Biomedical subjects

Caryn Bern

Publications and source records attributed to Caryn Bern.

At least 19 recordsLinked to original sources

PubMed2006

Leishmaniasis and poverty.

Leishmaniasis, a neglected tropical disease, has strong but complex links with poverty. The burden of leishmaniasis falls disproportionately on the poorest segments of the global population. Within endemic areas, increased infection risk is mediated through poor housing conditions and environmental sanitation, lack of personal protective measures and economically driven migration and employment that bring nonimmune hosts into contact with infected sand flies. Poverty is associated with poor nutrition and other infectious diseases, which increase the risk that a person (once infected) will progress to the clinically manifested disease. Lack of healthcare access causes delays in appropriate diagnosis and treatment and accentuates leishmaniasis morbidity and mortality, particularly in women. Leishmaniasis diagnosis and treatment are expensive and families must sell assets and take loans to pay for care, leading to further impoverishment and reinforcement of the vicious cycle of disease and poverty. Public investment in treatment and control would decrease the leishmaniasis disease burden and help to alleviate poverty.

Animals↗

PubMed2006

Liposomal amphotericin B for the treatment of visceral leishmaniasis.

During the past decade, liposomal amphotericin B has been used with increasing frequency to treat visceral leishmaniasis (VL). The World Health Organization convened a workshop to review current knowledge and to develop guidelines for liposomal amphotericin B use for VL. In Europe, liposomal amphotericin B is widely used to treat VL. In Africa and Asia, the VL disease burden is high and drug access is poor; liposomal amphotericin B is available only through preferential pricing for nonprofit groups in East Africa. Clinical trials and experience demonstrate high efficacy and low toxicity for liposomal amphotericin B (total dose, 20 mg/kg) in immunocompetent patients with VL. Combination trials in areas with antileishmanial drug resistance, and treatment and secondary prophylaxis trials in VL-human immunodeficiency virus-coinfected patients, are important to safeguard the current armamentarium and to optimize regimens. The public health community should work to broaden access to preferential liposomal amphotericin B pricing by public sector VL treatment programs.

AIDS-Related Opportunistic Infections↗

PubMed2006

Multiplex analysis of circulating cytokines in the sera of patients with different clinical forms of visceral leishmaniasis.

BACKGROUND: The clinical spectrum of visceral leishmaniasis (VL), a chronic intracellular parasitic disease, ranges from a subclinical, asymptomatic infection to severe clinical disease (kala-azar). In experimental leishmaniasis, mice that have a Th1 response to infection tend to have limited disease while a Th2 response is associated with disease progression. Humans with VL most often have mixed rather than polarized responses. However, most clinical studies have used methods that require a relatively large sample volume, thus limiting their scope. Measuring multiple cytokine levels in blood samples using a multiplexed microsphere assay (MMA) may be useful to further evaluate the Th1/Th2 paradigm in humans. METHODS: Bangladeshi individuals (n=120) living in an area endemic for VL were categorized into one of the five clinical categories. Sera from these individuals were measured for levels of IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IFN-gamma, and TNF-alpha by multiplexed microsphere cytokine immunoassay. RESULTS: Circulating IL-8, IL-10, and IL-12 differed significantly among the clinical groups. Persons with kala-azar demonstrated the highest median levels of IL-8 and IL-10 but lower median levels of IL-12. CONCLUSIONS: The MMA for cytokines is an extremely time-and sample-efficient method for characterizing circulating cytokine levels in visceral leishmaniasis patients.

Adult↗

PubMed2006

The economic impact of visceral leishmaniasis on households in Bangladesh.

