Last data update: Dec 02, 2024. (Total: 48272 publications since 2009)
Records 1-28 (of 28 Records) |
Query Trace: Parsons MB[original query] |
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Burden of Diarrheagenic Escherichia coli in Santa Rosa, Guatemala in active health-services surveillance during 2008-2009 and 2014-2015.
Jarquin C , Morales O , McCracken JP , Lopez MR , Lopez B , Reyes L , Gmez GA , Bryan JP , Peruski LF , Pattabiraman V , Parsons MB . Trop Med Int Health 2022 27 (4) 408-417 OBJECTIVE: To describe the epidemiology of laboratory-confirmed Diarrheagenic Escherichia coli (DEC) cases from active facility-based surveillance in Guatemala. METHODS: We collected clinical and risk factor data on enrolled patients (aged 0-52 years) with acute diarrhea at government healthcare facilities (1 hospital and 6 clinics) in Santa Rosa, Guatemala, during 2008-2009 and 2014-2015. Stool samples were analyzed and E. coli identified through culture and biochemical tests, PCR amplification of genes encoding pathotype-specific virulence factors identified specific DEC pathotypes. Healthcare-seeking adjusted incidence rates were calculated. RESULTS: 3041 diarrhea cases were captured by surveillance (647 hospitalizations (H), 2394 clinic visits (CV)); general E. coli prevalence was 17.9%. DEC pathotypes were identified in 19% (n=95/497) and 21% (n=450/2113) in diarrhea H and CV, respectively. Enteropathogenic E. coli (EPEC) was most frequently isolated (8.2% (n=41) in diarrhea H, 12.0% (n =255) in diarrhea CV), followed by ETEC (6.8% (n=34) in H, 6% (n=128) in CV) and STEC (0.6% (n=3) in H, 0.6% (n=13) in CV). We did not find evidence of a difference in severity between DEC and non-DEC diarrhea. Incidence of DEC clinic visits and hospitalizations was 648.0 and 29.3, respectively, per 10,000 persons aged 5 years and 36.8 and 0.4, respectively, per 10,000 persons aged >5 years. CONCLUSIONS: DEC pathotypes, especially EPEC and ETEC, were detected frequently from patients presenting with diarrheal illness in Santa Rosa, Guatemala. Our findings suggest that preventive interventions should be prioritized for young children. |
The Gombe Ecosystem Health Project: 16 years of program evolution and lessons learned
Lonsdorf EV , Travis DA , Raphael J , Kamenya S , Lipende I , Mwacha D , Collins DA , Wilson M , Mjungu D , Murray C , Bakuza J , Wolf TM , Parsons MB , Deere JR , Lantz E , Kinsel MJ , Santymire R , Pintea L , Terio KA , Hahn BH , Pusey AE , Goodall J , Gillespie TR . Am J Primatol 2021 84 e23300 Infectious disease outbreaks pose a significant threat to the conservation of chimpanzees (Pan troglodytes) and all threatened nonhuman primates. Characterizing and mitigating these threats to support the sustainability and welfare of wild populations is of the highest priority. In an attempt to understand and mitigate the risk of disease for the chimpanzees of Gombe National Park, Tanzania, we initiated a long-term health-monitoring program in 2004. While the initial focus was to expand the ongoing behavioral research on chimpanzees to include standardized data on clinical signs of health, it soon became evident that the scope of the project would ideally include diagnostic surveillance of pathogens for all primates (including people) and domestic animals, both within and surrounding the National Park. Integration of these data, along with in-depth post-mortem examinations, have allowed us to establish baseline health indicators to inform outbreak response. Here, we describe the development and expansion of the Gombe Ecosystem Health project, review major findings from the research and summarize the challenges and lessons learned over the past 16 years. We also highlight future directions and present the opportunities and challenges that remain when implementing studies of ecosystem health in a complex, multispecies environment. |
Antimicrobial Resistance Creates Threat to Chimpanzee Health and Conservation in the Wild.
Parsons MB , Travis DA , Lonsdorf EV , Lipende I , Elchoufi D , Gilagiza B , Collins A , Kamenya S , Tauxe RV , Gillespie TR . Pathogens 2021 10 (4) Infectious disease is recognized as the greatest threat to the endangered chimpanzees made famous by the groundbreaking work of Dr. Jane Goodall at Gombe National Park (GNP), Tanzania. The permeable boundary of this small protected area allows for regular wildlife-human and wildlife-domestic animal overlap, which may facilitate cross-species transmission of pathogens and antimicrobial resistance. Few studies have examined the prevalence of antimicrobial resistance in wild ape populations. We used molecular techniques to investigate the presence of genes conferring resistance to sulfonamides (often used to treat diarrheal illness in human settings in this region) and tetracycline (used in the past-though much less so now) in fecal specimens from humans, domestic animals, chimpanzees, and baboons in and around GNP. We also tested stream water used by these groups. Sulfonamide resistance was common in humans (74%), non-human primates (43%), and domestic animals (17%). Tetracycline resistance was less common in all groups: humans (14%), non-human primates (3%), and domestic animals (6%). Sul resistance genes were detected from 4/22 (18%) of streams sampled. Differences in sul gene frequencies did not vary by location in humans nor in chimpanzees. |
Factors associated with typical enteropathogenic Escherichia coli infection among children <5 years old with moderate-to-severe diarrhoea in rural western Kenya, 2008-2012.
