Showing papers in "American Journal of Tropical Medicine and Hygiene in 2008"
TL;DR: This paper reviews the current management procedures of CE with particular emphasis on the evidence base and setting-specific problems, and concludes that studies carried out in either of the two fundamentally different environments lack external validity.
Abstract: Clinical management of cystic echinococcosis (CE) has evolved over decades without adequate evaluation of important features such as efficacy, effectiveness, rate of adverse reactions, relapse rate, and cost. CE occurs in health care environments as different as Europe/North America and resource-poor countries of the South and the East. This creates setting-specific problems in the management of patients. Furthermore, studies carried out in either of the two fundamentally different environments lack external validity, i.e., results obtained in one setting may be different from those in the other and practices that can work in one may not be applicable to the other. In this paper, we review the current management procedures of CE with particular emphasis on the evidence base and setting-specific problems.
296 citations
TL;DR: A biology-driven model to assess the potential impact of rising temperature on the transmission of schistosomiasis in China found a temperature threshold of 15.4 degrees C for development of Schistosoma japonicum within the intermediate host snail, and a temperature of 5.8 degrees C at which half the snail sample investigated was in hibernation.
Abstract: Appraisal of the present and future impact of climate change and climate variability on the transmission of infectious diseases is a complex but pressing public health issue. We developed a biology-driven model to assess the potential impact of rising temperature on the transmission of schistosomiasis in China. We found a temperature threshold of 15.4°C for development of Schistosoma japonicum within the intermediate host snail (i.e., Oncomelania hupensis), and a temperature of 5.8°C at which half the snail sample investigated was in hibernation. Historical data suggest that the occurrence of O. hupensis is restricted to areas where the mean January temperature is above 0°C. The combination of these temperature thresholds, together with our own predicted temperature increases in China of 0.9°C in 2030 and 1.6°C in 2050 facilitated predictive risk mapping. We forecast an expansion of schistosomiasis transmission into currently non-endemic areas in the north, with an additional risk area of 783,883 km2 by 2050, translating to 8.1% of the surface area of China. Our results call for rigorous monitoring and surveillance of schistosomiasis in a future warmer China.
283 citations
TL;DR: The seroprevalence findings suggested that the outbreak was widespread, affecting 75% of the Lamu population; extrapolating the findings to the entire population, 13,500 (95% CI, 12,458-14328) were affected.
Abstract: An outbreak of Chikungunya virus (CHIKV) disease associated with high fever and severe protracted arthralgias was detected in Lamu, Kenya, peaking in July 2004. At least 1,300 cases were documented. We conducted a seroprevalence study to define the magnitude of transmission on Lamu Island. We conducted a systematic cross-sectional survey. We administered questionnaires and tested 288 sera from Lamu residents for IgM and IgG antibodies to CHIKV. Chikungunya virus infection (seropositivity) was defined as a person with IgG and/or IgM antibodies to CHIKV. IgM antibodies to CHIKV were detected in 18% (53/288) and IgG antibodies in 72% (206/288); IgM and/or IgG antibodies were present in 75% (215/288). The seroprevalence findings suggested that the outbreak was widespread, affecting 75% of the Lamu population; extrapolating the findings to the entire population, 13,500 (95% CI, 12,458-14328) were affected. Vector control strategies are needed to control the spread of this mosquito-borne infection.
277 citations
TL;DR: Sera from participants in the Third National Health and Nutrition Examination Survey (1988-1994) were tested for antibodies to Toxocara, and increased Toxcara seropositivity was associated with head of household level of education (low versus high) and poverty, as well as with elevated blood lead concentrations.
Abstract: To estimate the prevalence of Toxocara spp. infection in a representative sample of the United States population >or= 6 years of age, sera from participants in the Third National Health and Nutrition Examination Survey (1988-1994) were tested for antibodies to Toxocara. Among the 30,930 persons selected for the survey, 82% (N = 25,733) were interviewed, and 91% (N = 23,527) of those interviewed underwent physical examination of which 87% (N = 20,395) were tested. The age adjusted Toxocara seroprevalence was 13.9% (95% confidence intervals [CI] 12.5, 15.3), and was higher in non-Hispanic blacks (21.2%) than non-Hispanic whites (12%) or Mexican Americans (10.7%; P < 0.001). Increased Toxocara seropositivity was associated with head of household level of education (low versus high) (odds ratio [OR]: 2.2; CI: 1.8, 2.8), poverty (OR: 1.5; CI: 1.3, 1.8), elevated blood lead concentrations (OR: 1.4; CI: 1.1, 1.9), and dog ownership (OR: 1.2; CI: 1.1, 1.4). Toxocara infection is widespread and associated with specific risk groups.
