Epidemiological and ecological characteristics of past dengue virus infection in Santa Clara, Peru.

To determine risk factors associated with dengue (DEN) virus infection among residents of Santa Clara, Peru, a rural Amazonian village near Iquitos, a cross-sectional serological, epidemiological and environmental survey was conducted. Demographic, social and behavioural information was obtained by standardized questionnaire from 1225 Santa Clara residents (61.3%) aged 5 years or older. Additional data were obtained on the environmental variables and immature mosquito species and abundance surrounding each household (n = 248). Sera that had been collected previously by the Peruvian Ministry of Health from residents were tested by an enzyme-linked immunosorbent assay (ELISA) for DEN virus IgG antibody. Antibody identity was verified as DEN by plaque reduction neutralization test. Data on individuals were analysed by univariate and multivariable methods, and independent sample t-tests. Spatial clustering was evaluated by comparing distances among DEN positive households. Overall, antibody prevalence was 29.4 % and more than doubled from the youngest to the oldest age groups, but did not differ by sex. Curiously, length of residence in Santa Clara was negatively associated with DEN virus antibodies. More frequent travel to Iquitos was positively associated with seroprevalence. Residents who obtained water from a river source rather than a local well also had significantly higher antibody prevalence. None of the environmental variables measured at each household corresponded to the patterns of antibody distribution. Of the larval mosquitoes found around residences, all were determined to be species other than Aedes. No evidence of spatial autocorrelation among antibody-positive households was detected. These results strongly suggested that recent DEN virus transmission did not occur in the village and that most infections of residents of this rural village were acquired while visiting the city of Iquitos.

Military assistance in complex emergencies: what have we learned since the Kurdish relief effort?

After the success of relief efforts to the displaced Kurdish population in northern Iraq following the Gulf War, many in the US military and the international relief community saw military forces as critical partners in the response to future complex emergencies (CEs). However, successes in subsequent military involvement in Somalia, Rwanda, the former Yugoslavia, and other CEs proved more elusive and raised many difficult issues. A review of these operations reinforces some basic lessons that must be heeded if the use of military forces in humanitarian relief is to be successful. Each CE is unique, thus, each military mission must be clearly defined and articulated. Armed forces struggle to provide both security and humanitarian relief, particularly when aggressive peace enforcement is required. Significant political and public support is necessary for military involvement and success. Military forces cannot execute humanitarian assistance missions on an ad hoc basis, but must continue to develop doctrine, policy and procedures in this area and adequately train, supply, and equip the units that will be involved in humanitarian relief. Militaries not only must cooperate and coordinate extensively with each other, but also with the governmental and non-governmental humanitarian relief organizations that will be engaged for the long term.

An outbreak of fulminant hepatitis delta in the Waorani, an indigenous people of the Amazon basin of Ecuador.

An outbreak of delta hepatitis occurred during 1998 among the Waorani of the Amazon basin of Ecuador. Among 58 people identified with jaundice, 79% lived in four of 22 Waorani communities. Serum hepatitis B surface antigen (HBsAg) was found in the sera of 54% of the jaundiced persons, and 14% of asymptomatic persons. Ninety-five percent of 105 asymptomatic Waorani had hepatitis B core (HBc) IgG antibody, versus 98% of 51 with jaundice. These data confirm that hepatitis B virus (HBV) infection is highly endemic among the Waorani. Sixteen of 23 (70%) HBsAg carriers identified at the onset of the epidemic had serologic markers for hepatitis D virus (HDV) infection. All 16 were jaundiced, where as only two of seven (29%) with negative HDV serology were jaundiced (P = .0006). The delta cases clustered in families, 69% were children and most involved superinfection of people chronically infected with HBV. The data suggest that HDV spread rapidly by a horizontal mode of transmission other than by the sexual route.

Chemical warfare agents: emergency medical and emergency public health issues.