Fagerli K , Omore R , Kim S , Ochieng JB , Ayers TL , Juma J , Farag TH , Nasrin D , Panchalingam S , Robins-Browne RM , Nataro JP , Kotloff KL , Levine MM , Oundo J , Parsons MB , Laserson KF , Mintz ED , Breiman RF , O'Reilly CE . Epidemiol Infect 2020 148 1-37 Typical enteropathogenic Escherichia coli (tEPEC) infection is a major cause of diarrhoea and contributor to mortality in children <5 years old in developing countries. Data were analysed from the Global Enteric Multicenter Study examining children <5 years old seeking care for moderate-to-severe diarrhoea (MSD) in Kenya. Stool specimens were tested for enteric pathogens, including by multiplex polymerase chain reaction for gene targets of tEPEC. Demographic, clinical and anthropometric data were collected at enrolment and ~60-days later; multivariable logistic regressions were constructed. Of 1778 MSD cases enrolled from 2008 to 2012, 135 (7.6%) children tested positive for tEPEC. In a case-to-case comparison among MSD cases, tEPEC was independently associated with presentation at enrolment with a loss of skin turgor (adjusted odds ratio (aOR) 2.08, 95% confidence interval (CI) 1.37-3.17), and convulsions (aOR 2.83, 95% CI 1.12-7.14). At follow-up, infants with tEPEC compared to those without were associated with being underweight (OR 2.2, 95% CI 1.3-3.6) and wasted (OR 2.5, 95% CI 1.3-4.6). Among MSD cases, tEPEC was associated with mortality (aOR 2.85, 95% CI 1.47-5.55). This study suggests that tEPEC contributes to morbidity and mortality in children. Interventions aimed at defining and reducing the burden of tEPEC and its sequelae should be urgently investigated, prioritised and implemented. |
Incidence and etiology of infectious diarrhea from a facility-based surveillance system in Guatemala, 2008-2012
Arvelo W , Hall AJ , Henao O , Lopez B , Bernart C , Moir JC , Reyes L , Montgomery SP , Morgan O , Estevez A , Parsons MB , Lopez MR , Gomez G , Vinje J , Gregoricus N , Parashar U , Mintz ED , McCracken J , Bryan JP , Lindblade KA . BMC Public Health 2019 19 (1) 1340 BACKGROUND: Diarrhea is a major cause of morbidity and mortality, yet incidence and etiology data are limited. We conducted laboratory-based diarrhea surveillance in Guatemala. METHODS: A diarrhea case was defined as >/=3 loose stools in a 24-h period in a person presenting to the surveillance facilities. Epidemiologic data and stool specimens were collected. Specimens were tested for bacterial, parasitic, and viral pathogens. Yearly incidence was adjusted for healthcare seeking behaviors determined from a household survey conducted in the surveillance catchment area. RESULTS: From November 2008 to December 2012, the surveillance system captured 5331 diarrhea cases; among these 1381 (26%) had specimens tested for all enteric pathogens of interest. The adjusted incidence averaged 659 diarrhea cases per 10,000 persons per year, and was highest among children aged < 5 years, averaging 1584 cases per 10,000 children per year. Among 1381 (26%) specimens tested for all the pathogens of interest, 235 (17%) had a viral etiology, 275 (20%) had a bacterial, 50 (4%) had parasites, and 86 (6%) had co-infections. Among 827 (60%) specimens from children aged < 5 years, a virus was identified in 196 (23%) patients; 165 (20%) had norovirus and 99 (12%) rotavirus, including co-infections. Among 554 patients aged >/=5 years, 103 (19%) had a bacterial etiology, including diarrheagenic Escherichia coli in 94 (17%) cases, Shigella spp. in 31 (6%), Campylobacter spp. in 5 (1%), and Salmonella spp. in 4 (1%) cases. Detection of Giardia and Cryptosporidium was infrequent (73 cases; 5%). CONCLUSIONS: There was a substantial burden of viral and bacterial diarrheal diseases in Guatemala, highlighting the importance of strengthening laboratory capacity for rapid detection and control and for evaluation of public health interventions. |
Entamoeba histolytica infection in humans, chimpanzees and baboons in the Greater Gombe Ecosystem, Tanzania
Deere JR , Parsons MB , Lonsdorf EV , Lipende I , Kamenya S , Collins DA , Travis DA , Gillespie TR . Parasitology 2018 146 (9) 1-7 Entamoeba histolytica is an enteric parasite that infects approximately 50 million people worldwide. Although E. histolytica is a zoonotic parasite that has the potential to infect nonhuman primates, such transmission is poorly understood. Consequently, this study examined whether E. histolytica is present among humans, chimpanzees and baboons living in the Greater Gombe Ecosystem (GGE), Tanzania. The primary aims were to determine patterns of E. histolytica infection in a system with human-nonhuman primate overlap and to test associations between infection status and potential risk factors of disease. Entamoeba spp. occurred in 60.3% of human, 65.6% of chimpanzee and 88.6% of baboon samples. Entamoeba histolytica occurred in 12.1% of human, 34.1% of chimpanzee and 10.9% of baboon samples. Human E. histolytica infection was associated with gastrointestinal symptoms. This was the first study to confirm the presence of E. histolytica in the GGE. The high sample prevalence of E. histolytica in three sympatric primates suggests that zoonotic transmission is possible and stresses the need for further phylogenetic studies. Interventions targeting better sanitation and hygiene practices for humans living in the GGE can help prevent E. histolytica infection in humans, while also protecting the endangered chimpanzees and other primates in this region. |
Clinical, environmental, and behavioral characteristics associated with Cryptosporidium infection among children with moderate-to-severe diarrhea in rural western Kenya, 2008-2012: The Global Enteric Multicenter Study (GEMS)
Delahoy MJ , Omore R , Ayers TL , Schilling KA , Blackstock AJ , Ochieng JB , Moke F , Jaron P , Awuor A , Okonji C , Juma J , Farag TH , Nasrin D , Panchalingam S , Nataro JP , Kotloff KL , Levine MM , Oundo J , Roellig DM , Xiao L , Parsons MB , Laserson K , Mintz ED , Breiman RF , O'Reilly CE . PLoS Negl Trop Dis 2018 12 (7) e0006640 BACKGROUND: Cryptosporidium is a leading cause of moderate-to-severe diarrhea (MSD) in young children in Africa. We examined factors associated with Cryptosporidium infection in MSD cases enrolled at the rural western Kenya Global Enteric Multicenter Study (GEMS) site from 2008-2012. METHODOLOGY/PRINCIPAL FINDINGS: At health facility enrollment, stool samples were tested for enteric pathogens and data on clinical, environmental, and behavioral characteristics collected. Each child's health status was recorded at 60-day follow-up. Data were analyzed using logistic regression. Of the 1,778 children with MSD enrolled as cases in the GEMS-Kenya case-control study, 11% had Cryptosporidium detected in stool by enzyme immunoassay; in a genotyped subset, 81% were C. hominis. Among MSD cases, being an infant, having mucus in stool, and having prolonged/persistent duration diarrhea were associated with being Cryptosporidium-positive. Both boiling drinking water and using rainwater as the main drinking water source were protective factors for being Cryptosporidium-positive. At follow-up, Cryptosporidium-positive cases had increased odds of being stunted (adjusted odds ratio [aOR] = 1.65, 95% CI: 1.06-2.57), underweight (aOR = 2.08, 95% CI: 1.34-3.22), or wasted (aOR = 2.04, 95% CI: 1.21-3.43), and had significantly larger negative changes in height- and weight-for-age z-scores from enrollment. CONCLUSIONS/SIGNIFICANCE: Cryptosporidium contributes significantly to diarrheal illness in young children in western Kenya. Advances in point of care detection, prevention/control approaches, effective water treatment technologies, and clinical management options for children with cryptosporidiosis are needed. |
