Epidemiology and infection in famine and disasters

Correlation of serum amyloid A1 and interleukin-1beta in response to anti-tubercular therapy

BACKGROUND

Host biomarkers are needed to monitor the response to anti-tubercular therapy (ATT) for ensuring effective therapy and preventing drug-resistant tuberculosis. We sought to find the correlation between the serum levels of SAA1 and IL-1beta in response to ATT in adult patients with pulmonary TB (PTB) or extra-pulmonary TB (EPTB).

METHODS

Blood samples of 32 patients with PTB and 28 patients with EPTB were analyzed. The blood samples were collected at baseline, two months and six months following treatment initiation. SAA1 and IL-1beta levels were measured by enzyme linked immunosorbent assay (ELISA).

RESULTS

In the PTB group, the mean levels of SAA1 decreased significantly (p <0.001) after the intensive phase (two months) and continuous phase (six months) of ATT in comparison with the baseline value. IL-1beta values also decreased significantly (p = 0.005) after the intensive phase (two months) compared with the baseline values. In the EPTB group, there was a significant reduction in the mean serum level of SAA1 (p <0.001) and IL-1beta (p = 0.001) after the intensive phase (two months) in comparison with the baseline value, whereas the reduction at six months was not significant.

CONCLUSIONS

SAA1 and IL-1beta may be useful potential treatment-monitoring biomarkers, especially in the intensive phase of therapy for both PTB and EPTB.

Environmental health conditions in the transitional stage of forcible displacement: A systematic scoping review

In 2019, 30,000 people were forced to leave their homes due to conflict, persecution, and natural disaster each day. Eighty-five percent of refugees live in developing countries, and they often face underfunded and inadequate environmental health services. Many displaced persons live in camps and other temporary settlements long after the displacement event occurs. However, there is little evidence on environmental health conditions in the transitional phase-defined by the United Nations High Commissioner for Refugees as six months to two years after displacement. To address this gap in research, we conducted a systematic scoping review of environmental health conditions, exposures, and outcomes in transitional displacement settings, as well as reported obstacles and recommendations for improvement. Eighty-eight publications met the inclusion criteria. Water supply was the most frequently discussed environmental health topic. Overcrowding was the most common risk factor reported, Vibrio cholerae was the most common pathogen reported, and diarrhea was the most commonly reported health outcome. Obstacles and recommendations were categorized as institutional, political or implementation-based. Identified knowledge gaps included minimal information on setting logistics and on topics such as menstrual hygiene, oral hygiene and fomite contamination. In order to improve environmental health conditions in transitional displacement settings, all levels of government and non-governmental organizations should increase collaboration to improve resource provision. This study is the first to report on environmental health conditions in this important time of transition between the emergency and protracted stages of displacement.

Environmental health in forced displacement: A systematic scoping review of the emergency phase

There are 70.8 million forcibly displaced people worldwide, including internally displaced persons, refugees, and asylum seekers. Since mortality rates are highest in the first six months of displacement, the provision of adequate services and infrastructure by relief organizations is critical in this "emergency phase." Environmental health provisions such as adequate water supply, excreta management, solid waste management, and vector control measures are among those essential services. We conducted a systematic scoping review of environmental health in the emergency phase of displacement (the six months following first displacement). A total of 122 publications, comprising 104 peer-reviewed and 18 grey literature publications, met the inclusion criteria. We extracted data relating to environmental health conditions and services, associated outcomes, and information concerning obstacles and recommendations for improving these conditions and services. Despite the fact that most displaced people live outside of camps, publications largely report findings for camps (n = 73, 60%). Water supply (n = 57, 47%) and excreta management (n = 47, 39%) dominate the literature. Energy access (n = 7, 6%), exposure to harsh weather from inadequate shelter (n = 5, 4%), food hygiene and safety (n = 4, 3%), indoor air quality (n = 3, 3%), menstrual hygiene management (n = 2, 2%), dental hygiene (n = 2, 2%), and ambient air quality (n = 1, 1%) are relatively understudied. The most common health outcome attributed to inadequate environmental conditions in the included publications is diarrhea (n = 43, 35%). We found that organizations and governments often embrace their own standards, however we call for policymakers to adopt standards no less rigorous than Sphere for the emergency phase of displacement. Although other reviews examine water, sanitation, and hygiene interventions in emergencies, this is the first systematic review of environmental health more broadly in the first six months of displacement.

