous disorders. Viraemia was followed by low level of antibody development in all the infected sheep. Haemotological changes included a sharp fall in the PCV, Hb concentration and total RBC count during the course of the disease. These changes were most severe in the Yankasa, followed by WAD and Ouda breeds. There were thrombocytopaenia, prolongation of prothrombin and clotting times in all the infected sheep. There was also progressive leucopaenia associated with lymphopaenia. The total protein and albumin levels were depressed, but the globulin level rose from day 5 p.i. The changes in the serum biochemical constituents included sharp and progressive increase in the level of alanine aminotransferase and aspartate aminotransferase. The sodium level decreased gradually while that of potassium was initially stable but later increased until the infected animals died. There was a significant increase in the level of blood urea nitrogen from day 3 p.i. that continued until the infected animals died. Gross and microscopic examinations of the carcasses of the infected sheep showed significant lesions in many organs, including disseminated intravascular coagulation.
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PMID:Experimental infection of three Nigerian breeds of sheep with the Zinga strain of the Rift Valley Fever virus. 888 13

On September 10, 2000, the Ministry of Health (MOH), Kingdom of Saudi Arabia, and subsequently the Ministry of Health of Yemen received reports of unexplained hemorrhagic fever in humans and associated animal deaths from the southwestern border of Saudi Arabia and Yemen. Signs and symptoms of ill persons included low grade fever, abdominal pain, vomiting, diarrhea, jaundice with liver and renal dysfunction often progressing to disseminated intravascular coagulation, hepatorenal syndrome, and death. On September 15, using ELISA (antigen detection and IgM), polymerase chain reaction, virus isolation, and immunohistochemistry, CDC confirmed the diagnosis of Rift Valley fever (RVF) in all four serum samples submitted from Saudi Arabia. This report summarizes the preliminary results of the collaborative epidemiologic investigation performed by the Saudi Arabian MOH, CDC, and the National Institute of Virology, South Africa, of the first confirmed occurrence of RVF outside Africa.
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PMID:Outbreak of Rift Valley fever--Saudi Arabia, August-October, 2000. 1104 43