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711 results on '"Palmer, Guy H."'

1. Risk factors for colonization with extended-spectrum cephalosporin-resistant and carbapenem-resistant Enterobacterales among hospitalized patients in Guatemala: An Antibiotic Resistance in Communities and Hospitals (ARCH) study

Author

Caudell, Mark A., Castillo, Carmen, Santos, Lucas F., Grajeda, Laura, Romero, Juan Carlos, Lopez, Maria Renee, Omulo, Sylvia, Ning, Mariangeli Freitas, Palmer, Guy H., Call, Douglas R., Cordon-Rosales, Celia, Smith, Rachel M., Herzig, Carolyn T.A., Styczynski, Ashley, and Ramay, Brooke M.

Published
2024
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2. Prevalence of colonization with multidrug-resistant bacteria in communities and hospitals in Kenya

Author

Ita, Teresa, Luvsansharav, Ulzii-Orshikh, Smith, Rachel M., Mugoh, Robert, Ayodo, Charchil, Oduor, Beatrice, Jepleting, Moureen, Oguta, Walter, Ouma, Caroline, Juma, Jane, Bigogo, Godfrey, Kariuki, Samuel, Ramay, Brooke M., Caudell, Mark, Onyango, Clayton, Ndegwa, Linus, Verani, Jennifer R., Bollinger, Susan, Sharma, Aditya, Palmer, Guy H., Call, Douglas R., and Omulo, Sylvia

Published
2022
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3. An adjuvant formulation containing Toll-like Receptor 7 agonist stimulates protection against morbidity and mortality due to Anaplasma marginale in a highly endemic region of west Africa.

Author

Futse, James E., Zumor-Baligi, Songliedong, Ashiagbor, Charles N. K., Noh, Susan M., Fox, Christopher B., and Palmer, Guy H.

Subjects
TOLL-like receptor agonists, ANAPLASMA marginale, PROTOZOAN diseases, VACCINE effectiveness, BACTERIAL diseases
Abstract

Efficient cattle production and provision of animal-sourced foods in much of Africa is constrained by vector-borne bacterial and protozoal diseases. Effective vaccines are not currently available for most of these infections resulting in a continuous disease burden that limits genetic improvement. We tested whether stimulation of innate immunity using the Toll-like Receptor (TLR) 7 agonist imiquimod, formulated with saponin and water-in-oil emulsion, would protect against morbidity and mortality due to Anaplasma marginale, a tick-borne pathogen of cattle highly endemic in west Africa. In Trial 1, haplotype matched Friesian x Sanga (F1) A. marginale negative calves were allocated to either the experimental group (n = 10) and injected with the synthetic TLR 7 agonist/saponin formulation or to an untreated control group (n = 10). TLR7 agonist/saponin injected calves responded with significantly elevated rectal temperature, enlarged regional lymph nodes, and elevated levels of IL-6 post-injection as compared to control group calves. All calves were then allowed to graze in pasture for natural exposure to tick transmission. All calves in both groups acquired A. marginale, consistent with the high transmission rate in the endemic region. The need for antibiotic treatment, using pre-existing criteria, was significantly lower in the experimental group (odds ratio for not requiring treatment was 9.3, p = 0.03) as compared to the control group. Despite treatment, 6/10 calves in the control group died, reflecting treatment failures that are typical of anaplasmosis in the acute phase, while mortality in the experimental group was 1/10 (odds ratio for survival was 13.5, p = 0.03). The trial was then repeated using 45 Friesian x Sanga calves per group. In Trial 2, the odds ratios for preventing the need for treatment and for mortality in the TLR7 agonist/saponin experimental group versus the control group were 5.6 (p = 0.0002) and 7.0 (p = 0.004), respectively, reproducing the findings of the initial trial. Together these findings demonstrate that innate immune stimulation using a TLR7 agonist formulated with saponin and water-in-oil emulsion provides significant protection against disease caused by tick borne A. marginale in highly susceptible cross-bred cattle, critically important for their potential to increase productivity for smallholder farmers in Africa. [ABSTRACT FROM AUTHOR]

Published
2024
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4. Within Host Evolution Selects for a Dominant Genotype of Mycobacterium tuberculosis while T Cells Increase Pathogen Genetic Diversity.

