2013 multistate outbreaks of Cyclospora cayetanensis infections associated with fresh produce: focus on the Texas investigations.

The 2013 multistate outbreaks contributed to the largest annual number of reported US cases of cyclosporiasis since 1997. In this paper we focus on investigations in Texas. We defined an outbreak-associated case as laboratory-confirmed cyclosporiasis in a person with illness onset between 1 June and 31 August 2013, with no history of international travel in the previous 14 days. Epidemiological, environmental, and traceback investigations were conducted. Of the 631 cases reported in the multistate outbreaks, Texas reported the greatest number of cases, 270 (43%). More than 70 clusters were identified in Texas, four of which were further investigated. One restaurant-associated cluster of 25 case-patients was selected for a case-control study. Consumption of cilantro was most strongly associated with illness on meal date-matched analysis (matched odds ratio 19·8, 95% confidence interval 4·0-∞). All case-patients in the other three clusters investigated also ate cilantro. Traceback investigations converged on three suppliers in Puebla, Mexico. Cilantro was the vehicle of infection in the four clusters investigated; the temporal association of these clusters with the large overall increase in cyclosporiasis cases in Texas suggests cilantro was the vehicle of infection for many other cases. However, the paucity of epidemiological and traceback information does not allow for a conclusive determination; moreover, molecular epidemiological tools for cyclosporiasis that could provide more definitive linkage between case clusters are needed.

In-vivo efficacy of amodiaquine-artesunate in children with uncomplicated Plasmodium falciparum malaria in western Kenya.

OBJECTIVES: To assess the efficacy of amodiaquine-artesunate in an area with high chloroquine resistance in western Kenya. METHODS: Twenty-eight day in-vivo efficacy trial of amodiaquine-artesunate in 103 children aged 6-59 months in western Kenya with smear-confirmed uncomplicated Plasmodium falciparum malaria. RESULTS: The 28-day uncorrected adequate clinical and parasitological response (ACPR) was 69.0%, with 15.5% Late Clinical Failure and 15.5% Late Parasitologic Failure rates. The PCR-corrected 28-day ACPR was 90.2%. Clinical risk factors for recurrent infection (recrudescences and reinfections) were lower axillary temperature at enrollment and low weight-for-age Z-score. The presence of single nucleotide polymorphisms pfcrt 76T and pfmdr1 86Y at baseline was associated with increased risk of recurrent infections, both reinfections and recrudescences. CONCLUSION: Although artemether-lumefantrine (Coartem) is the first line ACT in Kenya, amodiaquine-artesunate is registered as an option for treatment of uncomplicated P. falciparum and remains an effective alternative to Coartem in western Kenya. Continued amodiaquine monotherapy in the private sector may jeopardize the future use of amodiaquine-artesunate as an alternative artemisinin-based combination therapy.

Daily trimethoprim-sulfamethoxazole prophylaxis rapidly induces corresponding resistance among intestinal Escherichia coli of HIV-infected adults in Kenya.

BACKGROUND: Trimethoprim-sulfamethoxazole (TMP-SMZ) has been recommended by World Health Organization (WHO) as daily prophylaxis for Africans with AIDS to prevent opportunistic infections. Daily TMP-SMZ may reduce its susceptibility to commensal intestinal Escherichia coli (E coli), increasing the burden of TMP-SMZ-resistant pathogens. METHODS: Participants received either daily TMP-SMZ (CD4 <350 cells/mm(3)) or daily multivitamins (MVIs; CD4 > or =350 cells/mm(3)) for 6 months. Stool was collected at baseline, 2 weeks, 2 months, and 6 months. A random E coli was tested for susceptibility. RESULTS: Baseline prevalence of TMP-SMZ resistance ranged from 71% to 81% and was not different across CD4 strata. At 2 weeks, prevalence of TMP-SMZ-resistant E coli increased significantly from 78% to 98% (P < .001) among persons taking daily TMP-SMZ and did not change among persons taking MVIs. CONCLUSIONS: Daily prophylaxis with TMP-SMZ induced in vivo resistance to the drug after 2 weeks. Empiric therapy for diarrhea with agents other than TMP-SMZ should be considered for HIV-infected persons receiving daily TMP-SMZ prophylaxis.