230 citations
TL;DR: The results underscore the risk for epidemic dengue and DHF in the Texas-Mexico border region and identify risk factors associated with infection.
Abstract: A dengue-2 epidemic causing dengue hemorrhagic fever (DHF) occurred in the contiguous border cities of Matamoros, Tamaulipas (Mexico), and Brownsville, TX, in 2005. In December, we conducted a household-based epidemiologic survey to determine the incidence and seroprevalence of dengue infection among Matamoros and Brownsville residents and to identify risk factors associated with infection. Antibodies to dengue were measured in 273 individuals. The estimated incidence of recent dengue infection was 32% and 4% among Matamoros and Brownsville participants, respectively. The estimated prevalence of past dengue infection was 77% and 39% among Matamoros and Brownsville participants, respectively. The Breteau index was 28 in Matamoros and 16 in Brownsville, reflecting an abundant winter population of Aedes mosquitoes. Discarded waste tires and buckets were the two largest categories of infested containers found in both cities. Our results underscore the risk for epidemic dengue and DHF in the Texas-Mexico border region.
183 citations
TL;DR: The Box-Jenkins approach is used to fit an autoregressive integrated moving average (ARIMA) model to dengue incidence in Rio de Janeiro, Brazil, from 1997 to 2004 and indicates that ARIMA models are useful tools for monitoring d Dengue incidence.
Abstract: We use the Box-Jenkins approach to fit an autoregressive integrated moving average (ARIMA) model to dengue incidence in Rio de Janeiro, Brazil, from 1997 to 2004. We find that the number of dengue cases in a month can be estimated by the number of dengue cases occurring one, two, and twelve months prior. We use our fitted model to predict dengue incidence for the year 2005 when two alternative approaches are used: 12-steps ahead versus 1-step ahead. Our calculations show that the 1-step ahead approach for predicting dengue incidence provides significantly more accurate predictions (P value=0.002, Wilcoxon signed-ranks test) than the 12-steps ahead approach. We also explore the predictive power of alternative ARIMA models incorporating climate variables as external regressors. Our findings indicate that ARIMA models are useful tools for monitoring dengue incidence in Rio de Janeiro. Furthermore, these models can be applied to surveillance data for predicting trends in dengue incidence.
183 citations
TL;DR: Based on the clinical and pathologic similarities with chikungunya virus infection in humans, young ICR and CD-1 mice offer a useful and realistic model for further study of the pathogenesis and treatment of CHIKV infection.
Abstract: Newborn and 14-day-old mice inoculated subcutaneously with chikungunya virus (CHIKV) developed lethargy, difficulty walking, dragging of hind limbs, and reduced weight gain within 7-10 days after infection (PI). During the initial 6-7 days PI, the animals had viremia; high levels (10(6)-10(8) PFU) of CHIKV were also present in leg muscle. The virus persisted in muscle for several days after viremia disappeared. The major histopathologic changes were in skeletal muscle, which were focal necrosis and inflammation, followed by fibrosis and dystrophic calcification. Some mice also showed dystrophic calcification in the joint cartilage, but there were few deaths, and most of the animals eventually recovered. CHIKV antigen was shown by immunohistochemistry in the muscle for several weeks after infection. Based on the clinical and pathologic similarities with CHIKV infection in humans, young ICR and CD-1 mice offer a useful and realistic model for further study of the pathogenesis and treatment of CHIKV infection.
175 citations
TL;DR: The information supports the evidence of water-borne transmission in this population of schoolchildren and identifies one water sample as subtype 1, which had a nucleotide sequence of small subunit (SSU) ribosomal RNA (rRNA) gene that was 100% identical to that of Blastocystis infected in schoolchildren.
Abstract: In January 2005, a survey of intestinal parasitic infections was performed in a primary school, central Thailand. Of 675 stool samples, Blastocystis was identified with a prevalence of 18.9%. Genetic characterization of Blastocystis showed subtype 1 (77.9%) and subtype 2 (22.1%). Study of the water supply in this school was performed to find the possible sources of Blastocystis. Blastocystis from one water sample was identified as subtype 1, which had a nucleotide sequence of small subunit (SSU) ribosomal RNA (rRNA) gene that was 100% identical to that of Blastocystis infected in schoolchildren. Our information supports the evidence of water-borne transmission in this population.