Author

Copin, Richard, Wang, Xueying, Louie, Eddie, Escuyer, Vincent, Coscolla, Mireia, Gagneux, Sebastien, Palmer, Guy H, and Ernst, Joel D

Subjects
T-Lymphocytes, Animals, Mice, Inbred C57BL, Mice, Knockout, Humans, Mice, Mycobacterium tuberculosis, Tuberculosis, Evolution, Molecular, Genotype, Genetic Variation, Molecular Epidemiology, High-Throughput Nucleotide Sequencing, Inbred C57BL, Knockout, Evolution, Molecular, Virology, Microbiology, Immunology, Medical Microbiology
Abstract

Molecular epidemiological assessments, drug treatment optimization, and development of immunological interventions all depend on understanding pathogen adaptation and genetic variation, which differ for specific pathogens. Mycobacterium tuberculosis is an exceptionally successful human pathogen, yet beyond knowledge that this bacterium has low overall genomic variation but acquires drug resistance mutations, little is known of the factors that drive its population genomic characteristics. Here, we compared the genetic diversity of the bacteria that established infection to the bacterial populations obtained from infected tissues during murine M. tuberculosis pulmonary infection and human disseminated M. bovis BCG infection. We found that new mutations accumulate during in vitro culture, but that in vivo, purifying selection against new mutations dominates, indicating that M. tuberculosis follows a dominant lineage model of evolution. Comparing bacterial populations passaged in T cell-deficient and immunocompetent mice, we found that the presence of T cells is associated with an increase in the diversity of the M. tuberculosis genome. Together, our findings put M. tuberculosis genetic evolution in a new perspective and clarify the impact of T cells on sequence diversity of M. tuberculosis.

Published
2016

5. The Livestock for Health Study: A Field Trial on Livestock Interventions to Prevent Acute Malnutrition Among Women and Children in Pastoralist Communities in Northern Kenya

Author

Thumbi, Samuel M., primary, Muema, Josphat, additional, Mutono, Nyamai, additional, Njuguna, Joseph, additional, Jost, Christine, additional, Boyd, Erin, additional, Tewoldeberhan, Daniel, additional, Mutua, Immaculate, additional, Gacharamu, George, additional, Wambua, Francis, additional, Allport, Rob, additional, Olesambu, Emmanuella, additional, Osman, Abdal Monium, additional, Souza, Darana, additional, Kimani, Irene, additional, Oyugi, Julius, additional, Bukania, Zipporah, additional, Oboge, Harriet, additional, Palmer, Guy H., additional, and Yoder, Jonathan, additional

Published
2023
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9. Colonization With Antibiotic-Resistant Bacteria in a Hospital and Associated Communities in Guatemala: An Antibiotic Resistance in Communities and Hospitals (ARCH) Study

Author

Ramay, Brooke M, primary, Castillo, Carmen, additional, Grajeda, Laura, additional, Santos, Lucas F, additional, Romero, Juan Carlos, additional, Lopez, Maria Renee, additional, Gomez, Andrea, additional, Caudell, Mark, additional, Smith, Rachel M, additional, Styczynski, Ashley, additional, Herzig, Carolyn T A, additional, Bollinger, Susan, additional, Ning, Mariangeli Freitas, additional, Horton, Jennifer, additional, Omulo, Sylvia, additional, Palmer, Guy H, additional, Cordon-Rosales, Celia, additional, and Call, Douglas R, additional

Published
2023
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10. Risk Factors for Colonization With Multidrug-Resistant Bacteria in Urban and Rural Communities in Kenya: An Antimicrobial Resistance in Communities and Hospitals (ARCH) Study

Author

Caudell, Mark A, primary, Ayodo, Charchil, additional, Ita, Teresa, additional, Smith, Rachel M, additional, Luvsansharav, Ulzii-Orshikh, additional, Styczynski, Ashley R, additional, Ramay, Brooke M, additional, Kariuki, Samuel, additional, Palmer, Guy H, additional, Call, Douglas R, additional, and Omulo, Sylvia, additional

