Male mate preference and size-assortative mating in convict cichlids: A role for female aggression?

Many monogamous species demonstrate size-assortative mating patterns within natural populations. To better understand the role of intersexual selection in this process, we examined the effect of male preference for female body size in the convict cichlid (Amatitlania siquia). We provided males with a choice between females that differed in size, relative to each other and in relation to the focal male. Based on previous work, we expected males to prefer the largest available female mates across all treatments. Surprisingly, males spent more time near the smaller of two available females, but only when the other female was larger than the male. Additionally, males spent little time with either of two potential female mates when both females were larger than the male. We hypothesized that while males might prefer the largest of available females, female behavior might limit males from acting on this preference. To test this, males were force paired with a smaller or larger female. Pair formation only occurred when the female was smaller than the male, and females that were larger than their male counterparts showed significantly more aggression when compared to smaller females. Together, these data suggest that in the absence of intrasexual competition, male mate preference for large females in convict cichlids might be limited by female aggression.

A decade of change: tuberculosis in England and Wales 1988-98.

Tuberculosis cases in children (aged under 15 years) in the National Surveys rose from 308 (rate: 3.3 per 100,000) in 1988 to 408 (4.2 per 100,000) in 1993 and then fell to 364 (3.6 per 100,000) in 1998. The rates in white children were 1.6, 2.0, and 1.1 per 100,000 respectively; in Indian subcontinent children, the rates were unchanged between 1988 and 1993 at around 33 per 100,000 but fell to 23 per 100,000 in 1998. In black African children, the rates were 15, 34, and 71 per 100,000 respectively. From 1988 to 1998, the proportion of cases resident in London more than doubled to 49% (rate: 11.9 per 100,000) and the proportion of cases in children born abroad increased from 13% to 27% in the country as a whole. Although the overall rate of tuberculosis in children in England and Wales has changed little between 1988 and 1998, the distribution of disease has changed in line with the change in adults. Services for the diagnosis and treatment of tuberculosis in children should be adapted to the changing pattern of disease in this group. Continuous enhanced tuberculosis surveillance will enable more detailed and timely scrutiny of trends in tuberculosis in the future.

SARS: UK public health response--past, present and future.

The emergence of severe acute respiratory syndrome (SARS) in China, the occurrence of epidemics of SARS in China and a number of Southeast Asian countries, and its spread to countries elsewhere, have presented major challenges to public health systems throughout the world. Although very few true cases of SARS were detected in the United Kingdom, the public health response to the threat of SARS was considerable. The main components of this response were the early detection, isolation and reporting of cases, and the provision of comprehensive information to health professionals, cases, their contacts and the public. The development of the response to SARS raised a number of more general issues relevant to future infectious epidemic threats. Although the World Health Organisation has now declared SARS 'contained', the possibility of re-emergence is ever present. All countries will need to be vigilant and plan their response to the possibility of a renewed SARS epidemic.

Tuberculosis at the end of the 20th century in England and Wales: results of a national survey in 1998.

BACKGROUND: A national survey of tuberculosis was conducted in England and Wales in 1998 to obtain detailed information on the occurrence of the disease and recent trends. This survey also piloted the methodology for enhanced tuberculosis surveillance in England and Wales and investigated the prevalence of HIV infection in adults with tuberculosis. METHODS: Clinical and demographic data for all cases diagnosed during 1998 were obtained, together with microbiological data where available. Annual incidence rates in the population were estimated by age, sex, ethnic group, and geographical region using denominators from the 1998 Labour Force Survey. Incidence rates in different subgroups of the population were compared with the rates observed in previous surveys. The tuberculosis survey database for 1998 was matched against the Communicable Disease Surveillance Centre HIV/AIDS database to estimate the prevalence of HIV co-infection in adult patients with tuberculosis. RESULTS: A total of 5658 patients with tuberculosis were included in the survey in England and Wales (94% of all formally notified cases during the same period), giving an annual rate of 10.93 per 100 000 population (95% CI 10.87 to 10.99). This represented an increase of 11% in the number of cases since the survey in 1993 and 21% since 1988. In many regions case numbers have remained little changed since 1988, but in London an increase of 71% was observed. The number of children with tuberculosis has decreased by 10% since 1993. Annual rates of tuberculosis per 100 000 population have continued to decline among the white population (4.38) and those from the Indian subcontinent, although the rate for the latter has remained high at 121 per 100 000. Annual rates per 100 000 have increased in all other ethnic groups, especially among those of black African (210) and Chinese (77.3) origin. Over 50% of all patients were born outside the UK. Recent entrants to the UK had higher rates of the disease than those who had been in the country for more than 5 years or who had been born in the UK. An estimated 3.3% of all adults with tuberculosis were co-infected with HIV. CONCLUSIONS: The epidemiology of tuberculosis continues to change in England and Wales and the annual number of cases is rising. More than one third of cases now occur in young adults and rates are particularly high in those recently arrived from high prevalence areas of the world. The geographical distribution is uneven with urban centres having the highest rates. The increase in the number of cases in London is particularly large. Tuberculosis in patients co-infected with HIV makes a small but important contribution to the overall increase, particularly in London. To be most effective and to make the most efficient use of resources, tuberculosis prevention and control measures must be based on accurate and timely information on the occurrence of disease. A new system of continuous enhanced tuberculosis surveillance was introduced in 1999, based on the methodology developed in this national survey.