OBJECTIVES: To explore current patterns of diagnosis and treatment, quantify household economic impact and identify household strategies to cover the costs of visceral leishmaniasis (VL) care in rural Bangladesh. METHOD: Structured interviews with 113 VL patients from 87 households documenting all provider visits and expenditures for health care for VL, and the ways in which the expenditures were covered. RESULTS: Patients paid a median of 7 visits to six different providers before beginning VL treatment. All visited the subdistrict government hospital at least once. While health care, including antileishmanial drug therapy, is officially available free of charge at government facilities, 79% of patients reported making informal payments for provider access, diagnostics and drug administration; only 14% of patients received their full drug course from this source. For the 58% of patients who purchased the full treatment course, drug cost constituted 34% of direct expenditure. Median direct expenditure for one VL patient was US$87 and median income lost was $40; median total expenditure was 1.2 times annual per capita income of our study population. Households employed multiple coping strategies to cover expenditures, most commonly sale or rental of assets (62%) and taking out loans (64%). CONCLUSIONS: Visceral leishmaniasis treatment causes a major economic burden in affected families. Control strategies for VL should facilitate timely, affordable diagnosis and treatment of patients to decrease the infection reservoir and to alleviate the economic burden of VL on households.

Adaptation, Psychological↗

PubMed2006

Longitudinal analysis of cryptosporidium species-specific immunoglobulin G antibody responses in Peruvian children.

Cryptosporidium species are ubiquitous in the environment and are frequently detected in the stools of children who live where sanitation conditions are poor. To better characterize the immune response to these parasites, we monitored immunoglobulin G (IgG) antibody levels in a cohort of children from Lima, Peru. Two new enzyme-linked immunosorbent assays based on the C. parvum (bovine, subtype IIa) Iowa strain 17-kDa and 27-kDa antigens were used to measure IgG antibody levels in longitudinal serum samples. Antibody responses were detected during infections with C. parvum, C. felis, and C. meleagridis and with four different subtypes of C. hominis. We also noted that the magnitude of the antibody response was related to the number of previous infections and that older children generally had higher levels of antibodies to the two C. parvum antigens. Antibody responses were not associated with infections with either Cyclospora sp. or Giardia sp. We believe the antibody assays will be important tools for monitoring the success of future public health interventions.

Age Factors↗

PubMed2006

Mixed Cryptosporidium infections and HIV.

Mixed Cryptosporidium infections were detected in 7 of 21 patients with a diagnosis of rare Cryptosporidium canis or C. felis infections; 6 patients were infected with 2 Cryptosporidium spp. and 1 patient with 3 species. Mixed infections may occur more frequently than previously believed and should be considered when assessing cryptosporidiosis.

Animals↗

PubMed2006

Periurban Trypanosoma cruzi-infected Triatoma infestans, Arequipa, Peru.

In Arequipa, Peru, vectorborne transmission of Chagas disease by Triatoma infestans has become an urban problem. We conducted an entomologic survey in a periurban community of Arequipa to identify risk factors for triatomine infestation and determinants of vector population densities. Of 374 households surveyed, triatomines were collected from 194 (52%), and Trypanosoma cruzi-carrying triatomines were collected from 72 (19.3%). Guinea pig pens were more likely than other animal enclosures to be infested and harbored 2.38x as many triatomines. Stacked brick and adobe enclosures were more likely to have triatomines, while wire mesh enclosures were protected against infestation. In human dwellings, only fully stuccoed rooms were protected against infestation. Spatially, households with triatomines were scattered, while households with T. cruzi-infected triatomines were clustered. Keeping small animals in wire mesh cages could facilitate control of T. infestans in this densely populated urban environment.

Animals↗

PubMed2006

Seroepidemiology of strongyloidiasis in the Peruvian Amazon.

