Clinical Signs Of Illness Research Articles

Distribution of Pasteurella haemolytica in the respiratory tracts of carrier calves and those subsequently infected experimentally with Dictyocaulus viviparus

Distribution of Pasteurella haemolytica in the respiratory tracts of calves with no apparent clinical signs of illness and those infected experimentally with Dictyocaulus viviparus was determined so as to define carrier sites for this organism. The calves had been positive by nasopharyngeal swab for either P haemolytica A2 or A1 for at least two months or for over a month, respectively, before slaughter. P haemolytica A1 was acquired following horizontal spread from other infected calves. It was observed post mortem that P haemolytica A1 or A2 resided in the tonsils and retropharyngeal lymph nodes of calves of both groups. In addition to these sites, P haemolytica A1 was also isolated from the right cranial lung lobe of one of the calves from the D viviparus infected group although there was no evidence of pasteurella associated pneumonia. It was concluded that tonsil and retropharyngeal lymph nodes appear to be the most important carrier sites for P haemolytica when compared to other tissues of the bovine respiratory tract.

Long latency event‐related potentials in patients infected with human immunodeficiency virus

Long latency auditory evoked potentials were recorded in 55 homosexual men infected with human immunodeficiency virus (HIV). Forty-one of these patients were asymptomatic from the infection and 14 had clinical signs of illness. Nine of the symptomatic patients were demented and 8 (6 of whom were demented) met other diagnostic criteria for acquired immunodeficiency syndrome (AIDS). Cerebral responses were recorded from Fz, Cz, and Pz electrode placements referred to linked mastoids and averaged separately to rare (2,000 Hz) and frequent (1,000 Hz) tones presented in a pseudorandom sequence. Electroencephalography (EEG) was performed in 54 of the patients and magnetic resonance imaging (MRI) or computed tomography (CT) was done in 14 (13 of whom were symptomatic from the infection). The latency of N1, P2, N2, and P3 components was delayed in HIV-positive patients compared to normal and this was particularly so for the N1, N2, and P3 components. These changes were more marked in those patients who were symptomatic from their infection, especially in those who were demented. They were, however, present to a lesser degree even in asymptomatic (Class II) patients. Thus, 78% of the demented patients and 28% of nondemented patients had a delay in latency of at least one of the evoked potential components beyond the upper limit of our normal population. By contrast, the EEG was normal in all patients with asymptomatic HIV infection and most symptomatic patients, although 5 patients in this latter group had mild generalized slowing. MRI and CT findings were similarly nonspecific, particularly in the nondemented group.(ABSTRACT TRUNCATED AT 250 WORDS)

Virus safe plasma proteins: Elimination of the viruses of risk by the manufacturing procedure

Each infusion of blood or human plasma derivatives -especially of coagulation factor concentrates-in principle involves the risk of transmission of viral infection, unless measures are taken to eliminate this risk. Owing to the present state of our scientific knowledge, the elimination of the risk of infection is possible, not for blood, but for plasma derivatives since, in the latter case, virusinactivating steps can be incorporated into the manufacturing process. The infectious agents potentially occurring in plasma derivatives are limited to viruses since, in each production process, bacteria and parasites are completely removed by sterile filtration. Of the viruses, only those play a role which occur in the blood of donors without clinical signs of illness and which are not generally neutralized and eliminated by corresponding antibodies in the plasma pool. Exactly which viruses are involved is a question which is best answered by reference to retrospective clinical studies in haemophiliacs since these patients are treated repeatedly, often throughout their lives with Factor VIII concentrates or antihaemophilic cryoprecipitate. The risk of infection of these patients may be small but is cumulatively increased by the

Recent trends in human leptospirosis in Italy.