Adipose Tissue Regulates Pulmonary Pathology during TB Infection

Tuberculosis (TB), caused by Mycobacterium tuberculosis infection, remains a major cause of mortality and morbidity worldwide. One-third of the world population is infected with M. tuberculosis, and about 15 million people with latent tuberculosis infection (LTBI) reside in the United States. An estimated 10% of individuals with LTBI are at risk of progressing to active disease. Loss of body mass, or wasting, accompanied by a significant reduction of body fat is often associated with active TB disease and is considered to be immunosuppressive and a major determinant of severity and outcome of disease. While the lungs are the primary site of M. tuberculosis infection and TB manifestation, recent reports have shown that adipose tissue serves as an important reservoir for M. tuberculosis In this article, we investigated the association between M. tuberculosis infection, adipose tissue, and TB disease progression using a transgenic inducible "fatless" model system, the FAT-ATTAC (fat apoptosis through targeted activation of caspase 8) mouse. By selectively ablating fat tissue during M. tuberculosis infection, we directly tested the role of fat cell loss and adipose tissue physiology in regulating pulmonary pathology, bacterial burden, and immune status. Our results confirm the presence of M. tuberculosis in fat tissue after aerosol infection of mice and show that loss of fat cells is associated with an increase in pulmonary M. tuberculosis burden and pathology. We conclude that acute loss of adipose tissue during LTBI may predispose the host to active TB disease.IMPORTANCE Although the lungs are the port of entry and the predominant site of TB disease manifestation, we and others have demonstrated that M. tuberculosis also persists in adipose tissue of aerosol-infected animals and directly or indirectly alters adipose tissue physiology, which in turn alters whole-body immuno-metabolic homeostasis. Our present report demonstrates a direct effect of loss of adipocytes (fat cells) on promoting the severity of pulmonary pathogenesis during TB, advancing our understanding of the pathogenic interactions between wasting and TB activation/reactivation.

Zinc oxide nanoparticles provide anti-cholera activity by disrupting the interaction of cholera toxin with the human GM1 receptor

Vibrio cholerae causes cholera and is the leading cause of diarrhea in developing countries, highlighting the need for the development of new treatment strategies to combat this disease agent. While exploring the possibility of using zinc oxide (ZnO) nanoparticles (NPs) in cholera treatment, we previously found that ZnO NPs reduce fluid accumulation in mouse ileum induced by the cholera toxin (CT) protein. To uncover the mechanism of action of ZnO NPs on CT activity, here we used classical (O395) and El Tor (C6706) V. cholerae biotypes in growth and biochemical assays. We found that a ZnO NP concentration of 10 μg/ml did not affect the growth rates of these two strains, nor did we observe that ZnO NPs reduce the expression levels of CT mRNA and protein. It was observed that ZnO NPs form a complex with CT, appear to disrupt the CT secondary structure, and block its interaction with the GM1 ganglioside receptor in the outer leaflet of the plasma membrane in intestinal (HT-29) cells and thereby reduce CT uptake into the cells. In the range of 2.5-10 μg/ml, ZnO NPs exhibited no cytotoxicity on kidney (HEK293) and HT-29 cells. We conclude that ZnO NPs prevent the first step in the translocation of cholera toxin into intestinal epithelial cells without exerting measurable toxic effects on HEK293 and HT-29 cells.

Spatiotemporal detection of unusual human population behavior using mobile phone data

With the aim to contribute to humanitarian response to disasters and violent events, scientists have proposed the development of analytical tools that could identify emergency events in real-time, using mobile phone data. The assumption is that dramatic and discrete changes in behavior, measured with mobile phone data, will indicate extreme events. In this study, we propose an efficient system for spatiotemporal detection of behavioral anomalies from mobile phone data and compare sites with behavioral anomalies to an extensive database of emergency and non-emergency events in Rwanda. Our methodology successfully captures anomalous behavioral patterns associated with a broad range of events, from religious and official holidays to earthquakes, floods, violence against civilians and protests. Our results suggest that human behavioral responses to extreme events are complex and multi-dimensional, including extreme increases and decreases in both calling and movement behaviors. We also find significant temporal and spatial variance in responses to extreme events. Our behavioral anomaly detection system and extensive discussion of results are a significant contribution to the long-term project of creating an effective real-time event detection system with mobile phone data and we discuss the implications of our findings for future research to this end.