Sporadic paediatric diarrhoeal illness in urban and rural sites in Nyanza Province, Kenya.

OBJECTIVE: Investigate differences in the infectious aetiology, health seeking behaviour, and provider practices with regard to diarrhoeal illness among children presenting to urban versus rural clinics in Western Kenya. DESIGN: Laboratory-based, passive surveillance. SETTING: The urban portion of the study was conducted at the paediatric outpatient clinic of Nyanza Provincial Hospital in Kisumu. The rural portion of the study was conducted at four outpatient clinics in the Asembo Bay community approximately 20 kilometers west of Kisumu. SUBJECTS: Children aged less than five years presenting to medical facilities for the treatment of diarrhoea from October 2001-October 2003 at the urban site and May 1997-April 2003 for the rural sites. RESULTS: Among the 1303 urban and 1247 rural specimens collected, 24% of specimens yielded a bacterial pathogen (24% urban, 25% rural). Campylobacter was the predominant bacterial pathogen (17% urban, 15% rural), followed by Shigella and nontyphoidal Salmonella (both 4% urban and 5% rural). In both communities, susceptibilities of these pathogens to the most commonly prescribed antibiotics was low (< or = 50%); 70% of all episodes of diarrhoea were prescribed antibiotic treatment. Urban health practitioners prescribed fewer antibiotics, chose drugs more likely to be effective, and were more likely to prescribe oral rehydration therapy for bloody diarrhoea. CONCLUSION: Most characteristics of diarrhoeal disease and their causes were similar in paediatric patients presenting to urban and rural clinics. Urban providers were more compliant with WHO recommendations.

Causes of deaths using verbal autopsy among adolescents and adults in rural western Kenya.

OBJECTIVE: To establish causes and patterns of deaths among adolescents and adults (age >11 years) using verbal autopsy (VA) in a rural area of western Kenya where malaria and HIV are common. METHODS: Village reporters reported all deaths in Asembo and Gem (population 135 000), an area under routine demographic surveillance. After an interval of >/=1 month, a trained interviewer used a structured questionnaire to ask the caretaker about signs and symptoms that preceded death. Three clinical officers independently reviewed the interviews and assigned two unranked causes of death; a common cause was designated as the cause of death. RESULTS: In 2003, 1816 deaths were reported from residents; 48% were male and 72% were between 20 and 64 years of age. Most residents (97%) were ill before death, with 60% of illnesses lasting more than 2 months; 87% died at home. Care was sought by 96%; a health facility was the most common source, visited by 73%. For 1759 persons (97%), a common cause of death was designated. Overall, 74% of deaths were attributed to infectious causes. HIV (32%) and tuberculosis (TB) (16%) were the most frequent, followed by malaria, respiratory infections, anaemia and diarrhoeal disease (approximately 6% each). Death in a health facility was associated with young age, higher education, higher SES, a non-infectious disease cause and a shorter duration of illness. CONCLUSION: In this area, the majority of adult and adolescent deaths were attributed to potentially preventable infectious diseases. Deaths in health facilities were not representative of deaths in the community. Programmes to prevent HIV and TB infection and to decrease mortality have started. Their impact can be evaluated against this baseline information.

Impact of sustained use of insecticide-treated bednets on malaria vector species distribution and culicine mosquitoes.

