Fluctuating selection and global change: a synthesis and review on disentangling the roles of climate amplitude, predictability and novelty.

A formidable challenge for global change biologists is to predict how natural populations will respond to the emergence of conditions not observed at present, termed novel climates. Popular approaches to predict population vulnerability are based on the expected degree of novelty relative to the amplitude of historical climate fluctuations experienced by a population. Here, we argue that predictions focused on amplitude may be inaccurate because they ignore the predictability of environmental fluctuations in driving patterns of evolution and responses to climate change. To address this disconnect, we review major findings of evolutionary theory demonstrating the conditions under which phenotypic plasticity is likely to evolve in natural populations, and how plasticity decreases population vulnerability to novel environments. We outline key criteria that experimental studies should aim for to effectively test theoretical predictions, while controlling for the degree of climate novelty. We show that such targeted tests of evolutionary theory are rare, with marine systems being overall underrepresented in this venture despite exhibiting unique opportunities to test theory. We conclude that with more robust experimental designs that manipulate both the amplitude and predictability of fluctuations, while controlling for the degree of novelty, we may better predict population vulnerability to climate change.

DMSP-consuming bacteria associated with the calanoid copepod Acartia tonsa (Dana).

DMSP-consuming bacteria (DCB) were recovered from the body and fecal pellets of the copepod Acartia tonsa (Dana). The most probable number of DCB associated with starved A. tonsa was 9.2x10(2) cells copepod(-1). The abundance of DCB recovered from the copepod body increased to 1.6-2.8x10(4) after the copepod fed on DMSP-containing alga. DCB abundance associated with fecal pellets averaged 1.2x10(4) cells pellet(-1). In enrichment cultures, the DCB grew with a doubling time of 1.1-2.9 days, and consumed DMSP at a rate of 4.5-7.5 fmol cell(-1) day(-1). The apparent DMSP-to-DMS conversion efficiency was 25-41% for DCB from copepod body, and 99% for DCB from fecal pellets. Our study demonstrated that copepods and their fecal pellets may harbour dense populations of DCB, and that the copepod-bacteria coupling represents a novel mechanism for DMSP consumption in the water column.

Tuberculosis control in refugee settlements.

Tuberculosis and its management in refugees and other displaced persons in temporary settlements poses a challenge to organisations coordinating and providing care in refugee emergencies. This paper offers a consensus of the co-sponsoring agencies on practical recommendations for implementing measures aimed at both interrupting transmission of tuberculosis and treatment of individual patients.

Evaluation of the effectiveness of BCG vaccination using the case-control method in Buenos Aires, Argentina.

A retrospective case-control study was conducted in Argentina to determine the protection conferred by BCG vaccination against tuberculosis in children under six years of age, in an area where coverage is about 55%. A total of 175 tuberculosis patients were included. Five controls selected from patients treated at the same hospital as those under study for reasons other than tuberculosis were matched to each case on the basis of age, socioeconomic origin, nutritional status and place of residence. Information on BCG vaccination status was collected by an independent examiner. Tuberculosis localizations were as follows: 152 pulmonary, pleural and/or miliary; 18 meningitis; 2 lymphadenitis; 2 osteoarticular; and 1 otic. The diagnosis was based on bacteriological and histopathological tests, computerized tomography, radiology, clinical examination, endoscopy, and proved source of infection. The protective effect of BCG among those who were vaccinated was 73.0% with 95% confidence limits of 82% and 62%. According to these results BCG vaccination given early in life is very effective in preventing tuberculosis.

Eficacia de la vacunacion con BCG evaluada mediante el método de casos y testigos en Buenos Aires, Argentina / Effectiveness of BCG vaccination evaluated by means of the case control method in Buenos Aires, Argentina

A retrospective case control study was carried out between 1981 and 1984 in three hospitals in the western part of Greater Buenos Aires to determine protection provided by BCG tuberculosis vaccine in children under six years of age residing in a region of Argentina in which vaccination coverage is approximately 55 percent. A total of 175 cases of tuberculosis were included in the study. For each case five controls were selected (a total of 875) from among patients being treated in the same hospital for other causes unrelated to tuberculosis. The controls were selected on the basis of their similarity with the cases with respect to age, socioeconomic status, nutritional status, and place of residence. Information on the presence or absence of vaccination scarring and other data related to vaccination of both the cases and controls was collected by an independent examiner. In 152 of the 175 cases location of tuberculosis was pulmonary; in 15, miliary; and in six there were pleural complications. Of the remaining 23 cases, 18 were meningeal, two gangliar, two osteoarticular, and one otic. Diagnosis was based on bacteriological and histopathological analysis, computerized tomography, radiological and clinical examination, endoscopy, and verification of a focus of infection. The protective effect of BCG vaccine in vaccinated patients was 73 percent on average (CI95 percent = 62 to 85 percent

The protective effect of BCG vaccination of the newborn against childhood tuberculosis in an African community.

