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A two year old Thoroughbred colt was presented after a clinical diagnosis of right sided laryngeal hemiplegia had been made. On endoscopic examination the right arytenoid cartilage was immobile during respiration while the left moved normally. Post-mortem examination revealed an abnormal shape of the cricoid and thyroid cartilages which resulted in absence of the right cricothyroid articulation. The defect was thought to be congenital in origin.

From October 1981 to September 1984, the authors conducted a three-year longitudinal study of diarrhea among infants and toddlers attending day care centers in Maricopa County, Arizona. In the third year of study, they evaluated the effects on diarrhea rates of staff training without external monitoring and of active surveillance conducted throughout the study. From 21 study day care centers, they randomly selected 10 ("intervention day care centers") to receive staff training in procedures to reduce transmission of infectious diarrhea. Continuing active surveillance in the 10 intervention and 11 control day care centers found no difference between diarrhea rates in intervention day care centers in the pre- and posttraining years and no difference between diarrhea rates in the two groups of centers either before or after the training intervention. Biweekly family-based surveys during the two months after training also demonstrated no difference between infant-toddler diarrhea rates in intervention and control day care centers. These surveys found the 21 study day care centers to have significantly higher diarrhea rates than did day care homes or households not using day care, but significantly lower rates than day care centers not included in the active surveillance. Continuous surveillance without training was associated with a significant decrease in diarrheal illness during the course of longitudinal study. One-time staff training without subsequent monitoring did not result in additional decreases and did not lower day care center diarrhea rates to the levels observed in day care homes and households not using day care.

Thirty-eight cases of human rabies occurred in the United States and its territories from 1960 to 1979. The major source of exposure to rabies has changed from indigenous dogs and cats in the 1940s and 1950s to wild carnivores and bats (11 of the 27 cases with known exposures); unusual exposures (3 cases) and exposures in a foreign country (7 cases) have also become more important. No exposure could be identified for 6 of the 38 cases. Two patients received optimal prophylaxis, 14 suboptimal, and 22 no prophylaxis after exposure. Some cases might have been prevented by an increased awareness of the risks and treatment for exposure to rabies, and use of the new rabies vaccines. The diagnosis was often made late in the clinical course including after death in 8 cases. This delay, in part, resulted from the diversity in the clinical presentation. Rabies should be considered in any case of encephalitis or myelitis. Laboratory confirmation of the diagnosis was often delayed. Testing for serum antibodies was the most reliable test in unvaccinated patients, and isolation of virus was the test most likely to be positive early in the illness.

A five-year-old Border Collie bitch was presented to Massey University Small Animal Clinic, for examination of a right forelimb lameness of three months duration. The distal forelimb was deviated laterally, there was limited mobility of the shoulder joint, and the animal showed gait abnormalities. Marked atrophy of the infraspinatus, supraspinatus and deltoideus muscles were present. Contracture of the infraspinatus muscle caused the lameness, and tenotomy of the infraspinatus tendon resulted in restoration of a normal gait. Although the exact aetiology is unknown, several possibilities are discussed.

The process of erythropoiesis and vasculogenesis in the yolk sac of the bat (Tadarida brasiliensis cynocephala) has been studied through the use of both light and electron microscopy. Stem cells arise from the leading edge of the migrating splanchnic mesoderm and transform into primitive erythroblasts. Differentiation involves either contact or association with the endodermal cells, since all erythropoietic activity occurs on the endodermal side of the expanding vascular bed, and many of the cells are in close apposition to the lateral or basal plasma membranes of the endodermal cells. Endodermal cells also phagocytize developing primitive erythroblasts during the later stage of the process when erythropoiesis is subsiding in the yolk sac. Cells destined to become the endothelium of the expanding vascular bed also arise from the leading edge of the migrating splanchnic mesoderm. Their process of differentiation involves the development of cytoplasmic extensions that may surround a group of differentiating erythroblasts, enclosing them in the newly formed lumen of the blood vessel. The cytoplasmic extensions make contact and develop junctional complexes with similar processes from other cells to complete the lumen of the lengthening vascular bed. Cells of the granulocyte series or megakaryocytes are not observed in the yolk sac of the bat as has been described in certain other species.

