Spirochetosis in California game chickens

An outbreak of spirochetosis occurred in a flock of 75 game chickens in California during fall 1991. Affected birds were weak and anemic. Many had greenish diarrhea. Spirochetes were seen on Giemsa-stained blood smears and in silver-stained tissue sections of kidney, liver, and spleen. Splenomegaly, which is reported to be characteristic of fowl spirochetosis, was not observed in two acutely infected chickens.     

Leptospira interrogans antibodies in feral pigs from New South Wales

The sera of 195 hunter-killed feral pigs (Sus scrofa), collected in New South Wales (Australia) from April to November 1995, were screened against a reference panel of 14 Leptospira interrogans serovars using a microscopic agglutination test (MAT). The panel represented those serovars previously isolated from wild and domestic mammals in mainland Australia. Antileptospiral agglutinins were detected in 20% of the sera tested and included nine L. interrogans serovars. The majority of serological reactors (63%) were to L. interrogans serovar pomona. Sera from 26% of immunoreactors cross reacted with antigens from one or more serovars. No differences were noted in the prevalence of L. interrogans antibodies between the sexes, or between pigs from areas of low and high rainfall. The implications of leptospirosis in feral pigs on the transmission of leptospires to wildlife, livestock, and humans are discussed.     

Evaluation of bluetongue virus diagnostic tests in free-ranging bighorn sheep

Five bluetongue virus (BTV) diagnostic tests were evaluated for use in free-ranging bighorn sheep. We sampled one bighorn sheep population four times between 1989 and 1995. The tests evaluated included virus isolation (VI), polymerase-chain reaction (PCR), serum neutralization (SN), agar-gel immunodiffusion (AGID), and competitive enzyme-linked immunosorbent assay (c-ELISA). The c-ELISA, AGID and SN tests had high levels of agreement in determining serogroup exposure in bighorn sheep. We used maximum-likelihood algorithms to estimate the parameters of each diagnostic test used. Although the c-ELISA and AGID had high sensitivity and specificity, the SN had perfect specificity but lower apparent sensitivity. Due to the potential of cross-reactions among multiple serotypes, results of the SN must be interpreted with caution when assessing serotype exposure in an area where multiple serotypes are endemic. The PCR assay delineated convalescent antibody titers from more-recent infections, and consequently, was pivotal in distinguishing a different exposure pattern between the bighorn sheep and cattle in an adjacent herd. Based on an increasing seroprevalence (50% to 100%), BTV circulated through this bighorn sheep population between 1989 and 1993. This increase in seroprevalence coincided with a bighorn die-off due to BTV infection in June, 1991. An adjacent cattle herd was sampled in 1995 for comparison. The bighorn sheep and adjacent cattle had different patterns of exposure to BTV between 1994 and 1995. There was no evidence that BTV circulated through the bighorn sheep population from 1994 to 1995. In 1995, seroprevalence to BTV decreased to 72%, none of yearling bighorn was seropositive, and all of the 39 bighorn sheep were PCR-negative. In contrast, all adult cattle were seropositive to BTV by c-ELISA and SN, and 4 of the calves were seropositive; 11 of the 24 cattle were PCR-positive, including all five calves. Overall, the pattern of temporal herd immunity in the bighorn sheep appeared to follow a classic epidemic curve, with the appearance and subsequent disappearance of herd immunity coinciding with the 1991 die-off in this population. As low levels of herd immunity and high proportions of susceptible animals are key factors in the development of epidemics, this population of bighorn sheep may be at increased risk for a BTV epidemic in the future.     

The HLD (CalMod) index and the index question

Twenty free-ranging guanaco (Lama guanicoe) in Chubut Province, Argentina, were immobilized for health evaluations. All but two animals appeared to be in good condition. Hematology, serum chemistry, and vitamin and mineral levels were measured, and feces were evaluated for parasites. Serology tests included bluetongue, brucellosis, bovine respiratory syncitial virus, bovine viral diarrhea/mucosal disease, equine herpesvirus 1, infectious bovine rhinotracheitis, Johne's disease (Mycobacterium paratuberculosis), foot and mouth disease, leptospirosis (17 serovars), parainfluenza-3, and vesicular stomatitis. Blood samples from 20 domestic sheep (Ovis aries) maintained in the same reserve with the guanaco were also collected at the same time for serology tests. No guanaco had positive serologic tests. Sheep were found to have antibody titers to bovine respiratory syncytial virus, Johne's disease, leptospirosis, and parainfluenza-3. There was no apparent difference in external appearance or condition, or statistical difference in blood test values, between the animals that were positive or negative for parasite ova.     