The threat of exposure to chemical warfare agents has traditionally been considered a military issue. Several recent events have demonstrated that civilians may also be exposed to these agents. The intentional or unintentional release of a chemical warfare agent in a civilian community has the potential to create thousands of casualties, thereby overwhelming local health and medical resources. The resources of US communities to respond to chemical incidents have been designed primarily for industrial agents, but must be expanded and developed regarding incident management, agent detection, protection of emergency personnel, and clinical care. We present an overview of the risk that chemical warfare agents presently pose to civilian populations and a discussion of the emergency medical and emergency public health issues related to preparedness and response.

Medical preparedness for a terrorist incident involving chemical or biological agents during the 1996 Atlanta Olympic Games.

During the 1996 Centennial Olympic Games in Atlanta, Georgia, unprecedented preparations were undertaken to cope with the health consequences of a terrorist incident involving chemical or biological agents. Local, state, federal, and military resources joined to establish a specialized incident assessment team and science and technology center. Critical antimicrobials and antidotes were strategically stockpiled. First-responders received specialized training, and local acute care capabilities were supplemented. Surveillance systems were augmented and strengthened. However, this extensive undertaking revealed a number of critical issues that must be resolved if our nation is to successfully cope with an attack of this nature. Emergency preparedness in this complex arena must be based on carefully conceived priorities. Improved capabilities must be developed to rapidly recognize an incident and characterize the agents involved, as well as to provide emergency decontamination and medical care. Finally, capabilities must be developed to rapidly implement emergency public health interventions and adequately protect emergency responders.

Medical and public health services at the 1996 Atlanta Olympic Games: an overview.

Planning for the 2000 Sydney Olympic Games may benefit from the experience of the 1996 Atlanta Olympics. Excellent health promotion and prevention activities before and during the Games resulted in fewer medical and public health problems than anticipated. Despite this, there was room for improvement in the level of communication and cooperation between the many service providers to ensure the most appropriate and efficient responses.

Malaria among United States troops in Somalia.

PURPOSE: United States military personnel deployed to Somalia were at risk for malaria, including chloroquine-resistant Plasmodium falciparum malaria. This report details laboratory, clinical, preventive, and therapeutic aspects of malaria in this cohort. PATIENTS AND METHODS: The study took place in US military field hospitals in Somalia, with US troops deployed to Somalia between December 1992 and May 1993. Centralized clinical care and country-wide disease surveillance facilitated standardized laboratory diagnosis, clinical records, epidemiologic studies, and assessment of chemoprophylactic efficacy. RESULTS: Forty-eight cases of malaria occurred among US troops while in Somalia; 41 of these cases were P falciparum. Risk factors associated with malaria included: noncompliance with recommended chemoprophylaxis (odds ratio [OR] 2.4); failure to use bed nets (OR 2.6); and failure to keep sleeves rolled down (OR 2.2). Some patients developed malaria in spite of mefloquine (n = 8) or doxycycline (n = 5) levels of compatible with chemoprophylactic compliance. Five mefloquine failures had both serum levels > or = 650 ng/mL and metabolite:mefloquine ratios over 2, indicating chemoprophylactic failure. All cases were successfully treated, including 1 patient who developed cerebral malaria. CONCLUSIONS: P falciparum malaria attack rates were substantial in the first several weeks of Operation Restore Hope. While most cases occurred because of noncompliance with personal protective measures or chemoprophylaxis, both mefloquine and doxycycline chemoprophylactic failures occurred. Military or civilian travelers to East Africa must be scrupulous in their attention to both chemoprophylaxis and personal protection measures.

Dengue fever in U.S. troops during Operation Restore Hope, Somalia, 1992-1993.

