Extinction probabilities and times to extinction for populations of tsetse flies Glossina spp. (Diptera: Glossinidae) subjected to various control measures

A stochastic branching process was used to derive equations for the mean and variance of the probability of, and time to, extinction in tsetse populations. If the remnant population is a single inseminated female, the extinction probability increases linearly with adult mortality and is always certain if this mortality >3.5% per day even for zero pupal mortality. If the latter mortality is 4% per day, certain extinction is only avoided if adult mortality <1.5% per day. For remnant female populations >1, the extinction probability increases in a non-linear manner with adult mortality. Extinction is still certain for adult mortality >3.5% per day but, when the remnant population is >16, extinction is highly unlikely for adult mortality <2.5% per day if all females are inseminated. Extinction probability increases with increasing probability of sterile mating in much the same way as it does with increasing adult mortality. Extinction is assured if the probability of insemination can be reduced to 0.1. The required reduction decreases with increasing adult mortality. For adult mortality = 6-8% per day, the time to extinction increases only by one generation per order of magnitude increase in the starting population. Time to extinction is less sensitive to changes in the pupal than in the adult mortality. Reductions in the probability of insemination only become important when adult mortality is small; if the adult mortality is 8% per day, reducing the insemination probability from 1 to 0.1 only reduces the expected time to extinction by two generations. Conversely, increases in adult mortality produce important reductions in the required time even when the probability of insemination is 0.1. The practical, economic implication for the sterile insect technique is that the low-tech methods used to suppress tsetse populations should not be halted when the release of sterile males is initiated. The sterile insect technique should only be contemplated when it has been demonstrated that the low-tech methods have failed to effect eradication. The theory is shown to be in good accord with the observed results of tsetse control campaigns involving the use of odour-baited targets in Zimbabwe and the sterile insect technique on Unguja Island, Zanzibar.     

Causes and consequences of increase in child survival rates: ethnoepidemiology among the Hmong of Thailand.

The Hmong "hill tribe" minority in Thailand has much higher exposure to factors usually associated with risk of child mortality (high fertility, low status of women, low education, less use of modern medical care for births, exposure to warfare, economic and physical disruption, and poor hygienic conditions) than the rural ethnic Thai population. Nonetheless, infant mortality has declined from over 120 per 1000 to under 50 per 1000 live births among both these populations in the past 30 years. The reason for the rapid increase in child survival among the Hmong appears to be better access to and more use of modern curative and preventive medical care associated with road construction rather than major changes in social or hygienic conditions. Conventional wisdom suggests that high fertility is both a cause and a consequence of high infant and child mortality and that parents will not reduce fertility until they see that mortality has declined. Most Hmong parents recognize the decline in child mortality and attribute it to better access to modern medical care. Most Hmong parents also say that, if they were starting to have children now, they would want to have fewer children. Fear of child death is infrequently mentioned as a motive for having more children, and the perceived decline in child mortality is rarely mentioned as a reason for reduced fertility. Most Hmong parents explain their desired family size in terms of economic conditions rather than perceived risk of child mortality. Results of this study suggest that fertility and child mortality can vary independently of one another and that major reductions in child mortality can be accomplished without waiting for major social changes (e.g., improved education or status of women) or major reductions in fertility.     

Effects of larval density on a natural population of Culex restuans (Diptera: Culicidae): no evidence of compensatory mortality

1. This study investigated the effects of strong density dependence on larval growth, development, and survival of the mosquito Culex restuans (Theobald). It also tested the hypothesis that density reduction early in larval development could result in as many or more individuals surviving to adulthood (compensation or over‐compensation, respectively), or increased reproductive performance via rapid development and greater adult size. 2. In a field study of a natural population of C. restuans, the effects of a 75% lower density on percentage survivorship to adulthood, number of adults, development time, adult size, adult longevity, and size dependent fecundity were tested. 3. No evidence was found of compensation or over‐compensation in adult production, or of effects of lower density on percentage survivorship. Low density yielded significant increases in adult size, adult longevity, and size‐dependent fecundity, and a decrease in development time. 4. Estimated per‐capita population growth rate was significantly greater in the low‐density treatment than in the high‐density treatment. It is inferred that this difference was due to greater per‐capita resources, which increased female size and fecundity, and reduced development time. Greater per‐capita population growth could therefore result from early mortality of larvae, meaning that the hydra effect, which predicts greater equilibrium population with, as opposed to without, extrinsic mortality, may be possible for these mosquitoes.     