Impacts of Climate Change on Inequities in Child Health

This paper addresses an often overlooked aspect of climate change impacts on child health: the amplification of existing child health inequities by climate change. Although the effects of climate change on child health will likely be negative, the distribution of these impacts across populations will be uneven. The burden of climate change-related ill-health will fall heavily on the world's poorest and socially-disadvantaged children, who already have poor survival rates and low life expectancies due to issues including poverty, endemic disease, undernutrition, inadequate living conditions and socio-economic disadvantage. Climate change will exacerbate these existing inequities to disproportionately affect disadvantaged children. We discuss heat stress, extreme weather events, vector-borne diseases and undernutrition as exemplars of the complex interactions between climate change and inequities in child health.

Serum PCT and its Relation to Body Weight Gain in Pulmonary Tuberculosis

The present study was aimed at assessing alterations in serum PCT in terms of its relation to body weight gain in pulmonary tuberculosis (PTB) patients undergoing treatment. Among patients (25-75 years) diagnosed with pulmonary tuberculosis, those that were new smear positive, showed sputum conversion at the end of 2 months and were declared clinically cured at the end of 6 months, were included in the study (n = 40). Serum procalcitonin was determined by BRAHMS PCT-Q kit. Patients were divided into two study groups-Group 1 (n = 21; serum PCT > 2 ng/ml at diagnosis), Group 2 (n = 19; serum PCT > 10 ng/ml at diagnosis). Body weights of all patients were obtained at three different time points, PTB-0 (at diagnosis), PTB-2 (after 2 months of intensive treatment) and PTB-6 (after 6 months of treatment). In both groups, mean body weights at PTB-2 and PTB-6 were significantly higher than those at PTB-0 and at PTB-6 were significantly higher than those at PTB-2. However, percentage body weight gain following 2 months of intensive treatment was higher in group 1 (4.05 % gain, p < 0.01) than in group 2 (2.75 % body weight gain, p < 0.05). Thus, the percentage gain in group 1 was tending more towards the desirable minimum gain of 5 % during intensive phase. Increase in serum PCT levels in pulmonary tuberculosis is inversely associated with body weight gain during treatment. Thus, PCT could play a role in regulation of body weight gain in anorectic conditions like tuberculosis.

Metabolic pathways in T cell fate and function

T cell growth and function must be tightly regulated to provide protection against foreign pathogens, while avoiding autoimmunity and immunodeficiency. It is now apparent that T cell metabolism is highly dynamic and has a tremendous impact on the ability of T cells to grow, activate and differentiate. Specific metabolic pathways provide energy and biosynthetic precursors that must support specific cell functions, as effector, regulatory, memory, and alloreactive T cells have distinct metabolic needs in immunity and inflammation. Here, we review the signaling pathways that control metabolism and how the metabolic phenotypes of T cell subtypes integrate with T cell function. Ultimately, these metabolic differences may provide new opportunities to modulate the immune response and treat inflammatory and autoimmune diseases.

Infectious diseases following disasters

Infectious diseases following natural disasters tend to occur as a result of the prolonged secondary effects of the disaster, mostly when there is an interruption of public health measures resulting from destruction of the local infrastructure. This article will review the infectious risks that occur as a result of natural disasters, with a focus on the mechanism of disease spread, infectious diseases after specific disasters, and various evidence-based interventions.

Alterations in serum levels of trace elements in tuberculosis and HIV infections

OBJECTIVE

To evaluate serum concentrations of trace elements in tuberculosis (TB) patients with or with out human immunodeficiency virus (HIV) coinfection before and after anti-TB chemotherapy.

SUBJECTS

A total of 155 TB patients, 74 of which were coinfected with HIV, and 31 healthy controls from Gondar, Ethiopia.

METHODS

Serum levels of copper, zinc, selenium and iron were determined using an inductively coupled plasma mass spectrometer from all subjects at baseline and from 44 TB patients (22 with HIV coinfection) at the end of an intensive phase of anti-TB chemotherapy.