Zoonotic disease programs for enhancing global health security
Belay ED , Kile JC , Hall AJ , Barton-Behravesh C , Parsons MB , Salyer S , Walke H . Emerg Infect Dis 2017 23 (13) S65-70 Most infectious diseases that recently emerged in humans originated in animals. Besides close contact between animals and humans, other factors probably contribute to the cross-species transmission of infectious diseases. It is critical to establish effective mechanisms for coordination and collaboration between the animal, human, and environmental health sectors before new threats emerge by bringing the different sectors together to tackle endemic zoonotic diseases of greatest concern. Such multisectoral partnerships should begin by identifying priority zoonotic diseases for national engagement with equal input from the different sectors. Improvements in surveillance and data sharing for prioritized zoonotic diseases and enhancements of laboratory testing and joint outbreak response capacities in the human and animal health sectors will create and strengthen the mechanisms necessary to effectively detect and respond to emerging health threats, and thereby enhance global health security. |
Animal-related factors associated with moderate-to-severe diarrhea in children younger than five years in western Kenya: A matched case-control study
Conan A , O'Reilly CE , Ogola E , Ochieng JB , Blackstock AJ , Omore R , Ochieng L , Moke F , Parsons MB , Xiao L , Roellig D , Farag TH , Nataro JP , Kotloff KL , Levine MM , Mintz ED , Breiman RF , Cleaveland S , Knobel DL . PLoS Negl Trop Dis 2017 11 (8) e0005795 BACKGROUND: Diarrheal disease remains among the leading causes of global mortality in children younger than 5 years. Exposure to domestic animals may be a risk factor for diarrheal disease. The objectives of this study were to identify animal-related exposures associated with cases of moderate-to-severe diarrhea (MSD) in children in rural western Kenya, and to identify the major zoonotic enteric pathogens present in domestic animals residing in the homesteads of case and control children. METHODOLOGY/PRINCIPAL FINDINGS: We characterized animal-related exposures in a subset of case and control children (n = 73 pairs matched on age, sex and location) with reported animal presence at home enrolled in the Global Enteric Multicenter Study in western Kenya, and analysed these for an association with MSD. We identified potentially zoonotic enteric pathogens in pooled fecal specimens collected from domestic animals resident at children's homesteads. Variables that were associated with decreased risk of MSD were washing hands after animal contact (matched odds ratio [MOR] = 0.2; 95% CI 0.08-0.7), and presence of adult sheep that were not confined in a pen overnight (MOR = 0.1; 0.02-0.5). Variables that were associated with increased risk of MSD were increasing number of sheep owned (MOR = 1.2; 1.0-1.5), frequent observation of fresh rodent excreta (feces/urine) outside the house (MOR = 7.5; 1.5-37.2), and participation of the child in providing water to chickens (MOR = 3.8; 1.2-12.2). Of 691 pooled specimens collected from 2,174 domestic animals, 159 pools (23%) tested positive for one or more potentially zoonotic enteric pathogens (Campylobacter jejuni, C. coli, non-typhoidal Salmonella, diarrheagenic E. coli, Giardia, Cryptosporidium, or rotavirus). We did not find any association between the presence of particular pathogens in household animals, and MSD in children. CONCLUSIONS AND SIGNIFICANCE: Public health agencies should continue to promote frequent hand washing, including after animal contact, to reduce the risk of MSD. Future studies should address specific causal relations of MSD with sheep and chicken husbandry practices, and with the presence of rodents. |
Factors associated with the duration of moderate-to-severe diarrhea among children in rural western Kenya enrolled in the Global Enteric Multicenter Study, 2008-2012
Schilling KA , Omore R , Derado G , Ayers T , Ochieng JB , Farag TH , Nasrin D , Panchalingam S , Nataro JP , Kotloff KL , Levine MM , Oundo J , Parsons MB , Bopp C , Laserson K , Stauber CE , Rothenberg R , Breiman RF , O'Reilly CE , Mintz ED . Am J Trop Med Hyg 2017 97 (1) 248-258 Diarrheal disease is a leading cause of death among young children worldwide. As rates of acute diarrhea (AD; 1-6 days duration) have decreased, persistent diarrhea (PD; > 14 days duration) accounts for a greater proportion of the diarrheal disease burden. We describe factors associated with the duration of moderate-to-severe diarrhea in Kenyan children < 5 years old enrolled in the Global Enteric Multicenter Study. We found 587 (58%) children experienced AD, 360 (35%) had prolonged acute diarrhea (ProAD; 7-13 days duration), and 73 (7%) had PD. We constructed a Cox proportional hazards model to identify factors associated with diarrheal duration. Risk factors independently associated with longer diarrheal duration included infection with Cryptosporidium (hazard ratio [HR]: 0.868, P = 0.035), using an unimproved drinking water source (HR: 0.87, P = 0.035), and being stunted at enrollment (HR: 0.026, P < 0.0001). Diarrheal illness of extended duration appears to be multifactorial; given its association with adverse health and development outcomes, effective strategies should be implemented to reduce the duration and severity of diarrheal illness. Effective treatments for Cryptosporidium should be identified, interventions to improve drinking water are imperative, and nutrition should be improved through exclusive breastfeeding in infants ≤ 6 months and appropriate continued feeding practices for ill children. |
Vibriosis, not cholera: toxigenic Vibrio cholerae non-O1, non-O139 infections in the United States, 1984-2014
Crowe SJ , Newton AE , Gould LH , Parsons MB , Stroika S , Bopp CA , Freeman M , Greene K , Mahon BE . Epidemiol Infect 2016 144 (15) 1-7 Toxigenic strains of Vibrio cholerae serogroups O1 and O139 have caused cholera epidemics, but other serogroups - such as O75 or O141 - can also produce cholera toxin and cause severe watery diarrhoea similar to cholera. We describe 31 years of surveillance for toxigenic non-O1, non-O139 infections in the United States and map these infections to the state where the exposure probably originated. While serogroups O75 and O141 are closely related pathogens, they differ in how and where they infect people. Oysters were the main vehicle for O75 infection. The vehicles for O141 infection include oysters, clams, and freshwater in lakes and rivers. The patients infected with serogroup O75 who had food traceback information available ate raw oysters from Florida. Patients infected with O141 ate oysters from Florida and clams from New Jersey, and those who only reported being exposed to freshwater were exposed in Arizona, Michigan, Missouri, and Texas. Improving the safety of oysters, specifically, should help prevent future illnesses from these toxigenic strains and similar pathogenic Vibrio species. Post-harvest processing of raw oysters, such as individual quick freezing, heat-cool pasteurization, and high hydrostatic pressurization, should be considered. |