Demography and Life Histories of Sympatric Patas Monkeys, <Emphasis Type="Italic">Erythrocebus patas</Emphasis>, and Vervets, <Emphasis Type="Italic">Cercopithecus aethiops</Emphasis>, in Laikipia,Kenya

Mortality patterns are thought to be strong selective forces on life history traits, with high adult mortality and low immature mortality favoring early and rapid reproduction. Patas monkeys (Erythrocebus patas) have the highest potential rates of population increase for their body size of any haplorhine primate because they reproduce both earlier and more often. We report here 10 yr of comparative demographic data on a population of patas monkeys and a sympatric population of vervet monkeys (Cercopithecus aethiops), a closely related species differing in aspects of social system, ecology, and life history. The data reveal that 1) adult female patas monkeys have significantly higher mortality than adult female vervets; 2) infant mortality in patas monkeys is relatively low compared to the norm for mammals because it is not significantly different from that of adult female patas monkeys; and 3) infant mortality is significantly higher than adult female mortality in vervets. For both species, much of the mortality could be attributed to predation. An epidemic illness was also a major contributor to the mortality of adult female patas monkeys whereas chronic exposure to pathogens in a cold and damp microenvironment may have contributed to the mortality of infant vervets. Both populations experienced large fluctuations during the study period. Our results support the prediction from demographic models of life history evolution that high adult mortality relative to immature mortality selects for early maturation.     

Parental mortality rates in a western country after the death of a child: assessment of the role of the child's sex

Background: Loss of a child has been associated with elevated mortality rates in parents. Studies that focus on the influence of the child's sex on parental mortality are sparse.Objective: The main objective of the present study was to reevaluate the combined impact of the parents' and child's sex within a larger sample and focus on adverse health effects as an objective measure of possible long-term effects of maladaptive grief reactions.Methods: For the time period between 1980 and 1996, all children in Denmark who died before 18 years of age were identified. Parents who had lost a child were identified as the bereaved (exposed) group. Mortality rates of parents within the same-sex parent-child dyad were compared with mortality rates of parents within the opposite-sex parent-child dyad. Separate analyses were performed for bereaved fathers and for bereaved mothers, and additional analyses were conducted to examine the sole effect of the child's sex, irrespective of parental gender. A Cox proportional hazards regression model was used to estimate the hazard ratios (HRs) with 95% CIs.Results: The study population consisted of 21,062 parents (mean age at entry, 32 years; 11,221 mothers, 9841 fathers). Bereaved parents who had lost a child of the same sex had similar overall mortality as bereaved parents who had lost a child of the opposite sex (HR = 1.02; 95% CI, 0.85–1.22). Similar findings were observed for mortality due to natural death (HR = 0.96; 95% CI, 0.78–1.18) or mortality due to unnatural death (HR = 1.22; 95% CI, 0.84–1.77). Bereaved fathers who had lost a son had similar mortality as those bereaved by the death of a daughter (HR = 1.10; 95% CI, 0.86–1.40). Bereaved mothers who had lost a daughter had similar mortality as those bereaved by the death of a son (HR = 0.93; 95% CI, 0.70–1.22). Bereaved parents who had lost a son had mortality rates similar to those who had lost a daughter (HR = 1.09; 95% CI, 0.91–1.31). The interactions between grouping variable and sex of parents were not significant, indicating that the differential effect of losing a child based on sex of the child was not greater for fathers than for mothers.Conclusions: The results of this study revealed no significant effect of sex of the deceased child on mortality in these bereaved parents. The results might differ if this study was replicated in a population with a different grief culture and, more importantly, different gender schemas.     

