Severe Falciparum and Vivax Malaria on the Thailand-Myanmar Border: A Review of 1503 Cases.

BACKGROUND: The northwestern border of Thailand is an area of low seasonal malaria transmission. Until recent successful malaria elimination activities, malaria was a major cause of disease and death. Historically the incidences of symptomatic Plasmodium falciparum and Plasmodium vivax malaria were approximately similar. METHODS: All malaria cases managed in the Shoklo Malaria Research Unit along the Thailand-Myanmar border between 2000 and 2016 were reviewed. RESULTS: There were 80 841 consultations for symptomatic P. vivax and 94 467 for symptomatic P. falciparum malaria. Overall, 4844 (5.1%) patients with P. falciparum malaria were admitted to field hospitals, of whom 66 died, compared with 278 (0.34%) with P. vivax malaria, of whom 4 died (3 had diagnoses of sepsis, so the contribution of malaria to their fatal outcomes is uncertain). Applying the 2015 World Health Organization severe malaria criteria, 68 of 80 841 P. vivax admissions (0.08%) and 1482 of 94 467 P. falciparum admissions (1.6%) were classified as severe. Overall, patients with P. falciparum malaria were 15 (95% confidence interval, 13.2-16.8) times more likely than those with P. vivax malaria to require hospital admission, 19 (14.6-23.8) times more likely to develop severe malaria, and ≥14 (5.1-38.7) times more likely to die. CONCLUSIONS: In this area, both P. falciparum and P. vivax infections were important causes of hospitalization, but life-threatening P. vivax illness was rare.

Preventing infectious diseases for healthy ageing: The VITAL public-private partnership project.

Prevention of infectious diseases through immunisation of the growing ageing adult population is essential to improve healthy ageing. However, many licenced and recommended vaccines for this age group show signs of waning of the protective effect due to declining immune responses (immuno-senescence) and decreasing vaccine uptake. Today's major challenge is to improve vaccine effectiveness and uptake and to deploy efficient vaccination strategies for this age group. The Vaccines and InfecTious diseases in the Ageing popuLation (VITAL) project, with partners from 17 academic & research groups and public institutes as well as seven industry collaborators, aims to address this challenge. The ambition is to provide evidence-based knowledge to local decision makers. Using a holistic and multidisciplinary approach and novel analytical methods, VITAL will provide tools that allow the development of targeted immunisation programs for ageing adults in European countries. The project is based on four pillars focussing on the assessment of the burden of vaccine-preventable diseases in ageing adults, the dissection of the mechanisms underlying immuno-senescence, the analysis of the clinical and economic public health impact of vaccination strategies and the development of educational resources for healthcare professionals. By the end of the project, a clear, detailed, and integrated program should be available for implementing a consistent, affordable, and sustainable vaccination strategy for ageing adults with regular evaluations of its impact over time.

A descriptive cross-sectional study of cholera at Kakuma and Kalobeyei refugee camps, Kenya in 2018.

INTRODUCTION: cholera is a significant public health concern among displaced populations. Oral cholera vaccines are safe and can effectively be used as an adjunct to prevent cholera in settings with limited access to water and sanitation. Results from this study can inform future consideration for cholera vaccination at Kakuma and Kalobeyei. METHODS: a descriptive cross-sectional study of cholera cases at Kakuma refugee camp and Kalobeyei integrated settlement was carried out between May 2017 to May 2018 (one year). Data were extracted from the medical records and line lists at the cholera treatment centres. RESULTS: the results found 125 clinically suspected and confirmed cholera cases and one related death (CFR 0.8%). The cumulative incidence of all cases was 0.67 (95% CI=0.56-0.80) cases/1000 persons. Incidence of cholera was higher in children under the age of five 0.94(95% CI=0.63-1.36) cases/1000 persons. Children aged <5 years showed 51% increased risk of cholera compared to those aged ≥5 years (RR=1.51; 95% CI=1.00-2.31, p=0.051). Individuals from the Democratic Republic of Congo had nearly 9-fold risk of reporting cholera (RR=8.62; 95% CI=2.55-37.11, p<0.001) while individuals from South Sudan reported 7 times risk of cholera case compared to those from Somalia (RR=7.39; 95% CI=2.78-27.73, p<0.001). CONCLUSION: in addition to the improvement of water, sanitation and hygiene (WaSH), vaccination could be implemented as a short-medium term measure of preventing cholera outbreaks. Age, country of origin and settlement independently predicted the risk of cholera.

