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Biomedical subjects

Timothy H Holtz

Publications and source records attributed to Timothy H Holtz.

14 recordsLinked to original sources
PubMed2006

Spatial analysis and mapping of malaria risk in Malawi using point-referenced prevalence of infection data.

BACKGROUND: Current malaria control initiatives aim at reducing malaria burden by half by the year 2010. Effective control requires evidence-based utilisation of resources. Characterizing spatial patterns of risk, through maps, is an important tool to guide control programmes. To this end an analysis was carried out to predict and map malaria risk in Malawi using empirical data with the aim of identifying areas where greatest effort should be focussed. METHODS: Point-referenced prevalence of infection data for children aged 1-10 years were collected from published and grey literature and geo-referenced. The model-based geostatistical methods were applied to analyze and predict malaria risk in areas where data were not observed. Topographical and climatic covariates were added in the model for risk assessment and improved prediction. A Bayesian approach was used for model fitting and prediction. RESULTS: Bivariate models showed a significant association of malaria risk with elevation, annual maximum temperature, rainfall and potential evapotranspiration (PET). However in the prediction model, the spatial distribution of malaria risk was associated with elevation, and marginally with maximum temperature and PET. The resulting map broadly agreed with expert opinion about the variation of risk in the country, and further showed marked variation even at local level. High risk areas were in the low-lying lake shore regions, while low risk was along the highlands in the country. CONCLUSION: The map provided an initial description of the geographic variation of malaria risk in Malawi, and might help in the choice and design of interventions, which is crucial for reducing the burden of malaria in Malawi.

Cluster Analysis↗
PubMed2006

Time to sputum culture conversion in multidrug-resistant tuberculosis: predictors and relationship to treatment outcome.

BACKGROUND: Conversion of sputum mycobacterial cultures from positive growth to negative growth of Mycobacterium tuberculosis in patients with pulmonary tuberculosis (TB) is considered the most important interim indicator of the efficacy of anti-TB pharmacologic treatment for multidrug-resistant disease. OBJECTIVE: To evaluate and compare time to and predictors of initial sputum culture conversion with predictors of treatment outcome for patients with multidrug-resistant TB. DESIGN: Retrospective cohort study. SETTING: Latvia. PATIENTS: All civilian patients with multidrug-resistant TB treated with the DOTS-Plus strategy between 1 January and 31 December 2000. INTERVENTION: Individualized treatment for confirmed sputum culture-positive pulmonary multidrug-resistant TB. MEASUREMENTS: Time to initial sputum culture conversion and treatment outcome. RESULTS: Among 167 patients who were sputum culture-positive at initiation of second-line therapy, 129 (77%) converted in a median time of 60 days (range, 4 to 462 days) and 38 (23%) did not convert. Independent predictors of a longer sputum culture conversion time, using an accelerated failure time regression model, included previous treatment for multidrug-resistant TB, high initial sputum culture colony count, bilateral cavitations on chest radiography, and the number of drugs the initial isolate was resistant to at treatment initiation. Treatment outcomes were statistically significantly worse for patients who did not convert their sputum culture within 2 months. LIMITATIONS: Twenty-five percent of patients missed 5 or more monthly sputum collections. CONCLUSIONS: Under program conditions in Latvia, most patients with multidrug-resistant TB achieved sputum culture conversion within 12 weeks of starting treatment. Chest radiography and sputum culture drug susceptibility testing can assist physicians in predicting which patients will convert more slowly. Sputum culture conversion is a useful and appropriate interim indicator of treatment outcome in patients with multidrug-resistant TB.

Adolescent↗
PubMed2005

Prevalence of mental disorders and torture among Tibetan refugees: a systematic review.

BACKGROUND: Many Tibetan refugees flee Tibet in order to escape physical and mental hardships, and to access the freedoms to practice their culture and religion. We aimed to determine the prevalence of mental illnesses within the refugee population and determine the prevalence of previous torture reported within this population. METHODS: We performed a systematic literature search of 10 electronic databases from inception to May 2005. In addition, we searched the internet, contacted all authors of located studies, and contacted the Tibetan Government-in-exile, to locate unpublished studies. We included any study reporting on prevalence of mental illness within the Tibetan refugee populations. We determined study quality according to validation, translation, and interview administration. We calculated proportions with exact confidence intervals. RESULTS: Five studies that met our inclusion criteria (total n = 410). All studies were conducted in North India and 4 were specifically in adult populations. Four studies provided details on the prevalence of torture and previous imprisonment within the populations. The prevalence of post-traumatic stress disorder ranged from 11-23%, anxiety ranged from 25-77%, and major depression ranged from 11.5-57%. CONCLUSION: Our review indicates that the prevalence of serious mental health disorders within this population is elevated. The reported incidence of torture and imprisonment is a possible contributor to the illnesses. Non-government organizations and international communities should be aware of the human rights abuses being levied upon this vulnerable population and the mental health outcomes that may be associated with it.