Racial/Ethnic Differences in Early-Life Mortality in the United States

U.S. early-life (ages 1–24) deaths are tragic, far too common, and largely preventable. Yet demographers have focused scant attention on U.S. early-life mortality patterns, particularly as they vary across racial and ethnic groups. We employed the restricted-use 1999–2011 National Health Interview Survey–Linked Mortality Files and hazard models to examine racial/ethnic differences in early-life mortality. Our results reveal that these disparities are large, strongly related to differences in parental socioeconomic status, and expressed through different causes of death. Compared to non-Hispanic whites, non-Hispanic blacks experience 60 percent and Mexican Americans 32 percent higher risk of death over the follow-up period, with demographic controls. Our finding that Mexican Americans experience higher early-life mortality risk than non-Hispanic whites differs from much of the literature on adult mortality. We also show that these racial/ethnic differences attenuate with controls for family structure and especially with measures of socioeconomic status. For example, higher mortality risk among Mexican Americans than among non-Hispanic whites is no longer significant once we controlled for mother’s education or family income. Our results strongly suggest that eliminating socioeconomic gaps across groups is the key to enhanced survival for children and adolescents in racial/ethnic minority groups.     

Injury mortality in New Mexico's American Indians,Hispanics, and non-Hispanic whites, 1958 to 1982.

New Mexico has extraordinarily high injury mortality rates. To better characterize the injury problem in New Mexico, we calculated proportionate injury mortality and age-adjusted and age-specific injury mortality rates for the state''s 3 major ethnic groups--American Indians, Hispanics, and non-Hispanic whites. According to death certificate data collected from 1958 to 1982 and US population census figures, age-adjusted mortality rates for total external causes varied widely between the sexes and among the ethnic groups. Males in each ethnic group consistently had higher average annual age-adjusted external mortality rates than females. Injury mortality rates for American Indians of both sexes were 2 to 3 times higher than those for the other New Mexico ethnic groups. Motor vehicle crashes were the leading cause of death from injury for all 3 groups. Homicide accounted for twice the proportion of injury death in Hispanic compared with non-Hispanic white males (12.5% and 6.1%, respectively), while the proportion of males dying of suicide was highest in non-Hispanic whites. Deaths from excessive cold and exposure were leading causes of injury mortality for American Indians, but these causes were not among the leading causes of injury mortality for Hispanics or non-Hispanic whites. We conclude that the minority populations in New Mexico are at high risk for injury-related death and that the major causes of injury mortality vary substantially in the state''s predominant ethnic populations.     

Human Prion Diseases in the United States

Background

Prion diseases are a family of rare, progressive, neurodegenerative disorders that affect humans and animals. The most common form of human prion disease, Creutzfeldt-Jakob disease (CJD), occurs worldwide. Variant CJD (vCJD), a recently emerged human prion disease, is a zoonotic foodborne disorder that occurs almost exclusively in countries with outbreaks of bovine spongiform encephalopathy.This study describes the occurrence and epidemiology of CJD and vCJD in the United States.

Methodology/Principal Findings

Analysis of CJD and vCJD deaths using death certificates of US residents for 1979–2006, and those identified through other surveillance mechanisms during 1996–2008. Since CJD is invariably fatal and illness duration is usually less than one year, the CJD incidence is estimated as the death rate. During 1979 through 2006, an estimated 6,917 deaths with CJD as a cause of death were reported in the United States, an annual average of approximately 247 deaths (range 172–304 deaths). The average annual age-adjusted incidence for CJD was 0.97 per 1,000,000 persons. Most (61.8%) of the CJD deaths occurred among persons ≥65 years of age for an average annual incidence of 4.8 per 1,000,000 persons in this population. Most deaths were among whites (94.6%); the age-adjusted incidence for whites was 2.7 times higher than that for blacks (1.04 and 0.40, respectively). Three patients who died since 2004 were reported with vCJD; epidemiologic evidence indicated that their infection was acquired outside of the United States.

Conclusion/Significance

Surveillance continues to show an annual CJD incidence rate of about 1 case per 1,000,000 persons and marked differences in CJD rates by age and race in the United States. Ongoing surveillance remains important for monitoring the stability of the CJD incidence rates, and detecting occurrences of vCJD and possibly other novel prion diseases in the United States.     