162 citations
TL;DR: Testing the hypothesis that body size alters the susceptibility of Aedes aegypti and Aedes albopictus mosquitoes to dengue virus infection and subsequent dissemination throughout the body of the mosquito found smaller-sized females were significantly more likely to become infected and to disseminate virus than larger individuals.
Abstract: The size of arthropod vectors may affect their ability to transmit pathogens. Here we test the hypothesis that body size alters the susceptibility of Aedes aegypti and Aedes albopictus mosquitoes to dengue virus (DENV) infection and subsequent dissemination throughout the body of the mosquito. After feeding on blood containing known quantities of virus, smaller-sized females were significantly more likely to become infected and to disseminate virus than larger individuals. The effects of size were stronger for Ae. aegypti and independent of rearing conditions. Ae. albopictus was more susceptible to DENV infection and had higher virus titer in the body than Ae. aegypti, yet infected Ae. aegypti disseminated DENV more readily than infected Ae. albopictus. These results are consistent with the concept that Ae. aegypti is a more competent vector of DENV and emphasize the importance of body size in determining adult infection parameters.
152 citations
TL;DR: Even after efficacy was demonstrated within their community and an aggressive sophisticated marketing approach, few households purchased flocculant-disinfectant for point-of-use water treatment, and neither being randomized to the intervention group during the efficacy study nor combined spending on laundry soap, toothpaste, and hand soap in the preceding week was associated with active repeat use.
Abstract: In an earlier study in rural Guatemala, 257 households that received flocculant-disinfectant to treat their drinking water had 39% less diarrhea than 257 control households. Three weeks after completion of the study, national marketing of the flocculant-disinfectant was extended into the study communities. Six months later, we assessed frequency of and characteristics associated with purchase and use of the flocculant-disinfectant by revisiting the original study households and administering a questionnaire. Four hundred sixty-two households (90%) completed the follow-up survey; 22 households (5%) purchased the flocculant-disinfectant within the preceding 2 weeks and used it within the last week. Neither being randomized to the intervention group during the efficacy study nor combined spending on laundry soap, toothpaste, and hand soap in the preceding week was associated with active repeat use. Even after efficacy was demonstrated within their community and an aggressive sophisticated marketing approach, few households purchased flocculant-disinfectant for point-of-use water treatment.
152 citations
TL;DR: Multivariate regression analysis showed that gastrointestinal symptoms and other unusual manifestations were independent associated with DENV-2 infection, whereas cough and DHF/DSS features were independently associated with secondary immune response.
Abstract: Martinique experienced a dengue outbreak with co-circulation of DENV-2 and DENV-4. In an emergency department-based study, we analyzed whether the clinical presentation and outcome of adult patients were related to serotype, immune status, or plasma viral load. Of the 146 adult patients who had confirmed dengue infection, 91 (62.3%) were classified as having classic dengue fever, 11 (7.5%) fulfilled World Health Organization criteria for dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), 21 other patients (14.4%) presented with at least one typical feature of DHF/DSS [i.e., internal hemorrhage, plasma leakage, marked thrombocytopenia (platelet count < or = 50,000 platelets/mm(3)) and/or shock], and 23 further patients (15.8%) had unusual manifestations. Four patients died. Severe illness was more frequent in patients with secondary dengue infection (odds ratio, 7.18; 95% confidence interval, 3.1-16.7; P < 0.001). Multivariate regression analysis showed that gastrointestinal symptoms and other unusual manifestations were independently associated with DENV-2 infection, whereas cough and DHF/DSS features were independently associated with secondary immune response. A high plasma viral load was associated with DENV-2 infection, increased serum liver enzymes, and with DHF/DSS features in patients presenting after the third day of illness. The most severe cases of dengue resulted from the combined effects of DENV-2 and secondary infection.
TL;DR: Households using either filter reported significantly less diarrheal disease during the study compared with a control group of households without filters as indicated by longitudinal prevalence ratios.