Coccidioidomycosis in free-living California sea lions (Zalophus californianus) in central California

Coccidioidomycosis is described in seven California sea lions (Zalophus californianus) admitted to The Marine Mammal Center, Sausalito, California (USA), between January 1986 and December 1994. Diagnoses were confirmed by histology in all seven cases, culture in three cases, and serology in one case. These are believed to be the first published cases of coccidioidomycosis in free-ranging California sea lions.     

Validity of dietary recall over 20 years among California Seventh-day Adventists

Past dietary habits are etiologically important to incident disease. Yet the validity of such measurements from the previous 10-20 years is poorly understood. In this study, the authors correlated food frequency results that were obtained in 1994-1995 but pertained to recalled diet in 1974 with the weighted mean of five random 24-hour dietary recalls obtained by telephone in 1974. The subjects studied were 72 Seventh-day Adventists who lived within 30 miles of Loma Linda, California; had participated in a 1974 validation study; were still alive; and were willing to participate again in 1994. A method was developed to allow correction for random error in the reference data when these data had differentially weighted components. The results showed partially corrected correlation coefficients of greater than 0.30 for coffee, whole milk, eggs, chips, beef, fish, chicken, fruit, and legumes. Higher correlations on average were obtained when the food frequencies were scored simply 1-9, reflecting the nine frequency categories. The 95% confidence intervals for 15 of the 28 correlations excluded zero. Incorporation of portion size information was unhelpful. The authors concluded that in this population, data recalled from 20 years ago should be treated with caution but, for a number of important foods, that the degree of validity achieved approached that obtained when assessing current dietary habits.     

Darkfield microscopic (DFM) and serologic evidences for leptospiral infection in panuveitis cases

186 out of 226 (82%) panuveitis cases showed the presence of leptospira in their blood samples by dark field microscopy. 75% cases were found positive for leptospira after low speed centrifugation and an additional 7% became positive after high speed centrifugation. Leptospirosis was four times more common in males than in females. The disease was more prevalent in the age group of 15 to 54 years. MAT was performed in 23 cases of which 9 were positive. ELISA was performed in 20 cases of which 9 were positive. DFM was positive in 19 out of these 23 cases. MAT, ELISA and DFM were positive in six cases. Highest antibody titre was found due to L. autumalis alone in two cases, L. autumnalis, and L. pomona in one case, L. bharathy in one case, L. lanka alone in one case and L. pomona one in one case. DFM was found to be more sensitive in a smal number of cases and hence DFM needs further evaluation by other workers in this field.     

Hospital vascular surgery volume and procedure mortality rates in California, 1982-1994

PURPOSE: Little is known about the long-term growth and outcomes of vascular surgery procedures over time. Trends in the use of three major vascular surgery procedures by a general population-lower extremity arterial bypass (LEAB), carotid endarterectomy (CEA), and abdominal aortic aneurysm repair (AAA)-are described. The extent to which these procedures are being performed in low-, moderate-, and high-volume hospitals is examined. METHODS: California hospital discharge records for LEAB, CEA, AAA, lower extremity angioplasty, coronary angioplasty, and coronary bypass surgery (CABG) were studied in all non-federal hospitals between 1982 and 1994. The data were age- and sex-adjusted to describe procedure growth. In-hospital mortality rates for LEAB, CEA, and AAA are related to overall hospital procedure volume, using logistic regression to control for risk factors and time trends. RESULTS: Growth in the number of vascular procedures performed in California was modest between 1982 and 1994, with no age-adjusted growth. Lower extremity angioplasty grew considerably in the 1980s and has since plateaued. Annual in-hospital death rates declined for all procedures except ruptured AAA. Comparing the two 5-year periods of 1982-1986 and 1990-1994, in-hospital death rates decreased from 4.2% to 3.3% for LEAB, from 9.2% to 6.2% for unruptured AAA, and from 1.6% to 1.0% for CEA (p < 0.0001). The odds of dying for patients treated in high-volume hospitals for LEAB and CEA procedures compared with patients treated in hospitals performing fewer than 20 procedures in a year were 66.7% (p = < 0.0001) and 66.1% (p < 0.0001), respectively. For patients with ruptured and unruptured AAA procedures, the odds of dying in hospitals with at least 50 AAA procedures in a year were 49.1% (p < 0.0001) and 83.8% (p = 0.016), respectively, compared with the odds of dying in low-volume hospitals. CONCLUSIONS: In-hospital mortality rates for CEA, LEAB, and unruptured AAA have been significantly decreasing over time. Mortality is inversely related to hospital volume and directly related to patient age and emergency status. Mortality trends over time for ruptured AAA remains unchanged; however, mortality is less in high-volume hospitals. Coronary angioplasty (PTCA) has not had an impact on rates for LEAB.     