Mortality in neurofibromatosis 1: an analysis using U.S. death certificates

Although neurofibromatosis 1 (NF1) is a relatively common autosomal dominant condition, information about its effect on mortality is limited. We used Multiple-Cause Mortality Files, compiled from U.S. death certificates by the National Center for Health Statistics, for 1983 through 1997. We identified 3,770 cases of presumed NF1 among 32,722,122 deaths in the United States, a frequency of 1/8,700, which is one-third to one-half the estimated prevalence. Mean and median ages at death for persons with NF1 were 54.4 and 59 years, respectively, compared with 70.1 and 74 years in the general population. Results of proportionate mortality ratio (PMR) analyses showed that persons with NF1 were 34 times more likely (PMR=34.3, 95% confidence interval [CI] 30.8-38.0) to have a malignant connective or other soft-tissue neoplasm listed on their death certificates than were persons without NF1. Overall, persons with NF1 were 1.2 times more likely than expected (PMR=1.21, 95% CI 1.14-1.28) to have a malignant neoplasm listed on their death certificates, but the PMR was 6.07 (95% CI 4.88-7.45) for persons who died at 10-19 years of age and was 4.93 (95% CI 4.14-5.82) for those who died at 20-29 years of age. Similarly, vascular disease was recorded more often than expected on death certificates of persons with NF1 who died at <30 years of age (PMR=3.26, 95% CI 1.31-6.71 at age <10 years; PMR=2.68, 95% CI 1.38-4.68 at age 10-19 years; and PMR=2.25, 95% CI 1.46-3.32 at 20-29 years) but not in older persons. This study supports previous findings of decreased life expectancy for persons with NF1 and, within the limitations of death certificates, provides population-based data about NF1 morbidity and mortality that are useful to clinicians caring for patients with NF1.     

Demographic diversity and sustainable fisheries

Fish species are diverse. For example, some exhibit early maturation while others delay maturation, some adopt semelparous reproductive strategies while others are iteroparous, and some are long-lived and others short-lived. The diversity is likely to have profound effects on fish population dynamics, which in turn has implications for fisheries management. In this study, a simple density-dependent stage-structured population model was used to investigate the effect of life history traits on sustainable yield, population resilience, and the coefficient of variation (CV) of the adult abundance. The study showed that semelparous fish can produce very high sustainable yields, near or above 50% of the carrying capacity, whereas long-lived iteroparous fish can produce very low sustainable yields, which are often much less than 10% of the carrying capacity. The difference is not because of different levels of sustainable fishing mortality rate, but because of difference in the sensitivity of the equilibrium abundance to fishing mortality. On the other hand, the resilience of fish stocks increases from delayed maturation to early maturation strategies but remains almost unchanged from semelparous to long-lived iteroparous. The CV of the adult abundance increases with increased fishing mortality, not because more individuals are recruited into the adult stage (as previous speculated), but because the mean abundance is more sensitive to fishing mortality than its standard deviation. The magnitudes of these effects vary depending on the life history strategies of the fish species involved. It is evident that any past high yield of long-lived iteroparous fish is a transient yield level, and future commercial fisheries should focus more on fish that are short-lived (including semelparous species) with high compensatory capacity.     

Kuru: An appraisal of five years of investigation

Abstract

Socioeconomic determinants of fertility and mortality were estimated by regression analysis for 29 low‐migration SMSA's located in the eastern part of the U. S. A low‐migration sample was chosen to maximize length of life history within the regions. Independent variables included per cent nonwhite, gross and net migration, population, density, medical care, welfare, per cent Catholic, education, income, and labor force participation. Density was measured by an index based on the census inventory of urban land. Mortality results include effects of migration on older nonwhite life expectancy, an inverse effect of density on life expectancy for older whites, specific income and educational effects on older life expectancies, different causative factors for e(50) and e(1,50), lack of influence of medical care (except for the nonwhite male), and significant infant mortality multiple correlations only for the nonwhite female. For nonwhite fertility, the inverse influences of per cent nonwhite and net migration 1960–70 were of greatest importance. White fertility showed a negative relationship with medical care and a positive one with nonwhite male e(0).     