Insecticide-treated bednets (ITNs) significantly reduce malaria vector populations. Susceptibility to ITNs differs by vector species, and culicine mosquitoes have not been shown to be significantly affected by the use of ITNs. We examined the impact of 2-4 yr of ITN use on malaria vector species distribution and culicine mosquitoes. Routine entomological surveillance was conducted in adjacent areas with and without ITNs from November 1999 to January 2002. Use of ITNs reduced the proportion of Anopheles gambiae Giles relative to Anopheles arabiensis Giles. The number of culicines per house was significantly lower in the ITN area than in the neighboring area. Changes in the An. gambiae sibling species distribution may help to explain apparent mosquito behavioral changes attributed to ITNs. Reductions in culicines by ITNs may have implications for community perceptions of ITN effectiveness and for control of other diseases such as lymphatic filariasis.

Angiotensin II and potassium regulate human CYP11B2 transcription through common cis-elements.

Aldosterone synthase is a mitochondrial enzyme that catalyzes the conversion of 11-deoxycorticosterone to the potent mineralocorticoid aldosterone. The gene encoding aldosterone synthase, CYP11B2, is expressed in the zona glomerulosa of the adrenal cortex. Although the major physiological regulators of aldosterone production are angiotensin II (ANG II) and potassium (K+), the mechanisms by which these compounds regulate CYP11B2 transcription are unknown. Therefore we analyzed the human CYP11B2 5'-flanking region using a transient transfection expression system in the H295R human adrenocortical cell line. ANG II and K+ increased expression of a luciferase reporter construct containing 2015 bp of human CYP11B2 5'-flanking DNA. This response was mimicked by treatment with the calcium channel activator BAYK8644, whereas activation of the protein kinase C pathway with 12-o-tetradecanoylphorbol-13-acetate had no effect. Reporter gene activity was also increased after activation of cAMP-dependent pathways by (Bu)2cAMP. Deletion, mutation, and deoxyribonuclease I footprinting analyses of the CYP11B2 5'-flanking region identified two distinct elements at positions -71/-64 (TGACGTGA) and -129/-114 (CTCCAGCCTTGACCTT) that were both required for full basal reporter gene activity and for maximal induction by either cAMP or calcium-signaling pathways. The -71/-64 element, which resembles a consensus cAMP response element (CRE), bound CRE-binding proteins from H295R cell nuclear extracts as determined by electrophoretic mobility shift analysis. Analysis of the -129/-114 element using electrophoretic mobility shift analysis demonstrated binding of the orphan nuclear receptors steroidogenic factor 1 and chicken ovalbumin upstream promoter transcription factor. These data demonstrate that ANG II, K+, and cAMP-signaling pathways utilize the same SF-1 and CRE-like cis-elements to regulate human CYP11B2 expression.

Eosinophilia-myalgia syndrome. Natural history in a population-based cohort.

BACKGROUND: To determine the natural history of eosinophilia-myalgia syndrome, we followed up all patients with eosinophilia-myalgia syndrome reported to the Oregon Health Division, Portland, during the recent epidemic caused by contaminated tryptophan. METHODS: Patients were interviewed by telephone from 1 to 5 months after illness onset and again at least 12 months after onset. Symptoms (type, onset, and duration), overall disability, treatment, and tryptophan lot and dose were assessed for each patient. RESULTS: Information was obtained for 55 (96%) of 57 case-patients: 53 patients completed interviews and two patients had died. For the 53 patients who were interviewed, symptoms with onset more commonly during the first 3 months of illness included severe myalgias, fatigue, generalized weakness, edema, and rash. Symptoms with later onset included paresthesias, muscle cramps, extremity weakness, and alopecia. At 12 months, 41 patients (77%) continued to report fatigue, 36 (68%) weakness, and 34 (64%) myalgias; 26 patients (49%) had difficulty climbing stairs, 23 (43%) had difficulty getting up from a chair, and 15 (28%) had difficulty holding a cup. Higher doses of tryptophan were correlated with more severe disability, both initially (rs = .33) and at follow-up (rs = .42). Although most patients reported improvement in symptoms at 12 months, only 14 (26%) patients reported that they were able to perform all normal daily activities. CONCLUSIONS: Most patients with eosinophilia-myalgia syndrome in this population-based cohort are still symptomatic 1 year after onset, primarily with the complaints reported early in the illness. The association between degree of disability and daily tryptophan dose suggests that ingestion of varying amounts of contaminant may be responsible, in part, for the severity of symptoms experienced by individual patients.