Outcomes of Clostridium difficile-suspected diarrhea in a French university hospital.

Clostridium difficile infection (CDI) produces a variety of clinical presentations ranging from mild diarrhea to severe infection with fulminant colitis, septic shock, and death. CDI puts a heavy burden on healthcare systems due to increased morbidity and mortality, and higher costs. We evaluated the clinical impact of CDI in terms of complications and mortality in a French university hospital compared with patients with diarrhea unrelated to CDI. A 3-year prospective, observational, cohort study was conducted in a French university hospital. Inpatients aged 18 years or older with CDI-suspected diarrhea were eligible to participate in the study and were followed for up to 60 days after CDI testing. Among the 945 patients with diarrhea included, 233 had confirmed CDI. Overall, 106 patients (11.2%) developed at least one of the following complications: colectomy, colitis, ileitis/rectitis, ileus, intestinal perforation, megacolon, multiorgan failure, pancolitis, peritonitis, pseudomembranous colitis, renal failure, and sepsis/septic shock. The complication rate was significantly higher in patients with diarrhea related to C. difficile than in non-CDI patients (26.6% vs 6.2%, P < 0.001). At day 60, 137 (14.5%) patients had died, with 37 deaths among the CDI group (15.9%). Death was attributable to CDI in 15 patients (6.4%). Complications are more frequent among CDI cases than in patients with diarrhea not related to C. difficile. Assessment of CDI is necessary to ensure allocation of sufficient resources to CDI prevention.

Factors associated with Clostridium difficile infection: A nested case-control study in a three year prospective cohort.

BACKGROUND: Clostridium difficile infection (CDI) is a serious medical condition that is associated with substantial morbidity and mortality. Identification of risk factors associated with CDI and prompt recognition of patients at risk is key to successfully preventing CDI. METHODS: A 3-year prospective, observational, cohort study was conducted in a French university hospital and a nested case-control study was performed to identify risk factors for CDI. Inpatients aged 18 years or older, suffering from diarrhea suspected to be related to CDI, were asked to participate. RESULTS: A total of 945 patients were included, of which 233 cases had a confirmed CDI. CDI infection was more common in men (58.4%) (P = 0.04) compared with patients with diarrhea not related to C. difficile. Previous hospitalization (P < 0.001), prior treatment with antibiotics (P = 0.001) or antiperistaltics (P = 0.002), liver disease (P = 0.003), malnutrition (P < 0.001), and previous CDI (P < 0.001) were significantly more common in patients with CDI. Multivariate logistic regression analysis showed that exposure to antibiotics in the last 60 days (especially third generation cephalosporins and penicillins with ß-lactamase inhibitor), chronic renal or liver disease, malnutrition or previous CDI, were associated with an independent high risk of CDI. Age was not related with CDI. CONCLUSIONS: This study showed that antibiotics and some comorbid conditions were predictors of CDI. Patients at high risk of acquiring CDI at the time of admission may benefit from careful monitoring of antibiotic prescriptions and early attention to infection control issues. In future, these "high-risk" patients may benefit from novel agents being developed to prevent CDI.

Adverse effects of mefloquine for the treatment of uncomplicated malaria in Thailand: A pooled analysis of 19, 850 individual patients.

Mefloquine (MQ) has been used for the treatment of malaria since the mid-1980s, first as monotherapy or as fixed combination with sulfadoxine-pyrimethamine (MSP) and since the mid-1990s in combination with artesunate. There is a renewed interested in MQ as part of a triple therapy for the treatment of multi-drug resistance P. falciparum malaria. The widespread use of MQ beyond south-East Asia has been constrained by reports of poor tolerability. Here we present the side effect profile of MQ for the treatment of uncomplicated malaria on the Thai-Myanmar/Cambodia borders. In total 19,850 patients received seven different regimens containing either 15 or 24-25 mg/kg of MQ, the latter given either as a single dose, or split over two or three days. The analysis focused on (predominantly) gastrointestinal and neuropsychiatric events as compared to the new fixed dose combination of MQ plus artesunate given as equal doses of 8 mg/kg MQ per day over three days. Gastrointestinal side effects were dose-dependent and associated with the severity of malaria symptoms. Serious neuropsychiatric side effects associated with MQ use were rare: for a single 25 mg/kg dose it was 11.9 per 10,000 treatments (95% confidence interval, CI, 4-285) vs. 7.8 (3-15) for the 15 mg/kg dose. The risk with 25 mg/kg was much higher when it was given as repeat dosing in patients who had failed treatment with 15 mg/kg MQ in the preceding month; (RR 6.57 (95% CI 1.33 to 32.4), p = 0.0077). MQ was best tolerated as 15 mg/kg or as 24 mg/kg when given over three days in combination with artesunate. We conclude that the tolerance of a single dose of MQ in the treatment of uncomplicated malaria is moderate, but can be improved by administering it as a split dose over three days.

