Susceptibility of piglets to rabbit hemorrhagic disease virus following experimental infection.
(49/1248)
The possibility exists that rabbit hemorrhagic disease virus (RHDV) can be transmitted to swine, through lapinized hog cholera virus (HCV) vaccine. To investigate the infectivity of RHDV in swine, 16 four- to six-week-old piglets were inoculated subcutaneously with RHDV, and samples of liver, lung, spleen, kidney, bile, adrenal gland, tonsil, mesenteric lymph node, thymus, urine, buffy coat, and feces were collected from each of 2 animals on Days 0, 1, 2, 3, 5, 7, 14, and 28 post infection. Using reverse transcription-polymerase chain reaction, viral RNA was detected in most tissues by Day 3 and was absent after Day 5, except in lung and liver tissues, in which viral RNA was detected up to Day 14. Viral RNA was not detected in kidney, urine, feces or bile. Antibody responses, as detected by hemagglutination inhibition, were of low titer and short duration, and were similar in animals inoculated with viable RHD and in those given formalin-inactivated RHDV (n = 2). Neither viral RNA nor antibody were detected in the negative control or in the uninfected, in-contact animals. (+info)
Estimation of the basic reproduction number of measles during an outbreak in a partially vaccinated population.
(50/1248)
From March to July 1996 a measles outbreak occurred in northern Luxembourg with 110 reported cases centered around two primary schools (85 cases) and the surrounding community (25 cases). Eighty four suspected cases were confirmed serologically. Vaccine coverage was estimated from questionnaire-based surveys at the two primary schools to be 70 and 76%, respectively. Vaccine efficacy during the outbreak was estimated to be 94.6% [95% confidence interval (CI) 90.4-97.0]. Using the information from the, school surveys, we obtained estimates of the basic reproduction number of measles of 7.7 (95% CI 4.4-11.0) and 6.2 (95% CI 3.5-8.9), respectively. Assuming a 95% vaccine efficacy, these estimates correspond to minimal vaccine coverages of 91.6% (95% CI 81.4-95.7) and 88.3% (95% CI 75.5-93.4) which would have been necessary to minimize the chances of a major outbreak occurring. We can confirm that major outbreaks in similar school settings can only be prevented if vaccination coverage exceeds 90%. (+info)
Behavioural and serological human immunodeficiency virus risk factors among female commercial sex workers in Cambodia.
(51/1248)
BACKGROUND: The spread of human immunodeficiency virus (HIV) in Cambodia is mainly caused by sexual transmission and the high-risk group in this country are female commercial sex workers (CSW). There are two types of CSW, direct CSW (DCSW) and indirect CSW (IDCSW), who are different from each other in sexual activities. This study was conducted in order to describe the risk factors on HIV for each type of CSW, and to establish effective preventive strategies against the HIV epidemic among CSW. METHODS: The participants, 143 DCSW and 94 IDCSW, were interviewed using a questionnaire to determine their demographic characteristics and behaviour. Blood samples were taken for serological tests on HIV, Chlamydia trachomatis and syphilis. The association between their behavioural pattern and their serological results was analysed. RESULTS: The questionnaire study showed that IDCSW had a riskier behavioural pattern than DCSW. The HIV seroprevalence rates of the DCSW and the IDCSW were 52.4% and 22.3%, respectively. Univariate logistic analyses showed a significant association between HIV antibody (HIV-Ab) and current age, age at commencement of commercial sex work, duration of commercial sex work, and the seropositivity of Chlamydia trachomatis-IgG antibody (CT-IgG-Ab) among the DCSW. The analyses also showed a significant relationship between HIV-Ab and CT-IgG-Ab among the IDCSW. CONCLUSIONS: Improving condom use rate is very important in order to prevent an HIV epidemic among the two types of CSW. This study also suggests it is important to prevent sexually transmitted disease (STD) such as Chlamydia trachomatis infection. The STD control programme could be efficient for HIV prevention, especially among DCSW. (+info)
Morbidity of pertussis in adolescents and adults.
(52/1248)
The effect of age on the clinical presentation of pertussis was assessed in 664 adolescent and adult cases. Complications were more frequent in adults than in adolescents (28% vs. 16%). Pneumonia occurred in 2% of patients <30 years old but in 5%-9% of older patients. Urinary incontinence occurred in 34% of women >/=50 years old. Duration of cough, risk of sinusitis, and number of nights with disturbed sleep increased with smoking and asthma. The secondary attack rate in other household members >/=12 years was 11%. Pertussis in secondary case patients was less severe than in index case patients but presented with classic symptoms. The main source of infection in adolescents was schoolmates or friends; in adults it was workplace or their children. Teachers and health care workers had a greater risk of pertussis than did the general population. The burden of disease appears to increase with age, with smoking, and with asthma. (+info)
John Snow: the first hired gun?
(53/1248)
The 1854 English cholera outbreak led to reform of Victorian public health legislation, including the Nuisances Removal and Diseases Prevention Act. The reforms threatened the closure of many factories whose fumes were considered hazardous to the public's health. The second witness to appear before the Parliamentary committee considering the reforms was Dr. John Snow. Snow testified on behalf of the manufacturers threatened by the reforms. He stated that the fumes from such establishments were not hazardous. He contended that the workers in these factories did not become ill as a result of their exposures, and therefore these fumes could not be a hazard to the general public's health. Snow also presented data from the 1854 cholera outbreak as the basis for his belief that epidemic diseases were transmitted by water, not air. Although the data concerned cholera, Snow extended the inference to all epidemic diseases. When the committee's report was published, The Lancet chastised Snow in a stinging editorial. Parliament subsequently revised the bill in favor of the manufacturers and passed it into law. The implications of this particular episode in the history of epidemiology are discussed. (+info)
Brucellosis transmitted by bone marrow transplantation.
(55/1248)
We report a unique case of brucellosis transmitted by BMT. An 8-year-old boy with the diagnosis of Fanconi's anemia received an allogeneic BMT from his HLA-identical sibling. Routine culture from the infused marrow suspension grew Brucella abortus on day +4 post BMT. Spiking fevers occurred on days +2 and +16. The first febrile episode responded to broad-spectrum antibiotic therapy. However, the second episode did not. B. abortus was isolated from blood cultures taken during the second febrile episode. The Brucella agglutination titer was negative. Antibiotic therapy with oral doxycycline and i.v. gentamycin was successful with no recurrence of infection during 13 months of follow-up. The donor's blood culture was also positive for B. abortus and Brucella antibodies were detectable at 1:320 titer when he presented with fever and hepatosplenomegaly on day +32. We emphasize the need to consider brucellosis in patients undergoing BMT. We suggest that donor and recipient be evaluated for brucellosis especially in countries where the incidence of this infection is relatively high. (+info)
A model for evaluating intervention strategies to control salmonella in the poultry meat production chain.
(56/1248)
A model of the transmission of salmonella through the poultry meat production chain is developed, to predict the effects of intervention strategies for salmonella control. The model first describes the situation before intervention in terms of salmonella prevalences at flock level and some transmission parameters. After single control measures are translated into effects on these transmission parameters, the effects of sets of control measures (intervention strategies), can be calculated with the model. As research data are lacking, the model input parameters were derived from expert opinion. As an example, the effects of two intervention strategies proposed for the Dutch poultry industry are predicted. A sensitivity analysis is performed to indicate where the most effective control measures may be expected. Additionally, the reliability of the model predictions is studied by an uncertainty analysis. The use of the model as a tool for policy makers deciding about salmonella control strategies is discussed. (+info)