A multistate outbreak of Escherichia coli O157:H7 infections associated with consumption of mesclun lettuce.

BACKGROUND: An outbreak of Escherichia coli O157:H7 infections in Connecticut and Illinois during May 28 to June 27, 1996, was investigated to determine the source of infections. METHODS: Independent case-control studies were performed in both states. Pulsed-field gel electrophoresis (PFGE) was performed on E. coli O157:H7 isolates. A case-patient was defined as a Connecticut or northern Illinois resident with diarrhea whose stool culture yielded E. coli O157:H7 of the outbreak-associated PFGE subtype. Controls were town-, age-, and sex-matched to case-patients. We traced implicated lettuce to the farm level and performed environmental investigations to identify unsafe lettuce production practices. RESULTS: In Connecticut and Illinois, infection was associated with consumption of mesclun lettuce (Connecticut matched odds ratio [MOR], undefined; 95% confidence interval [CI], 3.4 to infinity; and Illinois MOR, undefined; 95% CI, 1.4 to infinity). We traced implicated lettuce to a single grower-processor. Cattle, a known E. coli O157:H7 reservoir, were found near the lettuce fields. Escherichia coli (an indicator of fecal contamination) was cultured from wash water and finished lettuce. A trace-forward investigation identified 3 additional states that received implicated lettuce; E. coli O157:H7 isolates from patients in 1 of these states matched the outbreak-associated PFGE subtype. CONCLUSIONS: This multistate outbreak of E. coli O157:H7 infections was associated with consumption of mesclun lettuce from a single producer. Molecular subtyping facilitated the epidemiological investigation. This investigation increased the knowledge about current production practices that may contribute to the contamination of lettuce by microbial pathogens. Lettuce production practices should be monitored for microbiological safety.

HIV-1 infection among women of reproductive age in a rural district in Malawi.

OBJECTIVES: To determine HIV-1 seroprevalence in pregnant women attending antenatal clinics in a rural district in Malawi, and to estimate the rate of HIV-1 infection in the district among women of reproductive age. DESIGN AND SETTING: Cross-sectional survey conducted from 1987 to 1990 of women enrolled at antenatal clinics at four sites (two towns and two villages). METHODS: Questionnaires were administered and sera screened at delivery. Population infection estimates were based on national census and survey data. RESULTS: Of 3953 pregnant women tested, 283 (7.2%) were HIV-1-seropositive. Women enrolled at town sites were significantly more likely to be HIV-1-infected than village women (11.3 versus 3.9%; P < 0.001). Higher infection rates were associated with age 20-29 years, first or second pregnancy, increased education or socioeconomic status, and living within 8 km of the clinic. It was estimated that over 7300 women of reproductive age were HIV-1-infected in this rural district. CONCLUSIONS: Seroprevalence rates in pregnant women in rural towns were intermediate between rates in villages and previously documented rates in cities in Malawi. Although village sites had lower seroprevalence rates, they accounted for over half the estimated HIV-1 infection in childbearing women in this district.

A multistate outbreak of Salmonella enterica Serotype Newport infection linked to mango consumption: impact of water-dip disinfestation technology.

Fresh produce increasingly is recognized as an important source of salmonellosis in the United States. In December 1999, the Centers for Disease Control and Prevention detected a nationwide increase in Salmonella serotype Newport (SN) infections that had occurred during the previous month. SN isolates recovered from patients in this cluster had indistinguishable pulsed-field gel electrophoresis (PFGE) patterns (which identified the outbreak strain), suggesting a common source. Seventy-eight patients from 13 states were infected with the outbreak strain. Fifteen patients were hospitalized; 2 died. Among 28 patients enrolled in the matched case-control study, 14 (50%) reported they ate mangoes in the 5 days before illness onset, compared with 4 (10%) of the control subjects during the same period (matched odds ratio, 21.6; 95% confidence interval, 3.53- infinity; P=.0001). Traceback of the implicated mangoes led to a single Brazilian farm, where we identified hot water treatment as a possible point of contamination; this is a relatively new process to prevent importation of an agricultural pest, the Mediterranean fruit fly. This is the first reported outbreak of salmonellosis implicating mangoes. PFGE was critical to the timely recognition of this nationwide outbreak. This outbreak highlights the potential global health impact of foodborne diseases and newly implemented food processes.