Epidemiology, seasonality and factors associated with rotavirus infection among children with moderate-to-severe diarrhea in rural western Kenya, 2008-2012: The Global Enteric Multicenter Study (GEMS)
Omore R , Tate JE , O'Reilly CE , Ayers T , Williamson J , Moke F , Schilling KA , Awuor AO , Jaron P , Ochieng JB , Oundo J , Parashar UD , Parsons MB , Bopp CC , Nasrin D , Farag TH , Kotloff KL , Nataro JP , Panchalingam S , Levine MM , Laserson KF , Nuorti JP , Mintz ED , Breiman RF . PLoS One 2016 11 (8) e0160060 OBJECTIVE: To evaluate factors associated with rotavirus diarrhea and to describe severity of illness among children <5 years old with non-dysenteric, moderate-to-severe diarrhea (MSD) in rural western Kenya. METHODS: We analyzed data from children <5 years old with non-dysenteric MSD enrolled as cases in the Global Enteric Multicenter Study (GEMS) in Kenya. A non-dysenteric MSD case was defined as a child with ≥3 loose stools in 24 hrs. and one or more of the following: sunken eyes, skin tenting, intravenous rehydration, or hospitalization, who sought care at a sentinel health center within 7 days of illness onset. Rotavirus antigens in stool samples were detected by ELISA. Demographic and clinical information was collected at enrollment and during a single follow-up home visit at approximately 60 days. We analyzed diarrhea severity using a GEMS 17 point numerical scoring system adapted from the Vesikari score. We used logistic regression to evaluate factors associated with rotavirus infection. RESULTS: From January 31, 2008 to September 30, 2012, among 1,637 (92%) non-dysenteric MSD cases, rotavirus was detected in stools of 245 (15.0%). Rotavirus-positive compared with negative cases were: younger (median age, 8 vs. 13 months; p<0.0001), had more severe illness (median severity score, 9 vs 8; p<0.0001) and had to be hospitalized more frequently (37/245 [15.1%] vs. 134/1,392 [9.6%]), p <0.013). Independent factors associated with rotavirus infection included age 0-11 months old (aOR = 5.29, 95% CI 3.14-8.89) and presenting with vomiting ≥3 times/24hrs (aOR = 2.58, 95% CI [1.91-3.48]). Rotavirus was detected more commonly in warm and dry months than in the cool and rainy months (142/691 [20%] vs 70/673 [10%]) p<0.0001). CONCLUSIONS: Diarrhea caused by rotavirus is associated with severe symptoms leading to hospitalization. Consistent with other settings, infants had the greatest burden of disease. |
Real-Time TaqMan PCR Assay for the Detection of Heat-Labile and Heat-Stable Enterotoxin Genes in a Geographically Diverse Collection of Enterotoxigenic Escherichia coli Strains and Stool Specimens.
Pattabiraman V , Parsons MB , Bopp CA . Foodborne Pathog Dis 2016 13 (4) 212-20 Enterotoxigenic Escherichia coli (ETEC) are an important cause of diarrhea in children under the age of 5 years in developing countries and are the leading bacterial agent of traveler's diarrhea in persons traveling to these countries. ETEC strains secrete heat-labile (LT) and/or heat-stable (ST) enterotoxins that induce diarrhea by causing water and electrolyte imbalance. We describe the validation of a real-time TaqMan PCR (RT-PCR) assay to detect LT, ST1a, and ST1b enterotoxin genes in E. coli strains and in stool specimens. We validated LT/ST1b duplex and ST1a single-plex RT-PCR assay using a conventional PCR assay as a gold standard with 188 ETEC strains and 42 non-ETEC strains. We validated LT/ST1b duplex and ST1a single-plex RT-PCR assay in stool specimens (n = 106) using traditional culture as the gold standard. RT- PCR assay sensitivities for LT, ST1a, and ST1b detection in strains were 100%, 100%, and 98%; specificities were 95%, 98%, and 99%, and Pearson correlation coefficient r was 0.9954 between RT-PCR assay and the gold standard. In stool specimens, RT-PCR assay sensitivities for LT, ST1a, and ST1b detection were 97%, 100%, and 97%; and specificities were 99%, 94%, and 97%. Pearson correlation coefficient r was 0.9975 between RT-PCR results in stool specimens and the gold standard. Limits of detection of LT, ST1a, and ST1b by RT-PCR assay were 0.1 to1.0 pg/muL and by conventional PCR assay were 100 to1000 pg/muL. The accuracy, rapidity and sensitivity of this RT-PCR assay is promising for ETEC detection in public health/clinical laboratories and for laboratories in need of an independent method to confirm results of other culture independent diagnostic tests. |
Emergence of community-acquired, multidrug-resistant invasive nontyphoidal Salmonella disease in rural western Kenya, 2009-2013
Oneko M , Kariuki S , Muturi-Kioi V , Otieno K , Otieno VO , Williamson JM , Folster J , Parsons MB , Slutsker L , Mahon BE , Hamel MJ . Clin Infect Dis 2015 61 Suppl 4 S310-6 BACKGROUND: Nontyphoidal Salmonella (NTS), mainly serotypes Typhimurium and Enteritidis, cause invasive infections with high mortality in children in sub-Saharan Africa. Multidrug resistance is common, and resistance to third-generation cephalosporins has emerged. METHODS: We reviewed clinical features, outcomes, and antimicrobial resistance patterns in invasive NTS infections among children aged 6 weeks to 5 years participating in malaria vaccine studies in an area of high malaria and human immunodeficiency virus (HIV) transmission in Siaya, western Kenya. Blood culture was performed in hospitalized children and pediatric outpatients with prolonged fever. RESULTS: From July 2009 to December 2013, 1696 children aged 6 weeks to 17 months were enrolled into vaccine trials and followed for up to 53 months. We obtained 1692 blood cultures from 847 children. Of 134 bacterial pathogens isolated, 102 (76.1%) were Salmonella serogroup B or D. Invasive NTS disease occurred in 94 (5.5%) children, with an incidence of 1870, 4134, and 6510 episodes per 100 000 person-years overall, in infants, and in HIV-infected children, respectively. Malaria infection within the past 2 weeks occurred in 18.8% (3/16) of invasive NTS episodes in HIV-infected and 66.2% (53/80) in HIV-uninfected children. Case fatality rate was 3.1%. Salmonella group B resistant to ceftriaxone emerged in 2009 and 2010 (6.2% [2/32 isolates]), rising to 56.5% (13/23 isolates) in 2012 and 2013. CONCLUSIONS: Incidence of invasive NTS disease was high in this area of high malaria and HIV transmission, especially in HIV-infected children. Rapidly emerging resistance against ceftriaxone requires urgent reevaluation of antibiotic recommendations and primary prevention of exposure to Salmonella. |
Insights into the environmental reservoir of pathogenic Vibrio parahaemolyticus using comparative genomics.