Abstract: A randomized, controlled intervention trial of two household-scale drinking water filters was conducted in a rural village in Cambodia. After collecting four weeks of baseline data on household water quality, diarrheal disease, and other data related to water use and handling practices, households were randomly assigned to one of three groups of 60 households: those receiving a ceramic water purifier (CWP), those receiving a second filter employing an iron-rich ceramic (CWP-Fe), and a control group receiving no intervention. Households were followed for 18 weeks post-baseline with biweekly follow-up. Households using either filter reported significantly less diarrheal disease during the study compared with a control group of households without filters as indicated by longitudinal prevalence ratios CWP: 0.51 (95% confidence interval [CI]: 0.41-0.63); CWP-Fe: 0.58 (95% CI: 0.47-0.71), an effect that was observed in all age groups and both sexes after controlling for clustering within households and within individuals over time.
TL;DR: Elevated cerebrospinal fluid but not serum TNF-alpha levels on admission were associated with an increased risk of neurologic deficits 3 months later and correlated negatively with age-adjusted scores for attention, working memory, and working memory 6 months later.
Abstract: Cerebrospinal fluid (CSF) and serum levels of 12 cytokines or chemokines important in central nervous system (CNS) infections were measured in 76 Ugandan children with cerebral malaria (CM) and 8 control children. As compared with control children, children with cerebral malaria had higher cerebrospinal fluid levels of interleukin (IL)-6, CXCL-8/IL-8, granulocyte-colony stimulating factor (G-CSF), tumor necrosis factor-alpha (TNF-alpha), and IL-1 receptor antagonist. There was no correlation between cerebrospinal and serum cytokine levels for any cytokine except G-CSF. Elevated cerebrospinal fluid but not serum TNF-alpha levels on admission were associated with an increased risk of neurologic deficits 3 months later (odds ratio 1.55, 95% CI: 1.10, 2.18, P = 0.01) and correlated negatively with age-adjusted scores for attention (Spearman rho, -0.34, P = 0.04) and working memory (Spearman rho, -0.32, P = 0.06) 6 months later. In children with cerebral malaria, central nervous system TNF-alpha production is associated with subsequent neurologic and cognitive morbidity.
TL;DR: There is an urgent need for the development of alternative quality control procedures for rapid diagnostic tests that can be performed at the facility level based on poor quality blood smear staining.
Abstract: Rapid diagnostic tests (RDTs) represent an alternative to microscopy for malaria diagnosis and have shown high sensitivity and specificity in a variety of study settings. Current World Health Organization (WHO) guidelines for quality control of RDTs provide detailed instructions on pre-field testing, but offer little guidance for quality assurance once RDTs are deployed in health facilities. From September 2006 to April 2007, we introduced a histidine-rich protein II (HRP2)-based RDT (Paracheck) for suspected malaria cases five years of age and older in nine health facilities in Rufiji District, Tanzania, to assess sensitivity and specificity of RDTs in routine use at rural health facilities. Thick blood smears were collected for all patients tested with RDTs and stained and read by laboratory personnel in each facility. Thick smears were subsequently reviewed by a reference microscopist to determine RDT sensitivity and specificity. In all nine health facilities, there were significant problems with the quality of staining and microscopy. Sensitivity and specificity of RDTs were difficult to assess given the poor quality of routine blood smear staining. Mean operational sensitivity of RDTs based on reference microscopy was 64.8%, but varied greatly by health facility, range 18.8-85.9%. Sensitivity of RDTs increased with increasing parasite density. Specificity remained high at 87.8% despite relatively poor slide quality. Institution of quality control of RDTs based on poor quality blood smear staining may impede reliable measurement of sensitivity and specificity and undermine confidence in the new diagnostic. There is an urgent need for the development of alternative quality control procedures for rapid diagnostic tests that can be performed at the facility level.
TL;DR: The two conclusions from this work are that oral miltefosine can be used for cutaneous disease in this part of Bolivia and that milteFosine was more effective for L. braziliensis in this region than for L.'smania brazilensis in Guatemala.
Abstract: Oral miltefosine (2.5 mg/kg/d for 28 days) was compared with intramuscular antimony (20 mg/kg/d for 20 days) in the treatment of cutaneous leishmaniasis caused by Leishmania braziliensis in Palos Blancos, Bolivia. The cure rates with 6 months of follow-up were statistically similar: 36 of 41 evaluable miltefosine patients (88%) versus 15 of 16 (94%) evaluable antimony patients. However, antimony cured more rapidly, because, by 1 month after therapy, 31 of 44 miltefosine patients (70%) compared with 16 of 16 antimony patients (100%) had achieved cure. The two conclusions from this work are that oral miltefosine can be used for cutaneous disease in this part of Bolivia and that miltefosine was more effective for L. braziliensis in this region than for L. braziliensis in Guatemala. Chemotherapy needs to be evaluated in each endemic region, even if the "same" species of Leishmania causes disease in these locales.