Risks associated with cocaine use during pregnancy.

Prenatal cocaine use has become an increasingly important public health problem in the last decade. Interpretation of epidemiologic studies designed to assess the association between cocaine use and adverse pregnancy outcomes is limited by inaccurate measurement of cocaine use, misclassification of users as non-users, confounding by socioeconomic factors, and reporting bias. Studies have consistently documented placental abruption as a maternal reproductive risk associated with cocaine use. Although suggested, less evidence is available to link cocaine use with premature rupture of membranes, spontaneous abortion, pregnancy-induced hypertension, precipitate delivery, or fetal death. Infant outcomes consistently associated with prenatal cocaine use include decreased birth weight, prematurity, and decreased fetal growth. Data on the relationship between prenatal cocaine use and congenital anomalies are limited, but one large retrospective study has documented an association between maternal cocaine use and congenital abnormalities of the urinary tract. Evidence linking prenatal cocaine use and an increased incidence of perinatal cerebral infarction or sudden infant death syndrome is lacking. Future studies should focus on the effect of maternal cocaine use on pregnancy outcome in diverse socioeconomic groups, longitudinal follow-up of exposed children, and the relationship between cocaine use and maternal behaviors that may affect access to prenatal care.

Foodborne diseases. Emerging pathogens and trends.

The epidemiology of foodborne diseases is rapidly changing. In the past 15 years, new foodborne pathogens, such as Campylobacter jejuni and Escherichia coli O157:H7, have emerged as important public health problems. Well-recognized pathogens, such as Salmonella serotype Enteritidis, have increased in prevalence or become associated with new vehicles, and pathogens such as C. jejuni and S. Typhimurium are becoming increasingly resistant to antimicrobial agents. Evolving trends in foodborne diseases are being driven by the same factors that have led to the emergence of other infectious diseases: changes in demographic characteristics of the population, human behavior, industry, and technology and the shift toward a global economy, microbial adaptation, and breakdown in the public health infrastructure. Addressing emerging foodborne disease will require more sensitive and timely surveillance, enhanced methods of laboratory identification and subtyping, and identification of effective prevention and control strategies.

Comparability of treatment groups and risk factors for parasitemia at the first antenatal clinic visit in a study of malaria treatment and prevention in pregnancy in rural Malawi.

The problems of Plasmodium falciparum infection in pregnant women have been described in numerous sub-Saharan African countries, but the frequency of parasitemia at the first antenatal visit and risk factors for infection have not been fully investigated. During a prospective antimalarial treatment and prophylaxis trial in pregnant women in Malawi (three groups receiving a chloroquine regimen and one group receiving a mefloquine regimen), we examined women at their first antenatal clinic visit to evaluate these issues and to verify that subjects in the study treatment/prevention arms were similar. Among 4,127 women with enrollment blood smear results, 1,836 (44.5%) were parasitemic. The highest infection rates and densities were observed in primigravidas (66% infected, geometric mean parasite density [GMPD] = 1,588 parasites/mm3 of whole blood), followed by second pregnancies (46% infected, GMPD = 615 parasites/mm3) and subsequent pregnancies (29% infected, GMPD = 238 parasites/mm3), (P < 10(-6) for both infection prevalence and density, by chi-square test for trend). Significant risk factors for parasitemia at first antenatal clinic visit in a multivariate model included low gravidity, high transmission season, no use of prophylaxis before first antenatal clinic visit, young age (< 20 years), human immunodeficiency virus (HIV) infection, low hematocrit, short stature, and second trimester (compared with third trimester). Women in the different treatment arms of the study were generally similar in many characteristics; statistically significant differences, where present, were small. Targeting malaria control efforts to women in their first or second pregnancy and during the high transmission season will be an important strategy to reach most parasitemic women and minimize resource expenditure. Women infected with HIV had a 55% increased risk of parasitemia at their first antenatal clinic visit and may represent an additional important risk group whose numbers may be increasing and who may benefit from identification and management for malaria.