Hazen TH , Lafon PC , Garrett NM , Lowe TM , Silberger DJ , Rowe LA , Frace M , Parsons MB , Bopp CA , Rasko DA , Sobecky PA . Front Microbiol 2015 6 204 Vibrio parahaemolyticus is an aquatic halophilic bacterium that occupies estuarine and coastal marine environments, and is a leading cause of seafood-borne food poisoning cases. To investigate the environmental reservoir and potential gene flow that occurs among V. parahaemolyticus isolates, the virulence-associated gene content and genome diversity of a collection of 133 V. parahaemolyticus isolates were analyzed. Phylogenetic analysis of housekeeping genes, and pulsed-field gel electrophoresis, demonstrated that there is genetic similarity among V. parahaemolyticus clinical and environmental isolates. Whole-genome sequencing and comparative analysis of six representative V. parahaemolyticus isolates was used to identify genes that are unique to the clinical and environmental isolates examined. Comparative genomics demonstrated an O3:K6 environmental isolate, AF91, which was cultured from sediment collected in Florida in 2006, has significant genomic similarity to the post-1995 O3:K6 isolates. However, AF91 lacks the majority of the virulence-associated genes and genomic islands associated with these highly virulent post-1995 O3:K6 genomes. These findings demonstrate that although they do not contain most of the known virulence-associated regions, some V. parahaemolyticus environmental isolates exhibit significant genetic similarity to clinical isolates. This highlights the dynamic nature of the V. parahaemolyticus genome allowing them to transition between aquatic and host-pathogen states. |
Epidemiology and molecular characterization of Cryptosporidium spp. in humans, wild primates, and domesticated animals in the Greater Gombe Ecosystem, Tanzania.
Parsons MB , Travis D , Lonsdorf EV , Lipende I , Roellig DM , Kamenya S , Zhang H , Xiao L , Gillespie TR . PLoS Negl Trop Dis 2015 9 (2) e0003529 Cryptosporidium is an important zoonotic parasite globally. Few studies have examined the ecology and epidemiology of this pathogen in rural tropical systems characterized by high rates of overlap among humans, domesticated animals, and wildlife. We investigated risk factors for Cryptosporidium infection and assessed cross-species transmission potential among people, non-human primates, and domestic animals in the Gombe Ecosystem, Kigoma District, Tanzania. A cross-sectional survey was designed to determine the occurrence and risk factors for Cryptosporidium infection in humans, domestic animals and wildlife living in and around Gombe National Park. Diagnostic PCR revealed Cryptosporidium infection rates of 4.3% in humans, 16.0% in non-human primates, and 9.6% in livestock. Local streams sampled were negative. DNA sequencing uncovered a complex epidemiology for Cryptosporidium in this system, with humans, baboons and a subset of chimpanzees infected with C. hominis subtype IfA12G2; another subset of chimpanzees infected with C. suis; and all positive goats and sheep infected with C. xiaoi. For humans, residence location was associated with increased risk of infection in Mwamgongo village compared to one camp (Kasekela), and there was an increased odds for infection when living in a household with another positive person. Fecal consistency and other gastrointestinal signs did not predict Cryptosporidium infection. Despite a high degree of habitat overlap between village people and livestock, our results suggest that there are distinct Cryptosporidium transmission dynamics for humans and livestock in this system. The dominance of C. hominis subtype IfA12G2 among humans and non-human primates suggest cross-species transmission. Interestingly, a subset of chimpanzees was infected with C. suis. We hypothesize that there is cross-species transmission from bush pigs (Potaochoerus larvatus) to chimpanzees in Gombe forest, since domesticated pigs are regionally absent. Our findings demonstrate a complex nature of Cryptosporidium in sympatric primates, including humans, and stress the need for further studies. |
Complex epidemiology and zoonotic potential for Cryptosporidium suis in rural Madagascar
Bodager JR , Parsons MB , Wright PC , Rasambainarivo F , Roellig D , Xiao L , Gillespie TR . Vet Parasitol 2014 207 140-3 Cryptosporidium spp. is the most important parasitic diarrheal agent in the world, is among the top four causes of moderate-to-severe diarrheal disease in young children in developing nations, and is problematic as an opportunistic co-infection with HIV. In addition, Cryptosporidium is a persistent challenge for livestock production. Despite its zoonotic potential, few studies have examined the ecology and epidemiology of this pathogen in rural systems characterized by high rates of overlap among humans, domesticated animals, and wildlife. To improve our understanding of the zoonotic potential of Cryptosporidium species in the rural tropics, we screened humans, livestock, peridomestic rodents, and wildlife using PCR-RFLP and sequencing-based approaches to distinguish species of Cryptosporidium in rural southeastern Madagascar. Cryptosporidium of multiple species/genotypes were apparent in this study system. Interestingly, C. suis was the dominant species of Cryptosporidium in the region, infecting humans (n=1), cattle (n=18), pigs (n=3), and rodents (n=1). The broad species range of C. suis and the lack of common cattle Cryptosporidium species (Cryptosporidium parvum and Cryptosporidium andersoni) in this system are unique. This report represents the fifth confirmed case of C. suis infection in humans, and the first case in Africa. Few rural human and livestock populations have been screened for Cryptosporidium using genus-specific genotyping methods. Consequently, C. suis may be more widespread in human and cattle populations than previously believed. |