The recent epidemiological trends of human leptospirosis in Italy were investigated using data collected for the years 1981-1985. A total of 626 hospitalized patients with clinical diagnoses of suspected leptospirosis were reported by hospital centers from several Italian regions. Epidemiological, clinical and seroimmunological data were collected in 517 of these cases and examined by the National Center for Leptospirosis. Serological findings in 33.5% of these subjects met the criteria for confirmation of the disease. In 21.8% of the subjects, low titer antibodies were detected, which possibly reflected previous leptospiral infections. An early antibiotic treatment of the current infection may also have lowered the seroimmunological response in some of these patients. In 59.3% of the confirmed cases, modes of transmission were allotted equally between accidental events and recreational or occupational activities. Drinking water from an open air fountain emerged as an uncommon mode of transmission; it was responsible for an outbreak of 33 cases of leptospirosis. In another 37.07% of the subjects, it was impossible to establish the mode of transmission. Respiratory or influenza-like symptoms were the only clinical signs of illness in 21.2% of the patients with confirmed leptospirosis. In comparison to the sixties and seventies, the prevalence of infecting serovars showed increasing incidence of infections due to serovars of the Javanica (11.0%) and Australis (11.0%) serogroups and an important decrease in the Bataviae serogroup infections (from 58.8% in rice-field workers in the forties to 0.6% in the years 1981-1985). Sejroe serogroup infections accounted for 4.5 per cent of confirmed cases of leptospirosis.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of experimentally induced respiratory virus infections on performance.

Studies of experimentally induced respiratory infections and illnesses showed that influenza impaired performance on a visual search task but had no effect on a simple motor task, whereas colds impaired the motor task but not the search task. The effect of influenza on the search task was observed in both volunteers with significant clinical symptoms and volunteers who were shown, by virological techniques, to be infected but who had no significant clinical illness. Performance was also impaired during the incubation period of this illness, which confirms that subclinical influenza virus infections can have behavioural effects. In contrast to influenza, the effects of colds were restricted to volunteers who had significant clinical symptoms, and the impairments in performance were observed only when the symptoms were apparent.

Evidence of hepatitis A infection in immature rhesus monkeys.

Forty immature (less than 2 years old) rhesus monkeys (Macaca mulatta) with marked increases in aspartate and alanine aminotransferase activities were examined. Serological and histopathological evaluations were done to determine if affected animals were infected with hepatitis A virus. Although no clinical signs of illness were noted in any of the monkeys, an excellent correlation was found between the increased serum aminotransferase values and seropositivity with the acute phase (IgM) HAVAB-M antibody. Histopathological evaluations of livers of selected animals revealed hepatic lesions consistent with those in chimpanzees and marmosets infected with hepatitis A virus: generalized activation of sinusoidal lining cells, focal hepatocellular necrosis with occasional acidophilic bodies, and cuffs of mononuclear cells in the portal areas. Although no animals were seropositive for HAVAB upon receipt from the breeding colony, a total of ten of 18 animals for which serological data were available had seroconverted to HAVAB positivity during the 4-month observation period. These results are consistent with hepatitis A infection in immature rhesus monkeys and indicate the potential significance of serological testing in animals in which hepatic function is being evaluated.

Experimental infections of Anaplasma ovis in pronghorn antelope.

Anaplasma ovis was experimentally transmitted from sheep to pronghorn antelope (Antilocapra americana) and back to sheep. Anaplasma ovis was recovered in splenectomized sheep, from two of three spleen-intact pronghorns following their inoculation with blood from known A. ovis carrier sheep. These two pronghorns exhibited a 0.5% or higher A. ovis parasitemia within 48 days after exposure, and an anaplasmosis-positive serological response 91 days after exposure. Clinical signs of illness were not observed. Blood from the infected pronghorns produced disease in four splenectomized sheep.

Effects of Experimentally Induced Respiratory Virus Infections and Illness on Psychomotor Performance

In two studies experimentally induced colds slowed the speed of response in a serial reaction task. Responding was also slower during the incubation period of the illness, which shows that performance on such a task may be used to predict subsequent illness. Volunteers who had no significant clinical illness, but who had a significant rise in IgG following virus challenge, also showed changes in performance. In contrast to the serial reaction task, neither colds nor subclinical infections impaired performance on a detection task.

Recovery of dual serotypes of bluetongue virus from infected sheep and cattle

Dual serotypes of bluetongue virus (BTV) were recovered from field-collected samples of sheep and cattle blood. Two sheep, each infected with both BTV serotypes 10 and 17, were found in a flock with bluetongue disease associated with these two serotypes. One sheep infected with BTV serotypes 11 and 17 was found in a second flock; it was the only viremic sheep detected and was clinically ill. Dual serotype infections of one beef and two dairy cattle were found in three geographically separate herds; mixtures recovered were of BTV serotypes 10 and 17 and serotypes 11 and 17. Clinical signs of illness were absent in the cattle in two herds, but severe conjuctivitis was seen in several cows in a third herd, including the cow with a dual serotype infection (BTV 11 and 17). Two of the cattle with dual infections had no serological evidence of BTV as determined by the agar gel precipitin test; serum was not available from the other cow with a dual serotype infection. The significance of dual infections and immune tolerance are discussed.