Published
2023
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11. Risk Factors for Colonization With Extended-Spectrum Cephalosporin-Resistant and Carbapenem-Resistant Enterobacterales Among Hospitalized Patients in Kenya: An Antibiotic Resistance in Communities and Hospitals (ARCH) Study

Author

Omulo, Sylvia, primary, Ita, Teresa, additional, Mugoh, Robert, additional, Ayodo, Charchil, additional, Luvsansharav, Ulzii, additional, Bollinger, Susan, additional, Styczynski, Ashley, additional, Ramay, Brooke M, additional, Caudell, Mark A, additional, Palmer, Guy H, additional, Kariuki, Samuel, additional, Call, Douglas R, additional, and Smith, Rachel M, additional

Published
2023
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15. Linking calving intervals to milk production and household nutrition in Kenya

Author

DeLay, Nathan D., Thumbi, S.M., Vanderford, Julia, Otiang, Elkanah, Ochieng, Linus, Njenga, M. Kariuki, Palmer, Guy H., and Marsh, Thomas L.

Abstract

Maternal and child under-nutrition resulting in childhood stunting remains prevalent in east Africa, leading to increased disease risk, limiting cognitive development, and impeding human capital accumulation that constrains individuals, communities, and nations from reaching their full potential. In a western Kenyan population with a high prevalence of childhood stunting, frequency of milk consumption has been shown to increase monthly height gain in children, indicating the potential to improve health through livestock productivity. However, calving rates remain low, constraining the availability of milk to the household. Here we model average herd-level calving intervals and its relation to milk yield and nutrition in the context of an agricultural household production model, applying a dynamic panel econometric approach to household level data. We provide evidence that targeted on-farm specialization leads to significantly higher calving rates and shorter calving intervals, which in turn predictably increase milk production. Importantly, we show that the positive link between calving and household milk nutrition is present across households that primarily consume milk produced on-farm (“producer-consumers”) and those that predominantly purchase milk (“milk buyers”), indicating that efforts to improve herd fertility in western Kenya could improve food security on a community scale.

Published
2024
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23. The Livestock for Health Study: A Field Trial on Livestock Interventions to Prevent Acute Malnutrition Among Women and Children in Pastoralist Communities in Northern Kenya

Author

Young, Helen, Osman, Abdal Monium, Radday, Anne, Fracassi, Patrizia, Thumbi, Samuel M., Muema, Josphat, Mutono, Nyamai, Njuguna, Joseph, Jost, Christine, Boyd, Erin, Tewoldeberhan, Daniel, Mutua, Immaculate, Gacharamu, George, Wambua, Francis, Allport, Rob, Olesambu, Emmanuella, Osman, Abdal Monium, Souza, Darana, Kimani, Irene, Oyugi, Julius, Bukania, Zipporah, Oboge, Harriet, Palmer, Guy H., and Yoder, Jonathan

Abstract

Background: Livestock-dependent communities in Africa’s drylands disproportionately experience acute malnutrition, especially during drought seasons. We detail the design and implementation of the Livestock for Health (L4H) study aimed at determining the effect of providing livestock feed and nutritional counselling to prevent seasonal spikes of acute malnutrition.Methods: The L4H study employed a 3-arm cluster randomized controlled trial to compare households in pastoralist settings in northern Kenya receiving livestock feeds during critical dry periods, with or without nutritional counseling, with control households. Over 4 dry seasons, 2019 to 2021, the study collected data on household milk production, consumption patterns, mothers’/children’s nutritional status, household socioeconomic status, herd dynamics, and human and animal health status every 6 weeks.Results: L4H recruited 1734 households, with 639, 585, and 510 households assigned to intervention arms 1 and 2 and control arm 3, respectively. From these households, 1734 women and 1748 children younger than 3 years were recruited. In total, 19 419 household visits were completed, obtaining anthropometric measures 9 times on average for each child and mother. Eighty-one households (5%) were lost from the study due to the mother’s death, child’s death, migration, and withdrawal for other reasons.Discussion: L4H’s success in a challenging environment was possible due to strong community engagement, formative studies to inform trial design, collaboration with local authorities, and effective interdisciplinary collaboration. Subsequent manuscripts will report the study findings.Trial Registration: The study was registered October 29, 2020, and is online at ClinicalTrials.gov(ID: NCT04608656).

