World association for the advancement of veterinary parasitology (WAAVP) guideline for testing the efficacy of ectoparasiticides for fish.

This guideline is intended to assist in the planning and execution of studies designed to assess the efficacy of ectoparasiticides for fish. It is the first ectoparasite-specific guideline to deal with studies set in the aquatic environment and therefore provides details for the maintenance of environmental standards for finfish. Information is included on a range of pre-clinical study designs as well as clinical studies in commercial/production sites, set within a regulatory framework. It provides information on the study animals, their welfare, husbandry and environmental requirements during the study. The most commonly pathogenic ectoparasites are presented with relevant points regarding life history, host challenge and numeric evaluation. Preparation and presentation of both topical and oral test treatments is provided, together with guidance on data collection and analysis. The guideline provides a quality standard or efficacy studies on finfish, which will assist researchers and regulatory authorities worldwide and contribute to the wider objective of harmonisation of procedures.

Using the emerging Collaborative Cross to probe the immune system.

The Collaborative Cross (CC) is an emerging panel of recombinant inbred (RI) mouse strains. Each strain is genetically distinct but all descended from the same eight inbred founders. In 66 strains from incipient lines of the CC (pre-CC), as well as the 8 CC founders and some of their F1 offspring, we examined subsets of lymphocytes and antigen-presenting cells. We found significant variation among the founders, with even greater diversity in the pre-CC. Genome-wide association using inferred haplotypes detected highly significant loci controlling B-to-T cell ratio, CD8 T-cell numbers, CD11c and CD23 expression. Comparison of overall strain effects in the CC founders with strain effects at QTL in the pre-CC revealed sharp contrasts in the genetic architecture of two traits with significant loci: variation in CD23 can be explained largely by additive genetics at one locus, whereas variation in B-to-T ratio has a more complex etiology. For CD23, we found a strong QTL whose confidence interval contained the CD23 structural gene Fcer2a. Our data on the pre-CC demonstrate the utility of the CC for studying immunophenotypes and the value of integrating founder, CC and F1 data. The extreme immunophenotypes observed could have pleiotropic effects in other CC experiments.

Relative weight at ages 10 and 16 years and risk of endometriosis: a case-control analysis.

BACKGROUND: Although previous epidemiological studies have shown that women with endometriosis are more likely to be thinner and underweight, it is currently not clear whether this is a true characteristic of women who develop endometriosis or a consequence of their disease and its symptoms. The aim of this study was to investigate the relationship between endometriosis and relative weight in childhood and adolescence, prior to diagnosis. METHODS: This case-control study included 268 Australian women with surgically confirmed moderate to severe endometriosis (cases) and 244 women without endometriosis (controls). Relative weight at ages 10 and 16 years, as recalled and classified ('underweight', 'average weight' and 'overweight') separately by the women themselves and their mothers, was analyzed. RESULTS: Women who reported being overweight at 10 years had an increased risk of endometriosis (OR 2.8; 95% CI 1.1-7.5). Mothers' reports and concordant responses among mother-daughter pairs were consistent with this association. There was no clear evidence of an association between relative weight at 16 years and risk of endometriosis. CONCLUSIONS: These data suggest that being overweight during late childhood is associated with the development of endometriosis; however, the results warrant confirmation in larger study populations.

Transmission of Mycobacterium tuberculosis from medical waste.

CONTEXT: Washington State has a relatively low incidence rate of tuberculosis (TB) infection. However, from May to September 1997, 3 cases of pulmonary TB were reported among medical waste treatment workers at 1 facility in Washington. There is no previous documentation of Mycobacterium tuberculosis transmission as a result of processing medical waste. OBJECTIVE: To identify the source(s) of these 3 TB infections. DESIGN, SETTING, AND PARTICIPANTS: Interviews of the 3 infected patient-workers and their contacts, review of patient-worker medical records and the state TB registry, and collection of all multidrug-resistant TB (MDR-TB) isolates identified after January 1, 1995, from the facility's catchment area; DNA fingerprinting of all isolates; polymerase chain reaction and automated DNA sequencing to determine genetic mutations associated with drug resistance; and occupational safety and environmental evaluations of the facility. MAIN OUTCOME MEASURES: Previous exposures of patient-workers to TB; verification of patient-worker tuberculin skin test histories; identification of other cases of TB in the community and at the facility; drug susceptibility of patient-worker isolates; and potential for worker exposure to live M tuberculosis cultures. RESULTS: All 3 patient-workers were younger than 55 years, were born in the United States, and reported no known exposures to TB. We did not identify other TB cases. The 3 patient-workers' isolates had different DNA fingerprints. One of 10 MDR-TB catchment-area isolates matched an MDR-TB patient-worker isolate by DNA fingerprint pattern. DNA sequencing demonstrated the same rare mutation in these isolates. There was no evidence of personal contact between these 2 individuals. The laboratory that initially processed the matching isolate sent contaminated waste to the treatment facility. The facility accepted contaminated medical waste where it was shredded, blown, compacted, and finally deactivated. Equipment failures, insufficient employee training, and respiratory protective equipment inadequacies were identified at the facility. CONCLUSION: Processing contaminated medical waste resulted in transmission of M tuberculosis to at least 1 medical waste treatment facility worker. JAMA. 2000;284:1683-1688.