TL;DR: From 1999-2007, the most common causes of neuroinvasive arboviral disease in the United States, after West Nile virus (WNV), were California (CAL) serogroup viruses, St. Louis encephalitis virus (SLEV), and eastern equine encephalopathy virus (EEEV).
Abstract: From 1999-2007, the most common causes of neuroinvasive arboviral disease in the United States, after West Nile virus (WNV), were California (CAL) serogroup viruses, St. Louis encephalitis virus (SLEV), and eastern equine encephalitis virus (EEEV). The CAL serogroup virus disease was primarily reported from Appalachia and the upper Midwest, SLEV disease from southern states, and EEEV disease from areas along the Atlantic and Gulf coasts. Children accounted for 88% of CAL serogroup virus disease, whereas 75% of SLEV disease occurred among older adults. The EEEV disease had the highest case-fatality rate (42%). The incidence of CAL serogroup virus and EEEV disease remained stable before and after the detection of WNV in the United States in 1999. The SLEV disease declined 3-fold after 1999; however, SLEV disease has occurred in sporadic epidemics that make trends difficult to interpret. The CAL serogroup virus, SLEV, and EEEV disease are persistent public health concerns in the United States warranting ongoing prevention efforts.
TL;DR: It is suggested that both skin and nasal epithelia of untreated MB leprosy patients contribute to the shedding of M. leprae into the environment and contacts of untreatedMB cases are at risk for contact with M.LePrae through both the nasal mucosa and exposed surfaces of their skin.
Abstract: It is generally held that dissemination of Mycobacterium leprae is from nasal mucosa and not through the skin of infected patients. In this study, we evaluated M. leprae in the unbroken skin and nasal secretions of multibacillary (MB) leprosy patients and their contacts. Specimens were examined by direct microscopy and polymerase chain reaction (PCR) for M. leprae DNA. Results showed that 60% of untreated MB leprosy patients examined histologically had acid-fast bacilli in the keratin layer. By PCR studies it was found that 80% of the patients had M. leprae DNA in skin washings and 60% had M. leprae DNA on swabs obtained from the nasal mucosa. Ninety-three contacts of the untreated MB cases were also tested for exposure to M. leprae by analyzing skin washings and nasal secretions by PCR. PCR analysis showed significant skin (17% positive) and nasal muscosal (4%) exposure in contacts before instituting treatment of the index cases. After 2 months of treating the index cases, all contacts tested were negative for M. leprae DNA. These data suggested that both skin and nasal epithelia of untreated MB leprosy patients contribute to the shedding of M. leprae into the environment and contacts of untreated MB cases are at risk for contact with M. leprae through both the nasal mucosa and exposed surfaces of their skin.
TL;DR: It is shown that leptospirosis is endemic in Khammouane Province and that local flooding plays an important role in the transmission of the disease.
Abstract: A cross-sectional seroprevalence study on leptospirosis, using microscopic agglutination test (MAT), was conducted in rural villages in Khammouane Province, Lao People's Democratic Republic, in December 2006. The overall prevalence of leptospiral infection among 406 subjects was 23.9% (95% confidence interval [CI] 19.7-28.0%). Independent risk factors for the infection, identified by multivariate logistic regression, were male sex (odds ratio [OR], 1.92; 95% CI: 1.24-2.98), recent flooding on one's own property (OR, 2.12; 95% CI: 1.25-3.58), and collecting wood in the forest (OR, 1.90; 95% CI: 1.17-3.09). Age, occupation, and animal ownership were not associated with seropositivity. Flooding was associated with the risk of infection particularly for women, whose behaviors or activities involving contact with floodwater were presumed to play an important role. This study showed that leptospirosis is endemic in Khammouane Province and that local flooding plays an important role in the transmission of the disease.
TL;DR: Serologic findings with highest titer against Leptospira interrogans serovar Copenhageni did not show significant differences between survivors and non-survivors, and lung involvement was an important predictor of death in leptospirosis in São Paulo, of relevance in lepsis-endemic regions where this complication is common.