The problem of malaria and malaria control in pregnancy in sub-Saharan Africa.

Plasmodium falciparum infection in pregnant women frequently leads to placental infection and low birth weight (< 2,500 grams) of the infant, particularly in the areas of high malaria transmission found in sub-Saharan Africa. Low birth weight is widely known to be an important risk factor for early infant mortality. To reduce the risk that maternal infection poses to child survival, many antenatal clinic programs recommend and provide antimalarial chemoprophylaxis, often with chloroquine (CQ) as a recommended element for antenatal care. Prior to the 1980s, despite widespread advocacy for this intervention, little was known about the effect of this intervention strategy. As an introduction to the Mangochi Malaria Research Project, which examined the efficacy of several antimalarial regimens using CQ or mefloquine in pregnant women in Malawi, we describe the background of knowledge regarding malaria infection in pregnant African women and the important elements of an intervention and prevention strategy.

Infant and second-year mortality in rural Malawi: causes and descriptive epidemiology.

Community information based on causes and circumstances of death in infants and young children in Malawi was obtained in a prospective cohort of babies delivered to women enrolled in a malaria-prevention-in-pregnancy study. Vital status information was obtained through home visits every two months; for children who died, questions were asked concerning age and date of death, symptoms preceding death, care sought, location of death (home versus facility), and duration of illness. Of 3,274 liveborn singleton infants, 181, 397, and 152 deaths occurred in the neonatal, postneonatal, and second year of life, respectively. For neonates, proportionate mortality was greatest for sepsis/tetanus (16.7%) and fever (8.6%); however, for more than half of neonatal deaths evaluated the cause was not identified. Up to 30% of neonatal deaths may have been related to prematurity. In the postneonatal period, gastrointestinal illness (39.6%), fever (18.3%), and respiratory illness (14.7%) were the leading causes. Most postneonatal illnesses lasted 1 week or less. Two-thirds of postneonatal deaths occurred outside of a health care facility, although 80% were brought to a facility for care during their illness. Infectious disease syndromes continued to be important in the second year of life, with gastrointestinal (31.6%), fever (23.5%), and measles (20.6%) the most commonly reported causes of death. In this area of rural sub-Saharan Africa, neonatal mortality contributes substantially to infant mortality, and prematurity is considered to be an important component of early neonatal deaths; infectious disease syndromes predominate in the postneonatal and second year of life. Strategies to reduce infant deaths in sub-Saharan Africa must consider these factors, as well as the observations that most children who died had brief illnesses, were taken to a health care facility before death, yet died at home.

Rates and risk factors for mortality during the first two years of life in rural Malawi.