Leprosy in England and Wales.

This paper reviews cases of leprosy notified in England and Wales to the Central Leprosy Register since its inception in 1951. Leprosy remains a rare condition in England and Wales, with fewer than ten cases notified on average in recent years. No definite case of indigenously acquired leprosy has been reported since the disease became notifiable. Although only a small number of patients present each year, leprosy remains a debilitating disease, and the unfamiliarity of clinicians with this condition can lead to delays in diagnosis and undernotification.

Randomised placebo-controlled crossover trial on effect of inactivated influenza vaccine on pulmonary function in asthma.

BACKGROUND: Despite current recommendations, many people with asthma do not receive annual vaccination against influenza, partly because of concern that vaccine may trigger exacerbations. Colds can trigger exacerbations, which may be mistaken for vaccine-related adverse events. We undertook a double-blind placebo-controlled multicentre crossover study to assess the safety of influenza vaccine in patients with asthma, with allowance for the occurrence of colds. METHODS: We studied 262 patients, aged 18-75 years, who recorded daily peak expiratory flow (PEF), respiratory symptoms, medication, medical consultations, and hospital admissions for 2 weeks before the first injection and until 2 weeks after the second injection. Order of injection (vaccine and placebo) was assigned randomly. There was an interval of 2 weeks between injections. The main outcome measure was an exacerbation of asthma within 72 h of injection (defined as a fall in PEF of >20%). FINDINGS: Among 255 participants with paired data, 11 recorded a fall in PEF of more than 20% after vaccine compared with three after placebo (McNemar's test p=0.06); a fall of more than 30% was recorded by eight after vaccine compared with none after placebo (binomial test p=0.008). However, when participants with colds were excluded, there was no significant difference in the numbers with falls of more than 20% between vaccine and placebo (six vs three; binomial test p=0.51), although the difference for PEF decreases of more than 30% approached significance (five vs none; binomial test, p=0.06). This association was confined to first-time vaccinees. INTERPRETATION: Our findings indicate that pulmonary-function abnormalities may occur as a complication of influenza vaccination. However, the risk of pulmonary complications is very small and outweighed by the benefits of vaccination.

Influenza vaccination in 22 developed countries: an update to 1995.

This study expands and updates through 1995 our earlier report on influenza vaccine use in 18 developed countries. Five of the six countries with high levels of vaccine use in 1992 (> or = 130 doses/1000 population) showed little change or slight declines over the subsequent 3 years. The exception was the United States, where a new federal program for vaccination reimbursement for the elderly helped to increase vaccine distribution from 144 to 239 doses/1000 population. The six countries with medium levels of vaccine use in 1992 (76-96 doses/1000 population) increased to > or = 100 doses/1000 population by 1995. Among the six low-use countries in 1992 (< or = 65 doses/1000 population), only Finland showed substantial improvement (96 doses/1000 population) in 1995. Four new countries were added to the study. In Germany, vaccine use increased to 80 doses/1000 population in 1995, but in Ireland it remained at a low level (48 doses/1000 population). In Korea, vaccine use increased from 17 to 95 doses/ 1000 population during the period 1987-1995. In Japan, very high levels of vaccine use (approximately 280 doses/1000 population) in the early 1980s were associated with vaccination programs for school children. However, vaccine use fell precipitously when these programs were discontinued, and only 2 and 8 doses/1000 population were used in 1994 and 1995, respectively. In all 22 countries, higher levels of vaccine use were associated with vaccination reimbursement programs under national or social health insurance and were not correlated with different levels of economic development. Excluding Japan, in 1995 there was still a greater than fourfold difference between the highest and lowest levels of vaccine use among the other 21 countries in the study. Given its well established clinical effectiveness and cost-effectiveness, none of these countries has yet achieved the full benefits of its programs for influenza vaccination.