Seroepidemiology of emerging tickborne infectious diseases in a Northern California community

A seroprevalence and risk factor study of emerging tickborne infectious diseases (Lyme disease, ehrlichiosis, and babesiosis) was conducted among 230 residents of a semirural community in Sonoma County, California. Over 50% of residents reported finding a tick on themselves in the preceding 12 months. Samples from 51(23%) residents were seroreactive to antigens from one or more tickborne disease agents: 1.4% to Borrelia burgdorferi, 0.4% to Ehrlichia equi, 4.6% to Ehrlichia chaffeensis, and 17.8% to the Babesia-like piroplasm WA1. Only 14 (27%) of these seroreactive residents reported one or more symptoms compatible with these diseases. Seroreactivity was significantly associated with younger age (<16 years), longer residence in the community (11-20 years), and having had a physician's diagnosis of Lyme disease. In northern California, the risk of infection with these emerging tickborne diseases, particularly in children, may be greater than previously recognized.     

Naturally acquired leptospirosis in 36 dogs: serological and clinicopathological features

Case records of 36 dogs with confirmed leptospirosis diagnosed at the New York State College of Veterinary Medicine from 1980 to 1995 were reviewed retrospectively, and clinical, serological and pathological findings were recorded to characterise the epidemiology of this disease in upstate New York. Titres were directed predominantly against serovars grippotyphosa and/or pomona in 31 of 34 dogs. Convalescent titres were measured for 53 per cent of dogs. The most common clinical presentation was acute renal failure. Increased liver enzyme activity was documented in 22 of 36 dogs. It is clear from this study that Leptospira pomona and grippotyphosa are important pathogens capable of causing severe renal and hepatic injury in dogs.     

Immunization against leptospirosis: vaccine trials with heat-killed whole cell and outer envelope antigens in hamsters

Heat-killed whole cell and outer envelope antigens prepared from homologous virulent and avirulent strains of Leptospira serotypes canicola and pomona were evaluated for protecting hamsters against experimental leptospirosis. The heat-killed bacterins proved at least as effective as the outer envelope antigens, or more so, in providing protection against death and infection, and they are easier and more economical to prepare.     

Recent mortality patterns in California

Mortality among people with developmental disabilities was reviewed using recent data obtained from the California Department of Developmental Services. The time interval for this report was 1991-1995. We defined two study cohorts: one beginning in January 1991 and a second in April 1993. The latter period represented the years of implementation of the Coffelt settlement. Our primary interest was in the Coffelt period cohort. Statistically significant association with increased rates of mortality was found for community residence. A trend of declining mortality was noted for the community facilities from 1991-1995, but not for the developmental centers.     

Serosurvey of selected viral and bacterial diseases in wild swine from Oklahoma

Blood samples collected from 120 wild swine (Sus scrofa) in thirteen Oklahoma (USA) counties during 1996 were tested for antibodies against six viral and two bacterial diseases. No antibodies to swine brucellosis, pseudorabies, transmissible gastroenteritis, and vesicular stomatitis were detected. Antibody titers to one or more leptospiral serovars were found in 44% of the samples, the two most frequent serovars being Leptospira interrogans serovars bratislava (29%) and pomona (27%). Antibody against porcine parvovirus and swine influenza virus was detected in 17% and 11% of the swine, respectively. Two samples (2%) were positive for antibody to the recently emerged porcine reproductive and respiratory syndrome virus.     