Phenotypic plasticity and population differentiation in seeds and seedlings of the grass Anthoxanthum odoratum

Summary Seeds of Anthoxanthum odoratum were transplanted reciprocally between a xeric and a mesic field population that were genetically differentiated in adult traits. In one experiment seeds were reciprocally buried in bags in the soil, in a second experiment seeds were reciprocally sown in small plots. For most traits, site effects were much larger than seed-source effects. Germination, emergence, mortality of buried seed and recruitment were significantly higher at the xeric site than at the mesic site, irrespective of population of origin. Seed dormancy, was significantly higher for seed originating from the mesic than from the xeric population. Seedling recruits originating from the xeric population tended to be larger at both sites. Fecundity of seedling recruits depended on the environment; fecundities of plants growing in the xeric site had more than double the fecundity of plants growing in the mesic site. Phenotypic plasticity rather than population differences determined variation in performance in the seed and seedling stages.     

Socioeconomic status and infant mortality among Hispanics in a southwestern city

Recent investigations of infant mortality in the Southwest part of the US have shown that Spanish surname infant death rates are lower than might be expected from the relatively low socioeconomic standing of the Spanish surname population, a phenomenon that appears to be confined to the neonatal componont of the infant mortality rate. The relationship between socioeconomic status (ses) and infant mortality is examined overall and separately within the Anglo and Spanish surname populations of Corpus Christ, Texas. The investigation utilizes data from the 36 Nueces County census tracts. Most recent data on infant, neonatal, and postneonatal mortality was provided by the local health department. Subjects were limited to Anglos and those whites with at least 1 Spanish surname parent. The 1979-1983 cohort is analyzed. Information from the 1980 US census was utilized to divide the 36 census tracts into 3 SES groups: high, medium and low. The most immediately striking aspect of the findings is the significant inverse gradient in Anglos between SES and both the total infant mortality rate (IMR) and the neonatal mortality (NMR), a gradient which is nonexistent in the Spanish surname population as well as overall. In addition, Anglos and Spanish persons differ significantly with respect to all IMRs and NMRs. In the high and medium SES groups and overall, all Anglo rates are lower, while in the low SES group, Spanish surname rates are lower. These findings suggest that, among Anglos, SES is a crucial factor in infant deaths, whereas, among the Spanish surname population, having a medium or high SES does not offer any additional protection against mortality. Alternatively, lower SES does not translate into significantly lower infant mortality among Spanish persons. These findings provide support for the study's hypotheses that the SES-infant mortality association is weaker among Spanish persons than among Anglos. The analysis also shows the importance of analyzing the SES-infant mortality association separately by ethnicity. Studies in larger cities and also studies utilizing matched birth and death records are needed to further elaborate these findings.     

Influence of changing travel patterns on child death rates from injury: trend analysis.

OBJECTIVES: To examine trends in child mortality from unintentional injury between 1985 and 1992 and to find how changes in modes of travel contributed to these trends. DESIGN: Poisson regression modelling using data from death certificates, censuses, and national travel surveys. SETTING: England and Wales. SUBJECTS: Resident children aged 0-14. MAIN OUTCOME MEASURES: Deaths from unintentional injury and poisoning. RESULTS: Child deaths from injury declined by 34% (95% confidence interval 28% to 40%) per 100,000 population between 1985 and 1992. Substantial decreases in each of the leading causes of death from injury contributed to this overall decline. On average, children walked and cycled less distance and travelled substantially more miles by car in 1992 compared with 1985. Deaths from road traffic accidents declined for pedestrians by 24% per mile walked and for cyclists by 20% per mile cycled, substantially less than the declines per 100,000 population of 37% and 38% respectively. In contrast, deaths of occupants of motor vehicles declined by 42% per mile travelled by car compared with a 21% decline per 100,000 population. CONCLUSIONS: If trends in child mortality from injury continue the government''s target to reduce the rate by 33% by the year 2005 will be achieved. A substantial proportion of the decline in pedestrian traffic and pedal cycling deaths, however, seems to have been achieved at the expense of children''s walking and cycling activities. Changes in travel patterns may exact a considerable price in terms of future health problems.     