Factors predictive of severe Clostridium difficile infection depend on the definition used.

CONTEXT: Clostridium difficile infection (CDI) produces a variety of clinical presentations ranging from mild diarrhea to severe infection with fulminant colitis, septic shock, and death. Over the past decade, the emergence of the BI/NAP1/027 strain has been linked to higher prevalence and severity of CDI. The guidelines to treat patients with CDI are currently based on severity factors identified in the literature and on expert opinion and have not been systematically evaluated. OBJECTIVE: The objective of this study was to identify factors associated with severe CDI defined according to four different severity definitions (Def): the 2010 SHEA/IDSA guidelines (Def1), the 2014 ESCMID guidelines (Def2), complicated CDI at the end of diarrhea (Def3), and our hospital-specific guidelines (white blood cell (WBC) count ≥15 × 10(9)/L, serum creatinine concentration >50% above baseline, pseudomembranous colitis, megacolon, intestinal perforation, or septic shock requiring intensive care unit admission. METHODS: A three-year cohort study was conducted in a university hospital in Lyon, France. All hospitalized (≥48 h) patients ≥18 years old, suffering from CDI, and agreeing to participate were included. Patients were followed-up for 60 days after CDI diagnosis. After bivariate regression analyses, factors associated with severe CDI during the course of disease were identified by a multivariate logistic regression. Statistical significance was reached with a two-sided p-value <0.05. RESULTS: 233 CDI patients diagnosed between 2011 and 2014 were included for a mean incidence rate of 2.15 cases/1000 hospitalized patients or 3.16 cases/10,000 patient days. Mean age was 65.3 years and 52.5% were men. Death occurred in 37 patients (15.9%) within 60 days of diagnosis. Death was related to CDI in 15 patients (40.5%). Frequency of severe CDI ranges from 11.6% to 59.2% depending on the case-definition. Factors independently associated with severe CDI were: age ≥68 years, male gender, renal disease, and serum albumin <30 g/L according to Def1 (n = 106, 45.5%); exposure to antivirals in the previous 4 weeks, renal disease, and blood neutrophils >7,5 × 10(9)/L in patients with Def2 (n = 138, 59.2%); abdominal pain, serum albumin <30 g/L, and WBC >10 × 10(9)/L according to Def3 (n = 27, 11.6%); age ≥68 years, renal disease, serum albumin <30 g/L, serum lactate dehydrogenase >248 IU/L, and blood neutrophils >7,5 × 10(9)/L were associated with severe CDI in patients with Def4 (n = 113, 48.5%). CONCLUSIONS: Our results indicate that appropriate case definition is needed for characterizing patients at risk of developing severe CDI. Our study suggest that serum albumin and the presence of renal disease, associated with severe CDI in three definitions, may be useful for identifying patients at risk of a poor outcome.

Dengue: etiology of acute febrile illness in Abidjan, Côte d'Ivoire, in 2011-2012.