Choosing between competing health priorities. A government payer perspective.

Policy makers in developed countries are increasingly having to look at how they are to control the cost of healthcare in the face of the pressures of an aging population, the introduction (and cost) of new technologies and the increasing expectations of patients. To some extent, costs can be contained by concentrating on those technologies with proven clinical effectiveness. However, if priorities have to be set, some method of appraisal of the relative values of different interventions is required. Increasingly, economic analyses are being used to justify policies and the use of resources, by introducing measures of cost and quality as well as effectiveness. Those economic evaluations most commonly used, and their shortcomings, are described. Priority setting cannot, however, be reduced to a purely technical exercise. Decisions on what should and should not be funded from the public purse will be influenced by the overall framework of national aims and objectives and by professional opinion and public values; they will be more firmly based and defensible if they are subject to wide public discussion and debate.

Tuberculosis among the homeless at a temporary shelter in London: report of a chest x ray screening programme.

STUDY OBJECTIVE: To estimate the prevalence of active pulmonary tuberculosis in a homeless population in London and to assess whether those with suspected disease could be integrated into the existing health care system for further follow up and treatment. DESIGN: Voluntary screening programme based on a questionnaire survey and chest x ray. SETTING AND CASES: Screening programmes were set up over the Christmas period in 1992 and 1993 at a shelter for the homeless in London. An offer of screening was made to all individuals who visited the centre and an interviewer administered questionnaire was completed on those who volunteered for the screening. Chest x rays were carried out, developed, and read on site. Individuals with chest x rays features suggestive of tuberculosis or other medical problems were referred to a hospital of their choice. RESULTS AND OUTCOME: In 1992 nearly 1600 people visited the centre, of whom 372 volunteered for the screening and 342 were x rayed. Nineteen of the 342 (5.6%) had radiological features suggestive of active tuberculosis. In 1993 around 2000 homeless people visited the centre, of whom 270 volunteered for the screening and 253 were x rayed. Eleven (4.3%) had features consistent with active tuberculosis on the basis of the chest x rays and clinical examination by a chest physician. Overall, of 595 people x rayed in the two surveys, 30 (5%) had changes suggestive of active tuberculosis. Further investigations confirmed nine (1.5%) with active pulmonary disease and eight with no active tuberculosis. In 13, the diagnosis was not determined as four declined further investigation and nine did not attend their hospital appointment. CONCLUSION: Tuberculosis among the homeless remains a cause for concern. Follow up and treatment present unique difficulties. Services for the homeless need to include mechanisms for timely diagnosis and monitored treatment. Control programmes designed for the needs of the homeless are required.

Influenza vaccination in 18 developed countries, 1980-1992.

Influenza continues to be an important cause of preventable morbidity and mortality. Although influenza vaccine is widely recommended for older high-risk individuals, no studies have compared its use in different countries. We gathered information on influenza vaccine distribution in 18 developed countries for the period 1980-1992. During the 1980s there was a > or = 10-fold difference in annual per capita vaccine distribution among these countries, and in 1992 the difference was still more than 7-fold. Several countries demonstrated large increases in vaccine use over the study period, some showing substantial increases in specific years. Thirteen of the 18 countries recommend influenza vaccination for all elderly persons and 11 countries provide reimbursement for vaccination through national or social health insurance. These countries tend to have higher levels of vaccine use. Historical, economic and political factors also affect vaccination practices and policies, but their relationships to differences in vaccine use between countries are not known. A better understanding of why the use of influenza vaccine varies among countries will be important if its protective benefits are to be fully realized.