Day-to-day fluctuations of both circulating anodic antigen (CAA) and circulating cathodic antigen... more Day-to-day fluctuations of both circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) in serum and urine were examined simultaneously in a group of Schistosoma mansoni-infected individuals from Burundi and compared with each other and with fecal egg count fluctuations. Significant correlations were found between fecal egg counts and circulating antigens (CAA and CCA) and between circulating antigen levels in
Soil-transmitted helminth (STH) infections and zinc deficiency are often found in low- and middle... more Soil-transmitted helminth (STH) infections and zinc deficiency are often found in low- and middle-income countries and are both known to affect child growth. However, studies combining data on zinc and STH are lacking. In two studies in schoolchildren in Cuba and Cambodia, we collected data on height, STH infection and zinc concentration in either plasma (Cambodia) or hair (Cuba). We analyzed whether STH and/or zinc were associated with height for age z-scores and whether STH and zinc were associated. In Cuba, STH prevalence was 8.4%; these were mainly Ascaris lumbricoides and Trichuris trichiura infections. In Cambodia, STH prevalence was 16.8%, mostly caused by hookworm. In Cuban children, STH infection had a strong association with height for age (aB-0.438, p = 0.001), while hair zinc was significantly associated with height for age only in STH uninfected children. In Cambodian children, plasma zinc was associated with height for age (aB-0.033, p = 0.029), but STH infection was not. Only in Cambodia, STH infection showed an association with zinc concentration (aB-0.233, p = 0.051). Factors influencing child growth differ between populations and may depend on prevalences of STH species and zinc deficiency. Further research is needed to elucidate these relationships and their underlying mechanisms.
Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases, Jan 3, 2015
Infectious diarrhoea ranks among the leading causes of morbidity worldwide. While most acute diar... more Infectious diarrhoea ranks among the leading causes of morbidity worldwide. While most acute diarrhoeal episodes are self-limiting, diagnosis and treatment of persistent diarrhoea (≥2 weeks) are cumbersome and require laboratory identification of the causative pathogen. Stool-based PCR assays have greatly improved the previously disappointing pathogen detection rates in high-income countries, but there is a paucity of quality data from tropical settings. We performed a case-control study to elucidate the spectrum of intestinal pathogens in patients with persistent diarrhoea and asymptomatic controls in southern Côte d'Ivoire. Stool samples from 68 patients and 68 controls were obtained and subjected to molecular multiplex testing using the Luminex(®) Gastrointestinal Pathogen Panel (GPP), microscopy and rapid antigen detection tests for the diagnosis of diarrhoeagenic pathogens. Overall, 20 different bacteria, parasites and viruses were detected by the suite of diagnostic method...
Transmission of Schistosoma mansoni depends on fecal eggs reaching water, but the way this happen... more Transmission of Schistosoma mansoni depends on fecal eggs reaching water, but the way this happens is poorly understood. We studied the role of hygienic bathing after defecation in the contamination of water with S. mansoni eggs. Individuals in an endemic community in Northern Senegal (n=991) were examined for S. mansoni infection and a random sample (22%) was interviewed about stool disposal practices and hygienic behavior. We assessed the presence and viability of S. mansoni eggs adhering to the peri-anal region of 13 infected volunteers, by counting the miracidia in the water they had used for hygienic washing; for 10 of them (77%) miracidia were demonstrated. From the population infection distribution, average number of defecations per day, proportion of individuals bathing after defecation, and association between miracidial counts and infection intensity, we calculated a daily population miracidial output of approximately 30,000 through hygienic bathing. For comparison, one complete stool reaching the water was calculated to yield approximately 2500 miracidia. Thus, 12 individuals in this population should defecate into the water every day to produce the same number of miracidia as through hygienic bathing. Our results suggest a major role of hygienic bathing after defecation in the transmission of S. mansoni.
The American journal of tropical medicine and hygiene, 1999
Surprisingly low cure rates were repeatedly observed after treatment with a standard dosage of pr... more Surprisingly low cure rates were repeatedly observed after treatment with a standard dosage of praziquantel in a recently established Schistosoma mansoni focus in northern Senegal. In 4 discrete cohorts from the same population, cure rates were 18-36% and egg count reduction rates were 77-88%. Data and material of 920 compliant subjects from all 4 cohorts were further analyzed to identify possible host-related factors associated with low cure rates. The lowest cure rates were found in the highest egg count groups. However, in low and moderate egg count groups, drug efficacy was also below normal values. Cure rates were similar in males and females, showed no seasonal variation, and were independent of previous praziquantel treatment. They were significantly higher in adults than in children, also after allowing for intensity of infection. Individual water contact behavior and specific humoral immune responses were examined in 2 extreme subgroups, either without significant egg count...