RESULTS

Compared with the control group, the concentrations of iron, zinc and selenium were significantly lower (P<0.05) while that of copper and copper/zinc ratio was significantly higher (P<0.05) in the serum of TB patients. TB patients with HIV coinfection had significantly lower serum zinc and selenium concentrations and significantly higher copper/zinc ratio compared to that in TB patients without HIV coinfection (P<0.05). The serum concentration of zinc had significantly increased at the end of intensive phase of anti-TB chemotherapy in patients without HIV coinfection (P<0.05). An increase in serum selenium level was observed in TB patients with or without HIV coinfection after therapy. On the contrary, serum copper concentration and copper/zinc ratio declined significantly after anti-TB chemotherapy irrespective of HIV serostatus (P<0.05).

CONCLUSIONS

The results indicate that TB patients have altered profile of trace elements in their sera. This warrants the need for further investigations so that strategies for trace elements supplementation can be planned in addition to their potential as diagnostic parameters in monitoring responses to anti-TB chemotherapy.

Pulmonary Mycobacterium tuberculosis infection in leptin-deficient ob/ob mice

The development of active tuberculosis after infection with Mycobacterium tuberculosis is almost invariably caused by a persistent or transient state of relative immunodeficiency. Leptin, the product of the obese (ob) gene, is a pleiotropic protein produced mainly by adipocytes and is down-regulated during malnutrition and starvation, conditions closely connected with active tuberculosis. To investigate the role of leptin in tuberculosis, we intranasally infected wild-type (Wt) and leptin-deficient ob/ob mice with live virulent M. tuberculosis. Ob/ob mice displayed higher mycobacterial loads in the lungs after 5 and 10 weeks of infection, although the difference with Wt mice remained 1 log of M. tuberculosis colony forming unit. Nevertheless, ob/ob mice were less able to form well-shaped granuloma and lung lymphocyte numbers were reduced compared with Wt mice early during infection. In addition, ob/ob mice had a reduced capacity to produce the protective cytokine IFNgamma at the site of the infection early during infection and upon antigen-specific recall stimulation, and showed reduced delayed-type hypersensitivity reaction to intra-dermal tuberculin purified protein derivative. Leptin replacement restored the reduced IFNgamma response observed in ob/ob mice. Mortality did not differ between ob/ob and Wt mice. These data suggest that leptin plays a role in the early immune response to pulmonary tuberculosis.

Decreased plasma leptin concentrations in tuberculosis patients are associated with wasting and inflammation

Tuberculosis patients often suffer from severe weight loss, which is considered to be immunosuppressive and a major determinant of severity and outcome of disease. Because leptin is involved in weight regulation and cellular immunity, its possible role in tuberculosis-associated wasting was investigated. In an urban clinic in Indonesia, plasma leptin concentrations, indicators of adipocyte mass, appetite, C-reactive protein (CRP), tuberculin reactivity, and cytokine response were measured in tuberculosis patients and healthy controls. Plasma leptin concentrations were lower in patients than in controls (615 vs. 2,550 ng/liter; P < 0.001). Multivariate regression analysis showed that body fat mass and inflammation were two independent factors determining plasma leptin concentrations; there was a positive correlation between fat and leptin, whereas, unexpectedly, leptin was inversely associated with CRP and tumor necrosis factor-alpha production. Concentrations of both CRP and leptin were independently associated with loss of appetite. Our results do not support the concept that weight loss in tuberculosis is caused by enhanced production of leptin. Rather, loss of body fat leads to low plasma leptin concentrations, and prolonged inflammation may further suppress leptin production. Because leptin is important for cell-mediated immunity, low leptin production during active tuberculosis may contribute to increased disease severity, especially in cachectic patients.