Abstract: To ascertain prognostic factors associated with fatal outcomes in severe leptospirosis, a retrospective case-control study was done using population-based surveillance data. Centralized death certificate reporting of leptospirosis mortality was combined with details of patients’ hospitalizations, which were obtained from hospitals representing all sectors of Sao Paulo city. Among identified leptospirosis cases, 89 lethal cases and 281 survivor cases were analyzed. Predictors of death included age > 40 years, development of oliguria, platelet count 3 mg/dL, and pulmonary involvement. The latter was the strongest risk factor with an estimated odds ratio of 6.0 (95% confidence interval: 3.0–12.0). Serologic findings with highest titer against Leptospira interrogans serovar Copenhageni did not show significant differences between survivors and non-survivors. Lung involvement was an important predictor of death in leptospirosis in Sao Paulo, of relevance in leptospirosis-endemic regions where this complication is common.
TL;DR: Examination of 3 instead of 1 stool specimen increased the sensitivity of helminth diagnosis, most notably for hookworm, and calls for control measures.
Abstract: Intestinal multiparasitism, the accuracy of different diagnostic techniques, and the influence of sampling effort were studied among 215 individuals in a Bulang village, Yunnan province, People's Republic of China. Behavioral, demographic, and socioeconomic data were obtained by questionnaire. Multiple stool specimens were examined by the Kato-Katz, Koga agar plate, Baermann, and ether-concentration methods. Eight helminth and 7 protozoa species were diagnosed. The prevalence of each of the 3 main soil-transmitted helminths (Ascaris lumbricoides, hookworm, and Trichuris trichiura) exceeded 85%. Blastocystis hominis was the most prevalent intestinal protozoan (20.0%). Over 80% of the individuals harbored 3 or more intestinal parasites concurrently. The infection intensities were predominantly light for hookworm and T. trichiura but moderate for A. lumbricoides. Examination of 3 instead of 1 stool specimen increased the sensitivity of helminth diagnosis, most notably for hookworm. Intestinal multiparasitism is rampant in this rural part of Yunnan province and calls for control measures.
TL;DR: These findings demonstrate alterations in clinical features and phenotypic changes of major bacterial pathogens in the recent Bangladesh flood.
Abstract: Bangladesh experienced severe flooding and diarrheal epidemics in 2007. We compared flood data from 2007 with 2004 and 1998 for diarrheal patients attending the ICDDR,B hospital in Dhaka. In 2007, Vibrio cholerae O1 (33%), rotavirus (12%), and enterotoxigenic Escherichia coli (ETEC) (12%) were most prevalent. More severe dehydration was seen in 2007 compared with 2004 and 1998 (P < 0.001). In 2007, V. cholerae O1 Inaba (52%) and Ogawa (48%) were seen, whereas in 2004 and 1998 it was primarily Inaba and the Ogawa types, respectively (P < 0.001). In 2007, 51% of ETEC produced the heat labile toxin (LT) (P < 0.001 compared with 2004), 22% expressed the heat stable (ST) (P < 0.001), and 27% were ST/LT positive (P = 0.231). The CS7 colonization factor (CF) was the most prevalent in 2007 (20% compared with 6% in 2004; P = 0.05). Our findings demonstrate alterations in clinical features and phenotypic changes of major bacterial pathogens in the recent Bangladesh flood.
TL;DR: It is demonstrated that only some genotypes of B. burgdorferi present in ticks have a high propensity to disseminate in humans, and these are ranked by their probability of disseminating from ticks to the blood of humans.
Abstract: Lineages of Borrelia burgdorferi, the bacterium that causes Lyme disease, can be characterized by distinct alleles at the outer surface protein C (ospC) locus. The lineages marked by ospC genotypes have been shown to be differentially invasive in different species of mammals, including humans; genotypes A, B, I, and K effectively disseminate to human blood and cerebrospinal fluid. In this report, we extend the sample of genotypes isolated from human blood to include genotypes N, H, C, M, and D, and rank each by their probability of disseminating from ticks to the blood of humans. Our results demonstrate that only some genotypes of B. burgdorferi present in ticks have a high propensity to disseminate in humans.
TL;DR: Elderly individuals with dengue hemorrhagic fever had significantly lower incidences of fever, but also had higher frequencies of concurrent bacteremia, chronic obstructive pulmonary disease, and acute renal failure, and a higher fatality rate compared with non-elderly adults.