Global positioning system data-loggers: a tool to quantify fine-scale movement of domestic animals to evaluate potential for zoonotic transmission to an endangered wildlife population
Parsons MB , Gillespie TR , Lonsdorf EV , Travis D , Lipende I , Gilagiza B , Kamenya S , Pintea L , Vazquez-Prokopec GM . PLoS One 2014 9 (11) e110984 Domesticated animals are an important source of pathogens to endangered wildlife populations, especially when anthropogenic activities increase their overlap with humans and wildlife. Recent work in Tanzania reports the introduction of Cryptosporidium into wild chimpanzee populations and the increased risk of ape mortality associated with SIVcpz-Cryptosporidium co-infection. Here we describe the application of novel GPS technology to track the mobility of domesticated animals (27 goats, 2 sheep and 8 dogs) with the goal of identifying potential routes for Cryptosporidium introduction into Gombe National Park. Only goats (5/27) and sheep (2/2) were positive for Cryptosporidium. Analysis of GPS tracks indicated that a crop field frequented by both chimpanzees and domesticated animals was a potential hotspot for Cryptosporidium transmission. This study demonstrates the applicability of GPS data-loggers in studies of fine-scale mobility of animals and suggests that domesticated animal-wildlife overlap should be considered beyond protected boundaries for long-term conservation strategies. |
Cholera in the United States, 2001-2011: a reflection of patterns of global epidemiology and travel
Loharikar A , Newton AE , Stroika S , Freeman M , Greene KD , Parsons MB , Bopp C , Talkington D , Mintz ED , Mahon BE . Epidemiol Infect 2014 143 (4) 1-9 US cholera surveillance offers insight into global and domestic trends. Between 2001 and 2011, 111 cases were reported to the Centers for Disease Control and Prevention. Cholera was associated with international travel in 90 (81%) patients and was domestically acquired in 20 (18%) patients; for one patient, information was not available. From January 2001 to October 2010, the 42 (47%) travel-associated cases were associated with travel to Asia. In October 2010, a cholera epidemic started in Haiti, soon spreading to the Dominican Republic (Hispaniola). From then to December 2011, 40 (83%) of the 48 travel-associated cases were associated with travel to Hispaniola. Of 20 patients who acquired cholera domestically, 17 (85%) reported seafood consumption; 10 (59%) ate seafood from the US Gulf Coast. In summary, an increase in travel-associated US cholera cases was associated with epidemic cholera in Hispaniola in 2010-2011. Travel to Asia and consumption of Gulf Coast seafood remained important sources of US cholera cases. |
Burden of laboratory-confirmed Campylobacter infections in Guatemala 2008-2012: results from a facility-based surveillance system
Benoit SR , Lopez B , Arvelo W , Henao O , Parsons MB , Reyes L , Moir JC , Lindblade K . J Epidemiol Glob Health 2014 4 (1) 51-9 INTRODUCTION: Campylobacteriosis is one of the leading causes of gastroenteritis worldwide. This study describes the epidemiology of laboratory-confirmed Campylobacter diarrheal infections in two facility-based surveillance sites in Guatemala. METHODS: Clinical, epidemiologic, and laboratory data were collected on patients presenting with acute diarrhea from select healthcare facilities in the departments of Santa Rosa and Quetzaltenango, Guatemala, from January 2008 through August 2012. Stool specimens were cultured for Campylobacter and antimicrobial susceptibility testing was performed on a subset of isolates. Multidrug resistance (MDR) was defined as resistance to 3 antimicrobial classes. RESULTS: Campylobacter was isolated from 306 (6.0%) of 5137 stool specimens collected. For children <5years of age, annual incidence was as high as 1288.8 per 100,000 children in Santa Rosa and 185.5 per 100,000 children in Quetzaltenango. Among 224 ambulatory care patients with Campylobacter, 169 (75.5%) received metronidazole or trimethoprim-sulfamethoxazole, and 152 (66.7%) received or were prescribed oral rehydration therapy. Antimicrobial susceptibilities were tested in 96 isolates; 57 (59.4%) were resistant to ciprofloxacin and 12 (12.5%) were MDR. CONCLUSION: Campylobacter was a major cause of diarrhea in children in two departments in Guatemala; antimicrobial resistance was high, and treatment regimens in the ambulatory setting which included metronidazole and trimethoprim-sulfamethoxazole and lacked oral rehydration were sub-optimal. |
Laboratory-confirmed cholera and rotavirus among patients with acute diarrhea in four hospitals in Haiti, 2012-2013
Steenland MW , Joseph GA , Lucien MA , Freeman N , Hast M , Nygren BL , Leshem E , Juin S , Parsons MB , Talkington DF , Mintz ED , Vertefeuille J , Balajee SA , Boncy J , Katz MA . Am J Trop Med Hyg 2013 89 (4) 641-6 An outbreak of cholera began in Haiti in October of 2010. To understand the progression of epidemic cholera in Haiti, in April of 2012, we initiated laboratory-enhanced surveillance for diarrheal disease in four Haitian hospitals in three departments. At each site, we sampled up to 10 hospitalized patients each week with acute watery diarrhea. We tested 1,616 specimens collected from April 2, 2012 to March 28, 2013; 1,030 (63.7%) specimens yielded Vibrio cholerae, 13 (0.8%) specimens yielded Shigella, 6 (0.4%) specimens yielded Salmonella, and 63 (3.9%) specimens tested positive for rotavirus. Additionally, 13.5% of children < 5 years old tested positive for rotavirus. Of 1,030 V. cholerae isolates, 1,020 (99.0%) isolates were serotype Ogawa, 9 (0.9%) isolates were serotype Inaba, and 1 isolate was non-toxigenic V. cholerae O139. During 1 year of surveillance, toxigenic cholera continued to be the main cause of acute diarrhea in hospitalized patients, and rotavirus was an important cause of diarrhea-related hospitalizations in children. |