Bioterrorism and the people: how to vaccinate a city against panic

Bioterrorism policy discussions and response planning efforts have tended to discount the capacity of the public to participate in the response to an act of bioterrorism, or they have assumed that local populations would impede an effective response. Fears of mass panic and social disorder underlie this bias. Although it is not known how the population will react to an unprecedented act of bioterrorism, experience with natural and technological disasters and disease outbreaks indicates a pattern of generally effective and adaptive collective action. Failure to involve the public as a key partner in the medical and public-health response could hamper effective management of an epidemic and increase the likelihood of social disruption. Ultimately, actions taken by nonprofessional individuals and groups could have the greatest influence on the outcome of a bioterrorism event. Five guidelines for integrating the public into bioterrorism response planning are proposed: (1) treat the public as a capable ally in the response to an epidemic, (2) enlist civic organizations in practical public health activities, (3) anticipate the need for home-based patient care and infection control, (4) invest in public outreach and communication strategies, and (5) ensure that planning reflects the values and priorities of affected populations.

War, famine and excess child mortality in Africa: the role of parental education

BACKGROUND

Civilian-targeted warfare and famine constitute two of the greatest public health challenges of our time. Both have devastated many countries in Africa. Social services, and in particular, health services, have been destroyed. Dictatorial and military governments have used the withholding of food as a political weapon to exacerbate human suffering. Under such circumstances, war and famine are expected to have catastrophic impacts on child survival. This study examines the role of parental education in reducing excess child mortality in Africa by considering Tigrai-Ethiopia, which was severely affected by famine and civil war during 1973--1991.

METHODS

This study uses data from the 1994 Housing and Population Census of Ethiopia and on communities' vulnerability to food crises. Child mortality levels and trends by various subgroups are estimated using indirect methods of mortality estimation techniques. A Poisson regression model is used to examine the relationship between number of children dead and parental education.

RESULTS

Although child mortality is excessively high (about 200 deaths per 1000 births), our results show enormous variations in child mortality by parental education. Child mortality is highest among children born to illiterate mothers and illiterate fathers. Our results also show that the role of parental education in reducing child mortality is great during famine periods. In the communities devastated by war, however, its impact was significant only when the father has above primary education. CONCLUSIONS Our findings suggest that both mother's and father's education are significantly and negatively associated with child mortality, although this effect diminishes over time if the crisis is severe and prolonged. The policy implications of our study include, obviously, reducing armed conflict, addressing food security in a timely manner, and expansion of educational opportunities.

Effect of perioperative nutrition, with and without arginine supplementation, on nutritional status, immune function, postoperative morbidity, and survival in severely malnourished head and neck cancer patients

BACKGROUND

Malnourished head and neck cancer patients are at increased risk of postoperative complications.

OBJECTIVE

We studied the effect of perioperative, arginine-supplemented nutritional support on nutritional status, immune status, postoperative outcome, and survival in severely malnourished (weight loss >10% of body weight) head and neck cancer patients undergoing major surgery.

DESIGN

Forty-nine patients were randomly assigned to receive 1) no preoperative and standard postoperative tube feeding, 2) standard preoperative and postoperative tube feeding, or 3) arginine-supplemented preoperative and postoperative tube feeding.

RESULTS

Patients in both prefed groups received approximately 9 d of preoperative tube feeding, resulting in energy intakes of 110% and 113% of calculated needs (compared with 79% in the control group; P = 0.007). Compared with no preoperative feeding, preoperative enteral nutrition did not significantly improve nutritional status or any of the studied biochemical or immunologic indexes. Major postoperative complications occurred in 53%, 47%, and 59% of patients in study groups 1, 2, and 3 (NS). A trend was seen toward better survival in the arginine-supplemented group (P = 0.15). Secondary analysis showed that survivors had better human leukocyte antigen-DR expression on monocytes (P = 0.05) and higher endotoxin-induced cytokine production (P = 0.010 for tumor necrosis factor alpha and P = 0.042 for interleukin 6) at the start of the study than did patients who died.

CONCLUSIONS

Nine days of preoperative tube feeding, with or without arginine, did not significantly improve nutritional status, reduce the surgery-induced immune suppression, or affect clinical outcome in severely malnourished head and neck cancer patients. Patients supplemented with arginine-enriched nutrition tended to live longer. Some markers of immune function may distinguish patients with good or bad prognoses.