Published
2023
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25. Anaplasma

Author

Brayton, Kelly A., Dark, Michael J., Palmer, Guy H., Nene, Vishvanath, editor, and Kole, Chittaranjan, editor

Published
2009
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26. Point-prevalence survey of antibiotic use at three public referral hospitals in Kenya

Author

Omulo, Sylvia, primary, Oluka, Margaret, additional, Achieng, Loice, additional, Osoro, Eric, additional, Kinuthia, Rosaline, additional, Guantai, Anastasia, additional, Opanga, Sylvia Adisa, additional, Ongayo, Marion, additional, Ndegwa, Linus, additional, Verani, Jennifer R., additional, Wesangula, Eveline, additional, Nyakiba, Jarred, additional, Makori, Jones, additional, Sugut, Wilson, additional, Kwobah, Charles, additional, Osuka, Hanako, additional, Njenga, M. Kariuki, additional, Call, Douglas R., additional, Palmer, Guy H., additional, VanderEnde, Daniel, additional, and Luvsansharav, Ulzii-Orshikh, additional

Published
2022
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32. 1277. Colonization Rates for Antimicrobial-resistant Bacteria in Kenya: An Antibiotic Resistance in Communities and Hospitals (ARCH) Study

Author

Omulo, Sylvia, primary, Luvsansharav, Ulzii-Orshikh, additional, Ita, Teresa, additional, Mugoh, Robert, additional, Caudell, Mark, additional, Ramay, Brooke M, additional, Palmer, Guy H, additional, Ndegwa, Linus, additional, Verani, Jennifer, additional, Bollinger, Susan, additional, Sharma, Aditya, additional, Call, Douglas, additional, and Smith, Rachel, additional

Published
2021
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35. Drivers of vaccination preferences to protect a low-value livestock resource: Willingness to pay for Newcastle disease vaccines by smallholder households

Author

Campbell, Zoë A., Otieno, Linus, Shirima, Gabriel M., Marsh, Thomas L., and Palmer, Guy H.

Subjects
Rural Population, Family Characteristics, Farms, Vaccination decision, Newcastle Disease, Ownership, Vaccination, Newcastle disease virus, Viral Vaccines, Food security, Models, Theoretical, Tanzania, Article, Poultry, Veterinary vaccines, Surveys and Questionnaires, Income, Animals, Humans, Willingness to pay, Contingent valuation, Chickens, Poverty, Poultry Diseases
Abstract

Highlights • Willingness to pay signals low income households value Newcastle disease vaccines. • Vaccination is valued despite poultry being a relatively low value asset. • On-farm income is sufficient to drive willingness to pay (WTP). • Prior vaccination increases WTP, implying vaccines are valued as being efficacious., Vaccination can be an effective risk management approach to minimize the burden of disease and increase livestock productivity for smallholder households in low income countries. In contrast to vaccination of cattle, a high-value smallholder asset, there is a significant knowledge gap for the drivers of vaccine adoption of smallholder poultry. Newcastle disease virus (NDV) causes high mortality in chickens and is one of the greatest constraints to East African poultry production. To determine preferences and willingness to pay for NDV vaccines by chicken-owning households in Tanzania, we administered a survey with a contingent valuation activity to 535 households across six villages in Arusha, Singida, and Mbeya regions. Given the low current vaccination rate, we tested the null hypothesis that smallholder households do not value NDV vaccines and found overwhelming evidence that smallholders do value NDV vaccines. The willingness to pay (WTP) estimate was 5853 Tanzanian shillings ($2.64) to vaccinate ten chickens given the vaccine was protective for a period of three months. This estimate is about twice the market price reported by households in the study areas suggesting chicken-owning households value and benefit from NDV vaccines, but face other barriers to vaccination. Previous vaccination had the largest positive effect size on WTP suggesting smallholders observe benefits from vaccinating. In contrast to studies of vaccination of higher-cost cattle where off-farm income sources often drive willingness to pay, on-farm income was a driver of WTP for NDV vaccines suggesting different drivers affect protection of low-value livestock assets as compared to high-value assets.