BACKGROUND: The burden of dengue in Africa is not well understood. A prospective study was conducted in Abidjan, Côte d'Ivoire from December 2011 to December 2012 to estimate the proportion of dengue and malaria cases among febrile patients during a period when dengue was not known to be circulating in the region, and to describe the clinical and virological characteristics of laboratory-diagnosed dengue cases. METHODS: Blood samples were taken from febrile patients (body temperature ≥ 38°C) at two study sites. Patients with fever lasting more than 7 days, with fever of known origin and with jaundice were excluded. Thick blood film tests, ELISA for anti-dengue IgM and reverse transcription-PCR (RT-PCR) were performed. RESULTS: A total of 812 patients were enrolled (51.7% male [48.3% female]; 46.4% aged <10 years) of whom 796 (98.0%) provided IgM ELISA and RT-PCR data, and 807 (99.4%) had thick blood film results. Three (0.4%) patients had laboratory-diagnosed dengue (one with DENV-3 serotype), none of whom were diagnosed clinically, and 234 (28.8%) had confirmed malaria. CONCLUSIONS: This study suggests that dengue virus circulates in Abidjan outside an epidemic and that there should be an increase in awareness of dengue as a possible diagnosis in cases of undifferentiated fever. These results stress the importance of implementing laboratory capacity to assess dengue burden in Africa.

How do Clostridium difficile infections affect nurses' everyday hospital work: A qualitative study.

This qualitative study explored the impact of Clostridium difficile infections on nurses' everyday work in the hospital. Twelve nurses (six in France and six in the United States) were interviewed in depth using a semi-structured interview guide. Thematic analysis of the interviews was performed. Managing diarrhoea and taking precautionary measures for infection control were the two most inconvenient aspects nurses reported with C. difficile patient management. Precautions included contact isolation, hand hygiene and reorganization/coordination of nursing care and ward. Precautions were time consuming and significantly increased nurses' workload when combined with caring for patients with uncontrollable, frequent bouts of diarrhoea. Management of C. difficile infection is extremely burdensome for nurses in their everyday work and disruptive to hospital organizations as a whole. Prevention of C. difficile infections, together with coordinated team work and communication, would therefore contribute to decreasing nurses' workload and the burden to health-care facilities associated with caring for these patients.

Modeling the dynamics of Plasmodium vivax infection and hypnozoite reactivation in vivo.

The dynamics of Plasmodium vivax infection is characterized by reactivation of hypnozoites at varying time intervals. The relative contribution of new P. vivax infection and reactivation of dormant liver stage hypnozoites to initiation of blood stage infection is unclear. In this study, we investigate the contribution of new inoculations of P. vivax sporozoites to primary infection versus reactivation of hypnozoites by modeling the dynamics of P. vivax infection in Thailand in patients receiving treatment for either blood stage infection alone (chloroquine), or the blood and liver stages of infection (chloroquine + primaquine). In addition, we also analysed rates of infection in a study in Papua New Guinea (PNG) where patients were treated with either artesunate, or artesunate + primaquine. Our results show that up to 96% of the P. vivax infection is due to hypnozoite reactivation in individuals living in endemic areas in Thailand. Similar analysis revealed the around 70% of infections in the PNG cohort were due to hypnozoite reactivation. We show how the age of the cohort, primaquine drug failure, and seasonality may affect estimates of the ratio of primary P. vivax infection to hypnozoite reactivation. Modeling of P. vivax primary infection and hypnozoite reactivation provides important insights into infection dynamics, and suggests that 90-96% of blood stage infections arise from hypnozoite reactivation. Major differences in infection kinetics between Thailand and PNG suggest the likelihood of drug failure in PNG.

Incidence of dengue virus infection in school-aged children in Puerto Rico: a prospective seroepidemiologic study.

Dengue is a potentially fatal acute febrile illness caused by the mosquito-borne dengue viruses (DENV-1 to -4). To estimate DENV seroincidence in school-aged children, a 1-year prospective cohort study was conducted in Patillas, Puerto Rico; 10- to 18-year-olds (N = 345) were randomly selected from 13 public schools. At enrollment, 49.8% of the entire cohort had DENV immunoglobulin G (IgG) anti-DENV antibodies, and there were individuals with neutralizing antibodies specific to each of the four DENV. The mean age of participants with incident DENV infection was 13.4 years. The 1-year seroincidence rate was 5.6%, and 61.1% of infections were inapparent. Having IgG anti-DENV at enrollment was associated with seroincidence (risk ratio = 6.8). Acute febrile illnesses during the study period were captured by a fever diary and an enhanced and passive surveillance system in the municipios of Patillas and Guayama. In summary, at enrollment, nearly one-half of the participants had a prior DENV infection, with the highest incidence in the 10- to 11-year-olds, of which most were inapparent infections, and symptomatic infections were considered mild.