Developing nations in sub-Saharan Africa experience childhood mortality rates that are much higher than any other region of the world. In a rural Malawian community we investigated risk factors for deaths occurring during the neonatal (birth-28 days), postneonatal (29-365 days), infant (birth-365 days), and second-year (366-730 days) periods among a cohort of 3,724 infants monitored from birth. The neonatal mortality rate in this cohort was 48.6 per 1,000 live births (LB); the postneonatal mortality rate was 108.7/1,000 LB. The overall infant mortality rate was 157.3 deaths/1,000 LB and the mortality rate for the first two years of life was 223.7 deaths/1,000 LB. The predominate risk factors for neonatal deaths identified in multivariate analysis were low (hazard ratio [HR] = 2.3) and very low birth weight (HR = 12.7), first pregnancy (HR = 1.8) and maternal syphilis infection (HR = 2.4). Maternal infection with human immunodeficiency virus (HIV) (HR = 1.5) predominated for postneonatal deaths. Low (HR = 1.4) and very low (HR = 5.0) birth weight, first pregnancy (HR = 1.6), maternal HIV infection (HR = 2.4), and the combination of low education and low socioeconomic status (SES) of the mother (HR = 2.0) were the most important factors during the infant period. Maternal HIV infection (HR = 3.3) and the combination of low education and low SES of the mother (HR = 2.6) were the predominate risk factors for mortality occurring during the second year. Factors that were significant in univariate analysis but not significant in the final multivariate models included prematurity, previous adverse reproductive outcome, dying during high malaria transmission season, and being born at home. Interventions to prevent maternal HIV infection and low birth weight and treatment of syphilis infection would have a great impact on reducing early childhood deaths. Improving the delivery of health care and education to women during their first pregnancy and to the most socially disadvantaged women may also help reduce the burden of early childhood mortality in communities such as the one studied in Malawi.

Imported malaria in Montagnard refugees settling in North Carolina: implications for prevention and control.

In the winter of 1992, some 402 Southeast Asian refugees were resettled in North Carolina. They received very limited medical screening before immigration and many arrived in the United States with significant health problems, including several tropical infectious diseases. These refugees had lived for many years in remote areas along the Vietnam-Cambodia border, where there is intense transmission of malaria, including Plasmodium falciparum resistant to most antimalarial drugs available in the United States. Of 322 refugees screened after arrival in North Carolina, 187 (58%) were infected: 33% with P. falciparum, 23.5% with P. vivax, 23.5% with P. malariae, and 2.1% with P. ovale. Most infected persons were asymptomatic and infections with multiple species were common. Because of the documented high infection prevalence and the probable presence of many subpatent infections, all nonpregnant refugees were treated with halofantrine; those with P. vivax or P. ovale infections were given primaquine as well. This group accounted for the largest cluster of malaria cases reported in the United States in the last 50 years. Their rapid relocation, with minimal medical screening prior to arrival, resulted in a significant burden to the refugees and to the health-care system. Coordination between immigration agencies, the public health community, and medical workers in communities where the refugees are settled is critical for U.S.-based management of imported tropical diseases.

Transmission of epidemic Vibrio cholerae O1 in rural western Kenya associated with drinking water from Lake Victoria: an environmental reservoir for cholera?

Sub-Saharan Africa has the highest reported cholera incidence and mortality rates in the world. In 1997, a cholera epidemic occurred in western Kenya. Between June 1997 and March 1998, 14,275 cholera admissions to hospitals in Nyanza Province in western Kenya were reported. There were 547 deaths (case fatality rate = 4%). Of 31 Vibrio cholerae O1 isolates tested, all but one were sensitive to tetracycline. We performed a case-control study among 61 cholera patients and age-, sex-, and clinic-matched controls. Multivariate analysis showed that risk factors for cholera were drinking water from Lake Victoria or from a stream, sharing food with a person with watery diarrhea, and attending funeral feasts. Compared with other diarrheal pathogens, cholera was more common among persons living in a village bordering Lake Victoria. Cholera has become an important public health concern in western Kenya, and may become an endemic pathogen in the region.

Malaria parasite infection during pregnancy and at delivery in mother, placenta, and newborn: efficacy of chloroquine and mefloquine in rural Malawi.