Acute respiratory illness is one of the leading causes of childhood mortality in developing nations. We investigated an increase in hospitalizations of children less than 2 years old for severe lower respiratory tract illness (LRI) from October 1986 through December 1986 on the island of American Samoa. Hospitalization rates were highest in children less than 6 months of age (60 of 1000 compared with 22 of 1000 for those 6 to 11 months of age, and seven of 1000 for those 12 to 24 months of age). The outbreak was more severe than in previous years, with ten (19%) of 54 patients admitted to the intensive care unit (ICU) compared with three (7%) of 42 and one (3%) of 40 during the same months of 1985 and 1984. Two patients died. Most patients had clinical bronchiolitis; of 34 patients tested, serologic or nasal aspirate evidence of recent respiratory syncytial virus (RSV) infection was found in 18 (53%). A study of patients younger than 1 year of age demonstrated that patients hospitalized with LRI were more likely to have a household member who smoked cigarettes (18/20, 90%) than outpatient controls without recent respiratory illness (8/15, 53%). Maternal sera obtained between December 1985 and October 1986 showed no protective effect of either detectable IgG or neutralizing antibody to two major groups of RSV. Our study documents the involvement of RSV in an outbreak of severe LRI among infants in a tropical area and further suggests that exposure to cigarette smoke is a risk factor for LRI infants.

The purpose of the present study was to identify the proliferative cell types in the nonciliated cell population of the upper airways and determine the capacity of each to act as progenitor cells. Sprague-Dawley rats (30 days old) were exposed to 20 ppm NO2 for 24 hours to stimulate cell division, given injected tritiated thymidine (3H-TdR), sacrificed 1 hour and 1, 3, 5, and 7 days later, and prepared for light- and electron-microscopic autoradiography. One hour after injection of 3H-TdR, the mean labeling index (LI) was 1.6% in control animals and 5.2% in exposed animals. Mean grain counts per cell decreased from 15.6 at 1 hour after 3H-TdR to 6.9 on the third day, indicating that the labeled cell population had divided. Labeled cells in the control and exposed cell populations were identified with electron microscopy. At 1 hour after injection of 3H-TdR, basal cells and nonciliated columnar cells were labeled. However, only nonciliated columnar cells were stimulated to divide by NO2. The labeled nonciliated columnar cell population was made up of serous, "intermediate" and goblet cells. Each of these cell types was stimulated to divide to the same degree. After cell division (1-7 days) labeled cells of all types were observed with labeled ciliated cells appearing on the third day. It was concluded that the basal cell is not a primary progenitor cell. The primary progenitor cell for epithelium in the upper airway is the total columnar secretory cell population (serous, "intermediate," and goblet cells).

Between January 1975 and December 1977 the Center for Disease Control treated 255 persons with the human diploid cell strain rabies vaccine who did not have development of an antibody titer to duck embryo vaccine (DEV) or who were at risk for having a serious reaction to DEV. Two hundred eighteen persons were treated postexposure, and 37 persons were treated preexposure. The antibody response to the vaccine was excellent, and the reaction rates were low. No person treated has had development of rabies. This study corroborates other studies that suggest that the human diploid cell strain rabies vaccines are safe and induce excellent antibody titers to rabies.

We reviewed national mortality data for 1973 through 1983 to assess the importance of diarrheal diseases as a cause of preventable childhood death in the United States. An average of 500 children aged 1 month to 4 years died each year with diarrhea reported as the cause of death. These diarrheal deaths were most common among children who were younger than 1 year of age, black, and living in the South, and were most common during the winter. In Mississippi, review of fatal cases of diarrhea identified maternal factors--black race, young age, unmarried status, low level of education, and little prenatal care--to be most associated with diarrheal death in the child. Fifty percent of these deaths occurred after a child had reached a medical facility. Our findings suggest that diarrheal deaths may be preventable and that targeted interventions could contribute to improved child survival in the United States.