Epidemiology of Clostridium difficile: a hospital-based descriptive study in Argentina and Mexico

A prospective study was conducted in four tertiary hospitals in Argentina and Mexico in order to describe the occurrence of Clostridium difficile infection (CDI) in these settings. The objective was to evaluate the incidence of CDI in at-risk populations in Argentina (one center) and Mexico (three centers) and to further explore potential study sites for vaccine development in this region. A prospective, descriptive, CDI surveillance study was conducted among hospitalized patients aged ≥40 years who had received ≥48 h of antibiotic treatment. Stool samples were collected from those with diarrhea within 30 days after starting antibiotics and analyzed for toxins A and B by ELISA, and positive samples were further tested by toxinogenic culture and restriction endonuclease analysis type assay. Overall, 466 patients were enrolled (193 in Argentina and 273 in Mexico) of whom 414 completed the follow-up. Of these, 15/414 (3.6%) experienced CDI episodes occurring on average 18.1 days after admission to hospital and 15.9 days after the end of antibiotics treatment. The incidence rate of CDI was 3.1 (95% CI 1.7-5.2) per 1000 patient-days during hospitalization, and 1.1 (95% CI 0.6-1.8) per 1000 patient-days during the 30-day follow-up period. This study highlighted the need for further evaluation of the burden of CDI in both countries, including the cases occurring after discharge from hospital.

Epidemiology of Clostridium difficile: a hospital-based descriptive study in Argentina and Mexico.

A prospective study was conducted in four tertiary hospitals in Argentina and Mexico in order to describe the occurrence of Clostridium difficile infection (CDI) in these settings. The objective was to evaluate the incidence of CDI in at-risk populations in Argentina (one center) and Mexico (three centers) and to further explore potential study sites for vaccine development in this region. A prospective, descriptive, CDI surveillance study was conducted among hospitalized patients aged ≥40 years who had received ≥48h of antibiotic treatment. Stool samples were collected from those with diarrhea within 30 days after starting antibiotics and analyzed for toxins A and B by ELISA, and positive samples were further tested by toxinogenic culture and restriction endonuclease analysis type assay. Overall, 466 patients were enrolled (193 in Argentina and 273 in Mexico) of whom 414 completed the follow-up. Of these, 15/414 (3.6%) experienced CDI episodes occurring on average 18.1 days after admission to hospital and 15.9 days after the end of antibiotics treatment. The incidence rate of CDI was 3.1 (95% CI 1.7-5.2) per 1000 patient-days during hospitalization, and 1.1 (95% CI 0.6-1.8) per 1000 patient-days during the 30-day follow-up period. This study highlighted the need for further evaluation of the burden of CDI in both countries, including the cases occurring after discharge from hospital.

Patients' experience and perception of hospital-treated Clostridium difficile infections: a qualitative study.

BACKGROUND: Clostridium difficile is the leading cause of antibiotic-associated diarrhea and an important source of nosocomial infection. Clinical manifestations can range from mild diarrhea to lethal pseudomembranous colitis. Little is known about the burden of C. difficile infections (CDI) in patients. OBJECTIVE: This qualitative study explored the impact of hospital-treated CDI on patients' lives from the first occurrence of CDI symptoms, through their hospital stay, and after discharge. METHODS: Semi-structured interviews with 12 US and 12 French patients who had experienced CDI were conducted using an interview guide that was developed on the basis of a thorough literature review. Transcripts from these interviews were analyzed to identify concepts related to the research question. FINDINGS: CDI affected numerous aspects of patients' lives. Patients reported that the continuous, watery, and uncontrollable diarrhea characteristic of CDI had the most impact on their daily lives. Diarrhea prevented them from participating in usual daily activities; this caused the collapse of their social lives. Patients felt humiliated and embarrassed. Patients' emotional distress worsened once hospitalized; they reported feelings of loneliness and worry when placed in isolation. From discharge to the time of the interview, patients reported both psychological and physical improvement. However, despite continuing improvement, most patients reported persistent worry and fear of recurrent episodes, and they were thus more careful about their diet and hygiene. CONCLUSION: As one patient in this study explained, CDI is "the worst of everything that I've had." The emotional distress and extreme physical exhaustion associated with CDI result in a traumatic and frightening experience for patients. This trauma persists after recovery and includes lingering fears of a recurrent episode.