Journal Article↗
PubMed2005

The mental health of expatriate and Kosovar Albanian humanitarian aid workers.

The mental health consequences of exposure to traumatic events and the risk factors for psychological morbidity among expatriate and Kosovar Albanian humanitarian aid workers have not been well studied. In June 2000, we used standardised screening tools to survey 285 (69.5%) of 410 expatriate aid workers and 325 (75.8%) of 429 Kosovar Albanian aid workers from 22 humanitarian organizations that were implementing health programmes in Kosovo. The mean number of trauma events experienced by expatriates was 2.8 (standard deviation: 2.7) and by Kosovar staff 3.2 (standard deviation: 2.8). Although only 1.1% of expatriate and 6.2% of Kosovar aid workers reported symptoms consistent with the diagnosis for post-traumatic stress disorder, 17.2% and 16.9%, respectively, reported symptoms satisfying the definition of depression. Regression analysis demonstrated that the number of trauma events experienced was significantly associated with depression for the two sets of workers. Organisational support services may be an important mediating factor and should be targeted at both groups.

Adolescent↗
PubMed2005

Relationship of measles vaccination with anaemia and malaria in western Kenya.

OBJECTIVE: Mild viral illness, including that following immunization with live attenuated measles virus (LAMV), has been associated with transient decreases in haemoglobin (Hb) and cellular immune response that may persist for several weeks. In areas of intense malaria transmission, such as western Kenya, infants experience a progressive drop in Hb until age 9-10 months and one-third may have Hb < 8 g/dl. These children may be at risk of developing severe anaemia with further haematological insult. The objective of this paper was to determine if immunization with LAMV was associated with increased risk of transient anaemia and malaria infection. METHODS: Data from previous cross-sectional surveys (n = 5970) and one cohort study (n = 546) conducted among pre-school children were analyzed retrospectively. RESULTS: Measles vaccination coverage between 12 and 23 months of age ranged from 44.8% to 62.7%. Hb concentrations in children aged 6-23 months with documented measles immunization within the previous 14 or 30 days (n = 103) were similar to those with no history of measles immunization in the previous 90 days (n = 996); mean differences [95% confidence interval (CI)] by 30 days were: in cross-sectional surveys, -0.49 g/dl (-1.12, 0.14); in the cohort study, -0.032 g/dl (-0.52, 0.46). Similarly, the risk of malaria parasitemia or severe to moderate anaemia did not differ. CONCLUSION: These data do not suggest that the transient decrease in Hb and cellular immune response after immunization with LAMV results in clinically significant changes in the risk of subsequent severe to moderate anaemia or malaria in young children living in malaria-endemic regions.

Anemia↗
PubMed2005

Multidrug-resistant tuberculosis detection, Latvia.

To improve multidrug-resistant tuberculosis (MDR-TB) detection, we successfully introduced the rpoB gene mutation line probe assay into the national laboratory in Latvia, a country with epidemic MDR-TB. The assay detected rifampin resistance with 91% sensitivity and 96% specificity within 1 to 5 days (vs. 12-47 days for BACTEC).

Antitubercular Agents↗
PubMed2004

Use of antenatal care services and intermittent preventive treatment for malaria among pregnant women in Blantyre District, Malawi.

Malaria in pregnancy contributes to low birth weight and increased infant mortality. As part of WHO's Roll Back Malaria initiative, African heads of state pledged that by 2005, 60% of pregnant women will receive malaria chemoprophylaxis or intermittent preventive treatment (IPT). We performed a cluster sample survey to study the use of sulfadoxine-pyrimethamine (SP) for IPT among recently pregnant women in February 2000 in Blantyre District, Malawi. Among 391 women in the sample, 98.6% had attended antenatal clinic at least once and 90.2% knew that SP/IPT was recommended during pregnancy. Overall, only 36.8% received the full recommended two-dose regimen of SP/IPT. Using data from 187 women with antenatal clinic cards, we found that residence location, housing type and gender/age/education of the head of household were not associated with failure to receive SP/IPT. Adjusting for education, multigravid women were more likely not to receive the recommended SP/IPT regimen (RR 1.2, 95% CI 1.02-1.5, P=0.03). A substantial effort to improve the delivery and use of SP/IPT in Malawi will be necessary, but the Roll Back Malaria 2005 goal appears achievable.