Published
2019

39. Additional file 4 of Carriage of antimicrobial-resistant bacteria in a high-density informal settlement in Kenya is associated with environmental risk-factors

Author

Omulo, Sylvia, Lofgren, Eric T., Lockwood, Svetlana, Thumbi, Samuel M., Bigogo, Godfrey, Ouma, Alice, Verani, Jennifer R., Bonventure Juma, M. Kariuki Njenga, Kariuki, Samuel, McElwain, Terry F., Palmer, Guy H., and Call, Douglas R.

Abstract

Additional file 4. Multivariable regression analysis for antimicrobial resistance load (Log10 CFU) at the household level. Only variables with P < 0·2 in the univariable mixed-effects model were included in the multivariable model. Regression estimates (β) and 95% confidence intervals with P < 0·05 are shown in bold. P = 0·00 indicates P < 0·01.

Published
2021
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40. Additional file 2 of Carriage of antimicrobial-resistant bacteria in a high-density informal settlement in Kenya is associated with environmental risk-factors

Author

Omulo, Sylvia, Lofgren, Eric T., Lockwood, Svetlana, Thumbi, Samuel M., Bigogo, Godfrey, Ouma, Alice, Verani, Jennifer R., Bonventure Juma, M. Kariuki Njenga, Kariuki, Samuel, McElwain, Terry F., Palmer, Guy H., and Call, Douglas R.

Abstract

Additional file 2. Antibiotic use Questionnaire.

Published
2021
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41. Additional file 1 of Carriage of antimicrobial-resistant bacteria in a high-density informal settlement in Kenya is associated with environmental risk-factors

Author

Omulo, Sylvia, Lofgren, Eric T., Lockwood, Svetlana, Thumbi, Samuel M., Bigogo, Godfrey, Ouma, Alice, Verani, Jennifer R., Bonventure Juma, M. Kariuki Njenga, Kariuki, Samuel, McElwain, Terry F., Palmer, Guy H., and Call, Douglas R.

Abstract

Additional file 1. Water, Sanitation and Hygiene Questionnaire.

Published
2021
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42. Additional file 6 of Carriage of antimicrobial-resistant bacteria in a high-density informal settlement in Kenya is associated with environmental risk-factors

Author

Omulo, Sylvia, Lofgren, Eric T., Lockwood, Svetlana, Thumbi, Samuel M., Bigogo, Godfrey, Ouma, Alice, Verani, Jennifer R., Bonventure Juma, M. Kariuki Njenga, Kariuki, Samuel, McElwain, Terry F., Palmer, Guy H., and Call, Douglas R.

Abstract

Additional file 6. Multivariable regression analysis for antimicrobial resistance load (Log10 CFU) for children aged 0–5 years. Only variables with P < 0·2 in the univariable mixed-effects model were included in the multivariable model. Regression estimates (β) and 95% confidence intervals with P < 0·05 are shown in bold. P = 0·00 indicates P < 0·01.

Published
2021
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43. Additional file 5 of Carriage of antimicrobial-resistant bacteria in a high-density informal settlement in Kenya is associated with environmental risk-factors

Author

Omulo, Sylvia, Lofgren, Eric T., Lockwood, Svetlana, Thumbi, Samuel M., Bigogo, Godfrey, Ouma, Alice, Verani, Jennifer R., Bonventure Juma, M. Kariuki Njenga, Kariuki, Samuel, McElwain, Terry F., Palmer, Guy H., and Call, Douglas R.

Abstract

Additional file 5. Multivariable regression analysis for antimicrobial resistance load (Log10 CFU) at the adult level (≥18 years). Only variables with P < 0·2 in the univariable mixed-effects model were included in the multivariable model. Regression estimates (β) and 95% confidence intervals with P < 0·05 are shown in bold. P = 0·00 indicates P < 0·01.

Published
2021
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44. Disponibilidad de antibióticos en tiendas de Guatemala

Author

Moreno, Purificación, primary, Cordón, Celia, additional, Ramay, Brooke M, additional, Grajeda, Laura, additional, Palmer, Guy H, additional, Lopez, Maria Renee, additional, Morales, Marinees, additional, Sosa, Karen, additional, Cerón, Alejandro, additional, and Call, Douglas R, additional

Published
2021
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47. Spatial and temporal risk as drivers for adoption of foot and mouth disease vaccination

Author

Railey, Ashley F., Lembo, Tiziana, Palmer, Guy H., Shirima, Gabriel M., and Marsh, Thomas L.