Abstract: To better understand the clinical and laboratory characteristics and to identify risk factor(s) for fatality in elderly patients with dengue hemorrhagic fever (DHF), 66 elderly (age > or = 65 years) and 241 non-elderly adults (age, 19-64 years) with DHF were retrospectively analyzed. Compared with non-elderly adults, elderly individuals had significantly lower incidences of fever (P = 0.002), abdominal pain (P = 0.003), bone pain (P < 0.001), and skin rashes (P = 0.002); higher frequencies of concurrent bacteremia (P = 0.049), gastrointestinal bleeding (P = 0.044), acute renal failure (P = 0.001), and pleural effusion (P < 0.010); higher incidence of prolonged prothrombin time (P = 0.025); lower mean hemoglobin level (P < 0.001); longer hospitalization (P = 0.049); and a higher fatality rate (P = 0.006). Five elderly patients with DHF died. When compared with non-fatal elderly patients with DHF, a significant higher frequency in men (P = 0.019), those with chronic obstructive pulmonary disease (P = 0.008), those with dengue shock syndrome (DSS; P < 0.001), and those with acute renal failure (P < 0.001) was found in the elderly counterparts that died. Multivariate analysis showed that only DSS (odd ratio = 77.33, P = 0.001) was an independent risk factor for fatality in elderly patients.
TL;DR: The data support that HEV infection should be treated as a vocational illness in swine workers and systematic application of hygiene measures in this collective is highly recommended to avoid the exposition to this virus.
Abstract: The aim of this work was to study the prevalence of hepatitis E virus (HEV) and the risk factors for the acquisition of the virus in a population in contact with swine and unexposed to swine. A total of 198 individuals, 97 unexposed (49%) and 101 exposed (51%) to swine, were tested for the presence of HEV infection. The prevalence of anti-HEV IgG in the exposed group was 18.8% versus 4.1% in the unexposed to swine group. People exposed to swine were observed to be 5.4 times (P = 0.03) at risk of having anti-HEV IgG. Ten (52.6%) of the IgG-positive individuals showed two concomitant risk factors: untreated water consumption and exposure to swine. These data support that HEV infection should be treated as a vocational illness in swine workers. Therefore, systematic application of hygiene measures in this collective is highly recommended to avoid the exposition to this virus.
TL;DR: This vaccine candidate, therefore, warrants continued development in this age group (NCT00322049; clinicaltrials.gov), and was well-tolerated without any related SAEs.
Abstract: A Phase I/II observer-blind, randomized, controlled trial evaluated the safety and immunogenicity of a dengue virus (DENV) vaccine candidate in healthy Thai infants (aged 12-15 months) without measurable pre-vaccination neutralizing antibodies to DENV and Japanese encephalitis virus. Fifty-one subjects received two doses of either DENV (N = 34; four received 1/10th dose) or control vaccine (N = 17; dose 1, live varicella; dose 2, Haemophilus influenzae type b). After each vaccine dose, adverse events (AEs) were solicited for 21 days, and non-serious AEs were solicited for 30 days; serious AEs (SAEs) were recorded throughout the study. Laboratory safety assessments were performed at 10 and 30 days; neutralizing antibodies were measured at 30 days. The DENV vaccine was well-tolerated without any related SAEs. After the second dose, 85.7% of full-dose DENV vaccinees developed at least trivalent and 53.6% developed tetravalent neutralizing antibodies ≥ 1:10 to DENV (control group = 0%). This vaccine candidate, therefore, warrants continued development in this age group (NCT00322049; clinicaltrials.gov).
TL;DR: Collection of DENV-infected females from homes of dengue patients up to 27 days after the onset of symptoms shows the usefulness of indoor insecticide application in homes of suspected d Dengue patients to prevent their homes from becoming sources for dispersal ofDENV by persons visiting and being bitten by infected mosquitoes.
Abstract: We determined abundance of Aedes aegypti mosquitoes and presence of dengue virus (DENV) in females collected from premises of laboratory-confirmed dengue patients over a 12-month period (March 2007 to February 2008) in Merida, Mexico. Backpack aspiration from 880 premises produced 1,836 females and 1,292 males indoors (predominantly from bedrooms) and 102 females and 108 males from patios/backyards. The mean weekly indoor catch rate per home peaked at 7.8 females in late August. Outdoor abundances of larvae or pupae were not predictive of female abundance inside the home. DENV-infected Ae. aegypti females were recovered from 34 premises. Collection of DENV-infected females from homes of dengue patients up to 27 days after the onset of symptoms (median, 14 days) shows the usefulness of indoor insecticide application in homes of suspected dengue patients to prevent their homes from becoming sources for dispersal of DENV by persons visiting and being bitten by infected mosquitoes.