Adolescent↗
PubMed2003

Isolated case of bioterrorism-related inhalational anthrax, New York City, 2001.

On October 31, 2001, in New York City, a 61-year-old female hospital employee who had acquired inhalational anthrax died after a 6-day illness. To determine sources of exposure and identify additional persons at risk, the New York City Department of Health, Centers for Disease Control and Prevention, and law enforcement authorities conducted an extensive investigation, which included interviewing contacts, examining personal effects, summarizing patient's use of mass transit, conducting active case finding and surveillance near her residence and at her workplace, and collecting samples from co-workers and the environment. We cultured all specimens for Bacillus anthracis. We found no additional cases of cutaneous or inhalational anthrax. The route of exposure remains unknown. All environmental samples were negative for B. anthracis. This first case of inhalational anthrax during the 2001 outbreak with no apparent direct link to contaminated mail emphasizes the need for close coordination between public health and law enforcement agencies during bioterrorism-related investigations.

Anthrax↗
PubMed2002

An outbreak of eosinophilic meningitis caused by Angiostrongylus cantonensis in travelers returning from the Caribbean.

BACKGROUND: Outbreaks of eosinophilic meningitis caused by the roundworm Angiostrongylus cantonensis are rarely reported, even in regions of endemic infection such as Southeast Asia and the Pacific Basin. We report an outbreak of A. cantonensis meningitis among travelers returning from the Caribbean. METHODS: We conducted a retrospective cohort study among 23 young adults who had traveled to Jamaica. We used a clinical definition of eosinophilic meningitis that included headache that began within 35 days after the trip plus at least one of the following: neck pain, nuchal rigidity, altered cutaneous sensations, photophobia, or visual disturbances. RESULTS: Twelve travelers met the case definition for eosinophilic meningitis. The symptoms began a median of 11 days (range, 6 to 31) after their return to the United States. Eosinophilia was eventually documented in all nine patients who were hospitalized, although on initial evaluation, it was present in the peripheral blood of only four of the nine (44 percent) and in the cerebrospinal fluid of five (56 percent). Repeated lumbar punctures and corticosteroid therapy led to improvement in symptoms in two of three patients with severe headache, and intracranial pressure decreased during corticosteroid therapy in all three. Consumption of one meal (P=0.001) and of a Caesar salad at that meal (P=0.007) were strongly associated with eosinophilic meningitis. Antibodies against an A. cantonensis--specific 31-kD antigen were detected in convalescent-phase serum samples from 11 patients. CONCLUSIONS: Among travelers at risk, the presence of headache, elevated intracranial pressure, and pleocytosis, with or without eosinophilia, particularly in association with paresthesias or hyperesthesias, should alert clinicians to the possibility of A. cantonensis infection.

Adrenal Cortex Hormones↗
PubMed2002

Mental health status of human rights workers, Kosovo, June 2000.

Human rights workers in humanitarian relief settings may be exposed to traumatic events that put them at risk for psychiatric morbidity. We conducted a cross-sectional survey in June 2000 to study the prevalence of psychiatric morbidity among 70 expatriate and Kosovar Albanian staff collecting human nights data in Kosovo. Among those surveyed, elevated levels of anxiety, depression, and posttraumatic stress disorder symptoms were found in 17.1, 8.6, and 7.1% respectively. Multiple regression analysis revealed that human rights workers at risk for elevated anxiety symptoms were those who had worked with their organization longer than 6 months, those who had experienced an armed attack, and those who experienced local hostility. Our study indicates that human rights organizations should consider mental health assessment, care, and prevention programs for their staff.

Adolescent↗
PubMed2002

Insecticide-treated bednet use, anaemia, and malaria parasitaemia in Blantyre District, Malawi.