Subjects
Male, Temporal risk, Foot-and-Mouth Disease Virus, Foot-and-Mouth Disease, Surveys and Questionnaires, Vaccination, Uncertainty, Animals, Humans, Female, Perceived risk, Article, Spatial risk
Abstract

Highlights • The value of vaccination increases with perceived risk. • Heightened proximity of risk introduces uncertainty. • Household capacity to cope with resource constraints influences vaccination uptake. • Concerns for vaccine efficacy undermine vaccination coverage., Identifying the drivers of vaccine adoption decisions under varying levels of perceived disease risk and benefit provides insight into what can limit or enhance vaccination uptake. To address the relationship of perceived benefit relative to temporal and spatial risk, we surveyed 432 pastoralist households in northern Tanzania on vaccination for foot-and-mouth disease (FMD). Unlike human health vaccination decisions where beliefs regarding adverse, personal health effects factor heavily into perceived risk, decisions for animal vaccination focus disproportionately on dynamic risks to animal productivity. We extended a commonly used stated preference survey methodology, willingness to pay, to elicit responses for a routine vaccination strategy applied biannually and an emergency strategy applied in reaction to spatially variable, hypothetical outbreaks. Our results show that households place a higher value on vaccination as perceived risk and household capacity to cope with resource constraints increase, but that the episodic and unpredictable spatial and temporal spread of FMD contributes to increased levels of uncertainty regarding the benefit of vaccination. In addition, concerns regarding the performance of the vaccine underlie decisions for both routine and emergency vaccination, indicating a need for within community messaging and documentation of the household and population level benefits of FMD vaccination.

Published
2018

48. Analysis of the Anaplasma marginale major surface protein 1 complex protein composition by tandem mass spectrometry

Author

Macmillan, Henriette, Brayton, Kelly A., Palmer, Guy H., McGuire, Travis C., Munske, Gerhard, Siems, William F., and Brown, Wendy C.

Subjects
Mass spectrometry -- Usage, Bacterial proteins -- Research, Liquid chromatography -- Usage, Biological sciences
Abstract

The protective major surface protein 1 (MSP1) complex of Anaplasma marginale is a heteromer of MSP1a and MSP1b, encoded by a multigene family. The mspl[beta] sequences were highly conserved throughout infection. However, liquid chromatography-tandem mass spectrometry analysis identified only a single MSPlb protein, MSP1b1, within the MSP1 complex.

Published
2006

49. Carriage of antimicrobial-resistant bacteria in a high-density informal settlement in Kenya is associated with environmental risk-factors

Author

Omulo, Sylvia, primary, Lofgren, Eric T, additional, Lockwood, Svetlana, additional, Mwangi, Samuel T, additional, Bigogo, Godfrey, additional, Ouma, Alice, additional, Verani, Jennifer R., additional, Juma, Bonventure, additional, Njenga, Kariuki M, additional, Kariuki, Samuel, additional, McElwain, Terry F, additional, Palmer, Guy H, additional, and Call, Douglas R, additional

Published
2020
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50. Point-Prevalence Surveys of Antibiotic Use at Three Large Public Hospitals in Kenya

Author

Omulo, Sylvia, primary, Oluka, Margaret, additional, Ombajo, Loice, additional, Osoro, Eric, additional, Kinuthia, Rosaline, additional, Guantai, Anastasia, additional, Ndegwa, Linus, additional, Verani, Jennifer, additional, Opanga, Sylvia, additional, Wesangula, Evelyn, additional, Nyakiba, Jarred, additional, Makori, Jones, additional, Kwobah, Charles, additional, Sugut, Wilson, additional, Osuka, Hanako, additional, Njenga, M. Kariuki, additional, Call, Douglas, additional, Palmer, Guy H., additional, VanderEnde, Daniel, additional, and Luvsansharav, Ulzii-Oshikh, additional

Published
2020
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