The latest controlled trial of BCG vaccination in southern India showed that two vaccines failed to confer protection against pulmonary tuberculosis. This result cast serious doubt on the effectiveness of BCG vaccination of the newborn, which is widely applied in developing countries. Therefore, WHO initiated a global research study to evaluate current programmes in developing countries. Part of this study was carried out in Lomé, Togo, in which child contacts of newly detected patients were followed up with clinical and radiological examinations. All observations were recorded according to a scoring system. Concomitant observations were made to verify the comparability of the vaccinated and unvaccinated children. Of the child contacts of 352 index cases, 1421 completed the examinations. The distribution of the final score made it possible to distinguish 175 children likely to suffer from tuberculosis: 113 among the 546 unvaccinated and 62 among the 875 vaccinated children. Significant incomparability was observed in respect of intensity of exposure: the vaccination coverage was relatively low, and the risk of disease relatively high, if a parent was the index case or the child shared the bedroom of the index case (which very often coincided). The other variables studied, including age and sex, turned out to be practically irrelevant as regards comparability. The estimate of the protective effect against all types of tuberculosis combined is 61.5%, which is slightly lower than suggested by the raw data (66%). The protective effect, however, appeared to increase considerably with severity of disease. In children of 5 years and older it was lower than in the younger children. Tuberculin testing failed to reveal any sensitivity induced by BCG in the vaccinated children. The distribution of the tuberculin reactions correlated poorly with the other diagnostic findings. Small reactions were only slightly more frequent in healthy than in sick children; only the very large reactions were associated with a higher risk of disease. This confirms that the tuberculin test is of very limited diagnostic value in young children.

The effectiveness of BCG vaccination of the newborn against childhood tuberculosis in Bangkok.

PIP: The Central Chest Clinic, Bangkok, Thailand, undertook a study among child contacts of newly discovered sputum-smear-positive patients with pulmonary tuberculosis to determine the effectiveness of BCG vaccination in young children. The study design resembled that of a controlled trial except that it was retrospective for vaccination, i.e., the vaccinated and control groups were not randomly selected. For this reason a number of measures were taken to allow for the comparability of groups to be verified and for adjustments to be made if necessary. The study was initiated in September 1981 and terminated in June 1984, after 971 index cases who reported contact with young children had been registered. Registration and initial examinations were completed for 1506 child contacts. The field teams could not trace 124 reported child contacts. In the case of 8 children, the initial examination was refused. Within a week of the detection of the index case, a visit was made to the household and personal data were collected. The contact children then were offered a clinical and X-ray examination at the Central Chest Clinic for the examinations. A clinical record was prepared for each child contact, the site of BCG vaccination was covered with a dressing (even if there had been no vaccination or scar), and the pediatrician administered a clinical examination and made a full-plate postero-anterior X-ray. The X-ray picture was examined by 2 readers. Suspect children were followed up for as long as there were medical indications. When indicated by the clinical or X-ray examination, a laryngeal swab was taken for culture and gland biopsies were made and examined by histopathology and culture. If tuberculosis was strongly suspected, treatment was initiated at once with rifampicin and isoniazid. For each child a final diagnosis was made at the end of the study. A scoring system proposed by WHO was used to obtain an indication of the probability of tuberculosis. As many as 1218 (81%) of the children had a BCG scar, and among those without a scar, 35 had a record of vaccination. Vaccination coverage as well as disease risk appeared to be associated with age. Stratification by age showed that this did not affect the calculated effectiveness of BCG vaccination. Apart from age, no differences between the vaccinated and the unvaccinated children were observed that call for stratification of the material. 284 tuberculosis suspects were found, 218 among the 1253 vaccinated and 66 among the 253 unvaccinated participants. The total incidence of tuberculosis was 14.5%; it was 12.6% among the vaccinated and 23.6% among the unvaccinated. Based on the data presented in Tables 1 and 8, and adjusting for the estimated 55 vaccinated children included among those without a scar or a vaccination record, the observed efficacy is 53% with 95% confidence limits of 64% and 38%; the observed number of cases among the vaccinated is 185 less than expected. Thus, although efficacy appears less, the effectiveness is far higher than with a more stringent diagnostic criteria.^ieng