Racial differences in the relationship between infant mortality and socioeconomic status

This study presents an ecological analysis of the relationship between infant mortality and economic status by race in metropolitan Ohio, using census data on mother's residence and economic status determined by the percentage of low-income families living in each area. The analysis updates previous studies as white-non-white comparisons for total infant mortality are examined for the US censuses of 1960, 1970, 1980, 1990 and 2000; and more detailed period- and broad cause-specific rates are presented for 2000. A pronounced inverse association is consistently found between income status and infant mortality for whites, while for non-whites this pattern first emerges in 1979-81, disappears during the 1980s and then returns more strongly during the 1990s. Similarly, the 2000 data reveal a consistent inverse pattern between income status and infant mortality for white and non-white neonatal and postneonatal death rates, as well as exogenous cause-specific death rates. It is concluded that low-income whites and non-whites have infant mortality rates substantially higher than the overall rate for the population. Policy implications are discussed.     

Life-history parameters of a wild group of West African patas monkeys (Erythrocebus patas patas)

Based on long-term, although intermittent, observations (2 years 4 months of 14 years), we present data on birth seasonality, age at first birth, interbirth intervals, mortality rates, age at first emigration, and population change of a wild population of West African patas monkeys (Etythrocebus patas patas) in northern Cameroon. Birth season was from the end of December until the middle of February, corresponding to the mid-dry season. In spite of large body size, the patas females had the earliest age at first birth (36.5 monthsold) and the shortest interbirth intervals (12 months) compared to the closely related wild forest guenons. Age at first emigration of the males was considered to occur between 2.5 and 4.5 years. The group size of the focal group drastically decreased between 1984 and 1987, and steadily increased until 1994, then decreased again in 1997. The neighboring group also showed a similar trend in group size. The population decreases were likely to be caused by drought over 3 years. Annual crude adult mortality rate was 4% during population increase periods (PIP) between 1987 and 1994. It rose to 22% during all the periods (AP), including drought over 3 years. Despite their smaller body size, the rate of the wild forest guenons (Cercopithecus mitis) (4%) was the same and much lower than those of the patas during PIP and AP, respectively. The annual average juvenile mortality rate was 13% during PIP and it also rose to 37% during AP. That of wild forest guenons (C. ascanius) (10–12%) was a little lower and much lower than those of the patas during PIP and AP, respectively. These findings were consistent with Charnov's theoretical model of mammalian life-history evolution in that patas with high adult and juvenile mortality showed early and frequent reproduction in spite of large body size. Charnov also considered high adult mortality as a selective force and high juvenile mortality as a density-dependent consequence of high fecundity. Our results support the former but not the latter research findings.     

Paternal investment and status-related child outcomes: timing of father's death affects offspring success

Recent work in human behavioural ecology has suggested that analyses focusing on early childhood may underestimate the importance of paternal investment to child outcomes since such investment may not become crucial until adolescence or beyond. This may be especially important in societies with a heritable component to status, as later investment by fathers may be more strongly related to a child's adult status than early forms of parental investment that affect child survival and child health. In such circumstances, the death or absence of a father may have profoundly negative effects on the adult outcomes of his children that cannot be easily compensated for by the investment of mothers or other relatives. This proposition is tested using a multigenerational dataset from Bangalore, India, containing information on paternal mortality as well as several child outcomes dependent on parental investment during adolescence and young adulthood. The paper examines the effects of paternal death, and the timing of paternal death, on a child's education, adult income, age at marriage and the amount spent on his or her marriage, along with similar characteristics of spouses. Results indicate that a father's death has a negative impact on child outcomes, and that, in contrast to some findings in the literature on father absence, the effects of paternal death are strongest for children who lose their father in late childhood or adolescence.     