The lack of epidemiological data on schistosomiasis (SCH) and soiltransmitted helminthes (STH) in... more The lack of epidemiological data on schistosomiasis (SCH) and soiltransmitted helminthes (STH) in the Democratic Republic of Congo (DRC) hampers effective disease control, although these diseases have a significant impact on population health. In 2009-2010 we conducted a random survey in school-aged children (3rd grade) in 11 health areas of the provinces Kinshasa and Bas-Congo. We collected socio-demographic data and examined stool and urine samples of each child. A total of 2399 children (1559 children from Kinshasa and 840 from Bas-Congo) were included. The overall prevalence of SCH was 13.5 %; CI95%: 12.1-14.8. The highest prevalence of SCH was found in Bas-Congo province (32.1; CI95%: 29-35.3). A total of 61.3 % (CI95%: 59.4-63.3) school-aged children were infected STH with a predominance of A. lumbricoides. This prevalence was higher in Kinshasa (64%; CI95%: 61.6-66.4) compared to Bas-Congo province (56.3%; CI95%: 53.4-60). The data generated in this study provide baseline dat...
School-aged children suffer the most from Schistosomiasis infections in Sub Saharan Africa due to... more School-aged children suffer the most from Schistosomiasis infections in Sub Saharan Africa due to poverty and limited sanitary conditions. Surveillance of disease burden is recommended and 20-year-old prevalence data needed urgent updating in the Democratic Republic of Congo. Epidemiological and parasitological study was carried out in 2011 in Health zone of Kasansa in Democratic Republic of Congo. Six health areas were included in the study. In each health area, one primary school was selected. Kato-Katz and direct microscopy examinations were performed in school-aged children. High Schistosoma prevalence levels (82.7%) were found in the Health Zone of Kasansa and certain study areas presented prevalence levels reaching nearly 100%. These results demonstrate that S. mansoni infection is a bigger problem than anticipated and there is an urgent need to implement effective control measures.
BackgroundRecently, a number of Global Health Initiatives (GHI) have been created to address sing... more BackgroundRecently, a number of Global Health Initiatives (GHI) have been created to address single disease issues in low-income countries, such as poliomyelitis, trachoma, neonatal tetanus, etc.. Empirical evidence on the effects of such GHIs on local health systems remains scarce. This paper explores positive and negative effects of the Integrated Neglected Tropical Disease (NTD) Control Initiative, consisting in mass preventive
Day-to-day fluctuations of both circulating anodic antigen (CAA) and circulating cathodic antigen... more Day-to-day fluctuations of both circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) in serum and urine were examined simultaneously in a group of Schistosoma mansoni-infected individuals from Burundi and compared with each other and with fecal egg count fluctuations. Significant correlations were found between fecal egg counts and circulating antigens (CAA and CCA) and between circulating antigen levels in
Soil-transmitted helminth (STH) infections and zinc deficiency are often found in low- and middle... more Soil-transmitted helminth (STH) infections and zinc deficiency are often found in low- and middle-income countries and are both known to affect child growth. However, studies combining data on zinc and STH are lacking. In two studies in schoolchildren in Cuba and Cambodia, we collected data on height, STH infection and zinc concentration in either plasma (Cambodia) or hair (Cuba). We analyzed whether STH and/or zinc were associated with height for age z-scores and whether STH and zinc were associated. In Cuba, STH prevalence was 8.4%; these were mainly Ascaris lumbricoides and Trichuris trichiura infections. In Cambodia, STH prevalence was 16.8%, mostly caused by hookworm. In Cuban children, STH infection had a strong association with height for age (aB-0.438, p = 0.001), while hair zinc was significantly associated with height for age only in STH uninfected children. In Cambodian children, plasma zinc was associated with height for age (aB-0.033, p = 0.029), but STH infection was not. Only in Cambodia, STH infection showed an association with zinc concentration (aB-0.233, p = 0.051). Factors influencing child growth differ between populations and may depend on prevalences of STH species and zinc deficiency. Further research is needed to elucidate these relationships and their underlying mechanisms.
Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases, Jan 3, 2015
Infectious diarrhoea ranks among the leading causes of morbidity worldwide. While most acute diar... more Infectious diarrhoea ranks among the leading causes of morbidity worldwide. While most acute diarrhoeal episodes are self-limiting, diagnosis and treatment of persistent diarrhoea (≥2 weeks) are cumbersome and require laboratory identification of the causative pathogen. Stool-based PCR assays have greatly improved the previously disappointing pathogen detection rates in high-income countries, but there is a paucity of quality data from tropical settings. We performed a case-control study to elucidate the spectrum of intestinal pathogens in patients with persistent diarrhoea and asymptomatic controls in southern Côte d'Ivoire. Stool samples from 68 patients and 68 controls were obtained and subjected to molecular multiplex testing using the Luminex(®) Gastrointestinal Pathogen Panel (GPP), microscopy and rapid antigen detection tests for the diagnosis of diarrhoeagenic pathogens. Overall, 20 different bacteria, parasites and viruses were detected by the suite of diagnostic method...