Despite international recommendations to use malaria treatment and prevention in pregnant women in malaria-endemic areas, few studies have evaluated the efficacy of available antimalarial regimens. This issue is of particular concern in the face of spreading chloroquine (CQ)-resistance of Plasmodium falciparum in malarious areas of sub-Saharan Africa. In a prospective trial in rural Malawian pregnant women, we examined three regimens using CQ (including the existing national policy regimen) and one regimen using mefloquine (MQ). The efficacy of the regimens was determined by comparing rates of clearance of initial parasitemia; prevention of breakthrough infection; and parasitemia at delivery in maternal peripheral blood, placental blood, and in infant umbilical cord blood. Among 1,528 parasitemic women at enrollment, 281 (18.4%) had persistent infections; and among 1,852 initially aparasitemic women, 320 (17.3%) had breakthrough parasitemia on one or more follow-up visits. Compared with women on MQ, women on a CQ regimen were at significantly greater risk of persistent and breakthrough infection (odds ratios [OR] = 30.9 and 11.1, respectively, P < 10(-6)). Other significant risk factors for persistent and breakthrough infections in a multivariate model included first pregnancy; enrollment in the rainy or postrainy season; maternal age < or = 25 years; seropositivity to the human immunodeficiency virus (HIV) (persistent infections only); and no use of antimalarial prophylaxis before enrollment (breakthrough infections only). At delivery, compared with women on MQ, women on a CQ regimen were at significantly greater risk of peripheral, placental, or umbilical cord blood parasitemia (OR = 8.7, 7.4, and 4.1, respectively, P < 10(-6)). Additional risk factors for parasitemia at delivery in multivariate models included first pregnancy; delivery in the rainy or postrainy season; HIV-seropositivity; and maternal age < or = 25 years (risk for peripheral and placental blood parasitemia only). Maternal anemia (hematocrit < 30%) at enrollment or at delivery was not associated with persistent or breakthrough parasitemia or parasitemia at deliver in these multivariate models. While factors leading to increased malaria parasite exposure (high transmission seasons) and lowered or altered host immune response (low pregnancy number, young age, and HIV infection) are important risk factors for malaria in pregnant women, the use of an ineffective intervention (CQ in a setting with CQ-resistant parasites) was the most important determinant of P. falciparum parasitemia in these pregnant women. Strategies to reduce the impact of malaria in pregnant women must use efficacious interventions and may need to consider targeting the intervention to the most susceptible women during the seasons of high malaria exposure.

PIP: During September 1987 to June 1990, 3380 pregnant women with parasitemia attending 4 prenatal care clinics in rural Mangochi District, Malawi, were assigned to 1 of 4 regimens of antimalarial treatment and/or prophylaxis. The women were followed through delivery to determine the antimalarial drug efficacy on peripheral parasitemia during pregnancy and parasitemia at the time of delivery in peripheral, placental, and umbilical cord blood. The regimens were 3 regimens for chloroquine (CQ), 1 of which was the current standard of care in Malawi, and a mefloquine (MQ) regimen. Parasite clearance was not achieved in 18.4% of the 1528 women with parasitemia at enrollment. 17.3% of the 1852 women who were aparasitemic at enrollment had breakthrough infections. Women using a CQ regimen faced a significantly greater risk of persistent and breakthrough parasitemia (odds ratio [OR ] = 30.9 and 11.1, respectively; p 0.0000001). The multivariate analysis found other significant risk factors for malaria to be first pregnancy (OR = 3.6 for persistent malaria and 1.5 for breakthrough malaria), enrollment in the rainy or post-rainy season (OR = 2-3.4 for persistent parasitemia and 1.2-2.7 for breakthrough malaria), maternal age of at most 25 years (OR = 2.3 for persistent malaria and 1.6 for breakthrough malaria), and seropositivity to HIV (OR = 1.9 for persistent malaria). At delivery, women on a CQ regimen faced a significantly higher risk of peripheral, placental, or umbilical cord parasitemia than those using MQ (OR = 8.7, 7.4, and 4.1, respectively; p 0.000001). In the multivariate model, other significant risk factors for malaria at delivery were first pregnancy, enrollment in the rainy or post-rainy season, maternal age of at most 25 years, and seropositivity to HIV. The most important determinant of falciparum malaria in pregnant women was use of an ineffective intervention (i.e., CQ in an area with CQ-resistant parasites). Based on these findings, the researchers recommend that antimalarial programs focus on highly efficacious drugs and targeting pregnant women during the season of high malaria exposure.