Tobacco smoke as a risk factor for meningococcal disease.

BACKGROUND: Since 1992 the US Pacific Northwest has experienced a substantial increase in the incidence of serogroup B meningococcal disease. The current meningococcal polysaccharide vaccine is poorly immunogenic in young children and does not protect against N. meningitidis serogroup B. Defining alternative approaches to the prevention and control of meningococcal disease is of considerable public health importance. METHODS: We performed a case-control study comparing 129 patients in Oregon and southwest Washington with 274 age- and area-matched controls. We used conditional logistic regression analysis to determine which exposures remained associated with disease after adjusting for other risk factors and confounders and calculated the proportion of disease attributable to modifiable exposures. RESULTS: After adjustment for all other significant exposures identified, having a mother who smokes was the strongest independent risk factor for invasive meningococcal disease in children < 18 years of age [odds ratio (OR), 3.8; 95% confidence interval (CI) 1.6 to 8.9)], with 37% (CI 15 to 65) of all cases in this age group potentially attributable to maternal smoking. Adult patients were more likely than controls to have a chronic underlying illness (OR 10.8, CI 2.7 to 43.3), passive tobacco smoke exposure (OR 2.5, CI 0.9 to 6.9) and to smoke tobacco (OR 2.4, CI 0.9 to 6.6). Dose-response effects were seen for passive smoke exposure and risk of disease in all age groups. CONCLUSION: Tobacco smoke exposure independently increases the risk of developing meningococcal disease.

Risk of perinatal transmission of Chlamydia trachomatis by mode of delivery.

We compared the transmission rate of Chlamydia trachomatis infection from infected women to their infants after various modes of delivery. After vaginal birth, Chlamydia trachomatis was isolated from 58 of 125 infants with a cephalic presentation, and serological evidence of chlamydial infection was found in another eight. C. trachomatis was isolated from the only infant with a frank breech presentation. After Caesarean birth, C. trachomatis was isolated from two of 10 infants born after rupture of the membranes and from one of six without prior rupture of the membranes. No serological evidence of infection was found in any of the culture-negative infants born by Caesarean section. By survival analysis, rates of transmission were significantly lower after Caesarean section with rupture of the membranes before delivery than after vaginal delivery. Infants born to infected women are at risk of C. trachomatis infection regardless of route of delivery.

Randomized trial of silver nitrate, erythromycin, and no eye prophylaxis for the prevention of conjunctivitis among newborns not at risk for gonococcal ophthalmitis. Eye Prophylaxis Study Group.