An all-monoclonal antibody, time-resolved fluoroimmunoassay was compared with several enzyme immunoassays for the detection of respiratory syncytial virus and parainfluenza virus type 1, 2, and 3 antigens in clinical specimens. The most sensitive enzyme immunoassay for parainfluenza virus type 1 was an all-monoclonal antibody assay with biotin-labeled detector antibody and streptavidin-peroxidase conjugate, but for respiratory syncytial virus and parainfluenza virus types 2 and 3 the most sensitive assay was a polyclonal antibody assay with horse capture antibodies and bovine or rabbit detector antibodies with anti-species peroxidase. All tests were evaluated with nasopharyngeal aspirate specimens from respiratory illnesses and with cell culture harvests of multiple strains of each virus isolated over many years. The time-resolved fluoroimmunoassay detected respiratory syncytial virus antigen in 92% of the specimens positive by culture, which was a decidedly higher sensitivity than either the monoclonal or polyclonal antibody enzyme immunoassay format (62 and 76%, respectively). For the parainfluenza viruses the time-resolved fluoroimmunoassay detected type-specific antigen in 94 to 100% of culture-positive specimens and again was more sensitive than the all-monoclonal antibody enzyme immunoassays (75 to 89%) or all-polyclonal antibody enzyme immunoassays (66 to 95%). Combined with results from a previously reported adenovirus time-resolved fluoroimmunoassay, these tests identified respiratory antigens in large numbers of clinical specimens.

Virus infectivity and antibody neutralization titers for respiratory syncytial virus were determined in cell cultures in microtiter plates. After an appropriate incubation period, the cells were fixed, and an enzyme-linked immunosorbent assay was performed directly in the microtiter plates for detection of virus. Results could be read and recorded automatically, which is especially helpful when running large numbers of tests.

In 1984, simultaneous outbreaks of aplastic crisis and erythema infectiosum occurred in northeastern Ohio. Sera were analyzed from 26 patients with aplastic crisis: 24 had IgM specific for parvovirus B19, five had B19-like particles by electron microscopy, and 13 had DNA from B19; no sera from 33 controls had evidence of recent infection with B19 (P less than .0001). DNA from B19 was also detected in specimens of throat gargle and urine from two patients with aplastic crisis. Sera from 36 of 51 children with erythema infectiosum had B19-specific IgM, compared with serum from one of 42 susceptible controls (P less than .0001). DNA from B19 was detected in sera from only two of 51 patients who had erythema infectiosum. The secondary attack rates among susceptible contacts decreased with age (overall total, 49.6%). Differential rates of asymptomatic infection were observed among black (68.8%) and white (20.0%) household members (P = .003). These were the first identified simultaneous outbreaks of aplastic crisis and erythema infectiosum. Their occurrence provided an opportunity to study the epidemiology and spectrum of B19 infection with geographically and temporally matched comparison groups; our results support the hypothesis that infection with parvovirus causes these two clinical entities.

We describe the serum immunoglobulin A (IgA) antibody response to Norwalk virus infection in human volunteers and compare it with previously described IgM and total antibody responses. Whereas specific IgA and IgM peak within 2 weeks after onset of symptoms, titers of total blocking antibody continue to rise, implying mediation by IgG antibody.

A capture enzyme immunoassay specific for Norwalk IgM class antibody was developed. The assay was moderately sensitive, identifying 33/53 (62%) of patients with naturally acquired Norwalk virus infection and 17/18 (94%) of experimentally infected volunteers. The assay was also specific for IgM class antibody and acute Norwalk virus infection and results were generally reproducible. A specific IgM response correlated with seroconversion by total antibody blocking assay and occurred independently of clinical symptoms. Among 81 symptomatic cases composing seven Norwalk outbreaks, specific IgM was absent from acute phase sera collected less than or equal to three days post onset, and was uncommon in sera collected within one week and after five weeks, with an optimal collection time at about two to three weeks. The Norwalk IgM capture immunoassay may be used to augment paired sera assays in the identification of Norwalk-associated outbreaks of acute gastroenteritis.