TL;DR: The six-dose regimen of artemether-lumefantrine was effective and well tolerated in the treatment of acute uncomplicated falciparum malaria in nonimmune patients and there were few serious adverse events.
Abstract: The efficacy and safety of artemether-lumefantrine for the treatment of malaria in nonimmune populations are not well defined. In this study, 165 nonimmune patients from Europe and non-malarious areas of Colombia with acute, uncomplicated falciparum malaria or mixed infection including P. falciparum were treated with the six-dose regimen of artemether-lumefantrine. The parasitologic cure rate at 28 days was 96.0% for the per protocol population (119/124 patients). Median times to parasite clearance and fever clearance were 41.5 and 36.8 hours, respectively. No patient had gametocytes after Day 7. Treatment was well tolerated; most adverse events were mild to moderate and seemed to be related to malaria. There were few serious adverse events, none of which were considered to be drug-related. No significant effects on ECG or laboratory parameters were observed. In conclusion, the six-dose regimen of artemether-lumefantrine was effective and well tolerated in the treatment of acute uncomplicated falciparum malaria in nonimmune patients.
TL;DR: Significant spatial clustering of malaria was observed in the areas of most recent occupation, indicating that the continuous influx of nonimmune settlers to forest-fringe areas perpetuates the cycle of environmental change and colonization that favors malaria transmission in rural Amazonia.
Abstract: Little follow-up data on malaria transmission in communities originating from frontier settlements in Amazonia are available. Here we describe a cohort study in a frontier settlement in Acre, Brazil, where 509 subjects contributed 489.7 person-years of follow-up. The association between malaria morbidity during the follow-up and individual, household, and spatial covariates was explored with mixed-effects logistic regression models and spatial analysis. Incidence rates for Plasmodium vivax and Plasmodium falciparum malaria were 30.0/100 and 16.3/100 person-years at risk, respectively. Malaria morbidity was strongly associated with land clearing and farming, and decreased after five years of residence in the area, suggesting that clinical immunity develops among subjects exposed to low malaria endemicity. Significant spatial clustering of malaria was observed in the areas of most recent occupation, indicating that the continuous influx of nonimmune settlers to forest-fringe areas perpetuates the cycle of environmental change and colonization that favors malaria transmission in rural Amazonia.
TL;DR: Despite shortcomings, boiling is the most common means of treating water at home and the benchmark against which emerging point-of-use water treatment approaches are measured, and it was associated with a 99% reduction in geometric mean fecal coliforms.
Abstract: Despite shortcomings, boiling is the most common means of treating water at home and the benchmark against which emerging point-of-use water treatment approaches are measured. In a 5-month study, we assessed the microbiological effectiveness and cost of the practice among 218 self-reported boilers relying on unprotected water supplies. Boiling was associated with a 99% reduction in geometric mean fecal coliforms (FCs; P < 0.001). Despite high levels of fecal contamination in source water, 59.6% of stored drinking water samples from self-reported boilers met the World Health Organization standard for safe drinking water (0 FC/100mL), and 5.7% were between 1 and 10 FC/100 mL. Nevertheless, 40.4% of stored drinking water samples were positive for FCs, with 25.1% exceeding 100 FC/100 mL. The estimated monthly fuel cost for boiling was INR 43.8 (US$0.88) for households using liquid petroleum gas and INR 34.7 (US$0.69) for households using wood.
TL;DR: T. cruzi infection in wild and domestic mammals from three orally acquired Chagas disease outbreak areas in Brazil shows a panzootic scenery, and domestic animals showed a high seroprevalence and should be considered sentinels in surveillance programs.
Abstract: We report Trypanosoma cruzi infection in wild and domestic mammals from three orally acquired Chagas disease outbreak areas in Brazil. Cachoeiro do Arari (Para) displayed a panzootic scenery (positive mammals in all ecologic strata), and human cases were probably the consequence of their exposure within the sylvatic T. cruzi transmission cycle. In Navegantes (Santa Catarina), Didelphis spp. was the main reservoir host, given that 93% were infected. In Redencao (Ceara), Monodelphis domestica and Thrichomys laurentius were also important for parasite maintenance. TCI was present in the three studied areas. Additionally, Z3 was detected in an armadillo from Para and TCII in a triatomine from Navegantes. Domestic animals showed a high seroprevalence and should be considered sentinels in surveillance programs. The importance of a reduction in wild mammalian fauna diversity and selection of suitable T. cruzi reservoir hosts are discussed as risk factors for the re-emergence of Chagas disease.