Sarcocystis idahoensis sp. n. in deer mice Peromyscus maniculatus (Wagner) and gopher snakes Pituophis melanoleucus (Daudin).

SYNOPSIS Deer mice Peromyscus maniculatus (Wagner) were trapped near Hammett, Idaho, as a possible source of Besnoitia jellisoni Frenkel and species of Sarcocystis to be used for life cycle studies. Forty‐nine deer mice were necropsied; 20 (40.8%) were positive for sarcocysts structurally identical with those of Sarcocystis idahoensis sp. N. the source of S. idahoensis used for life cycle studies was a Great Basin gopher snake Pituophis melanoleucus deserticola Stejneger killed near Hammett, Idaho; 20 sporulated sporocysts measured 11.1 × 13.4 (11‐12 × 13‐14) μm. Structurally identical sporocysts were found in 7 of 14 Pacific gopher snakes P. m. catenifer (Blainville), and in 6 of 10 San Diego gopher snakes, P. m. annectens Baird & Girard. Totals of 148 deer mice and 17 gopher snakes were necropsied in the course of life cycle studies. Development of the first generation meronts took place within the hepatocytes of deer mice 2‐10 days post‐inoculation (PI) with sporulated sporocysts. Rosette‐shaped meronts (6‐8 days PI) contained tachyzoites attached by their posterior poles to a residual body. After release from the residual body, tachyzoites were initially retained in a meront wall and later released from the hot cells Within muscle cells a single tachyzoite‐shaped structure was found 11 days PI and PAS‐negative metrocyte‐containing sarcocysts (2nd generation meronts) 13‐34 days PI. PAS‐positive material was first seen in sarcocysts 34 days II at which time bradyzoite formation became apparent. At 160 days PI, 10 sarcocysts measured 0.4 × 5.8 (0.2‐0.9 × 1.8‐9.9) μ and appeared to be mature and structurally identical with those from naturally infected deer mice. After ingestion of S. idahoensis‐infected deer mice by gopher snakes, bradyzoites developed directly into microgamonts and macrogametes. These stages were first seen 5 days PI. Microgamonts were generally located above and macrogametes below the epithelial host cell nucleus. Seven to 11 days PI microgamonts were seen with mature microgametes, and oocysts which had not yet begun sporogony were found with oocyst walls. Clinical signs of illness were generally not observed in infected gopher snakes; however, one snake developed anorexia and cachexia, and became moribund after repeated ingestion of heavily infected deer mice. Acute hepatitis associated with developing meronts often was noted in deer mice given over 15,000 sporocysts each. Five to 6 days PI anorexia, weakness, ataxia, and dyspnea were observed: these clinical signs increased in severity until 6‐8 days PI, when mice became recumbent and died, or were killed while moribund. Hepatosplenomegaly, petechial hemorrhage o the serosal and cut surfaces of the liver, and icterus were common. Diffuse coagulative necrosis with cellular infiltration (primarily neutrophils) was noted on microscopic examination.

Reaction of red deer ( Cervus elaphus L.) hinds to removal of their suckled calves for hand-rearing

Four calves, aged from 3 h to 8 days, were taken from their dams on hill grazings and removed for hand-rearing. The hinds were observed closely. Appetite remained good. The udeers, after some initial increase in size which did not appear to cause discomfort, regressed satisfactorily. An impression of some restles ness and enquiry after their calves was gained; but “calling” was not heard after the first 30 h. There was no noticeable change in individual temperament of hinds. There were no clinical signs of illness. It appeared that the effects on these dams, of removing their calves, were acceptable on health and welfare grounds.