A stool and serosurvey for Strongyloides stercoralis was conducted in a community in the Peruvian Amazon region. Strongyloidiasis stercoralis was identified in the stool of 69 (8.7%) of 792 participants. Six hundred nine sera were tested using by an enzyme-linked immunosorbent assay (ELISA), which had a sensitivity of 92% and a specificity of 94%; 442 (72%) were positive. In multivariable logistic regression models, having S. stercoralis in stool was associated with hookworm in the same specimen (odds ratio [OR] = 4.44, 95% confidence interval [CI] = 2.02-9.79), occasionally or never wearing shoes (OR = 1.89, 95% CI = 1.10-3.27), and increasing age (OR = 1.012 for each one-year increase, 95% CI = 1.00-1.03). Similarly, occasionally or never wearing shoes (OR = 1.54, 95% CI = 1.01-2.37) and increasing age (OR = 1.04 for each one-year increase, 95% CI = 1.02-1.06) were associated with an increased risk of a positive S. stercoralis ELISA result. The ELISA had a negative predictive value of 98% and is an excellent screening test for strongyloidiasis.

Adolescent↗

PubMed2006

The epidemiology of visceral leishmaniasis in Bangladesh: prospects for improved control.

The parasitic disease kala-azar (visceral leishmaniasis, VL) was first described in 1824 in Jessore district, Bengal (now Bangladesh). Epidemic peaks were recorded in Bengal in the 1820s, 1860s, 1920s, and 1940s. After achieving good control of the disease during the intensive vector control efforts for malaria in the 1950s-1960s, Bangladesh experienced a VL resurgence that has lasted to the present. Surveillance data show an increasing trend in incidence since 1995. Research in recent years has demonstrated the utility of non-invasive diagnostic modalities such as the direct agglutination test and rapid tests based on the immune response to the rK39 antigen. In common with its neighbours India and Nepal, VL in Bangladesh is anthroponotic. Living in proximity to a kala-azar case is the strongest risk factor for disease, while consistent use of bed nets in the summer months and the presence of cattle are protective. Shortages of first-line antileishmanial drugs and insecticide for indoor spraying programmes have hindered VL treatment and vector control efforts. Effective control of VL will require activities to improve availability and access to diagnostic testing and antileishmanial drugs, enhanced surveillance for kala-azar, post-kala-azar dermal leishmaniasis and VL treatment failures, and increased coverage and efficacy of vector control programmes.

Bangladesh↗

PubMed2006

Loss of leishmanin skin test antigen sensitivity and potency in a longitudinal study of visceral leishmaniasis in Bangladesh.

Annual leishmanin skin test (LST) surveys were conducted in a visceral leishmaniasis-endemic Bangladeshi community from 2002 through 2004, using Leishmania infantum antigen from the same manufacturer and batch. In 2002, 530 (35%) of 1,532 had positive LST results; the prevalence increased with increasing age. The LST result was positive in 24 (51%) of 47, 18 (72%) of 25, and 11 (85%) of 13 kala-azar patients treated in the previous 1-11, 12-23, and 24-35 months. A positive LST result in 2002 was associated with protection against subsequent kala-azar (P < 0.0001). In 2003-2004, decreased antigen sensitivity was observed. Among 686 participants, 34% were LST-positive in 2002, 29% in 2003, and 19% in 2004. Of 63 cured kala-azar patients, 70% were positive in 2002, 53% in 2003, and only 30% in 2004. Among 171 participants tested with both antigens, L. infantum study antigen sensitivity was 70% compared with L. amazonensis antigen. Our data underscore the need for better production, standardization, and documentation of sensitivity, potency, and stability of leishmanin antigens.

Adolescent↗

PubMed2005

The epidemiology of intestinal microsporidiosis in patients with HIV/AIDS in Lima, Peru.

We studied microsporidiosis in human immunodeficiency virus-positive patients in 2 Lima hospitals. Of 2652 patients, 66% were male, 6% received antiretroviral therapy (ART), and the median CD4 lymphocyte count was 131 cells/microL. Sixty-seven patients (3%) had microsporidiosis; stool specimens from 56 were identified as having Enterocytozoon bieneusi of 10 different genotypes. The 2 most common genotypes, Peru-1 and Peru-2, were not associated with significant increases in chronic diarrhea; other genotypes were associated with a 4-fold increased risk. Risk factors for E. bieneusi infection segregated by genotype: contact with duck or chicken droppings and lack of running water, flush toilet, or garbage collection with genotype Peru-1 and watermelon consumption with other genotypes. Shortened survival was associated with low CD4 lymphocyte count (P<.0001), no ART (P<.0001), and cryptosporidiosis (P=.004) but not with microsporidiosis (P=.48). Our data suggest the possibility of zoonotic E. bieneusi transmission and an association with poor sanitary conditions.