Biochemical, serological, and virulence characterization of clinical and oyster Vibrio parahaemolyticus isolates
Jones JL , Ludeke CH , Bowers JC , Garrett N , Fischer M , Parsons MB , Bopp CA , Depaola A . J Clin Microbiol 2012 50 (7) 2343-52 In this study, 77 clinical and 67 oyster Vibrio parahaemolyticus isolates from North America were examined for biochemical profiles, serotype, and the presence of potential virulence factors (tdh, trh, and type III secretion system [T3SS] genes). All isolates were positive for oxidase, indole, and glucose fermentation, consistent with previous reports. The isolates represented 35 different serotypes, 9 of which were shared by clinical and oyster isolates. Serotypes associated with pandemic strains (O1:KUT, O1:K25, O3:K6, and O4:K68) were observed for clinical isolates, and 7 (9%) oyster isolates belonged to serotype O1:KUT. Of the clinical isolates, 27% were negative for tdh and trh, while 45% contained both genes. Oyster isolates were preferentially selected for the presence of tdh and/or trh; 34% contained both genes, 42% had trh but not tdh, and 3% had tdh but not trh. All but 1 isolate (143/144) had at least three of the four T3SS1 genes examined. The isolates lacking both tdh and trh contained no T3SS2alpha or T3SS2beta genes. All clinical isolates positive for tdh and negative for trh possessed all T3SS2alpha genes, and all isolates negative for tdh and positive for trh possessed all T3SS2beta genes. The two oyster isolates containing tdh but not trh possessed all but the vopB2 gene of T3SS2alpha, as reported previously. In contrast to the findings of previous studies, all strains examined that were positive for both tdh and trh also carried T3SS2beta genes. This report identifies the serotype as the most distinguishing feature between clinical and oyster isolates. Our findings raise concerns about the reliability of the tdh, trh, and T3SS genes as virulence markers and highlight the need for more-detailed pathogenicity investigations of V. parahaemolyticus. |
Risk factors for death among children less than 5 years old hospitalized with diarrhea in rural western Kenya, 2005-2007: a cohort study
O'Reilly CE , Jaron P , Ochieng B , Nyaguara A , Tate JE , Parsons MB , Bopp CA , Williams KA , Vinje J , Blanton E , Wannemuehler KA , Vulule J , Laserson KF , Breiman RF , Feikin DR , Widdowson MA , Mintz E . PLoS Med 2012 9 (7) e1001256 BACKGROUND: Diarrhea is a leading cause of childhood morbidity and mortality in sub-Saharan Africa. Data on risk factors for mortality are limited. We conducted hospital-based surveillance to characterize the etiology of diarrhea and identify risk factors for death among children hospitalized with diarrhea in rural western Kenya. METHODS AND FINDINGS: We enrolled all children <5 years old, hospitalized with diarrhea (≥3 loose stools in 24 hours) at two district hospitals in Nyanza Province, western Kenya. Clinical and demographic information was collected. Stool specimens were tested for bacterial and viral pathogens. Bivariate and multivariable logistic regression analyses were carried out to identify risk factors for death. From May 23, 2005 to May 22, 2007, 1,146 children <5 years old were enrolled; 107 (9%) children died during hospitalization. Nontyphoidal Salmonella were identified in 10% (118), Campylobacter in 5% (57), and Shigella in 4% (42) of 1,137 stool samples; rotavirus was detected in 19% (196) of 1,021 stool samples. Among stools from children who died, nontyphoidal Salmonella were detected in 22%, Shigella in 11%, rotavirus in 9%, Campylobacter in 5%, and S. Typhi in <1%. In multivariable analysis, infants who died were more likely to have nontyphoidal Salmonella (adjusted odds ratio [aOR] = 6.8; 95% CI 3.1-14.9), and children <5 years to have Shigella (aOR = 5.5; 95% CI 2.2-14.0) identified than children who survived. Children who died were less likely to be infected with rotavirus (OR = 0.4; 95% CI 0.2-0.8). Further risk factors for death included being malnourished (aOR = 4.2; 95% CI 2.1-8.7); having oral thrush on physical exam (aOR = 2.3; 95% CI 1.4-3.8); having previously sought care at a hospital for the illness (aOR = 2.2; 95% CI 1.2-3.8); and being dehydrated as diagnosed at discharge/death (aOR = 2.5; 95% CI 1.5-4.1). A clinical diagnosis of malaria, and malaria parasites seen on blood smear, were not associated with increased risk of death. This study only captured in-hospital childhood deaths, and likely missed a substantial number of additional deaths that occurred at home. CONCLUSION: Nontyphoidal Salmonella and Shigella are associated with mortality among rural Kenyan children with diarrhea who access a hospital. Improved prevention and treatment of diarrheal disease is necessary. Enhanced surveillance and simplified laboratory diagnostics in Africa may assist clinicians in appropriately treating potentially fatal diarrheal illness. Please see later in the article for the Editors' Summary. |
Drug-resistance mechanisms in Vibrio cholerae O1 outbreak strain, Haiti, 2010.
Sjolund-Karlsson M , Reimer A , Folster JP , Walker M , Dahourou GA , Batra DG , Martin I , Joyce K , Parsons MB , Boncy J , Whichard JM , Gilmour MW . Emerg Infect Dis 2011 17 (11) 2151-2154 To increase understanding of drug-resistant Vibrio cholerae, we studied selected molecular mechanisms of antimicrobial drug resistance in the 2010 Haiti V. cholerae outbreak strain. Most resistance resulted from acquired genes located on an integrating conjugative element showing high homology to an integrating conjugative element identified in a V. cholerae isolate from India. |
Characterization of toxigenic Vibrio cholerae from Haiti, 2010-2011.