Life table studies on the paddy field population of the green rice leafhopper,Nephotettix cincticeps Uhler (Hemiptera: Cicadellidae), with special reference to the mechanism of population regulation

The population growth of the green rice leafhopper, Nephotettix cincticeps, in the paddy field was analyzed based on the life table data accumulated for six years. The paddy field population, which stems from the invading adults of the first generation (G-I), repeats two complete generations, and the hatchlings of the fourth generation (G-IV) enter diapause and overwinter as the fourth instar nymphs in fallow paddy fields. It was clarified that the density dependent reduction in the mean longevity and oviposition rate of adult females in G-II and III played a primary role in stabilizing the annual population densities. The annual average of the mean longevity of G-II females (3.9 days) was much shorter than that of G-III ones (7.7 days) and thus the density dependent reduction in the mean longevity induced a more prompt regulatory effect on the oviposition of G-II females compared with G-III ones. As the result, two equilibrium densities of eggs were obtained, e.g., ca 100 and 700 eggs per hill in G-III and IV, respectively. Density dependent decrease in the proportion of mature females in the adult population was especially conspicuous in G-II, and this was closely associated with the density dependent reduction in the mean longevity and fecundity. Thus, the density dependent dispersal (emigration) of the adult females by flight in G-II and III was the most convincing factor in the process of population regulation. The density dependent dispersal of the adult females is effective in avoiding the deleterious effects of nymphal crowding in a breeding habitat unit (a paddy field), and may result in a more even distribution of the population over a continuous habitat units in a locality than otherwise.     

Upper lethal temperature limits of the common furniture beetle Anobium punctatum (Coleoptera: Anobiidae)

The susceptibility of the egg, larval and adult stages of Anobium punctatum De Geer (Coleoptera: Anobiidae) to heat (46–54°C, 25–30% RH) was investigated. The larval stage was found to be most tolerant to heat. Very short exposure (5 min) of the larvae to temperatures of 52°C and above led to 100% mortality of the larvae. Treatment for 1.5 and 1 h at 47° and 48°C, respectively, led to 100% mortality. At 46°C, longer treatment time (2.5 h) was necessary. Exposure to 45°C for 3.5 h did not lead to immediate death of the larvae. The actual mortality is assumed to be greater than the results actually reported, as most of the larvae had not resumed normal activity at the end of the two-week observation period. The egg and adult stages were more sensitive to heat than the larvae; shorter exposure times were sufficient to obtain 100% mortality.     

Mortality associated with HIV-1 infection over five years in a rural Ugandan population: cohort study.

OBJECTIVE: To assess the impact of HIV-1 infection on mortality over five years in a rural Ugandan population. DESIGN: Longitudinal cohort study followed up annually by a house to house census and medical survey. SETTING: Rural population in south west Uganda. SUBJECTS: About 10,000 people from 15 villages who were enrolled in 1989-90 or later. MAIN OUTCOME MEASURES: Number of deaths from all causes, death rates, mortality fraction attributable to HIV-1 infection. RESULTS: Of 9777 people resident in the study area in 1989-90, 8833 (90%) had an unambiguous result on testing for HIV-1 antibody; throughout the period of follow up adult seroprevalence was about 8%. During 35,083 person years of follow up, 459 deaths occurred, 273 in seronegative subjects and 186 in seropositive subjects, corresponding to standardised death rates of 8.1 and 129.3 per 1000 person years. Standardised death rates for adults were 10.4 (95% confidence interval 9.0 to 11.8) and 114.0 (93.2 to 134.8) per 1000 person years respectively. The mortality fraction attributable to HIV-1 infection was 41% for adults and was in excess of 70% for men aged 25-44 and women aged 20-44 years. Median survival from time of enrollment was less than three years in subjects aged 55 years or more who were infected with HIV-1. Life expectancy from birth in the total population resident at any time was estimated to be 42.5 years (41.4 years in men; 43.5 years in women), which compares with 58.3 years (56.5 years in men; 60.5 years in women) in people known to be seronegative. CONCLUSIONS: These data confirm that in a rural African population HIV-1 infection is associated with high death rates and a substantial reduction in life expectancy.