AIDS-Related Opportunistic Infections↗

PubMed2005

Changes in serum immunoglobulin G levels as a marker for Cryptosporidium sp. infection in Peruvian children.

In a retrospective analysis, we assessed the usefulness of two serologic enzyme-linked immunosorbent assays as epidemiologic tools for the detection of cryptosporidiosis episodes in children from a Peruvian community. The incidence rate determined by the serologic assay was higher than the rate determined by stool microscopy (0.77 versus 0.41 infection/child-year of surveillance).

Animals↗

PubMed2005

Risk factors for kala-azar in Bangladesh.

Since 1990, South Asia has experienced a resurgence of kala-azar (visceral leishmaniasis). To determine risk factors for kala-azar, we performed cross-sectional surveys over a 3-year period in a Bangladeshi community. By history, active case detection, and serologic screening, 155 of 2,356 residents had kala-azar with onset from 2000 to 2003. Risk was highest for persons 3-45 years of age, and no significant difference by sex was seen. In age-adjusted multivariable models, 3 factors were identified: proximity to a previous kala-azar patient (odds ratio [OR] 25.4, 95% confidence interval [CI] 15-44 within household; OR 3.2 95% CI 1.7-6.1 within 50 m), bed net use in summer (OR 0.7, 95% CI 0.53-0.93), and cattle per 1,000 m2 (OR 0.8, 95% CI 0.70-0.94]). No difference was seen by income, education, or occupation; land ownership or other assets; housing materials and condition; or keeping goats or chickens inside bedrooms. Our data confirm strong clustering and suggest that insecticide-treated nets could be effective in preventing kala-azar.

Adolescent↗

PubMed2005

Virgin soil: the spread of visceral leishmaniasis into Uttar Pradesh, India.

We conducted a cross-sectional study to determine the incidence of visceral leishmaniasis (VL) and risk factors in two villages in Uttar Pradesh, India reported to have had a recent outbreak. In 245 households with 2,203 people, we detected 3 current VL cases, 32 past cases, and 8 VL deaths since 2001 (annual incidence = 6 per 1,000). Risk factors included living in the same household as a VL case (odds ratio [OR] = 76, P < 0.0005 in one village and OR = 22, P < 0.0005 in the other village), sleeping downstairs and outside in the summer (OR = 4.7, P = 0.004), and an age > or = 15 years old (OR = 2.9, P = 0.024). Increasing cattle density was a risk factor in one village but not the other. We were not able to determine the route by which VL entered the villages. Our data demonstrate a new spread of VL in previously unaffected areas. We recommend carefully supervised spraying with DDT, surveillance to pinpoint other affected villages, and efforts to increase availability of diagnostic and treatment facilities.

Adolescent↗

PubMed2004

Visceral leishmaniasis: consequences to women in a Bangladeshi community.

Visceral leishmaniasis (VL) or kala-azar (KA) affects the rural poor, causing significant morbidity and mortality. We examined the epidemiological and social impact of KA in an affected village in Bangladesh. A population-based survey of the village residents showed a case fatality rate of 14.7% among females and 5.3% among males. Before initiation of the study, female patients were ill longer than males before they received treatment. Future work needs to focus on understanding the implications of KA on women and to develop sustainable strategies for appropriate and timely access to treatment.

Adolescent↗

PubMed2004

Purification of Enterocytozoon bieneusi spores from stool specimens by gradient and cell sorting techniques.