Experimental Milk-Borne Transmission of Powassan Virus in the Goat

A lactating goat with a 74-day-old kid was inoculated with 10(3) mouse 50% lethal dose (LD50) of Powassan virus. No ensuing viremia could be detected, but virus was secreted in the milk on postinoculation days 7 through 15, with a titer of 10(5) LD50/ml on day 12. Neutralizing antibody was found in the serum on days 22 through 36 and in the milk on day 36. The offspring was not inoculated but was allowed to continue feeding on its mother's milk. It developed neutralizing antibody by day 22. Since the kid was past the age when it could resorb antibody from the milk, its serum antibody was evidence of active infection. Neither animal showed any clinical sign of illness. A serum survey of 499 goats in New York State showed that 9 had neutralizing antibodies to Powassan virus. These immune goats came from widely scattered localities, including counties where human cases have been confirmed. The findings suggest the possibility of milk-borne transmission of Powassan virus from goat to man.

Cytomegalovirus: Clinical virological correlations in renal transplant recipients.

One-hundred thirty-two renal transplant recipients were systematically screened for viral infections and the findings correlated with the clinical course. One-hundred ten patients showed evidence of infection with herpesviruses and 89 patients showed laboratory evidence of infection with cytomegalovirus (CMV) uncomplicated by bacterial infections or technical complications. Patients without viral infections were usually asymptomatic. After recovery and development of anti-viral antibodies, most patients were asymptomatic despite the persistence of viral excretion in the urine. In contrast, the onset of viral infections were almost always accompanied by a significant clinical illness characterized by fever, leukopenia, and renal malfunction. Of 89 patients with cytomegalovirus infections, 83 survived at least three months. In these patients, the fever appeared to be self-limited and resolution of the fever was accompanied by increases in anti-CMV antibody. Renal biopsies demonstrated typical rejection reactions in all the biopsied patients and renal malfunction usually responded to anti-rejection treatment. Six of the 89 patients with CMV infections died within a month of viral isolation. These patients could be distinguished from those who recovered by a decreased or absent antibody response to the virus, suppressed lymphocyte responses to mitogen in autochthonous blood, and absent histologic evidence of rejection in the renal allografts. Thus, two paradoxical responses to CMV infections are seen in transplant patients: In the relatively immunocompetent patient, the infection is associated with renal allograft rejection, a prompt antibody response to the virus, and recovery. The severely immunosuppressed patient cannot make an antibody response, does not exhibit allograft rejection as a cause of renal malfunction, he may be further immunosuppressed by the viral infection, and is susceptible to sequential opportunistic infections leading to death.

Protracted and recurrent forms of viral hepatitis.

The majority of patients with clinically recognizable virus hepatitis recover. Varying degrees of liver damage persists in a few. However, the lack of knowledge of factors responsible for the persistence of the stimulates continued interest in the sequelae of hepatitis. The different forms of chronic hepatitis, 1-3 the normal course of hepatitis, 4,5 and the prolonged forms 6-9 must be defined. Chronic hepatitis is now classified from the pathological point of view as chronic persistent hepatitis and chronic aggressive hepatitis. 10 The latter is divided into a moderate and a more aggressive form. Chronic persistent hepatitis is characterized by lymphoid cell infiltration of portal tracts, sometimes with slight fibrosis, but sharp border lines of lobules and normal liver architecture. The main complaint is fatigue. In some cases there are no clinical signs of illness. Slight enlargement of the liver is present, transaminase values are elevated, sulfobromophthalein (Bromsulphalein [BSP]) retention is

Production of advanced coronary atherosclerosis, myocardial infarction and “sudden death” in swine

The purpose of this study was to develop a model in swine for advanced coronary atherosclerosis and myocardial infarction. The approach was to combine a number of techniques that were thought to induce the development of atherosclerosis, including high-fat, high-cholesterol diets plus propylthiouracil and X-irradiation to the precordial region. The dose of X-irradiation that was used produced no significant changes by itself, but seemed only to enhance the effect of atherogenic diets. Among 28 swine fed the severe atherogenic diet and X-irradiated twice, 24 developed myocardial infarcts. All had advanced coronary atherosclerosis. Many died “suddenly” in the sense that no clinical signs of illness were observed prior to death. Coronary angiography was done on some swine and direct measurements of coronary blood flow on a few others. Coronary atherosclerosis and myocardial infarction were also produced in a few swine without propylthiouracil using a combination of a high-fat, high-cholesterol diet and X-irradiation.