Talkington D , Bopp C , Tarr C , Parsons MB , Dahourou G , Freeman M , Joyce K , Turnsek M , Garrett N , Humphrys M , Gomez G , Stroika S , Boncy J , Ochieng B , Oundo J , Klena J , Smith A , Keddy K , Gerner-Smidt P . Emerg Infect Dis 2011 17 (11) 2122-2129 In October 2010, the US Centers for Disease Control and Prevention received reports of cases of severe watery diarrhea in Haiti. The cause was confirmed to be toxigenic Vibrio cholerae, serogroup O1, serotype Ogawa, biotype El Tor. We characterized 122 isolates from Haiti and compared them with isolates from other countries. Antimicrobial drug susceptibility was tested by disk diffusion and broth microdilution. Analyses included identification of rstR and VC2346 genes, sequencing of ctxAB and tcpA genes, and pulsed-field gel electrophoresis with SfiI and NotI enzymes. All isolates were susceptible to doxycycline and azithromycin. One pulsed-field gel electrophoresis pattern predominated, and ctxB sequence of all isolates matched the B-7 allele. We identified the tcpETCIRS allele, which is also present in Bangladesh strain CIRS 101. These data show that the isolates from Haiti are clonally and genetically similar to isolates originating in Africa and southern Asia and that ctxB-7 and tcpETCIRS alleles are undergoing global dissemination. |
Burden of typhoid and paratyphoid fever in a densely populated urban community, Dhaka, Bangladesh
Naheed A , Ram PK , Brooks WA , Hossain MA , Parsons MB , Talukder KA , Mintz E , Luby S , Breiman RF . Int J Infect Dis 2010 14 Suppl 3 e93-9 BACKGROUND: We conducted blood culture surveillance to estimate the incidence of typhoid and paratyphoid fever among urban slum residents in Dhaka, Bangladesh. METHODS: Between January 7, 2003 and January 6, 2004, participants were visited weekly to detect febrile illnesses. Blood cultures were obtained at the clinic from patients with fever (≥38 degrees C). Salmonella isolates were assayed for antimicrobial susceptibility. RESULTS: Forty Salmonella Typhi and eight Salmonella Paratyphi A were isolated from 961 blood cultures. The incidence of typhoid fever was 2.0 episodes/1000 person-years, with a higher incidence in children aged<5 years (10.5/1000 person-years) than in older persons (0.9/1000 person-years) (relative risk=12, 95% confidence interval (CI) 6.3-22.6). The incidence of paratyphoid fever was 0.4/1000 person-years without variation by age group. Sixteen S. Typhi isolates were multidrug-resistant (MDR). All S. Paratyphi isolates were pan-susceptible. The duration of fever among patients with an MDR S. Typhi infection was longer than among patients with non-MDR S. Typhi (16+/-8 vs. 11+/-4 days, p=0.02) and S. Paratyphi (10+/-2 days, p=0.04) infections. CONCLUSIONS: Typhoid fever is more common than paratyphoid fever in the urban Bangladeshi slum; children<5 years old have the highest incidence. Multidrug resistance is common in S. Typhi isolates and is associated with prolonged illness. Strategies for typhoid fever prevention in children aged<5 years in Bangladesh, including immunization, are needed. |
Field evaluation of crystal VC Rapid Dipstick test for cholera during a cholera outbreak in Guinea-Bissau
Harris JR , Cavallaro EC , de Nobrega AA , Dos SBarrado JC , Bopp C , Parsons MB , Djalo D , Fonseca FG , Ba U , Semedo A , Sobel J , Mintz ED . Trop Med Int Health 2009 14 (9) 1117-21 OBJECTIVES: To evaluate performance characteristics and ease of use of the new commercially available Crystal VC Rapid Dipstick (VC) test (Span Diagnostics, India) for Vibrio cholerae O1 and O139. METHODS: Whole stool was collected from patients presenting to a hospital cholera ward during a 2008 epidemic in Guinea-Bissau. The VC test on stool samples was conducted on-site; samples were subsequently stored in Cary-Blair transport media and sent to the Centers for Disease Control and Prevention for diagnostic testing by culture and polymerase chain reaction (PCR). In addition, four local laboratory technicians who were unfamiliar with the test were provided with stool samples, the VC test kit, and simple written instructions and asked to perform the test and interpret results. RESULTS: A total of 101 stool specimens were collected and tested. Compared with PCR, the test was 97% sensitive and 71-76% specific. Laboratory technicians in Bissau performed the test and interpreted results correctly using only simple written instructions. CONCLUSIONS: The VC test may be useful for cholera diagnosis in outbreak situations where laboratory capacity is limited. |
Rapid identification of vibrio parahaemolyticus by whole-cell matrix-assisted laser desorption ionization-time of flight mass spectrometry
Hazen TH , Martinez RJ , Chen Y , Lafon PC , Garrett NM , Parsons MB , Bopp CA , Sullards MC , Sobecky PA . Appl Environ Microbiol 2009 75 (21) 6745-56 Vibrio parahaemolyticus is a pathogenic marine bacterium that is the main causative agent of bacterial seafood borne gastroenteritis in the United States. An increase in the frequency of V. parahaemolyticus-related infections during the last decade has been attributed to the emergence of an O3:K6 pandemic clone in 1995. The diversity of the O3:K6 pandemic clone and serovariants has been examined using multiple molecular techniques including multilocus sequence analysis (MLSA), pulsed-field gel electrophoresis (PFGE), and group-specific PCR (GS-PCR) analysis. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has become a powerful tool for rapidly distinguishing between related bacterial species. In the current study we demonstrate the development of a whole-cell MALDI-TOF MS method for the identification of V. parahaemolyticus from other Vibrio spp. We identified 30 peaks that were present only in the spectra of the V. parahaemolyticus strains examined in this study that may be developed as MALDI-TOF MS biomarkers for identification of V. parahaemolyticus. We detected variation in the MALDI-TOF spectra of V. parahaemolyticus strains isolated from different geographical locations and at different times. The MALDI-TOF MS spectra of the V. parahaemolyticus strains examined were distinct from the other Vibrios examined including the closely related V. alginolyticus, V. harveyi, and V. campbellii. The results of this study demonstrate the first use of whole-cell MALDI-TOF MS analysis for the rapid identification of V. parahaemolyticus. |
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