Dengue fever (DF) was considered to be a potential cause of febrile illness in U.S. troops deployed to Somalia during Operation Restore Hope in 1992-1993. A prospective study of hospitalized troops with fever and a seroepidemiologic survey of 530 troops were conducted. Among 289 febrile troops hospitalized, 129 (45%) did not have an identified cause of their fever. Dengue (DEN) virus was recovered from 41 (43%) of 96 of these patients by inoculation of admission sera into C6/36 cell cultures. Thirty-nine (41%) of the isolates were identified as DEN-2 and two (2%) as DEN-3 by an indirect immunofluorescent antibody assay. An additional 18 (49%) of 37 culture-negative cases were shown by immunoglobulin M (IgM) antibody capture enzyme-linked immunosorbent assay to have anti-DEN virus antibody. All identified DF cases recovered within 1-2 weeks; no case of dengue hemorrhagic fever or shock syndrome was observed. A seroepidemiologic survey of a unit (n = 494) with 17 culture or serologically identified DF cases and a 13% attack rate of unidentified febrile illness revealed a 7.7% prevalence of anti-DEN virus IgM antibody. Failure to use bed nets was the only identified risk factor for DEN infection (adjusted odds ratio = 2.2, 95% confidence interval = 1.4-3.0). These data indicate that DF was an important cause of febrile illness among US troops in Somalia, and demonstrate the difficulties in preventing DEN infection in troops operating in field conditions.

Diarrheal disease among military personnel during Operation Restore Hope, Somalia, 1992-1993.

The potential for widespread diarrheal disease was regarded as a substantial threat to U.S. troops participating in the early phases of Operation Restore Hope in Somalia. Outpatient surveillance of 20,859 U.S. troops deployed during the first eight weeks, however, indicated that a mean of only 0.8% (range 0.5-1.2%) of personnel sought care for diarrhea each week, and in three epidemiologic surveys, < 3% of troops reported experiencing a diarrheal illness per week. Despite these low overall attack rates, diarrhea accounted for 16% of 381 hospital admissions and 20% of 245 patients admitted with a temperature > or = 38.5 degrees C. Sixty-one specimens were obtained from inpatients and 52 were obtained from outpatients. Shigella sp. were isolated from 33%, enterotoxigenic Escherichia coli from 16%, Giardia lamblia from 4%, and rotavirus from 1% of 113 stool samples obtained from inpatient (61) and outpatient (52) troops with diarrhea. Bacterial isolates obtained in Somalia were resistant to doxycycline (78%), ampicillin (54%), and sulfamethoxazole (49%), but uniformly sensitive to ciprofloxacin. With the exception of 10 Shigella sonnei isolates that were linked epidemiologically to one eating facility, bacterial pathogens occurred sporadically and demonstrated a wide variation of serotypes and antibiotic sensitivity patterns. Additionally, three of 11 paired sera collected from persons with nausea, vomiting, and watery diarrhea demonstrated a four-fold or greater increase in titer to Norwalk virus antibody. These data indicate that large outbreaks of diarrheal disease did not occur; however, highly drug-resistant enteric bacteria, and to a lesser extent viral and parasitic pathogens, were important causes of morbidity among U.S. troops in Somalia.

Epidemiology of Norwalk virus during an outbreak of acute gastroenteritis aboard a US aircraft carrier.

A large outbreak of acute gastroenteritis occurred over a 5-week period aboard an aircraft carrier. The estimated cumulative attack rate was 13% among the 4,500-man crew. Eight percent of the crew sought medical attention, nearly all of whom missed 1 day or more of work. The risk of developing illness was 2 to 3 times greater for individuals living in more crowded sleeping quarters (> 50 persons per compartment). Occurrence of gastroenteritis was associated with a fourfold or more rise in Norwalk virus antibody levels, as measured by an enzyme-linked immunoassay utilizing a baculovirus expressed recombinant antigen. In addition, 27 nm Norwalk virus-like particles were visualized in two of six stools examined by immune electron microscopy. The presence of a low (< 1:50) or a high (> or = 1:6,400) pre-illness antibody level was associated with a lower incidence of illness. This investigation indicates that Norwalk virus can adversely impact operations of a military vessel and that crowding is a major risk factor in transmission.