OBJECTIVE: To evaluate the use of insecticide-treated bednets and the effectiveness of social marketing for their distribution. METHODS: Systematic cluster sample survey of 1080 households in 36 census enumeration areas across Blantyre district, Malawi, in February 2000. RESULTS: A total of 672 households had one or more children under 5. Bednet ownership was low (20.5% of households) overall, and significantly lower in rural areas than urban areas (6.4 vs. 29.8%, P=0.001). Only 3.3% of rural children under 5 had slept under a net the previous night, compared with 24.0% of urban children (P < 0.001). When asked why they did not own a net, nearly all (94.9%) caretakers in households without nets stated they had no money to buy them. In multivariate statistical models that controlled for the influence of house structure, urban vs. rural location, gender of the head of household, and the primary caretaker's education, rural children under 5 in households without nets experienced a statistically significant higher prevalence of malaria parasitaemia [RR (risk ratio) 4.9, 95% CI (confidence interval) 2.3-10.5] than children in households with at least one bednet. This was also true for urban children under 5 (RR 2.1, 95% CI 1.0-4.2, P=0.04). CONCLUSION: Social marketing approaches to promoting insecticide-treated nets in Blantyre District may have produced measurable health benefits for children in those households in which residents bought and used the products. Market-based approaches may take years to achieve high levels of coverage and may exaggerate inequities between urban and rural populations.

Adolescent↗
PubMedDate not supplied

Care seeking behaviour and treatment of febrile illness in children aged less than five years: a household survey in Blantyre District, Malawi.

Malaria is a leading cause of death in children aged < 5 years in Malawi. As part of the Roll Back Malaria initiative, African heads of state have pledged that by 2005, 60% of children will receive an effective antimalarial drug within 24 h of developing fever. In 1993, Malawi switched from chloroquine to sulfadoxine-pyrimethamine (SP) in its recommendations of home treatment of febrile illness in children. To study care seeking behaviour and home treatment in Blantyre District, and provide valuable follow-up to the chloroquine to SP transition, we performed a 2-stage cluster-sample survey in February 2000. Our sample of 1080 households included 672 households with children aged < 5 years; 292 (32.2%, 95% CI 28.7-35.8%) of the 912 children in these households had completed a febrile episode within the past 14 d. Among recently febrile children, 210 (72.0%, 95% CI 67.0-77.1%) received medication at home during their illness, but only 36 (12.2%, 95% CI 8.4-16.0%) received an appropriate antimalarial drug. Overall, 111 (37.4%, 95% CI 30.9-43.9%) received prompt, appropriate treatment. Only rural location was statistically associated with failure to receive prompt appropriate treatment (risk ratio estimate 1.2, 95% CI 1.01-1.5). A greater effort to improve the quality of malaria home treatment or to expand health facility utilization will be necessary to achieve Roll Back Malaria goals before 2005 in Blantyre District. Current care seeking practices suggest interventions should stress promptness of health facility visits, improved access to appropriate drugs, and accurate dosing for home-based treatments.

Ambulatory Care↗
PubMedDate not supplied

Clinical outcome of individualised treatment of multidrug-resistant tuberculosis in Latvia: a retrospective cohort study.

BACKGROUND: Latvia has one of the highest rates of multidrug-resistant tuberculosis (MDRTB). Our aim was to assess treatment outcomes for the first full cohort of MDRTB patients treated under Latvia's DOTS-Plus strategy following WHO guidelines. METHODS: We retrospectively reviewed all civilian patients who began treatment with individualised treatment regimens for pulmonary MDRTB in Latvia between Jan 1, and Dec 31, 2000. We applied treatment outcome definitions for MDRTB, developed by an international expert consensus group, and assessed treatment effectiveness and risk factors associated with poor outcome. FINDINGS: Of the 204 patients assessed, 55 (27%) had been newly diagnosed with MDRTB, and 149 (73%) had earlier been treated with first-line or second-line drugs for this disease. Assessment of treatment outcomes showed that 135 (66%) patients were cured or completed therapy, 14 (7%) died, 26 (13%) defaulted, and treatment failed in 29 (14%). Of the 178 adherent patients, 135 (76%) achieved cure or treatment completion. In a multivariate Cox proportional-hazards model of these patients, independent predictors of poor outcome (death and treatment failure) included having previously received treatment for MDRTB (hazard ratio 5.7, 95% CI 1.9-16.6), the use of five or fewer drugs for 3 months or more (3.2, 1.1-9.6), resistance to ofloxacin (2.6, 1.2-5.4), and body-mass index less than 18.5 at start of treatment (2.3, 1.1-4.9). INTERPRETATION: The DOTS-Plus strategy of identifying and treating patients with MDRTB can be effectively implemented on a nationwide scale in a setting of limited resources.

Adolescent↗