Macroscopic agglutination test for rapid diagnosis of human leptospirosis

A commercially available slide agglutination test (SAT) for the diagnosis of human leptospirosis was evaluated by comparing it to an immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) and to the microscopic agglutination test (MAT). For all 108 patients, leptospirosis was diagnosed on the basis of a fourfold or greater increase in titer by MAT (seroconversion), and all but 1 of 245 controls were MAT negative (titers, <1:100). Both SAT and the IgM ELISA failed to detect one case of infection (sensitivity, 99%). Only 3 of 145 blood donors and none of the 100 patients with other illnesses were SAT positive (specificity, 99%). The overall results were similar for the three tests; however, SAT and ELISA were statistically more sensitive as initial screening tests. For 22% of the patients, the diagnosis of leptospirosis was made earlier by SAT than by MAT. SAT detected 27 (44%) of 62 MAT-negative patients with the first serum sample. ELISA and SAT had very similar results. Follow-up of patients for 1 year after the onset of symptoms showed a decreasing rate of positivity by SAT from the third month on. The rate of positivity by ELISA decreased more slowly, to about 67% by the end of the study. By MAT all patients were persistently reactive. SAT and ELISA seem to be convenient methods for the rapid and early screening for leptospirosis and could replace the less sensitive MAT. ELISA gives less subjective results than SAT and provides information on IgM kinetics, but it can be performed only by the more sophisticated laboratories. SAT is inexpensive, can be performed more quickly and more easily than ELISA, and could be used by the less well equipped laboratories.     

Antimicrobial resistance in Neisseria gonorrhoeae in the United States, 1988-1994: the emergence of decreased susceptibility to the fluoroquinolones

Antimicrobial susceptibilities of Neisseria gonorrhoeae have been prospectively determined in the Gonococcal Isolate Surveillance Project of the Centers for Disease Control and Prevention. From 1988 through 1994, susceptibilities were determined for 35,263 isolates from 27 clinics. Patients were demographically similar to those in nationally reported gonorrhea cases. In 1994, 30.5% of isolates had chromosomally or plasmid-mediated resistance to penicillin or tetracycline. Penicillin resistance increased from 1988 (8.4%) to 1991 (19.5%) and then decreased in 1994 (15.6%). Tetracycline resistance decreased from 1988 (23.4%) to 1989 (17.3%) and then increased in 1994 (21.7%). Most isolates (99.9%) were highly susceptible to broad-spectrum cephalosporins. Isolates with decreased susceptibility to ciprofloxacin increased from 1991 (0.4%) to 1994 (1.3%); 4 isolates were ciprofloxacin-resistant. Ciprofloxacin-resistant strains may not respond to therapy with recommended doses of fluoroquinolones, and the clinical importance of strains with decreased susceptibility is unknown. The emergence of fluoroquinolone resistance in N. gonorrhoeae in the United States threatens the future utility of this class of antimicrobials for gonorrhea therapy.     

Elective cervical discectomy in California: postoperative in-hospital complications and their risk factors

STUDY DESIGN: A retrospective cohort study of short-term outcomes after elective cervical discectomy in California hospitals. OBJECTIVES: To compare the frequency of elective cervical discectomy across population strata, to determine the frequency of adverse outcomes in the early postoperative period, and to identify risk factors for such outcomes. SUMMARY OF BACKGROUND DATA: Previous cervical discectomy series have been too small to analyze risk factors for early complications, and have originated from centers that may not adequately represent the population. METHODS: Computerized hospital discharge abstracts were obtained from the California Office of Statewide Health Planning and Development. Inclusion and exclusion criteria were applied to identify 10,416 routine discectomies at 257 hospitals in 1990-1991. Several categories of postoperative complications were identified, along with inpatient deaths, early reoperations, and nursing home transfers. Logistic regression was used to estimate the independent effects of patient characteristics on short-term outcomes. RESULTS: After adjustment for age and gender, blacks were 51% and Hispanics were 24% as likely as whites to undergo elective cervical discectomy. Overall, 6.7% of patients had one or more reported postoperative complications: 1.8% had noninfectious surgical complications, 1.8% had infectious complications, 4.0% had other medical complications, and 0.35% had unplanned reoperations before discharge. Fourteen inpatient deaths were reported (0.13%). Congestive heart failure, alcohol/drug abuse, chronic lung disease, previous spine surgery, psychological disorders, and chronic musculoskeletal disorders were independently associated with postoperative complications. Even after adjustment, risk was higher with advancing age, higher among women than among men, and higher after posterior fusion than after discectomy without fusion. CONCLUSIONS: The ethnic disparity in cervical discectomy rates suggests overuse among whites or underuse among minority populations. The complication rates reported here are similar to those synthesized from previous literature, except that the lower incidence of neurologic complications reflects our inability to distinguish preoperative from postoperative deficits. Important comorbidities should be identified and treated, if appropriate, before cervical spine surgery.     