A three-step method for the purification of Enterocytozoon bieneusi spores from stool specimens was developed. The primary process of purification of the spores from bacterial contaminants involved Percoll gradient centrifugation followed by additional separation using cesium chloride density gradient centrifugation. The cesium chloride-isolated spores were further purified using a flow cytometer with cell sorting capabilities. Sorting was performed without the use of antibodies, fluorochromes, or dyes, leaving the sorted spores in their native state, which appears to be less destructive for spores. When quantified by flow cytometry using tubes with known numbers of highly fluorescent polystyrene beads, the sorted material showed a slight decrease in light scatter characteristics compared with the slightly larger Encephalitozoon species spores. Although the overall recovery of the E. bieneusi spores was low, calcofluor and Gram chromotrope staining, indirect immunofluorescence assay, and transmission electron microscopy revealed that the sorted material was highly purified and contained large numbers of E. bieneusi spores and relatively few bacteria and other debris. The sorted material appeared to be sufficiently pure and could be used for in vitro culture and for the development of a variety of diagnostic reagents as well as in studying the genome of E. bieneusi and host-parasite interactions.

Cell Separation↗

PubMed2004

Prevalence of infection with waterborne pathogens: a seroepidemiologic study in children 6-36 months old in San Juan Sacatepequez, Guatemala.

Water and sanitation interventions in developing countries have historically been difficult to evaluate. We conducted a seroepidemiologic study with the following goals: 1) to determine the feasibility of using antibody markers as indicators of waterborne pathogen infection in the evaluation of water and sanitation intervention projects; 2) to characterize the epidemiology of waterborne diarrheal infections in rural Guatemala, and 3) to measure the age-specific prevalence of antibodies to waterborne pathogens. Between September and December 1999, all children 6-36 months of age in 10 study villages were invited to participate. We collected sufficient serum from 522 of 590 eligible children, and divided them into six-month age groups for analysis (6-12, 13-18, 19-24, 25-30, and 31-36 months). The prevalence of antibodies was lowest in children 6-12 months old compared with the four older age groups for the following pathogens: enterotoxigenic Escherichia coli (48%, 81%, 80%, 77%, and 83%), Norwalk virus (27%, 61%, 83%, 94%, and 94%), and Cryptosporidium parvum (27%, 53%, 70%, 67%, and 73%). The prevalence of total antibody to hepatitis A virus increased steadily in the three oldest age groups (40%, 28%, 46%, 60%, and 76%). In contrast, the prevalence of antibody to Helicobacter pylori was relatively constant in all five age groups (20%, 19%, 21%, 25%, and 25%). Serology appears to be an efficient and feasible approach for determining the prevalence of infection with selected waterborne pathogens in very young children. Such an approach may provide a suitable, sensitive, and economical alternative to the cumbersome stool collection methods that have previously been used for evaluation of water and sanitation projects.

Animals↗

PubMed2003

The global burden of diarrhoeal disease, as estimated from studies published between 1992 and 2000.

Current estimates of the global burden of disease for diarrhoea are reported and compared with previous estimates made using data collected in 1954-79 and 1980-89. A structured literature review was used to identify studies that characterized morbidity rates by prospective surveillance of stable populations and studies that characterized mortality attributable to diarrhoea through active surveillance. For children under 5 years of age in developing areas and countries, there was a median of 3.2 episodes of diarrhoea per child-year. This indicated little change from previously described incidences. Estimates of mortality revealed that 4.9 children per 1000 per year in these areas and countries died as a result of diarrhoeal illness in the first 5 years of life, a decline from the previous estimates of 13.6 and 5.6 per 1000 per year. The decrease was most pronounced in children aged under 1 year. Despite improving trends in mortality rates, diarrhoea accounted for a median of 21% of all deaths of children aged under 5 years in these areas and countries, being responsible for 2.5 million deaths per year. There has not been a concurrent decrease in morbidity rates attributable to diarrhoea. As population growth is focused in the poorest areas, the total morbidity component of the disease burden is greater than previously.

Child, Preschool↗