Tumor necrosis factor (TNF)-alpha induces leptin production through the p55 TNF receptor

Tumor necrosis factor (TNF)-alpha acts directly on adipocytes to increase production of the lipostatic factor, leptin. However, which TNF receptor (TNFR) mediates this response is not known. To answer this question, leptin was measured in plasma of wild-type (WT), p55, and p75 TNFR knockout (KO) mice injected intraperitoneally with murine TNF-alpha and in supernatants from cultured WT, p55, and p75 TNFR KO adipocytes incubated with TNF-alpha. Leptin also was measured in supernatants from C3H/HeOuJ mouse adipocytes cultured with blocking antibodies to each TNFR and TNF-alpha as well as in supernatants from adipocytes incubated with either human or murine TNF-alpha, which activate either one or both TNFR, respectively. The results using all four strategies show that the induction of leptin production by TNF-alpha requires activation of the p55 TNFR and that although activation of the p75 TNFR alone cannot cause leptin production, its presence affects the capability of TNF-alpha to induce leptin production through the p55 TNFR. These results provide new information on the interplay between cells of the immune system and adipocytes.

Where health care has no access: the nomadic populations of sub-Saharan Africa

Nomadic and seminomadic pastoralists make optimal use of scarce water and pasture in the arid regions south of the Sahara desert, spreading from Mauretania in the west to Somalia in East Africa. We attempted to summarize the fragmentary evidence from the literature on the health status of these populations and to assess the best ways to provide them with modern health care. Infant mortality is higher among nomadic than among neighbouring settled populations, but childhood malnutrition is less frequent. Nomads often avoid exposure to infectious agents by moving away from epidemics such as measles. Trachoma is highly prevalent due to flies attracted by cattle. The high prevalence of tuberculosis is ascribed to the presence of cattle, crowded sleeping quarters and lack of health care; treatment compliance is generally poor. Guinea worm disease is common due to unsafe water sources. Helminth infections are relatively rare as people leave their waste behind when they move. Malaria is usually epidemic, leading to high mortality. Sexually transmitted diseases spread easily due to lack of treatment. Leishmaniasis and onchocerciasis are encountered; brucellosis occurs but most often goes undetected. Drought forces nomads to concentrate near water sources or even into relief camps, with often disastrous consequences for their health. Existing health care systems are in the hands of settled populations and rarely have access to nomads due to cultural, political and economic obstacles. A primary health care system based on nomadic community health workers is outlined and an example of a successful tuberculosis control project is described. Nomadic populations are open to modern health care on the condition that this is not an instrument to control them but something they can control themselves.

Leptin modulates the T-cell immune response and reverses starvation-induced immunosuppression

Nutritional deprivation suppresses immune function. The cloning of the obese gene and identification of its protein product leptin has provided fundamental insight into the hypothalamic regulation of body weight. Circulating levels of this adipocyte-derived hormone are proportional to fat mass but maybe lowered rapidly by fasting or increased by inflammatory mediators. The impaired T-cell immunity of mice now known to be defective in leptin (ob/ob) or its receptor (db/db), has never been explained. Impaired cell-mediated immunity and reduced levels of leptin are both features of low body weight in humans. Indeed, malnutrition predisposes to death from infectious diseases. We report here that leptin has a specific effect on T-lymphocyte responses, differentially regulating the proliferation of naive and memory T cells. Leptin increased Th1 and suppressed Th2 cytokine production. Administration of leptin to mice reversed the immunosuppressive effects of acute starvation. Our findings suggest a new role for leptin in linking nutritional status to cognate cellular immune function, and provide a molecular mechanism to account for the immune dysfunction observed in starvation.

The refugee crisis in Africa and implications for health and disease: a political ecology approach

Political violence in civil war and ethnic conflicts has generated millions of refugees across the African continent with unbelievable pictures of suffering and unnecessary death. Using a political ecology framework, this paper examines the geographies of exile and refugee movements and the associated implications for re-emerging and newly emerging infectious diseases in great detail. It examines how the political ecologic circumstances underlying the refugee crisis influences health services delivery and the problems of disease and health in refugee camps. It has four main themes, namely, an examination of the geography of the refugee crisis: the disruption of health services due to political ecologic forces that produce refugees; the breeding of disease in refugee camps due to the prevailing desperation and destitution; and the creation of an optimal environment for emergence and spread of disease due to the chaotic nature of war and violence that produces refugees. We argue in this paper that there is great potential of something more virulent than cholera and Ebola emerging and taking a big toll before being identified and controlled. We conclude by noting that once such a disease is out in the public rapid diffusion despite political boundaries is likely, a fact that has a direct bearing on global health. The extensive evidence presented in this paper of the overriding role of political factors in the refugee health problem calls for political reform and peace accords, engagement and empowerment of Pan-African organizations, foreign policy changes by Western governments and greater vigilance of non-governmental organizations (NGOs) in the allocation and distribution of relief aid.