Risk factors for sexually-transmitted diseases among deployed U.S. military personnel.

BACKGROUND AND OBJECTIVES: Information regarding risk factors for STD transmission is needed to assist in designing and evaluating prevention and control programs for US military populations. GOAL OF THIS STUDY: To obtain STD risk factor data among deployed U.S. military personnel. STUDY DESIGN: A questionnaire survey was administered to military personnel deployed aboard ship for six months to South America, West Africa, and the Mediterranean during 1989-1991. RESULTS: Among 1,744 male subjects (mean age, 23 years; 71% white; 96% enlisted), 49% reported prior sexual contact with a prostitute and 22% reported a history of a STD before deployment. During the subsequent six-month deployment, 42% reported sexual contact with a prostitute, 10% reported inconsistent use of condoms, and 10% acquired a new STD. By logistic regression analysis, sexual contact with a prostitute during deployment was independently associated with young age, nonwhite race/ethnicity, and being unmarried or divorced; inconsistent use of condoms was associated with Hispanic race/ethnicity. CONCLUSION: These data indicate that deployed U.S. military personnel frequently engage in high-risk sexual behavior and that there is a continued need for comprehensive and culturally-sensitive STD prevention programs.

Acute malnutrition and high childhood mortality related to diarrhea. Lessons from the 1991 Kurdish refugee crisis.

OBJECTIVE: To determine the extent, major causes, and contributory factors of high rates of morbidity and mortality among children at mountain camps along the Turkey-Iraq border during the 1991 Kurdish refugee crisis. DESIGN: A cross-sectional rapid nutrition survey among children and a retrospective mortality survey covering a 2-month period from the onset of the crisis. POPULATION STUDIED: Households of Kurdish refugees at resettlement camp 1 near Zakho in northern Iraq. MAIN OUTCOME MEASURES: Prevalence of wasting (low weight-for-height) and mean weight-for-height status, prevalence of diarrhea, and crude and age-specific mortality rates. RESULTS: Weight-for-height measurements indicated that children under 2 years of age had suffered significant (P < .001) recent malnutrition. The elevated prevalence of wasting and the reduced mean weight-for-height status in this group indicated generalized weight loss. This weight loss was likely the result of the high rates of diarrhea, which still affected 50% of the younger children at the time of survey. The crude mortality rate for all ages was 8.9 per 1000 per month (expected rate, 0.6 per 1000); two thirds of the deaths occurred among children aged 5 years or younger, and half among infants younger than 1 year. An estimated 12% of all infants died during the first 2 months of the crisis. Most deaths were due to diarrhea, dehydration, and resulting malnutrition. CONCLUSIONS: The high rates of malnutrition and mortality related to diarrhea in infants and younger children of Kurdish refugees took place rapidly despite prompt relief efforts and a previously healthy population. This experience underscores the need for early and aggressive public health management of sanitation, water sources, and diarrhea control programs to augment the traditional focus on food and medical relief during the emergency phase of a refugee crisis.

Intrapartum amniotic fluid index and neonatal acidosis. A pilot study to determine the correlation.

The purpose of a prospective study was to determine if there was a significant association between an intrapartum amniotic fluid index (AFI) < or = 5.0 cm and neonatal acidosis (umbilical arterial pH < 7.20 or metabolic acidosis [umbilical arterial pH < 7.20 and base deficit > 10 mEq/L]). In early labor 101 gravidas at > or = 37 gestational weeks underwent a four-quadrant amniotic fluid assessment; at delivery, umbilical arterial acid-base levels were determined. Among women with AFI < or = 5.0 cm as compared to those with AFI > 5.0 cm, the fetuses were more likely to have neonatal acidosis (31.2% versus 17.6%, respectively) and metabolic acidosis (25.0% versus 10.5%, respectively), although the differences were not statistically significant.