The Clinical Aspects of Rift Valley Fever Virus in Household Pets: II. Susceptibility of the Cat

Abstract : The dog was shown to be susceptible to Rift Valley fever virus (RVFV) . Death occurred in all animals of 1 and 7 days of age inoculated with 1 x 10 to the 2.2 power MICLD50 or more of virus, and two of four puppies died following inoculation with 1 x 10 to the 0.2 power MICLD50 of virus. Temperature at death was hypothermic. Older animals, although susceptible, were not killed by RVFV; there were no signs of clinical illness, although 50% of adult dogs developed a viremia. All animals with a positive viremia demonstrated a positive serum neutralization titer. Transmission of RVFV from pup to mother and from pup to pup was demonstrated. There was evidence that antibodies were passed from mother to pup in the colostrum. The data suggest an effect on fertility. The epidemiological aspects of this study are discussed. (Author)

The clinical aspects of Rift Valley Fever virus in household pets. I. Susceptibility of the dog.

Abstract : The dog was shown to be susceptible to Rift Valley fever virus (RVFV) . Death occurred in all animals of 1 and 7 days of age inoculated with 1 x 10 to the 2.2 power MICLD50 or more of virus, and two of four puppies died following inoculation with 1 x 10 to the 0.2 power MICLD50 of virus. Temperature at death was hypothermic. Older animals, although susceptible, were not killed by RVFV; there were no signs of clinical illness, although 50% of adult dogs developed a viremia. All animals with a positive viremia demonstrated a positive serum neutralization titer. Transmission of RVFV from pup to mother and from pup to pup was demonstrated. There was evidence that antibodies were passed from mother to pup in the colostrum. The data suggest an effect on fertility. The epidemiological aspects of this study are discussed. (Author)

Pathology of oxygen toxicity in forty Macaca mulatta. AMRL-TR-66-234.

Abstract : Forty monkeys (Macaca mulatta) were exposed to 99-100% oxygen at pressures from 600 to 760 mm Hg. The acute exudative pulmonary response was seen in only three exposed at 760 mm Hg. The subacute proliferative pulmonary response was seen at all levels studied, the degree being directly related to time-dose exposures. In the high dose ranges clinical signs of illness were evident after 5-7 days exposure when the monkeys became listless and anoretic. By 14 days they were quite lethargic and had assumed a huddled position. Grossly, the heavy lungs had a gray, bloodless appearance. Microscopically, there was extreme proliferation of the interstitium and alveolar epithelium. None of the monkeys that were exposed at 600 mm Hg died, although mild focal proliferative changes were seen. After 31 days postexposure, these changes appeared as focal areas of atelectasis with mild septal fibrosis.

AEROSOL EXPOSURE OF MONKEYS TO INFLUENZA VIRUS.

Discussion and summaryPrevious studies from this laboratory(1) showed that intratracheal inoculation of rhesus monkeys with the PR8 strain of influenza virus resulted in mild illness in 2 of 4 monkeys; after intranasal inoculation, no clinical signs of illness were observed. Results of studies by others (2–5) have varied with the influenza virus strain and monkey species employed. In all, virus was administered intratracheally or intranasally, and in general, clinical evidence of disease was minimal or absent.The development of quantitative procedures for exposure of experimental animals to aerosols of infective organisms(6) suggested reinvestigation of the response of monkeys following challenge with influenza virus by these methods. The present report describes the clinical, hematologic and serologic response of rhesus and cynomolgus monkeys after aerosol exposure to the PR8 strain of influenza virus.Materials and methods. Challenge of young adult monkeys, Macaca mulatta and M. irus, was conducted in a ...

Administration of an Attenuated Type I Poliomyelitis Virus to Human Subjects

SummaryTwo human subjects who had no antibodies against Type I poliomyelitis virus were fed a mouse adapted Type I strain, and one human subject who had no antibodies against Types I and II was fed a mixture of mouse adapted Type I and Type II strains. None of the individuals showed clinical signs of illness as a result of ingestion of the virus. In the absence of viremia, all 3 excreted virus in the stools. Homologous neutralizing antibodies developed in the sera of each person. Virus passaged through the human intestinal tract maintained the very low pathogenicity for monkeys when injected intracerebrally.