Infectious disease emergencies in disasters

This article discusses the relationship between disasters and infections. Infections that are reviewed include those resulting from (1) a breakdown of the usual mechanisms of infection control, (2) the introduction or emergence of pathogens, and (3) the movement of populations into new areas. Components of infectious-disease surveillance and disaster teams are detailed.

Post-disaster malaria in Costa Rica

INTRODUCTION

In recent years, controversy has surrounded the issue of whether infectious disease should be considered a serious potential consequence of natural disasters. This article contributes to this debate with evidence of a significant outbreak of malaria in Costa Rica's Atlantic region after the 1991 earthquake and subsequent floods.

METHODS

This study is an epidemiologic investigation of the incidence of malaria for the periods of 22 months before the April 1991 Limón earthquake and for 13 months afterward. Data were obtained from the Costa Rican Ministry of Health's malaria control program.

RESULTS

Some of the cantons in the region experienced increases in the incidence of malaria as high as 1,600% and 4,700% above the average monthly rate for the preearthquake period (p < or = 0.01). Causal mechanisms are postulated as relating to changes in human behavior (increased exposure to mosquitoes while sleeping outside, and a temporary pause in malaria control activities), changes in the habitat that were beneficial to mosquito breeding (landslide deforestation, river damming, and rerouting), and the floods of August 1991.

CONCLUSIONS

It is recommended that there be enhanced awareness of the potential consequences of disaster-wrought environmental changes. Date of Event: 22 April 1991; Type: Earthquake, 7.4 Richter scale;

LOCATION

Costa Rica; Number of deaths and casualties: 54 deaths and 505 moderate to severe injuries.

Nutrition, disease and death in times of famine

In this article we review the relationship between malnutrition and mortality, and the interaction of morbidity, with the aim of clarifying the health risks of malnutrition in situations of famine and food insecurity. Apart from reviewing what is known about this relationship, we highlight areas where further research is needed. Among refugee and famine affected populations living in camps, there appears to be a close association between high rates of malnutrition and excess mortality. Results from community-based prospective studies of malnutrition and mortality among individuals conclude that as nutritional status declines the risk of death increases, although the discriminating power of different nutritional indices and the strength of the association varies considerably in different locations and at different times. These differences are attributed mainly to the different prevailing patterns of morbidity and growth failure, which are influenced by both environmental and social factors. In situations of famine and population displacement, the deterioration in the health environment increases exposure to infection and is likely to raise the threshold of nutritional status which corresponds to an increased risk of mortality. This has important implications for nutritional assessments and interventions.

Malnutrition and mortality during recent famines in Ethiopia: implications for food aid and rehabilitation

The 1972-73 and 1984-85 famines varied significantly among different populations within famine areas at the regional, community and household levels. Political and social factors were crucial in this pattern. Evidence from both pastoral and farming areas indicates that the development of community-based resources may be less disruptive socially and economically and result in less morbidity and mortality than dependence on relief shelters. Areas needing further study are identified.

Food as an instrument of war in contemporary african famines: a review of the evidence

Famine is conventionally portrayed as a natural disaster expressed in terms of food scarcity and culminating in starvation. This view has attracted criticism in recent years as the political, legal and social dimensions of famine have become more clearly understood. This paper draws upon these criticisms to understand the particular conditions of famine creation in conflict situations. Following an examination of six contemporary African famines, it is suggested that the use of food as a weapon of war by omission, commission and provision has contributed to the creation of famine in recent decades. Despite the optimism for peace engendered by the demise of the Cold War, the momentum for conflict would seem to be sustained by internal factors, including economic and environmental decline, political instability and ethnic rivalry. Within these conflicts, the strategic importance of food is likely to remain central. This study highlights the need to link concerns with food security and public health to those of development, human rights and international relations.