Transmission of Schistosoma mansoni depends on fecal eggs reaching water, but the way this happen... more Transmission of Schistosoma mansoni depends on fecal eggs reaching water, but the way this happens is poorly understood. We studied the role of hygienic bathing after defecation in the contamination of water with S. mansoni eggs. Individuals in an endemic community in Northern Senegal (n=991) were examined for S. mansoni infection and a random sample (22%) was interviewed about stool disposal practices and hygienic behavior. We assessed the presence and viability of S. mansoni eggs adhering to the peri-anal region of 13 infected volunteers, by counting the miracidia in the water they had used for hygienic washing; for 10 of them (77%) miracidia were demonstrated. From the population infection distribution, average number of defecations per day, proportion of individuals bathing after defecation, and association between miracidial counts and infection intensity, we calculated a daily population miracidial output of approximately 30,000 through hygienic bathing. For comparison, one complete stool reaching the water was calculated to yield approximately 2500 miracidia. Thus, 12 individuals in this population should defecate into the water every day to produce the same number of miracidia as through hygienic bathing. Our results suggest a major role of hygienic bathing after defecation in the transmission of S. mansoni.
The American journal of tropical medicine and hygiene, 1999
Surprisingly low cure rates were repeatedly observed after treatment with a standard dosage of pr... more Surprisingly low cure rates were repeatedly observed after treatment with a standard dosage of praziquantel in a recently established Schistosoma mansoni focus in northern Senegal. In 4 discrete cohorts from the same population, cure rates were 18-36% and egg count reduction rates were 77-88%. Data and material of 920 compliant subjects from all 4 cohorts were further analyzed to identify possible host-related factors associated with low cure rates. The lowest cure rates were found in the highest egg count groups. However, in low and moderate egg count groups, drug efficacy was also below normal values. Cure rates were similar in males and females, showed no seasonal variation, and were independent of previous praziquantel treatment. They were significantly higher in adults than in children, also after allowing for intensity of infection. Individual water contact behavior and specific humoral immune responses were examined in 2 extreme subgroups, either without significant egg count...
The lack of epidemiological data on schistosomiasis (SCH) and soiltransmitted helminthes (STH) in... more The lack of epidemiological data on schistosomiasis (SCH) and soiltransmitted helminthes (STH) in the Democratic Republic of Congo (DRC) hampers effective disease control, although these diseases have a significant impact on population health. In 2009-2010 we conducted a random survey in school-aged children (3rd grade) in 11 health areas of the provinces Kinshasa and Bas-Congo. We collected socio-demographic data and examined stool and urine samples of each child. A total of 2399 children (1559 children from Kinshasa and 840 from Bas-Congo) were included. The overall prevalence of SCH was 13.5 %; CI95%: 12.1-14.8. The highest prevalence of SCH was found in Bas-Congo province (32.1; CI95%: 29-35.3). A total of 61.3 % (CI95%: 59.4-63.3) school-aged children were infected STH with a predominance of A. lumbricoides. This prevalence was higher in Kinshasa (64%; CI95%: 61.6-66.4) compared to Bas-Congo province (56.3%; CI95%: 53.4-60). The data generated in this study provide baseline dat...
School-aged children suffer the most from Schistosomiasis infections in Sub Saharan Africa due to... more School-aged children suffer the most from Schistosomiasis infections in Sub Saharan Africa due to poverty and limited sanitary conditions. Surveillance of disease burden is recommended and 20-year-old prevalence data needed urgent updating in the Democratic Republic of Congo. Epidemiological and parasitological study was carried out in 2011 in Health zone of Kasansa in Democratic Republic of Congo. Six health areas were included in the study. In each health area, one primary school was selected. Kato-Katz and direct microscopy examinations were performed in school-aged children. High Schistosoma prevalence levels (82.7%) were found in the Health Zone of Kasansa and certain study areas presented prevalence levels reaching nearly 100%. These results demonstrate that S. mansoni infection is a bigger problem than anticipated and there is an urgent need to implement effective control measures.
BackgroundRecently, a number of Global Health Initiatives (GHI) have been created to address sing... more BackgroundRecently, a number of Global Health Initiatives (GHI) have been created to address single disease issues in low-income countries, such as poliomyelitis, trachoma, neonatal tetanus, etc.. Empirical evidence on the effects of such GHIs on local health systems remains scarce. This paper explores positive and negative effects of the Integrated Neglected Tropical Disease (NTD) Control Initiative, consisting in mass preventive
Uploads
Papers by Katja Polman