Prevalence of Toxoplasma gondii antibodies in wild and domestic animals in northern California

Wild and domestic animals from 3 geographic-climatologic areas in northern California were tested for antibodies against Toxoplasma gondii. A total of 2,796 serum samples representing 37 species of wild mammals, 35 species of wild birds, and 5 species of domestic animals were tested by the indirect hemagglutination test. Of 1,174 wild mammal serums tested, 10.8% were positive, which compared with 14.7% of the 1,221 domestic mammal serums. Of 229 wild carnivores tested, 45% were seropositive, including 69% of 86 bobcats, 28% of 58 coyotes, 48% of 25 raccoons, 27% of 26 gray foxes, 22% of 32 striped skunks, a civet cat, and a mink. Serologic evidence of infection was found in 38% of 47 rural domestic cats, but none of the 7 dogs tested was seropositive. Of 160 murid rodents (rats and house mice) in rural habitats, 4% were seropositive, which compared with 2% of 399 cricetine rodents (mostly deer mice) collected from wilderness habitats. Seven percent of 56 wild Artiodactyla (deer and feral pigs) were seropositive, which compared with 15% of 1,048 domestic sheep tested. Of 401 birds tested, 3.5% had antibodies against T gondii. The highest prevalence of antibodies among birds was in crows (14%). Toxoplasma was isolated from 1 raven, by mouse inoculation. In general, the highest prevalence of seropositive carnivores, rodents, and sheep was in the coastal region below 100 ft elevation, where the weather is cool and damp for much of the year. In the central valley the highest prevalence among sheep was in areas under irrigation. The prevalence of antibodies was lowest in the mountain areas, where climatologic extremes prevail at various seasons of the year.     

A 1957 outbreak of Legionnaires' disease associated with a meat packing plant

Retrospective study shows that a 1957 outbreak of pneumonia in Austin, Minnesota, was Legionnaires' disease. Between June 7 and August 9, 1957, 78 persons were hospitalized with acute respiratory disease of unknown cause. Most had fever, headache, cough, and pneumonitis; two died. Ages ranged from 14-83 years; half of the patients were aged 55 years or older. Eighty-seven per cent were men. There were no secondary cases. Forty-six (59%) of the 78 patients were employees at a local meat packing plant, in distinction to the area's total working population (32%). Serosurvey of 15 of the 1957 outbreak cases and 30 controls matched for age, sex, and either occupation or residence was carried out in 1979. Antibody titers were determined for Legionella pneumophila serogroups 1-4 by means of indirect immunofluorescence. Twelve (80%) of the 15 cases and 13 (43%) of the 30 controls had antibody titers of 1:64 or greater to one or more of the L. pneumophila serogroups. Significant differences in L. pneumophila antibody titers (prevalence and level) were found between cases and control groups matched for residence (serogroups 1-3) or occupation (serogroups 2 and 3). Only three of 20 Austin residents with pneumonia diagnosed between 1978 and 1980 had L. pneumophila antibody titers of 1:128 or greater (p less than 0.001), in comparison to cases. These serologic data and the 1957 clinical and epidemiologic observations support the contention that this is the earliest documented outbreak of Legionnaires' disease.     

Endogenous adenosine attenuates long-term depression and depotentiation in the CA1 region of the rat hippocampus

We describe a series of 144 cases of leptospirosis diagnosed in 1989 in New Caledonia. The incidence rate was 90 per 100,000 person-years, with a specific mortality rate of 4% patients. Those affected (100 males, 44 females) were mainly aged 20 to 40 years. Incidence in rural areas (112 per 100,000 person-years) was seven times higher than in urban settlements. Two periods with higher incidence were noticed corresponding to highest rainfall. Twenty-nine of the cases occurred in individuals with professions commonly associated with leptospirosis. Contacts with rats, dogs and ditch or river water were the most frequently mentioned. The clinical expression of the disease was polymorphic: 60% of the patients had mild symptoms, 40% were acute forms including Weil's disease. Of 57 hospitalized, 23% were admitted with an initial diagnosis of dengue, and 37% with leptospirosis. Main clinical syndromes were: icterus and/or renal syndrome in 50% of patients, cardiac syndrome in 65%, acute myalgies in 58% and pulmonary syndrome in 50%. Although hemorrhages were uncommon (17%), 40% of the cases demonstrated thrombocytopenia (< 50,000/m3). Pancreatic involvement with hyperamylasemia was evidenced in 50% of cases. Twelve serogroups of Leptospira were implicated, Icterohaemorragiae predominated (41%), but was not associated with severe forms. In New Caledonia, like in all tropics, leptospirosis must be considered as an environmental diseases, professional activities being just an additional risk factor. Use of serology as a reliable tool for confirmation of cases in areas of high environmental contamination is discussed.