OBJECTIVE: To compare the efficacy of commonly used forms of eye prophylaxis for newborns with no prophylaxis in the prevention of nongonococcal conjunctivitis. DESIGN: Randomized doubly masked clinical trial. SETTING: University of Washington Hospital and affiliated clinics, Seattle, between 1985 and 1990. SUBJECTS: The medical records of 8499 women were evaluated for possible participation; 2577 were eligible. Of the 758 enrolled, the infants of 630 were evaluable. INTERVENTION: Comparison of silver nitrate, erythromycin, and no eye prophylaxis given at birth for the prevention of conjunctivitis. MAIN OUTCOME MEASURES: Conjunctivitis during the first 60 days of life and nasolacrimal duct patency in the first 2 days of life. RESULTS: The frequency of impatent tear ducts at the 30- to 48-hour examination did not differ significantly by prophylaxis group. Among the 630 infants randomized and observed, 109 (17%) developed mild conjunctivitis. Sixty-nine (63%) of the cases appeared during the first 2 weeks of life. After 2 months of observation, infants allocated to silver nitrate eye prophylaxis at birth had a 39% lower rate of conjunctivitis (hazard ratio = 0.61, 95% confidence interval = 0.39 to 0.97), and those allocated to erythromycin had a 31% lower rate of conjunctivitis (hazard ratio = 0.69, 95% confidence interval = 0.44 to 1.07), than did those allocated to no prophylaxis. CONCLUSION: Silver nitrate eye prophylaxis caused no sustained deleterious effects and even provided some benefit to infants born to women without Neisseria gonorrhoeae. However, the effect was modest and against microorganisms of low virulence. The results suggest that parental choice of a prophylaxis agent including no prophylaxis is reasonable for women receiving prenatal care and who are screened for sexually transmitted diseases during pregnancy.

An interview study of participants in the Tacoma, Washington, syringe exchange.

Although European and Australian studies of syringe exchange programs have reported safer injection among participants and no increase in drug use, the generalizability of these findings to the US is uncertain. We report on the operations and potential effectiveness of the longest-operating syringe exchange in the US and compare our results to studies of exchange programs outside the US. The sample of 204 study subjects reported no change in the frequency of injection, from 155 to 152 injections per month, and a decline in the frequency of unsafe injections, from 56 to 30 times per month, while participating in the program. In all studies, participants report reduction in unsafe injections, and no increase in illicit drug use. However, the comparison also suggests that a high proportion of Tacoma exchangers have higher initial rates of drug injection, unsafe injection and homelessness, all of which were associated with unsafe injection while using the exchange. These indicate a need for additional services but that the Tacoma program is no less effective than European and Australian programs.

The bacterial etiology of conjunctivitis in early infancy. Eye Prophylaxis Study Group.

The authors conducted this study to determine the etiologic agents of conjunctivitis in early infancy. From 1985 to 1990, 630 infants enrolled in a randomized, controlled, double-masked study of eye prophylaxis were observed for 60 days after delivery for signs of conjunctivitis. The following isolates were categorized as pathogens: Haemophilus influenzae, Streptococcus pneumoniae, Neisseria cinerea, Klebsiella pneumoniae, and Chlamydia trachomatis. Using conditional logistic regression for analysis of 97 infant pairs, the authors identified isolates categorized as pathogens almost exclusively among cases (odds ratio (OR) = 18.0, 95% confidence interval (CI) 2.3-128). Among the microorganisms which have not usually been regarded as pathogens in the etiology of infant conjunctivitis, Streptococcus mitis was the only microorganism associated with an increased risk of conjunctivitis (OR = 5.3, 95% CI 1.8-15.0). The findings concerning the species of bacteria most often associated with conjunctivitis, as well as the finding that method of delivery is unimportant, suggest that bacteria were transmitted to the infants' eyes after birth and not from the birth canal.

Cefixime vs. cefaclor in the treatment of acute otitis media in children: a randomized, comparative study.

The efficacy of cefixime was compared with that of cefaclor in the treatment of 63 patients with acute otitis media. Patients received either a single dose of cefixime (8 mg/kg/day) or 3 divided doses of cefaclor (40 mg/kg/day). On the basis of otoscopic and tympanometric results at 10 to 14 days after the start of treatment, 28 (97%) of 29 cefixime-treated patients and 25 (78%) of 32 cefaclor-treated patients had resolution of acute otitis media. The clinical cure rate associated with all organisms was 94% for cefixime (16 of 17 isolates) and 68% (13 of 19 isolates) for cefaclor. The cure rate for Streptococcus pneumoniae was 12 of 12 (100%) for cefixime and 7 of 7 (100%) for cefaclor; the cure rate for Haemophilus influenzae (which includes 2 patients with mixed infections) was 3 of 4 (75%) for cefixime and 2 of 7 (29%) for cefaclor. One clinical relapse occurred among 29 cefixime-treated patients; however, at 28 days 9 recurrences were observed. Three of 25 (9%) cefaclor-treated patients failed and 4 (13%) relapsed at 10 to 14 days, an additional 2 (10%) experienced recurrence by Day 28. Eight (28%) cefixime-treated patients experienced adverse events (7 gastrointestinal and 1 diarrhea and rash); 8 (25%) cefaclor-treated patients experienced adverse events (all gastrointestinal). Our data suggest that both at end of therapy and for 14 days thereafter, cefixime given once a day for acute otitis media is clinically equivalent to cefaclor given 3 times a day.