Challenges and prospects for dengue and malaria control in Thailand, Southeast Asia.

Despite significant advances in the search for potential dengue vaccines and new therapeutic schemes for malaria, the control of these diseases remains difficult. In Thailand, malaria incidence is falling whereas that of dengue is rising, with an increase in the proportion of reported severe cases. In the absence of antiviral therapeutic options for acute dengue, appropriate case management reduces mortality. However, the interruption of transmission still relies on vector control measures that are currently insufficient to curtail the cycle of epidemics. Drug resistance in malaria parasites is increasing, compromising malaria control and elimination. Deficiencies in our knowledge of vector biology and vectorial capacity also hinder public health efforts for vector control. Challenges to dengue and malaria control are discussed, and research priorities identified.

Microsatellite genotyping of Plasmodium vivax infections and their relapses in pregnant and non-pregnant patients on the Thai-Myanmar border.

BACKGROUND: Plasmodium vivax infections in pregnancy are associated with low birth weight and anaemia. This parasites species is also characterised by relapses, erythrocytic infections initiated by the activation of the dormant liver stages, the hypnozoites, to mature. Genotyping of P. vivax using microsatellite markers has opened the way to comparative investigations of parasite populations. The aim of the study was to assess whether there were any differences between the parasites found in pregnant and non-pregnant patients, and/or between the admission infections and recurrent episodes during follow-up. METHODS: Blood samples were collected from 18 pregnant and 18 non-pregnant patients, who had at least two recurrent episodes during follow-up, that were recruited in two previous trials on the efficacy of chloroquine treatment of P. vivax infections on the Thai-Myanmar border. DNA was purified and the P. vivax populations genotyped with respect to eight polymorphic microsatellite markers. Analyses of the genetic diversity, multiplicity of infection (MOI), and a comparison of the genotypes in the samples from each patient were conducted. RESULTS: The P. vivax parasites present in the samples exhibited high genetic diversity (6 to 15 distinct allelic variants found for the 8 loci). Similar expected heterozygosity (He) values were obtained for isolates from pregnant (0.837) and non-pregnant patients (0.852). There were modest differences between the MOI values calculated for both admission and recurrence samples from the pregnant patients (2.00 and 2.05, respectively) and the equivalent samples from the non-pregnant patients (1.67 and 1.64, respectively). Furthermore, the mean number of distinct alleles enumerated in the admission samples from the pregnant (6.88) and non-pregnant (7.63) patients were significantly lower than that found in the corresponding recurrent episodes samples (9.25 and 9.63, respectively). CONCLUSIONS: The P. vivax populations circulating in inhabitants along the Thai-Myanmar border, an area of low malaria transmission, displayed high genetic diversity. A subtle increase in the multiplicity of P. vivax infections in pregnant patients suggests a higher susceptibility to infection. The higher allelic diversity in the relapse as compared to the admission samples in both patient groups is consistent with the hypothesis that a febrile episode promotes the activation of hypnozoites.

Seroepidemiology of dengue in travellers: a paired sera analysis.

BACKGROUND: Dengue is a frequent cause of fever in travellers. The true extent is unknown as many infections are asymptomatic or undiagnosed. METHODS: We used paired sera, with pre- and post-travel specimens from Swiss travellers to tropical destinations, to evaluate the seroepidemiology of travel-related dengue. Post-travel specimens were tested for the presence of IgG and IgM antibodies to dengue antigen serotypes (1, 2, 3 and 4) using an indirect enzyme-linked immunosorbent assay (ELISA). All post-travel sera that screened as positive for dengue IgG or IgM antibodies were re-tested with the corresponding pre-travel sera as paired assays in order to detect seroconversion. RESULTS: There were 285 travellers with specimens available for analysis. Two hundred and fifty seven of the 285 individuals (90.2%) had negative dengue serology post-travel. Of the remaining 28 cases, 25 were dengue IgG positive and 3 had equivocal results. This corresponds to IgG seropositivity in 8.9%. Eighteen of these 25 individuals had a pre-travel specimen available for testing, of which 15 were positive for IgG consistent with possible past exposure. Three of the 18 had negative serology pre-travel, indicating possible recent infection. This corresponds to an attack rate of possible dengue of 1.1% and an incidence rate of 6.7 per 1000 person-months (95% CI 0-60.0). Two of these three individuals had received yellow fever vaccine for their trip, raising the potential of cross-reactivity. The confirmed dengue attack rate therefore was 0.23% with a corresponding incidence rate of 2.2 per 1000 person-months (95% CI-0-33.1). CONCLUSIONS: Seroepidemiology provides additional evidence of an appreciable risk of acute dengue infection among travellers to tropical destinations.