Microscopic and ultrastructural studies of necrotizing hepatopancreatitis in Pacific white shrimp (Penaeus vannamei) cultured in Texas.

Granulomatous hepatopancreatitis of unknown etiology has been considered an important disease of Texas shrimp mariculture since 1985. Samples of Pacific white shrimp (Penaeus vannamei) were collected during 1986, 1987, and 1990 from three farms and an experimental mariculture facility with histories of production loss and increased mortality rates. Histologic and ultrastructural examination of shrimp from the four sites demonstrated two morphologically distinct, Gram-negative, double-enveloped, intracytoplasmic bacteria in necrotic hepatopancreatic epithelium. The more numerous small, pleomorphic rod as well as the helical organism are both taxonomically unclassifiable. The helical organism lacked ultrastructural characteristics of previously described helical or spiral bacteria. The relationship between the two organisms is unknown, but the pleomorphic rod is thought to play a major role in the disease. The role of a bacterial agent(s) in subsequent disease episodes is suggested by the observation that the use of oxytetracycline-medicated feed resulted in increased production and survival. Hepatopancreatic tubular epithelial necrosis and shrimp mortality correlated directly with the extent of infection by the small pleomorphic rod. Individual discrete bacteria were identified microscopically by Steiner and Steiner's method. Three major developmental stages of the disease were characterized based on the extent and number of hepatopancreatic tubular epithelial cells containing bacteria, the degree of tubular interstitial inflammation, and the extent and chronicity of tubular necrosis. Additional studies are needed to clarify the roles of the different bacteria identified and the potential role of environmental factors on the disease process.

Chronic Chlamydia trachomatis infections in infants.

OBJECTIVE: --To study the natural history of Chlamydia trachomatis infections in infants. DESIGN: --Bacteriologic and serologic study of an inception cohort. SETTING: --University of Washington Medical Center, Seattle. PARTICIPANTS: --Twenty-two infants with C trachomatis infections either not treated early in life or recurring after antimicrobial treatment. MAIN OUTCOME MEASURES: --Persistence of infection in various anatomic sites, antibody responses to specific serovars (serologic variants) of C trachomatis, and serovars of isolates from mothers and infants. RESULTS: --The cumulative proportion of infants still infected at the age of 1 year was 35%. Infection persisted in the conjunctiva, nasopharynx, and oropharynx in one child for as long as 866 days (28.5 months), when she was cured by treatment. In none of the infants did serologic tests suggest acquisition of infection other than at birth. Isolates of C trachomatis from mothers and their respective infants were always of the same serovar. CONCLUSIONS: --Many infants infected with C trachomatis at birth remain infected for months or years in the absence of specific antimicrobial therapy. Such infections may be confused with those acquired by sexual abuse.

The biomechanical effects of deep tissue support as related to brow and facelift procedures.

The adverse effects of increased tension across a healing wound are well known. However, the effect of closing a wound in layers in order to decrease tension on the epidermis has been a source of controversy. It is hypothesized that deep tissue support decreases skin tension upon wound closure. In order to clarify this issue, a two-part study was designed to address the immediate effects of deep tissue support in vitro using fresh-frozen cadavers and in vivo on patients undergoing scheduled surgery. Closing skin tension was measured at standard reference points in coronal brow lift and rhytidectomy procedures performed with and without galeal closure and superficial musculoaponeurotic system (SMAS) procedures, respectively. Deep tissue support was found to significantly (p less than 0.05) decrease skin tension at the time of skin closure at standard reference points in coronal brow lift and rhytidectomy procedures performed on fresh-frozen cadavers. Similar significant (p less than 0.05) decreases in closing skin tension also were found in vivo in patients undergoing similar surgical procedures. Stress relaxation was not found to play a significant role in contributing to this immediate decrease in closing skin tension. It would appear, therefore, that deep tissue support, in the form of galeal closure and an SMAS procedure in coronal brow lift and rhytidectomy procedures, respectively, provides increased viscoelastic support, producing immediate significant decreases in closing skin tension in these procedures. The beneficial effects on wound healing, scar formation, tension-related trophic skin changes, and possible improved long-term results are discussed.