Low risk of Japanese encephalitis in short-term Australian travelers to Asia.

The risk of Japanese encephalitis (JE) in travelers is unknown. In this prospective study, we investigated the incidence of JE in 387 short-term Australian travelers visiting Asia over a 32-month period from August 2007 to February 2010 by performing pre- and post-travel antibody testing. No travelers were infected with JE virus during travel, indicating a low risk of infection for short-term travelers.

Incidence and risk factors for acute respiratory illnesses and influenza virus infections in Australian travellers to Asia.

BACKGROUND: Respiratory infections including influenza are a common cause of acute short-term morbidity in travellers and yet the risk of these infections is poorly defined. OBJECTIVES: To estimate the incidence density of and risk factors for acute respiratory infections (ARIs) and influenza in Australian travellers to Asia. STUDY DESIGN: Travel-clinic attendees were prospectively identified and completed questionnaires (demographic data, travel itinerary, health and vaccination history) and also provided pre and post-travel serological samples for Influenza A and B (complement fixation test). Returned travellers with an ARI provided nasopharyngeal specimens for RT-PCR identification of respiratory viruses. RESULTS: In this cohort (n = 387) of predominantly (72%) short-term travellers, 58% were female, the median age was 37 years and 69% were tourists. ARIs occurred in 109 travellers (28%) translating to an incidence of 106.4 ARIs per 10,000 traveller days (95% confidence interval CI 88.6-126.7). The traveller type of missionary or aid worker was a risk factor for acquiring an ARI (p = 0.03) and ARIs occurred early (< 30 days) in the travel period (p = 0.001). Four travellers (1%) acquired influenza A during travel translating to an incidence density of 3.4 infections per 10,000 days of travel (95% CI 1.4-8.6). Influenza vaccination was reported in 49% of travellers with a 3.5-fold higher incidence of influenza in unvaccinated travellers compared to vaccinated travellers (p = 0.883). CONCLUSIONS: This is one of the largest prospective studies estimating the incidence of respiratory infections in travellers. These findings have important implications for practitioners advising prospective travellers and for public health authorities.

Effect of early detection and treatment on malaria related maternal mortality on the north-western border of Thailand 1986-2010.

INTRODUCTION: Maternal mortality is high in developing countries, but there are few data in high-risk groups such as migrants and refugees in malaria-endemic areas. Trends in maternal mortality were followed over 25 years in antenatal clinics prospectively established in an area with low seasonal transmission on the north-western border of Thailand. METHODS AND FINDINGS: All medical records from women who attended the Shoklo Malaria Research Unit antenatal clinics from 12(th) May 1986 to 31(st) December 2010 were reviewed, and maternal death records were analyzed for causality. There were 71 pregnancy-related deaths recorded amongst 50,981 women who attended antenatal care at least once. Three were suicide and excluded from the analysis as incidental deaths. The estimated maternal mortality ratio (MMR) overall was 184 (95%CI 150-230) per 100,000 live births. In camps for displaced persons there has been a six-fold decline in the MMR from 499 (95%CI 200-780) in 1986-90 to 79 (40-170) in 2006-10, p<0.05. In migrants from adjacent Myanmar the decline in MMR was less significant: 588 (100-3260) to 252 (150-430) from 1996-2000 to 2006-2010. Mortality from P. falciparum malaria in pregnancy dropped sharply with the introduction of systematic screening and treatment and continued to decline with the reduction in the incidence of malaria in the communities. P. vivax was not a cause of maternal death in this population. Infection (non-puerperal sepsis and P. falciparum malaria) accounted for 39.7 (27/68) % of all deaths. CONCLUSIONS: Frequent antenatal clinic screening allows early detection and treatment of falciparum malaria and substantially reduces maternal mortality from P. falciparum malaria. No significant decline has been observed in deaths from sepsis or other causes in refugee and migrant women on the Thai-Myanmar border.